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1 IntroductionThis document describes the design of a Three-Phase Smart PowerMeter reference design based on NXP KM35Z512 microcontroller. Thismicrocontroller is a part of NXP Kinetis-M microcontroller family. Kinetis-Mmicrocontroller family designed for power metering applications. Therefore,the Kinetis-M family offers a high-performance Analog Front-End (24-bitAFE) combined with an embedded Programmable Gain Amplifier (PGA). Inaddition to high-performance analog peripherals, such as an auxiliary 16-bitSAR ADC, these new devices integrate memories, input-output ports, digitalblocks, and various communication options. The Arm® Cortex®-M0+ coreand Memory-Mapped Arithmetic Unit (MMAU), with support for 64-bit math,enable fast execution of metering algorithms. The three-phase power meterreference design is intended for the measurement and registration of activeand reactive energies in three-phase four-wire networks. This design is madeto be compliant with IS14697:1999 for class 0.5 accuracy for a dynamic rangeof 10-60 A.
The main purpose of a three-phase meter implementation on the KM3x devices is based on the signal’s dynamic range analysis.The current signal in metering is typically from 50 mA to 120 A, therefore the current must be digitalized by a very precise and linearADC with wide dynamic range, typically 24 bits. The SD method is an ideal solution to solve current dynamic range requirements.On the other hand, the voltage signal in metering is in the range of 80 V to 280 V. So the voltage dynamic range is approximately60 times smaller than current dynamic range. The voltage requirements can be easily solved by a high-resolution SAR converter.
The common reason for using six or seven independent ADC channels is for easier converter synchronization—that is, allchannels are able to begin precisely at the defined time. The KM3x devices solve this problem by the peripheral called XBAR.The XBAR is an internal connection matrix among the peripherals. Internal signals, such as conversion complete from the SDconverter can be used for starting SAR conversion. So the complete signal sampling process based on the combination of three orfour SDs and one SAR with an input multiplexer is fully supported by the device’s hardware and only the conversion results mustbe read by the microcontroller core or by DMA.
The three-phase power meter reference design is intended for the measurement and registration of active and reactive energiesin three-phase four-wire networks. It is pre certified according to the European EN50470-1, EN50470-3, classes B and C, and tothe IEC 62053-21 and IEC 62052-11 international standards for electronic meters of active energy classes 2, 1, and 0.5.
The integrated Switched-Mode Power Supply (SMPS) enables an efficient operation of the power meter electronics and providesenough power for optional modules, such as non-volatile memories (NVM) for data logging and firmware storage, a low-powermagnetic field sensor for electronic tamper detection, and an RF communication module for AMR and remote monitoring. Thepower meter electronics are backed-up by a 3.6 V Li-SOCI2 battery when disconnected from the power mains. This batteryactivates the power meter whenever the user button is pressed or a tamper event occurs. The permanent triggers for tamperevents include two tamper switches protecting the main and terminal covers. An additional optional tamper event is generatedby a low-power 3-axis magnetometer sensor. The 3-axis magnetometer is useful to check for magnetic field changes which isimportant because current sensing is widely used with current transformers. This type of sensor guarantees the static magneticfield generated by the permanent magnet.
The power meter reference design is prepared for use in real applications, as suggested by its implementation of a HumanMachine Interface (HMI) and communication interfaces for remote data collecting.
Contents
1 Introduction......................................12 MKM35Z512 series MCU................33 Basic theory.....................................44 Hardware design............................. 65 Software design............................ 176 Application setup...........................237 Accuracy and performance........... 258 Summary.......................................289 Metering board electronics............2810 Metering board layout................... 3311 Bill of materials of the metering board
...................................................... 3712 Bill of materials of the GPRS board
...................................................... 4013 References....................................4014 Revision history.............................40
AN13338KM35Z512 based Three-Phase Smart Power Meter ReferenceDesignRev. 0 — 25 November 2021 Application Note
This design is a reference for designing Smart Power Meter or Electricity Meter, which measures and displays Active Energy(kWh), Reactive Energy (kVArh) and Apparent Energy (kVAh). It also measures and displays Voltage, Current, frequency, Powerfactor, Active Power (kW), Reactive Power (kVAr), Apparent Power (kVA), Maximum demand in kW. It displays date and time.
1.1 SpecificationThe MKM35Z512 three-phase power meter reference design is intended for use in a real application. Its metrology portion hasundergone thorough laboratory testing. Thanks to intensive testing, accurate 24-bit AFE, and continual algorithm improvements,the three-phase power meter calculates active, reactive, and apparent energies more accurately and over a higher dynamic rangethan what is required by common standards. All information, including accuracies, operating conditions, and optional features, aresummarized in the following Table 1.
Table 1. MKM35Z512 three-phase power meter specification
Type of meter Three-phase AC static watt-hour smart meter
Type of measurement Four-quadrant
Metering algorithm Low-power real time based
Accuracy IS14697 class 0.5 (0.5 %)
Nominal voltage 240 VAC ± 20 %
Current range 0 – 60 A (10 A is nominal current, dynamic range is up to 72 A)
Nominal frequency 50 Hz ± 5 %
Meter constant (imp / kWh, imp / kVArh) 1600
Functionality V, A, kW, VAr, VA, kWh (import / export), kVArh (import / export), Hz, powerfactor, time, date
Voltage sensor Voltage divider
Current sensors Current Transformer (CT) with 2500:1 turn ratio
Energy output pulse interface Two red LEDs (active and reactive energy)
User interface (HMI) 8 x 15 segment LCD, one pushbutton
Tamper detection Two hidden buttons (module area and main cover)
IEC62056-21 infrared interface 9600 / 8-N-1 IR interface
Remote communication modules (optional only)
• GPRS
GPRS modules with 1 x SIM card slot, IPv6 capable module
External NVMs
• EEPROM
• Flash (optional only)
M240M2, 256 KB
IS25LQ040B, 512 KB
Internal battery 1/2AA, 3.6 V Lithium-Thionyl Chloride (Li-SOCI2) 1.2 Ah
Table continues on the next page...
NXP SemiconductorsIntroduction
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 2 / 42
Table 1. MKM35Z512 three-phase power meter specification (continued)
Power consumption @ 3.3 V and 22°C:
• Normal mode (powered from mains)
• Standby mode (powered from battery)
• Power-down mode (powered from battery)
11.0 mA 1
2.2 mA
12 μA (both covers closed, no tampering)
1. Valid for CORECLK = 23.986176 MHz and without any plugin communication module
2 MKM35Z512 series MCUNXP’s MKM35Z512 series MCU is based on the 90 nm process technology. It has on-chip peripherals, computationalperformance, and power capabilities to enable the development of a low-cost and highly integrated power meter (see Figure1). It is based on the 32-bit Arm® Cortex®-M0+ core, with CPU clock rated up to 75 MHz. The analog measurement front endis integrated on all devices; it includes a highly accurate 24-bit Sigma Delta ADC, PGA, high-precision internal 1.2 V voltagereference (Vref), phase shift compensation block, 16-bit SAR ADC, a high-speed analog comparator which allows to compareexternal signal with internal reference, a peripheral crossbar (XBAR), programmable delay block (PDB), and a memory-mappedarithmetic unit (MMAU). The XBAR module acts as a programmable switch matrix, enabling multiple simultaneous connectionsof internal and external signals. An accurate Independent Real-Time Clock (IRTC) with passive tamper detection capabilities isalso available on all devices.
In addition to high-performance analog and digital blocks, the MKM35Z512 series MCU was designed with an emphasis onachieving the required software separation. It integrates hardware blocks, supporting the distinct separation of the legally relevantsoftware from other software functions.
The hardware blocks controlling and/or checking the access attributes include:
• Arm Cortex-M0+ core
• DMA controller module
• Miscellaneous control module
• Memory protection unit
• Peripheral bridge
• General-purpose input/output module
NXP SemiconductorsMKM35Z512 series MCU
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 3 / 42
ArmCortex-M0+
75 MHz
CORE
AFETIMERS COMMUNICATION
INTERFACESHMI
SYSTEM MEMORIES CLOCKS
ANALOG
MMAU
SWD ANDMTB
16-bit SARADC
QUAD TIMERX4 CH
INTERRUPTCONTROLLER
24 bitΣ ADCPGA
SECURITY
UniqueID
PCRCSRAM64 KB
1 KHzLPO
32K OSC
MCG32K AND 4M IRC
FLL AND PLL
HIGHRANGE
OSC
WATCHDOG FLASH 512 KB, 2 256 KB banks
EWM
XBAR
LLWU
BME
DMA
HACMP x3
1.2 V VREF
MPU
MMCAU
24 bitΣ ADC
iRTC WITHTAMPER
PIT x2
SPI x3
I2C x2
UART x4(ISO7816 x2)LPUART x1
SEGMENTLCD
(> 288SEGMENGw/ 8MUX)
GPIOsPDB x1
LPTMR x2
iRTC
PGA
24 bitΣ ADCPGA
24 bitΣ ADC
PHASE SHIFTCOMPENSATION
PGA
VREF
Figure 1. KM35Z512 MCUs block diagramKM35Z512 MCUs block diagram
The MKM35Z512 devices are highly capable and fully programmable MCUs, with application software driving the differentiationof the product. Currently, the necessary SDK peripheral software drivers, metering algorithms, communication protocols,and a vast number of complementary software routines are available directly from semiconductor vendors or third parties.Because the MKM35Z512 MCUs integrate a high-performance analog front end, communication peripherals, hardware blocks forsoftware separation, and are capable of executing various Arm Cortex-M0+ compatible software, they are ideal components fordevelopment of residential, commercial, and light industrial electronic power meter applications.
3 Basic theoryThe critical task for a digital processing engine or an MCU in an electricity-metering application is the accurate computation ofthe active energy, reactive energy, active power, reactive power, apparent power, RMS voltage, and RMS current. The activeand reactive energies are sometimes referred to as the billing quantities. The remaining quantities are calculated for informativepurposes, and they are referred to as non-billing. A description of the billing and non-billing metering quantities and calculationformulas follows.
3.1 Active energyActive energy is the energy which is consumed or utilized in an AC Circuit is called true energy or Active Energy or real energy.The active energy is measured in the unit of Watt Hours (Wh). In electric power, real work is performed for the portion of the currentwhich is in phase with the voltage. No real work will result, from the portion where the current is not in phase with the voltage. Theactive energy in a typical three-phase power meter application is computed as an infinite integral of the unbiased instantaneousphase voltage u(t) and phase current i(t) waveforms.
Eq. 3-1
NXP SemiconductorsBasic theory
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 4 / 42
3.2 Reactive energyThe reactive energy is given by the integral (with respect to time) of the product of voltage and current, and the sine of the phaseangle between them. The reactive energy is measured in the unit of Volt-Ampere-Reactive Hours (VARh). The reactive energy ina typical three-phase power meter is computed as an infinite integral of the unbiased instantaneous shifted phase voltage u(t-90°)and phase current i(t) waveforms.
Eq. 3-2
3.3 Active powerThe active power (P) is measured in Watts (W), and it is expressed as a product of the voltage and the in-phase component of thealternating current. The average power of any whole number of cycles is the same as the average power value of just one cycle.Therefore, we can easily find the average power of a very long-duration periodic waveform simply by calculating the average valueof one complete cycle with period T.
Eq. 3-3
3.4 Reactive powerThe reactive power (Q) is measured in units of volt-amperes-reactive (VAR), and it is a product of the voltage and current, andthe sine of the phase angle between them. The reactive power is calculated in the same manner as the active power, but, in thereactive power, the voltage input waveform is shifted 90 degrees with respect to the current input waveform.
Eq. 3-4
3.5 RMS current and voltageThe Root Mean Square (RMS) is a fundamental measurement of the magnitude of an alternating signal. In mathematics, theRMS is known as the standard deviation, which is a statistical measure of the magnitude of a varying quantity. The standarddeviation measures only the alternating portion of the signal, as opposed to the RMS value, which measures both the direct andalternating components.
In electrical engineering, the RMS or effective value of a current is, by definition, such that the heating effect is the same for equalvalues of alternating or direct current. The basic equations for a straightforward computation of the RMS current and RMS voltagefrom the signal function are as follows:
Eq. 3-5
Eq. 3-6
3.6 Apparent powerThe total power in an AC circuit (both absorbed and dissipated) is referred to as the total apparent power (S). The apparent poweris measured in the units of volt-amperes (VA). For any general waveforms with higher harmonics, the apparent power is given bythe product of the RMS phase current and RMS phase voltage.
NXP SemiconductorsBasic theory
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 5 / 42
Eq. 3-7
For sinusoidal waveforms with no higher harmonics, the apparent power can also be calculated using the power triangle method,as a vector sum of the active power (P) and reactive power (Q) components.
Eq. 3-8
For a better accuracy, use Eq. 3-7 to calculate the apparent power of any general waveforms with higher harmonics. In purelysinusoidal systems with no higher harmonics, both Eq. 3-7 and Eq. 3-8 provide the same results.
3.7 Power factorThe power factor of an AC electrical power system is defined as the ratio of the active power (P) flowing to the load to the apparentpower (S) in the circuit. It is a dimensionless number ranging from –1 to 1.
Eq. 3-9
where angle
is the phase angle between the current and voltage waveforms in the sinusoidal system.
Circuits containing purely resistive heating elements (filament lamps, cooking stoves, and so on) have a power factor of one.Circuits containing inductive or capacitive elements (electric motors, solenoid valves, lamp ballasts, and others) often have apower factor below one.
4 Hardware designHardware design and stability are very important to achieve high accuracy and repeatability in power meter. High level hardwareblock diagram of power meter is shown in Figure 2. This section describes the power meter electronics, which are divided intothree separate parts:
• Power supply
• Digital circuits
• Analog signal-conditioning circuits
An active power source (Switch Mode Power Supply – SMPS) is chosen for this design. The power supply is designed to operatefrom three phases as well as single phase universal input mains voltage with secondary side regulation. Secondary side regulationprovides stable and well-regulated output voltage with minimal nose with respect to input voltage and output load variations. Alow-noise 3.6 V linear regulator, and a power management block is placed at power supply output to further reduce the noise.Total capacity of power supply output is 10 W max. The simple power management block works autonomously—that is, it suppliesstable power source to the power meter electronics from either the 50 Hz (60 Hz) mains or the 3.6 V Li-SOCI2 battery, which isalso integrated.
The basic configuration is comprised of only the circuits necessary for power meter operation; that means MCU(MKM35Z512VLL7), debug interface, LCD interface, LED interface, IR (IEC62056-21), GPRS module connector, relays,pushbutton, 256 KB I2C EEPROM and tamper detection. In contrast to the basic configuration, all the advanced features areoptional, and require the following additional components to be populated: 512 KB SPI Flash for firmware upgrade and/or datastorage. For more information, see Digital circuits.
The Kinetis-M devices allow differential analog signal measurements with a common mode reference of up to 0.8 V and aninput signal range of ±250 mV. The capability of the device to measure analog signals with negative polarity brings a significant
NXP SemiconductorsHardware design
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 6 / 42
simplification to the phase current sensors’ hardware interfaces. The phase voltage signal is connected to the SAR multiplexer,however, the external biasing circuits must be added externally.
Digital and analog circuit of the reference design is based on peripheral usage of the MCU and a block diagram is shown below.
LCD
KM35Z512
PMCGPIO
AUXBattery
SPI
UART
UART
SPI
SD-ADC
SAR-ADC
Power SupplySMPS
SWD IO/CLKJTAG debug
PowerManagement
Unit
I2C
OSC-PLL-FLL
iRTC
Connector for second MCU connection
Current transformerSense circuit
Voltage Sensecircuit
EEPROM(Meter app data)
EEPROM(FW storage)
32k Crystal
GPRS/LPRModule/RS232
Optical Port
Flash
Debug
MD-ResetButton
PushButton
CoverOpen
TamperSwitch
RTCBattery
CalibrationLEDs Relay Driver
MagnetTamper
ModuleOpenSwitch
TerminalOpenSwitch
Figure 2. KM35Z512 usage for three-phase smart meter
The power meter electronics were created using a two-layer printed circuit board (PCB). Two-layer PCB is cheaper andcost-effective. Figure 29 and Figure 30 show the top and bottom views of the power meter PCB, respectively.
4.1 Power supplySwitched Mode Power Supply (SMPS) has been developed using an offline high-voltage converter which features a 1050 Vavalanche-rugged power section, PWM operation at 60 kHz with frequency jittering for lower EMI, as shown in Figure 4. The powersupply provides 12 V for Latching relay operation and 5 V (2 A Max) for GPRS/RF module and other digital and analog circuit. Forstable and well-regulated output with low ripple SMPS is designed with secondary side feedback from 5 V. 5 V output is followed by3.6 V LDO for further reduction in output ripple and maintained very high regulation for input and output variation. 3.6 V generatedfrom LDO is used for energy measurement block and other digital circuit.
The following supply voltages are all derived from the regulated output voltage of the SMPS-LDO and auxiliary battery:
• RFV – 5 V supply used to supply GPRS module and backlight in the meter
• VCC – Fixed 3.6 V supply from SMPS-LDO that powers the GPRS modem or other types of wireless communicationmodules
• VDD is supported by VCC and VBAT_AUX (auxiliary 3.6 V Li-SOCI2 battery) – provides supply to digital and analogvoltage for the MCU and digital/analog circuits in case of VDD failure. MCU power pins VDD, VDDA, SAR_VDDA all arepowered through this.
NXP SemiconductorsHardware design
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 7 / 42
C93
0.1U
F
R235
0 DNP
VBAT_AUX
+C9210uF TV
S7C
DD
FN2-
T3.3
LC
12
BAT54CD57
3
1
2
VDDL21
1000OHM
1 2
VCC
UP_SCROLL (Pg2,5)
VBAT_AUX
TAMP_RF(Pg2)
R2221.0M
R231 0
VDD
R64470K
SW5
PB_SWITCH
1
2
3
6
5
4
VDD
BAT54C
D38
3
1
2
C69
0.1UF
R230 0
RF Open Tamper
VDD
Cover Open Tamper R232 0
R65470K
D62 BAT54HT1
DNP
A C
Terminal Open Tamper
Note: 1. When Top cover closed2-3 and 5-4 are shorted.2. When Top cover open2-1 and 5-6 are shorted.
Cover open and switches
VDD_SW
C420.1UF
D61 BAT54HT1
DNP
A C
R156 100K
C70
0.1UF
C43
0.1UF
Push Button Switch
D63 BAT54HT1
DNP
A C
SW2
PTS645
12
34
TAMP_COV(Pg2)
VBAT_AUX
SW4
PB_SWITCH
1
2
3
6
5
4
C410.1UF
DOWN_SCROLL (Pg2)
R1571.0M
R701.0M
Push Button Switch
RTC_BAT
SW1PTS645
12
34
TAMP_TERM(Pg2)
VBAT_AUX
SW3
PB_SWITCH
1
2
3
6
5
4
Q16PMV100XPEAR
1
2 3
BT2
ER14250-VB
12
3
BAT54C
D37
3
1
2
R153100K
C681.0UF
Q17
BC817-40LT1G
23
1
In absence of Mains, Battery supply not required everytime. Battery supply required for MCU wakeup by UP_SCROLL push button or cover open.
R15218K
LATCH(Pg4)
VBAT_AUX VDD_SW
R151 10K
UP_SCROLL(Pg4)
R102
0
D60
BAT54HT1
A C
Aux Battery Circuit
SMPS Output
Figure 3. Voltage source for the MCU in meter
MCU will not have any VDD when there is no AC mains. Auxiliary battery (VBAT_AUX) will provide VDD to MCU through D38whenever any switch SW3, SW4, and SW5 become active. MCU also gets VDD whenever switch SW2 (UP_SCROLL) is pressed.When SW2 switch is pressed, MCU software can activate the LATCH pin to latch the VBAT_AUX to MCU VDD.
The analog circuits within the MCU usually require decoupled power supplies for the best performance. The analog voltages(VDDA and SAR_VDDA) are supplied through VDD only and bypass capacitors C6, C7 are put close to the MCU analog voltagepins for better performance. Chip inductor L21 is placed between VDD and VCC to suppress the noise and provide clean voltagefor digital and analog measurement circuit.
C1000.22uF
C941000PF
+ C7633uF
C950.022UF
+C851000uF
D461N4007
AC
D501N4007
AC
+C97
1000uF
L19 1.2mH
1 2
C930.
1UF
R235
0 DNP
R18422
C752200PF
R19810K
C90
0.1U
F
R202
47
R187 22
VBAT_AUX
R_PH
DNP
C83
2200
PF
R180
470K
Y_PH1
DNP
D52
1N4007A C
B_PH2
DNP
MAINS_ON (Pg2)
+C9210uF TV
S7C
DD
FN2-
T3.3
LC
12
D49
1N4007
A C
RFV
R1911.0K
R196 0
L25 1.2mH1 2
R18
83.
3K
C96 1000pF
T1
EE20
5
3
4
1 67
9
10
82
NEUT
DNP
R190470
R2000
DNP
R211
47
R183470K
BAT54CD57
3
1
2
+C77
33uF
+C86
470uF
D45
MURS360T3G
A C
D54 US1M
AC
C88
0.1U
F
R199
10K
C91
0.1U
F
R225
B72210S2511K101
12
R213 2.7K
D481N4007
AC
R19318K
U23VIPER267KDTR
GN
D1
NC_12
NC_23
NA4
VDD
5
NC_36
FB7
COMP8
NC_49
NC_510
NC_611
NC_712
DRAIN_113
DRAIN_214
DRAIN_315
DRAIN_416
+C80
10UF
U22
ST732M36RGND
1
VIN2
VOUT3
NC14
NC25
R1921.0K
R_PH
R223B72210S2511K101
12
R201220K
R210 10 OHM
R204
47
D53 1N4007
AC
R182470K
VDDL21
1000OHM
1 2
Y_PH
U27TL431AIDBZR
1 3
2
D56 MURS120T3A C
C89
0.1U
F
C820.047UF
D55US1M
AC
R174100k
R212 2.7K
D47
1N4007
A C
D51
1N4007
A CB_PH
C81
0.1U
F
RLY_PWR
+C87
470uF
U25
TLV809K33DBVR
RES
ET2
VDD
3
GN
D1
RLY_PWR
R209 10 OHM
R203
47R181
470K
U24
FOD817A
1
23
4 R195
10K
DNP
R19422K
R189
10K
R224
B72210S2511K101
12
VCC
L23
3.3uH
1 2
Figure 4. SMPS power supply
The digital and analog voltages MCU VDD, VDDA, and SAR_VDDA are lower than the regulated output voltageVCC, due to a voltage drop on the diode D57 (0.35 V).
NOTE
NXP SemiconductorsHardware design
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 8 / 42
4.2 Digital circuitsAll the digital circuits are supplied from the VDD, and VCC voltages. The digital/analog common MCU voltage (VDD), which isbacked up by the 1/2AA 3.6 V Li-SOCI2 battery (BT2), is active even when the power meter electronics are disconnected from themains. It powers the MCU (U21), LEDs, isolated optical communication interface (U15, U16). The regulated output voltage (VCC)powers the digital circuits that can be switched off during the Standby and Power-down operating modes anyway. These are thecommunication modules which can be connected on connectors (J6, J7).
4.2.1 MKM35Z512VLL7The MKM35Z512VLL7 MCU (U1) is the most noticeable component on the metering board (see ). The following components arerequired for proper operation of this MCU:
• Filtering ceramic capacitors C1, C4, C6, C7, C8, C9, C52, C54
• LCD charge pump capacitors C10, C11, C13, C19
• External reset filters C2 and R1
• 32.768 kHz crystal Y1
The LCD (DS1) is an indispensable part of the power meter used to display billing and non-billing quantity. Debugger ConnectorJ1 is the SWD interface for MCU programming and debugging.
CAUTION:
The debug interface (J1) is not isolated from the mains supply. Use only galvanically isolated debug probes for programming theMCU when the power meter is supplied from the mains supply.
4.2.2 Output LEDsThe MCU uses a timer and GPIO pins to control two bright red LEDs D14 and D15 (see Figure 5; D14 for active energy,and D15 for reactive energy. These LEDs are used at the time of the meter calibration or verification as well as indication ofenergies calculations.
kWh_LED
VCC
R62 1.5K
D14
L-53LID
A C
R61 1.5K
VCC
kVArh_LEDD15
L-53LID
A C
Figure 5. Output LEDs control
4.2.3 KB I2C EEPROM memoryThe 256 KB I2C EEPROM memory (M24M02) can be used for parameter storage (backup of the calibration parameters) andother application purposes, for example, load profiles, billing, and even to store new application firmware. The connection of theEEPROM memory to the MCU is made through the I2C1 module, as shown in Figure 6. The maximum communication throughputis limited by the M24M02 device. The memory can work in both the Normal and Standby operation modes.
NXP SemiconductorsHardware design
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 9 / 42
R66
10.0K
I2C1_SCL
C620.1UF
I2C1_SDA
R63
10.0K
VDD
VDD
M24M02-DR
U18
DU_11
DU_22E2
3
VSS
4
SDA5
SCL6
WC7
VCC
8
VDD
Figure 6. 256 KB I2C EEPROM control
4.2.4 KB SPI flashThe 512 KB SPI Flash (IS25LQ040B-JNLE) can be used to store a new firmware application, and/or to store load profiles. Theconnection of the Flash memory to the MCU is made through the SPI0 module, as shown in Figure 7.
The SPI0 module of the MKM35Z512VLL7 device supports communication speed of up to 12.5 Mbit/s. The memory can work inboth the Normal and Standby operation modes.
VDD
IS25LQ040B-JNLE
U17
CE1
SO/IO12
WP/IO23
GN
D4
SI/IO05
SCK6
HOLD/IO37
VCC
8
SPI_MOSI
VDD
SPI_MISO
R145
10.0K
SPI_CK
C640.1UF
SPI_CS
Figure 7. 512 KB SPI flash control
4.2.5 GPRS module interfaceThe expansion headers J6 and J7 (see Figure 8) are used to interface the power meter to the GPRS modules. Currently, theysupport only the WM620 based GPRS module (see Figure 9). In the future, they will also support other types of modules, forexample, the 6 LowPAN LPR modules and so on. Header RFC4 provides the interconnection, while header RFC1 provides powersupply from the SMPS supply to the module itself. All of these modules accept supply voltage of 3.6 V or 5.0 V with a maximumcontinuous current of up to 2000 mA. Currently, these module connectors support below signals apart from power/ground pins:
• UART Tx, Rx data lines, RTS, CTS flow controls
• Low voltage 3.6 V, High voltage 5 V
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• NIC enable pin to enable/disable GPRS module resident power supply
RF_RXD
NIC_PC
J6
HDR_2X5
1 23 4
657 89 10
RFV
VCC
RF_TXD
RF_RTS
J7
HDR_2X5
1 23 4
657 89 10
VCC
RF_CTS
VCC
Figure 8. GPRS control
Figure 9. Extension for the GPRS communication
4.2.6 IR interface (IEC62056-21)The power meter has a galvanically isolated optical communication port, as per IEC62056-21 so that it can be easily connectedto a common handheld meter-reading instrument for data exchange. The IR interface is driven by the UART. Power to the IRinterface is provided by VDD. The IR interface schematic part is shown in Figure 10.
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R228 0
Q4TEFT4300
21
R571.0K
VDD
UART0_TXD
R60510
D12
TSAL4400
AC
R226 0
R227 0
VDD
LPUART0_TX
UART0_RXD
R229 0LPUART0_RX
Figure 10. IR control
Alternatively, this interface can be also used for waking up the meter (from the Power-down to the Standby mode)by an external optical probe. However, this feature has an impact on increasing the current consumption in bothoperation modes.
NOTE
4.2.7 Isolated RS-232 interfaceThis communication interface can be used primarily for real-time visualization using the FreeMASTER tool [6] or other means. Thecommunication is driven by the UART1 module of the MCU. The communication is optically isolated using the optocouplers U15and U16. As there is a fixed voltage level on these control lines generated by the PC, it is used to power the secondary side ofthe U15 optocoupler and the primary side of the U16 optocoupler. The communication interface, including the R87, R89, R142,R143, C53 components, are required to power the optocouplers from the transition control signals, is shown in Figure 11.
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PC_RXD
PC_VCC
PC_VCC
TXD
R892.2K
U15
FOD817A
1
23
4
R1431K
D331N4148
AC
PC_TXD
PC_TXD
J2
HDR_1X4
1234
R87 1.0K
D34
1N4148
AC
+ C5310UFU16
FOD817A
1
2 3
4
VDD
RXD
R1421.50K
PC_RXD
VDD
Figure 11. RS-232 control
The J2 output connector is not bonded to the meter’s enclosure. Therefore, the described interface is primarily usedat the time of development (uncovered equipment).
NOTE
4.2.8 Relay driverRelays are present in smart meter to cutoff the load from source input. Two PMV90ENE N channel trench MOSFETs are usedto drive the relays that are connected through J3 placed at the meter PCB. Relays are driven by MCU GPIO pins configured asoutput. Relay connectors are shown in Figure 12.
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RLY1_OFF
J3
HDR 1X3
123
R15947.0K
Q18PMV90ENE
1
2 3
D401N4007FL
AC
R16147.0K
+C72100UF
RLY1_ON D391N4007FL
AC
R160 1.0K
Q19PMV90ENE
1
2 3
R162
1.0K
RLY_PWR
Figure 12. Relay control
4.2.9 Magnetic tamperThere are two magnetic tamper sensors in the meter PCB. The first one is a hall-effect sensor which is used to sense any presenceof DC magnet near the meter. MCU interface is a GPIO pin input configuration. The second one is the 3D magnetic sensor andis not placed in the meter PCB and can be populated if required. This sensor is interfaced to MCU using I2C. Magnetic tampersense circuit is shown in Figure 13.
C66
0.1UF
R69100K
C44
0.1UF
VDD
VDDR14710.0K
C65
0.1UF
VDDVDD
VDD
SDA_MAG
R146
10.0K
TLV493D-A1B6
U20
SCL/INT1
SDA/ADDR6
VDD
4G
ND
_12
GN
D_2
3
GN
D_3
5
U19
AH180-WG
VDD1
GND2
OUT3
U5
AH180-WG
VDD1
GND2
OUT3 TAMP_MAG
SCL_MAG
Figure 13. Magnetic tamper sense circuit
4.2.10 Cover, module and terminal open tampersThere are options for 3 tampers detection in the meter PCB. Cover open tamper occurs when the cover of the meter is opened.MCU is signaled through tamper pin which is available in RTC battery power domain. The second one is the module open tamper
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KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 14 / 42
and is signaled when the GPRS module of the meter is removed or replaced. The third one is optional and called terminal opentamper and is detected when terminal of the meter is opened or closed. Tamper sense circuit is shown in Figure 14.
VBAT_AUX
TAMP_RF(Pg2)
R2221.0M
R231 0
SW5
PB_SWITCH
1
2
3
6
5
4
VDD
BAT54C
D38
3
1
2
C69
0.1UF
R230 0
RF open tamper
Cover open tamper R232 0
D62 BAT54HT1
DNP
A C
Terminal open tamper
Note: 1. When Top cover closed2-3 and 5-4 are shorted.2. When Top cover open2-1 and 5-6 are shorted.
VDD_SW
D61 BAT54HT1
DNP
A C
R156 100K
C70
0.1UF
C43
0.1UF
D63 BAT54HT1
DNP
A C
TAMP_COV(Pg2)
VBAT_AUX
SW4
PB_SWITCH
1
2
3
6
5
4
R1571.0M
R701.0M
RTC_BAT
TAMP_TERM
VBAT_AUX
SW3
PB_SWITCH
1
2
3
6
5
4
Figure 14. Tamper sense circuit
4.3 Analog circuitsAn excellent performance of the metering AFE, including external analog signal conditioning, is crucial for the power meterapplication. Due to the high dynamic range of the current measurement (typically 700:1) and the relatively low input signal range(from microvolts to several tens of millivolts), the phase current measurement is utmost critical. All analog circuits are describedin the following subsections.
4.3.1 Phase and neutral current measurementThe Kinetis-M three-phase power meter reference design is optimized for current transformers, but various Rogowski coils canalso be used. The only limitations are that the sensor output signal range must be within ±0.5 V peak and within the dimensionsof the enclosure. The interface of a current sensor to the MKM35Z512VLL7 device is very straightforward; a burden resistorfor current-to-voltage conversion and anti-aliasing low-pass filters attenuating signals with frequencies greater than the Nyquistfrequency must be populated on the board (see Figure 15). The cutoff frequency of the analog filters implemented on the boardis 72.3 kHz; such a filter has an attenuation of -33.3 dB at Nyquist frequency of 3.072 MHz. The burden resistor is a compositeformed by two resistors with the same value. The middle point of this is connected to ground.
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C260.033uF
R27 220R_CT2
L5
1000OHM
1 2R_CT1
SDADM3
L6
1000OHM
1 2
SDADP3
R1306.8
R23 220
C250.033uF
R1296.8
Figure 15. Phase current signal conditioning circuit
In addition to phase current measurement, due to the need to identification of current related tampers, such as earth tamper, theneutral current is also measured with a current transformer sensor. The current transformer gives isolation to the MCU AFE circuitas the ground of the circuit is referenced from the mains phase voltage. The neutral current signal conditioning circuit is shownin Figure 16.
R48 220
R21810.0K
N_CT1
SDADM0
R1366.8
SDADP0
R52 220
L13
1000OHM
1 2
L14
1000OHM
1 2N_CT2
C330.033uF
C340.033uF
R1356.8
Figure 16. Neutral current signal conditioning circuit
4.3.2 Phase voltage measurementA simple voltage divider is used for the line voltage measurement. As phase voltage is high voltage so multiple resistors are usedto meet the total resistor requirement as well as meet resistor voltage and energy dissipation stress (see Figure 17). One half ofthis total resistor consists of R111, R112, R113, and R115, the second half consists of resistor R139 (channel 1), R116, R117,R118, R119, and R140 (channel 2) and R121, R122, R123, R124, and R141 (channel 3). The resistor values were selected toscale down the 424.2 V peak input line voltage to the 0.4964 V peak input signal range of the 16 bit SAR ADC. The SAR ADC inputis unipolar different to bipolar SD ADC inputs. Hence, an external bias voltage must be added. External bias voltage is derivedfrom the on-chip reference voltage (taken from the VREF pin) and the value is the half of reference voltage. The bias voltage isconnected to the voltage diver through resistors R139, R140, and R141. The anti-aliasing low-pass filter of the phase voltagemeasurement circuit is set to a cutoff frequency of 27.22 kHz. Such an anti-aliasing filter has an attenuation of -41.0 dB at Nyquistfrequency of 3.072 MHz.
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R113
470K
R1392.20KR112
470K
R_PHR42 220R111
470K
R115
470K
L10
1000OHM
1 2
C300.047UF
R_PH_AD0
R_V
REF
/2
Figure 17. Phase voltages signal conditioning circuit
4.3.3 Half reference voltage generatorThe reference voltage half value is generated from internal voltage reference. Reference voltage 1.2 V is available on the VREFpin. This voltage is divided by two through the voltage divider R54 and R56. The half reference voltage is connected to the unitygain buffer where the optional filter capacity C39 is added. The unity gain buffer is a low cost and simple instrumentation amplifierU28 LMV324. A unity gain buffer is placed for phase voltage channel decoupling, therefore, the buffer works like an impedancetransformer. Figure 18 shows the schematic diagram of the half reference voltage generator.
VREF
VREF_CTRL
R_VREF/2
VREF_CTRL
C380.1UF
R5410K
VCC
B_VREF/2C570.1UF
Y_VREF/2
U28
LMV324IDR
OUT1
1IN-2
1IN+3
VCC+4
2IN+5
2IN-6
2OUT7
3OUT83IN-93IN+10GND114IN+124IN- 134OUT14
C56
0.1UF
R5610K
VREF_CTRLC58
0.1UF
C390.1UF
C550.1UF
Figure 18. Half reference voltage level generator
4.3.4 Zero crossing circuit connectionInternal comparator of MKM35Z512VLL7 is used for zero crossing detection. MKM35Z512VLL7 MCU has 3 high-speed analogcomparator with an integrated 6-bit DAC and analog mux. To optimize external circuit and reduce component count, same ADCpin used for phase voltage sensing can configure to positive or negative pin of internal comparator.
5 Software designThis section describes the software application of the MKM35Z512 three-phase power meter reference design. The softwareapplication consists of measurement, calculation, calibration, user interface, and communication tasks.
5.1 Block diagramThe application software is written in the C language and compiled using the IAR® Embedded Workbench for Arm (version 7.50.1),with high optimization for execution speed. The software application is based on the MKM35Z512 bare-metal software drivers [5]and the RMS and power converter-based metering algorithm library.
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The software transitions between operating modes, calculates all metering quantities, controls the active and reactive energypulse output, controls the LCD, stores and retrieves parameters from the NVMs, and enables application monitoring and control.The application monitoring and control is performed using local IR interface and a remote GPRS communication interface.
Figure 19 shows the software architecture of the power meter, including interactions of the software peripheral drivers andapplication libraries with the application kernel. All tasks executed by the MKM35Z512 three-phase power meter software arebriefly explained in the following subsections.
IR Interface(IEC82068-21)
UART0Driver
Customizablecommand interface
UART1Driver
UART3Driver
Phase-Locked Loop(PLL) Driver
Frequency-LockedLoop (PLL) Driver
GPIO and PORTDrivers
Reset ControllerModule (RCM) Driver
Low Power Timer(LPTMR) Driver
Non-volatile Memory(NVM) Driver EEPROM DriverSPI1 Driver
Parameter Sorage
I526LQ04-JNLE512 KB SPI flash
M24M02268 KB I2C EEPROM
I2C1 DriverFlash 2 KB sector(0x13400-0x13FFF)
GPRS driver
Independant R881Time Clock (IRTC)
Driver
Communications
Clock Management
Isolated R8232Interface
8 x 16 Segment LCDDisplay
Segment LCDController Driver
Applicationtasks
GPIO and PORTDrivers
Calibration Task(event triggered execution)
Operating Mode Control(executes after each POR)
Data Processing(executes periodically)
Tamper monitoring(event triggered execution)
HMI Control(execute periodically)
Calculation Billing andNon-billing Quantities(executes periodically)
Communication Tasks(event triggered execution)
Parameter ManagementTasks
(event triggered execution)
PUSH button
GPRS moduleInterface
32.788 kHzExternal Crystal
Tampers interface
Bare-metal drivers Libraries Application SW
ApplicationReset
Tampering
System ModeController (SMC)
Driver
Power ManagementController (PMC)
Driver
Power Management
System IntegrationModule (SIM) Driver
Voltage Reference(VREF) Driver
Watchdog (WDOG)Driver
Low LeakageWakeup (LLWU)
Driver
Device Initialization and Security
Analogue Front-End(AFE) and SAR ADC
Drivers
Phase Voltage andCurrents Signal
Conditioning Circuit
Low power real timeMetering Library
Peripheral Crossbar(XBAR) Driver
Analog Measurements and Energy Calculations
High-SpeedComparator (CMP)
Drivers
Quad Timer (TMR)Driver
GPIO and PORTDrivers
kWh and kVARhLEDs
Quad Timer (TMR)Driver
Phase Voltage Frequency Measurement
Pulse Output Generation
HMI
Figure 19. Software architecture
5.2 Software tasksThe software tasks are part of the application. They are driven by events (interrupts) generated either by the on-chip peripheralsor the application tasks. The list of all tasks, trigger events, and calling periods is summarized in the following table:
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Table 2. List of software tasks
Task name Description Source file(s) Function(s) name Trigger sourceIRQ
priority
Calling
period
Operatingmode control
Controlstransitioning
betweenpower meter
operating modes
IOControls.c
IOControls.hAppGPIOInit device reset – after every
device reset
HMI control
Updates LCD UserInterface.c Display QTMR interrupt Level 3(lowest) periodic 1 sec
Reads userbutton state Timer.c GPTimerEventHa
ndler QTMR interrupt Level 3(lowest)
asynchronous
Dataprocessing
Reads digital valuesfrom the SAR ADC
libmeterliblprt_cmp0p.a,
meterlprtlib_cm0p_iar.a,
meterlprtlib_cm0p_mdk.lib,
MeteringISR.c,
MeteringLPRT.h
SARADCCallbackSAR ADC
CH0,1,2 conversioncomplete IRQ
Level 1 periodic166.67 μs
Calculation Zero-cross detection MeteringISR.c TMR2callback
QTMR interrupt(CMP2 o/p triggering
QTMR through XBAR)Level 2 periodic 20
msec (50 Hz)
CalculationCalculation
billing and non-billing quantities
libmeterliblprt_cmp0p.a,
meterlprtlib_cm0p_iar.a,
meterlprtlib_cm0p_mdk.lib,
MeteringLPRT.h
DoMetering3Ph – – Periodic 1 sec
Pulsegeneration
LEDsdynamic pulse
output generationMeteringISR.c DoPulsing3Ph LPTMR0 compare flag
Level 0
(highest)
Periodicevery 1 msec
Tampermonitoring
Readstampers state
RTCDriver.c,
RTCDriver.hRTCEventHandler TAMPER1 active high,
TAMPER2 both edgesLevel 3(lowest)
asynchronous
Power metercalibration
Performs powermeter calibration
libmeterliblprt_cmp0p.a, DoCalibration3Ph UART interface – Command
through
Table continues on the next page...
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Table 2. List of software tasks (continued)
Task name Description Source file(s) Function(s) name Trigger sourceIRQ
priority
Calling
period
meterlprtlib_cm0p_iar.a,
meterlprtlib_cm0p_mdk.lib,
Calibration3Ph.h
UARTinterface
Parametermanagement
Reads parametersfrom the Flashand from the
external EEPROMMeteringRunIni
t.c,
Calibration3Ph.h
InitCalibration device reset – after everydevice reset
Writes parametersto the Flashand to the
external EEPROM
UpdateFlashCalib,ReadVerifyFlashC
alib,ReadVerifyCalib
after successfulcalibration, controlled
by user, orswitching off
– asynchronous
1. A special load point must be applied by the test equipment
5.2.1 Power meter calibrationThe power meter is calibrated using a special test equipment. The calibration task runs whenever a power meter is connected tothe mains and a calibration command is triggered through IR communication interface. Calibration is done on fix point of voltage(240 Vac), current (10 A) and power factor (0.5L, 60 degree phase angle). The running calibration task measures the phasevoltage and phase current signals generated by the test equipment, and it expects 240 V phase voltage and 10.0 A phase currentwaveforms with a 60 degree phase shift (lag). The voltage and current signals must be the first harmonic (fundamental) only. Allthese values should be precise and stable during the calibration itself; the final precision of the power meter strongly depends onit. If the calibration task detects such a load point, then the calibration task calculates the calibration gains and phase shift usingthe following equations:
gainU = 240.0/URMS Eq. 5-1
gainI = 10.0/IRMS Eq. 5-2
θ = 60ο - tan-1 (Q/P) Eq. 5-3
where:
gainU and gainI are calibrated gains
θ is the calculated phase shift caused by the parasitic inductance of the shunt resistor or current transformer
URMS, IRMS, P, Q are quantities measured by the non-calibrated meter
The calibration task terminates by storing the calibration gains and phase shifts into two non-volatile memories; the internal Flashmemory and the external EEPROM memory (backup storage). The recalibration of the power meter can be reinitiated later also.For more details on the calibration process, see AN12827.
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KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 20 / 42
5.2.2 Operating mode controlThe transitioning of the power meter electronics between the operating modes helps to maintain a long battery lifetime. The powermeter software application supports the following operating modes:
• Normal: Electricity is supplied and the power meter is fully functional
• Standby: Electricity is disconnected. And, you can list through the menus and also can communicate with the meter usingIR interface
• Power-down: Electricity is disconnected with no user interaction
Figure 20 shows the transitioning between the supported operating modes. After the battery or the mains is connected, the powermeter transitions to the Device Reset state. If mains is applied, hardware generates MAINS_ON signal which is connected to MCUGPIO pin. Status change in MAINS_ON pin trigger the software application to enter into the Normal mode operation. In Normalmode all software tasks including calibration, measurements, calculations, HMI control, parameter storage, pulse generation,tamper management, and communication, are executed. In this mode, the MKM35Z512VLL7 device runs in the RUN mode.The system core and Flash clock frequency are generated by the frequency-locked loop (FLL), and it is 23.986 MHz. The AFEclock frequency is generated by the phase-locked loop (PLL), and it is 12.288 MHz. The power meter electronics consume 11.0mA in the Normal mode.
Stand-By Mode
Device Reset
Device Switched
OFF
Power-down Mode
electricity applied
electricity disconnected or user button pressed
Normal Mode
electricity applied
electricity disconnected
Inserted battery or electricity
applied
battery removed and electricity disconnected
Cover & GPRS Module closed,electricity
disconnected and 20 seconds timeout elapsed
Cover/GPRS Module open,electricity
disconnected and 20 seconds timeout elapsed
electricity applied or
user buttonpressed
pressing user button refreshes
20 seconds
battery supply present
Cover & GPRS Module closed,electricity
disconnected Cover & GPRS Module open,electricity
disconnected
Figure 20. Operating modes
If mains is not applied, then the software application enters the Switched OFF state. Once the mains is applied, meter entersin Normal mode. As soon as electricity is disconnected, meter switches back to Switched OFF mode provided meter cover andGPRS module is kept inserted in the meter. If either of those are open, then the meter enters in Power-down mode when theelectricity is disconnected and if a battery is connected to the meter. If user button is pressed, the software then enters the standbymode. This mode transitions between the Normal mode and the Switched-off mode with a duration of only 20 seconds refreshtimeout. The power meter runs from the battery during standby mode, and in this mode user can list through the menus andcan also download meter billing and non-billing quantities through IR interface only. In this mode, the MKM35Z512VLL7 devicefunctions in the RUN mode with much reduced MCU clock to save power. The system clock frequency is scaled down to 2MHz from the 4 MHz internal relaxation oscillator. Because of the slow clock frequency, the limited number of enabled on-chipperipherals, the power consumption of the power meter electronics is approximately 2.2 mA.
When the power meter runs from the battery (standby mode) but user does not list through the menus, then the softwaretransitions automatically to the Switched OFF mode. The MKM35Z512VLL7 device is forced to enter the Very Low Leakage Stop
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2 (VLLS2) mode, where the recovery can be triggered by pressing the user button or applying the mains. The Power-down modeis characterized by a battery current consumption of 12 μA.
5.2.3 Data processingReading all the phases and neutral currents samples from the analog front end (AFE) and all the phases voltages fromSAR ADC periodically every 166.67 μsec. This task runs on the high priority level. AFE runs continuous conversion modeasynchronously and SAR ADC is configured in trigger conversion mode. Each AFE (assigned for taking current samples)triggered its corresponding SAR ADC channels to take voltage sample of respective phases at same time AFE sample conversioncompletes. Both current samples (AFE result register) and voltage samples (SAR ADC result register) of respective phases isbeen collected in buffers at respective SAR ADC conversion complete interrupt. Calculation task is been initiated once requirednumber of samples of voltages and currents is been stored in buffer.
Each phase current sample from AFE and each phase voltage from SAR ADC are taken continuously at a constantrate of 6000 samples per second. This can be achieved by setting AFE modulator clock and over sampling ratio(OSR) accordingly for example, in low-power AFE mode, setting AFE modulator clock to 768 KHz and OSR to 256.Although in normal AFE mode, higher modulator clock and OSR value can be set to achieve desired sample rate.
NOTE
5.2.4 CalculationsThis separate task monitors the mains zero-crossings, which is used to calculate frequency in the timer handler callback functionitself. Apart from that, the main calculation process computes both the billing (energies) and the non-billing quantities. This is doneperiodically at the end of every one second.
At this time, all circle buffers are filled up with the AFE and SAR ADC results. Firstly, the calculation task performs theDoMetering3Ph which calculates all instantaneous parameters of all phases including Vrms, Irms, Phase angle, and Powers.This calculation process uses the calibration gains obtained during the calibration stage (see Power meter calibration).DoCalibration3Ph function is used to do calibration of the meter depending on a user command received through IRcommunication interface.
Finally, the billing quantities is computed and the energy LED pulsing is done by another independent task DoPulsing3Ph.
5.2.5 HMI controlThe Human Machine Interface (HMI) control task executes continuously for LCD display and pushbutton events. Using shortkeypress, the LCD parameters can be scrolled through a pre-defined list of billing and non-billing parameters. But after pressingthe key for a longer duration once, the display mode can be changed to High resolution mode where subsequent short durationkeypresses display billing and non-billing parameters with higher resolutions. The display mode reverts back to regular resolutionmode after a predefined time is elapsed.
5.2.6 Main loop processingMain loop of the application software runs all the tasks like Data processing, checking and storing tamper/events, communicationtasks, checking for power mode change, reads the real-time clock and refreshes the watchdog. The interaction with the user ismade through an asynchronous event, which occurs when the user button is pressed. By pressing the user button, you are ableto scroll through the menus and display all measured and calculated quantities (see Figure 22).
5.2.7 Tamper monitoringThere are two hidden mechanical pushbuttons. One button is used for the main cover opening detection, and the second buttonis used for the GPRS module removal or insertion detection. There is an optional third pushbutton to detect the terminal coveropening. By default, this pushbutton is not populated on meter PCB. These asynchronous events are read as the IRTC interrupt,those are stored in the memory, and shown on the LCD continuously. The other tampers which are monitored are magnetic tamperand few other electrical tamper conditions the detection logic of which are beyond the scope of this document.
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5.2.8 IR port communicationIR port communication is done as part of Communication task. A proprietary set of communication commands has been utilized tocommunicate with the meter for few tasks for example calibration of the meter, reading billing and non-billing quantities, readingor setting meter clock etc. UART0 has been used for this interface.
5.2.9 GPRS port communicationGPRS module communication is done as part of Communication task. GPRS module is connected through UART3 of the MCU.The application software utilizes AT command interface to communicate with the GPRS mode. The communication protocol forremote communication through GPRS is beyond the scope of this document. GPRS communication enables AMI (or AMR) meterreading from remote location.
5.2.10 Parameter managementThe current software application uses 2048 byte sector of the internal MKM35Z512VLL7 Flash memory for parameter storage.There is also an external 256 KB EPROM memory used for the same purpose, but as a backup storage (optional only). By default,the parameters are written after a successful calibration, and they are read after each device reset. The main purpose for usingthese non-volatile memories like EEPROM is to save all the other meter parameters. Storing and reading of parameters can alsobe initiated through the IR or GPRS communication interface using proprietary tool or protocol specific standard tools used bypower meter OEMs or utilities.
5.3 PerformanceTable 3 shows the memory requirements of the MKM35Z512 three-phase power meter software application[1].
Table 3. Memory requirements
Function DescriptionFlash size
[KB]
RAM size
[KB]
Application framework Complete application without all libraries and communication 44.214 4.174
Low-power real timemetering library Low-power real time metering algorithm library 6.037 2.262
EEPROM driver EEPROM driver 1.1202 0.0136
Proprietary communication Proprietary protocol and serial communication driver 6.182 1.334
Grand total 57.564 7.784
The device system clock is generated by the FLL (except for the AFE clock). In the Normal operating mode, the FLL multiplies theclock of an external 32.768 kHz crystal by a factor of 732, hence generating a low-jitter system clock with a frequency of 23.986176MHz. Such system clock frequency is sufficient for executing a fully functional software application.
6 Application setupFigure 21 shows the wiring diagram of the MKM35Z512 three-phase power meter.
Registering the active and reactive energy consumed by an external load is among the main capabilities of the power meter. Whenuser connects the power meter to the mains or when user press the user button, the power meter transitions from the Power-downmode to either the Normal mode or the Standby mode, depends up on mains present or absent. In the Normal and Standby modes,
[1] Application is compiled using the IAR Embedded Workbench for Arm, with high optimization for execution speed.
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KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 23 / 42
the LCD is turned on, and it shows the last calculated quantity. List through the menus and display other quantities by pressingthe user button. All configuration and informative quantities accessible through the LCD are summarized in Table 4.
Figure 21. MKM35Z512 three-phase power meter wiring diagram
Table 4. The LCD menu item list
Value Unit Format Auxiliary symbols
Line voltage VRMS ###.## V
Phase line current ARMS ###.## A
Neutral line current ARMS ###.## A
Signed active power P W #.## (+ forward, – reverse) W
Signed reactive power Q VAr #.## (+ lag, – lead) VA, r
Apparent power S VA #.## VA
Power factor – #.### PF
Frequency Hz #.### Hz
Table continues on the next page...
NXP SemiconductorsApplication setup
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 24 / 42
Table 4. The LCD menu item list (continued)
Value Unit Format Auxiliary symbols
Date – DD:MM:YY –
Time – HH:MM:SS –
Meter serial number – ######## –
Figure 22 shows the values and special symbols on the power meter display. This figure displays the following display parameters– line voltage, phase current, cumulative active energy, date, time, all segment ON.
Figure 22. MKM35Z512 three-phase smart power meter display
The active energy LED flash simultaneously with the internal energy counters during the Normal operation mode. The activeenergy LED is the sum of both active energies (imported and exported). All these active and reactive energy counters areperiodically saved every 3 minutes into the external EEPROM memory (backup storage). These energy quantities remain in thememory after resetting the power meter.
7 Accuracy and performanceThe MKM35Z512 three-phase reference designs are fully calibrated using the test equipment ST6300V2. All power meters weretested according to the IS14697 class 0.5 (0.5 %) Indian standards for electronic meters.
During the calibration and testing process, the power meter measured electrical quantities generated by the test bench ST6300V2,calculated the active energy, and generated pulses on the output LED; each generated pulse was equal to the active energyamount in kWh/ imp. The deviations between the pulses generated by the power meter and the reference pulses generated bythe test equipment defined the measurement accuracy.
Figure 23 shows the accuracy plot of NXP MKM35Z512 three-phase smart power meter. The figure indicates the results of thepower meter accuracy performed at 25°C. The accuracy of the measurement for various phase currents, various phase voltages,various frequency values and the angles between phase current and phase voltage, are shown in the graph.
The graph (on the top) indicates the accuracy of the active energy measurement after calibration. The x-axis shows thevariation of the phase current, and the y-axis denotes the average accuracy of the power meter, computed from five successivemeasurements. The two bold red lines define the Class 0.5 (IS14697) accuracy margins for active energy measurement for powerfactor 1 for this test.
The second graph shows the accuracy of the active energy after calibration. The x-axis shows the variation of the phase voltage,and the y-axis denotes the average accuracy of the power meter, computed from five successive measurements. The two boldred lines define the Class 0.5 (IS14697) accuracy margins for active energy measurement for power factor 1 for this test.
The third graph shows the accuracy of the active energy after calibration. The x-axis shows the variation of the frequency, and they-axis denotes the average accuracy of the power meter, computed from five successive measurements. The two bold red linesdefine the Class 0.5 (IS14697) accuracy margins for active energy measurement for power factor 1 for this test.
NXP SemiconductorsAccuracy and performance
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 25 / 42
By analyzing the protocols of several MKM35Z512 three-phase power meters, this equipment measures active and reactiveenergies at all power factors, at 25°C ambient temperature, and in the current range of 0.1 – 90 A, with the accuracy range of±0.25 %.
CAUTION:
Even though the current range of the power meter is scaled to 90 A, it is not recommended to operate the power meter in the 60– 90 A range for a longer time period, due to heating of the single turn primary winding of current transformer.
NXP SemiconductorsAccuracy and performance
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 26 / 42
In (A)0 6030 40 502010
-0.4
0
0.4
0.2
-0.2
-0.6
0.6
0.8
+ ERR(%) Limit PF=1
ERR(%)
-0.8
- ERR(%) LimitPF=0.5(L) PF=0.8(C) PF=0.25(L) PF=0.5(C)
Voltage (V)140 300220 260 280200160 240180
-0.2
0
0.2
0.1
-0.1
-0.3
-0.4
0.3
0.4
0.5
+ ERR(%) Limit PF=1
ERR(%)
-0.5
PF=0.5(L) PF=0.5(L) PF=0.8(L) - ERR(%) Limit
frequency (Hz)43 5751 554945 5347
-0.2
0
0.2
0.1
-0.1
-0.3
-0.4
0.3
0.4
0.5
+ ERR(%) Limit PF=1
ERR(%)
-0.5
PF=0.5(L) PF=0.8(C) - ERR(%) Limit
Figure 23. Accuracy results at 25°C
NXP SemiconductorsAccuracy and performance
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 27 / 42
8 SummaryThis design reference manual describes a solution for a three-phase smart electronic power meter, based on theMKM35Z512VLL7 MCU.
NXP offers Fast Fourier Transform (FFT), Filter-based and low-power and real time-based metering algorithms for use in customerapplications. The FFT based metering algorithm calculates the metering quantities in the frequency domain, the latter two doesthe same in the time domain. This reference manual explains the basic theory of power metering, and lists all the equations to becalculated by the power meter.
The hardware platform of the power meter is algorithm-independent, so the application firmware can leverage any type of meteringalgorithm, based on customer preference. To extend the power meter uses, the hardware platform comprises either 256 KBEEPROM for data storage and firmware upgrade and also an optional 512 KB SPI Flash for firmware upgrade, and an expansionheader for GPRS module for AMI communication and monitoring.
The application software is written in the C language, and compiled using MCUXpresso, IAR Embedded Workbench for Armand Keil tool chains, with optimization for the execution speed. It is based on the MKM35Z512 SDK driver software drivers andthe Low-Power Real-Time (LPRT) metering library as default. The application firmware calibrates the power meter through IRcommand, calculates all metering quantities, controls active energy pulse output and the LCD, stores and retrieves parametersfrom the Flash and EEPROM memory. The application software of such complexity requires approximately 58 KB of Flash and 8KB of RAM. The system clock frequency of the MKM35Z512VLL7 device must be 24.576 MHz (or higher) to calculate all meteringquantities with an update rate of 6 kHz(the sample rate).
The power meter is designed to transition between three operating modes. It runs in the Normal mode when it is powered fromthe mains. In this mode, the meter electronics consume 11.0 mA. The Standby mode is entered when the power meter runs fromthe battery and the user lists through the menus. In this particular mode, the 3.6 V Li-SOCI2 (1.2 Ah) battery is being dischargedby 2.2 mA as it also measures currents current channels. When the power meter runs from the battery but no interaction with theuser occurs, the power meter electronics automatically transition to the Switched OFF mode.
The application software enables you to monitor the measured and calculated quantities through the proprietary applicationrunning on your PC. The IR communication interface is used for such communication. Another very important means of AMI (orAMR) communication is through GPRS communication module.
The MKM35Z512 three-phase smart power meters were tested according to the IS14697 Indian standard for static watt-hourmeters for Class 0.5 accuracy. After analyzing several power meters, we can state that this smart power meter measures activeenergies at all power factors, at 25°C ambient temperature, in the current range of 0.1 – 72 A, with an accuracy range of ±0.25 %.
9 Metering board electronicsThree-phase power meter hardware schematic is shown in this section. schematic has four major sections: MCU, Analog sensing,user interface, and power supply.
NXP SemiconductorsSummary
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 28 / 42
C90.1uF
LCD_6(Pg4)
DOWN_SCROLL(Pg4)
RLY1_ON(Pg2)
LCD_20(Pg4)
VDD
A
VCAP
2
VDD
RF_RTS(Pg4)
TAMP_RF (Pg4)
R234
10K
XTAL32K
Debugger Connector
SPI_CS(Pg4)
C190.1uF
VDD
LCD_0(Pg4)
VDD
TVS3
CDDFN2-T3.3LC
12
SAR
_VD
DA
LCD_5(Pg4)
SCL_MAG(Pg4)
RLY1_OFF(Pg2)
Drawing Title:
Size Document Number Rev
Date: Sheet of
Page Title:
Designer:
Drawn by:
Approved:
Microcontroller Solutions Group6501 William Cannon Drive WestAustin, TX 78735-8598
This document contains information proprietary to NXP and shall not be used for engineering design, procurement or manufacture in whole or in part without the express written permission of NXP Semiconductors.
Classification:NXP SEMICONDUCTORS©
<Doc> 1.1
PKM35Z512VLL7_3PHSM
C
Wednesday, September 29, 2021
01_MCU
Banwari lal
Kamil & Biswanath
Banwari lal
2 5
<PUBI><FIUO><FCP>
VREFL
VLL1
C544.7uF
SDADP1 (Pg3)
LCD_1(Pg4)
RLY1_OFF(Pg2)
VDD2
J3
HDR 1X3
123
SDADM3 (Pg3)
C70.1uF
SPI_MISO(Pg4)
Note: R,Y,B phase ADC inputs should be alsoconnected to CMP input seperately for KM3xZ128 MCUs.For KM3xZ256/KM35Z512 other ADC pins might not provide CMP support. Check in Reference Manual.
LCD_10(Pg4)
LATCH(Pg5)
C60.1uF
TXD(Pg4)
LCD_19(Pg4)
TAMP_MAG(Pg4)
VCAP2
EXTAL32K
TVS6
CD
DFN
2-T3
.3LC1
2
RESET
LCD_2(Pg4)
C521.0UF
LCD_16(Pg4)
VDD
C210nF
VLL1
VBAT
LCD_22(Pg4)
R15947.0K
SDADM0 (Pg3)
SPI_MOSI(Pg4)
LCD_9(Pg4)
Q18PMV90ENE
1
2 3
RXD(Pg4)
VREF
H
LCD_21(Pg4)
VLL3
D401N4007FL
AC
Relay drive
NIC_PC(Pg4)
VDD1
RF_CTS(Pg4)
LCD_14(Pg4)
SWD_IO
TP3
Y1AB26T-32.768KHZ
12
SDADM2 (Pg3)
VLL3
TP2
LCD_8(Pg4)
VREF_CTRL(Pg3)
kWh_LED(Pg4)
TP1
J1
HDR 1X5
12345
R208
0
VLL2
R16147.0K
I2C1_SCL(Pg4)
+C72100UF
TVS1
CD
DFN
2-T3
.3LC1
2
SAR_VDDA
RF_RXD(Pg4)
LCD_13(Pg4)
LCD_18(Pg4)
RLY1_ON(Pg2)
SDADP2 (Pg3)
VDD
1
SDADP3 (Pg3)
RESET
LCD_7(Pg4)
SDADM1 (Pg3)
kVArh_LED(Pg4)
C80.1uF
GPIO_NC2(Pg4)
VREF (Pg3)
R233100K
DNP
Decoupling Capacitors
I2C1_SDA(Pg4)
C100.1uF
D391N4007FL
AC
LCD_12(Pg4)
RTC_BAT
RF_TXD(Pg4)
EXTAL32K
VDD
VREF
L
TVS2
CD
DFN
2-T3
.3LC1
2
UP_SCROLL(Pg4,5)
R160 1.0K
GPIO_NC1(Pg4)
LCD BIAS and charge pump capacitors
C40.1uF
R110.0K
VDDSWD_CLK
VDD
LCD_11(Pg4)
R_PH_AD0(Pg3)
C110.1uF
VDDA
UART0_TXD(Pg4)
32.768K crystal
LPUART0_TX(Pg4)VCAP1
C10.1uF
LCD_15(Pg4) XTAL32K
VCAP
1
LCD_4(Pg4)
B_PH_AD2(Pg3)
LCD_17(Pg4)
VDD
2
Q19PMV90ENE
1
2 3
SWD_IO
R162
1.0K
MKM35Z512VLL7
U21
PTA0/LLWU_P16/LCD_P231
PTA1/LCD_P242
PTA2/LCD_P253
PTA3/LCD_P264
PTA4/LLWU_P15/NMI/LCD_P275
PTA5/CMP0_OUT/LCD_P286
PTA6/LLWU_P14/XBAR0_IN0/LCD_P297
PTA7/XBAR0_OUT0/LCD_P308
PTB0/LCD_P319
PTB1/LLWU_P17/LCD_P3212
PTB2/LCD_P33/SPI2_PCS013
PTB3/LCD_P34/SPI2_SCK14
PTB4/LCD_P35/SPI2_MISO15
PTB5/LCD_P36/SPI2_MOSI16
PTB6/LCD_P37/CMP1_IN017
PTB7/LCD_P38/AFE_CLK18
PTC0/LCD_P39/UART3_RTS/XBAR0_IN1/PDB0_EXTRG19
PTC1/LCD_P40/CMP1_IN1/UART3_CTS20
PTC2/LCD_P41/UART3_TX/XBAR0_OUT121
PTC3/LLWU_P13/LCD_P42/CMP0_IN3/UART3_RX22
PTC4/LCD_P4323
PTC5/LLWU_P12/ADC0_SE0/CMP2_IN0/UART0_RTS/LPTMR1_ALT144
PTC6/ADC0_SE1/CMP2_IN1/UART0_CTS/QTMR0_TMR1/PDB0_EXTRG45
PTC7/ADC0_SE2/CMP2_IN2/UART0_TX/XBAR0_OUT246
PTD0/LLWU_P11/CMP0_IN0/UART0_RX/XBAR0_IN247
PTD1/UART1_TX/SPI0_PCS0/XBAR0_OUT3/QTMR0_TMR348
PTD2/LLWU_P10/CMP0_IN1/UART1_RX/SPI0_SCK/XBAR0_IN349
PTD3/UART1_CTS/SPI0_MOSI/LPTMR1_ALT250
PTD4/LLWU_P9/ADC0_SE3/UART1_RTS/SPI0_MISO/LPTMR1_ALT351
PTD5/ADC0_SE4A/LPTMR0_ALT3/QTMR0_TMR0/UART3_CTS52
PTD6/LLWU_P8/ADC0_SE5A/LPTMR0_ALT2/CMP1_OUT/UART3_RTS53
PTD7/LLWU_P7/CMP0_IN4/I2C0_SCL/XBAR0_IN4/UART3_RX54
PTE0/I2C0_SDA/XBAR0_OUT4/UART3_TX/CLKOUT55
PTE1/RESET56
PTE2/EXTAL0/EWM_IN/XBAR0_IN6/I2C1_SDA57
PTE4/LPTMR0_ALT1/UART2_CTS/EWM_IN63
PTE5/LLWU_P6/QTMR0_TMR3/UART2_RTS/EWM_OUT64
PTE6/LLWU_P5/CMP0_IN2/XBAR0_IN5/UART2_RX/I2C0_SCL/SWD_DIO65
PTE7/ADC0_SE6A/XBAR0_OUT5/UART2_TX/I2C0_SDA/SWD_CLK66
PTF0/LLWU_P4/ADC0_SE7A/CMP2_IN3/RTC_CLKOUT/QTMR0_TMR2/CMP0_OUT67
PTF1/LCD_P0/ADC0_SE8/CMP2_IN4/QTMR0_TMR0/XBAR0_OUT668
PTF2/LCD_P1/ADC0_SE9/CMP2_IN5/CMP1_OUT/RTC_CLKOUT69
PTF3/LLWU_P20/LCD_P2/SPI1_PCS0/LPTMR0_ALT2/UART0_RX70
PTF4/LCD_P3/SPI1_SCK/LPTMR0_ALT1/UART0_TX71
PTF5/LCD_P4/SPI1_MISO/I2C1_SCL72
PTF6/LLWU_P3/LCD_P5/SPI1_MOSI/I2C1_SDA73
PTF7/LCD_P6/QTMR0_TMR2/CLKOUT/CMP2_OUT74
PTG0/LCD_P7/QTMR0_TMR1/LPTMR0_ALT375
PTG1/LLWU_P2/LCD_P8/ADC0_SE10/LPTMR0_ALT176
PTG2/LLWU_P1/LCD_P9/ADC0_SE11/SPI0_PCS077
PTG3/LCD_P10/SPI0_SCK/I2C0_SCL78
PTG4/LCD_P11/SPI0_MOSI/I2C0_SDA79
PTG5/LCD_P12/SPI0_MISO/LPTMR0_ALT280
PTG6/LLWU_P0/LCD_P13/LPTMR0_ALT381
PTG7/LCD_P14/LPTMR1_ALT182
PTH0/LCD_P15/LPUART0_CTS83
PTH1/LCD_P16/LPUART0_RTS84
PTH2/LCD_P17/LPUART0_RX85
PTH3/LCD_P18/LPUART0_TX86
PTH4/LCD_P19/LPTMR1_ALT287
PTH5/LCD_P20/LPTMR1_ALT388
PTH6/UART1_CTS/SPI1_PCS0/XBAR0_IN789
PTH7/UART1_RTS/SPI1_SCK/XBAR0_OUT790
PTI0/LLWU_P21/CMP0_IN5/UART1_RX/XBAR0_IN8/SPI1_MISO/SPI1_MOSI91
PTI1/UART1_TX/XBAR0_OUT8/SPI1_MOSI/SPI1_MISO92
PTI2/LLWU_P22/LCD_P21/LPUART0_RX93
PTI3/LCD_P22/LPUART0_TX/CMP2_OUT94
VDD
110
VDD
262
VSS1
11
VSS2
27
VSS3
59
VSS4
95
AFE_
VDD
A31
AFE_
VSSA
32
VDD
A61
VSSA
60
VREF
H37
VREF
L38
VBAT
24
VREF41
VCAP
1/LC
D_P
63/P
TM3
100
VCAP
2/LC
D_P
62/P
TM2
99
VLL1
/LC
D_P
61/P
TM1
98
VLL2
/LC
D_P
60/P
TM0
97
VLL3
96
XTAL3225
EXTAL3226
TAMPER030
TAMPER129
TAMPER228
AFE_SDADP033
AFE_SDADM034
AFE_SDADP135
AFE_SDADM136
AFE_SDADP2/CMP1_IN239
AFE_SDADM2/CMP1_IN340
AFE_SDADP3/CMP1_IN442
AFE_SDADM3/CMP1_IN543
PTE3/XTAL/EWMOUT/AFE_CLK/I2CL_SCL58
TAMP_TERM (Pg4)
VDD
RLY_PWR
SDA_MAG(Pg4)
C130.1uF
MAINS_ON(Pg5)
UART0_RXD(Pg4)
SDADP0 (Pg3)
LPUART0_RX(Pg4)
SPI_CK(Pg4)
VLL2
VREFH
TAMP_COV (Pg4)
Y_PH_AD1(Pg3)
SWD_CLK
LCD_3(Pg4)
Figure 24. Schematic diagram of the metering board - MCU
NXP SemiconductorsMetering board electronics
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 29 / 42
R118
470K
R43 220
L24
1000OHM
1 2
C260.033uF
R48 220
C310.033uF
B_PH(Pg5)
R113
470K
R1326.8
VREF(Pg2)
R27 220
VREF_CTRL (Pg2,3)
L8
1000OHM
1 2
R121
470K
R47 220
C280.033uF
Y_PH(Pg5)
R21810.0K
R1392.20K
R_VREF/2
N_CT1
R112
470K
C270.047UF
SDADM0 (Pg2)
R_PH(Pg5)
SDADM2 (Pg2)
R117
470K
Voltage inputs
R_CT2
R1366.8
B_CT1
VREF_CTRL(Pg2,3)
L5
1000OHM
1 2
L9
1000OHM
1 2
R1346.8
L7
1000OHM
1 2
Y_VR
EF/2
SDADP0 (Pg2)
SDADP2 (Pg2)
R_CT1
R124
470K
R52 220
Y_CT1
R22 220B_PH_AD2 (Pg2)
C320.033uF
R1336.8
R32 220
R42 220
SDADM3 (Pg2)
SDADM1 (Pg2)
L13
1000OHM
1 2
R1316.8
R116
470K
C380.1UF
L6
1000OHM
1 2
Current inputs
R111
470K
Vout= 0.495 @ 300VAC
SDADP3 (Pg2)
SDADP1 (Pg2)
Note: R218 provided as an option for Current sense through Shunt. DNP for CT.
Y_PH_AD1 (Pg2)
R5410K
L14
1000OHM
1 2N_CT2
R123
470K
VCC
C330.033uF
R1306.8
R1412.20K
B_VREF/2
C290.033uF
C570.1UF
Y_VREF/2
R115
470K
B_VR
EF/2
C340.033uF
L10
1000OHM
1 2
L11
1000OHM
1 2
B_CT2
U28
LMV324IDR
OUT1
1IN-2
1IN+3
VCC+4
2IN+5
2IN-6
2OUT7
3OUT83IN-93IN+10GND114IN+124IN- 134OUT14
R23 220
C56
0.1UF
R119
470K
R33 220
R5610K
VREF_CTRL(Pg2,3)
Vref/2
C580.1UF
Y_CT2
C300.047UF
Drawing Title:
Size Document Number Rev
Date: Sheet of
Page Title:
Designer:
Drawn by:
Approved:
Microcontroller Solutions Group6501 William Cannon Drive WestAustin, TX 78735-8598
This document contains information proprietary to NXP and shall not be used for engineering design, procurement or manufacture in whole or in part without the express written permission of NXP Semiconductors.
Classification:NXP SEMICONDUCTORS©
<Doc> 1.1
PKM35Z512VLL7_3PHSM
C
Wednesday, September 29, 2021
02_Analog
Banwari lal
Kamil & Biswanath
Banwari lal
3 5
<PUBI><FIUO><FCP>
N_SHUNT
R37 220
R122
470K
R1356.8
R1402.20K
R_PH_AD0 (Pg2)
CT=2500T
R_V
REF
/2
L12
1000OHM
1 2
C250.033uF
C240.047UF
L4
1000OHM
1 2
C390.1UF
C550.1UF
R1296.8
Figure 25. Schematic diagram of the metering board - Analog sensing
NXP SemiconductorsMetering board electronics
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 30 / 42
PC_RXD(Pg4)
C66
0.1UF
R66
10.0K
PC_VCC
LCD_22(Pg2)
UP_SCROLL (Pg2,5)
PC_VCC
R69100K
VDD
LCD_20(Pg2)
LCD_9(Pg2)
J9
HDR 1X2 TH
12
SPI_MISO(Pg2)
TXD(Pg2)
RF_RXD (Pg2)
DS1
HSA26785
COM11
COM22
COM33
COM44
COM55
COM66
COM77
COM88
T1/T2/T3/T4/T5/T6/T7/T89
T10/T11/T12/T13/T14/T15/T16/T1710
COL2/1D/1E/1C/1G/1F/1B/1A11
COL1/2D/2E/2C/2G/2F/2B/2A12
DP1/3D/3E/3C/3G/3F/3B/3A13
DP2/4D/4E/4C/4G/4F/4B/4A14
DP3/5D/5E/5C/5G/5F/5B/5A15
DP4/6D/6E/6C/6G/6F/6B/6A16
DP5/7D/7E/7C/7G/7F/7B/7A17
S7/8D/8E/8C/8G/8F/8B/8A18
T26/9D/9E/9C/9G/9F/9B/9A19
S9/10D/10E/10C/10G/10F/10B/10A20
T27/T25/T23/T22/T24/T21/T20/T1921
S8/S10/S11/S12/S13/S14/S15/S1622
S1/S6/S5/S4/S3/S2/T18/T923
I2C1_SCL(Pg2)
LCD_17(Pg2)
LCD_13(Pg2)
C620.1UF
MEMORY
VBAT_AUX
NIC CARD INTERFACE
R892.2K
U15
FOD817A
1
23
4
R1431K
TAMP_RF(Pg2)
LCD_21(Pg2)
LCD_10(Pg2)
SPI_CS(Pg2)
R2221.0M
kWh_LED (Pg2)
VCC
NIC_PC (Pg2)
R231 0
VDD
R64470K
R228 0
LCD_18(Pg2)
LCD_14(Pg2)
R62 1.5K
D331N4148
AC
Q4TEFT4300
21
C44
0.1UF
SW5
PB_SWITCH
1
2
3
6
5
4
VDD
PC_TXD(Pg4)
LCD_11(Pg2)
LCD_15(Pg2)
VDD
PC_TXD (Pg4)
I2C1_SDA(Pg2)
J6
HDR_2X5
1 23 4
657 89 10
J2
HDR_1X4
1234
BAT54C
D38
3
1
2
D14
L-53LID
A C
IS25LQ040B-JNLE
U17
CE1
SO/IO12
WP/IO23
GN
D4
SI/IO05
SCK6
HOLD/IO37
VCC
8
R571.0K
C69
0.1UF
R230 0
RFV
RF Open Tamper
VDD
LCD_12(Pg2)
Cover Open Tamper
SPI_MOSI(Pg2)
R63
10.0K
VDD
LCD_0(Pg2)
VDD
R87 1.0K
R232 0
R65470K
LCD
VDD
R14710.0K
D34
1N4148
AC
+ C5310UF
D62 BAT54HT1
DNP
A C
RFV
VCC
Terminal Open Tamper
Note: 1. When Top cover closed2-3 and 5-4 are shorted.2. When Top cover open2-1 and 5-6 are shorted.
U16
FOD817A
1
2 3
4
UART0_TXD(Pg2)
RF_TXD (Pg2)
Cover open and switches
C65
0.1UF
JP8
HDR 1X6
123456
VDDVDD
SPI_MOSI(Pg2)
LCD_6(Pg2)
VDD
R60510
VDD_SW
R61 1.5K
D12
TSAL4400
AC
RF_RTS (Pg2)
SPI_MISO(Pg2)
R145
10.0K
LCD_5(Pg2)
C420.1UF
VDD
J7
HDR_2X5
1 23 4
657 89 10
D61 BAT54HT1
DNP
A C
LCD_4(Pg2)
LCD_7(Pg2)
R226 0
LCD_16(Pg2)
R144 1.5K
VDD
R156 100K
C70
0.1UF
LCD_3(Pg2)
C43
0.1UF
VDDPush Button Switch
D63 BAT54HT1
DNP
A C
Drawing Title:
Size Document Number Rev
Date: Sheet of
Page Title:
Designer:
Drawn by:
Approved:
Microcontroller Solutions Group6501 William Cannon Drive WestAustin, TX 78735-8598
This document contains information proprietary to NXP and shall not be used for engineering design, procurement or manufacture in whole or in part without the express written permission of NXP Semiconductors.
Classification:NXP SEMICONDUCTORS©
<Doc> 1.1
PKM35Z512VLL7_3PHSM
C
Tuesday, September 28, 2021
03_Digital
Banwari lal
Kamil & Biswanath
Banwari lal
4 5
<PUBI><FIUO><FCP>
M24M02-DR
U18
DU_11
DU_22E2
3
VSS
4
SDA5
SCL6
WC7
VCC
8
LCD_2(Pg2)
SDA_MAG (Pg2)
VDD
SW2
PTS645
12
34
R146
10.0KLCD_1(Pg2)
GPIO_NC2(Pg4)
SPI_CK(Pg2)
C640.1UF
TLV493D-A1B6
U20
SCL/INT1
SDA/ADDR6
VDD
4G
ND
_12
GN
D_2
3
GN
D_3
5
VCC
RF_CTS (Pg2)
R227 0
SPI_CS(Pg2)
RS232 COMM
TAMP_COV(Pg2)
VBAT_AUX
RXD(Pg2)
VCC
LED outputs
VCC
VDD
GPIO_NC1(Pg4)SPI_CK(Pg2)
R1421.50K
SW4
PB_SWITCH
1
2
3
6
5
4
LPUART0_TX(Pg4)
kVArh_LED (Pg2)
U19
AH180-WG
VDD1
GND2
OUT3
D11
L-53LID
A C
U5
AH180-WG
VDD1
GND2
OUT3
C410.1UF
DOWN_SCROLL (Pg2)
TAMP_MAG (Pg2)
R1571.0M
UART0_RXD(Pg2)
VDD
R701.0M
Push Button Switch
SCL_MAG (Pg2)
RTC_BAT
SW1PTS645
12
34
R229 0
Magnetic Field Tamper sensor
LCD_19(Pg2)
TAMP_TERM(Pg2)
LCD_8(Pg2)
LPUART0_RX(Pg4)
D15
L-53LID
A C
PC_RXD (Pg4)
IR interface
VDD
VBAT_AUX
SW3
PB_SWITCH
1
2
3
6
5
4
Figure 26. Schematic diagram of the metering board - user interface
NXP SemiconductorsMetering board electronics
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 31 / 42
C1000.22uF
Q16PMV100XPEAR
1
2 3
Drawing Title:
Size Document Number Rev
Date: Sheet of
Page Title:
Designer:
Drawn by:
Approved:
Microcontroller Solutions Group6501 William Cannon Drive WestAustin, TX 78735-8598
This document contains information proprietary to NXP and shall not be used for engineering design, procurement or manufacture in whole or in part without the express written permission of NXP Semiconductors.
Classification:NXP SEMICONDUCTORS©
<Doc> 1.1
PKM35Z512VLL7_3PHSM
C
Wednesday, September 29, 2021
04_PWR Supply
Banwari lal
Kamil & Biswanath
Banwari lal
5 5
<PUBI><FIUO><FCP>
C941000PF
+ C7633uF
C950.022UF
+C851000uF
D461N4007
AC
D501N4007
AC
BT2
ER14250-VB
12
3
+C97
1000uF
L19 1.2mH
1 2
C93
0.1U
F
R235
0 DNP
BAT54C
D37
3
1
2
R18422
C752200PF
R19810K
RTC_BAT
C90
0.1U
F
R202
47
R187 22
VBAT_AUX
R_PH
DNP
C83
2200
PF
R153100K
R180
470K
Y_PH1
DNP
D52
1N4007A C
C681.0UF
B_PH2
DNP
RTC BATTERY POWER
Q17
BC817-40LT1G
23
1
In absence of Mains, Battery supply not required everytime. Battery supply required for MCU wakeup by UP_SCROLL push button or cover open.
MAINS_ON (Pg2)
+C9210uF
R15218K
TVS7
CD
DFN
2-T3
.3LC
12
D49
1N4007
A C
RFV
LATCH(Pg4)
R1911.0K
VBAT_AUX
R196 0
L25 1.2mH1 2
R18
83.
3K
C96 1000pF
T1
EE20
5
3
4
1 67
9
10
82
NEUT
DNP
R190470
BAT54C
D1
3
1
2
R2000
DNP
R211
47
3 PHASE SMPS POWER SUPPLY
R183470K
BAT54CD57
3
1
2
+C77
33uF
+C86
470uF
D45
MURS360T3G
A C
VDD
VDD_SW
D54 US1M
AC
C88
0.1U
F
R199
10K
C91
0.1U
F
R225
B72210S2511K101
12
R213 2.7K
D481N4007
AC
R19318K
U23VIPER267KDTR
GN
D1
NC_12
NC_23
NA4
VDD
5
NC_36
FB7
COMP8
NC_49
NC_510
NC_611
NC_712
DRAIN_113
DRAIN_214
DRAIN_315
DRAIN_416
+C80
10UF
U22
ST732M36RGND
1
VIN2
VOUT3
NC14
NC25
R1921.0K
R_PH(Pg3)
L1
1000OHM
12
R223B72210S2511K101
12
R201220K
R210 10 OHM
R204
47
+-
BT1
CR2032-PEN3
13 2
D53 1N4007
AC
R182470K
R151 10K
VDDL21
1000OHM
1 2
Y_PH(Pg3)
U27TL431AIDBZR
1 3
2
D56 MURS120T3A C
C89
0.1U
F
C820.047UF
D55US1M
AC
R174100k
UP_SCROLL(Pg4)
R102
0
R212 2.7K
D47
1N4007
A C
D51
1N4007
A CB_PH(Pg3)
C81
0.1U
F
RLY_PWR
+C87
470uF
D60
BAT54HT1
A C
U25
TLV809K33DBVR
RES
ET2
VDD
3
GN
D1
RLY_PWR
R209 10 OHM
R203
47R181
470K
Aux Battery Circuit
U24
FOD817A
1
23
4 R195
10K
DNP
C50.1uF
R19422K
R189
10K
R224
B72210S2511K101
12
VCC
L23
3.3uH
1 2
Figure 27. Schematic diagram of the metering board - power supply
NXP SemiconductorsMetering board electronics
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 32 / 42
GND
GND
SIM2
MOLEX-1042240820
sVCC1 RST2 CLK3
GND5NC6DATA7S1
4S2
899
1010
1111
1212
S_D
AT
R11K
+C20
100uf/25V
DCD
GP_TX
+C1922uF,25V
1
2
GND
5V
GN
D
MR
ST
C2
0.1u
f
C4
33pf
WM620/N52 Module - Antenna - USB
R13 100
L4
27nH
GND
GND
S_RST
GND
VMO
D
CON2
USB
12345
V_BUS
J2JMP
GNDS_VCC
GND
S_VC
C
GND
S_DET
SIM Interface
LED1LED
12
+C1810uF,25V
1
2
L227nH
+C16
10uf/25V
GND
GN
D
MC
UVC
C
C6
0.1u
f
GND
ANT
SuperCap
J5 JMP
C10
0.1u
f
RIN
G
C5
0.1u
f
V1_8
V
MCURX
UFL1MM9329-2700
1 2
34
C9
33pf
L52.2uH, 3A
J6 JMP
S_DAT
S_VCC
MOD1
WM620
GND1
NC2
NC3
NC4
NC5
NC6
NC7
NC8
NC9
NC10
NC11
GND12
UIM
_VC
C13
UIM
_RST
14
UIM
_DAT
A15
UIM
_CLK
16
GN
D17
USB
D+
18
USB
D-
19
V_BU
S20
GN
D21
VBAT
122
VBAT
223
GN
D24
RES
ET25
V_M
SME_
1.8V
26
V_M
SMP_
2.6V
27
EAR
_1P
28
EAR
_1N
29
MIC
_1N
30
MIC
_1P
31
ANT44
GND43
NC42
NC41
NC40
NC39
NC38
NC37
SPKR_N36
SPKR_P35
GND34
MIC_N33
NC
62
GN
D61
SLEE
P60
DC
D59
NC
58
NC
57
NC
56
TXD
55
RXD
54
RTS
53
CTS
52
RN
G51
GN
D50
HKA
INO
49
SIG
_LED
48
VCIO
N47
ON
_OFF
46
MIC2_P32
GN
D45
DC
D
MRST
MCUTX
J1JMP
SIG_LED
VMOD
C12
33pf
S_R
ST
R114K7
V1_8V
GN
D
S_VCC
GN
D
VMOD
D2PESD5V0S1BA
L127nH
S_DAT
GND
GN
D
S_RST
MCURX
V1_8
V
D4STPS3H100U
5V
C3
1nf
D3
PESD5V0S1BA
SIG
_LED
J3 JMP
R7560K
R3
10K
MCUTX
S_CLK
SDS
Q1BC817
23
1
GND
S_DAT
R104K7
USB
_D-
R15
DNP
R1210K
J4JMP
C13
33pf
R5
10K
SIG
_LED
+C1
470u
F/10
V
MC
UVC
C
N51 Module Control
GND
V_BUS
S_VCC
GND
R910K
GP_
RX
+C17
100uf/25V
R16
0R
GND
+C15
10uF,25V
1
2
USB_D+
MCUVCC
S_VCC
C11
33pf
D6
PMEG
3030
EP12
V1_8V
FRC2
FRC10
1 23 45 6
879 10
S_C
LK
R21K5
GND
CON1
PCB ANT
12
GND
S_CLK
V_BU
S
MCU Interface
J7JMP
Arrow Electronics India Pvt. Ltd.,
V1_8
V
GP_RX
R41K
+C235F/2.7V
SIM1
MOLEX-475532001sVCC
1 RST2 CLK3
GND5NC6DATA7S1
4S2
899
1010
S_RST
SDS
GND
VMO
D
Title
Size Document Number Rev
Date: Sheet of
1 1.0
Network Interface Card
1 1Tuesday, February 11, 2020
GND
EN
D1
DALC208 / BZA408B
IO11
V2
IO23
IO34GND5IO46
GND
R8
10R
C14
0.1u
f
Q2BC817
23
1
GN
DS_CLK
MC
UVC
C
ANT
FRC1
FRC10
1 23 45 6
879 10
TP1TP
USB_D-
S_RST
D5
PMEG
3030
EP1
2
S_CLK
S_DET
S_DETGND
PWR
C21
33pf
C8 33pf
L3
27nH
U2STBB1-Axx
VOU
T1
SW2
2PG
ND
3SW
14
VIN
5EN
6
MO
DE
/ SYN
C7
VIN
A8
GN
D9
FB10
PAD11
R14100K
EN
C22
33pf
USB
_D+
J8JMP
R6
10K
U1ST732M33R
IN2
NC
04
NC
15
OUT3
GN
D1
GND
S_DAT
GP_
TX
PWR
GND
Q3BC817
2 3
1
MCUVCCGND
Figure 28. Schematic diagram of the GPRS expansion board
10 Metering board layoutThree-phase power meter top-side view of the metering board is shown in Figure 29.
NXP SemiconductorsMetering board layout
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 33 / 42
Figure 29. Top-side view of the metering board (not scaled)
NXP SemiconductorsMetering board layout
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 34 / 42
Figure 30. Bottom-side view of the metering board (not scaled)
NXP SemiconductorsMetering board layout
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 35 / 42
Figure 31. Top-side view of the GPRS module board (not scaled)
NXP SemiconductorsMetering board layout
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 36 / 42
Figure 32. Bottom-side view of the GPRS module board (not scaled)
11 Bill of materials of the metering boardElectronics components used to develop three-phase power meter are mentioned in the table below.
Table 6. BOM report of meter PCB
NXP SemiconductorsBill of materials of the metering board
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 37 / 42
Sr. No Quantity Reference Description Value Mfg Name Mfg Part Number1 1 BT1 BATTERY LI-MNO2 2032 3V 210mAh TH CR2032-PEN3 EEMB CR2032-PEN32 1 BT2 BATTERY LITHIUM 1/2AA 3.6V 1200mAh TH ER14250-VB EEMB ER14250-VB
3 9
Y_CT1,R_CT1,N_CT1,B_CT1,Y_CT2,R_CT2,N_CT2,B_CT2,N_SHUNT
TEST POINT PIN 0.062X0.086 TH, NO PART TO ORDER TP N/A N/A
4 4 Y_PH1,B_PH2,R_PH,NEUTTEST POINT PIN 0.062X0.086 TH, NO PART TO ORDER TP N/A N/A
5 11C1,C4,C5,C6,C7,C8,C9,C10,C11,C13,C19 CAP CER 0.1uF 16V 10% X7R AEC-Q200 0402 0.1uF MURATA GCM155R71C104KA55D
6 1 C2 CAP CER 0.01UF 50V 5% X7R 0603 10nF AVX 06035C103JAT2A7 3 C24,C27,C30 CAP CER 0.047UF 50V 10% X7R 0603 0.047UF AVX 06035C473KAT2A
8 8C25,C26,C28,C29,C31,C32,C33,C34
CAP CER 0.033UF 50V 10% X7R AEC-Q200 0402 0.033uF TDK CGA2B3X7R1H333K050BB
9 6 C38,C39,C55,C56,C57,C58 CAP CER 0.1UF 50V 10% X7R 0603 0.1UF
WURTH ELEKTRONIK EISOS GMBH & CO. KG (ELECTRONIC & ELECTROMEHANICAL COMP) 8.85012E+11
10 10C41,C42,C43,C44,C62,C64,C65,C66,C69,C70 CAP CER 0.10UF 25V 10% X7R 0603 0.1UF KEMET C0603C104K3RAC
11 2 C52,C68 CAP CER 1.0UF 10V 10% X7R 0805 1.0UF SMEC MCCB105K2NRTF12 1 C53 CAP ALEL 10UF 16V 20% -- TH RADIAL 10UF PANASONIC ECEA1CKS10013 1 C54 CAP CER 4.7UF 6.3V 20% X5R 0402 4.7uF TDK C1005X5R0J475M14 1 C72 CAP ALEL 100UF 50V 20% -- TH RADIAL 100UF NICHICON UPJ1H101MPD615 1 C75 CAP CER 2200PF 2KV 10% X7R 1812 2200PF TDK C4532X7R3D222K130KA16 2 C76,C77 CAP ALEL 33uF 450V 20% -- RADIAL 33uF NICHICON UVR2W330MHD17 1 C80 CAP ALEL 10uF 35V 20% -- RADIAL 10UF CORNELL DUBILIER SK100M035ST18 6 C81,C88,C89,C90,C91,C93 CAP CER 0.1UF 25V 10% X7R 0805 0.1UF SMEC MCCC104K2NRTF19 1 C82 CAP CER 0.047UF 50V 10% X7R 0805 0.047UF VENKEL COMPANY C0805X7R500-473KNE20 1 C83 CAP CER 2200PF 50V 5% X7R 0805 2200PF SMEC MCCE222J2NRTF
21 2 C85,C97 CAP ALEL 1000uF 25V 20% -- RADIAL 1000uFLELON ELECTRONICS CORP REA102M1ETAF1316
22 2 C86,C87 CAP ALEL 470UF 25V 20% -- RADIAL 470uF PANASONIC EEUFC1E47123 1 C92 CAP ALEL 10UF 16V 20% -- RADIAL 10uF NICHICON UVR1C100MDD24 1 C94 CAP CER 1000PF 50V 5% C0G 0805 1000PF VENKEL COMPANY C0805C0G500-102JNE25 1 C95 CAP CER 0.022UF 50V 10% X7R 0805 0.022UF KEMET C0805C223K5RACTU
26 1 C96CAP CER 1000pF 760VAC (X1) / 500VAC (Y1) 20% Y5U RADIAL 1000pF
VISHAY INTERTECHNOLOGY 440LD10-R
27 1 C100 CAP PLYP 0.22UF 1KV 10% -- RADIAL 0.22uFEPCOS - TDK Electronics B32913B5224K
28 1 DS1 LCD DISPLAY 64Hz 3V TH HSA26785JIAGNXI HOLITECH TECHNOLOGY CO. HSA26785-DYTSP-01
29 4 D1,D37,D38,D57 OBSOLETE USE 480-77657 BAT54C FAIRCHILD BAT54C30 1 D11 LED RED SGL 2MA TH L-53LID KINGBRIGHT L-53LID
31 1 D12 LED IR SGL 100MA TH TSAL4400VISHAY INTERTECHNOLOGY TSAL4400
32 2 D14,D15 LED RED SGL 2MA TH L-53LID KINGBRIGHT L-53LID33 2 D33,D34 DIODE SS 100V 500MW AXIAL 1N4148 FAIRCHILD 1N4148
34 2 D39,D40 DIODE RECT 1A 1000V SOD-123FL 1N4007FLSMC DIODE SOLUTIONS LLC 1N4007FLTR
35 1 D45 DIODE PWR RECT 3A 600V SMT MURS360T3GON SEMICONDUCTOR MURS360T3G
36 8D46,D47,D48,D49,D50,D51,D52,D53 DIODE RECT 1A 1KV DO41 1N4007 DIODES INC 1N4007-T
37 2 D54,D55 DIODE RECT FAST RECOVERY 1A 1000V SMA US1M DIODES INC US1M-13-F
38 1 D56 DIODE PWR RECT 1A 200V SMB SMT MURS120T3ON SEMICONDUCTOR MURS120T3G
39 1 D60 DIODE SCH 30V 200MA -- SOD323 BAT54HT1ON SEMICONDUCTOR BAT54HT1G
40 3 D61,D62,D63 DIODE SCH 30V 200MA -- SOD323 BAT54HT1ON SEMICONDUCTOR BAT54HT1G
41 1 JP8 HDR 1X6 TH 100MIL SP 330H AU 100L HDR 1X6 SAMTEC TSW-106-07-S-S
42 1 J1 HDR 1X5 TH 100MIL SP 336H SN 118L HDR 1X5GREENCONN CORPORATION GPHA114-0501A01
43 1 J2 HDR 1X4 TH 100MIL SP 336H AU 100L HDR_1X4 SAMTEC TSW-104-07-G-S
44 1 J3 HDR 1X3 TH 2.54MM SP 344H AU 118L HDR 1X3
WURTH ELEKTRONIK EISOS GMBH & CO. KG (ELECTRONIC & ELECTROMEHANICAL COMP) 61300311121
45 2 J6,J7 HDR 2X5 TH 100MIL CTR 330H AU HDR_2X5 SAMTEC TSW-105-08-G-D46 1 J9 HDR 1X2 TH 100MIL SP 339H AU 98L HDR 1X2 TH SAMTEC TSW-102-07-G-S
47 14L1,L4,L5,L6,L7,L8,L9,L10,L11,L12,L13,L14,L21,L24
IND FER BEAD 1000OHM@100MHZ 1.5A 25% 0805 1000OHM TDK MPZ2012S102A
48 2 L19,L25IND PWR 1.2mH@100KHZ 280MA 10% RADIAL 1.2mH COILCRAFT RFB0807-122L
49 1 L23 IND CHK 3.3uH@1KHz 3A 20% 10mOHM TH 3.3uH Prismatic 122001
50 1 Q4 TRAN NPN PHOTO 50MA 70V TH TEFT4300VISHAY INTERTECHNOLOGY TEFT4300
51 1 Q16 TRAN PMOS SW 2.4A 20V AEC-Q101 SOT-23 PMV100XPEAR NEXPERIA PMV100XPEAR
52 1 Q17 TRAN NPN GEN 45V 0.5A SOT-23 BC817-40LT1GON SEMICONDUCTOR BC817-40LT1G
53 2 Q18,Q19 TRAN NMOS 30V 3.7A SOT23 PMV90ENE NEXPERIA PMV90ENER54 6 R1,R63,R66,R145,R146,R147 RES MF 10.0K 1/10W 1% 0603 10.0K YAGEO AMERICA RC0603FR-0710KL
55 11R22,R23,R27,R32,R33,R37,R42,R43,R47,R48,R52 RES MF 220 OHM 1/10W 1% 0603 220 BOURNS CR0603-FX-2200ELF
NXP SemiconductorsBill of materials of the metering board
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 38 / 42
Sr. No Quantity Reference Description Value Mfg Name Mfg Part Number
56 6 R54,R56,R151,R189,R198,R199 RES MF 10K 1/8W 5% 0805 10K VENKEL COMPANY CR0805-8W-103JT57 1 R57 RES MF 1.0K 1/8W 5% AEC-Q200 0805 1.0K ROHM MCR10EZPJ10258 1 R60 RES MF 510 OHM 1/10W 1% 0805 510 SMEC RC73A2A5100FTF59 3 R61,R62,R144 RES MF 1.5K 1/8W 1% 0805 1.5K BOURNS CR0805-FX-1501ELF60 2 R64,R65 RES MF 470K 1/10W 1% 0603 470K BOURNS CR0603-FX-4703ELF61 1 R69 RES MF 100K 1/10W 1% 0603 100K BOURNS CR0603-FX-1003ELF
62 3 R70,R157,R222 RES MF 1.0M 1/10W 1% 0603 1.0M
WALSIN TECHNOLOGY CORP. WR06X1004FTL
63 1 R87 RES MF 1.0K 1/10W 1% 0805 1.0K MULTICOMP MC 0.1W 0805 1% 1K64 1 R89 RES MF 2.2K 1/8W 1% 0805 2.2K PANASONIC ERJ-6ENF2201V65 4 R102,R230,R231,R232 RES MF ZERO OHM 1/10W -- 0603 0 YAGEO AMERICA RC0603FR-070RL
66 16
R111,R112,R113,R115,R116,R117,R118,R119,R121,R122,R123,R124,R180,R181,R182,R183 RES MF 470K 1/4W 5% 1206 470K VENKEL COMPANY CR1206-4W-474JT
67 8R129,R130,R131,R132,R133,R134,R135,R136 RES MF 6.8 OHM 1/8W 1% AEC-Q200 0603 6.8 KOA SPEER RK73H1JTTD6R80F
68 3 R139,R140,R141 RES MF 2.20K 1/10W 1% 0603 2.20K BOURNS CR0603-FX-2201ELF
69 1 R142 RES MF 1.50K 1/10W 1% 0603 1.50KVISHAY INTERTECHNOLOGY CRCW06031K50FKEA
70 1 R143 RES 1.0K OHM 1/10W 5% 0603 1K YAGEO AMERICA RC0603JR-071KL
71 2 R152,R193 RES MF 18.0K 1/8W 1% 0805 18KVISHAY INTERTECHNOLOGY CRCW080518K0FKEA
72 2 R153,R156 RES MF 100K 1/8W 1% 0805 100K VENKEL COMPANY CR0805-8W-1003FSNT73 2 R159,R161 RES MF 47.0K 1/10W 1% 0805 47.0K SMEC RC73A2A4702FTF
74 2 R160,R162 RES MF 1.00K 1/8W 1% ACE-Q200 0805 1.0KVISHAY INTERTECHNOLOGY CRCW08051K00FKEA
75 1 R174 RES MF 100k 1/2W 5% AEC-Q200 1210 100k PANASONIC ERJ-14YJ104U76 1 R184 RES MF 22 OHM 1/4W 5% 1206 22 BOURNS CR1206-JW-220ELF77 1 R187 RES MF 22 OHM 1/8W 5% 0805 22 BOURNS CR0805-JW-220ELF78 1 R188 RES MF 3.3K 1/8W 5% 0805 3.3K BOURNS CR0805-JW-332ELF79 1 R190 RES MF 470 OHM 1/8W 1% 0805 470 BOURNS CR0805-FX-4700ELF80 2 R191,R192 RES MF 1.0K 1/4W 5% 1206 1.0K BOURNS CR1206-JW-102ELF
81 1 R194 RES MF 22K 1/4W 1% AEC-Q200 0805 22KKOA Speer Electronics, Inc. SG73S2ATTD2202F
82 1 R195 RES MF 10K 1/8W 5% 0805 10K VENKEL COMPANY CR0805-8W-103JT83 1 R196 RES MF ZERO 1/8W AEC-Q200 0805 0 ROHM MCR10EZPJ00084 1 R200 RES MF ZERO 1/8W AEC-Q200 0805 0 ROHM MCR10EZPJ00085 1 R201 RES TF 220K 1/8W 5% 0805 220K PANASONIC ERJ6GEYJ224V86 4 R202,R203,R204,R211 RES WW 47 OHM 3W 5% AXL 47 YAGEO AMERICA PNP300JR-73-47R87 1 R208 RES MF ZERO OHM 1/16W 5% 0402 0 YAGEO AMERICA RC0402JR-070RL88 2 R209,R210 RES MF 10 OHM 1/4W 1% 1206 10 OHM YAGEO RC1206FR-0710RL89 2 R212,R213 RES MF 2.7K 1/4W 1% 1206 2.7K YAGEO AMERICA RC1206FR-072K7L90 1 R218 RES MF 10.0K 1/8W 1% 0805 10.0K VENKEL COMPANY CR0805-8W-1002FT91 3 R223,R224,R225 VARISTOR 510VRMS 0.4W 10% TH B72210S2511K101 TDK B72210S2511K10192 4 R226,R227,R228,R229 RES MF ZERO OHM 1/10W -- 0402 0 PANASONIC ERJ-2GE0R00X
93 1 R233 RES MF 100K 1/16W 1% 0402 100KVISHAY INTERTECHNOLOGY CRCW0402100KFKEDC
94 1 R234 RES MF 10K 1/16W 1% 0402 10K VISHAY CRCW040210K0FKEDC95 1 R235 RES MF ZERO OHM 1/10W -- 0603 0 YAGEO AMERICA RC0603FR-070RL
96 2 SW1,SW2OBSOLETE SW SPST MOM NO PB 12V 50MA SMT PTS645 ITT CANNON PTS645SL50SMTR LFS
97 3 SW3,SW4,SW5 SW DPDT PB 2A 500V TH PB_SWITCH C&K COMPONENTS PS221605FNS98 3 TP1,TP2,TP3 TEST POINT PAD .035 SMT, no part to order TP_35MIL99 5 TVS1,TVS2,TVS3,TVS6,TVS7 OBSOLETE DIODE TVS BIDIR -- 3.3V SMD CDDFN2-T3.3LC BOURNS CDDFN2-T3.3LC
100 1 T1 BOBBIN EE20 HORIZONTAL TH EE20
WURTH ELEKTRONIK EISOS GMBH & CO. KG (ELECTRONIC & ELECTROMEHANICAL COMP) 070-4989
101 2 U5,U19IC SW SENSOR OMNIPOLAR HALL-EFFECT 2.5-5.5V SC59 AH180-WG DIODES INC AH180-WG-7
102 3 U15,U16,U24 TRAN NPN PHOTO 50MA 70V DIP4 FOD817A ON Semiconductor FOD817A
103 1 U17IC MEM FLASH 4MB SPI 104MHz 2.7-3.6V SOIC8 IS25LQ040B-JNLE ISSI IS25LQ040B-JNLE
104 1 U18IC MEM EEPROM 2Mb I2C 1MHZ 1.8-5.5V SO8 M24M02-DR
ST MICROELECTRONICS M24M02-DRMN6TP
105 1 U20 IC MAGNETIC SENSOR 3D 2.7-3.5V TSOP6-6 TLV493D-A1B6Infineon Technologies TLV493DA1B6HTSA2
106 1 U21IC MCU FLASH 512KB SRAM 75MHZ 1.71-3.6V LQFP100 MKM35Z512VLL7
NXP SEMICONDUCTORS MKM35Z512VLL7
107 1 U22 IC VREG LDO 3.6V 300mA 2.5-28V SOT23-5 ST732M36R
ST MICROELECTRONICS ST732M36R
108 1 U23IC HIGH VOLTAGE CONVERTER 1050V 60kHz 11.5-23.5V SO16 VIPER267KDTR
ST MICROELECTRONICS VIPER267KDTR
109 1 U25 IC VOLTAGE MONITOR 2-6V SOT-23-3 TLV809K33DBVRTEXAS INSTRUMENTS TLV809K33DBVR
110 1 U27IC VREG SHUNT 100MA ADJ 36V 1% AEC-Q100 SOT23-3 TL431AIDBZR NEXPERIA TL431AIDBZR,215
111 1 U28 IC LIN OPAMP QUAD 2.7-5.5V SOIC14 LMV324IDR Texas Instruments LMV324IDR112 1 Y1 XTAL 32.768KHZ RSN -- TH AB26T-32.768KHZ ABRACON CORP AB26T-32.768KHZ
NXP SemiconductorsBill of materials of the metering board
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 39 / 42
12 Bill of materials of the GPRS boardElectronics components used to develop GPRS module are mentioned in the table below.
Table 7. BOM report of GPRS moduleItem Qty Reference Description Part Number Manufacturer Value
1 1 CON1 PCB PAD NA NA NA2 1 CON2 Headers & Wire Housings BERGSTIK 10119333-103A05LF Amphenol FCI BERG STICK3 1 C1 Tantalum Capacitors - Solid SMD 470uF 10volts 10% T495X477K010ATE100 KEMET 470uf/16v4 3 C2,C5,C6 Multilayer Ceramic Capacitors MLCC - SMD/SMT 0.1uF 50V X7R 10% CC0603KRX7R9BB104 YAGEO 0.1uf5 1 C3 Multilayer Ceramic Capacitors MLCC - SMD/SMT 1.0nF 50V X7R 10% CC0603KRX7R9BB102 YAGEO 1nf6 2 C10,C14 Multilayer Ceramic Capacitors MLCC - SMD/SMT 0.1uF 50V X7R 10% CC0402KRX7R9BB104 YAGEO 0.1uf7 3 C11,C12,C13 Multilayer Ceramic Capacitors MLCC - SMD/SMT 33pF 50V NPO 10% CC0402JRNPO8BN330 YAGEO 33pf8 3 C4,C21,C22 Multilayer Ceramic Capacitors MLCC - SMD/SMT 33pF 50V NPO 10% CC0603JRNPO8BN330 YAGEO 33pf9 2 C8,C9 Multilayer Ceramic Capacitors MLCC - SMD/SMT / DNP CC0402JRNPO8BN330/ DNP YAGEO 33pf/DNP
10 3 C15,C18,C16 Multilayer Ceramic Capacitors MLCC - SMD/SMT 10uF 10% 25V YAGEO 10uf11 1 C17 Tantalum Capacitors - Solid SMD 100uF 25volts 20% T495E107M025AHE100 KEMET 100uf12 2 C19,C20 100uf/25v Aluminum case, electrolytic capacitor UVR1E101MED1TD NICHICON 100uf13 1 C23 Supercapacitors / Ultracapacitors 5F 2.7V 505DCN2R7Q illinoiscapacito 5F/2.7V14 1 D1 ESD Suppressors / TVS Diodes DIODE ARRAY TAPE-7 BZA408B,115 / DALC208 Nexperia TVS Diode15 2 D2,D3 ESD Suppressors / TVS Diodes TRANS BIPOLAR PESD5V0S1BAF Nexperia PESD5V0S1BAF16 1 D4 Schottky Diodes & Rectifiers 100V Vrrm 3A IF Schottky Barrier STPS3H100U STMicroelectronics STPS3H100U17 2 D5,D6 Schottky Diodes & Rectifiers SCHOTTKY RECT 30V 3A PMEG3030EP,115 Nexperia PMEG3030EP,11518 2 FRC1,FRC2 Headers & Wire Housings BERGSTIK 10119333-103A05LF Amphenol FCI BERG STICK19 8 J1,J2,J3,J4,J5,J6,J7,J8 PCB PAD RC0402FR-070L YAGEO 0R20 1 LED1 Standard LEDs - SMD WL-SMCW SMDMono TpVw Waterclr 0805 Red 150080RS75000 / QTLP630C-2TR Wurth Elektronik / EVERLIGHT LED21 4 L1,L2,L3,L4 Fixed Inductors WE-KI 0402 27nH 400mA DCR=298mOhms5% 744765127A / CW100505-27NJ / DNP Wurth Elektronik / BOURNS 27nH22 1 L5 Fixed Inductors 2.2 ohms 20% High Temp AEC-Q200 IHLP1212BZEV2R2M5A VISHAY 2.2uH23 1 MOD1 WM620 Module WM620 Neoway Technology WM62024 3 Q1,Q2,Q3 Bipolar Transistors - BJT BC817K-40H/SOT23/TO-236AB BC817K-40HVL Nexperia BC81725 2 R1,R4 Thick Film Resistor RC0603FR-071KL YAGEO 1K26 1 R2 Thick Film Resistor RC0603FR-071K5L YAGEO 1K527 2 R3,R5 Thick Film Resistor RC0402FR-0710KL YAGEO 10K28 3 R6,R9,R12 Thick Film Resistor RC0603FR-0710KL YAGEO 10K29 2 R10,R11 Thick Film Resistor RC0603FR-074K7L YAGEO 4K730 1 R7 Thick Film Resistor RC0603FR-07560KL YAGEO 560k31 1 R14 Thick Film Resistor RC0603FR-07100KL YAGEO 100K32 1 R13 Thick Film Resistor RC0603FR-07100RL YAGEO 100R33 2 R15,R16 Thick Film Resistor RC0603FR-070RL / DNP YAGEO 0R34 1 R8 Thick Film Resistor RC1206FR-0710RL YAGEO 10R35 1 SIM1 Memory Card Connectors ASSY FOR PUSH PUSH 6 PIN SIM CONN. 47553-2001 Molex SIM Holder36 1 SIM2 Memory Card Connectors ASSY FOR PUSH PUSH 6 PIN SIM CONN. 104224-0820 / DNP Molex SIM Holder37 1 TP1 Testpoint NA NA NA38 1 UFL1 RF Connectors / Coaxial Connectors 2/2.55MM STD SMT ULTRA MINI RF JACK 1909763-1 TE Connectivity RF Connector39 1 U1 LDO Voltage Regulators 300mA, 28V low-dropout voltage regulator ST732M28R STMicroelectronics ST732M28R40 1 U2 Switching Voltage Regulators 1A High EFF DC DC 1.5MHz 2.0V to 5.5V STBB1-APUR STMicroelectronics STBB1-APUR
13 References1. Single Point Meter Calibration process (document AN12827)
2. FFT-Based Algorithm for Metering Applications (document AN4255)
3. Using FFT on the Sigma-Delta ADCs (document AN4847)
4. Filter-Based Algorithm for Metering Applications (document AN4265)
5. MKM35Z512 SDK Software Drivers (available at https://mcuxpresso.nxp.com)
6. FreeMASTER Data Visualization and Calibration Software (available at www.nxp.com/FreeMASTER)
7. KM35Z512 based one-Phase Smart Power Meter Reference Design (document AN12837 )
8. Kinetis-M Three-Phase Power Meter Reference Design (document DRM147)
9. Low-Power Real-Time Algorithm for Metering Applications (document AN13259)
14 Revision historyThe following table lists the substantive changes done to this document since the initial release.
NXP SemiconductorsBill of materials of the GPRS board
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 40 / 42
Table 5. Revision history
Revision number Date Substantive changes
0 25 November 2021 Initial release
NXP SemiconductorsRevision history
KM35Z512 based Three-Phase Smart Power Meter Reference Design, Rev. 0, 25 November 2021Application Note 41 / 42
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Date of release: 25 November 2021Document identifier: AN13338