I Evaluation Motor Board - NXP Semiconductors · User’s Manual Evaluation Motor Board 2 Evaluation Motor Board MOTOROLA Evaluation Motor Board Important Notice to Users While every

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Motorola Embedded Motion Control

EvaluationMotor Board

User’s Manual

For More Information On This Product,

Go to: www.freescale.com

Evaluation Motor Board

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Important Notice to Users

While every effort has been made to ensure the accuracy of all information inthis document, Motorola assumes no liability to any party for any loss ordamage caused by errors or omissions or by statements of any kind in thisdocument, its updates, supplements, or special editions, whether such errors areomissions or statements resulting from negligence, accident, or any other cause.Motorola further assumes no liability arising out of the application or use of anyinformation, product, or system described herein: nor any liability for incidentalor consequential damages arising from the use of this document. Motoroladisclaims all warranties regarding the information contained herein, whetherexpressed, implied, or statutory, including implied warranties ofmerchantability or fitness for a particular purpose. Motorola makes norepresentation that the interconnection of products in the manner describedherein will not infringe on existing or future patent rights, nor do thedescriptions contained herein imply the granting or license to make, use or sellequipment constructed in accordance with this description.

Trademarks

This document includes these trademarks:

Motorola and the Motorola logo are registered trademarksof Motorola, Inc.

Motorola, Inc., is an Equal Opportunity / Affirmative Action Employer.

© Motorola, Inc., 2000; All Rights Reserved

User’s Manual Evaluation Motor Board

2 Evaluation Motor Board MOTOROLA For More Information On This Product,


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User’s Manual — Evaluation Motor Board

List of Sections

Section 1. Introduction and Setup. . . . . . . . . . . . . . . . . .11

Section 2. Operational Description . . . . . . . . . . . . . . . . .17

Section 3. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . .21

Section 4. Schematics and Parts List . . . . . . . . . . . . . . .29

Section 5. Design Considerations . . . . . . . . . . . . . . . . . .39

Evaluation Motor Board User’s Manual

MOTOROLA List of Sections 3 For More Information On This Product,


List of Sections

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4 List of Sections MOTOROLA For More Information On This Product,


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Table of Contents

Section 1. Introduction and Setup

1.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.2 EVM Motor Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.3 About this Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.4 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.5 Setup Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Section 2. Operational Description

2.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.3 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2.4 Motor Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Section 3. Pin Descriptions

3.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.3 Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233.3.1 EVM Motor Board Power Connectors J3 and J4. . . . . . . . . . . . . . 233.3.2 EVM Motor Board 40-Pin Ribbon Connector J1 . . . . . . . . . . . . . 233.3.3 EVM Motor Board Output Connector J2. . . . . . . . . . . . . . . . . . . . 263.3.4 Motor Power Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.3.5 Motor Hall Sensor Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.3.6 Motor Encoder Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273.3.7 Motor Encoder Cable Connectors . . . . . . . . . . . . . . . . . . . . . . . . . 273.3.8 Test Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27


MOTOROLA Table of Contents 5 For More Information On This Product,


Table of Contents

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Section 4. Schematics and Parts List

4.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.2 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.3 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.4 Encoder Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.5 Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Section 5. Design Considerations

5.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.2 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.3 3-Phase H-Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.4 Bus Voltage and Current Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.5 Back EMF Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42


6 Table of Contents MOTOROLA For More Information On This Product,


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List of Figures

Figure Title Page

1-1 Systems’ Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121-2 EVM Motor Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131-3 EVM Motor Board Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3-1 40-Pin Input Connector J1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4-1 Motor EVM Board Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304-2 3-Phase H-Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314-3 Bus Current Feedback. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324-4 Back EMF Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334-5 Brushless dc Motor Connections — Schematic View . . . . . . . . . . . . 344-6 Encoder Connector — Physical View . . . . . . . . . . . . . . . . . . . . . . . . 35

5-1 Phase A Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405-2 Bus Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415-3 Phase C Back EMF Feedback. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42


MOTOROLA List of Figures 7 For More Information On This Product,


List of Figures

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8 List of Figures MOTOROLA For More Information On This Product,


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List of Tables

Table Title Page

2-1 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182-2 Motor Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3-1 Connector J1 Signal Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 233-2 Connector J2 Signal Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 263-3 Motor Hall Sensor Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263-4 Motor Encoder Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273-5 Test Points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4-1 Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36


MOTOROLA List of Tables 9 For More Information On This Product,


List of Tables

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10 List of Tables MOTOROLA For More Information On This Product,


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Section 1. Introduction and Setup

1.1 Contents

1.2 EVM Motor Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.3 About this Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.4 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1.5 Setup Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2 EVM Motor Introduction

Motorola’s evaluation motor board (EVM motor board) is a 12-volt, 4-amppower stage that is an integral part of Motorola’s embedded motion controlseries of development tools. It is supplied in kit number ECMTREVAL, alongwith a small brushless dc motor, an encoder, an encoder cable, a 40-pin ribboncable, and mounting hardware. In combination with one of the embeddedmotion control series control or evaluation boards, it provides a ready-madesoftware development platform for small brushless dc motors. The motor iscapable of being controlled with either Hall sensors, an optical encoder, or withsensorless techniques. An illustration of the systems’ configurations is shown inFigure 1-1. Figure 1-2 is an illustration of the board.

1.3 About this Manual

Key items can be found in the following locations in this manual:

• Setup instructions are found in 1.5 Setup Guide.

• Schematics are found in 4.3 Schematics.

• Pin assignments are shown in Figure 3-1. 40-Pin Input Connector J1,and a pin-by-pin description is contained in 3.3 Signal Descriptions.

• For those interested in the reference design aspects of the board’scircuitry, a description is provided in Section 5. Design Considerations.


MOTOROLA Introduction and Setup 11 For More Information On This Product,


Introduction and Setup

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Figure 1-1. Systems’ Configurations

HC08CONTROLLER

BOARD

EVM MOTORBOARD

MOTOR

WORKSTATION

MMDS08DSPEVM

BOARD

EVM MOTORBOARD

MOTOR

WORKSTATION

b) 56800 DSPa) MC68HC08 MICROCONTROLLER

OPTIONAL FEEDBACKOPTIONAL FEEDBACK


12 Introduction and Setup MOTOROLA For More Information On This Product,


Introduction and SetupAbout this Manual

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Figure 1-2. EVM Motor Board

R307

R30

6

R305

R30

4 R30

3

R302

R301

R22

1

R220

R21

9

R21

8

R21

7R

216

R215

R21

4

R213

R21

2

R21

1

R21

0

R209

R20

8

R20

7

R206

R20

5

R20

4

R20

3

R202

R20

1

R11

1R

110

R10

7

R10

4R

103

R10

2

R1

R10

5

R10

8

C102

+

C103

+

C104

+

R11

3

R11

2

R10

9

R10

6

C10

7

U101

D3 D2

J4

39 40

J1

21

R10

1

U102

+

C105

+

C106

+

U103

C101

+

U3

L1C

108

C10

9

Q103 Q102 Q101

R222

R223

POWER 12V- +

MO

TO

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EVM Motor BoardNo. 00124_02 01/00

R22

4

PHA

SE A

PHA

SE B

PHA

SE C

R225

DCB_POS

GND

Copyright c 2000

+3.3V_A

GNDA

GND

+5V_D

POWER ON

C301

C303

C302+

U301

U302

R226

C3+

D1

C2

J2

U2

J3

U20

1

C203

C20

1

C20

2

C20

4

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5

C206

C4+

C1 +

F1

D4

D10

3

R11

9

D10

4

R11

8

R117

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2

R116R125

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6

R124

D10

5

R12

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122

R120R121

R11

5

D10

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114





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1.4 Warnings

The EVM motor board kit includes a rotating machine and power transistors.Both can reach temperatures hot enough to cause burns. To facilitate safeoperation, 12-volt input power should come from a dc laboratory power supplythat is current limited to no more than 6 amps.

The user should be aware that:

• Before moving scope probes, making connections, etc., it is generallyadvisable to power down the 12-volt supply.

• Operation in lab setups that have grounded tables and/or chairs should beavoided.

• Wearing safety glasses, avoiding ties and jewelry, using shields, andoperation by personnel trained in power electronics lab techniques arealso advisable.




Introduction and SetupSetup Guide

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1.5 Setup GuideSetup and connections for the EVM motor board are straightforward. The EVMmotor board connects to a Motorola embedded motion control series controlboard via a 40-pin ribbon cable. The motor’s power leads plug into outputconnector J2, and its Hall sensors plug into the control board’s Hallsensor/encoder input connector. Figure 1-3 depicts a completed setup.

Follow these steps to set up the board:

1. Mount four standoffs to the EVM motor board at the locations indicatedin Figure 1-3. Standoffs, screws, and washers are included in the kit.This step and step 3 are optional when making connections with DSPcontrol boards such as the DSP56F805EVM. The DSP boards may beplaced flat on a bench, next to the EVM motor board.

2. Plug one end of the 40-pin ribbon cable that is supplied with Motorolaembedded motion control series control boards into input connector J1,located on the right-hand side of the board. The other end of this cablegoes to the control board’s 40-pin output connector.

3. Mount the control board on top of the standoffs with screws and washersfrom the ECMTREVAL kit. This step is optional with DSP controlboards.

4. Plug the free end of the cable connected to input connector J1 into thecontrol board’s 40-pin connector.

5. Connect a 12-Vdc power supply either to connector J3, labeled “Power12V,” or power jack J4. Either one, but not both, may be used. Theseconnectors are located on the front right-hand corner of the board. The12-volt power supply should be rated for at least 4 amps and have itscurrent limit set between 4 and 6 amps.

6. If protection features are desired, set the control board’s overcurrentdetection comparator to 2.8 V and its undervoltage detection comparatorto 1.24 V. These values limit dc bus current to 2.8 amps and turn off drivesignals if bus voltage falls below 6 volts.

7. Apply power to the EVM motor board. The green power-on LED lightswhen power is present. Note that the EVM motor board powers thecontrol board, making only one power supply necessary to run acomplete system.

CAUTION: Since the control board is powered by the EVM motor board, it is imperativethat only one power supply is used.





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Figure 1-3. EVM Motor Board Setup

MOTOR

56800

EVM MOTOR40-PINRIBBON CABLE

STANDOFF

12-VOLTMOTOR SUPPLY

STANDOFF

BOARD

EVALUATION MODULEOR

HC08 CONTROL BOARD

STANDOFFS




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Section 2. Operational Description

2.1 Contents

2.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.3 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2.4 Motor Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.2 Introduction

Motorola’s embedded motion control series EVM motor board is a 12-volt,4-amp, surface-mount power stage that is shipped with an MCG IB23810-H1brushless dc motor. In combination with one of the embedded motion controlseries control boards, it provides a software development platform that allowsalgorithms to be written and tested without the need to design and build a powerstage. It supports algorithms that use Hall sensors, encoder feedback, and backEMF (electromotive force) signals for sensorless control.

The EVM motor board does not have overcurrent protection that is independentof the control board, so some care in its setup and use is required if a lowerimpedance motor is used. With the motor that is supplied in the kit, the poweroutput stage will withstand a full-stall condition without the need forovercurrent protection. Current measuring circuitry is set up for 4 amps fullscale. In a 25οC ambient operation at up to 6 amps continuous RMS outputcurrent is within the board’s thermal limits.

Input connections are made via 40-pin ribbon cable connector J1. Pinassignments for the input connector are shown in Figure 3-1. 40-Pin InputConnector J1. Power connections to the motor are made on output connectorJ2. Phase A, phase B, and phase C are labeled on the board. Power requirementsare met with a single external 12-Vdc, 4-amp power supply. Two connectors,labeled J3 and J4, are provided for the 12-volt power supply. J3 and J4 are


MOTOROLA Operational Description 17 For More Information On This Product,


Operational Description

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located on the front edge of the board. Power is supplied to one or the other, butnot both.

A summary of the information needed to use the EVM motor board follows. Fordesign information, see Section 5. Design Considerations.

2.3 Electrical Characteristics

The electrical characteristics in Table 2-1 apply to operation at 25°C and a12-Vdc power supply voltage.

Table 2-1. Electrical Characteristics

Characteristic Symbol Min Typ Max Units

Power Supply Voltage Vdc 10 12 16 V

Quiescent Current ICC — 50 — mA

Min Logic 1 Input Voltage VIH 2.4 — — V

Max Logic 0 Input Voltage VIL — — 0.8 V

Input Resistance RIn — 10 — kΩ

Analog Output Range VOut 0 — 3.3 V

Bus Current Sense Voltage ISense — 412 — mV/A

Bus Voltage Sense Voltage VBus — 206 — mV/V

Power MOSFET On Resistance RDS(On) — 32 40 MΩ

RMS Output Current IM — — 6 A

Total Power Dissipation Pdiss — — 5 W


18 Operational Description MOTOROLA For More Information On This Product,


Operational DescriptionMotor Characteristics

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2.4 Motor Characteristics

The motor characteristics in Table 2-2 apply to operation at 25°C.

Table 2-2. Motor Characteristics

Characteristic Symbol Min Typ Max Units

Terminal Voltage Vt — — 60 V

Speed @ Vt — 5000 — RPM

Torque Constant Kt — 0.08 — Nm/A

Voltage Constant Ke — 8.4 — V/kRPM

Winding Resistance Rt — 2.8 — Ω

Winding Inductance L — 8.6 — mH

Continuous Current Ics — — 2 A

Peak Current Ips — — 5.9 A

Inertia Jm — 0.075 — kgcm2

Thermal Resistance — — 3.6 °C/W


MOTOROLA Operational Description 19 For More Information On This Product,


Operational Description

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20 Operational Description MOTOROLA For More Information On This Product,


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Section 3. Pin Descriptions

3.1 Contents

3.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.3 Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233.3.1 EVM Motor Board Power Connectors J3 and J4. . . . . . . . . . . . . . 233.3.2 EVM Motor Board 40-Pin Ribbon Connector J1 . . . . . . . . . . . . . 233.3.3 EVM Motor Board Output Connector J2. . . . . . . . . . . . . . . . . . . . 263.3.4 Motor Power Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.3.5 Motor Hall Sensor Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.3.6 Motor Encoder Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273.3.7 Motor Encoder Cable Connectors . . . . . . . . . . . . . . . . . . . . . . . . . 273.3.8 Test Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.2 Introduction

Inputs and outputs are located on eight connectors:

• Three connectors are located on the board.

• Three connectors are associated with the motor.

• Two connectors are attached to a cable for the encoder.

In addition, six test points are located on the right-hand side of the EVM motorboard’s breadboard area.

Pin descriptions for each of these connectors and the test points are identified inthe following information. Pin assignments for the input and output connectorsare shown in Figure 3-1. Signal descriptions are provided in Table 3-1 throughTable 3-5.


MOTOROLA Pin Descriptions 21 For More Information On This Product,


Pin Descriptions

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Figure 3-1. 40-Pin Input Connector J1

40393837363534333231302928272625242322212019181716151413121110987654321

BEMF_sense_CBEMF_sense_BBEMF_sense_AShieldingZero_cross_CZero_cross_BZero_cross_A

Serial_Con

Shielding

I_sense_DCBV_sense_DCB

+12VGNDAGNDA+3.3V_A+5V_D+5V_DGNDGNDPWM_CBShieldingPWM_CTShieldingPWM_BBShieldingPWM_BTShieldingPWM_ABShieldingPWM_AT

SCHEMATIC VIEW

J1

CON/40

2468

10121416182022242628303234363840

13579111315171921232527293133353739

ShieldingShieldingShieldingShieldingShieldingGND+5V_D+3.3V_AGNDA

I_sense_DCB

ShieldingSerial_Con

Zero_cross_AZero_cross_CBEMF_sense_ABEMF_sense_C

PWM_ATPWM_ABPWM_BTPWM_BBPWM_CTPWM_CB

GND+5V_DGNDA+12V

V_sense_DCB

Zero_cross_BShielding

BEMF_sense_B

PHYSICAL VIEW


22 Pin Descriptions MOTOROLA For More Information On This Product,


Pin DescriptionsSignal Descriptions

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3.3 Signal Descriptions

Pin descriptions are identified in this subsection.

3.3.1 EVM Motor Board Power Connectors J3 and J4

Two connectors, labeled J3 and J4, are provided for the 12-volt power supply.J3 and J4 are located on the bottom right-hand corner of the board. ConnectorJ3 is a 2.1-mm power jack for plug-in type 12-volt power supply connections.Connector J4 has screw terminal inputs labeled + (plus) and – (minus), foraccepting wire inputs. Power is supplied to one or the other, but not both. Thepower supply should be able to deliver at least 3.5 amps. For power supplies thatcan supply larger currents, 4 amps is the default current limit setting.

3.3.2 EVM Motor Board 40-Pin Ribbon Connector J1

Signal inputs are grouped together on 40-pin ribbon cable connector J1, locatedon the right side of the board. Pin assignments are shown in Figure 3-1. Pindescriptions are listed in Table 3-1.

Table 3-1. Connector J1 Signal Descriptions (Sheet 1 of 3)

PinNo.

Signal Name Description

1 PWM_ATPWM_AT is the gate drive signal for the top half-bridge of phase A. A logic high atinput connector J1 turns on the phase A top switch.

2 Shielding Pin 2 is connected to a shield wire in the ribbon cable, and ground on the board.

3 PWM_ABPWM_AB is the gate drive signal for the bottom half-bridge of phase A. A logic highat input connector J1 turns on the phase A bottom switch.


5 PWM_BTPWM_BT is the gate drive signal for the top half-bridge of phase B. A logic high atinput connector J1 turns on the phase B top switch.


7 PWM_BBPWM_BB is the gate drive signal for the bottom half-bridge of phase B. A logic highat input connector J1 turns on the phase B bottom switch.





Pin Descriptions

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9 PWM_CTPWM_CT is the gate drive signal for the top half-bridge of phase C. A logic high atinput connector J1 turns on the phase C top switch.


11 PWM_CBPWM_CB is the gate drive signal for the bottom half-bridge of phase C. A logic highat input connector J1 turns on the phase C bottom switch.

12 GND Digital power supply ground

13 GND Digital power supply ground, redundant connection

14 +5V_D Digital +5-volt power supply

15 +5V_D Digital +5-volt power supply, redundant connection

16 +3.3V_A Analog +3.3-volt power supply

17 GNDA Analog power supply ground

18 GNDA Analog power supply ground, redundant connection

19 +12V +12-volt power supply

20 — No connection

21 V_sense_DCBV_sense_DCB is an analog sense signal that measures dc bus voltage. It is scaledat 0.206 volts per volt of dc bus voltage.

22 I_sense_DCBI_sense_DCB is an analog sense signal that measures dc bus current. It is scaledat 0.412 volts per amp of dc bus current.








30 Serial_ConSerial_Con is an identification signal that lets the controller know which powerstage is present. It is nominally a 600-Hz square wave.





PinNo.






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34 Zero_cross_AZero_cross_A is a digital signal that is used for sensing phase A back-EMF zerocrossing events.

35 Zero_cross_BZero_cross_B is a digital signal that is used for sensing phase B back-EMF zerocrossing events.

36 Zero_cross_CZero_cross_C is a digital signal that is used for sensing phase C back-EMF zerocrossing events.


38 BEMF_sense_ABEMF_sense_A is an analog sense signal that measures phase A back EMF. It isscaled at 0.206 volts per volt of dc bus voltage.

39 BEMF_sense_BBEMF_sense_B is an analog sense signal that measures phase B back EMF. It isscaled at 0.206 volts per volt of dc bus voltage.

40 BEMF_sense_CBEMF_sense_A is an analog sense signal that measures phase C back EMF. It isscaled at 0.206 volts per volt of dc bus voltage.


PinNo.





Pin Descriptions

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3.3.3 EVM Motor Board Output Connector J2

Power outputs to the motor are located on connector J2, labeled “MotorConnector.” Pin assignments are described in Table 3-2.

3.3.4 Motor Power Connector

Motor power connections are grouped into a connector that plugs into the EVMmotor board’s motor connector, J2. Pin assignments are identical to EVM motorboard output connector J2.

3.3.5 Motor Hall Sensor Connector

Hall sensor connections are made with a connector that plugs into the controlboard’s Hall sensor/encoder connector. Pin assignments are described inTable 3-3.

Table 3-2. Connector J2 Signal Descriptions

PinNo.


1 Phase_A Phase_A supplies power to motor phase A. The motor wire color is white/red.

2 Phase_B Phase_B supplies power to motor phase B. The motor wire color is white/yellow.

3 Phase_C Phase_C supplies power to motor phase C. The motor wire color is white/black.

Table 3-3. Motor Hall Sensor Connector

PinNo.


1 +5V+5V supplies power from the control board to the Hall sensors. The wire color isred.

2 GND GND is the Hall sensor ground. The wire color is black.

3 Hall A Hall A is an open collector output from Hall sensor A. The wire color is green.

4 Hall B Hall B is an open collector output from Hall sensor B. The wire color is white.

5 Hall C Hall C is an open collector output from Hall sensor C. The wire color is blue.





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3.3.6 Motor Encoder Connector

The encoder connector has five pins. Pin 1 orientation is shown in Figure 4-6.Encoder Connector — Physical View. Pin assignments are described inTable 3-4.

3.3.7 Motor Encoder Cable Connectors

The encoder cable has two connectors, one at each end. They assume the pinassignments of their respective mating connectors, one on the EVM motorboard and the other on the control board.

3.3.8 Test Points

Six test points provide easy access to power supply and ground voltages. Theyare listed in Table 3-5 as they appear from top to bottom on the board.

Table 3-4. Motor Encoder Connector

PinNo.


1 GND Pin 1 is the encoder’s ground.

2 Index Pin 2 is the index output.

3 Channel A Pin 3 is the channel A output.

4 +5V Pin 4 supplies +5 volts from the control board to the encoder.

5 Channel B Pin 5 is the channel B output.

Table 3-5. Test Points

PinNo.


1 DCB_POS Test point DCB_POS is connected to the +12-volt motor bus.

2 GND Test point GND is connected to the 12-volt power supply and motor bus ground.

3 +3.3V_A Test point +3.3V_A is connected to the 3.3-volt analog power supply voltage.

4 GNDA Test point GNDA is connected to analog ground.

5 +5V_D Test point +5V_D is connected to the 5-volt digital power supply voltage.

6 GNDTest point GND is an additional connection to the 12-volt power supply and motorbus ground.




Pin Descriptions

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Section 4. Schematics and Parts List

4.1 Contents

4.2 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.3 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.4 Encoder Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.5 Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.2 Overview

A set of schematics for the EVM motor board appears in Figure 4-1 throughFigure 4-5. An overview of the whole board is shown in Figure 4-1. The3-phase H-bridge, including gate drivers, appears in Figure 4-2. Bus currentfeedback is shown in Figure 4-3. Back EMF signals appear in Figure 4-4. Thebrushless dc motor is shown in Figure 4-5.

Unless otherwise specified, resistor values are in ohms, resistors are specifiedas 1/8 watt ±5%, and interrupted lines coded with the same letters areelectrically connected.

4.3 Schematics

The schematics for the evaluation motor board appear on the following pages.


MOTOROLA Schematics and Parts List 29 For More Information On This Product,


eilding

o_cross_B

o_cross_A

F_sense_B

_CT

eilding

_AT

eilding

ense_DCB_3.3

eilding

ial_Con

V _CB

eilding

ense_DCB

o_cross_C

eilding

F_sense_C

eilding

_AB

_BB

_BT

F_sense_A

F

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5L

GN

D

GN

DA

+3

.3V

_A

GN

DA

J4 CO

N/2

scre

ws

12

+C

43.

3uF

/20V

GN

D

+5

V_

D

GN

D

+3

.3V

_A

R1

68

0

U3

LM25

74N

-55

4

1

23

7

VIN GND

FD

BK

GNDOFF O

UT

BR

EA

D B

OA

RD

10x

10

+3

.3V

_A

BR

EA

D B

OA

RD

10x

10

GN

D

J2 AM

P 6

4038

7-3

123

D4

MB

RM

140T

3

GN

D

+C

222

0uF

/10V

+3

.3V

_A

GN

DA

D1

6S

MB

18

AT

3

DC

B_

Po

s

GN

D

+5

V_

D

+5

V_

D

+5

V_

D

3-ph

. H

brid

ge,

driv

ers

PW

M_

AT

PW

M_

AB

Ph

ase

_A

Ph

ase

_B

Ph

ase

_C

PW

M_

BT

PW

M_

BB

PW

M_C

TP

WM

_C

B

DC

B_

Po

sD

CB

_Neg

V_

sen

se_

DC

B_

ha

lfV

_se

nse

_D

CB

I_S

en

se_

DC

B2

I_S

en

se_

DC

B1

GN

D

L1

330u

H

J3 ack

3

DC

B_P

OS

DC

B_P

OS

GN

DA

GN

D

GN

D

GN

D

GN

D

+3

.3V

_A

GN

DA

+C

33.

3uF

/20V

Cur

rent

pro

cess

ing

Cur

rent

pro

cess

ing

I_se

nse

_D

CB

GN

DA

+3

.3V

_A

I_se

nse

_D

CB

2I_

sen

se_

DC

B1

+C

122

uF/2

5VB

ack

EM

F

Phase_B

GN

DA

+5

V_

D

BE

MF

_se

nse

_C

Zer

o_cr

os_C

Zer

o_cr

os_B

Phase_A

BE

MF

_se

nse

_A

V_sense_DCB_half

Phase_C

Zer

o_cr

os_A

BE

MF

_se

nse

_B

GN

D

Ide

ntif

ica

tion

GN

D

GC

1

Gro

und_

Con

nect

ion

+5

V_

D

GN

DA

D3

LED

Gre

en

GN

DA

GN

D

+5

V_

D

D5 BZ

X84

C5V

6LT

1

GN

D

GN

D

Sh

Zer

Zer

BEM

PWM Sh

PWMSh

V_s Sh

J1 CO

N/4

0

12345678910

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

Ser

+12

PWM Sh

I_s

Zer Sh

BEM Sh

PWM

PWM

PWM

BEM

U2

MC

78P

C33

NT

R1

52

3

Vin

Vo

ut

Gnd

CE

GN

DA

Fig

ure

4-1

. M

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r E

valu

atio

n M

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ule

Ove

rvie

w

D2

MB

RD

83

F1

RU

E40

0

P

Pow

er J

1

2



ense_DCB

107

2-1%

Phase_C

DCB_Pos

ense_DCB_half

V @ 16V

104

8-1%

0V @ 16V

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ure

4-2

. 3

Ph

ase

H-B

rid

ge

D102

MBRM140T3

B

Gate_CB

V_s

Gate_AT

DCB_Neg

DCB_Pos

D106

MBRM140T3

C107

100nF

R 18

Gate_BB

DCB_Pos

Gate_CB

Phase_A

OUTB

INB

GND

INA

OUTA

VDD

U103

MAX628CSA

2

3

5

6

7

4

OUTB

INB

GND

INA

OUTA

VDD

U102

MAX628CSA

2

3

5

6

7

4

R114

330

+C104

4.7uF/35V

I_Sense_DCB2

R102

10.7k-1%

R120

330

Gate_CT

R113

10k

+C106

4.7uF/35V

C108

100nF

R124

330

PWM_CT

R121

100

R109

10k

+C103

330uF/35V

Gate_BB

OUTB

INB

GND

INA

OUTA

VDD

U101

MAX628CSA

2

3

5

6

7

4

R123

100

R125

100

Gate_AB

R106

10k

R103

2.0k-1%

C109

100nF

R119

100

Phase_B

DCB_Neg

Gate_BT

DCB_Pos

+C105

4.7uF/35V

V_s

Q102

Si4558DY

13

24

5678

3.0

R117

100

DCB_Neg

R115

100

R 11

R105

10k

DCB_Neg

R116

330

Q103

Si4558DY

13

24

5678

D103

MBRM140T3

R122

330

sense

senseR101

PMA-A-R075-1

Gate_AT

D104

MBRM140T3

I_Sense_DCB1

D101

MBRM140T3

+C101

330uF/35V

Gate_CT

R110

1.82k-1%

R111

1.18k-1%

Gate_AB

R108

10k

R112

10k

Gate_BT

PWM_CB

R118

330

T

3.3

Q101

Si4558DY

13

24

5678

+C102

330uF/35V

D105

MBRM140T3

PWM_A

DCB_Neg

DCB_Neg

DCB_Pos

DCB_Pos

DCB_Pos

DCB_Neg

PWM_BB

PWM_BTPWM_A



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U30

2L

M2

85

M

8

5

4

C30

310

0nF

R30

5

39

0

( +/-297 mV @ +/- Imax)

C30

1

100n

F

+3

.3V

_A

I_se

nse

_D

CB

GN

DA

R30

321

k-1%

+

C30

23.

3uF

/10V

I_se

nse

_D

CB

1

GN

DA

1.65V ref

+3

.3V

_A

GN

DA

GN

DA

R30

610

0k-1

%

+-

U3

01

AM

C33

502D

321

84

+3

.3V

_A

+3

.3V

_A

GN

DA

GN

DA R30

221

k-1%

R30

733

.2k-

1%

+-

U3

01

BM

C33

502D

567

GN

DA

(1.65V +/- 1.65V @ +/- Imax)

I_se

nse

_D

CB

2

R30

410

5k-1

%

R30

1

105k

-1%

Fig

ure

4-3

. B

us

Cu

rren

t F

eed

bac

k



Ide

ntif

ica

tion

F

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+ -U

20

1A

LM33

9D

5 42

3 12

Ph

ase

_B

R21

51

M

C20

3

100n

F

Zer

o_cr

oss_

B+ -

U20

1DLM

339D

11

10

13

_C = 12V)

C20

610

0nF

R21

1

10

k

GN

DA

GN

D

R20

65

.6k

GN

D

GN

D2.5V @ Phase_B = 12V)

R20

41

0k

+ -U

201C

LM33

9D

9 81

4

R22

2

10

k

R22

05

.6k

R22

4

33

kR

210

2.67

k-1%

V_

sen

se_

DC

B_

ha

lf

GN

D

+5

V_

DR

225

33

k

GN

DA

C20

210

0pF

R21

610

k-1%

+ -U

20

1B

LM33

9D

7 61

GN

DA

GN

DA

+5

V_

D

Zer

o_cr

oss_

AR

207

3.32

k-1%

GN

D

R21

35

.6k

R21

8

10

k

R20

32.

67k-

1%G

ND

C20

410

0pF

GN

DA

BE

MF

_se

nse

_A

R22

63

3k

R21

72.

67k-

1%

GN

DA

Zer

o_cr

oss_

C

+5

V_

D

R21

21

0k

C20

522

pF

(2.5V @ Phase_A = 12V)

R20

110

k-1%

GN

DA

R21

91

0k

C20

110

0pF

R20

51

0k

GN

DA

+5

V_

D

R20

21

M

C

R22

13.

32k-

1%

EM

F_

sen

se_

B

+5

V_

D

R22

31

0k

R20

91

M

GN

DA

+5

V_

D

R20

810

k-1%

Ph

ase

_A

+5

V_

D

R21

43.

32k-

1%

Fig

ure

4-4

. B

ack

EM

F S

ign

als

(2.5V @ Phase(

BE

MF

_se

nse

_C

Ph

ase

_B



Schematics and Parts List

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Figure 4-5. Brushless dc Motor Connections — Schematic View

4.4 Encoder Connector

The encoder is shown in Figure 4-6. The mark on the motor in this viewindicates pin 1 on the encoder’s 5-pin connector.

MOTOROLAEMBEDDED MOTION CONTROL

SERIES

J4

Phase_C

Phase_B

Phase_A

BRUSHLESS

+ 12 Vdc

56800 EVALUATION MODULEOR

40-PINRIBBON CABLE

1 2 3 4 5

MOTOR

HC08 CONTROL BOARD

MOTOROLAEMBEDDED MOTION CONTROL

SERIESEVM MOTOR BOARD

3

2

1

J2

HALL/ENCODERCONNECTOR

WHITE/RED

WHITE/YELLOW

WHITE/BLACK

+

–

J1

HALL C (BLUE)

HALL B (WHITE)

HALL A (GREEN)

GND (BLACK)

+5V (RED)


34 Schematics and Parts List MOTOROLA For More Information On This Product,


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Fig

ure

4-6

. E

nc

od

er C

on

ne

cto

r –

Ph

ys

ica

l Vie

w




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.

4.5 Parts List

The EVM motor board’s parts content is described in the following parts list.

Table 4-1. Parts List (Sheet 1 of 3)

Qty. Reference Part Value Description Mfg. Mfg. Part No.

1 C1 22 µF/25 VTantalum capacitor, D,22 µF/25 V, ±10%,ESR 0.2

AVX TPSD226K025R0200

1 C2 220 µF/10 VElectrolytic Capacitor220 µF/10 V, Type RE2

ELNA RE2-10V221MMA

2 C3, C4 3.3 µF/ 20 VTantalum Capacitor, A,3.3 µF/20 V, ±10%

Vishay Sprague 293D335X_010A2

3 C101, C102, C103 330 µF/35 VElectrolytic Capacitor330 µF/35 V, Type RE2

ELNA RE2-35V331MMA

3 C104,C105,C106 4.7 µF/35 VTantalum Capacitor, D,4. 7µF/35 V, ±10%

Vishay Sprague 293D475X_035D2

7C107, C108, C109,C203, C206,C301, C303

100 nFCapacitor, 805,Ceramic 100 nF/25 V,Z5U, ±20%

Vishay Vitramon VJ0805U104MXXA

3 C201, C202, C204 100 pFCeramic capacitor,0805, 100 pF, ±5%

Vishay Vitramon VJ0805A101JXA

1 C205 22 pFCeramic capacitor,0805, 22 pF, ±5%

Vishay Vitramon VJ0805A220JXA

1 C302 3.3 µF/10 VTantalum capacitor, A,3.3 µF/10 V, ±10%

Vishay Sprague 293D335X_010A2

1 D1 P6SMB18AT3Transient voltagesuppressor 18 V

ONSemiconductor

P6SMB18AT3

1 D2 MBRD835LLow VF ShottkyRectifiers 35 V, 8 A

ONSemiconductor

MBRD835L

1 D3 LED GreenLED diode, 3mm,10 mA, green

Kingbright L-934GT

7D4, D101, D102,D103, D104, D105,D106

MBRM140T3Shottky Rectifiers 40 V,1A

ONSemiconductor

MBRM140T3

1 D5 BZX84C5V6LT1 Zener diode 5.6 VONSemiconductor

BZX84C5V6LT1

1 F1 RUE400 Resetable fuse Raychem RUE400

1 J1 CON/40Header 40 pinsbreakaway connector

FischerElektronik

ASLG40G

1 J2 AMP 640387-3 Header 3 pins AMP 640387-3

1 J3 Power JackPower Jack typeconnector 2.1 mm

CUI Stack PJ-002A




Schematics and Parts ListParts List

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1 J4 CON/2screws2 screws PCB terminal,200 mils

WAGO 237-132

1 L1 330 µHInductor 330 µH, 0.5 A,thruhole, d = 9mm

Bourns RLB0914-331K

3 Q101, Q102, Q103 Si4558DYP+ N MOSFETtransistor, 30 V, 6 A

Vishay Si4558DY

1 R1 680Resistor 680 Ω, 5%,0805

Vishay Dale CRCW0805-681J

1 R101 PMA-A-R075-1Sensing resistor withKelvin terminals,75 MΩ, 1%

Isabellenhutte PMA-A-R075-1

3 R201, R208, R216 10 k-1%Resistor 10 kΩ, 1%,0805

Vishay Dale CRCW0805-1002F

3 R203, R210, R217 2.67 k-1%Resistor 2.67 kΩ, 1%,0805


1 R104 118-1%Resistor 118 Ω, 1%,0805


14

R105, R106, R108,R109, R112, R113,R204, R205, R211,R212, R218, R219,R222, R223

10 kResistor 10 kΩ, 5%,0805


1 R107 182-1%Resistor 182 Ω, 1%,0805


1 R110 1.82 k-1%Resistor 1.82 kΩ, 1%,0805


1 R111 1.18 k-1%Resistor 1.18 kΩ, 1%,0805


3 R202, R209, R215 1 MResistor 1 MΩ, 5%,0805


3 R206, R213, R220 5.6 kResistor 5.6 kΩ, 5%,0805


3 R207, R214, R221 3.32 k-1%Resistor 3.32 kΩ, 1%,0805


3 R224, R225, R226 33 kResistor 33 kΩ, 5%,0805


2 R301, R304 105 k-1%Resistor 10 5kΩ, 1%,0805


2 R302, R303 21 k-1%Resistor 21 kΩ, 1%,0805


1 R305 390Resistor 390 Ω, 5%,0805





MOTOROLA Schematics and Parts List 37 For More Information On This Product,



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1 R306 100 k-1%Resistor 100 kΩ, 1%,0805


1 R307 33.2 k-1%Resistor 33.2 kΩ, 1%,0805


6R114, R116, R118,R120, R122, R124

330Resistor 330 Ω, 5%,0805


6R115, R117, R119,R121, R123, R125

100Resistor 100 Ω, 5%,0805


1 U2 MC78PC33NTRLinear voltageregulator

ONSemiconductor

MC78PC33NTR

1 U3 LM2574N-005Switching voltageregulator

ONSemiconductor

LM2574N-5

3 U101, U102, U103 MAX628CSA MOSFET driver Maxim MAX4428CSA

1 U201 LM339D ComparatorONSemiconductor

LM339D

1 U301 MC33502DOperational amplifier,rail to rail

ONSemiconductor

MC33502D

1 U302 LM285MAdujstable voltagereference

NationalSemiconductor

LM285M

1 R103 2.0 k-1%Resistor 2.0 kΩ, 1%,0805


1 R102 10.7 k-1%Resistor 10. 7kΩ, 1%,0805







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Section 5. Design Considerations

5.1 Contents

5.2 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.3 3-Phase H-Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.4 Bus Voltage and Current Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.5 Back EMF Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

5.2 Overview

From a systems point of view, the EVM motor board kit fits into an architecturethat is designed for code development. In addition to the hardware that is neededto run a motor, a variety of feedback signals that facilitate control algorithmdevelopment are provided.

The EVM motor board’s power output stage is a complementary MOS fieldeffect transistor (MOSFET) 3-phase bridge that is capable of supplying andsensing 4 amps of continuous current. Feedback signals include bus voltage,bus current, back EMF (electromotive force), and zero crossing. Descriptions ofeach of these blocks are contained in 5.3 3-Phase H-Bridge, 5.4 Bus Voltageand Current Feedback, and 5.5 Back EMF Signals.

5.3 3-Phase H-Bridge

The output stage is configured as a 3-phase H-bridge with complementaryMOSFET output transistors. It is simplified considerably by dual integratedgate drivers that each have one inverting and one non-inverting driver. Asimplified schematic that shows one phase is illustrated in Figure 5-1.


MOTOROLA Design Considerations 39 For More Information On This Product,


Design Considerations

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Figure 5-1. Phase A Output

At the input, pulldown resistors, R105 and R108, set a logic low in the absenceof a signal. Open input pulldown is important, since it is desirable to keep thepower transistors off in case of either a broken connection or absence of poweron the control board. Gate drive is supplied by a Maxim MAX628CSA. Thispart has a minimum logic 1 input voltage of 2.4 volts and maximum logic 0input voltage of 0.8 volts. The EVM motor board will, therefore, accept inputsfor either 3.3- or 5-volt logic. Under voltage lockout is not included in the gatedrive. If this feature is desired, the control board’s under-voltage detectioncomparator can be set for 1.24 volts.

One of the more important design decisions in a motor drive is selection of gatedrive impedance for the output transistors. In Figure 5-1, resistors R116, R117,and diode D102 determine gate drive impedance for the lower half-bridgetransistor. A similar network is used on the upper half-bridge. These networksset turn-on gate drive impedance at approximately 430 Ω and turn-off gate driveimpedance at approximately 100 Ω. These values produce transition times ofapproximately 60 ns.

Transition times of this length represent a carefully weighed compromisebetween power dissipation and noise generation. Generally speaking, transitiontimes longer than 250 ns tend to get power hungry at non-audible PWM rates;and transition times under 50 ns create di/dt’s so large that proper operation isdifficult to achieve. The EVM motor board is designed with switching times atthe lower end of this range to minimize power dissipation.

DCB_Pos

PWM_AT

PWM_AB

DCB_Neg

R105

10 k

R108

10 k2

4

U101

INA

INB

GND

3

6VDD

OUTA

OUTB

7

5

MBRM140T3

MBRM140T3

D101

R114

R116

330 Ω

D102

R117

100 Ω

100 Ω

R115

4

2

1

8Q101

330 Ω

3

7

6

5 Phase_A

Si4558DYMAX628CSA


40 Design Considerations MOTOROLA For More Information On This Product,


Design ConsiderationsBus Voltage and Current Feedback

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5.4 Bus Voltage and Current Feedback

Feedback signals proportional to bus voltage and bus current are provided bythe circuitry shown in Figure 5-2. Bus voltage is scaled down by a voltagedivider consisting of R102, R103, R104, R107, R110, and R111. The values arechosen such that a 16-volt maximum bus voltage corresponds to a 3.3-voltmaximum analog-to-digital (A/D) input. Bus current is sampled by resistorR101 in Figure 4-2 and amplified by the circuit in Figure 5-2. This circuitprovides a voltage output suitable for sampling with A/D inputs. An MC33502is used for the differential amplifier. The gain is given by:

A = R301/R302

The output voltage is shifted up by 1.65 V, to accommodate both positive andnegative current swings. A ±300-mV voltage drop across the shunt resistorcorresponds to a measured current range of ±4.0 amps.

Note that the EVM motor board measures, but does not limit, current. Currentlimiting is performed on the control board, where a 2.8-volt setting for theovercurrent detection comparator produces a 2.8-amp current limit.

Figure 5-2. Bus Feedback

+

–R302 21 k-1%

R303 21 k-1%R304105 k-1%

R306100 k-1%

R30733.2 k-1%

GNDA

LM285MU302

R305

390 Ω+3.3V_A

I_sense_DCB1

I_sense_DCB2

5

4

8

1.65 Vref

I_sense_DCB

R301

105 k-1%

2

31U301AMC33502D

DCB_Pos

DCB_Neg

R102

10.7 k-1% 2.0 k-1%

R103 V_sense_DCB

R110

1.18 k-1%1.82 k-1%

R111

182 ΩR107

118 ΩR104

V_sense_DCB_half

8


MOTOROLA Design Considerations 41 For More Information On This Product,


Design Considerations

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5.5 Back EMF Signals

Back EMF and zero crossing signals are included to support sensorlessalgorithms for brushless dc motors. Referring to Figure 5-3, which showscircuitry for phase C, the raw phase voltage is scaled down by a voltage dividerconsisting of R216, R217, and R221. One output from this divider producesback EMF sense voltage BEMF_sense_C. Resistor values are chosen such thata 16-volt maximum phase voltage corresponds to a 3.3-volt maximum A/Dinput.

A zero crossing signal is obtained by comparing motor phase voltage with themotor bus voltage. Comparator U201A performs this function, producing zerocrossing signal Zero_cross_C.

Figure 5-3. Phase C Back EMF Feedback

–

+

GNDA

GNDA GNDA

10 k-1%R216

R2172.67 k-1%

R2213.32 k-1%

10 kR218

C204100 pF

R2205.6 k

C20522 pF

V_sense_DCB_half

R215

1 M

10 kR219

+5V_D

U201ALM339D

3

4

5

12

2 Zero_cross_CBEMF_sense_C

Phase_C


42 Design Considerations MOTOROLA For More Information On This Product,


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MEMCEVMBUM/D

© Motorola, Inc., 2000

Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of itsproducts for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability,including without limitation consequential or incidental damages. "Typical" parameters which may be provided in Motorola data sheets and/or specifications can and do vary in differentapplications and actual performance may vary over time. All operating parameters, including "Typicals" must be validated for each customer application by customer's technical experts.Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systemsintended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create asituation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and holdMotorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of,directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding thedesign or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer.

How to reach us:USA/EUROPE/Locations Not Listed: Motorola Literature Distribution, P.O. Box 5405, Denver, Colorado 80217. 1-303-675-2140

or 1-800-441-2447. Customer Focus Center, 1-800-521-6274JAPAN: Motorola Japan Ltd.; SPS, Technical Information Center, 3-20-1, Minami-Azabu, Minato-ku, Tokyo 106-8573 Japan.

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Tai Po, N.T., Hong Kong. 852-26668334HOME PAGE: http://motorola.com/semiconductors/

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