Western Washington University

Wireless Smart Charging System for Mobile Devices EE 492

Jacie Unpingco 3-17-2016

TABLE OF CONTENTS 1. Design Change Form…………………………………………………………………………………………………………………….........1

2. Schematic Sheets

a. MCU, Battery, and LEDs Schematic……………………………………………………………………………………………….2

b. Transmitter Circuit Schematic……………………………………………………………………………………………………….3

c. Receiver Board Schematic………………………………………………………………………………………………………..……4

3. Board Layouts

a. Main Board Top Copper Layer……………………………………………………………………………………………………….5

b. Main Board Bottom Copper Layer…………………………………………………………………………………………………6

c. Receiver Board Top Copper Layer………………………………………………………………………………………………….7

d. Receiver Board Bottom Copper Layer……………………………………………………………………………………………8

4. 3D Board Renderings

a. Main Board 3D PCB…………………………………………………………………………………………………………………….…9

b. Receiver Board 3D PCB (Enlarged)………………………….……………………………………………………………………10

5. Complete Bill of Materials

a. MCU, Battery, LEDs, and Transmitter Circuit BOM………………………………………………………………………11

b. Receiver Circuit BOM………………………………………………………………………………………………………………..…12

6. 3D Overall Designs from Industrial Design Students

a. Justin Janczakowski’s Design…………………………………………………………………………………………….…………13

b. Calyn McLeod’s Design……………………………………………………………………………………………………..…………14

c. Emily Bartlett’s Design…………………………………………………………………………………………………………………15

7. Solder Paste Stencils………………………………………………………………………………………………………………….………16

8. Solder Paste Stenciled Boards……………………………………………………………………………………………………………17

9. PCB Boards After Reflow……………………………………………………………………………………………………………………18

10. Board Test Procedures………………………………………………………………………………….…………………………………..19

11. Identified Errors/Connections for Next Board Iteration……………….…………………………………………………….20

1

Electrical Engineering

Engineering Change Description EE 492 – Project Hardware Design

Page: 1 of 1

Project Name: Wireless Smart Charging System for

Mobile Devices Revision: 1.0.0

Reason For Change:

The original user interface design has since changed

since I submitted my project description due to the

designs of the industrial design students I am

working with.

Source Signature Date

Originator Jacie Unpingco 3-17-2016

Instructor

Description of Change:

Originally, the user interface had the LEDs on the top of the charging pad. With the new interface design

in collaboration with the industrial design students, the LEDs will exist on the side of the charging pad

along with the on/off switch. The switch and the LEDs are located to the far left of the front panel when

looking at the pad straight on. In addition, there is a micro-USB port added to the user interface so that

the charging pad itself can recharge the Lithium-Polymer battery within.

2

SCHEMATIC SHEETS

Figure 1: MCU, Battery, and LEDs Schematic

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Figure 2: Transmitter Circuit Schematic

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Figure 3: Receiver Board Schematic

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BOARD LAYOUTS

Figure 4: Main Board Top Copper Layer

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Figure 5: Main Board Bottom Copper Layer

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Figure 6: Receiver Board Top Copper Layer

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Figure 7: Receiver Board Bottom Copper Layer

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3D BOARD RENDERINGS

Figure 8: Main Board 3D PCB

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Figure 9: Receiver Board 3D PCB (Enlarged)

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Bill of Materials MCU, Battery, LEDs, & Transmitter Circuit

Source Data From: Senior_Project.PrjPcb

Project: Senior_Project.PrjPcb

Variant: None

Creation Date: 2/29/2016 4:11:46 PM

Print Date: 18-Mar-16 12:00:58 AM

Production Quantity: 1

Currency USD

Description

Manufacturer Part # Value Designator Quantity LiPo Battery

B1 1

CAP 4.7uF 6.3V ±10% 0603 (1608 Metric) SMD 4.7uF C1, C2, C10 3

CAP 12pF 50V ±10% 0603 (1608 Metric) SMD 12pF C3, C4 2

CAP 1uF 16V ±10% 0603 (1608 Metric) SMD 1uF C5 1

CAP 100nF 50V ±10% 0603 (1608 Metric) SMD 100nF C6 1

CAP 2.2uF 10V ±10% 0603 (1608 Metric) SMD 2.2uF C7 1

CAP 470pF 50V ±10% 0603 (1608 Metric) SMD 470pF C8 1

CAP 10uF 10V ±10% 0603 (1608 Metric) SMD 10uF C9 1

CAP 220nF 25V ±10% 0603 (1608 Metric) SMD 220nF C11 1

10 pin 0.05" pitch header for JTAG

J1 1

CONN USB MICRO B RECPT SMT R/A 10118194-0001LF

J2 1

FIXED IND 4.7UH 3A 40.3 MOHM SMD NR6028T4R7M

L1 1

WIRELESS CHARGING COIL ASSEMBLY AWCCA-50N50H35-C01-B

L2 1

LED RED CLEAR 0603 SMD LTST-C194KRKT

LED1 1

LED GREEN CLEAR 0603 SMD LTST-C194KGKT

LED2 - LED5 4

TRANS NPN 40V 0.2A SMD SOT23-3 MMBT3904-7-F

Q1 - Q4, Q9 5

MOSFET N-CH 30V 1.5A SOT-23 NTR4503NT1G

Q5, Q6, Q7, Q8 4

1K 0.1W 5% 0603 (1608 Metric) SMD 1k Ω R1, R14 - R17 5

10K 0.1W 5% 0603 (1608 Metric) SMD 10k Ω R2, R22 - R25 5

2K 0.1W 5% 0603 (1608 Metric) SMD 2k Ω R3 1

Jumper 0603 (1608 Metric) 0 Ω R4, R6, R7, R8, R21 5

10M 0.1W 1% 0603 (1608 Metric) SMD 10M Ω R5 1

221R 0.1W 1% 0603 (1608 Metric) SMD 221 Ω R9, R10, R11, R12 4

51K 0.1W 1% 0603 (1608 Metric) SMD 51k Ω R13, R19 2

976K 0.1W 1% 0603 (1608 Metric) SMD 976k Ω R18 1

309K 0.1W 1% 0603 (1608 Metric) SMD 309k Ω R20 1

4-40 Screw

Screw1 - Screw4 4

Horizontal SMT Slide Switch JS102011SAQN

SW1 1 TEST POINT PC MINI .040"D BLACK 5001

TP1 - TP4 TP14 14

IC CONTROLLR LI-ION 4.2V SOT23-5 MCP73831T-2ACI/OT

U1 1

IC MCU ARM 32KB FLASH 32LQFP MKL05Z32VLC4

U2 1

IC REG LDO 3.3V 0.5A (350 mV DROP) SOT23-5 MIC5219-3.3YM5 TR

U3 1

IC REG BST ADJ 0.1A SYNC SOT23-6 MCP1640T-I/CHY

U4 1

CRYSTAL 32.7680KHZ 9PF SMD 32.768KHZ

X1 1

79

12

Bill of Materials Receiver Circuit

Source Data From: RX_Board.PrjPcb

Project: RX_Board.PrjPcb

Variant: None

Creation Date: 2/29/2016 4:29:19 PM

Print Date: 18-Mar-16 12:20:22 AM

Production Quantity: 1

Currency USD

Description Manufacturer Part # Value Designator Quantity

CAP 100nF 50V ±10% 0603 (1608 Metric) SMD 100nF C1 1

CAP 10uF 6.3V ±10% 0603 (1608 Metric) SMD 10uF C2 1

CAP 1.5nF 50V ±10% 0603 (1608 Metric) SMD 1.5nF C3 1

DIODE GEN PURP 1KV 1A SMA S1M-13-F

D1 - D4 4

CONN USB MICRO B RECPT SMT R/A 10118194-0001LF

J1 1

RECEIVER 1 COIL 1 LAYER 760308103215

L1 1

TEST POINT PC MINI .040"D BLACK 5001

TP1, TP2, TP3 3

IC REG LDO 5V 1A SOT223 LM340MPX-5.0/NOPB

U1 1

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3D OVERALL DESIGNS FROM INDUSTRIAL DESIGN STUDENTS

Justin Janczakowski’s Industrial Design

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Calyn McLeod’s Industrial Design

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Emily Bartlett’s Industrial Design

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SOLDER STENCILS

Figure 10: Main Board Solder Stencil

Figure 11: Receiver Board Solder Stencil (Enlarged)

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SOLDER PASTE STENCILED BOARDS

Figure 12: Main Board with Solder Paste

Figure 13: Receiver Board with Solder Paste

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PCB BOARDS AFTER REFLOW

Figure 14: Main Board with Parts Placed After Reflow

Figure 15: Receiver Board with Parts Placed After Reflow

19

BOARD TEST PROCEDURES

Main Board

MCU and Battery

-Apply power and ground to the board using a power supply

-Check each test point to ensure that power is flowing through the board

-Ensure that the battery regulator circuit is working properly by checking that LED1 is on

-Using a DMM measure the charge current flowing through the battery

-Connect the 0 Ohm resistor, R7, to connect the low-dropout regulator and boost regulator

-Using a DMM, make sure that the LDO is outputting 3.3 V and the boost regulator is outputting 8V

-Using a DMM, make sure there are no shorts on the microcontroller pins

-Make sure that LED2 through LED5 are on when the board has a full charge

-Using the JTAG, add code to the MCU to ensure that it is functioning properly

Transmitter Circuit

-Apply power and ground to the circuit using a power supply

-Check each test point to ensure that power is flowing through the circuit

-Test the voltage across the charging coil to ensure the circuit is functioning properly

-Connect the 0 Ohm resistor, R21 to connect to the rest of the board

Receiver Board

-Apply power and ground to the board using a power supply

-Check each test point to ensure that power is flowing through the board

-Using a DMM, measure the voltage at test point 2 to ensure that it is approximately 5V

-Using a DMM, measure the voltage and current at test point 1 to ensure an adequate charging

20

IDENTIFIED ERRORS/CONNECTIONS FOR NEXT BOARD ITERATION

-Add 0 Ohm resistors to both sides of both the transmitter and receiver coils to be able to simulate a

charging voltage without ruining the charging coils

-Choose another boost regulator that can handle 8V and higher

-Add an additional LED for board life indication to match original project description and industrial

students’ designs