Texas Instruments bq51020EVM User Manual
User's Guide
SLUUB03–April 2014
bq51020EVM (5-W WPC) Integrated Wireless Receiver
Power Supply
The bq51020EVM-520 (PWR520-002) wireless power receiver evaluation kit (EVM) from TI is a high
performance, easy-to-use development kit for the design of wireless power solutions. It helps designers to
evaluate the operation and performance of the bq51020 IC, a secondary-side receiver device for wireless
power transfer in portable applications. The bq51020 device is a fully-contained, wireless power receiver
capable of operating in WPC v1.1 protocol which allows a wireless power system to deliver up to 5 W to
the system when used with a Qi inductive transmitter. The bq51020 device provides a single device power
conversion (rectification and regulation) as well as the digital control and communication for WPC
specification. The kit enables designers to speed up the development of their end-applications.
Contents
1 Introduction ................................................................................................................... 2
2 Considerations with this EVM.............................................................................................. 2
3 Modifications.................................................................................................................. 3
4 Recommended Operation Condition ...................................................................................... 3
5 Equipment and EVM Setup................................................................................................. 4
5.1 Schematic............................................................................................................ 4
5.2 Connector Descriptions ............................................................................................ 5
5.3 Jumpers and Switches............................................................................................. 5
5.4 Test Point Descriptions ............................................................................................ 5
5.5 Pin Description of the IC .......................................................................................... 6
6 Test Procedure............................................................................................................... 6
6.1 Definition............................................................................................................. 6
6.2 Recommended Test Equipment .................................................................................. 7
6.3 Equipment Setup.................................................................................................... 7
6.4 Procedure............................................................................................................ 8
7 Test Results................................................................................................................. 11
7.1 Steady-State Operation with bq2425x Charger .............................................................. 11
7.2 Load Step .......................................................................................................... 12
7.3 Start Up............................................................................................................. 12
7.4 Efficiency Data..................................................................................................... 13
7.5 AD Insertion and Removal ...................................................................................... 13
7.6 Thermal Performance............................................................................................. 14
8 Layout and Bill of Material ................................................................................................ 15
8.1 bq51020 Traces .................................................................................................. 15
8.2 Layout Guidelines ................................................................................................. 15
8.3 Printed-Circuit Board Layout Example ......................................................................... 15
8.4 bq51020EVM-520 Layout ........................................................................................ 17
8.5 Bill of Materials (BOM)............................................................................................ 20
List of Figures
1 bq51020EVM-520 Schematic .............................................................................................. 4
2 bq51020 in Steady State Operation with bq24250 .................................................................... 11
3 Load Step ................................................................................................................... 12
4 Start Up With 500 mA ..................................................................................................... 13
5 System Efficiency Versus Output Power ............................................................................... 13
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Introduction
6 Adapter Insertion and Removal .......................................................................................... 14
7 Thermal Image (1000-mA Load) ........................................................................................ 14
8 bq51020EVM-520 Layout Example ..................................................................................... 16
9 bq51020EVM-520 Top Assembly ....................................................................................... 17
10 bq51020EVM-520 Layer 1 ................................................................................................ 17
11 bq51020EVM-520 Layer 2 ................................................................................................ 18
12 bq51020EVM-520 Layer 3 ................................................................................................ 18
13 bq51020EVM-520 Layer 4 ................................................................................................ 19
1 bq51020EVM-520 Electrical Performance Specifications.............................................................. 3
2 Pin Description............................................................................................................... 6
3 bq51020EVM-520 Bill of Materials ...................................................................................... 20
1 Introduction
The bq51020 is an advanced, flexible, secondary-side device for wireless power transfer in portable
applications. The bq51020 device integrates an ultra-low-impedance synchronous rectifier, a very-highefficiency post regulator, digital control, and accurate voltage and current loops. The bq51020 devices
provide the AC/DC power conversion while integrating the digital control required. The IC complies with
the WPC v1.1 communication protocol.
Together with the bq500xxx primary-side controller transmitter, the bq51020 enables a complete
contactless power transfer system for a wireless power supply solution. By utilizing near-field inductive
power transfer, the secondary coil embedded in the mobile device can pick up the power transmitted by
the primary coil. The voltage from the secondary coil is then rectified and regulated to be used as a power
supply for down-system electronics. Global feedback is established from the secondary to the primary in
order to control the power transfer process.
A WPC system communication is digital -– packets are transferred from the secondary to the primary.
Differential bi-phase encoding is used for the packets. The bit rate is 2Kbps. Various types of
communication packets have been defined. These include identification and authentication packets, error
packets, control packets, power usage packets and efficiency packets, among others.
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List of Tables
2 Considerations with this EVM
The bq51020EVM-520 evaluation module (PWR520-002) demonstrates the receiver portion of the
wireless power system. This receiver EVM is a complete receiver-side solution that produces 5-W output
power at up to 1-A load with adjustable output voltage.
• The receiver can be used in any number of low-power battery portable devices as a power supply for a
battery charger. With contact-free charging capability, no connections to the device are needed.
• Highly-integrated wireless power receiver solution
– Ultra-efficient synchronous rectifier
– Very-high efficiency post regulator
– WPC v1.1-compliant communication and control
– Only one IC required between RX coil and DC output
• Programmable output voltage to optimize performance for application
• Adaptive Communication current limit (CM_ ILIM) for robust communication.
• Supports 20-V max input
• Low-power dissipative overvoltage clamp
• Overvoltage, overcurrent, overtemperature protection
• Low-profile, external pick-up coil
• Frame is configured to provide correct receiver to transmitter spacing
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• Room above coil for testing with battery, key for Foreign Object Detection (FOD) tuning
• Options to adjust the input current limit and output voltage using resistors
• Flexibility for Foreign Object Detection (FOD) tuning
• Adjustable resistor that can be used to set RFOD
• Temperature sensing can be adjusted using external resistors
• Micro-USB connector for adapter testing configuration
• WPG LED indicator (turns on as V
OUT
• PD_DET LED indicator --turns on as the RX is on TX pad
3 Modifications
See the data sheet (SLUSBX1) when changing components. To aid in such customization of the EVM, the
board was designed with devices having 0402 and 0603 or larger footprints. A real implementation likely
occupies less total board space.
Note that changing components can improve or degrade EVM performance.
4 Recommended Operation Condition
Table 1 provides a summary of the bq51020EVM-520 performance specifications. All specifications are
given for an ambient temperature of 25°C.
Table 1. bq51020EVM-520 Electrical Performance Specifications
Modifications
goes high)
PARAMETER TEST CONDITION MIN TYP MAX UNIT
V
IN
I
AD_EN_sink
I
IN
I
OUT
V
OUT(REG)
f
s
T
J
(1)
The output voltage can be adjusted using V
operation of the EVM.
RECT input voltage range 4.0 10.0 V
Sink current 1 mA
Input current range 1.5 A
Output current range Current limit programming range 1.5 A
Programmable output voltage
Switching frequency WPC 110 205 kHz
Junction temperature 125 °C
(1)
P
= 5 W 4.5 8 V
OUT
resistors. Also the coil needs to change for different voltage for optimal
OUT(REG)
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GND
1800pF
C4
0.068µF
C2
0.068µF
C1
BOOT1
RECTBOOT2
BOOT2
OUT
BOOT1
CLMP1
AD
FOD
VTSB/VIREG
CLMP2
COMM1
AD_EN
/WPG
COMM2
VO_REG
CM_ILIM
TS
CLMP1
0.47µF
C9
0.47µF
C12
CLMP2
COMM2
COMM1
GND
GND
VO_REG
1
2
J5
GND
0.1µF
C19
GND
TS
GND
VTSB/VIREG
TP1
DNP
TP2
DNP
2.00k
R13
DNP
GND
1.50k
R7
RECT
/WPG
GND
GND
0.1µF
C18
150
R2
FOD
TP5
1
2
3
JP1
110
R4
TP4
ADJ
TS
GND
ILIM
FIX
RECT
56.2k
R1
1
2
J3
1
2
J4
1
2
3
JP2
GND
CM_ILIM
High
Low
CM_ILIM
GND
GND
0.1µF
C16
TP3
GND
GND
0.1µF
C6
OUT
GNDGND
AD_EN
Rect
1µF
C17
GND
GND
GND
Out
ILIM
FOD
AC1
AC2
Orange
D2
Green
D1
1
2
3
4
5
6
7
8
9
10
11
J1
1 2
3 4
5 6
7 8
9 10
J2
GND
Q1
CSD75301W1015
OUT
AD
GND
20k
R15
10.0k
R11
5.11k
R16
0.047uF
C3
100pF
C5
10µF
C14
10µF
C15
1µF
C20
0
R3
OUT
0.015µF
C10
0.015µF
C11
0.022µF
C8
0.022µF
C13
3.3µF
C7
1.50k
R20
DNP
Green
D3
DNP
GND
102k
R17
DNP
102k
R14
11.3k
R18
DNP
11.3k
R10
102k
R19
DNP
5.6Meg
R12
27k
R21
DNP
100pF
C22
DNP
GND
PGND
A1
PGND
A2
PGND
A3
PGND
A4
PGND
A5
PGND
A6
AC1
B1
AC1
B2
AC1
B3
AC2
B4
AC2
B5
AC2
B6
BOOT1
C1
RECT
C2
RECT
C3
RECT
C4
RECT
C5
BOOT2
C6
OUT
D1
OUT
D2
OUT
D3
OUT
D4
OUT
D5
OUT
D6
CLAMP1
E1
AD
E2
AD_EN
E3
EN1/SCL
E4
VIREG
E5
CLAMP2
E6
COMM1
F1
FOD
F2
LPRBEN and TERM
F3
EN2/SDA
F4
LPRB1 and WPG
F5
COMM2
F6
VO_REG
G1
ILIM
G2
CM_ILIM
G3
TS
G4
TMEM
G5
LPRB2 and PD_DET
G6
U1
bq51020
2.2µF
C21
200
R9
200
R8
5 K
R5
DNP
500 Ohm
R6
1
2
3
JP3
1
2
3
JP4
TP6
Ext
GND
GND
Hi
Low
Hi
Low
EN1
EN2
102k
R22
5.1V
D4
BZT52C5V1T-7
GND
Equipment and EVM Setup
5 Equipment and EVM Setup
5.1 Schematic
Figure 1 shows the bq51020 schematic.
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Figure 1. bq51020EVM-520 Schematic
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5.2 Connector Descriptions
The connections points are described in the following paragraphs.
5.2.1 J1 – AD External Adapter Input
Power can be provided to simulate an external adapter applied to the receiver in this bq51020EVM-520
(PWR520-002).
5.2.2 J2 – Programming Connector
This connector is populated and is for factory use only
5.2.3 J3 – Output Voltage
Output voltage in wireless power mode up to 1 A; the adapter option is also supported in this PWR520-
002.
5.2.4 J4 –GND
Ground return
5.2.5 J5 – TS/CTRL and Return Connector
External connection for temperature sense resistor, see data sheet for additional information. Not
populated in this spin.
Equipment and EVM Setup
5.3 Jumpers and Switches
The control jumpers are described in the following paragraphs.
5.3.1 JP1– ILIM (FIX or ADJ)
Maximum output current is set by the ILIM pin. In the FIX position, the current is set to a fixed value of R4
plus RFOD. In the ADJ position, current is set by R5. Note that R5 is not populated in this EVM.
5.3.2 JP2 – CM_ILIM
Enables CM_ILIM feature when pulled low and disable when pulled up.
5.3.3 JP3 – EN1 (Low and High)
EN1 pin, set High using external power supply connected to TP6 .
5.3.4 JP4 – EN2 (Low and High)
EN2 pin, set High using external power supply connected to TP6.
5.4 Test Point Descriptions
The test points are described in the following paragraphs.
5.4.1 TP1 and TP2 – AC1 and AC2 Inputs
This are not populated, they can be used for measuring AC voltage applied to the EVM from the receiver
coil.
5.4.2 TP3– Rectified Voltage
The input AC voltage is rectified into unregulated DC voltage (V
); additional capacitance is used to
RECT
filter the voltage before the regulator.
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Equipment and EVM Setup
5.4.3 TP4– ILIM
Programming pin for overcurrent limit protection, pin G2 of the IC.
5.4.4 TP5 – FOD
Input for rectified power measurement for FOD feature in WPC, pin F2 of the IC. TP5 is the FOD pin for
the bq51020.
5.4.5 TP6 – Ext
Connect to 5-V external power supply. Used to pull EN1 and EN2 high. Any voltage level above 7 V may
damage the IC.
5.5 Pin Description of the IC
A1, A2, A3, A4, A5, A6 PGND
D1, D2, D3, D4, D5, D6 OUT
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Table 2. Pin Description
PIN Number (WCSP) bq51020
B1, B2, B3 AC1
B4, B5, B6 AC2
C1 BOOT1
C2, C3, C4, C5 RECT
C6 BOOT2
E1 CLAMP1
E2 AD
E3 AD_EN
E4 EN1
E5 VTSB
E6 CLAMP2
F1 COMM1
F2 FOD
F3 TERM
F4 EN2
F5 WPG
F6 COMM2
G1 VO_REG
G2 ILIM
G3 CM_ILIM
G4 TS/CTRL
G5 TMEM
G6 PD_DET
6 Test Procedure
This procedure describes test configuration of the bq51020EVM-520 evaluation board (PWR520-002) for
bench evaluation.
6.1 Definition
The following naming conventions are followed.
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Test Procedure
VXXX : External voltage supply name (VADP, VTS, V
LOADW: External load name (LOADR, LOADI)
V(TPyy): Voltage at internal test point TPyy. For example, V(TP02) means the voltage at TP02.
V(Jxx): Voltage at header Jxx
V(TP(XXX)): Voltage at test point XXX. For example, V(ACDET) means the voltage at the test
point which is marked as ACDET.
V(XXX, YYY): Voltage across point XXX and YYY.
I(JXX(YYY)): Current going out from the YYY terminal of header XX.
Jxx(BBB): Terminal or pin BBB of header xx.
JPx ON : Internal jumper Jxx terminals are shorted.
JPx OFF: Internal jumper Jxx terminals are open.
JPx (-YY-) ON: Internal jumper Jxx adjacent terminals marked as YY are shorted.
Assembly drawings have locations for jumpers, test points, and individual components.
6.2 Recommended Test Equipment
The following equipment is needed to complete this test procedure:
Power Supplies
• Power Supply #1 (PS #1) capable of supplying 19 V at 1 A is required
• Power Supply #2 (PS #2) capable of supplying 5 V at 1 A is required
• Power Supply #3 (PS #3) capable of supplying 5 V at 1 A is required
Loads
• A resistive load or electronic load that can be set to 5 Ω/1000 mA, 10 Ω/500 mA, and 5 kΩ/1 mA. The
power rating should be 5 W.
Meters
• Two DC voltmeters and two DC ammeters
Oscilloscopes
• Not required
bqTesla Transmitter
• The HPA689 transmitter or equivalent is used for the final test.
Recommended Wire Gauge
• For proper operation, TI recommends 22-AWG wire.
OUT
)
6.3 Equipment Setup
The following items ensure proper equipment setup:
Test Set Up
• The final assembly will be tested using a bqTesla transmitter – provided (HPA689). Input voltage to the
transmitter is set to 19 VDC ±200 mV, with a current limit of 1.0 A.
• Connect power supply to J1 and J2 of the transmitter, HPA689
• Set power supply to OFF
• Place unit under test (UUT) on the transmitter coil
• UUT will be placed in the center of the HPA689 TX coil. Other bqTesla transmitter base units are also
acceptable for this test (ensure the correct input voltage is applied).
Load
• The load is connected between J3-OUT and J4-GND of the UUT
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Test Procedure
• A DC ammeter is connected between UUT and load
• Set the load for 5 Ω/1000 mA
Jumper Settings
• JP1 → ILIM and FIX are shorted
• JP2 → CM_ILM and High are shorted
• JP3 → EN1 and Low are shorted
• JP4 → EN2 and Low are shorted
Voltage and Current Meters
• Connect the ammeter to measure 19-V input current to the transmitter. Connect the voltmeter to
monitor the input voltage at J1 and J2 of TX unit. On UUT a voltmeter is used to measure output
voltage at J3 with ground at J4. Connect the ammeter to measure load current.
RFOD: R6 Set Up
• Connect the ohmmeter between JP5 (FOD) and J4 (GND). Adjust R6 to a 495 Ω reading on the
ohmmeter.
• NOTE: Sometimes the multimeter cannot read the more than 430 Ω from the FOD resistor due to
charged up capacitors in the board. If that happens, use a twizer and short C15 for few seconds, then
measure again.
6.4 Procedure
The following operating procedures are provided at a variety of operating loads:
Turn ON Operation and Operation at 1000-mA Load
• Turn ON transmitter power supply (19 V)
• Transmitter – Verify LED D2 is ON
• UUT – Adjust load current to 1000 mA ±50 mA
• Put the receiver EVM on the transmitter coil and align them correctly
• After 5 seconds verify that:
– Transmitter – Status LED D5 should be green, flashing approximately every 1 second
– The transmitter should beep
– Transmitter – LED D2 still ON
– Receiver – LED D1 is ON
– UUT – Verify that V
– UUT – Verify that the rectified voltage is 5 V to 5.4 V (between TP3 and GND) NOTE: a modulation
signal is present on this voltage every 250 ms and may cause fluctuation in the reading: use lower
value or baseline.
Efficiency Test (1000-mA Load)
• Verify that input current to the TX is less than 500 mA with input voltage at 19 VDC
• Turn OFF the transmitter power supply (19 V)
Turn ON Operation and Operation at 500-mA Load
• Turn ON the transmitter power supply (19 V)
• Transmitter – Verify LED D2 is ON
• UUT – Adjust load current to 500 mA ±50 mA
• Put the receiver EVM on the transmitter coil and align them correctly
• After 5 seconds verify that:
– Transmitter – Status LED D5 should be green, flashing approximately every 1 second.
– The transmitter should beep
– Transmitter – LED D2 still ON
is 4.9 V to 5.15 V (between J3 and J4)
OUT
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