dm00158917

UM1861
User manual
Qi A11 wireless charger transmitter evaluation board based on
STWBC
Introduction
The following describes the operation of the STEVAL-ISB027V1 Qi A11 wireless power transmitter
evaluation board. The STEVAL-ISB027V1 is a certified reference design based on the Qi A11 wireless
power consortium (WPC) standard version 1.1.2, and supports FOD (foreign object detection).
The transmitter is compatible with all Qi-compatible receivers, such as those already available in Qienabled mobile phones. Receivers with both resistive or capacitive modulation are supported.
In accordance with the Qi A11 topology, the STEVAL-ISB027V1 supports a 5 V input and a full bridge
stage with both frequency and duty cycle control. The STEVAL-ISB027V1 features the STWBC
controller, which integrates all the functions required to drive and monitor the transmitter.
STWBC supports UART connectivity to a PC and thanks to the STEVAL-ISB027V1 graphical interface,
it is possible to monitor the behavior of the transmitter in real-time.
The STEVAL-ISB027V1 reference design provides a complete kit which includes the STWBC, firmware,
layout, graphical interfaces and tools. The layout is based on a cost-effective 2-layer PCB.
This user manual explains the STEVAL-ISB027V1 hardware and software installation, as well as details
on the evaluation of the board and the GUI interface.
Figure 1: STEVAL-ISB027V1 evaluation board
April 2016
DocID027449 Rev 3
1/40
www.st.com
Contents
UM1861
Contents
1
2
3
Getting started ................................................................................ 3
1.1
System requirements ....................................................................... 3
1.2
Package contents............................................................................. 3
Hardware description and setup ................................................... 4
2.1
System block diagram ...................................................................... 4
2.2
STEVAL-ISB027V1 wireless transmitter board ................................ 4
2.3
STWBC pinout and pin description .................................................. 6
Software installation ...................................................................... 9
3.1
STWBC GUI software installation .................................................... 9
3.2
Firmware download with STWBC GUI ........................................... 11
3.3
Firmware erasing with STVP .......................................................... 13
3.3.1
Requirements .................................................................................. 13
3.3.2
Procedure ........................................................................................ 14
4
Evaluation setup equipment ........................................................ 17
5
GUI and evaluation procedure ..................................................... 18
5.1
Efficiency ........................................................................................ 25
5.2
Standby consumption ..................................................................... 25
5.3
Status LEDs ................................................................................... 26
5.4
Oscilloscope screenshots .............................................................. 26
6
Board diagrams ............................................................................ 28
7
Bill of materials ............................................................................. 31
8
Board assembly and layout ......................................................... 34
8.1
Power signals (5 V, GND and LC power node) .............................. 34
8.2
Sensitive signals ............................................................................ 35
9
References .................................................................................... 38
10
Revision history ........................................................................... 39
2/40
DocID027449 Rev 3
UM1861
Getting started
1
Getting started
1.1
System requirements
In order to use the STEVAL-ISB027V1 board with the GUI, a PC with the Microsoft®
Windows® operating system must be used. The GUI (graphical user interface) works with
Microsoft Windows XP® or later and NET Framework 4.
The connection between the PC and the board is made through a USB-to-UART cable.
1.2
Package contents
To be used, the STEVAL-ISB027V1 evaluation board requires the following items:



Hardware:

STEVAL-ISB027V1 board

ST-LINK/V2 in-circuit debugger/programmer with single wire interface module
(SWIM), available for download from www.st.com.

USB to UART interface cable with 3.5 mm jack connection TTL-232R-5V-AJ
Software:

ST-LINK USB driver

STVP programming tool from STMicroelectronics (integrated into STVD tools)

FTDI VCP driver http://www.ftdichip.com/Drivers/VCP.htm

PC GUI installation package
Documentation:

User manual
DocID027449 Rev 3
3/40
Hardware description and setup
UM1861
2
Hardware description and setup
2.1
System block diagram
Figure 2: Block diagram
2.2
STEVAL-ISB027V1 wireless transmitter board
The STEVAL-ISB027V1 board has the following features:








WPC Qi 1.1.2 certified
Standard Qi A11-type transmitter and coil
Resistive and capacitive modulation
Foreign object detection (FOD)
LEDs for charge status indication
UART connection for user interface
SWIM connection for firmware download
5 V power supply
Table 1: STEVAL-ISB027V1 electrical performance
Parameter
Description
Notes and conditions
Min.
Typ.
Max.
Unit
4.75
5
5.5
V
Input characteristics
Input voltage
VIN
Recommended input
voltage
Measured on board
power supply connector
5
IIN
Input current
VIN nominal, IOUT = Max
1.5
Input no-load current
Input standby
current
V
2.5
A
-
mA
0.70
mA
System characteristics
FS
Duty cycle @
205kHz
ηPk
4/40
Switching frequency
Depends on Rx load
110
Duty cycle
modulation
Only for FS= 205 kHz
10
Peak efficiency
VIN = 5 V, P Out Rx= 4 W
DocID027449 Rev 3
205
kHz
50
%
71
%
UM1861
Hardware description and setup
Parameter
Description
Notes and conditions
Min.
Typ.
Max.
Unit
70
%
Input characteristics
η
Full load efficiency
VIN = 5 V, RX_Power= 5
W
Figure 3: STEVAL-ISB027V1 Qi A11 evaluation board
Figure 4: Board reference designators
Table 2: Connector description
Test point reference
Description
J3
UART jack connector used for the GUI
J4
SWIM connector used for download
J5
I2C connector not mounted
DocID027449 Rev 3
5/40
Hardware description and setup
UM1861
Table 3: Test points
Test point reference
2.3
Signal
Description
TP2
DIGIN[2]
Digital input 2
TP3
PWM_AUX/GPIO_2
PWM output or GPO
TP4
LED_RED
Digital output for the red light indicator
TP5
GND
Ground
TP6
GND
Ground
TP7
GPIO_0
Digital output for the green light indicator
TP8
SYMBOL_DETECT1
Symbol detector 1
TP9
SYMBOL_DETECT2
Symbol detector 2
TP10
CURRENT_DEMOD
Symbol detector 3
TP11
POWER COIL +
Connection point for the power coil
TP12
POWER COIL -
Connection point for the power coil
TP13
SUPPLY_GND
Connection point for the power supply ground
TP14
SUPPLY_5V
Connection point for the power supply 5V
voltage
STWBC pinout and pin description
The STWBC is a multifunction device that can support several wireless charging
architectures. The pinout is therefore application specific. This section shows the pinout
used by the STWBC when the Qi A11 configuration is used. Table 4: "Pinout description"
describes the function of each pin in case of turn-key and custom firmwares.
Figure 5: STWBC in Qi A11 configuration
6/40
DocID027449 Rev 3
UM1861
Hardware description and setup
Table 4: Pinout description
Pin n°
Pin name
Pin type
Cust firmware
description
Turnkey firmware
description
1
UART_RX (1)
DI
UART RX link
UART RX link
2
PWM_AUX/GPIO_2 (1)
DO
PWM output or GPO
Not used, must not be
connected to any potential
3
I2C_SDA/DIGIN[4] (1)
I2C_SDA / digital input 4
inactive (internal pull up)
4
(1)
I2C_SCL / digital input 5
inactive (internal pull up)
I2C_SCL/DIGIN[5]
5
DRIVEOUT[3]
DO
Output driver for low side
branch right
Output driver for low side
branch right
6
GPIO_0 (1)
DO
Digital output for the
green light indicator /
General purpose I/O
Digital output for the
green light indicator
7
GPIO_1 (1)
DO
Digital output for the red
light indicator / General
purpose I/O
Digital output for the red
light indicator
8
CPP_INT_3
AI
Symbol detector
Symbol detector
9
CPP_INT_2
AI
Vmain monitor
Vmain monitor
10
CPP_REF
AI
External reference for
CPP_INT_3 (if not used,
must be tied to GND)
External reference for
CPP_INT_3 (if not used,
must be tied to GND)
11
CPP_INT_1
AI
Symbol detector
Symbol detector
12
CPP_INT_0
AI
Symbol detector
Symbol detector
13
VDDA
PS
Analog power supply
Analog power supply
14
VSSA
PS
Analog ground
Analog ground
15
TANK_VOLTAGE
AI
LC tank voltage probe
LC tank voltage probe
16
VBRIDGE
inactive (to be tied to
GND)
inactive (to be tied to
GND)
17
SPARE_ADC (1)
Spare analog input (to be
tied to GND if not used)
Spare analog input (to be
tied to GND)
18
NTC_TEMP
AI
NTC temperature
measurement
NTC temperature
measurement
19
ISENSE
AI
LC tank current
measurement
LC tank current
measurement
20
VMAIN
AI
Vmain monitor
Vmain monitor
21
DRIVEOUT[0]
DO
Output driver for low side
branch left
Output driver for low side
branch left
22
DIGIN[0] (1)
Digital input 0
Inactive (internal pull up)
23
(1)
Digital input 1
Inactive (internal pull up)
DIGIN[1]
24
DRIVEOUT[1]
DO
Output driver for high side
branch left
Output driver for high side
branch left
25
DRIVEOUT[2]
DO
Output driver for high side
branch right
Output driver for high side
branch right
26
DIGIN[2] (1)
Digital input 2
Inactive (internal pull up)
27
SWIM
DIO
Debug interface
Debug interface
28
NRST
DI
Reset
Reset
DocID027449 Rev 3
7/40
Hardware description and setup
UM1861
Pin n°
Pin name
Pin type
Cust firmware
description
Turnkey firmware
description
29
VDD
PS
Digital and I/O power
supply
Digital and I/O power
supply
30
VSS
PS
Digital and I/O ground
Digital and I/O ground
31
VOUT
Supply
Internal LDO output
Internal LDO output
DO
UART TX link
UART TX link
32
UART_TX (1)
Notes:
(1)API
configurable
All analog inputs are VDD compliant but can be used only between 0 and 1.2 V.
8/40
DocID027449 Rev 3
UM1861
3
Software installation
Software installation
In order to download the firmware to the board, the GUI software must be installed. This
software allows also the user to have a complete monitoring of the board.
In case of problem with the board, ST-LINK and STVP software can be installed in order to
erase the flash of the STWBC.
3.1
STWBC GUI software installation
To install the GUI, launch the installer file.
Figure 6: Launch the installer file
To connect the wireless power transmitter board to the PC, a USB-to-UART cable must be
used.
The first screen that will appear is shown in Figure 7: "GUI start screen", where you are
asked to choose your COM Port.
Figure 7: GUI start screen
DocID027449 Rev 3
9/40
Software installation
UM1861
Figure 8: Windows computer management window
If the COM port number is higher than 8, the user needs to use a particular
syntax: \\\\.\\COMx where COMx is the COM port number (see Figure 9:
"Specific COM port selection").
Figure 9: Specific COM port selection
10/40
DocID027449 Rev 3
UM1861
Software installation
Now select from GUI the correct COM port and press the "OK" button.
The GUI is ready to run.
3.2
Firmware download with STWBC GUI
This procedure describes the firmware download through UART using the STWBC GUI.
The Generic GUI includes the possibility to download a firmware through UART.
The download includes 3 files contained into a *.cab file
Here are the different steps to load the board with the firmware:
1.
2.
Power up the board and connect the UART cable
Click on Load FW to board 8 (see Figure 10: "Firmware download with STWBC GUI")
Figure 10: Firmware download with STWBC GUI
1.
Select the CAB file containing the Firmware to download (seeFigure 11: "Firmware file
selection message" and Figure 12: "Firmware file selection")
Figure 11: Firmware file selection message
DocID027449 Rev 3
11/40
Software installation
UM1861
Figure 12: Firmware file selection
1.
Power on the board and keep it powered (see Figure 13: "Power on message")
Figure 13: Power on message
1.
Download in progress (see Figure 14: "Download in progress dos window")
Figure 14: Download in progress dos window
1.
A message indicated the success of the download (see Figure 15: "Download success
message")
Figure 15: Download success message
If the STWBC memory is erased, the sequencing of the procedure is a bit
different. The user should first connect UART cable, then select load FW to
board and power up the board in last step.
12/40
DocID027449 Rev 3
UM1861
Software installation
If the download need to be automatized, the following command can be used, starting from
the STWBC GUI folder: C:\\Program Files (x86)\\STMicroelectronics\\STWBC GUI VersionX>STWBC_Loader.exe -com "COM number" -cab "Firmware name.cab" (see Figure 16:
"STWBC address")
Where:


COM number" is the COM Port used by the STWBC GUI
Firmware name.cab" is the name of the firmware with the .cab extension
Figure 16: STWBC address
If the COM port is > COM8, the user needs to use the syntax \\\\.\\COMx where
COMx is the COM port number.
3.3
Firmware erasing with STVP
This procedure describes the firmware erasing procedure using STVP. It has to be used in
case of problem on the STWBC board (e.g. firmware corruption, updating a firmware older
than release 5.41,...)
3.3.1
Requirements




ST-LINK USB Driver installed.
STVP programming tool from STMicroelectronics installed.
ST-LINK hardware tools (also used on IAR compiler)
Configuration of STVP (see Figure 17: "Configuration of STVP")
Figure 17: Configuration of STVP
DocID027449 Rev 3
13/40
Software installation
3.3.2
UM1861
Procedure
1.
2.
3.
4.
Target power off
Target power on
ST-LINK circuit connected to the computer by USB
Connect ST-LINK - SWIM cable with target. Be very careful to connect the SWIM
cable in the correct way on the transmitter board, see pictures below (white strip
towards the bottom) (see Figure 18: "ST-LINK connection on the board" and Figure
19: "SWIM cable connection (zoomed)")
Figure 18: ST-LINK connection on the board
Figure 19: SWIM cable connection (zoomed)
1.
2.
Launch STVP program
Select STM8AF6166 core (see Figure 20: "STVP core selection")
Figure 20: STVP core selection
14/40
DocID027449 Rev 3
UM1861
Software installation
1.
2.
Do not load any program into Ram area of STVP program: all bits will be erased (load
00 00 00 …)
Transfers the "00 00" into STWBC through the SWIM interface using the appropriate
push-button. (see Figure 21: "STVP download")
Figure 21: STVP download
During the program the STVP tools provides information about:

Wrong device select (see Figure 22: "STVP alert 1")
Figure 22: STVP alert 1
Select “OK” to continue.

Any incompatibility found with the device (see Figure 23: "STVP alert 2")
Figure 23: STVP alert 2
Select “Yes” to continue.
1.
After this operation, the programming procedure starts. At completion, the STVP
informs the user that the program is loaded and verified
< PROGRAM MEMORY programming completed.
> Verifying PROGRAM MEMORY area...
< PROGRAM MEMORY successfully verified.
1.
2.
3.
Exit from STVP
Disconnect SWIM
Power off the STEVAL-ISB027V1 board
DocID027449 Rev 3
15/40
Software installation
UM1861
That IAR Tool chain can also be installed for firmware compilation and download.
16/40
DocID027449 Rev 3
UM1861
4
Evaluation setup equipment
Evaluation setup equipment
Here is the block diagram of the setup configuration for the testing
Figure 24: Measurement setup
Board is powered with a power supply set to 5 V / 2 A.
An electronic load able to draw 5 W is connected on the receiver output.
Voltmeters and ammeters to measure input and output currents and voltages.
GUI is installed on the PC which is connected to the board thanks to UART connector.
Oscilloscope to monitor mainly the power node voltage and the symbol detection signals.
Figure 25: UART connection
DocID027449 Rev 3
17/40
GUI and evaluation procedure
5
UM1861
GUI and evaluation procedure
To install the GUI and connect the evaluation board, please refer to chapter 3.1 "GUI
software installation".
The STWBC GUI offers complete monitoring of STWBC operation.
The main screen gives the status of the transmitter state and Qi receiver information (see
Figure 26: "Object detected and charge in progress").
Figure 26: Object detected and charge in progress
The STWBC GUI can also display the Rx to Tx communication protocol errors which is
helpful for system debugging (see Figure 27: "Protocol window").
18/40
DocID027449 Rev 3
UM1861
GUI and evaluation procedure
Figure 27: Protocol window
On top of main state machine behavior, the user can monitor STWBC internal variables
such as the operating frequency, the Rx reported power, the coil temperature, etc. (see
Figure 28: "Monitor window")
DocID027449 Rev 3
19/40
GUI and evaluation procedure
UM1861
Figure 28: Monitor window
The STWBC GUI provides the interface to the STWBC tuning parameters. The userfriendly interface allows efficient system adjustment (frequencies, duty cycle, thresholds).
The STWBC GUI provides ways to load/store parameters from/to the computer disk (see
Figure 29: "Parameter window").
There are 2 levels of protection for the parameters:


20/40
Level 0: parameters can be modified without protection
Level 1: more critical parameters that can be modified with caution. Click on "unlock
param" button to be able to modify them. This can lead to system malfunction or
generate behaviors incompatible with Qi standard. So the user should be very
cautious when modify them.
DocID027449 Rev 3
UM1861
GUI and evaluation procedure
Figure 29: Parameter window
New parameters can be tested straight away by clicking the button "push to target". The
modified parameters are not colored anymore (see Figure 30: "Parameters modification").
DocID027449 Rev 3
21/40
GUI and evaluation procedure
UM1861
Figure 30: Parameters modification
As mentioned in firmware download chapter, the STWBC GUI embeds the interface to the
STWBC FW downloader (which uses UART connection).
The STWBC GUI embeds tools allowing the generation of tuning parameters binary file and
the modification of FW package to insert custom tuning parameters file.
The GUI allows us to change the parameters for producing a new cab which can then be
used to program a batch of new boards.
In order to do this, the user should first dump the parameters to a bin file. Prior to this, be
very careful to press the "push to target" button! (see Figure 31: "Dump to bin file button"
and Figure 32: "Bin file backup")
22/40
DocID027449 Rev 3
UM1861
GUI and evaluation procedure
Figure 31: Dump to bin file button
Figure 32: Bin file backup
Then the user should select the firmware CAB file to be patched (see Figure 33: "CAB file
patch button" and Figure 34: "CAB file selection").
DocID027449 Rev 3
23/40
GUI and evaluation procedure
UM1861
Figure 33: CAB file patch button
Figure 34: CAB file selection
The patched firmware with the new tuning parameters is then generated and can be loaded
using the standard procedure (refer to Section 3.2: "Firmware download with STWBC
GUI").
24/40
DocID027449 Rev 3
UM1861
5.1
GUI and evaluation procedure
Efficiency
High efficiency of more than 70 % can be achieved with the QIA11 STEVAL-ISB027V1
reference board.
Efficiency measurements are done with a QiA11 Power receiver. QiA11 Transmitter is
supplied at 5 V and receiver voltage level is also 5 V.
Pout is the output power measured really at the output of the receiver itself (not only
rectifier output) and Pin is the input power.
Efficiency is measured with the below set up configuration:
Figure 35: Efficiency set up
Below are the typical efficiency performances. Efficiency = Pout / Pin:
Figure 36: Efficiency performances
5.2
Standby consumption
In Standby, when supplied at 5 V, very low power consumption is achieved.
In this mode, device detection is still ensured; power consumption is reduced down to 700
µA in average. STEVAL_USB027V1 reference board can demonstrate a low standby
power of only 3,5 mW.
To measure such low power consumption, UART cable must be unplugged.
DocID027449 Rev 3
25/40
GUI and evaluation procedure
5.3
UM1861
Status LEDs
The LEDs status gives the state of the charge:






5.4
Green Blinking: power transfer in progress
Green Steady state: the charge is complete
Red blinking: an error has been detected. It includes bad end of charge like battery
fault, over voltage, over current….
Red Steady state: the transmitter remains stuck until the receiver is removed, as
mentioned in the Qi standard (power transfer stopped three times in a row due to
amount of power not provided to the receiver, End Power Transfer due to
Reconfigure, No Response code, FOD detection after 3 attempts)
Red and Green blinking once at startup: a watchdog reset occurred
Red and Green Steady state: Firmware / STWBC chip mismatch
Oscilloscope screenshots
Below are some examples of waveforms that can be monitored on oscilloscope during
power transfer.
Figure 37: Power node switching and peak voltage demodulation
26/40
DocID027449 Rev 3
UM1861
GUI and evaluation procedure
Figure 38: Power node switching and current demodulation
DocID027449 Rev 3
27/40
Board diagrams
6
UM1861
Board diagrams
Figure 39: STEVAL-ISB027V1 circuit schematic (1 of 3)
28/40
DocID027449 Rev 3
UM1861
Board diagrams
Figure 40: STEVAL-ISB027V1 circuit schematic (2 of 3)
DocID027449 Rev 3
29/40
Board diagrams
UM1861
Figure 41: STEVAL-ISB027V1 circuit schematic (3 of 3)
30/40
DocID027449 Rev 3
UM1861
7
Bill of materials
Bill of materials
Table 5: QiA11 bill of material
Ref.
Part / value
Volts/
Amps/
Watts
Type
Tolerance
Package
Manufacturer
Notes
C1, C2
10nF
50V
Ceramic
10%
C0402
Murata
CAP CER 10nF 50V
X7R 0402
C3
470pF
50V
Ceramic
15%
C0402
CAP CER 470PF 50V
X7R 0402
C4, C5
6.8nF
50V
Ceramic
15%
C0402
CAPR 6.8NF 50V X7R
0402
C7, C8
100nF
50V
Ceramic
15%
C0402
CAP CER 100nF 50V
X5R 0402
C9, C17
47µF
10V
Tantalum
10%
C+TAJ-D
C10 C11
C16 C29
10nF
50V
Ceramic
15%
C0402
CAP CER 10nF 50V
X7R 0402
Multilayer ceramic
capacitors
GRM31C5C1H104JA0
1L, 0.1µF, 50V DC,
C0G, package 1206
Kemet
CAP TANT 47µF 10V
10% SMD_D
C12 C13
C14 C15
100nF
50V
Ceramic
5%
C1206
C18 C20
C21 C24
C25
100nF
25V
Ceramic
15%
C0402
CAP CER 100nF 25V
X5R 0402
C19
1µF
16V
Ceramic
10%
C0402
CAP CER 1UF 16V
X5R 0402
C22
100pF
50V
Ceramic
5%
C0402
CAP CER 100pF 50V
COG 0402
C26
1nF
6.3V
Ceramic
15%
C0402
CAP CER 1nF 6V3
X5R 0402
C27
47pF
6.3V
Ceramic
15%
C0402
CAP CER 47pF 6V3
X5R 0402
C30
1nF
50V
Ceramic
15%
C0402
CAP CER 1nF 50V
X5R 0402
C31 C32
100pF
50V
Ceramic
5%
C0402
CAP CER 100pF 50V
X5R 0402
C33
33nF
50V
Ceramic
15%
C0402
CAP CER 33nF 50V
X7R 0402
D3
6.2V
Zener
BZX84C6V
2
Fairchild
ZENER REGULATOR
SOT23
D4
RED
LED
LEDC0603_RED
Wurth
Elektronik
150060RS75000
D5
GREEN
LED
LEDC0603_GRE
EN
Wurth
Elektronik
150060VS75000
D6, D7
BAV99W
Diode
BAV99W
DocID027449 Rev 3
Murata
Double diode high
speed switching diode
31/40
Bill of materials
UM1861
Ref.
Part / value
J3
Stereo
Volts/
Amps/
Watts
Type
Tolerance
Jack, audio
Package
Manufacturer
Notes
CONN_JAC
K_35RASM
T2BHNTRX
Digi-Key
SC1489-1-ND
J4
SWIM_CONN
Header
HE14-4
Molex
MOLEX - 90121-0764 EMBASE 1 RANGEE
90 DEGRES COUDE 4
VOIES
Q5, Q6
BC847CDW1T1
G
Transistor
BC847CD
W1T1GSOT363
ON
Semiconductor
XSTR,GEN PURP,dual
NPN,45V,100mA,225m
W,SOT-363
Q7, Q9
Q11
Q12
BC847BPDW1T
1G
Transistor
BC847CPD
W1T1GSOT363
ON
Semiconductor
XSTR,GEN PURP,dual
NPN/PNP,45V,100mA,
225mW,SOT-363
R1, R15
R16 R44
R45
1K
CMS
5%
R0402
RES 1KΩ 5% 1/16W
0402 SMD
R2, R17
R48 R61
R62
1M
CMS
5%
R0402
RES 1MΩ 1/16W 5%
0402 SMD
R3
150K
CMS
5%
R0402
RES 150KΩ 5% 1/16W
0402 SMD
R4, R59
0R
CMS
5%
R0402
RES 0Ω 5% 1/16W
0402
R5, R10
R11
33K
CMS
5%
R0402
33KΩ 5% 1/16W
R12 R13
R19 R30
R35 R36
R41 R46
R47 R49
100K
CMS
5%
R0402
RES 100KΩ 5% 1/16W
0402 SMD
R14
2.2K
CMS
5%
R0402
RES 2.2KΩ 1/16W 5%
0402 SMD
R22
0.022R
CMS
2%
R0805
RES 0.022Ω 2%
R24
270NH
COIL
5%
L0402
R25
220K
CMS
1%
R0402
RES 220KΩ 1% 1/16W
0402 SMD
R26
180K
CMS
5%
R0402
RES 180KΩ 5% 1/16W
0402 SMD
R27 R29
R58
10K
CMS
5%
R0402
RES 10KΩ 5% 1/16W
0402 SMD
R31
47K
CMS
1%
R0402
RES 47KΩ 1% 1/16W
0402 SMD
R34
1K
Ferrite
25%
L0402
32/40
DocID027449 Rev 3
Wurth
Elektronik
Murata
744784227A
FERRITE BEAD1K
0.2A 0402
UM1861
Bill of materials
Volts/
Amps/
Watts
Ref.
Part / value
Type
R38
50K
Thermistance
R39 R40
1.8K
CMS
R51
330R
CMS
Tolerance
Package
Manufacturer
Notes
DkF503B10
Temperature
measurement probe
assemblies
5%
R0402
RES 1.8KΩ 1/16W 5%
0402 SMD
5%
R0402
330RΩ 5% 1/10W
R52
22K
CMS
5%
R0402
RES 22KΩ 1/16W 5%
0402 SMD
R55 R56
R57
470K
CMS
5%
R0402
RES 470KΩ 5% 0402
R60
470R
CMS
5%
R0402
RES 470Ω 5% 1/16W
0402
FDS8858CZ
Power
MOSFET
U1 U2
Recommended
Part
STS8C5H30L
or
STL40C30H3LL
SO-8
Fairchild
Dual Power MOSFET
N-channel 30, 0.018Ω,
8A, P-channel 30V,
0.045Ω, 5A
SO-8
Power
MOSFET
or
PowerFLAT
5x6
Dual Power MOSFET
N&P Channel, 8.6A,
30V, 0.0205Ω
ST
or
Dual Power MOSFET
N-channel 30, 0.019Ω,
10A, P-channel 30V,
0.024Ω, 8A
U3
STWBC
Digital
controller
QFN32
ST
Digital controller
U4
LMV931
Op amp
SC70-5
TI
Single Op amp,
1.5MHz, 1.8V, rail-torail, SC70-5
Power
coil
WE 760308111
Wireless
charging coil
53.3 x 53.3
mm
Wurth
Elektronik
Tx coil 1 layer 6.3 µH
13A Qi A11
Polycarbonat
e Cover
64 x 55 x 2
mm
Plastic
cover
DocID027449 Rev 3
Coil cover, thickness
2mm
33/40
Board assembly and layout
8
UM1861
Board assembly and layout
The evaluation board has been designed using a low cost 2-layers PCB with all the
components on the top side. The test points allow the user to evaluate the STWBC solution
with probes. In addition, UART is accessible through a 3.5 mm jack connector and SWIM is
routed to a header connector.
Figure 42: Board assembly
The evaluation board can be divided in several main blocks.
Here is the placement:
Figure 43: Evaluation board placement
In order to ensure good behavior of the board, some design rules need to be respected
8.1
Power signals (5 V, GND and LC power node)
5 V power signal is shared in 2 branches:
34/40
DocID027449 Rev 3
UM1861
Board assembly and layout


One connected to the small ferrite bead for the digital side
The other one connected with large track to the driver and the pre driver
GND is shared in 2 areas:


Power GND which is relative to the gate drivers, the full bridge and Rsense
connections
Digital GND which is relative to all the other blocks including STWBC, current
demodulator, current sense measurement
On each GND branch, a tantalum capacitor is placed for decoupling.
As the current flowing into the board can be huge, many vias must be used in order to
route the 5 V and the Power GND from top to bottom.
Large track or plane should be used for power GND, power 5 V, VRSENSE and LC power
node.
Figure 44: GND and 5 V layout
8.2
Sensitive signals
SYMBOL_DETECT1 and SYMBOL_DETECT2 are connected to comparator inputs and
are used for peak detection (demodulation). So the layout must be clean on order to avoid
any coupling.
DocID027449 Rev 3
35/40
Board assembly and layout
UM1861
Figure 45: Symbol_detect analog input signals routing
For the current demodulation circuit, the information is picked up from the ISENSE circuitry.
Then the information is amplified and sent to the STWBC through an analog input
(CURRENT_DEMOD). Short tracks should be used also to avoid any coupling.
Figure 46: Current_demod analog input routing
ISENSE is the image of the current flowing into the full bridge and is connected to an ADC
input. This is part of the PID algorithm, thus it should be routed carefully.
36/40
DocID027449 Rev 3
UM1861
Board assembly and layout
Figure 47: ISENSE analog input routing
UPBL/R and DNBL/R (highlighted in yellow) are the PWM coming from the STWBC and
driving the full bridge. Those signals are quite noisy and must be isolated from signals
going to comparators. They should be routed close to insensitive tracks or some GND
guard lines should be added.
Figure 48: UPBL/R and DNBL/R routing
DocID027449 Rev 3
37/40
References
9
References


38/40
UM1861
Datasheet: STWBC - Digital controller for wireless battery charger transmitters with
multistandard Qi, PMA and wearable support
Data brief: STEVAL-ISB027V1 - Qi A11 wireless charger transmitter evaluation board
based on STWBC
DocID027449 Rev 3
UM1861
10
Revision history
Revision history
Table 6: Document revision history
Date
Revision
Changes
06-Mar-2015
1
Initial release.
25-May-2015
2
Updated:
- Section 3: Software installation
Added:
- Section 8: Board assembly and layout
28-Apr-2016
3
Updated:
- U1 and U2 Ref. value on Table 5: "QiA11 bill of
material"
DocID027449 Rev 3
39/40
UM1861
IMPORTANT NOTICE – PLEASE READ CAREFULLY
STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, enhancements, modifications, and
improvements to ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST
products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order
acknowledgement.
Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance or the
design of Purchasers’ products.
No license, express or implied, to any intellectual property right is granted by ST herein.
Resale of ST products with provisions different from the information set forth herein shall void any warranty granted by ST for such product.
ST and the ST logo are trademarks of ST. All other product or service names are the property of their respective owners.
Information in this document supersedes and replaces information previously supplied in any prior versions of this document.
© 2016 STMicroelectronics – All rights reserved
40/40
DocID027449 Rev 3
Similar pages