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