原标题：ST STWBC－MCQi 3线圈15W无线电池充电器解决方案

　　ST公司的STWBC-MC是用于无线电池充电器(WBC)发送器(TX)的数字控制器,为WBC使能应用接收器(RX)控制功率传输提供最灵活和有效解决方案,无线充电联盟(WPC)多线圈应用功率高达15W,IN电压3 V-5.5 V主要应用在智能手机,平板电脑和其它电池供电的设备.本文介绍了STWBC-MC主要特性,器件架构图和无线充电系统描述框图以及无线充电器评估板STEVAL-ISB047V1和发送器参考设计板STEVAL-ISB047V1T主要特性,框图,电路图,材料清单和PCB设计图.

　　The STWBC-MC is the digital controller for the wireless battery charger (WBC) transmitters(TX) from STMicroelectronics optimized for the extended power profile (EPP) WirelessPower Consortium (WPC) multi-coil applications up to 15 W.

　　It offers the most flexible and efficient solution for controlling the power transfer to a receiver(RX) in WBC-enabled applications such as smartphones, tablets and other battery-powereddevices that use the electromagnetic induction for recharging.

　　The TX is responsible for controlling the transmitting coil and generating the correct amountof power requested by the RX. The RX continuously provides the transmitter with the correctpower level requested, by modulating the transmitter carrier through the controlled resistiveor capacitive load. Generating the correct amount of power ensures the highest level of endto-end efficiency due to reduced energy losses. It also helps maintaining a lower operationaltemperature.

　　The TX can adapt to the amount of energy transferred by the coil by modulating thefrequency, duty cycle or amplitude of the PWM voltage on the transmitting coil.

　　The STWBC-MC is capable of bidirectional communication with the RX as specified by theWPC 1.2 protocol.

　　The STWBC-MC firmware is specifically designed to take advantage of the hardware to　monitor and control the correct wireless charging operations.

　　STWBC-MC主要特性:

　　 Digital controller for wireless battery chargertransmitter

　　 Multi-coil inductive transmitters optimized for:

　　– Cell phones and smartphones

　　– Tablets and phablets

　　– Charging accessories

　　 Support for Wireless Power Consortium (WPC)

　　EPP applications

　　– Backward compatible with WPC BPP and5W applications

　　 Support for half-bridge topology with DC/DC

　　 VIN range: 3 V to 5.5 V

　　– Supports USB VIN

　　 Active presence detector

　　 Foreign object detection

　　 Q-factor measurement

　　 Parametric customization via GUI

　　 Turnkey firmware solution

　　 Peripherals

　　– 10-bit ADC

　　– UART interface

　　– I2C master fast/slow speed rate

　　– GPIOs

　　 Memory

　　– Flash and EEPROM with read-while-write(RWW) and Error Correction Code (ECC)

　　– Program memory: 32 Kbytes Flash; dataretention: 20 years at 55 ℃ after 1000cycles at 55℃

　　– Data memory: 1 Kbyte true data EEPROM;data retention: 20 years at 55 ℃ after 1000cycles at 85℃

　　– RAM: 6 Kbytes

　　 Transmitter reference design:

　　– Multi-coil EPP topology

　　– 2-layer PCBs

　　– Active object detection

　　– Graphical user interface for applicationmonitoring

　　 Operating temperature: -40℃ up to 105℃

　　 Package: VFQFPN32 5 x 5 mm

　　图1.无线充电系统描述框图

　　The STWBC-MC is a flexible controller that supports a half-bridge coil driver together with aDC/DC controller, which regulates the input voltage of the bridge in order to control the　amount of power transmitter to the receiver. It also controls the selection of the active coil formulti-coil topologies.

　　The digital controller also regulates the half-bridge operating frequency and duty cycle to　further adjusting the amount of power increasing the overall efficiency at the light-load.　It implements the WPC 1.2 protocol, including foreign object detection (FOD) extensions. Anaccurate Q-factor measurement provides enhanced FOD.

　　The STWBC-MC is able to manage both the WPC baseline power profile (up to 5 W) and　extended power profile (EPP).

　　图2.STWBC-MC器件架构图

　　无线充电器评估板STEVAL-ISB047V1

　　15 W 3-coil fixed frequency Qi wireless charger TX evaluation kit based onSTWBC-MC.　The STEVAL-ISB047V1wireless charger evaluation kit includes the STEVAL-ISB047V1T transmitter reference design boardand an STEVAL-WBCDNGV1 USB-to-UART dongle for PC communication.

　　The transmitter is based on a 3-coil, fixed frequency design, with a sepic DC/DC stage supplying a half bridge inverter operatingat 127.7 kHz fixed frequency, for compatibility with proprietary fast charge modes of popular smartphones. The transmitter isdesigned to accept a 15 W, 5 to 20 V input as per the USB type-C™ power delivery specification, or limit the input to 5 W ifsupplied by legacy 5 V USB chargers.

　　The STEVAL-ISB047V1T transmitter is compliant with Qi WPC 1.2.4 specification, and is compatible with all Qi-compatiblereceivers, including mobile phones, and supports resistive and capacitive modulation. The transmitter is capable of Qi EPP bidirectional　communication and is backward compatible with 5W BPP receivers.

　　The STWBC-MC controller monitors and drives the STEVAL-ISB047V1T transmitter, including the digital DC/DC controller thatregulates the transmitted power. The controller supports automatic coil selection based on the best coupling with the receiver,as well as a patented Q-factor measurement for accurate foreign object detection (FOD).

　　You can communicate with the controller via UART, and monitor the behavior of the transmitter on your PC using the STSWSTWBCGUIgraphical interface.

　　图3. 评估板STEVAL-ISB047V1带线圈外形图

　　图4. 评估板STEVAL-ISB047V1底边发送板外形图

　　图5. 评估板STEVAL-ISB047V1框图

　　评估板STEVAL-ISB047V1发送板主要特性:

　　• WPC Qi 1.2.4

　　• Standard Qi 3 coil-FF type transmitter and coil

　　• Qi EPP bi-directional communication

　　• Triple path signal demodulation

　　• Best coupling-based coil selection and presence detection

　　• Coil current and temperature monitoring

　　• Input voltage monitoring

　　• Foreign object detection (FOD)

　　• Quality factor measurement

　　• LEDs for charge status indication

　　• UART connection for user interface and firmware download

　　• SWIM connection for firmware download

　　• 5-20 V power supply

　　• USB-Power Delivery

　　• USB quick charge

　　图6. 发送器参考设计板STEVAL-ISB047V1T电路图(电源)

　　图7. 发送器参考设计板STEVAL-ISB047V1T电路图(SEPIC)

　　图8. 发送器参考设计板STEVAL-ISB047V1T电路图(桥)

　　图9. 发送器参考设计板STEVAL-ISB047V1T电路图(控制器)

　　图10. 发送器参考设计板STEVAL-ISB047V1T电路图(检测)

　　图11. 发送器参考设计板STEVAL-ISB047V1T电路图(解调)

　　图12. 发送器参考设计板STEVAL-ISB047V1T电路图(机械部分)

　　图13. 发送器参考设计板STEVAL-ISB047V1T电路图(USB-PD)

　　图14. 发送器参考设计板STEVAL-ISB047V1T电路图(线圈1)

　　图15. 发送器参考设计板STEVAL-ISB047V1T电路图(线圈2)

　　图16. 发送器参考设计板STEVAL-ISB047V1T电路图(线圈3)

　　图17. 评估板STEVAL-WBCDNGV1电路图

　　评估板STEVAL-ISB047V1材料清单:

　　发送器参考设计板STEVAL-ISB047V1T材料清单:

　　评估板STEVAL-WBCDNGV1材料清单:

　　图中数字对应:

　　1. V Jack

　　2. VIN: L100 directly to C200 C201 and L200

　　3. Vin USB PD

　　4. Supply from J100: connected with capacitors (C100 to C105) and L100

　　5. Vin connection to LDO input

　　图中数字对应:

　　1. TP101: large GND

　　2. All caps connected to GND bottom side with many vias

　　3. GND of LDO with large trace (needed for thermal reasons)

　　图中数字对应:

　　1. Q201 - R206

　　2. L200 & C202 &C203 &C219 & Q201

　　3. Connect L200 – C202-C203-C219 & D200

　　4. DCDC: D200-C206 to C214 and Q300 –Q302

　　图中数字对应:

　　1. High current of GND from Coil : this GND Pow er must be connected between DCDC GND ( C206 to C214) – R Sense (R303& R508) and MOS (Q900-Q1000-Q1100)

　　2. Place many vias near C214 between GND power and GND bottom side　　图中数字对应:

　　1. VDCDC Sheet 64

　　2. GND sheet 67

　　3. VR sense must be very short Q301 R302 & R509

　　4. Bridge node large nets

　　5. Connection COIL bridge node TP1100

　　6. Connection COIL bridge node TP1000

　　7. Connection COIL bridge node TP900

　　8. Bridge node place many vias

　　图中数字对应:

　　1. R201 & C204: very close to D200

　　2. C206 near top of VDCDC

　　3. C207 near C214

　　图中数字对应:

　　1. R400 near pin 28 and 29

　　2. C400 and L400 near pins 29 and 30

　　3. C401-L401-C402 near pins 13 and 14

　　　　图中数字对应:

　　1. C501 – R504 close to U400 net isense

　　2. R507 near U400 net idemod must be protected (no noisy GND or signal)

　　3. VRSENSE (Q301-R302 and R509 ) near current amplifier Q500 and R&C

　　4. Warning: R 508 GND connected to GND on Rsense R302: Do not mix this track with ground plane.

　　5. R508

　　图中数字对应:

　　1. Current demod (C509-R611-R612) closed to U400 pin 12

　　2. Current amplifier U600 near current sensing (Q500)

　　　NTC R409 must be placed near current sensing (Q500)

　　　图中数字对应:

　　1. Bridge driver U300 near MOS Q300 and Q301

　　2. Nets UPBL and DNBL are very noisy: isolate these nets and add GND traces if sensitive nets are closed

　　图31.桥驱动器布局图

　　图32.无线圈连接到PCB顶层图