原标题：ST STWBC-WA可穿戴无线充电发送解决方案

　　ST公司的STWBC-WA是用于智能手表和可穿戴的无线充电发送器的数字控制器,最佳控制功率小于3W, VIN范围3V-5.5V,支持USB VIN.功率发送器单元负责控制发送线圈和产生接收单元所要求的正确功率.本文介绍了STWBC-WA主要特性和框图,无线充电架构图,发送器-接收器测试建立图,无线充电器发送评估板STEVAL-ISB038V1T主要特性和电指标,电路图,材料清单和PCB设计图.

　　Digital controller for wireless battery charger transmitters for wearable and smart watches applications

　　The STWBC-WA is STMicroelectronics’wireless battery charger transmitter application optimized for wearable usage.Thanks to its 5 V native supply, the STWBC-WA device is ideal to operate with USB powersupplies.

　　Wireless battery charging systems replace the traditional power supply cable by means of electromagnetic induction between a transmitting pad or dongle (TX) and a battery-poweredunit (RX), such as a smartwatch or sports gear.

　　The power transmitter unit is responsible for controlling the transmitting coil and generatingthe correct amount of power requested by the receiver unit. The receiver unit continuouslyprovides the transmitter the correct power level requested, by modulating the transmittercarrier through controlled resistive or capacitive insertion. Generating the correct amount ofpower guarantees the highest level of end-to-end efficiency due to reduced energy waste. Italso helps to maintain a lower operational temperature.

　　The digital wireless battery transmitter can adapt to the amount of energy transferred by thecoil by modulating the frequency, duty cycles or coil input voltage.

　　STWBC-WA主要特性:

　　 Digital controller for wireless battery chargertransmitters

　　 Optimized for < 3 W applications

　　– Smartwatches and healthcare

　　– Internet of Things (IoT) battery-poweredsmart devices

　　– Remote controllers

　　 Cost effective half-bridge topology withintegrated drivers

　　 Optional full-bridge configuration for 3 Wapplications

　　 VIN range: 3 V to 5.5 V

　　– Supports USB VIN

　　 Active presence detector

　　 Parametric customization via graphicalinterface

　　 2 firmware options:

　　– Turnkey solution for quick design

　　– APIs available for application customization

　　 Peripherals available via APIs

　　– ADC, with 10-bit precision

　　– UART

　　– 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:15 years at 85℃ after 10 kcyclesat 25℃

　　– Data memory: 1 Kbyte true data EEPROM;data retention: 15 years at 85℃ after 100 kcycles at 85℃

　　– RAM: 6 Kbytes

　　 Transmitter reference design:

　　– Evaluation board order code:

　　STEVAL-ISB038V1T

　　– 2-layer PCBs

　　– Active object detection

　　– Graphical user interface for applicationmonitoring

　　– Interoperable with receiver:STEVAL-ISB038V1R

　　 Operating temperature

　　– -40℃ up to 105 ℃

　　 Package

　　– VFQFPN32

　　The STWBC-WA firmware sits on the top of the hardware to monitor and control the correctwireless charging operations.

　　图1.无线充电架构

　　图2.STWBC-WA架构图

　　无线充电器发送评估板STEVAL-ISB038V1T

　　STEVAL-ISB038V1T is the wireless charger transmitter unit component of the STEVAL-ISB038V1 wireless charging reference design for wearable applications. It is based on the STWBC-WA and is designed to transfer up to 1 watt of power to wireless power to devices requiring the use of small coils. It can be modified to deliver up to 3 watts.

　　The STEVAL-ISB038V1 is a wireless battery charger reference design evaluation kit designed for ultra-compact battery operated devices, such as wearable gear, smartwatches, Internet of Things sensors and healthcare devices.

　　The design is optimized for 1-watt wireless power transfer with a half-bridge topology on the transmitter side and with tiny 11 mm and 20 mm coils on the receiver and transmitter sides, respectively. For power transfers up to 3 watts, the design can be modified by using larger coils and a full-bridge configuration on the transmitter.

　　The STWBC-WA transmitter can support a cost-effective half-bridge topology (full-bridge optional) and a powerful software API lets you modify the behavior of LED and general purpose IOs as well as connecting external peripherals or devices like sensors to the design via the on-chip I²C and UART ports.

　　The STWLC04 is designed for 1-watt power transfer based on the Qi protocol, with digital control and precise analog control loops ensuring stable operation. The I²C interface allows a high degree of customization and settings can be stored in the embedded non-volatile memory.

　　图3.发送评估板STEVAL-ISB038V1T外形图

　　发送评估板STEVAL-ISB038V1T包括:

　　To evaluate the STEVAL-ISB038V1T board, ensure you have:

　　•Hardware:

　　− STEVAL-ISB038V1T 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 micro-USB connection in order to use the GUI and to supply the board.

　　•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

　　发送评估板STEVAL-ISB038V1T主要特性:

　　•STWBC-WA based wireless power transmitter− Additional transmitter module compatible with the STEVAL-ISB038V1 reference kit

　　− Cost effective Half Bridge topology with integrated drivers

　　− Optional Full Bridge configuration for 3 W applications

　　− Active presence detector

　　− 2-layer PCB for easy design

　　− Turnkey solution or customizable via APIs

　　− Parametric customization via graphical interface

　　•Full KIT characteristics:− 11 mm coil on Receiver

　　− 20 mm coil on Transmitter

　　− 1 Watt delivered on Receiver side

　　− USB 5 V input

　　− Foreign Object Detection (FOD) optional

　　− Graphical interface for monitoring behavior

　　− Total reference design

　　− RoHS compliant

　　•STWLC04 wireless power receiver− Output voltage: 5 V regulated voltage

　　− Integrated high efficiency synchronous rectifier

　　− Li-Ion/Li-Pol charger functionality

　　− 4-layer PCB for easy design

　　发送评估板STEVAL-ISB038V1T主要电性能表:

　　发送评估板STEVAL-ISB038V1T材料清单: