STMicroelectronics – New digital controller for wireless battery-charger transmitters


The STWBC-WA from STMicroelectronics, a digital controller IC for wireless battery-charger transmitters, has been optimised for use in wearable devices.

The STWBC-WA, which has a rated input- voltage range of 3V-5.5V, is ideally suited for operation from the 5V USB power supply which wearable device chargers use. It is suitable for charging applications using less than 3W.

The power transmitter unit is responsible for controlling the transmitting coil and generating the correct amount of power requested by the receiver unit. This ensures the highest possible level of end-to-end efficiency, keeping power losses to a minimum. It also helps the charging system to maintain a low operating temperature.

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


  • Active presence detector
  • Turnkey firmware available
  • 32kbytes of Flash programme memory
  • 1kbyte of EEPROM data memory
  • 6kbytes of RAM
  • Operating-temperature range: 40°C to 105°C


  • Smart watches
  • Wearable devices
  • Internet of Things sensors
  • Healthcare equipment
  • Remote controls

The STEVAL-ISB038V1 is a reference-design evaluation kit for a wireless battery charger. It provides for 1W wireless power transfer, using a half-bridge topology and a 20mm coil on the transmitter side, and an 11mm coil and STWLC04 wireless power receiver on the receiver side.

Orderable Part Number: STEVAL-ISB038V1