STMicroelectronics – Digital controller for wireless battery charging supports 15W applications


The STWBC-EP from STMicroelectronics, is a digital controller for wireless battery charger transmitters which enables implementation of the Extended Power Profile (EPP) in Wireless Power Consortium (WPC) 1.2-certified applications supplying up to 15W.

The STWBC-EP offers the most flexible and efficient solution for controlling power transfer to a wireless power receiver in smartphones and tablets and other battery-powered devices that use electromagnetic induction for recharging.

In these applications, the STWBC-EP is responsible for controlling the transmitting coil and generating the amount of power requested by the receiver. The receiver continuously provides the transmitter with a signal indicating the power required, by modulating the transmitter carrier through the controlled resistive or capacitive load.

The STWBC-EP’s accurate control of the amount of power supplied means the charger system can achieve high end-to-end efficiency by keeping energy losses to a minimum. It also helps the system to maintain a low operating temperature.

The transmitter can alter the amount of energy transferred by the coil by modulating the frequency, duty cycle or amplitude of the PWM voltage on the transmitting coil. The STWBC-EP is capable of bi-directional communication with the receiver as specified by the WPC 1.2 protocol.


  • Backward-compatible with 5W WPC 1.1 applications
  • Input-voltage range: 3.0V to 5.5V
  • Active presence detector
  • Foreign object detection
  • Q-factor measurement
  • Parametric customisation via GUI
  • Turnkey firmware solution
  • Transmitter reference design is WPC Qi 1.2.3-certified


  • Wireless chargers

The STEVAL-ISB044V1 evaluation kit includes STWBC- EP firmware, a graphical interface for debug, schematics, layout files and a bill-of-materials.

Orderable Part Number: STEVAL-ISB044V1