The STWBC2-HP from STMicroelectronics is a Digital Controller for wireless battery charging transmitters specifically designed to support the WPC 1.3, Qi BPP (Baseline Power Profile) and EPP (Extended Power Profile) applications from 5 to 15 W. It is an SiP (System-in Package) that integrates an STM32 microcontroller and an application-specific front-end die. This controller is responsible for controlling the transmitter coil and generating the required amount of power requested by the Rx coil. It generates and controls the relevant PWM signals using a PWM machine that provides a time-domain resolution of 1.47 ns. The front-end die consists of a 40 MHz PLL and a 17-step DLL to achieve this resolution. The front-end die also includes specific registers and an SPI interface with the microcontroller, an output mux for analog signals to the STM32 ADC and GPIOs for digital signals to the STM32’s core.
The STWBC2-HP supports various communication interfaces such as UART, SPI, (up to 28 Mbits/s), I2C (up to 1 Mbit/s) and up to 8x GPIOs. It also integrates peripherals like low-side differential current sensor and Q-factor driver. This controller is available in a surface mount package that measures 8 x 8 mm and is ideal for use in battery-powered mobile devices.