STWBC2-HP Inductive Wireless Charger Power Transmitter

STMicroelectronics' STWBC2-HP is a digital controller specifically designed for developing Qi-certified wireless power TX applications. The STWBC2-HP is a SiP with an STM32™ microcontroller and an application-specific front-end die. Specifically, the STM32G071 is the microcontroller embedded in the STWBC2-HP.

The STWBC2-HP can drive the DC/DC stage and the half- or full-bridge inverter stage of a generic Qi wireless battery charging TX. It generates and controls the relevant PWM signals using a PWM machine capable of 1.47 ns resolution. To achieve that, the front-end die includes a 40 MHz PLL and a 17-step DLL. The STWBC2-HP front end is capable of working from any DC voltage in the range of 4.1 V to 24 V and embeds:

• 3x half-bridge drivers capable of driving both the FB inverter or the DC/DC MOSFET
• 2x PWM outputs for external gate drivers
• 2x LED/speaker drivers
• 3.6 V / 5 V monolithic buck DC/DC to supply the analog portion of the die
• 3.3 V LDO to supply the STM32
• 1.8 V LDO to supply the core
• 6 V to 9 V voltage doubler to supply the gate drivers
• Resonant tank current, voltage, and phase sense circuitry and Q-factor driver
• USB D+/D- external interface pins for USB PD

The front-end die also includes specific registers and a serial peripheral interface (SPI) with the STM32, in combination with an output mux for analog signals to the STM32 ADC, and GPIOs for digital signals to the STM32 core. The STM32 microcontroller embeds an Arm® Cortex®-M0+ CPU with up to 128 k Flash memory and up to 32 k of SRAM with parity check with a clock frequency of up to 64 MHz. It also embeds a 12-bit, 0.5 μs ADC and provides UART, I²C, SPI, and GPIOs. The STM32G071 embedded in STWBC2-HP also provides two 12-bit DACs and a USB PD controller.