Reference design eases USB Type-C power adapters

USB PPS helps to save power, and reduce device-charging times and heat dissipation, contributing also to cut bill-of-materials costs on the device side.

The STEVAL-USBPD27S reference design combines the STM32G071 microcontroller (MCU), which integrates a complete USB Type-C Power Delivery controller on-chip, with the STCH03 PWM controller and TCPP01-M12 USB Type-C protection IC. With this reference design, users can quickly build fast-charging USB power adapters that meet the stringent European CoC version 5 Tier-2 and US DOE Level VI requirements for minimum four-point average efficiency in active mode and standby power below 40mW.

The STM32G071 MCU handles the entire digital control section, including the algorithm to control VBUS on the secondary side as well as ST’s unique and patented algorithm for adaptive synchronous rectification, which enhances energy efficiency. The VBUS-control algorithm meets the USB Type-C Power Delivery and PPS specifications and implements cable-drop compensation for precise control of the supplied voltage. PPS support enables the output voltage to be adjusted in 20mV steps between 3.3 and 11V, as well as current limiting adjustment in 50mA increments, to minimise conversion losses during charging.

As an MCU-based solution, the reference design gives users extra flexibility to implement additional customised application layers and to incorporate ongoing improvements as the USB Power Delivery standard evolves.

The power section of the STEVAL-USBPD27S leverages ST’s highly integrated STCH03 PWM controller, which features built-in high-voltage start-up circuitry, primary-side constant-current output regulation, and advanced power management. Designed for quasi-resonant zero-voltage switching (ZVS) flyback converters, the STCH03 ensures high efficiency, ultra-low standby consumption, and excellent dynamic performance.

The STD7N65M6 MDmesh M6 primary-side high-voltage STPOWER MOSFET delivers extremely high efficiency with optimised switching behavior in hard and soft switching modes.

Finally, the TCPP01-M12 provides ±8kV ESD protection for the USB VBUS and Configuration Channel (CC) lines, meeting IEC 61000-4-2 Level 4. There is also short-circuit protection between the VBUS pins and CC lines and protection to prevent equipment damage if a defective cable is inserted.

Delivered as a turnkey evaluation module in a compact 59x35x21mm outline with power density of 10.2W per cubic inch, the STEVAL-USBPD27S is ready to order now for $95.00.