Reference design accelerates USB Type-C power adapter with PPS support
Programmable power supply (PPS) support in the USB Type-C Power Delivery 3.0 reference design is claimed to accelerate the design of easy to use, compact, and efficient power adapters up to 27W with zero power operation when no cable is connected. The STEVAL-USBPD27S reference design by STMicroelectronics uses USB PPS to save power, and reduce device charging times and heat dissipation. These benefits contribute to cutting the bill of materials costs, adds the company.
The STEVAL-USBPD27S reference design combines the STM32G071 microcontroller, which integrates a USB Type-C Power Delivery controller on-chip, with the STCH03 pulse width modulation (PWM) controller and the TCPP01-M12 USB Type-C protection IC.
Using this reference design, says ST, 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 handles the entire digital control section, including the algorithm to control VBUS on the secondary side as well as ST’s patented algorithm for adaptive synchronous rectification to enhance 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 3.3V and 11V, as well as current limiting adjustment in 50mA increments, to minimise conversion losses during charging.
The microcontroller-based reference design gives users the flexibility to implement additional customised application layers and to incorporate updates as the USB Power Delivery standard evolves, says ST.
The power section of the STEVAL-USBPD27S leverages the integrated STCH03 PWM controller, which features built-in, high-voltage start-up circuitry, primary side constant current output regulation, and advanced power management. The STCH03 is designed for quasi-resonant zero voltage switching (ZVS) flyback converters, with high efficiency and low standby consumption.
The STD7N65M6 MDmesh M6 primary-side high-voltage STPOWER MOSFET which delivers high efficiency with optimised switching behaviour in hard and soft switching modes.
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.
The evaluation module measures just 59 x 35 x 21mm with a power density of 10.2W per cubic inch.
