The STEVAL-USBPD45C 45 W AC-DC adapter evaluation board architecture is based on a power stage (STEVAL-USBPD45P) implementing a flyback converter with synchronous rectification, and a digital control stage (STEVAL-USBPD45I) designed to control the USB Type-C connector and manage the USB Power Delivery stack and the adaptive synchronous rectification algorithm.
It features a USB Type-C connector and operates as a USB Power Delivery provider with a single source port.
The solution accepts wide input voltage range and delivers 5 V, 9 V and 15 V output voltage profiles, according to the Source Power Rules of the USB Power Delivery specification.
The STEVAL-USBPD45C is the first evaluation board compliant with the latest USB Power Delivery 3.0 specification. The combination of the newest PWM controller STCH03 and the STM32F051 MCU allows meeting the most stringent energy saving regulations, for conversion efficiency and standby power consumption, with further improvement thanks to a dedicated low power control strategy through the MCU. The use of STM32F051 MCU delivers to designers flexibility to follow Power Delivery standard evolution and to implement additional customized application layers.
The microcontroller manages following tasks:
- acts as USB Power Delivery controller, running the ST X-CUBE-USB-PD middleware stack in cooperation with the STUSB1602A USB Type-C controller;
- runs the adaptive synchronous rectification algorithm;
- implements the USB-PD Device Policy Manager.
The X-CUBE-USB-PD middleware stack enables the STM32F051 to act as USB Power Delivery controller, negotiating the power contract between provider and consumer and allowing the solution to correctly deliver the requested Power Data Object, 5 V, 9 V and 15 V output voltage profiles.
The complete application FW, managing both the ST USB PD middleware stack and the synchronous rectification algorithm, is available as STSW-USBPD45CFW binary file.
On the secondary side the MCU controls and directly drives the Power MOSFET STL40N75LF3 for the synchronous rectification, allowing an overall efficiency improvement with a very low external component count. To further improve the overall efficiency, the adaptive synchronous rectification algorithm automatically optimizes the Power MOSFET activation to cope with parametric tolerance and load variations.
The STM32F051 is paired with the certified STUSB1602A USB type-C port controller, enabling the VBUS power path and integrating high voltage protections on VBUS and CC lines.
The STF7N80K5 MDmesh™ K5 primary MOSFET ensures robustness against voltages stress, featuring superior static and dynamic switching behavior.
The ESDA25P35-1U1M high-power Transient Voltage Suppressor (TVS) protects the adapter against destructive electrostatic discharge (ESD) from the USB Type-C connector. This protection also provides surge immunity against electrical overstress (EOS) to prevent damage to the internal circuitry.