Vincent "CentyVin" Nguyen's PPSTrigger Board Provides Easily-Adjustable USB Power Delivery
Just turn the potentiometer and connect your Programmable Power Supply-capable USB adapter to pick an arbitrary voltage.
Electrical engineer Vincent "CentyVin" Nguyen is working on a "much simplified" board which aims to lower the barrier to entry for powering your projects through the USB Power Delivery (USB PD) and Programmable Power Supply (USB PPS) standards — negotiating arbitrary voltages set via a potentiometer.
"PPSTrigger Board [is] a much simplified USB-C PD and PPS trigger board," Nguyen explains of the project, which builds on his work with the earlier PicoPD trigger — based on the Raspberry Pi RP2040 and Diodes Incorporated AP33772. "[It will] allow users to select arbitrary voltage from PPS-capable power brick via potentiometer."
The USB Power Delivery (USB PD) standard was announced back in 2012, offering the ability for compatible devices to negotiate more than the usual 5V at 3A available from a USB Type-C port — not only asking for more current but also negotiating higher voltages, up to 5A at 48V in the USB PD 3.1 standard. The third revision also brought with it an extension, Programmable Power Supply (PPS), which allowed the negotiated voltage to be adjusted in steps as low as 20mV rather than discrete jumps between defined levels.
It's PPS which Nguyen's trigger board uses to provide a highly-adjustable regulated power output to arbitrary devices — not by requiring any complex programming or changes in device firmware, but by simply turning an onboard potentiometer until the output across the board's screw terminals is at the voltage level you need.
Jumpers are provided on the board to lock the board at 5V, 9V, 12V, 15V, or 20V outputs, or to allow use of the potentiometer — which is read during the board's boot-up process, negotiating a voltage set by its position once then ignoring any adjustments until the next time the board is booted.
"[A] 15 min stress test at 20V 5A showing that the board temperature rises to 62°C [143.6°F] with the board in still air," Nguyen writes of tests carried out on prototype boards. "This is within the working temperature (85°C) of all ICs on the boards."
Nguyen plans to release a small volume run of the PPSTrigger boards on Tindie in the near future; more information is available on his Hackaday.io page.
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