Theo Heng's PD240W Is a Raspberry Pi RP2040-Powered USB Power Delivery Supply for Motors
USB PD 3.1 with EPR support means up to 48V and 5A can be negotiated — though the current design has only been tested to USB PD 3.0.
Robotics student Theo Heng has designed a compact adjustable power supply for motors that uses a Raspberry Pi RP2040 microcontroller to negotiate up to 48V and 5A from a suitable USB Power Delivery (USB PD) 3.1 power source: the PD240W.
"PD240W [is] an adjustable power supply for motor drives using USB [Type]-C Power Delivery negotiation, supporting up to 240W at 48V 5A," Heng explains of the compact device. "This device is designed to be compatible with USB-PD 3.1 and above. Firmware runs on a Raspberry Pi Pico (RP2040). [It] negotiates Fixed, PPS [Programmable Power Supply] (5–21V programmable), and AVS [Adjustable Voltage Supply] (15–48V EPR [Extended Power Range]) profiles."
The custom PCB inside the 3D-printed housing of the PD240W hosts a Raspberry Pi RP2040, the same 32-bit dual-core microcontroller found on the Raspberry Pi Pico development board. This connects to external flash, a Texas Instruments TPS26750 USB Power Delivery trigger, a TPD4S480 electrostatic discharge (ESD) protection chip, and an Analog Devices LTC7004 high-side MOSFET driver with suitable MOSFETs for driver control. There's a TI INA228 for voltage and current sensing, a choice of connectors for power output, and a 17V buck output with optional mock STO/SBC voltage for motor drive safety circuits.
The user can set the voltage and current to be negotiated via a color LCD with rotary knob — but while Heng believes the device should be able to handle the higher voltage options available from a USB PD 3.1 EPR-compliant supply, delivering up to 48V and 5A for a total of 240W, he admits that it has "currently only been tested for the USB-PD 3.0 standard (up to 20V, including PPS) [—] use at your own risk when testing high-voltage EPR profiles."
Hardware design files, source code, and 3D print files for the housing are all available on GitHub under the permissive MIT license; the current PCB design, however, has the USB data lines reversed, requiring minor rework to correct.
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