IdeaZero's Low-Cost Bench Supply Turns USB Power Delivery Into Whatever Voltage You Need

Negotiating a 20V USB Power Delivery connection at one end and spitting out a programmable voltage at the other, this compact PSU delivers.

Gareth Halfacree
5 months agoHW101 / 3D Printing

Pseudonymous maker "IdeaZero" has penned a guide to turning a low-cost DC-DC buck converter into a slick USB Power Delivery (PD) bench-top power supply — complete with configurable output and power monitoring.

"Some time ago, I came across a cost-effective DC-DC buck module equipped with digital voltage control (constant voltage) and a display," IdeaZero writes of the project. "I'm a fan of digital control power supplies as the analog control knobs wear out after prolonged usage. So [I] thought of creating a compact and portable enclosure for the module, using a USB-PD decoy module. This modification would enable its compatibility with various USB-PD smartphone and laptop chargers or power banks."

The buck module in question is the HW-212, a popular and low-cost DC-DC buck converter which includes buttons for on-the-fly power control and a display showing the set voltage and the live current or power draw. This is linked to a USB Power Delivery trigger board, or "decoy module" — designed to negotiate with a USB PD-compatible power supply on its USB Type-C input and output whatever it receives at a pair of power terminals on the other end of the board.

In IdeaZero's bench-top power supply, the USB PD board is set — using on-board DIP switches — to negotiate a 20V supply, which it then passes through to the DC-DC buck converter. Everything is housed in a custom 3D-printed case with a neat bonus feature: an "indicator slide," made from transparent acrylic covered on its faces with aluminum foil, which splits the design in two and acts as a light guide for supply status LEDs.

"While these DC-DC power supply modules may lack precision and accuracy," IdeaZero admits, "they prove [a] beneficial handy DIY solution for testing purposes when we are away from the main bench power supply. Additionally, they serve as a portable backup as a secondary power source for devices such as motors, LED strips, buzzers, repair works, and more."

IdeaZero's full guide is available on Instructables, complete with the STL files for printing the case.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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