USB-C-Powered Bench Power Supply Can Be Used Anywhere
Brian Lough has created a "surprisingly capable" bench supply that only costs $12.
A bench power supply is a standard when it comes to working with electronics. You could buy one, yes. What’s the fun in that? Brian Lough's Portable USB-C Powered Bench Power Supply, a bench supply powered via USB-C Power Delivery, is one of the early simple bench supplies I expect to rain on us soon. For now, one of the upsides here is that it’s a fairly straightforward build, costing only $12.
This build uses the IP2721 IC-based PD decoy module to negotiate with the charger to decide which voltage to take from the PSU. It also contains the ZK-4KX Buck-Boost module, which has the display and controls for the power supply. This module makes it easy to convert the voltage from the PD supply to what’s needed, including higher voltages. Lastly, it features a couple of banana jack sockets, which also work with standard cables and a switch to turn off the voltage to the ZK-4KX.
Ground from the IP2721 module is directly connected to the PSU module’s “IN –“ terminal. VCC of the IP2721 is connected to the switch. Then, the other pin of the switch is connected to the PSU module’s “IN +“terminal. The default behavior has been configured to OFF, and the module’s power limit can be set by accessing the “OPP” option in the configuration setting and using the rotary encoder. The temperature limit can also be changed by switching to the “OTP” option and using the rotary encoder. The default for this is 110C, but 80C minimum is recommended. At these temps, I worry a little about the 3D printed housing.
Pressing the “UI” button once allows the voltage and current limit to be set. Voltage is set using the rotary encoder. Then, pressing the “UI” button again changes the setting to current and using the rotary encoder allows it to be altered. Pressing the “UI” button again exits the menu. The output is enabled in the main menu and by pressing in the rotary encoder. Adjustments can be made to the output while it’s enabled by turning the encoder.
Pressing the “SW” button alters what is being displayed on the screen. This changes the bottom row to Amps, Watts, Amp hours or the enabled time. Pressing and holding the “SW” button changes the top row, which can be altered between voltage out, Voltage In and temperature.
This supply is shown paired with a PD power bank, and I am liking what I see.