USB PD Breadboard Power Supply - Updates!

Apr 30

In this video, I show some updates regarding my USB PD breadboard power supply. Some viewers pointed out some things that could be improved, so I implemented them.

Updates and fixes

There are three big changes as compared to the older version (v1.0) of the board. First, I added a 1M resistor between the shield of the USB-C connector and the ground. It is not a super big improvement or upgrade, but since I include this in all my other designs, I decided to add it here as well. Then, I also fixed a typo on the backside of the PCB. Previously, I wrote “USD PD Decoy”, which is obviously wrong, and I meant “USB PD Decoy”. Then, I also made a small improvement based on a viewer’s feedback on the switch and how the resistors are connected to the switch. In the old design, it could occur that if the switch, for some reason, were damaged and it would become an open circuit, or if the user would put it in the middle where there is no contact made by the switch, the regulator would go to an undefined state. To fix this, a resistor (R7) is constantly connected to the feedback of the regulator, which defines a default output voltage (5 V). When the switch is switched to the other position, R8 would be connected in parallel with R7, which would drop the overall resistance to 23.3k, which would then set the regulator’s output voltage to 3.3 V. Probably, it would be safer to make 3.3 V the default voltage. In that case, by default, the 23.3k resistor would be connected to the feedback. Probably in the next iteration of the board, I will implement this switching.