OPEN Power: A Simple Constant Power Supply with Variable Voltage

While there are a ton of power supply options on the market to handle most every project need, you can still build your own using a simple breadboard and a hand full of parts. Building a better power supply is a great endeavor that is always being undertaken by many engineers and makers — including John Loeffler, who is looking to design three prototypes.

Loeffler’s Prototype 1 Simple Constant Voltage Power Supply came about, as he didn’t have enough funds to buy his own lab bench PSU. It’s a simple enough design that features a variable from 0.6V up to 12V, offers 3V and 5V rails, and is powered via a micro USB port. The prototype even has voltage indication using comparators and an LED array.

On the mechanical side, the Prototype 1 comes with headers for both voltage rails, allowing for secure connections, along with a series of MIC5225 (150mA) regulator chips to address the switch mode voltage output. As mentioned earlier, the PSU includes voltage regulation, which is done through an adjustment knob on top of the board, with the variable ranges indicated through LEDs. This is a handy feature to have, especially when utilizing the board for more than one project.

While Loeffler’s first prototype isn’t exactly a B&K Precision 1788 Lab Bench PSU, it does what it is designed to do — provides variable power in a breadboard setting. With that in mind, Loeffler is still at the drawing table fleshing-out designs for his other two prototypes; however, he states all of them will have micro USB ports for power/charging lithium-ion batteries, and load sharing capabilities.