Dual Channel DC Power Supply

This project is a simple, dual channel, linear power supply using a PIC microcontroller to display voltage and current. Instantaneous current is measured using a MAX4172 high side current monitor, so there is no error due to voltage drops across a low-side sense resistor. The ADS1258 ADC provides the ability to read the external reference voltage, thereby allowing a ratio-metric calculation to be performed. This alleviates the requirement for a highly accurate reference.

Current is limited in software - the PIC reads the ADC, and if the current exceeds a preset value, the PIC shutdowns the regulator for a period of time.

External DC power is sourced from a HP printer adapter, capable of supplying 32V DC at 2A, part number 0957-2262.

PIC and ADC board:
Regulator board:
Internal wiring:
PIC and ADC board attached to LCD:
Power supply board attached to regulators:

Last update: 18 April 2015
© Steven J. Merrifield