I am an Electronic Engineering Student from South Africa and I do not currently own a bench power supply. A decent 0-30v 0-5amp CV/CC power supply can go up to $250 (more than my monthly rent) which is too expensive for me unfortunately.

Therefore, I have decided to create my own power supply.

The power supply is based on the XL4015 DC-DC Buck converter. The power supply is controlled by an Arduino Nano.

The Arduino Nano sends a PWM signal to a DAC, which sends a voltage to the feedback pin of the XL4015. The voltage as well as the current limit is set using a rotary encoder. The Arduino uses a ADC to measure both the voltage as well as the current to fine adjust the PWM output to significantly increase the accuracy of the output. The Voltage, Current Limit and current current is displayed on a OLED display.

Unfortunately I can either only order PCBs in bulk (100+), or single sided in South Africa.

Above is the PCB, design in EasyEDA, with all the components placed. The header pins on the right hand side is where the two DACs (MCP4725) for voltage and current changing as well as the ADC (ADS1115) will be placed.

The PCB layout is as follows:

The GERBER files for the PCB can be found at: https://github.com/40649547/Digital-Power-Supply

• Arduino
• University
• Bench Power Supply