Replacing analogue control of a power supply throug digital control with Arduino

It’s a little project in shool and I would like to get some support on it.

I bought a power supply kit (circuit is attached) and would like to control the output dc and current wigh Arduino and digital potentiometers called MCP4131.

I have successfully tested the chips with Arduino to change the brightness of led - it works fine.

The circuit of the power supply is attached.

According to the data sheet of the MCP4131, the max. current on P0A,P0W and P0B is +/- 2.5 mA and max. voltage is VDD + 0.3V.

Now I think about how to connect my Arduino to the power supply, so that I don’t need an extern 5V power adapter for my arduino?

And how should I implement the MCP’s for voltage and current control?

Not at all easy .

The current setting pot is 500 ohms and the lowest value MCP4131 you can get is 5k. Just altering the surrounding components proportionally may not deliver enough current to the LM723 current limit input.

The votage sensing pot has full output voltage applied and floats (ie no part is earthed) . The maximum voltage you can apply to a MCP4131 is 5 volts. Would need considerable circuit rearrangement

I'll think about it.



Pictures embedded.

The way to do a controlled supply is find a regulator that takes a control voltage, and use a DAC to
drive that voltage - but the control pin must be safe to connect to a 5V only circuit, ie an input
referenced to circuit ground.

By the way that circuit diagram is drawn sideways making it impossible to read, euurghh!