I would like to build DIY linear bench power supply, with adjustable, regulated output voltage and current limiting functions. The voltage and current regulation will be implemented using analog feedback loops. The functionality of the device requires sensing of the output current in order to:
- Use it in feedback loop to limit current
- Measure output current
Since whole this is to be controlled by microcontroller (voltage and current limit setting, measurement) it means that I need to generate voltage with respect to ground proportional to the current (or not?).
One of the possible solution is to implement high side current sensing using resistor (it is preferable solution due to protection against accidental shorts compering to low side sensing). Examples of the high (and low) sensing circuits can be found in nice app note from microchip.
I am hesitating to use any of the provided solution as that would mean placing two opamps in cascade (opamp for control + current sensing) which may be an issue for circuit stability. Do you have other ideas how high side current sensing could be implemented and be suitable for both analog control and measurement (does not have to be the same circuit)?