Dual Power Supply Design

[sougata]

Hi,

I fried my LAB power supply and really inspired to one controlled by a PIC. I need the following features:

1. Dual Digital Variable +/- 0 - 30 Volts
2. Display of V/I on the LCD (both arms single PIC)
3. Tracking mode

I plan to use the LM350 for its robustness. PWM controlled voltage reference for the Vref. Input of the regulator (with/without digital feedback correction perhaps)

Where I am confused is the negative part of the supply. Measuring the supply ouput is okay but current....? If the opamps are on the PIC board powered by the positive half then common mode voltage is out of range. Level shifting accuracy is also a concern ?

Any insights would be of great help