I intend to build a bipolar, variable, lab power supply (non-switching), say plus and minus 3 to 25 VDC @ 1 to 1.5 amps. The National datasheets for the LM317 regulator series shows such an application, however the output voltage is set for both the positive and negative regulators using a ganged dual pot.
I would like to replace the dual pot with with a device(s) that uses a control voltage (from a microcontroller) to set the output voltage. Where things get fuzzy for me is the complimentary control element for the negative regulator. Any ideas?
Thanks