While considering making a constant power DC power supply, I realized that it was quite challenging to come up with a way to multiply DC analog signals. I eventually decided that it’s simply much cheaper and easier to go ahead and use a microcontroller. In this case, a PIC10F322. RA0 and RA2 are used as ADC inputs, and RA1 is used as a PWM output which is passed through a low pass filter to convert it into an analog signal. Finally, RA3 is used to reset the controller if supply voltage drops below an acceptable threshold.
This same platform can really be used for any (0-5)V level two channel analog signal processing that would normally require tricky analog circuits to implement.
Circuit board design files:
Microchip MPLAB X microprocessor programming files for this device: