Hi all, I would like to use a LM3478 as a constant current supply at 1.0 amps 9 to 18 vdc. I have two ways i would like to do this one is by using a digipot in the voltage divider circuit that feeds the 1.26 volts to the FB pin. The other way I was thinking about is, can I send an output from an analog output pin on a pic to the FB pin directly, of course I would have a shunt and current measuring op-amp that would tell me when my load has reached 1.0 amps. Put another way, can I input a lower voltage then1.26 to the FB pin to increase Vout, then inject 1.26v when the I have satisfied the current requirement? Would that work, why or why not?
-Bill