Hello,
My product requires a voltage-controlled, current-limited power supply and for a number of years I have used various switcher chips with an op-amp to feed back a current sense voltage to the feedback pin. For the last couple of years I have been using an LM22680, but I seem to get variable results board to board. (Output voltage not consistent)
I supply my circuit with an off the shelf 24 VDC switching power supply and the idea is to drive a variable load at a maximum of 1 amp. I have used WebBench for the different circuits that I have used.
In my application, the output voltage can be anywhere between 9 and 21 volts. The key is to drop the output voltage to limit the current to1 amp.
Three questions: 1) Am I taking the right approach to meet my application parameters?
2) If so, why are the LM22680's providing varying output voltages from board to board with the same load conditions?
3) Is there a better solution I should pursue? I have used an LM25010 in the past, but the 1.25 amps proved to be too much current. Would it work in conjunction with the op-amp feedback circuit? (According to the datasheet, their is a ripple voltage requirement at the feedback pin, that may not be provided by the op-amp.)
Thank you!
Craig