I need to find a op-amp that will handle the high input voltages that my circuit requires. I'm not real familiar with them and not sure how to read their datasheets. I do have a LM741 but it looks like it can only handle +/- 15v. I need at least +/- 60v I think, but I have include the schematic that I used to test with. U1 is just LTSpice's ideal single-pole op-amp. Any suggestions on a particular op-amp or what I need to be looking for would be greatly appreciated.
Edit
I'm trying to use Vout to turn on the gate of a PMOS which is switching a variable voltage from a boost converter. V2 will come from boost converter and V1 will be what I subtracting from V2 so that the PMOS will cut on. The PMOS will be on when Source = Vout and off when Source = Source. The second schematic is the boost converter and the current configuration which uses a voltage divider to control the gate voltage, but I'm concerned that PMOS will not turn all the way on when the voltage is lowered all the way to 12v. I think that Vgs will just be to small using a voltage divider.
- M2 is the PMOS
- M3 is a NMOS used to control the voltage divider.
- The two signals will be coming from Micro Controller.
Best Answer
I apologize for quoting comments from the OP rather than taking quotes directly from the question but it appears to me he is clearer in the his requirements in his comments.
Why don't you use a zener diode like this: -
If you then want to process the signal and you think that 50V is too high then the 4k7 can be made a potential divider such as a 1K and a 3k9. This will reduce the 50V to 10.2V and the 2V to 0.408V.
This won't be a perfectly accurate way of subtracting the voltage but you haven't said how accurate this has to be. You can get "zeners" that are very accurate in the form of shunt regulators - they only need a few tens of microamps to work.