PROTON pic BASIC Compilers for PIC, PIC24, dsPIC33
Started by kcsl, Nov 12, 2023, 04:53 PM
Quote from: John Lawton on Nov 16, 2023, 05:26 PMInto the inverting input (-)? Yes, I think so, but the op-amp receives negative feedback into the non-inverting input (+) and this works because the action of A1 and Q2 is an overall inversion so this should work as expected.
Quote from: ken_k on Nov 17, 2023, 10:10 AMGood points David and John. David I will run something up in spice. John regarding the op amp, the ability for the inputs to function with both inputs mV from ground is important with this application, some great opamps have a very limited common mode input range. Some opamps even go into phase reversal when input voltages are close to the supply rail or ground!I just had a look, the LM358's common mode range extends to the neg rail so it could be a good choice. It's output goes within 20mV of ground (good for this application) the output high not a problem for this design just add a bit to it's supply voltage. I will see if I have a spice model. BTW John you might be correct about just build and test.
Quote from: david on Nov 18, 2023, 10:48 AMI'm always intrigued by supplies that have large capacitors on the output but adjustable current limit down to low milliAmp level. Instantaneous output currents could be several Amps for a short time before current limit is effective.
Quote from: ken_k on Nov 18, 2023, 09:44 AMJohns circuit is very fast and more configurable, as John stated some parts could be removed and it would still be faster than the one David suggested.