I'm a newbie on analog design . I was hoping someone can give me more info on the attached circuit .
I feel the first op-amp acts as a differential amplifier and the second one I'm confused with the capacitors in feedback path , whether its a filter or integrator / differentiator or they are there just for the impedance ...
I tried measuring on the boards , two versions on the opamp pins , I noticed something like the IC's(LT1630 on different boards same circuit ) giving different output for same inputs . I know opamps try to make both their inputs same , but I cant see how they give different output for same input .
Pin number 3 is a constant dac drive , approx 4.5 Volts . Sense +/- are power supply sense pins .
Also it could be appreciated if some one can tell me a godd practical oriented e-book for gaining more insight on opamps .
The first opamp has no power supply shown (single or dual supply?)
The 2nd opamp has no dc feedback and single supply. Cannot work.
Where does the circuit comes from?
Both op-amps(U18 A and U18 B) in same 8-PIN SOIC. So have same supply as the U18A . Yea , the series cap is reason for my doubt also . Its a working circuit and I have the boards with me . I'm trying to debug it to recreate a similar setup .
The circuit is part of a power supply sense circuit . The output of U18A goes to transistor regulator (voltage) and input to U18B is Sense + and Sense - pins .