Hello,
Actually I refer a microchip document AN1444, in this document (document page no 15) I studied topic “AC CURRENT SENSE CIRCUITRY”. I upload that circuit with equation.
First stage of circuit is differential amplifier, second stage is non-inverting amplifier and last stage is use-full for limiting a voltage in range of 3.3 V.
In equation (document page no 16) why we got a “2” (first term of equation) I do not understand so please explain that thing if any confusion please refer document AN1444.
In equation Vu14 equal to input which is Iout.
Factor 2 stands for (R19+R25)/R25 which was arbitrarily assumed as fixed. Don't know why R28 and R34 haven't been also assumed as fixed in the equation, differential amplifier with G=1.
The equation is slightly inaccurate, R37 should be replaced by R37 || (R28+R35), 3.25 kOhm.