Inductor DCR current sensing

Discussion in 'The Projects Forum' started by Engico, Mar 8, 2013.

  1. Engico

    Thread Starter New Member

    Mar 8, 2013
    I have made a simple buck converter in orcad pspice. Its a 12V/1.2V 12A buck
    It has been designed with ideal considerations. I want to sense the inductor current, so i have employed the inductor DCR current sensing scheme with a RC network in parallel to the matching the time constants L/R and RC the voltage drop across the inductor DCR is same as the capacitor voltage drop.
    so to sense this current i connected a current sense amplifier MAX4372F with a 50V gain.
    The problems that i face are
    1) when i try to tap the voltage across the capacitor it does not maintain the same drop as the DCR
    2) Also the MAX4372F does not give a constant output for different values of output resistance, it keeps on changing for different resistors