Post by blue111 on Sep 2nd, 2017, 12:22am
Hi, I am stuck at one analog circuit problem. So far my friends could not solve it.
This is a gyrator made up of two gm-cells (X1 and Gm2 blocks), transforming CL into active inductor.
equivalent inductance value, Leq = CL / [(gm of X1 circuit block)*(gm of Gm2 circuit block)]
1) Should I simulate the value of overall transconductance of Gm2 circuit block independently or inside the larger circuit with the presence of Cs and CL ?
2) Why would V(IN) = Vb ? is it because of https://www.quora.com/Why-does-an-op-amp-show-virtual-short-during-negative-feedback-and-not-positive-feedback ?
Note: V(IN) is the gate voltage node of mosfet M6 in Gm2.sch
and X1 is just a CMOS inverter
Note: The complete gschem schematics and ngspice simulation plots could be obtained from https://github.com/promach/frequency_trap