LTSpice: Failed to find DC Operating point for AC-Analysis in complex feedback circuit

Hi forum,

I have a quite complex feedback circuit which is impossible to simulate under LTSpice. The circuit's aim is a pushpull stage with current regulation. The current is sensed via U4 and U5, their output is led via current-mirrors to the transimpedance amplifier U6 which creates a voltage signal. This voltage signal is fed into the error amplifier U1 which again drives the push-pull-stage.

When I run the step analysis the LTSpice takes forever. With AC-Analysis I am not successful neither. Running the AC-Analysis I can cancel the simulation and I get the error: Failed to find DC Operating point for AC-Analysis

Do you have any idea how to get any result from the simulation?

Top Replies

    •  Analog Employees 
    Dec 30, 2020 +1 suggested

    Hi pioupus,

    I wished you had attached your circuit (*.asc file) to the post. To do so, you have to use "Insert", "image/video/file", and then click on "upload" to attach your LTspice simulation file so…