Improving DC convergence in a circuit simulator using a homotopy method

To help resolve DC convergence difficulties in a circuit simulator, the authors constructed a homotopy suitable for solving equations describing transistor circuits. The authors describe its implementation in the ADVICE circuit simulator using a software package that implements a globally convergent homotopy algorithm. Homotopy methods proved robust, accurate, and capable of finding multiple operating points. The authors give simulation examples of various bipolar and MOS transistor circuits that could not be simulated using existing techniques, while the solution was successfully obtained using homotopy methods.