Behavioral-level envelope-following using Broyden´s method

This paper presents a modified envelope-following method for the simulation of clocked analog circuits such as power converter circuits. The envelope of the high-frequency clock can be traced by computing the circuit response over a subset of cycles, thereby reducing the simulation time. The conventional solution process for envelope-following requires that a nonlinear boundary equation be solved at every iteration. The approach followed in this paper is to use the Quasi-Newton technique called Broyden´s technique to solve this equation. This allows the envelope-following technique to be applicable to circuit descriptions which contain arbitrary behavioral models. In addition, it can be wrapped around any time domain simulator without altering the internals of the simulator. This results in a powerful general-purpose technique for envelope tracing of the solution waveforms for periodic circuits