AWEswit: A switched capacitor circuit simulator

Abstract

This paper presents a switched capacitor circuit simulator, AWEswit. AWEswit exploits the cyclical reconfiguration of switched capacitor circuits through a sequence of continuous-time circuits. It employs Asymptotic Waveform Evaluation (AWE) to estimate the response of the state variables (capacitor voltages) in each switching phase. For accuracy, a horizontal Pad6 sequence is employed to extract dominant pole models for the response of the state variables. In addition a general technique to handle complications in the AWE analysis resulting from loops of voltage sources and capacitors is presented. This technique makes AWEswit compatible with that class of switched capacitor simulators which operate in the charge-voltage regime.

Behavioral modeling of switched-capacitor sigma-delta modulators

“…The limited dc gain of the integrator increases the in-band noise. The transfer function of the integrator with leakage becomes (6) The dc gain of the integrator , therefore, becomes…”

“…They can be general-purpose like SWITCAP (or its evolution AWEswit [6]) or especially devoted to oversampled modulators like MIDAS. They achieve an excellent speed of simulation, but the nonidealities modeling capabilities are poor.…”