Spice Model for Computer-Aided Design of Biopotential Amplifier

Abstract

There are many different kinds of biopotential signal. These signals are tiny in amplitude and the measurement is easily corrupted by external interference. For these reasons, the design of high-quality biopotential amplifier is usually an empirical task. To make the design of biopotential amplifier more efficient, this study proposes a simulation model for bioelectric signal measurement such that the design task can be achieved thoroughly by powerful computer-aided design (CAD) tool. The proposed model has two distinct features, one is the simulated biopotential signal is used for the genesis of biosignal, and the other one is the skin-electrode impedance is replaced by its corresponding equivalent circuit, which is a complex RC network. To verify the feasibility of the proposed model, an ECG amplifier is designed in Spice-related CAD tool and is implemented for ECG recording. From the results, the amplifier characteristics agree well between the simulated and the implemented circuit. Besides, the effect due to the commonly encountered power-line interference during biopotential measurement can be reasonably evaluated in the proposed model.