Elimination of Switch On-State Resistance Effect on a Switched-Capacitor Filter Characteristic

This paper deals with the optimization of a filter (biquadratic section) employing switched-capacitor technique with respect to real features of switches, concretely their on-state resistance. At first, the conventional design of the filter with ideal switches is carried out. The filter designed in this way is then analyzed while using switches with nonzero on-state resistance. It is shown that this resistance affects the frequency response of the circuit not negligible. Therefore, component values are adjusted so that the frequency response of the filter approximates the original one with using ideal switches as much as possible. Achieving an optimal dynamic range is also taken into account. An optimization algorithm based on the differential evolution is applied for this purpose