Image Number 7 for United States Patent #5745002.
A switched capacitance circuit, using a switched operational amplifier structure as an input switch of the switched capacitance, is provided with a new biasing circuit. An additional switched capacitor, switched alternately to power supply and to ground, is connected to the output side of the primary switched capacitor. Precision is retained while ensuring a rail-to-rail dynamic range, without requiring boosted control phases. Special arrangements may be implemented for controlling the amplitude of switching spikes when so required. A fully differential embodiment is also feasible with additional advantages.