Switched capacitor circuit synthesis using voltage inversion principles

The synthesis of switched capacitor circuits of a wide variety of types is presented. First and second order sections for cascade and multifeedback filter realisations, integrators for functional simulation of classical LCR filters and simulated impedances for topological element simulation of LCR filters are considered. A principle of voltage inversion is shown to be a common aspect for all these types of circuit realisation. After considering techniques for the realisation of such voltage inversion, the principle is applied to a number of required subcircuits and hence to a number of diverse filter examples. In general, the circuits developed, which have a generic similarity, have a number of attractive features including the possibility of realising bilinear transformed transfer functions, minimisation of the number of amplifiers required and ability to apply scaling for optimum dynamic range and capacitor area minimisation. One of the results of this approach based on voltage inversion is a single amplifier, bilinear bandpass biquad