5. Switched-Capacitor Circuits

The elusive goal of the lossless charge transfer from one circuit node to another has been the main focus of analog sampled-data processing starting from the bucket brigade and CCD to switched-capacitor circuits. Opamp with capacitive feedback is the most accurate analog component that can sample and amplify signal with highest accuracy. Their voltage transfer accuracy is solely dependent upon the DC gain and nonlinearity of the opamp. The lossless voltage transfer regardless of the opamp gain and nonlinearity error is achievable by eliminating it right from its source in the analog domain. When applied to the pipelined ADC, the linearity performance can be enhanced by adaptively cancelling them based on the global zero-forcing LMS feedback. Two featured circuit concepts can be incorporated to implement error-free switched-capacitor amplifiers. An all-analog feedback self-trimming mechanism is shown to solve the classic opamp gain and nonlinearity problem by employing a single-parameter adaptation scheme.