New high frequency current-mode precision rectifiers

The supply-current sensing technique is a useful method for obtaining a current output from an op-amp. This technique has been exploited successfully by Toumazou and Lidgey in several applications, most notably for development of a first generation of current-mode instrumentation amplifiers and current-mode precision rectifiers. The frequency responses of these current-mode precision rectifiers were demonstrated to be significantly better than classical designs. The new precision rectifiers described here are a further evolution of these earlier supply-current sensing current-mode designs. The performance has been extended by using (i) an alternative supply-current sensing strategy, (ii) the use of current-followers and (iii) maximally symmetrical topologies