High frequency performance of current-mode precision full wave rectifiers

The current-mode topology reported by Hayatleh et al. [1993] provides an improved high frequency performance over the traditional design, but the circuit response still begins to degrade significantly at-about GB/100, where GB is the gain-bandwidth of the op-amps being used. Detailed investigation of the principal degradation mechanisms has been undertaken and from the results of this study two main causes for the non-ideal performance have been identified. Even though the work reported here is specifically related to the PFWR, these two-mechanisms responsible for degrading the performance at high frequencies also apply in part to all PFWR and a wide number of circuits that employ opamp/diode feedback structures