A compact CMOS Class-AB analog median filter

A power efficient implementation of a CMOS Class-AB analog median filter is presented. The median detector is based on transconductance comparators accomplished with new Differential Flipped Voltage Followers. The followers employ a current comparator to switch-on an auxiliary transistor to drive additional current whenever it is required, performing Class-AB operation. Area is saved by taking advantage of the large impedance node of the current comparator to accomplish Miller frequency compensation. Simulation results using the ON-SEMI 0.5μm technology parameters validate the proposed structure.