A generalized high-precision analog CMOS rank finder for max/min/med application

Minimum and maximum circuits are basic fuzzy logic gates. Median filter is usually adopted in image noise cancellation. All of them are the special situation in a ranker finder. In this paper, a high-precision rank finder with configurable capability for maximum/minimum/median application is designed. Without modifying the circuit, this design can find the arbitrary rank among a set of input variables by setting select-signals. Moreover, the circuit schematic is regular and modular. The input dynamic range is rail-to-rail, so it can be used in fuzzy logic circuit design. This circuit has been simulated using 0.5 /spl mu/m CMOS technology by HSPICE. The results show that operating speed of the circuit is 250 ns, and the resolution is 3 mV for 3.3 V supply voltage.