Programmable CMOS current comparator circuit for analogue VLSI neural networks utilizing identical small-dimension MOS transistors†

Abstract

A programmable CMOS current comparator circuit is presented which employs seven identical small-dimension MOS transistors, and whose threshold current is adjustable without the need to change any of the MOS transistors. Using transistors with W/L of 2/0.6 um and a 5 V supply voltage, the comparator can be programmed to detect currents over the range from 50 nA to 550 μA. With W/L of 3/0.6 μm and a 3.3 V supply voltage, the programmable range is from 20 nA to 365 μA. Simulations for these configurations indicate that the circuit has propagation delays of 4.125 ns and 4-08 ns, respectively.