A 18.9-nA standby current comparator with adaptive bias current generator

An ultra-low power comparator circuit using adaptive bias current generator (ABCG) is proposed. The circuit consists of an input differential pair, an ABCG, and a latch circuit. The ABCG generates an adaptive bias current, and the latch circuit determines the output logic and controls the operation of the ABCG for ultra-low power dissipation. The ABCG and the latch operate only when the input voltage levels and the logic of the latch do not correspond with each other. Measurements demonstrated that the circuit can achieve highspeed and low-power dissipation due to such operation. The standby current was 18.9 nA with a 10-nA bias current. The power dissipation was 88.5 nW at a 1-kHz input frequency and 3-V supply voltage.