A Low-Voltage Low-Power Fully-Integratable Automatic Gain Control for Hearing Instruments

A low-voltage low-power bipolar automatic gain control (A.G.C.) that works in the current domain and operates on a single 1.3-V battery is presented. In this A.G.C. a large time constant (50 ms) is realised on-chip. The A.G.C. consists of a gain cell, a comparator and a voltage follower. The active circuitry of the A.G.C. has been integrated in the DIMES01 process and the total circuit demonstrates operation down to 1 V with 4¿W power consumption.