A low-voltage low-power fully-integratable automatic gain control for hearing instruments

A low-voltage low-power bipolar automatic gain control (AGC) for hearing instruments that works in the current domain and operates on a single 1.3-V battery is presented. In this AGC a large time constant (50 ms) is realized on-chip. The AGC consists of a gain cell, a comparator and a voltage follower. The active circuitry of the AGC has been integrated in the DIMES01 process and the total circuit demonstrates operation down to 1 V with only 4 /spl mu/W power consumption. The compression range amounts to 38 dB. The AGC has a dynamic range (DR) of 62 dB at the output over a bandwidth of 10 kHz.>