A Low-Voltage Low-Power CMOS Weak Inversion Log Domain Auto Gain Control Module

This paper presents a novel scheme for low voltage low power (LVLP) log domain auto gain control (AGC) system. The AGC principle is based on proportionally biasing a CMOS weak inversion log compressor with the input signal strength. Due to the log domain processing, this AGC achieves a large dynamic range reduction (DRR) under low voltage and low power. Simulated results at 1-V supply voltage for 0.18-mum CMOS process validate the principle. The total quiescent drain current of the AGC core is 0.3 muA. The AGC bandwidth is 1 KHz. It is suitable for LVLP bio-medical application such as electrocardiogram (ECG) signal adapting.