Switched-mode AGC circuits with internally created reset module for burst-mode unbalanced data optical receiver

This paper presents an innovative switched-mode auto gain control (AGC) circuit with internally created reset module for DC-10Mb/s burst-mode unbalanced (BMU) optical data transmission.Conventional AGC circuit is inappropriate for BMU data transmission because it is based on average level detection and requires considerable time to settle on a predefined gain.Therefore,we adopt a fast switched-mode AGC based on peak level detection.After the gain is adjusted,the peak level detectors need to re-detect the peak level of the input signal.Thus,we develop an internally created reset module.This AGC with reset module exhibits a fast operation and achieves an adjusted stable gain within one-bit,avoiding any bit loss up to 10Mb/s data rate.During power-up,the peak level detectors possibly hold an uncertain level resulting in the bit-errors.We propose a power-up reset circuit to solve this problem.Designed in a 0.5 μm CMOS technology,the circuit achieves an optical sensitivity of better than - 30dBm and a wide dynamic range of over 30dB with a power dissipation of only 30 mW from a 5V supply.