A new CMOS readout circuit design for the IR FPA with adaptive gain control and current-mode background suppression

A new CMOS current readout structure for the infrared (IR) focal-plane-array (FPA), called the buffered gate modulation input (BGMI) circuit is proposed and analyzed. The new readout circuit can achieve a high charge sensitivity with the adaptive current gain and has a good immunity from threshold-voltage variations. Moreover, the readout dynamic range is dramatically increased by using a threshold-voltage independent current-mode background suppression technique. The BGMI circuit with current-mode background suppression has been designed and simulated it has been shown that high injection efficiency, high charge sensitivity, high dynamic range, large storage capacity, and low noise performance are achieved in a 50×50 um² pixel size. These advantageous traits make the BGMI circuit suitable for the applications with a large background current range