A CMOS readout integrated circuit with automatic deselecting function for IRFPA

Abstract

In this paper, a readout integrated circuit (ROIC) is presented for improving the operability of the LWIR arrays by using a super-pixel detector format scheme, identifying and deselecting the bad elements automatically. This ROIC features an input stage based on buffered direct injection (BDI) structure, which uses a differential stage to provide the inverting gain to improve linearity and to provide tight control of the detector bias. The threshold voltage of bad element de-selection is adjustable and the circuit could de-select the bad element automatically. The simulation result show that the bad sub-element de-selection precision is up to nearly 0.2nA when the threshold current is about 590.8nA. We analyze the errors affecting the precision and the calculated precision is 2nA. Finally, we discuss the bad sub-element de-selection precision in different integrating time.