基于逐元暗电流抑制的红外探测器读出电路研究

Research on Infrared Detector's Readout Circuit Based on Element-by-Element Dark Current Suppression

在航天应用领域,大部分中长波红外探测器都工作在高背景下。由于线列碲镉汞(HgCdTe)红外探测器本身的暗电流较大且各像元的暗电流具有很大的非均匀性,采用常规读出电路方案时的输出信号动态范围过小,甚至部分像元的信号电压也无法读出。采用将电压电流转换和电流存储单元相结合的方法,设计了一种具有逐元背景抑制功能的中波红外探测器线列读出电路。该方法不仅可以抑制不同像元的暗电流,而且还可以有效提高电路的信噪比,并可增大输出信号的动态范围。电路测试结果表明,在90 K低温下,电路输出摆幅为2 V,输出电压的非均匀性下降了70%,因此该研究对中长波红外探测器的工程化设计具有重要的指导意义。

Most of mid-wave and long-wave infrared detectors for space application operate against high background.For a linear HgCdTe infrared detector array,because of the large dark current of itself and the serious nonuniformity of dark current in each of its detection elements,the dynamic range of its output signal is too small and even the signal voltage of part detection elements can not be read out when the conventional readout circuit is used.A readout circuit which has an element-by-element background suppression function is designed for a linear mid-wave infrared detector array.It is designed by combining voltage-current conversion with current storage.This method not only can suppress the dark current from different detection elements,but also can effectively improve the signal-to-noise（SNR）of the circuit and increase the dynamic range of the output signal.The test result show that the circuit has its output swing of 2 V at the low temperature of 90 K and the nonuniforniity of its output voltage is reduced by 70%.Therefore,this research is of significance to the engineering design of mid-wave and long-wave infrared detectors.