具有记忆功能背景抑制结构的共享型读出电路

甚长波红外(VLWIR)波段富含大气湿度、CO2含量及云层结构和温度轮廓等大量信息,是大气遥感的重要组成部分。为了满足现阶段甚长波红外探测器对读出电路高注入效率、大动态范围、稳定的探测器偏压、长积分时间等需求,设计了一种具有记忆功能背景抑制结构的共享型读出电路。该电路采用22四个相邻的探测器像元共用一个读出电路单元的共享缓冲直接注入级(SBDI)结构,增大了单元电路的面积,在单元内实现了具有记忆功能背景抑制结构的设计,其总积分电容达到8.8 pF,有效延长了积分时间和红外焦平面的信噪比(SNR),并改善了动态范围和对比度。基于HHNEC CZ6H 0.35 m 1P4M标准CMOS工艺,完成了电路的流片制造。仿真及测试结果表明:在50 K温度下电路功能正常,其动态范围大于90 dB,线性度优于99.9%,积分时间可达74 s,达到了设计要求。该读出电路适用于甚长波红外探测器。

Shared readout integrated circuit with memory-function background suppression

Very long wave infrared(VLWIR) band widely used in remote atmosphere sounding applications is particularly rich in information about humidity, CO2 levels and provides additional information about cloud structure and the temperature distribution. In order to meet the requirements of VLWIR detectors at present stage, a shared readout integrated circuit with memory-function background suppression was designed for its high injection efficiency, large dynamic range, stable detector bias, long integration time and some other advantages. In this design, the share buffered direct injection(SBDI) input circuit was used to minimize pixel area limitation and to maximize the efficiency of memory-function background suppression by 22 four neighboring pixels united. The total integration capacitor could reach up to 8.8 pF that has larger capacity, extended integration time, and increased the signal-to-noise ratio (SNR) of infrared focal plane array(IRFPA). At the same time, better contrast and dynamic range were also achieved. The final chip was fabricated with HHNEC CZ6H 0.35 m 1P4M process technology. The simulation and test results show that the dynamic range is over 90 dB, the linearity is more than 99.9%, the integration time could be extended to 74 s when the ROIC operates at the temperature of 50 K.