新型电流镜积分红外量子阱探测器读出电路的设计分析

设计了一种偏压可调电流镜积分(Current Mirroring Integration,CMI)红外量子阱探测器焦平面CMOS读出电路。该电路适应根据偏压调节响应波段的量子阱探测器,其中探测器偏压从0.61 V到1.55V范围内可调。由于CMI的电流反馈结构,使得输入阻抗接近0,注入效率达0.99;且积分电容可放在单元电路外,从而可以在一定的单元面积下,增大积分电容,提高了电荷处理能力和动态范围;为提高读出电路的性能,电路加入撇除(Skimming)方式的暗电流抑制电路。采用特许半导体(Chartered)0.35 m标准CMOS工艺对所设计的电路(16×1阵列)进行流片,测试结果表明:在电源电压为3.3V,积分电容为1.25pF时,电荷处理能力达到1.3×107个电子;输出摆幅达到1.76V;功耗为25mW;动态范围为75dB;测试结果显示CMI可应用于高性能FPA。

Design of A Novel Current Mirroring Integration Readout Integrated Circuit for Quantum Well Infrared Photodetectors

An kind of adjustable bias voltage CMI (Current Mirroring Integration) CMOS readout circuit was designed for Quantum Well Infrared Photodetectors(QWIPs) FPA which response different spectrum by adjusting QWIP bias voltage. The bias voltage can be adjusted from 0.61V to 1.55 V. With the current feedback in the CMI structure, very low (ideally zero) input impedance and high (0.99) injection efficiency were achieved. Integration capacitor can be placed outside of the unit pixel, reducing the pixel area and allowing to integrate the current on larger capacitances for larger charge storage capacity and dynamic range. To achieve high readout performance, the circuit introduce the dark current skimming structure. An experimental ROIC chip of a 16×1 array has been fabricated in Chartered 0.35μm CMOS process, test result showed that the ROIC provides a maximum charge storage capacity of 1.3×107e-for a 1.25 pF integration capacitance and 3.3 V power supply, output voltage swing is 1.76 V, power consumption is 25mW, dynamic range is 75dB.The experimental results showed that the CMI circuit can be used for high performance FPA.