320×256中/长波双色IRFPAs读出电路设计

中波与长波探测器的光电流及动态输出阻抗存在数量级的差别。为满足积分时间及读出信号信噪比的要求,采用像元间多电容共享的方案,设计了一种高集成度的320256双色红外焦平面读出电路。该电路选用直接注入(DI)结构作为中波输入级,而长波输入级则选用了缓冲注入(BDI)结构。其缓冲放大器采用单边结构,具有高增益、低功耗、低噪声的特点,降低了输入阻抗,提高了注入效率。基于HHNEC 0.35 m 2P4M标准CMOS工艺,完成了芯片的设计与制造。经测试,引入电容共享方案后其有效电荷容量达到70 Me-/像元,电路各项功能正常,在光照条件下,芯片呈现出高的灵敏性。在2.5 MHz读出速率下,中波及长波输出电压范围均大于2 V,非线性小于1%。在100 f/s帧频下,整体功耗小于170 mW。

320×256 MW/ LW dual-color IRFPAs readout circuits

The photocurrent and dynamic output impedance of MW detectors differentiate from LW by several orders of magnitude. For the requirement in integrating time and readout SNR, a designing scheme of a highly integrated readout circuit for 320256 dual-color infrared focal plane arrays(IRFPAs) was proposed by adopting a sharing methods between pixel capacitors. In this circuit, the DI structure was chosen as the MW injection stage and the BDI structure was used for LW. The buffered amplifier had a unilateral structure which always performanced with high gain, low consumption and low noise, thus it reduced the input impedance and improved the injection efficiency. The chip was designed and manufactured based on HHNEC 0.35 m 2P4M standard CMOS process. In the testing process, this chip presented a normal operating state and was sensitive enough to the change of illumination. The total effective charge capacity reached 70 Me-/pixel. Under 2.5 MHz output speed, the output swings of MW and LW were larger than 2 V and the nonlinearity less than 1%. The total power consumption was less than 170 mW when working with the frame rate of 100 f/s.