带衬底温度补偿的微测辐射热计读出电路

Readout Circuit with Substrate Temperature Compensation for Uncooled Microbolometer

非致冷微测辐射热计具有较大不均匀性,并且输出响应受衬底温度影响很大.提出的读出电路在读出信号的同时能够扩大探测阵列的允许衬底温度.电路采用多列像素共享容式跨阻放大器(CTIA)和DAC,用补偿暗像元扣除静态电流,校正数据经DAC转换送至MOS管的栅极以控制偏置电流达到温度补偿目的.该电路灵敏度高、动态范围大,对于128×128面阵可以达到30Hz以上的帧频,通过PSPICE仿真验证了该读出电路的可行性.

The output responsivity of uncooled microbolometer is nonuniform, and greatly influenced by the substrate temperature. The proposed circuit can relax the restriction on the substrate temperature while reading out the image signal. It includes column-shared CTIA, DAC, and dummy pixel for static current reduction. Correction data are transferred by DAC to the gates of MOS transistors, to control the bias voltage. This circuit has higher sensitivity, wider dynamic range, and frame frequency of more than 30 Hz for 128 × 128 array. PSPICE simulation results show that this circuit could function well.