基于分布式∑/△与扩展量化的红外焦平面阵列像素级/列级混合式模数转换方法研究

项目名称： 基于分布式∑/△与扩展量化的红外焦平面阵列像素级/列级混合式模数转换方法研究

项目编号： No.61475009

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 鲁文高

作者单位： 北京大学

项目金额： 90万元

中文摘要： 甚小尺寸像素的电荷存储能力限制了红外成像的信噪比，像素级(/(调制利用过采样提升等效电荷存储能力，但无源型线性度差，有源型则占据较大像素面积。本申请提出像素级/列级分布式电荷增量型(/(调制技术，像素级实现光电流积分、余量电荷存储，列级实现电荷比较、电荷转移，像素内等效电荷存储能力增大，信噪比提高。拟研究基于低阻化节点的混合式逐次逼近模数转换方法，提出共享输出级电流的低阻化方法，降低了功耗，并分时复用高精度调制器校正各节点电压，提高了线性度。拟提出基于列间相关性的数据存储、数字处理方法，并具有防溢出功能，进一步减小像素数据存储量，释放了面积。 拟通过MPW验证所提创新，根据测试完善模型。拟完成演示样品流片与测试：工艺0.18(，阵列384×288，像素10(17(，15-bit A/D，信噪比(80dB，功耗(100mW。为甚小尺寸像素红外焦平面阵列模数转换提供更充分的科学依据和技术准备。

中文关键词： 红外焦平面阵列；模数转换；像素级/列级混合式；信噪比；∑/△调制

英文摘要： In infrared imaging, SNR is limited by charge storage ability of pixel with very small size. The pixel-level Σ/Δ modulator uses oversampling to improve charge storage ability. But passive modulator shows bad linearity while active modulator occupies large area in pixel. In this application, a pixel-level/column-level distributed charge incremental Σ/Δ modulation is presented: Integration of photocurrent and residual charge storage are achieved in pixel-level, while charge comparison and charge transfer are achieved in column-level. As a result, pixel's equivalent charge storage ability is increased and SNR is enhanced. Technique of hybrid SAR A/D conversion with low-resistance nodes is studied in this application. Implementation of low-resistance by sharing current is proposed to decrease power dissipation. And a high precision modulator using time-sharing multiplexer is adopted to calibrate voltage of each node so that the linearity can be increased. Correlation of quantitative data among columns is studied in this application. And method of data storage and digital processing based on correlation is proposed. This method can prevent overflow and lower the requirement of data storage to save area. The innovations will be verified through MPW and model will be ameliorated according to experiment results. Tape-out and test of demo ASIC will be accomplished using 0.18μm process. The array size is 384×288, the pixel size is 10～17μm and the precision of A/D convertor is 15 bit. The expected SNR is over 80dB and the expected power is less than 100mW. This research provides sufficient scientific basis and technical preparation for A/D conversion in Infrared FPA with very small-sized pixel.

英文关键词： Infrared FPA;A/D Conversion;Pixel-level/Column-level hybrid;SNR;∑/△ Modulation