CCD图像传感器输出节点电荷容量设计

Design for Charge Handling Capacity of Sense Node in CCDs

摘要:

本文从CCD的满阱电荷容量和片上放大器的工作电压范围两个方面对器件的节点电荷容量进行了设计,并推导出了输出节点电荷容量设计的优化公式。从公式中可以看出,输出节点的电荷容量设计除了需要满足CCD信号电荷转移本身所需的容量值以外,还必须保证节点处的电压变化范围在输出放大器线性工作区域内,才能使信号电荷能够完整线性地被放大器输出,从而保证CCD器件整体的非线性和满阱容量性能。因此,输出节点电荷容量的设计除了需要考虑节点自身的电容外,还应综合考虑输出放大器相关MOS管的宽长比、阈值电压、工作电压等因素。

Abstract:

In this paper, the handling capacity of sense node was designed based on CCD’s full well charge capacity and the work voltage range of the on chip amplifier, and the expressions for the optimizing design of the handling capacity of sense node was deduced. As can be seen from the expressions, besides matching the transferring of the full well charge for the CCD, the voltage change range of sense node inducted by the signal charge also must be in the linear region of the on chip amplifier so that the CCD’s output nonlinearity and full well charge capacity will not be affected. Therefore, the CCD designers must consider not only the sense node’s capacitance, but also the MOSFET’s wide-length ratio, threshold voltage, work voltage etc. of the on chip amplifier during the design of charge handling capacity of sense node.