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文中提出了一种基于行列控制字的新开窗架构,并提供了一种电路实现方式。表1对比了各个架构。
Reference Ref.[15] Ref.[14] Ref.[13] This paper Architecture Gray code addressing Subarray control word Single pixel
control wordRow and column control word Min. size of ROI 4×4 32×32 1×1 1×1 Increase the number of transistors per pixel 0 0.26 34 - Control word writing time 0 32·Trclk 1 024·Trclk (1-1 024)·Trclk Existing the race and hazard phenomenon Yes No No No Different array sizes circuits need to be custom redesigned Yes No No No Table 1. Comparison of different schemes
格雷码译码器架构理论最小窗口可以达到1×1,目前美国indigo公司产品ISC0403最小尺寸为4×4,该架构采用异步读出模式,存在竞争冒险的风险,而且不同面阵大小电路需要重新定制化设计。
采用同步读出模式的子阵列架构与单像元控制字架构不会产生竞争冒险现象,但是在像元内增加了晶体管,导致像元尺寸难以缩小。
文中提出的架构采用同步读出模式,避免了竞争冒险现象,同时该架构采用了重复模块,在面阵大小变化时不需要重新设计,可扩展性相对较好;相对于子阵列架构来说,该方案的最小窗口尺寸达到1×1,而且将控制电路设计于面阵外围,没有占用像元面积,使得像元尺寸容易缩小;相对于单像元控制字方案,在同样的最小窗口尺寸下,没有占用像元面积,而且大大提高了窗口切换速度。
Research on ROI readout technology of ROIC
doi: 10.3788/IRLA20220100
- Received Date: 2022-03-25
- Rev Recd Date: 2022-04-20
- Publish Date: 2022-11-30
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Key words:
- infrared FPA /
- readout integrated circuit /
- region of interest(ROI)
Abstract: Region of interest (ROI) readout is an important technology used in the infrared focal plane array(IRFPA) and image sensor readout integrated circuits to improve the frame rate and reduce the bandwidth, which is realized by the reduced ROI size and the readout data volume. Two ROI readout modes including asynchronous readout and synchronous readout are introduced in this paper. The asynchronous readout mode exhibits poor scalability and the problem of the competitive risk, while the synchronous readout mode occupies pixel area and the ROI switching speed is slow. To solve these problems, this paper proposes a row-column control word architecture based on synchronous readout mode, and a reusable unit circuit is designed to improve the scalability for various array size. The circuits and layout for the proposed architecture are designed, which are verified by circuit simulation. Compared with other architectures, the proposal realizes ROI readout at arbitrary position with minimum size of 1×1. Moreover, problems including the occupying of pixel area and competitive risk are solved, as well as the ROI switching speed.