ICube Research Institute, University of Strasbourg, 23 Rue du Loess, CEDEX, 67037 Strasbourg, France.
Electronics Laboratory, Faculty of Engineering, University of Guilan, Khalij Fars Highway, Rasht 4199613776, Iran.
Sensors (Basel). 2021 Jun 8;21(12):3949. doi: 10.3390/s21123949.
The usage of single-photon avalanche diode arrays is becoming increasingly common in various domains such as medical imaging, automotive vision systems, and optical communications. Nowadays, thanks to the development of microelectronics technologies, the SPAD arrays designed for these applications has been drastically well-facilitated, allowing for the manufacturing of large matrices. However, there are growing challenges for the design of readout circuits with the needs of reducing their energy consumption (linked to the usage cost) and data rate. Indeed, the design of the readout circuit for the SPAD array is generally based on synchronous logic; the latter requires synchronization that may increase the dead time of the SPADs and clock trees management that are known to increase power consumption. With these limitations, the long-neglected asynchronous (clockless) logic proved to be a better alternative because of its ability to operate without a clock. In this paper, we presented the design of a 16-to-1 fixed-priority tree arbiter readout circuit for a SPAD array based on asynchronous logic principles. The design of this circuit was explained in detail and supported by simulation results. The manufactured chip was tested, and the experimental results showed that it is possible to record up to 333 million events per second; no reading errors were detected during the data extraction test.
单光子雪崩二极管阵列的使用在医学成像、汽车视觉系统和光通信等各个领域变得越来越普遍。如今，得益于微电子技术的发展，为这些应用设计的 SPAD 阵列得到了极大的促进，可以制造出大型矩阵。然而，随着降低能耗（与使用成本相关）和数据速率的需求，对于读出电路的设计提出了越来越多的挑战。事实上，SPAD 阵列的读出电路设计通常基于同步逻辑；后者需要同步，这可能会增加 SPAD 的死区时间，并且时钟树管理会增加功耗，这是众所周知的。有了这些限制，长期被忽视的异步（无时钟）逻辑被证明是一个更好的选择，因为它能够在没有时钟的情况下运行。在本文中，我们提出了一种基于异步逻辑原理的用于 SPAD 阵列的 16 到 1 固定优先级树仲裁器读出电路的设计。详细解释了该电路的设计，并提供了仿真结果的支持。制造的芯片进行了测试，实验结果表明，它每秒可以记录多达 3.33 亿个事件；在数据提取测试中没有检测到读取错误。
