Design Of Microchannel Plate Charge Cloud Detection Integrated Circuit

Since the 1960 s,with the cooperation of the global industrial chain,integrated circuit engineering has been developed.Microchannel plate is an optoelectronic device with the advantages of low dark current and high temporal and spatial resolution,which can be used to detect weak optical signals.The microchannel plate can amplify the detected weak light signal into a charge cloud.Such signals can be processed by integrated circuits to obtain corresponding time information.So far,there has not been an ASIC integrated with the microchannel plate and universal chips will lead to higher power consumption and lower precision.The circuit scheme has become the focus of current research.The main content of this paper is to design a charge signal detection circuit for single-photon time-of-flight detection suitable for microchannel plate,including the introduction of microchannel plate photodetector,the design of analog front-end circuit,the design of time-to-digital converter and the analysis of its systematical error,the design of the analog optical pulse circuit,the analysis of the overall dead time and the design of the layout.This paper introduces the combination of the microchannel plate and the chip,discusses types of time detection circuits,such as leading edge trigger timing,constant fraction discrimination,double threshold trigger timing.The paper selects a suitable time detection circuit.A suitable transimpedance amplifier is selected for the compromise and optimization between bandwidth,gain and noise.A low-latency comparator is designed with high voltage swing and low latency.At the same time,this paper proposes a combined high-precision time-to-digital converter.The paper analyzes the system error of the time-to-digital converter in detail and gives the corresponding solution.Finally,the influencing factors of the overall dead time are analyzed.This paper adopts SMIC 0.18?m Bi CMOS process to design,including transimpedance amplifier,low delay comparator,time-to-digital converter.To assess the circuit,the single pixel circuit also integrates an analog light pulse circuit in PWM mode.The area of a single pixel is500?m?200?m(including pads),and the time-to-digital converter(TDC)can achieve photon timeof-flight measurement with a resolution of 50 ps under a high-frequency clock of 640 MHz.By measuring the arrival time of the charge cloud and the size of the charge,the circuit can calculate the photon flight time and the number of photons incident on the microchannel plate to realize light detection.