Design Of ROIC With Dual Mode Infrared Focal Plane

Infrared photoelectric detection imaging technology has gradually become one of the core technologies in military,medical,industrial,security and other fields,and is constantly developing in the direction of a wider range of applicable scenarios,more diverse detection modes,and lower costs.Infrared Focal Plane Array(IRFPA),as the core component of infrared photoelectric detection imaging system,is composed of detector and read-out integrated circuit(ROIC),which is the key to detect,identify and analyze infrared information of objects.Among them,ROIC,as the front-end signal processing circuit of IRFPA,determines the function and performance of the entire infrared imaging system,and is currently a hot spot for research at home and abroad.Aiming at the problem of single detection function of traditional IRFPA,this paper designs a dual-mode infrared focal plane ROIC for HgCdTe avalanche photodiode(APD)working in a linear state,which is equipped with traditional 2D planar imaging The passive detection mode can also be applied to the target based on the photon time of flight(TOF)detection of active detection mode to achieve 3D depth of field information imaging including distance information.The pixel circuit is composed of a new type Capacitive Feedback Transimpedance Amplifier(CTIA),which contains two feedback capacitors.The access mode of the capacitor is switched according to the operating mode to realize the processing of the weak photo-generated current signal.It is converted into a voltage value containing intensity information and distance information.At the same time,this paper analyzes the working mode of the dual-mode readout circuit,and proposes a readout that combines two methods of Integrate Then Readout(ITR)and Integrate While Readout(IWR)Compared with the traditional readout method that only uses ITR,it can greatly save the readout time and effectively improve the work efficiency of the system.Based on the TSMC 0.18?m CMOS process,the dual-mode infrared focal plane ROIC circuit and layout of the array size of 16x16 and the pixel area of 50x50 ?m2 were completed on the Cadence Electronics Design Automation(EDA)development platform.Design,pre-simulation and post-simulation verification,participate in MPW tape-out and complete the packaging test of the developed samples.The ambient temperature of the circuit is-196?.At 5V supply voltage,the simulation results of the circuit show that the full well capacity can reach 8.4Me-.At the readout clock frequency of 4MHz,the frame rate is 12kfps,and the passive detection mode The linearity is greater than 99%,the detection distance of the active detection mode is about 900m,and the absolute value of the relative error rate is less than 1%.Due to the limited test conditions,this article completed part of the performance test of the single-pixel circuit under normal temperature and ultra-low temperature environment.The test results show that the linearity of the circuit is 88.38%at room temperature,which is 10.4%lower than the room temperature simulation results;the full well capacity is-8.4Me-at-196?,compared with the room temperature test results,the slope of the integration curve is obvious More stable,linearity is better than normal temperature results.