Research On Key Technology Of High-precision Fully Integrated Laser Radar Sensor Chip

Light Detection and Ranging(Li DAR)systems have been widely used in fields of civil,military and aerospace,including Smart home,Topographic mapping,Archaeology and Spacecraft landing.The Li DAR system mainly consists of receiver and transmitter,in which the working principle and complexity of transmitter are determined by the receiver.Traditional Li DAR receiver is composed of discrete components(e.g.,photoelectric sensors,analog front-ends and data processing back-ends),which leads to the drawbacks of large volume,high cost and low long-term reliability.Therefore,the high-performance fully integrated Li DAR has already become the future development trend.The rapid development of the integrated circuits technology makes it possible for more components and complex functions integrated in a single chip.The goal of this dissertation is to design high-precision and fully integrated Li DAR chips by taking advantages of integrated circuits technology.By doing so,the power consumption,volume and cost can be lowered simultaneously.At first,we comprehensively analyze the features and operation principles of the existing Li DAR systems,and summarize the design challenges of the high-precision fully integrated Li DAR chips.Since there is no unified system-level simulation platform that can be used to simulate the Li DAR systems including different domine signals(e.g.,optical signals,analog signals and digital signals),we therefore,propose a system-level model based on MATLAB.In addition to that,a flash Li DAR capable of working in outdoor has been proposed.With a built-in background noise filtering mechanism,the significant imaging and detection performance degradations could be avoided.At last,a high-precision interpolated Time to Digital Converter(TDC)is proposed,and a Li DAR chip is designed by utilizing the proposed TDC.Li DAR is actually a complex optronic hybrid system.In different parts of this system,information exists in totally different domains.The existing optical and integrated circuits simulation software cannot support the whole system simulation.Therefore,we use MATLAB to create behavior or Mote Caro models of the optical systems,sensors,analog front-ends and post-processing back-ends.In this way,Li DAR system can be simulated and estimated in a single platform.A single point Li DAR system is designed to verify the precision of the proposed model.The measured results and simulated results are well matched.The model can be used to break down the system specs and assess the feasibility.This dissertation introduces a pulsed laser direct Time of Flight(d TOF)flash Li DAR sensor fabricated in 0.18-?m High-Voltage(HV)CMOS technology.The chip includes 32×32macro pixels and 1024 TDCs.A background noise filtering circuit with different threshold(Nth)configuration is adopted in each macro pixel(formed by four SPADs),which can suppress strong background light induced pile-up effect.To verify the imaging function and effectiveness of the noise filtering circuit,two systems are implemented(System1 for indoor imaging measurement and System2 for outdoor distance measurement).With the help of the noise filtering circuit and a reasonable signal to background noise ratio(SBR),the maximum detection range outdoors with reasonable accuracy can be greatly extended(from 12 m @Nth=1 of System2 to more than 20 m @ Nth=2 of System2 under 70 klux of background noise).The counter in the noise filtering circuit can be reused to get intensity information.A robust 13-bit TDC with a reliable reset is introduced.Thanks to a dedicated START/STOP logic and a Schmitt trigger,large TDC quantization errors can be avoided.It achieves a 200 ps resolution and exhibits an INLp-p of 3.55 LSB and a DNLp-p of 0.53 LSB.The maximum inter-frame rate can reach 270 kfps with 16 IOs operating at speed of 500 MHz.Combining9k inter-frames to get one frame,a frame rate of 30 is achieved for an indoor 3-D imaging.Examples of 2-D and 3-D imaging results are also presented.This dissertation also describes a ring oscillator-based TDC.Combined with compact local phase interpolators,a resolution of 50 ps is achieved in a 0.18?m HV-CMOS,in which low threshold voltage transistors are not available.A phase lock loop(PLL)with a replica Voltage-Controlled Ring Oscillator(VCRO)is adopted to track the process voltage temperature(PVT)variations.The resolution of TDC can be adjustable by changing the frequency division ratio.A power-saving analog buffer is used to distribute to the control voltage to all the in-pixel TDCs.Measurements show the TDC has an INLp-p of 3.85 LSB and a DNLp-p of 0.57 LSB.A flash Li DAR sensor is designed with the proposed interpolated TDC.The TDC array shows a good array uniformity,with the standard value only of 0.24 ps.A 3D imaging test has been performed to verify the TDC design and the imaging function of the Li DAR sensor.