The Key Technological Research For Receiving Chip Of Pulsed TOF Mobile LIDAR

For unmanned driving system,how to use all kinds of sensors to detect obstacles dynamically on the roadway,such as cars,bicycles and pedestrians,is one of the core problems need to be solved.LIDAR can obtain obstacle location information directly,because they have high measurement precision and have the rejection of background light.Therefore,LIDAR has the prospect to become one of the most important unmanned-vehicle sensors.A complete pulsed TOF receiving chip includes pixel arrays and post-stage related IC controlling and processing units.Pixel arrays are composed of single-photon avalanche diode(SPAD)arrays and quenching circuits.Post-stage related IC controlling and processing units are made up of Time-to-Digital converters(TDC),time-correlated single-photon counting(TCSPC)modules and so on.For this kind of chips,there are two key technologies which are the device structure and circuit structure.The circuit structure includes the quenching circuits and post-stage related IC controlling and processing units.This paper focus on designing circuit structure of pulsed TOF mobile LIDAR receiving chip based on SMIC 0.13μm CIS(CMOS Image Sensor)technology,including controllable active quenching circuits,multiple-pixel sharing TDC circuit,Time-to-Digital converters(TDC)and single-photon counting histogram circuit.In addition,a proposed simulation platform has been used to verify the functional correctness of circuit structure.The main innovation points of this paper are as follows:1.Controllable active quenching circuits are proposed to accelerate quenching device avalanche,reduce afterpulsings effectively and control the SPAD whether in Geiger mode or not.2.In the case of adopting TCSPC technology,we improve the fill factor of photosensitive parts effectively by sharing a TDC to multiple SPAD to improve the imaging performance of the chip.Additionally,the impact of sharing ratio and measurement range to frame rate has been analyzed.3.In order to verify the functional correctness of circuit structure of the chip,a simulation platform has been proposed.This simulation platform is composed of SPAD equivalent models and avoid mature technology limitations in the process of chip developing to ensure the smooth completion of the project.Because device designing need long time of technological debugging,the significance for this paper is that the functional correctness of circuit structure can be verified before the SPAD device completed.When SPADs are designed successfully,we can speed up the development of a complete pulsed TOF mobile LIDAR receiving chip and shorten design cycle.This can lay a solid foundation for processing industrialization and LIDAR prototype manufacturing.