Design Of High PSR Analog Front-End For Array Readout Circuit

Laser three-dimensional imaging technology has been widely used in terrain mapping,building virtual environments,urban modeling,military reconnaissance and other fields.The in-vehicle 3D laser imaging radar is the core component of ADAS,enabling remote ranging,auto-navigation and driverless functions.Avalanche Photodiode?APD?array detectors are key components of laser radar and are usually composed of APD arrays and corresponding readout circuits.As the application requirements increase,the array size becomes larger,and the requirements for weak signal detection capability are also higher and higher.The power consumption,area,and isolation of large-scale array systems are becoming more and more prominent.In order to cope with the use of high-performance APD,the design of array readout circuits is facing increasing challenges.This paper first introduces the principle of laser three-dimensional imaging and the basic theory of different three-dimensional imaging technology solutions,avalanche photodiodes and array readout circuits.Then the design of the array readout circuit is introduced.The problem of crosstalk between arrays is analyzed.The power supply rejection ratio enhancement circuit is designed to improve the isolation of the array readout circuit.The transimpedance amplifier with power supply rejection ratio enhancement circuit has a gain of-42 dB at low frequencies and a maximum gain of-7dB over the bandwidth,which significantly improves the power supply rejection ratio performance of the transimpedance amplifier.Subsequently,since the power supply rejection ratio performance of the capacitive feedback transimpedance amplifier is better than the resistance feedback type transimpedance amplifier at the low frequency,a capacitive feedback type transimpedance amplifier suitable for the array is designed and verified by the chip.The measured bandwidth is 89.35 MHz.In addition,for the analog front-end readout circuit system of the linear array of large photosensitive surface APD,passive feedback compensation and active feedforward compensation are introduced to introduce the zero point respectively to realize the design of high-gain,high-bandwidth transimpedance amplifier,then tape out.The simulation results show that the designed transimpedance amplifier has a transimpedance gain of 104.7d B?,a bandwidth of 198.8MHz,an equivalent input noise current of 3.65 pA/Hz^1/2,a low-frequency power supply rejection ratio of-57.8dB,and a power supply rejection ratio of less than-10.6dB over the full bandwidth..Finally,for the analog front-end readout circuit of the four-quadrant detector,the design of the high-gain preamplifier is realized by the structure of the transimpedance amplifier cascade proportional amplifier,then tape out.