A Novel Balanced Detection Based Optoelectronic Front End Circuit for FMCW Lidar System (Sensor System Best Paper)

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First Author:W. Zhu

Correspondence Author:, and C. Wang*

Co-author:, W. Yuan, D. Wu, Y. Zhao, Z. Lu, G. Yu, Y. Yu

Journal:2024 IEEE International Symposium on Circuits and Systems (ISCAS 2024)

Included Journals:EI

Discipline:Engineering

First-Level Discipline:Electronic Science And Technology

Document Type:C

Abstract:To take the advantages of the remote detection distance and wide detection range from Frequency Modulated Continuous Wave (FMCW) LiDAR system, this paper proposes a novel optoelectronic front end circuit consisting of a balanced-detection (BD) based interface and an Analog Front-End (AFE) circuit. The BD based interface adopts a coupler and differential photodiodes to reduce parasitics and noise, which extends the bandwidth and dynamic range of AFE circuit. The AFE circuit employs a three-stage fully differential shunt-feedback pre-transimpedance amplifier to reduce input impedance and a two-stage variable gain post-amplifier to enhance gain regulation range, which further improve the bandwidth and dynamic range. The proposed AFE circuit in a 40-nm CMOS has achieved a gain of 100 dBΩ from 1 MHz to 132 MHz and a dynamic range up to 66.2 dB. The input-referred noise current is 5.8 pA/√Hz and the power consumption is 11.64 mW at 1.1 V. Compared with the state-of-art designs, the proposed AFE circuit has achieved 1.2× bandwidth expansion and a considerably-improved dynamic range.