A 4-GS/s current-domain analog front end (CurAFE) for phase-coded pulse-compression direct time-of-flight (dTOF) automotive Lidar has been realized in 130-nm CMOS. The permissible eye-safe laser energy is transmitted in the form of a burst of optical sub-pulses. The burst embeds a phase coding designed to have an auto-correlation function with a maximum peak-to-sidelobe ratio. The optical reflection of this burst, reflected from a target, is then detected by an avalanche photodiode (APD). The APD’s output current drives the CurAFE, whose 4-GS/s single-bit output is processed by a digital matched filter for pulse-compression and TOF estimation through cross correlation. The 200-MHz bandwidth frontend detects bursts with bitrates up to 200 Mb/s (5-ns sub-pulsewidth) and is designed for >80-dB DR without saturation and 5-pA/ $\surd $ Hz input-referred noise. A current-feedback dc servo loop at its input cancels the background-light-induced detector current. Compared to state-of-the-art single-pulse Lidars, operating with peak optical transmit powers ~50 W, this work achieves an inaccuracy of 0.225 m (1 $\sigma $ ) over 60-m range at >10 $\times $ lower peak transmit power of ~3.5 W.

中文翻译：

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用于相位编码脉冲压缩直接飞行时间汽车激光雷达的 4-GS/s 80-dB DR 电流域模拟前端

用于相位编码脉冲压缩直接飞行时间 (dTOF) 汽车激光雷达的 4-GS/s 电流域模拟前端 (CurAFE) 已在 130-nm CMOS 中实现。允许的人眼安全激光能量以光子脉冲突发的形式传输。脉冲串嵌入了相位编码，该相位编码设计为具有最大峰值旁瓣比的自相关函数。该脉冲串的光学反射从目标反射回来，然后被雪崩光电二极管 (APD) 检测到。APD 的输出电流驱动 CurAFE，CurAFE 的 4-GS/s 单位输出由数字匹配滤波器处理，用于脉冲压缩和通过互相关估计 TOF。200-MHz 带宽前端检测比特率高达 200 Mb/s（5-ns 子脉冲宽度）的突发，专为 >80-dB DR 而设计，没有饱和和 5-pA/ $\surd $ Hz 输入参考噪声。其输入端的电流反馈直流伺服环路抵消了背景光感应的检测器电流。与最先进的单脉冲激光雷达相比，在峰值光传输功率 ~50 W 下运行，这项工作实现了 0.225 m (1 $\西格玛 $ ) 超过 60 米范围内 >10 $\times $ 较低的峰值发射功率约为 3.5 W。