128-Channel High-Linearity Resolution-Adjustable Time-to-Digital Converters for LiDAR Applications: Software Predictions and Hardware Implementations

This article proposes a new calibration method, called the mixed-binning (MB) method, to pursue high-linearity time-to-digital converters (TDCs) for light detection and ranging applications. The proposed TDCs were developed using tapped delay-line (TDL) cells in field-programmable gate arrays (FPGAs). With the MB method, we implemented a resolution-adjustable TDC showing excellent linearity in Xilinx UltraScale FPGAs. We demonstrate a 128-channel TDC to show that the proposed method is cost-effective in logic resources. We also developed a software tool to predict the performances of TDL-based TDCs robustly. Results from both software analysis and hardware implementations are in good agreement and show that the proposed design has great potential for multichannel applications; the averaged
${{\bf DN}}{{{\bf L}}_{{\boldsymbol{pk}} - {\boldsymbol{pk}}}}$
and
${{\bf IN}}{{{\bf L}}_{{\boldsymbol{pk}} - {\boldsymbol{pk}}}}$
are close to or even less than 0.05 LSB in multichannel designs.