128-channel high-linearity resolution-adjustable time-to-digital converters for LiDAR applications: Software predictions and hardware implementations

This paper 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 (LiDAR) 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 a good agreement and show that the proposed design has great potential for multichannel applications; the averaged DNL_(pk-pk) and INL_(pk-pk) are close to or even less than 0.05 LSB in multichannel designs.