Power-Efficient Time to Digital Converter for LiDAR
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Solution Overview
Problem
Time to digital converters (TDCs) in LiDAR systems consume excessive power, especially as applications become more complex, leading to sub-optimal power efficiency and non-linear power consumption profiles, particularly during periods of low event detection.
Innovation Solution
Implementing a power-efficient TDC system that coordinates the operation of the TDC with the LiDAR system's sampling and blanking periods by using a gating circuit to enable the clock and event detection signals only during sampling windows and disable them during blanking periods, thereby reducing unnecessary power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the TDC operates continuously to maintain readiness for photon detection, then the system can respond immediately to any detected photon, but power consumption remains high even during periods of low event detection
Solution Approach 1:
The TDC is enabled periodically during sampling windows and disabled during blanking periods between light pulses. This periodic operation allows the system to maintain readiness only when needed (during sampling windows when photons are expected) while consuming minimal power during blanking periods when no detection is occurring.
2Measurement precision
If the clock signal and event detection signals are continuously active, then the TDC can accurately time any incoming photons, but unnecessary switching occurs during blanking periods increasing power consumption
Solution Approach 1:
The clock signal and event detection signals are extracted from the continuous operation and restricted to only the sampling window periods. By removing the signals during blanking periods when they are not needed for measurement, the system maintains timing accuracy during active sampling while eliminating unnecessary power consumption during inactive periods.
3Adaptability or versatility
If the TDC operates at full capacity to handle complex LiDAR applications, then measurement capabilities are enhanced, but power consumption increases non-linearly
Solution Approach 1:
The TDC system dynamically adjusts its operational state based on the LiDAR application requirements. The gating circuit enables the TDC only during sampling windows when measurement is needed, and disables it during blanking periods. This dynamic operation allows the system to maintain full measurement capability when required while significantly improving power efficiency during periods when the TDC is not actively measuring.
Data Source
AI summary
An example method, to determine time of flight for light detection and ranging, includes enabling a time to digital converter; emitting a light pulse after enabling the time to digital converter; initiating a sampling window at a time of emission of the light pulse; using the time to digital converter to determine times of flight for photons detected during the sampling window; initiating a blanking period in response to concluding the sampling window; and disabling the time to digital converter in response to initiation of the blanking period.