Strobing Flash Lidar Control Circuit Power Optimization
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Solution Overview
Problem
Power consumption and heat generation in Time of Flight (ToF) based LIDAR systems, particularly in applications like UAVs, automotive, and industrial robotics, pose challenges due to increased emission power requirements, affecting optical performance and reliability.
Innovation Solution
A LIDAR system with a control circuit that selectively operates subsets of emitter and detector units, optimizing power levels and activation durations to reduce average power usage, using shared memory locations and PRMW operations to store count data based on elapsed time from emission pulses, and activating detectors for extended periods to capture signals across multiple distance sub-ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the emitter units operate continuously at high power to ensure sufficient emission for detection, then the detection capability is improved, but the power consumption increases and heat generation affects optical performance and reliability
Solution Approach 1:
The patent applies periodic action by operating the emitter units in pulsed mode rather than continuously. The control circuit selectively activates emitter units for specific time intervals corresponding to different distance sub-ranges, allowing the system to maintain detection capability while significantly reducing average power consumption and heat generation.
Solution Approach 2:
The patent segments the detection range into multiple distance sub-ranges, with each sub-range handled by specific emitter units during specific time intervals. This segmentation allows the system to activate only the necessary emitter units for each measurement, reducing overall power consumption while maintaining full-range detection capability.
2Use of energy by moving object
If the detector pixels are activated for short durations to reduce power consumption, then the power usage is reduced, but the ability to capture signals across multiple distance sub-ranges is limited
Solution Approach 1:
The control circuit activates different detector pixels periodically for different distance sub-ranges. By cycling through multiple activation patterns across several measurement cycles, the system captures signals from all distance sub-ranges while keeping individual detector activation durations short, thus reducing power consumption.
Solution Approach 2:
The patent merges data from multiple detector pixels activated at different times to reconstruct complete depth information for all distance sub-ranges. By combining measurements taken during different activation cycles, the system achieves comprehensive coverage without requiring all detectors to be active simultaneously.
3Loss of information
If all detector pixels are activated simultaneously to capture all distance information, then the completeness of depth data is improved, but the power consumption and complexity of data processing increase
Solution Approach 1:
The patent segments the depth measurement process into multiple time intervals, with each interval dedicated to a specific distance sub-range. This temporal segmentation allows the system to process data in smaller, more manageable chunks rather than handling all detector data simultaneously, reducing processing complexity.
Solution Approach 2:
The control circuit prepares and organizes count data from detector pixels according to their corresponding distance sub-ranges before full processing. By preliminarily sorting and organizing data during the measurement cycles, the system reduces the complexity of subsequent processing steps while maintaining complete depth information.
4Measurement precision
If the emission power is increased to improve signal-to-noise ratio, then the detection accuracy is improved, but the heat generation negatively affects reliability and optical performance
Solution Approach 1:
The system uses periodic pulsed emission with high peak power during active intervals followed by idle periods. This allows the emitter to achieve high signal-to-noise ratio during detection intervals while the average power remains low, preventing heat-related degradation and maintaining reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces average power consumption while maintaining signal-to-noise ratio, improving reliability and optical performance by minimizing idle periods and optimizing data storage and processing.
Implementation Method 1
an emitter configured to emit a plurality of optical signals, a detector configured to be activated to detect one of the optical signals in light that is incident on the detector
Implementation Method 2
Direct time of flight measurement includes directly measuring the length of time between emitting radiation and sensing the radiation after reflection from an object or other target
Implementation Method 3
A SPAD is based on a p-n junction device biased beyond its breakdown region, for example, by or in response to a strobe signal having a desired pulse width. The high reverse bias voltage generates a sufficient magnitude of electric field such that a single charge carrier introduced into the depletion layer of the device can cause a self-sustaining avalanche via impact ionization
Implementation Method 4
The initiating charge carrier can be photo-electrically generated by means of a single incident photon striking the high field region
Data Source
AI summary
A Light Detection and Ranging (lidar) system, includes an emitter configured to emit a plurality of optical signals, a detector configured to be activated to detect one of the optical signals in light that is incident on the detector and to provide count data corresponding to the one of the optical signals that were detected, a plurality of storage memory locations configured to store the count data therein, and a control circuit configured to change a location at which the count data is stored from a first storage memory location to a second storage memory location based on an elapsed time duration from an emission of the one of the optical signals.