Pipelined Histogram Pixel for Lower-Power ToF LiDAR
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Solution Overview
Problem
Existing LIDAR systems face inefficiencies in memory resource utilization due to sparsely occupied histogram bins and high power consumption in memory storage operations, particularly in ToF LIDAR systems, which are exacerbated by layout limitations and speed requirements.
Innovation Solution
Implementing pipelined memory storage operations, where data is stored in a temporary buffer memory during a strobe window and integrated into a main memory at a lower clock rate during the remainder of the emitter pulse cycle, decoupling sampling and integration processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If memory storage operations are performed at high clock rates to meet speed requirements, then processing speed is improved, but power consumption increases
Solution Approach 1:
The patent divides memory storage operations into two distinct phases: a first mode for high-speed data input during the strobe window, and a second mode for lower-speed integration into histogram bins during the remainder of the emitter pulse cycle. This segmentation allows the system to achieve high processing speed when needed while reducing power consumption during less critical operations, directly resolving the contradiction between speed and power usage.
Solution Approach 2:
The patent implements dynamic clock rate adjustment by operating the memory device at a first clock rate during the strobe window and a second, lower clock rate during the remainder of the emitter pulse cycle. This dynamic adaptation of operating parameters enables the system to optimize the balance between processing speed and power consumption based on the specific operational phase, rather than maintaining a fixed high-speed operation that would continuously consume high power.
2Measurement precision
If memory depth is increased to cover full time range with high resolution, then measurement precision is improved, but memory resource utilization efficiency deteriorates
Solution Approach 1:
The patent segments the time range into a strobe window period and a remainder period, assigning different memory operations to each segment. During the strobe window, high-resolution timestamp data is captured with fine time bins. During the remainder period, data is integrated into coarser histogram bins. This segmentation allows the system to maintain high measurement precision for critical photon arrival time data while improving memory resource utilization by using coarser bins for less critical integration operations.
Solution Approach 2:
The patent applies different memory bin resolutions to different temporal regions: fine time bins are used during the strobe window where precise photon arrival time measurement is critical, while coarser histogram bins are used during the remainder of the emitter pulse cycle where lower precision is acceptable. This local differentiation of quality parameters enables the system to maintain high measurement precision where needed while improving overall memory resource utilization efficiency.
Data Source
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AI summary
A Light Detection and Ranging (LIDAR) detector circuit includes a memory device comprising a first memory and a second memory, and at least one control circuit. The at least one control circuit is configured to execute first memory storage operations to store data indicated by detection signals received from one or more photodetector elements in the first memory during a first portion of a time between pulses of an emitter signal output from a LIDAR emitter element, and to execute second memory storage operations to include the data, which was stored in the first memory, in the second memory during a second portion of the time between the pulses of the emitter signal. Related devices and methods of operation are also discussed.