Clock-Gated Latch for Time-of-Flight Camera Signal Synchronicity
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Solution Overview
Problem
Time-of-flight cameras face challenges in synchronicity of signal transmission due to the large number of pixels, leading to issues with rising and falling times of demodulation signals, which affect the ability of demodulation drivers to properly drive pixels, especially in large pixel arrays.
Innovation Solution
The implementation of a clock-gated latch between routing wires that transport demodulation signals from a demodulation driver to pixels in a pixel column, which improves the fall time of demodulation signals by reducing the RC time constant and promoting faster toggling of complementary clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in a ToF camera is increased to improve imaging resolution, then the imaging quality is improved, but the synchronicity of signal transmission deteriorates due to the large number of pixel rows and columns
Solution Approach 1:
The pixel array is divided into multiple pixel columns, each with its own dedicated demodulation driver. This segmentation allows independent signal transmission control for each column, improving synchronicity while maintaining high pixel counts for good imaging resolution.
Solution Approach 2:
A clock-gated latch is introduced as an intermediary component between the demodulation driver and the pixels. This latch acts as a buffer that improves signal toggling speed and reduces RC time constants, thereby enhancing signal transmission synchronicity without compromising pixel density.
2Measurement precision
If the pixel array size is increased to improve imaging capability, then the imaging performance is improved, but the driving ability of demodulation drivers deteriorates due to increased current load
Solution Approach 1:
The demodulation driver circuit is segmented into column-specific units, each driving a dedicated pixel column. This distribution of driving responsibility reduces the current load on each individual driver, maintaining driving ability while supporting large pixel arrays for improved imaging performance.
Solution Approach 2:
The clock-gated latch serves as an intermediary that reduces the current load on demodulation drivers by improving signal toggling efficiency and reducing RC time constants. This allows drivers to maintain adequate driving ability even when connected to large numbers of pixels for high-resolution imaging.
3Measurement precision
If the pixel array is enlarged to improve imaging resolution, then the imaging quality is improved, but the rising and falling times of demodulation signals increase due to larger RC time constants
Solution Approach 1:
A clock-gated latch is inserted as an intermediary between the demodulation driver and pixel columns. This latch actively drives the signal with reduced RC time constants, achieving faster rising and falling times that enable high-speed operation in large pixel arrays while maintaining the imaging resolution benefits of large sensor size.
Data Source
AI summary
An electronic device comprising a clock-gated latch between two routing wires which transport a demodulation signal from a demodulation driver to pixels of a pixel column of a pixel array.