Image Sensor Counter Unit Power Optimization
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Solution Overview
Problem
Image sensors face challenges in achieving high image resolution while minimizing power consumption, particularly in mobile devices where power efficiency is crucial.
Innovation Solution
The implementation of a counter unit with a mask counter and remaining counters that perform counting operations during specific sections of the counter enable period, reducing the overall number of counting operations and thus power consumption, while maintaining high image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all counters perform counting operations during the entire counter enable period, then high image resolution is achieved, but power consumption increases
Solution Approach 1:
The counter enable period is divided into multiple sections (first section, second section, third section), and different counters are selectively enabled in different sections. This segmentation allows the system to achieve high image resolution by using all counters when needed while reducing power consumption by using fewer counters in other sections.
Solution Approach 2:
The system dynamically adjusts which counters are active based on the timing section. The mask counter is selectively enabled or disabled depending on whether the current timing is in the first section or second/third sections, allowing flexible adaptation between resolution requirements and power consumption constraints.
2Device complexity
If the ramp signal has a decreasing slope throughout the entire ramp signal enable period, then simple circuit design is maintained, but the ability to reduce power consumption is limited
Solution Approach 1:
The ramp signal generator dynamically changes the slope of the ramp signal based on the timing section. During the first section, the ramp signal has a first slope, and during the second section, it has a second slope that is different from the first. This dynamic adjustment allows power consumption reduction without significantly complicating the circuit design.
Data Source
AI summary
An image sensor includes; a sensor array generating a pixel signal, a ramp signal generator generating a ramp signal having a decreasing slope during a ramp signal enable period between a first time at which a counter enable signal is activated and a third time at which the ramp signal ends falling, a comparator comparing the pixel signal with the ramp signal to trigger an output signal, and counters, where at least one of the counters performs counting during an entire counter enable period extending between the first time and a second time at which the comparator triggers the output signal, but not all of the counters perform counting during at least one section of the counter enable period.