Pixel Signal Comparator Timing to Reduce Image Sensor Power Drops
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image sensing devices face challenges in minimizing the impact of dropped source power, which affects their operational reliability and efficiency.
Innovation Solution
The implementation of an image sensing device design that includes multiple comparators and sampling circuits, where each comparator operates under distinct comparison preconditions to generate and adjust reference signals, thereby dispersing the power usage and reducing power drops across different voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple comparators operate simultaneously under the same power supply, then comparison operations can be performed in parallel improving productivity, but power drops occur affecting reliability
Solution Approach 1:
The patent divides the comparison operations into two distinct groups: anterior comparisons (pixel signal vs. ramp signal) and posterior comparisons (anterior comparison signal vs. reference signal). These groups are processed in sequential time slots rather than simultaneously, segmenting the power consumption in time domain. This allows parallel-capable operations to be performed sequentially without power conflict, maintaining reliability while preserving overall productivity.
Solution Approach 2:
The patent implements periodic alternation between anterior and posterior comparison operations. During anterior comparison period, anterior comparators are activated; during posterior comparison period, posterior comparators are activated. This periodic switching of operational phases ensures that power-consuming comparison operations are distributed over time, preventing power drops while maintaining systematic productivity.
2Device complexity
If comparators use fixed voltage levels for comparison, then device complexity is reduced, but adaptability to different power conditions deteriorates
Solution Approach 1:
The patent introduces dynamic voltage level adjustment for reference signals in posterior comparisons. The reference signal voltage is no longer fixed but is dynamically adjusted based on the actual power supply conditions detected during operation. This allows the comparison threshold to adapt to varying power levels, maintaining comparison accuracy across different power conditions without significantly increasing device complexity through software or control logic.
Solution Approach 2:
The patent changes the voltage level parameter of reference signals adaptively based on power conditions. When power supply voltage varies, the reference signal voltage is adjusted proportionally or according to predefined calibration data, ensuring that comparison operations remain accurate despite power fluctuations. This parameter adaptation enables the system to handle diverse power conditions without requiring complex hardware reconfiguration.
Data Source
AI summary
An image sensing device includes first and anterior comparators and first and second posterior comparators. The first anterior comparator generates a first anterior comparison signal based on a first pixel signal and a ramp signal. The first posterior comparator performs a first comparison that compares the first anterior comparison signal with a first reference signal under a first comparison precondition and generates a first posterior comparison signal corresponding to a result of the first comparison. The second anterior comparator generates a second anterior comparison signal based on a second pixel signal and the ramp signal. The second posterior comparator performs a second comparison that compares the second anterior comparison signal with a second reference signal under a second comparison precondition different from the first comparison precondition. The second posterior comparator generates a second posterior comparison signal corresponding to a result of the second comparison.