CMOS Image Sensor Low-Power Multi-Mode Data Path
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Solution Overview
Problem
Conventional CMOS Image Sensors (CIS) face challenges in reducing power consumption while maintaining high signal-to-noise ratio (SNR) and dynamic range, especially when operating continuously, leading to increased dark current and noise characteristics due to rising sensor temperatures, and inefficient data processing that wastes dynamic current.
Innovation Solution
A low power multi-mode data path is implemented in the CIS system, utilizing a pixel array with 4-shared pixel arrays, a data arrangement unit for merging and rearranging pixel data, and a data transmitting unit that divides and transmits data efficiently, reducing transitions and power consumption through exclusive-OR operations and sharing static current among stacked drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional CIS performs data processing regardless of pixel data characteristics, then data processing is simplified, but dynamic current is wasted and power consumption increases
Solution Approach 1:
The patent applies local quality by differentiating data processing based on pixel data characteristics. Different processing paths are used for different types of pixel data (e.g., saturated pixels, dark current affected pixels, normal pixels), allowing the system to process each type appropriately rather than using a uniform approach. This reduces unnecessary processing for certain data types while maintaining quality where needed.
Solution Approach 2:
The patent changes processing parameters based on pixel data characteristics. By detecting specific conditions in pixel data (such as saturation levels, dark current patterns), the system dynamically adjusts processing intensity and methods, thereby optimizing power consumption while maintaining image quality where necessary.
2Productivity
If CIS operates continuously to obtain continuous image information, then image information availability is improved, but sensor temperature rises causing dark current increase and noise deterioration
Solution Approach 1:
The patent implements periodic action by enabling the image sensor to operate in continuous mode while periodically managing temperature and dark current effects through specific processing techniques. The system continuously acquires images but applies periodic correction for dark current and noise based on detected patterns, allowing continuous operation without cumulative temperature damage.
Solution Approach 2:
The patent converts the harmful effect of continuous operation (temperature rise and dark current) into a detectable pattern that can be corrected. By analyzing dark current patterns and temperature effects, the system identifies and compensates for these harmful effects through image processing, turning what would be degradation into an correctable artifact.
3Measurement precision
If conventional CIS prioritizes high SNR and dynamic range, then image quality is improved, but power consumption becomes excessive for long-term operation
Solution Approach 1:
The patent applies partial action by not always using full-power processing for all pixels. Instead, it processes only the necessary portions of image data at high precision (when needed for quality) and uses reduced processing for other portions, thereby maintaining acceptable image quality while significantly reducing overall power consumption for long-term operation.
Data Source
AI summary
Provided are a CIS system and a method of processing the same using a low power multi-mode data path. In order to drive a circuit with low-power, the CMOS Image Sensor (CIS) system rearranges and transmits data in consideration of a color of pixel data and a most significant bit (MSB) and a least significant bit (LSB) of the pixel data using a low-power multi-mode data path. The CIS system can implement multi-modes including a low power mode and a high speed mode, reduce the number of data transitions by merging data of the same color in a always-on low-power mode and a photo-shooting low-power (PS-LP) mode to reduce power consumption and process data in a high speed using a pipeline in a photo-shooting high-speed (PS-HS) mode.