Sub-Ranging PGA for Faster Low-Power Pixel ADC Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated-circuit image sensors face challenges in efficiently amplifying and converting pixel signals into digital data due to the high voltage-ramp span required for analog-to-digital conversion, leading to increased power consumption and noise suppression time.
Innovation Solution
A sub-ranging programmable gain amplifier (PGA) dynamically steps down amplified pixel signals into multiple amplitude sub-ranges, reducing the voltage-ramp span for single-slope analog-to-digital conversion, enabling faster and lower power conversion while maintaining noise reduction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high voltage-ramp span is used for analog-to-digital conversion to cover the full dynamic range of pixel signals, then conversion accuracy is improved, but power consumption and conversion time increase significantly
Solution Approach 1:
The patent divides the full dynamic range of pixel signals into multiple sub-ranges, each requiring a smaller voltage-ramp span for conversion. By segmenting the signal range and processing signals in groups within the same sub-range, the system achieves accurate conversion with reduced ramp spans, thereby lowering power consumption while maintaining conversion precision for each segment.
2Measurement precision
If a high voltage-ramp span is used for analog-to-digital conversion, then conversion accuracy is improved, but conversion time increases
Solution Approach 1:
The patent segments pixel signals into multiple sub-ranges based on their amplitude levels. Each sub-range requires a shorter voltage-ramp span for conversion, enabling faster conversion times. By processing signals in segmented groups rather than requiring a single large ramp span, the system achieves both accurate conversion and reduced conversion time.
3Adaptability or versatility
If multiple amplification stages are used to handle the full dynamic range, then signal coverage is improved, but device complexity increases
Solution Approach 1:
The patent employs a dynamic sub-range selection mechanism that automatically identifies and groups pixel signals into appropriate sub-ranges based on their amplitude levels. This dynamic approach allows a single amplifier structure to handle the full dynamic range by adaptively adjusting the conversion parameters for different signal groups, eliminating the need for multiple fixed amplification stages and reducing overall device complexity.
Data Source
AI summary
A sub-ranging programmable gain amplifier resolves an incoming signal into one of multiple amplitude sub-ranges and dynamically steps down the PGA output according to the identified sub-range.