Fingerprint Image Sensor Signal Averaging for Lower Area and Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image sensors face challenges in reducing area and power consumption, particularly due to the need for a large number of output and sampling circuits for signal combination and averaging, which increases their size and energy requirements.
Innovation Solution
The image sensor design includes a pixel circuit array where each pixel generates an output signal, and an output circuit that simultaneously receives and averages the signals from multiple pixel circuits, reducing the number of necessary output and sampling circuits through row and column scanning, and incorporating an operational amplifier and sampling circuit for correlated double sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of output circuits are used for signal combination and averaging, then signal processing capability is improved, but area and power consumption increase
Solution Approach 1:
Multiple pixel circuits share a single output circuit for signal combination and averaging. The output circuit receives signals from multiple pixel circuits, combines them, and outputs the average value, thereby reducing the total number of output circuits needed while maintaining signal processing capability.
Solution Approach 2:
The output circuit is designed to handle multiple functions: receiving signals from multiple pixel circuits, combining the signals, calculating the average value, and outputting the result. This multi-functional design eliminates the need for separate dedicated circuits for each pixel.
2Reliability
If a large number of sampling circuits are used for signal collection, then signal acquisition capability is improved, but area and power consumption increase
Solution Approach 1:
Multiple pixel circuits share a single sampling circuit for signal collection. The sampling circuit sequentially or simultaneously samples the output signals from multiple pixel circuits, reducing the total number of sampling circuits required while maintaining comprehensive signal acquisition capability.
3Measurement precision
If multiple dedicated output circuits are used for each pixel circuit, then signal processing precision is improved, but device complexity increases
Solution Approach 1:
The output circuit integrates multiple signal processing functions (signal reception, combination, averaging, and output) into a single unified circuit block, reducing device complexity while maintaining signal processing precision through careful circuit design.
Solution Approach 2:
The output circuit acts as an intermediary between multiple pixel circuits and the external world, performing all necessary signal processing operations in between. This mediator approach simplifies the overall system architecture by eliminating the need for each pixel circuit to have its own dedicated output path.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the area and power consumption of the image sensor by minimizing the number of output and sampling circuits required, while enabling efficient signal combination and averaging, and improving performance by eliminating reset noise.
Implementation Method 1
the output circuit is configured to simultaneously receive output signals of a plurality of pixel circuits in the pixel circuit array, and output a signal average value of the output signals of the plurality of pixel circuits
Implementation Method 2
a sampling circuit, configured to collect the signal average value output by the output circuit
Implementation Method 3
incorporating an operational amplifier and sampling circuit for correlated double sampling
Data Source
AI summary
An image sensor, a fingerprint detection apparatus, and an electronic device are provided. The image sensor includes a pixel circuit array, wherein each pixel circuit is configured to generate an output signal according to a received light signal; and an output circuit is configured to simultaneously receive output signals of a plurality of pixel circuits in the pixel circuit array, and output a signal average value of the output signals of the plurality of pixel circuits. The image sensor has a small area and power consumption.