Image Sensor Power Management Chopping for Low-Frequency Noise
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Solution Overview
Problem
Existing image sensors face challenges in reducing noise in power supply voltages, particularly low-frequency noise within the amplifier of the power management module, which affects image quality.
Innovation Solution
The implementation of a power management module with chopping circuits that modulate and demodulate input signals to reduce noise, using a first chopping circuit to modulate the input signal, an amplifier to generate an output signal, and a second chopping circuit to demodulate and reduce noise caused by the amplifier, with a timing controller generating clock and inverse clock signals to control these circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chopping circuits are added to reduce low-frequency noise, then noise reduction performance is improved, but device complexity increases
Solution Approach 1:
The patent combines the chopping circuit functionality with the existing power management module structure. By integrating the chopping operation into the current circuit architecture rather than adding completely separate components, the patent reduces the overall complexity increase while achieving noise reduction.
Solution Approach 2:
The chopping circuit is designed to perform multiple functions: it modulates the low-frequency noise to higher frequencies, enables noise filtering through frequency separation, and maintains compatibility with the existing power management module operation. This multi-functionality reduces the need for additional dedicated components.
Data Source
AI summary
An image sensor includes a pixel array including a plurality of pixel groups arranged in a plurality of rows and columns, the plurality of pixel groups configured to convert a light into electrical signals and to generate pixel signals, a row driver configured to generate a plurality of control signals for controlling the rows of the pixel array, and one or more power management devices configured to generate a power supply voltage for generating the plurality of control signals based on an input signal, and supply the power supply voltage to the row driver. Each of the one or more power management devices includes a first chopping circuit configured to modulate the input signal, an amplifier configured to generate an output signal based on the modulated input signal, and a second chopping circuit configured to demodulate the output signal and to modulate a noise caused by the amplifier.