Photoelectric Conversion Device Temperature Compensation Circuit
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Solution Overview
Problem
The resistance value of the resistive element in photoelectric conversion devices changes with internal temperature, affecting the current flowing through it and resulting in variations in pixel values even when the same voltage is applied, leading to inconsistent data signals.
Innovation Solution
Incorporating a temperature detection circuit that generates an analog output corresponding to the internal temperature, which adjusts the gain of the A/D converter to minimize the impact of temperature changes on pixel values by using a second resistive element with similar temperature characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistive element is used to convert voltage difference into current for pixel value output, then the data signal can be read out, but the resistance value changes with internal temperature causing pixel value variations
Solution Approach 1:
The patent changes the operating parameters of the A/D converter based on temperature detection. The conversion gain is adjusted according to the internal temperature to compensate for resistance changes in the resistive element, maintaining consistent pixel values across different temperature conditions
Solution Approach 2:
The patent implements a feedback mechanism where the internal temperature is continuously detected and used to adjust the A/D converter gain. This closed-loop control compensates for resistance drift and maintains measurement precision
2Measurement precision
If the A/D converter gain is adjusted to compensate for temperature changes, then pixel value consistency is improved, but device complexity increases
Solution Approach 1:
The temperature detection circuit serves multiple functions: it detects internal temperature, determines the appropriate gain setting, and controls the A/D converter adjustment. This multi-functionality reduces the need for separate compensation circuits
Solution Approach 2:
Instead of adding complex hardware compensation circuits, the patent achieves temperature compensation by dynamically changing the A/D converter gain parameter based on temperature detection, simplifying the overall device structure
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 solution effectively reduces the variation in pixel signals caused by temperature changes, ensuring consistent data output by compensating for resistance value changes in the resistive element, thereby stabilizing the photoelectric conversion device's performance.
Implementation Method 1
a first resistive element to which a voltage corresponding to a difference between the data signal held by the first hold circuit and the noise signal held by the second hold circuit is applied
Implementation Method 2
a temperature detection circuit configured to generate, based on a current flowing in the second resistive element, an analog output corresponding to an internal temperature of the photoelectric conversion device
Implementation Method 3
light receiving circuit configured to convert light into an electrical signal
Data Source
AI summary
A photoelectric conversion device includes a light receiving circuit configured to convert light into an electrical signal, a first hold circuit configured to hold a data signal which represents the electrical signal, a second hold circuit configured to hold a noise signal read out from the light receiving circuit in a reset state, a first resistive element to which a voltage corresponding to a difference between the data signal held by the first hold circuit and the noise signal held by the second hold circuit is applied, an A/D converter configured to convert an analog current flowing in the first resistive element into digital data, a second resistive element, and a temperature detection circuit configured to generate, based on a current flowing in the second resistive element, an analog output corresponding to an internal temperature of the photoelectric conversion device.