Amplifier Circuit With MOS Capacitors for Dark Noise Compensation

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Solution Overview

Problem

Radiation detectors are adversely affected by dark noise, which complicates accurate signal detection, and existing compensation methods are inadequate.

Innovation Solution

An amplifier system with an adjustable current source and MOS capacitors is employed to compensate for dark noise by feeding a counteracting current, utilizing a processor to determine the compensation signal based on the detector's output and thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an amplifier is used to detect radiation signals, then the detection capability is improved, but dark noise adversely affects measurement precision

Engineering Contradiction:
Improveradiation signal detection accuracyVSAvoiddark noise impact
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by introducing a compensation current source that generates a current equal in magnitude but opposite in direction to the dark noise current. This compensating current is injected into the amplifier input before the dark noise affects the measurement, effectively canceling out the harmful dark noise effect and improving measurement precision without sacrificing detection capability

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful dark noise into a beneficial effect by measuring the dark noise current separately using a dedicated compensation current source, then using this measured dark noise information to generate a compensating signal. The harmful dark noise current is transformed into useful compensation data that improves the overall measurement accuracy

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If a compensation current source is added to reduce dark noise, then dark noise compensation capability is improved, but device complexity increases

Engineering Contradiction:
Improvedark noise compensationVSAvoidamplifier circuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by separating the dark noise compensation function from the main amplification function. A dedicated compensation current source is implemented as an independent module with its own current mirror circuitry, allowing it to operate separately from the main signal amplification path. This modular segmentation enables effective dark noise compensation while maintaining clear functional separation and manageable circuit complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compensation current source is designed with multi-functionality, serving both as a dark noise measurement device and as a compensation signal generator. The same circuit structure performs multiple functions: measuring dark noise current, generating compensating current, and injecting it into the amplifier input, thereby reducing overall device complexity despite adding compensation capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4004604B1Amplifier for dark noise compensation
Publication Date: 2025.07.02 SHENZHEN XPECTVISION TECH CO LTD
  • EP4004604B1 patent drawingFigure 1A~1C
  • EP4004604B1 patent drawingFigure 1D~1G
  • EP4004604B1 patent drawingFigure 2~3A

AI summary

An amplifier (309), comprising: an op-amp (391) configured to receive at an input thereof a first electric current; a first MOS capacitor (393) connected to the input and an output of the op-amp (391).