Charge Amplifier Drift Reduction via Potential Control
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Solution Overview
Problem
Existing charge amplifiers suffer from drift issues, where the output of the integrating circuit changes over time, leading to saturation and reduced functionality, despite efforts to mitigate this with compensating currents through diodes or capacitors, which are prone to manufacturing variations and temperature changes.
Innovation Solution
A charge amplifier design that includes a first and second conductive member with an insulating member in between, a potential controlling voltage signal circuit, and a temperature detection circuit to adjust the potential of the second conductive member, reducing the influence of drift by controlling the potential difference between the conductive members and using a metal interconnect and impurity regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compensating current is supplied through a diode or capacitor to reduce drift, then the influence of drift is reduced, but the compensating current magnitude changes due to manufacturing variations and temperature changes
Solution Approach 1:
The patent introduces a third conductive member as an intermediary element between the first and second conductive members. This third conductive member serves as a mediator to control the potential distribution, allowing the system to reduce drift influence without relying on temperature-sensitive components like diodes or capacitors. The intermediary structure enables stable compensating current through geometric and potential control rather than through temperature-vulnerable electronic components.
Solution Approach 2:
The patent changes the approach from using temperature-sensitive component characteristics (diode forward voltage, capacitor leakage) to controlling the electrical potential parameter directly. By applying a controlled potential to the third conductive member and controlling the potential difference between conductive members, the system achieves stable compensating current that is insensitive to temperature variations and manufacturing tolerances.
2Productivity
If the integrating circuit operates continuously, then charge signals are converted to voltage signals, but drift causes the output to saturate and the circuit to malfunction
Solution Approach 1:
The patent applies preliminary action by controlling the potential distribution before drift can cause saturation. The third conductive member is used to pre-establish a controlled potential environment that prevents drift-induced saturation from occurring in the first place. This proactive potential control ensures the integrating circuit can operate continuously without reaching saturation, maintaining both productivity and reliability.
3Reliability
If the potential of conductive members is controlled to reduce drift, then drift influence is minimized, but additional control circuits are required
Solution Approach 1:
The patent merges the drift compensation function with the existing conductive structure of the charge amplifier. Instead of adding separate control circuits, the third conductive member is integrated into the existing architecture, combining the signal transmission path with the drift compensation mechanism. This merging approach achieves reliable drift compensation while minimizing additional device complexity.
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
The solution effectively reduces the impact of drift on the charge amplifier's output, ensuring continuous functionality and accuracy by dynamically adjusting the potential differences between conductive members, thereby minimizing the effects of manufacturing variations and temperature changes.
Implementation Method 1
an insulating member provided between the first conductive member and the second conductive member
Implementation Method 2
a potential controlling voltage signal output circuit configured to supply a potential controlling voltage signal to the second conductive member
Data Source
AI summary
A charge amplifier that converts a charge signal to a voltage signal includes: a first conductive member through which the charge signal propagates; a second conductive member that is provided along at least a portion of the first conductive member; an insulating member provided between the first conductive member and the second conductive member; a potential controlling voltage signal output circuit that is connected to the second conductive member, and is configured to supply a potential controlling voltage signal to the second conductive member; and an integrating circuit that includes an input terminal and an output terminal, the input terminal being connected to the first conductive member, and is configured to output the voltage signal from the output terminal.