Differential Amplifier Feedback for Accurate Solution Potential Sensing
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Solution Overview
Problem
Existing semiconductor devices face a trade-off between noise reduction and the number of concurrently-measurable points, with open-loop-type differential amplifiers narrowing the signal input range and reducing accuracy in amplifying and reading solution potentials.
Innovation Solution
A semiconductor device with a differential amplifier incorporating a current mirror circuit, where the reading electrode is connected to a diode-connected transistor, and the output is fed back as an input signal via a capacitor to a second input transistor, forming a closed loop to reduce amplification gain and widen the signal input range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an open-loop-type differential amplifier is used to increase the number of concurrently-measured points, then the number of concurrently-measured points increases, but the signal input range is narrowed and measurement accuracy deteriorates
Solution Approach 1:
The patent applies feedback by connecting the output terminal of the differential amplifier back to the inverting input terminal through a feedback capacitor. This feedback mechanism reduces the amplification gain of the differential amplifier, thereby expanding the signal input range and improving measurement accuracy while maintaining the ability to concurrently measure multiple points.
2Productivity
If the number of amplifiers is increased to measure multiple points concurrently, then the number of concurrently-measured points increases, but the size of each amplifier is reduced and noise increases
Solution Approach 1:
The patent merges multiple measurement functions into a single differential amplifier by using multiple reading electrodes connected to the same amplifier through the feedback mechanism. This consolidation allows one amplifier to handle multiple measurement points concurrently without requiring multiple separate amplifiers, thus avoiding the noise increase that would result from reducing individual amplifier size.
3Measurement precision
If the amplification gain is increased to amplify weak signals, then signal amplification improves, but the signal input range is narrowed
Solution Approach 1:
The feedback capacitor connected between the output and inverting input creates a feedback loop that reduces the overall amplification gain of the differential amplifier. This feedback mechanism allows the amplifier to handle a wider range of input signals while still providing sufficient amplification for weak signals, thus expanding the signal input range without completely sacrificing signal amplification capability.
Data Source
AI summary
The present disclosure relates to a semiconductor device and a cell potential measuring apparatus capable of amplifying and reading a potential of solution with high accuracy. A reading electrode reads the potential of the solution. A differential amplifier includes a current mirror circuit. The reading electrode is connected to a first input terminal of the differential amplifier which is connected to a gate of a first input transistor connected to a diode-connected pMOS transistor of the current mirror circuit. An output terminal of the differential amplifier is connected to a second input terminal of the differential amplifier, which is connected to a gate of a second input transistor connected to a pMOS transistor of the current mirror circuit which is not diode-connected, via a capacitor. For example, the present disclosure is applied to the cell potential measuring apparatus and the like.