Electrochemical Sensor Bias Circuit With Coupled Inputs for Noise Reduction
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Solution Overview
Problem
Conventional electrochemical sensor circuits face challenges in reducing noise interference, which affects the precision and reliability of chemical concentration measurements, particularly due to noise generated by reference signals in amplifiers.
Innovation Solution
The proposed solution involves an interface circuit configuration where the non-inverting input of a first amplifier is directly coupled to the inverting input of a second amplifier, effectively eliminating noise by creating a virtual short, and optionally includes a diode network in the feedback path of the second amplifier for dynamic gain adjustment to prevent saturation during sudden signal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional amplifier configurations are used in electrochemical sensor circuits, then the circuit can provide basic signal amplification, but noise interference from reference signals degrades measurement precision
Solution Approach 1:
The patent merges the reference signal inputs of two amplifiers by directly coupling the non-inverting input of the first amplifier to the inverting input of the second amplifier. This merging causes the noise from both amplifiers to appear at the same potential, eliminating noise currents and significantly reducing noise interference in the measurement signal.
Solution Approach 2:
The direct coupling between amplifier inputs creates a virtual short that establishes equipotential conditions. By making the reference signal inputs equipotential, the patent eliminates potential differences that would otherwise drive noise currents, thereby improving measurement precision.
2Reliability
If fixed gain amplification is used, then the circuit design is simple, but the amplifier saturates during sudden signal changes causing loss of measurement accuracy
Solution Approach 1:
The patent introduces dynamic gain adjustment capability to the amplifier circuit. The gain can be adjusted in real-time based on signal conditions, allowing the circuit to handle sudden signal changes without saturation while maintaining simplicity during normal operation. This dynamic adaptation improves reliability without excessive complexity.
Solution Approach 2:
The patent changes the gain parameter of the amplifier dynamically rather than using a fixed value. By allowing the gain parameter to adapt to varying signal conditions, the circuit maintains measurement accuracy during both small and large signal variations without requiring overly complex circuit architecture.
Data Source
AI summary
Techniques for improving noise performance while processing signals received from an electrochemical sensor are provided. In an example, an interface circuit can include a first amplifier configured to provide a voltage to a counter electrode of an electrochemical sensor, a second amplifier configured to receive sensor information from a working electrode of the electrochemical sensor and to provide concentration information using the sensor information. In certain examples, an input of the first amplifier can be directly coupled to an input of the second amplifier to attenuate noise, of either the first amplifier or the second amplifier, within the concentration information provided by the second amplifier.