Complementary Sensor Interface Circuit for Differential Signal Amplification
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Solution Overview
Problem
Conventional sensor circuits, particularly those using resistor-type and TFT-type sensors, face limitations in sensitivity enhancement due to fixed resistor configurations and uniform current change responses, which hinder effective signal amplification and stability in Internet of Things environments.
Innovation Solution
A complementary sensors-integrated interface circuit is proposed, combining FET-type and resistor-type sensors with complementary sensing characteristics, configured in series to amplify current changes into voltage outputs, and a differential amplifier circuit is used to further enhance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed resistor is used as a load in the interface circuit, then the circuit structure is simple, but the sensitivity cannot be maximized because the load resistance must be adjusted according to the sensor response degree
Solution Approach 1:
The patent replaces the fixed resistor with a TFT element that dynamically adjusts its resistance based on the detection target concentration. The TFT element's threshold voltage changes in response to the detection target, automatically optimizing the load resistance to match the sensor response degree, thereby maximizing sensitivity without requiring manual adjustment or complex circuit structures.
Solution Approach 2:
The patent changes the resistance parameter of the load element from a fixed value to a variable value that responds to the detection target. By using a TFT element whose electrical characteristics change in response to the detection target, the circuit automatically optimizes its operating parameters to maximize detection sensitivity under different conditions.
2Use of energy by moving object
If a TFT-type sensor with fixed resistor or TFT element load is used, then the circuit can operate with low power, but the sensitivity cannot be increased because both the sensor and load respond to the detection target in the same direction
Solution Approach 1:
The patent introduces a complementary sensor that responds to the detection target in the opposite direction to counterbalance the response of the first sensor. By connecting sensors with opposite response characteristics (one increases output with detection target, the other decreases output), the circuit achieves enhanced sensitivity through differential measurement while maintaining low power consumption, as the opposing responses amplify the detection signal.
3Productivity
If resistor-type sensor with fixed resistor load is used, then the manufacturing process is simple and large amount of sensors can be produced, but the noise is very large and reliability and durability are limited
Solution Approach 1:
The patent replaces the resistor-type sensor's direct resistance measurement mechanism with a FET-type sensor that measures electrical field effects. The FET sensor separates the sensing material from the signal readout path, substituting the direct electrical contact method with a field-effect-based measurement, thereby reducing noise and improving reliability while maintaining compatibility with standard semiconductor manufacturing processes.
Data Source
AI summary
Provided is a complementary sensors-integrated interface circuit and a differential circuit using the same. The complementary sensors-integrated interface circuit includes: a first sensor having a sensing characteristic for a detection target material; and a second sensor having a sensing characteristic complementary to that of the first sensor for the detection target material, wherein the first sensor is composed of an FET-type sensor, the second sensor is composed of an FET-type sensor or a resistor-type sensor, and the first sensor and the second sensor are connected in series. The interface circuit having the above-described configuration increases the change in output voltage, thereby improving the sensing sensitivity. The complementary sensors-integrated interface circuit is characterized in that it serves as an amplification circuit. In addition, a complementary sensors-integrated differential interface circuit uses the aforementioned complementary sensors-integrated interface circuit, thereby serving as a differential amplifier circuit, reducing noise and improving sensitivity.