Electrochemical Gas Sensor Circuit for Powered-Off Current Grounding
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Solution Overview
Problem
Conventional electrochemical gas sensors face issues with background current generation when powered off, leading to potential disturbances at the reference electrode, and require transistors that cannot operate at lower voltages for miniaturization, causing operational challenges.
Innovation Solution
The proposed sensing system includes an electronic circuit with first and second switching elements, electrically coupled to the reference and sensing terminals of the electrochemical gas sensor, which connect these terminals to a ground voltage terminal when the sensor is powered off, maintaining equal potentials and grounding any generated current, and uses transistors with gate terminals coupled to a voltage source through diodes or capacitive elements to prevent damage and allow operation at lower voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electrochemical gas sensor is powered off, then energy consumption is reduced, but background current is generated at the sensing electrode which disturbs the reference electrode
Solution Approach 1:
A switching element is introduced as an intermediary component between the sensing electrode and the reference electrode. This switch acts as a mediator that can selectively connect or disconnect the sensing electrode from the reference electrode based on the power state, thereby preventing background current from disturbing the reference electrode when the sensor is powered off.
Solution Approach 2:
The switching element is configured to automatically connect the sensing electrode to the reference electrode when the sensor is powered off, before any background current can accumulate and cause disturbance. This preliminary action ensures that any electrochemical reactions occurring during the powered-off state are immediately referenced, preventing potential disturbances.
2Reliability
If conventional transistors are used in the electronic circuit, then the circuit can operate at standard voltages, but the sensor cannot be miniaturized due to voltage requirements
Solution Approach 1:
The patent changes the operating voltage parameter of the transistor from standard voltages to lower voltages. This parameter change enables the transistor to function properly in a miniaturized sensor configuration where lower operating voltages are necessary to reduce power consumption and enable smaller form factors while maintaining reliable operation.
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
This solution effectively grounds the reference and sensing terminals when the sensor is off, preventing background current disturbances and enabling operation at lower voltages, thus enhancing the reliability and miniaturization of electrochemical gas sensors.
Implementation Method 1
the first switching element and the second switching element are configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal such that the current generated when the sensing electrode and the target gas react while the electrochemical gas sensor is power OFF flows to the ground voltage terminal and a potential at the reference terminal and the potential at the sensing terminal remain equal
Implementation Method 2
the sensing electrode configured to react with a target gas to generate a current
Data Source
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AI summary
Various embodiments disclose an electronic circuit for an electrochemical gas sensor. The electronic circuit comprises a first switching element electrically coupled to a reference terminal of the electrochemical gas sensor and a ground voltage terminal. Further, the electronic circuit comprises a second switching element electrically coupled to a sensing terminal of the electrochemical gas sensor and the ground voltage terminal. In an instance in which the electrochemical gas sensor is powered OFF, the first switching element and the second switching element are configured to electrically couple the reference terminal and the sensing terminal to the ground voltage terminal such that current generated when the sensing electrode and the target gas react while the electrochemical gas sensor is powered OFF flows to the ground voltage terminal and the potential of the reference terminal and the sensing terminal remain the equal.