Pressure Sensor Redundancy Circuit for Fault Tolerance
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Solution Overview
Problem
Existing pressure sensors with half bridges often fail to produce an electrical output signal when one or more resistive pressure sensing elements malfunction due to excessive vibration, extreme shock, or operation outside permitted parameters.
Innovation Solution
A pressure sensor design incorporating two or more half bridges, an analog-to-digital converter, a microcontroller, an output generator, and redundancy circuits, where the redundancy circuits include a switch and resistor in series, allowing the microcontroller to determine the switch position and bypass malfunctioned resistive pressure sensing elements, enabling continued operation by using the resistance measurements from functional elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundancy circuits with switches and resistors are added to bypass malfunctioned sensing elements, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring redundancy circuits with switches and resistors that are prepared in advance but remain inactive during normal operation. When a sensing element malfunctions, the microcontroller activates the corresponding redundancy circuit to bypass the failed component, ensuring continuous measurement capability without requiring physical reconfiguration or manual intervention.
Solution Approach 2:
The patent utilizes parameter changes by dynamically altering the electrical state of redundancy circuits based on the operational status of sensing elements. The microcontroller monitors resistance values and, upon detecting a malfunction, changes the state of switches in the redundancy circuits from open to closed, thereby changing the circuit configuration from series to parallel and enabling bypass operation.
2Reliability
If multiple half bridges with redundancy circuits are implemented, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies partial action by implementing redundancy only for specific sensing elements that are prone to malfunction under certain conditions (excessive vibration, extreme shock, or operation outside permitted parameters). Rather than making all sensing elements fully redundant, the system selectively activates redundancy circuits only when and where needed, optimizing the balance between reliability and manufacturing cost.
3Reliability
If the microcontroller continuously monitors all sensing elements to detect malfunctions, then reliability is improved, but use of energy increases
Solution Approach 1:
The patent applies periodic action by having the microcontroller monitor resistance values of sensing elements at discrete intervals rather than continuously. The system periodically reads the resistance values, compares them against expected ranges, and activates redundancy circuits only when malfunctions are detected, thereby reducing power consumption while maintaining adequate fault detection capability for the application.
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
Enables the pressure sensor to produce an electrical output signal corresponding to the fluid pressure even if one or more resistive pressure sensing elements malfunction, ensuring continuous measurement capability.
Implementation Method 1
Each of the two or more half bridges comprise a first resistive pressure sensing element (RPSE) and a second RPSE, such that the resistance of the first RPSE increases when the pressure of the fluid increases, and the resistance of the second RPSE decreases when the pressure of the fluid increases
Data Source
AI summary
A pressure sensor is claimed for measuring the pressure of a fluid. The pressure sensor comprises two or more half bridges, an analog-to-digital converter, a microcontroller, an output generator, and one or more redundancy circuits. Each half bridge comprises two resistive pressure sensing elements (RSPE) electrically coupled to the analog-to-digital converter. Each redundancy circuit comprises a switch and resistor electrically in series. A redundancy circuit may be disposed electrically in parallel with any or all of the RSPEs of the half bridges such that when an RSPE fails open, its corresponding redundancy circuit may be activated in order to permit the resistor of the redundancy circuit to take the place of the RSPE. This permits the analog-to-digital converter to continue to operate normally, even with a failed RSPE. The pressure sensor may then base its calculated pressure on the remaining half bridges which do not have a failed RSPE.