Pressure Sensor Self-Diagnostics via Parasitic Diode Monitoring
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Solution Overview
Problem
Existing pressure measuring devices lack a reliable method to verify the uninterrupted contact of the measuring element, leading to potential faults and operational uncertainties.
Innovation Solution
A method utilizing a parasitic diode path in the semiconductor substrate of the pressure measuring device, combined with a switch unit and microcontroller, to switch between pressure measurement and diagnostic modes, allowing for precise identification of electrical line interruptions by measuring forward voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a redundant structure using a second measuring element or additional LED is provided to detect interruption in electrical lines, then the reliability of fault detection is improved, but the device complexity increases
Solution Approach 1:
The measuring element uses its own parasitic diode path for self-diagnosis of electrical line interruptions. The microcontroller measures the forward voltage drop across the parasitic diode formed between the p-conducting and n-conducting layers of the semiconductor substrate, allowing the device to monitor its own electrical connections without external test equipment or redundant structures.
Solution Approach 2:
The invention extracts and utilizes the parasitic diode path that inherently exists in the semiconductor substrate between the p-conducting and n-conducting layers. This parasitic structure, which would normally be considered an unwanted byproduct, is repurposed as a diagnostic tool to detect electrical line interruptions by measuring its forward voltage drop.
2Reliability
If complex redundant structures are used to verify uninterrupted contact of the measuring element, then the reliability is improved, but the manufacturing cost and device complexity increase
Solution Approach 1:
The measuring element performs self-verification of its electrical connections by utilizing the parasitic diode path within its own semiconductor substrate. The microcontroller measures the forward voltage drop across this parasitic diode to determine whether electrical lines are intact, enabling the device to monitor its own health without external assistance or redundant components.
Solution Approach 2:
The invention converts the parasitic diode path, which is typically considered an unwanted side effect of the semiconductor fabrication process, into a useful diagnostic feature. By measuring the forward voltage drop across this parasitic structure, the system transforms a potential source of error into a reliable indicator of electrical connection integrity.
3Reliability
If the switch unit switches between pressure measurement mode and diagnostic mode, then the fault diagnosis capability is improved, but the measurement time is increased due to mode switching
Solution Approach 1:
The microcontroller periodically switches between pressure measurement mode and diagnostic mode to monitor the health of electrical connections. During normal operation, pressure measurements are taken; at scheduled intervals, the switch unit redirects the measurement signal through the parasitic diode path to check for electrical line interruptions, ensuring continuous reliability monitoring with minimal interruption to primary function.
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 efficient and precise fault diagnosis of electrical connections, reducing downtime and improving operational reliability by accurately identifying and localizing faults without complex redundant structures.
Implementation Method 1
Between the p- and n-type dopings, the semiconductor substrate has a parasitic diode path (body diode) that is not used for pressure measurement
Implementation Method 2
a microcontroller detects a forward voltage between the n-conducting and p-conducting layers by being connected to at least one of the four electrical lines at a point P and measuring, in diagnostic mode, the voltage drop between this point P and the further connection pad
Implementation Method 3
a measuring bridge with at least one piezoresistive resistance track. The semiconductor substrate has an n-conducting layer and a p-conducting layer
Data Source
AI summary
A method monitors the function of a pressure measuring device with a measuring element composed of a semiconductor substrate and a measuring bridge consisting of at least one piezoresistive resistance track. The semiconductor substrate has an n-conducting layer and a p-conducting layer and four first connection pads are connected to the p-conducting layer for electrically contacting the measuring bridge.At least one of the four electrical lines is connected to a switch unit to switch between a pressure measurement mode and a diagnostic mode, and the semiconductor substrate has a further connection pad connected to the n-conducting layer. A microcontroller detects a forward voltage between the n-conducting and p-conducting layers by being connected to at least one of the four electrical lines at a point P and measuring, in diagnostic mode, the voltage drop between this point P and the further connection pad.A pressure measuring device performs function monitoring.