Pressure Sensor Ballast Resistive Layer Overload Protection
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Solution Overview
Problem
Conventional pressure sensors are prone to circuit damage due to excessive output current when overloaded, as their resistance decreases significantly with increased pressure, leading to potential system failure.
Innovation Solution
Integration of a ballast resistive layer within the pressure sensor to stabilize the output resistance, preventing excessive current flow by maintaining a minimum resistance even under high pressure conditions, using materials like carbon paste, silver paste, or nanomaterials with specific resistivity ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional pressure sensor without ballast resistive layer is used, then the pressure sensor can detect pressure changes with high sensitivity, but the circuit system may be damaged by excessive output current when overload pressure is applied
Solution Approach 1:
The patent introduces a ballast resistive layer as an intermediary element between the piezoresistive layers and the circuit system. This layer acts as a current-limiting mediator that prevents excessive current from reaching the circuit system during overload conditions, while still allowing accurate pressure detection to occur through the piezoresistive layers.
Solution Approach 2:
The ballast resistive layer is pre-configured in the pressure sensor structure to provide beforehand protection against excessive current. By having this protective element in place before overload occurs, the circuit system is cushioned against potential damage without affecting normal pressure measurement operations.
2Measurement precision
If the piezoresistive layers are made with small resistance material to enhance sensitivity, then the pressure sensor output current increases with pressure, but the resistance becomes very small under overload causing excessive current
Solution Approach 1:
The patent applies different resistance characteristics to different parts of the sensor structure. The piezoresistive layers maintain low resistance for high signal output, while the ballast resistive layer provides high resistance for current limiting. This local differentiation of electrical properties allows simultaneous achievement of high sensitivity and overload protection.
Solution Approach 2:
The pressure sensor employs a composite structure combining piezoresistive material and ballast resistive material with distinctly different electrical properties. This composite approach allows the sensor to leverage the high sensitivity of low-resistance piezoresistive material while the high-resistance ballast material prevents excessive current flow under overload conditions.
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
The pressure sensor with a ballast resistive layer ensures that the output resistance remains above a certain threshold even under overload conditions, preventing circuit damage and allowing safe pressure measurement across a wide range of pressures.
Implementation Method 1
two piezoresistive layers 12 and 129 are disposed on the metal electrodes 11 and 119
Data Source
AI summary
A pressure sensor is provided, wherein a ballast resistive layer is integrated in the pressure sensor so that the resistive output curve for the pressure sensor has saturation characteristics. The pressure sensor shall be prevented from breaking down by a large current that may be caused, when an overload pressure is applied on the pressure sensor, if no ballast resistive layer is added.