Temperature-Compensated Resistance Bridge for Force Measurement
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Solution Overview
Problem
Piezo resistor bridges in MEMS sensors are sensitive to temperature changes, which affect the accuracy of force measurements by introducing temperature-induced variations in the offset voltage, making it difficult to isolate the applied force.
Innovation Solution
Incorporating current sources in parallel with resistance elements in the bridge, controlled by a temperature sensor and a control circuit to adjust and compensate for temperature-induced resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation is implemented using external components, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the temperature compensation function with the existing resistance bridge structure by integrating current sources directly into the bridge circuit. The current sources are positioned in parallel with specific resistors (R1, R2, R3, or R4) to compensate for temperature-induced resistance changes, eliminating the need for separate external compensation circuits while maintaining measurement accuracy.
Solution Approach 2:
The resistance bridge circuit is designed to perform multiple functions: it serves as both the force sensing element and the temperature compensation mechanism. By configuring current sources in parallel with bridge resistors and controlling them through switches, the same circuit structure achieves both force measurement and temperature compensation without requiring additional dedicated components.
2Reliability
If current sources are added to compensate for temperature variations, then reliability is improved, but device complexity increases
Solution Approach 1:
The compensation current sources are integrated within the resistance bridge structure itself, merging the temperature compensation function with the force sensing circuit. This integration approach improves reliability by ensuring temperature compensation is inherently part of the measurement system while avoiding the complexity of adding separate external compensation circuits.
3Manufacturing precision
If temperature compensation circuitry is integrated into the sensor, then manufacturing precision is improved, but ease of manufacture decreases
Solution Approach 1:
The patent combines the temperature compensation functionality with the existing resistance bridge manufacturing process. Current sources are integrated into the bridge circuit during fabrication, allowing offset voltage consistency to be achieved through standard manufacturing processes without requiring additional assembly steps or specialized integration techniques.
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 solution effectively cancels out temperature-induced variations, ensuring the resistance bridge operates more accurately and predictably by maintaining offset voltage as a function of force alone, without requiring precise external components or CMOS integration.
Implementation Method 1
The pressure sensor also comprises a temperature sensor
Implementation Method 2
Temperature coefficient of offset compensation for resistance bridge
Data Source
AI summary
Systems and methods for temperature coefficient of offset compensation for a resistance bridge are disclosed. In one aspect, one or more current sources are added in parallel to resistance elements within a resistance bridge. The current source(s) may be selectively switched on and adjusted by a control circuit based on readings from a temperature sensor. In this fashion, the temperature induced variations in the resistance may be canceled or corrected allowing for better performance of the resistance bridge.