Physical Quantity Detector Abnormality Detection Single Bridge Circuit
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Solution Overview
Problem
Conventional physical quantity detectors require two bridge circuit portions to detect abnormalities, which increases size and cost, and struggle to determine abnormalities in a configuration with a single bridge circuit portion.
Innovation Solution
A physical quantity detector configuration with a single bridge circuit portion, utilizing a temperature characteristic adjustment portion and differential signal processing circuits to generate and compare differential voltage signals, allowing for the detection of abnormalities by comparing the first and second differential voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two bridge circuit portions are used to detect abnormalities, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent creates a virtual copy of the bridge circuit output by generating a simulated differential voltage signal that mimics what the second bridge circuit would produce if it were physically present. This virtual copy allows abnormality detection without requiring a second physical bridge circuit, thus maintaining reliability while reducing device complexity
Solution Approach 2:
The patent introduces a signal processing circuit as an intermediary that generates a simulated differential voltage signal based on the output from the first bridge circuit. This intermediary component enables the system to detect abnormalities in a single bridge circuit by comparing its actual output against a theoretically expected output, avoiding the need for a second physical bridge circuit
2Reliability
If two bridge circuit portions are used, then abnormality detection is enabled, but manufacturing cost increases
Solution Approach 1:
Instead of manufacturing a second physical bridge circuit portion, the patent creates a virtual copy through signal processing that simulates the expected output. This eliminates the need to manufacture additional strain gauges, diaphragms, and associated components, significantly reducing manufacturing costs while maintaining abnormality detection capability
Solution Approach 2:
The patent extracts only the essential function of the second bridge circuit (providing a reference output for comparison) and implements it through signal processing rather than physical hardware. This extraction approach removes the costly manufacturing requirements while preserving the core abnormality detection functionality
3Device complexity
If a single bridge circuit portion is used, then device complexity is reduced, but abnormality detection becomes difficult
Solution Approach 1:
The patent implements a feedback mechanism where the signal processing circuit continuously monitors the output from the single bridge circuit, compares it against a simulated reference signal, and uses this feedback to detect abnormalities. The system feeds back the difference between actual and expected outputs to determine whether the bridge circuit is functioning normally
Solution Approach 2:
The signal processing circuit acts as an intermediary that enables abnormality detection in a single bridge circuit configuration. It generates a simulated differential voltage signal that serves as a reference, allowing the system to detect abnormalities by comparing the actual bridge output against this virtual reference without requiring a second physical bridge circuit
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 detection of abnormalities in the bridge circuit portion despite a single bridge circuit configuration, maintaining constant sensitivity and allowing for the determination of abnormalities based on differential voltage signal comparison.
Implementation Method 1
a first strain gauge, a second strain gauge, a third strain gauge, and a fourth strain gauge each having a resistance value that changes in response to an application of a physical quantity and changes in response to temperature
Implementation Method 2
the temperature characteristic adjustment portion having a resistance value change smaller than a resistance value change of the first strain gauge, the second strain gauge, the third strain gauge, and the fourth strain gauge in response to application of the physical quantity and to the temperature
Data Source
AI summary
A physical quantity detector includes: a bridge circuit portion that includes a bridge circuit including a first, second, third, and fourth strain gauges each having a resistance value that changes in response to an application of a physical quantity and to temperature, the bridge circuit portion outputting, as a first detection signal, a first voltage, and outputting, as a second detection signal, a second voltage; a temperature characteristic adjustment portion that is connected in parallel to the bridge circuit portion, and outputs, as a third detection signal, a third voltage corresponding to the input voltage; a first signal processing circuit portion that receives the first and second detection signals, and outputs a first differential voltage; and a second signal processing circuit portion that receives the second and third detection signals, and outputs a second differential voltage.