Pressure Sensor Power Management via Piezoelectric Triggering
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Solution Overview
Problem
Existing pressure sensors face challenges in reducing power consumption while maintaining the ability to detect momentary pressure abnormalities, particularly when power supply is intermittent.
Innovation Solution
A pressure sensor design incorporating a membrane with a piezoelectric body and a changeover unit that switches power supply based on detection signals from the piezoelectric body, allowing for reduced power consumption and preventing detection omission of pressure changes by using a bridge circuit with strategically arranged resistors and piezoelectric portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electric power is intermittently supplied to the pressure sensor by pulse driving, then power consumption is reduced, but momentary pressure abnormalities occurring when power is turned off cannot be detected
Solution Approach 1:
The detection function is segmented into two parts: the piezoelectric body continuously monitors pressure changes without requiring power supply, while the resistor bridge circuit is activated only when needed for precise measurement. This segmentation allows the system to maintain detection reliability while reducing power consumption during normal operation.
Solution Approach 2:
The piezoelectric body acts as an intermediary that continuously detects pressure changes and triggers the resistor bridge circuit only when necessary. This intermediary mechanism ensures that momentary pressure abnormalities are captured and transmitted to the main detection circuit, preventing detection omissions while maintaining low power consumption state during normal operation.
2Measurement precision
If the piezoelectric body is disposed on the membrane for continuous monitoring, then detection accuracy is improved, but power consumption increases
Solution Approach 1:
The detection system is divided into a continuous monitoring component (piezoelectric body) and an intermittent measurement component (resistor bridge circuit). The piezoelectric body maintains detection accuracy by continuously monitoring pressure changes, while the resistor bridge circuit is activated only when precise measurement is needed, thereby reducing overall power consumption.
Solution Approach 2:
Different parts of the detection system have different operational characteristics: the piezoelectric body operates continuously with high sensitivity for monitoring, while the resistor bridge circuit operates intermittently for precise measurement. This local quality differentiation optimizes both detection accuracy and power consumption by assigning different functional roles to different components.
3Measurement precision
If resistors are arranged in a bridge circuit for precise pressure detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The resistor bridge circuit operates periodically rather than continuously, being activated only when the piezoelectric body detects significant pressure changes. This periodic operation maintains measurement precision when needed while reducing the effective complexity of the system by minimizing the time the complex circuit is active and requiring full operational readiness.
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
This design effectively reduces power consumption and prevents detection omission of pressure changes by utilizing the piezoelectric body to accurately control power supply, enhancing detection accuracy and miniaturization.
Implementation Method 1
the piezoelectric body generates a piezoelectric effect due to a deformation of the membrane
Implementation Method 2
a pressure sensor that detects a distortion of a membrane (also referred to as a diaphragm) by resistance change using a piezoresistive effect
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
To provide a pressure sensor that makes it possible to reduce power consumption and prevent pressure variation detection failure. [Solution] A pressure sensor comprising: a membrane that deforms in response to pressure; a pressure detection circuit that includes at least four resistive elements disposed on the membrane, the resistive elements forming a bridge circuit to detect deformation of the membrane; a piezoelectric element that is disposed on the membrane and that detects deformation of the membrane; and a switching unit that switches power supply to the pressure detection circuit on the basis of a detection signal from the piezoelectric element.