Acceleration Sensor Driver Circuit Merging Variable Voltage Generators
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Solution Overview
Problem
Conventional acceleration sensors require multiple variable voltage generators, limiting their size due to the volume occupied by these components, which complicates their miniaturization for applications in vehicles.
Innovation Solution
The acceleration sensor design incorporates a driver circuit that outputs a biased AC voltage with a single variable voltage generator, utilizing a current-voltage converter, operational amplifier, synchronous demodulator, and defect detector to detect acceleration and defects, eliminating the need for multiple variable voltage generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple variable voltage generators are used to detect defects, then defect detection capability is improved, but device size increases
Solution Approach 1:
The patent combines multiple variable voltage generators into a single shared variable voltage generator that can selectively apply voltage to different electrode pairs. This merging approach maintains the defect detection capability by using one voltage generator to simulate acceleration effects on multiple electrode combinations, thereby reducing the overall number of components and sensor size while preserving reliability.
Solution Approach 2:
The single variable voltage generator is designed with multi-functionality to serve multiple purposes: it can selectively generate voltage signals for different electrode pairs (e.g., first and second electrode pairs) to simulate various acceleration conditions. This universal design allows one component to perform what previously required multiple dedicated generators, reducing device volume while maintaining comprehensive defect detection.
2Measurement precision
If multiple variable voltage generators are used for defect detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple variable voltage generators into a single integrated unit that can selectively connect to different electrode pairs through switching circuits. This consolidation reduces the number of independent voltage generation circuits while maintaining the ability to precisely control voltage application to specific electrodes for accurate defect detection through methods such as virtual acceleration.
Solution Approach 2:
The patent introduces dynamic switching capability to the single variable voltage generator, allowing it to dynamically connect to different electrode pairs based on the detection requirements. This dynamic configuration enables the system to adaptively apply voltage to different electrode combinations for comprehensive defect detection, maintaining measurement precision while reducing static circuit complexity.
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 configuration allows for a compact acceleration sensor that can detect defects and acceleration effectively, reducing the sensor's size while maintaining functionality, making it suitable for use in vehicles.
Implementation Method 1
The changes of the distances change a capacitance generated between movable electrode 5A and fixed electrode 4A and a capacitance generated between movable electrode 5B and fixed electrode 4B
Implementation Method 2
Operational amplifier 6 has input port 6A receiving an output of fixed electrode 4A, and input port 6B selectively connected to reference voltage generator 9A and variable voltage generator 10A
Implementation Method 3
a synchronous demodulator for synchronously detecting the voltage output from the first operational amplifier
Data Source
AI summary
An acceleration sensor includes a driver circuit for outputting a biased alternating-current (AC) voltage having a variable bias voltage, a detector element having a capacitance provided between a fixed electrode and a movable electrode changing depending on acceleration applied to the detector element, a current-voltage (C/V) converter for converting a current output from the movable electrode of the detector element into a voltage and outputting the voltage, a first operational amplifier outputting a voltage depending on the input voltage, a synchronous demodulator for synchronously detecting the voltage output from the first operational amplifier, and a defect detector for outputting a defect detection signal when the defect detector determines that the voltage output from the first operational amplifier is out of a predetermined range while the biased AC voltage output from the driver circuit is a predetermined voltage. This acceleration sensor can have a small size.