Variable Reference Voltage AGC for Sensor Burn-in Testing
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Solution Overview
Problem
Current physical quantity sensors, such as gyro sensors, face challenges in efficiently conducting burn-in tests due to the difficulty in changing the drive level of sensor elements, leading to prolonged test times and increased costs, especially when auto gain control (AGC) circuits are involved.
Innovation Solution
A physical quantity sensor design that incorporates a variable reference voltage for the AGC circuit, allowing for the selection and application of different voltage signals to overdrive the sensor element during burn-in tests, thereby reducing test time and enabling optimal testing across various sensor types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a higher power supply voltage than usual is applied to overdrive the sensor element, then the burn-in test time can be reduced, but the AGC circuit prevents the drive level from changing because it maintains constant output sensitivity
Solution Approach 1:
The patent changes the reference voltage parameter of the AGC circuit to enable drive level adjustment. By making the reference voltage variable instead of fixed, the system can temporarily increase the drive level during burn-in tests while maintaining constant output sensitivity during normal operation, thus resolving the contradiction between test time reduction and drive level adaptability
2Reliability
If the drive level is increased during burn-in test, then sensor element reliability can be evaluated more quickly, but additional circuits or complex control mechanisms are required
Solution Approach 1:
The reference voltage circuit serves multiple functions: it provides the reference voltage for the AGC circuit during normal operation and enables drive level adjustment during burn-in tests. This multi-functionality allows reliability evaluation without requiring separate dedicated circuits, thus improving reliability assessment capability while minimizing additional 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 approach allows for a significant reduction in burn-in test time, enhances the reliability of physical quantity sensors, and enables cost-effective evaluation of sensor elements by allowing for optimal overdriving based on their properties.
Implementation Method 1
a gyro sensor using a piezoelectric vibrator
Data Source
AI summary
A physical quantity sensor includes: a sensor element which detects predetermined physical quantity; a driving circuit which generates a driving signal of the sensor element; and an AGC circuit which controls the driving signal at a constant level according to a reference voltage, based on an output signal of the sensor element, in which the reference voltage is variable.