Switching Device Turn-Off Test Apparatus with Variable Resistor
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Solution Overview
Problem
Existing turn-off switching tests for switching devices often apply excessive stress, leading to high breakage rates due to variability in measurement environments and devices.
Innovation Solution
A testing apparatus and method that includes a variable resistor coupled to the control electrode of a switching device, a storage circuit for voltage change rate information, and a control circuit to adjust the resistance value and pulse width, ensuring that the switching device is tested under conditions that minimize excessive stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stricter conditions (excessive stress) are set for turn-off switching test, then the test can screen out detective products, but the breakage rate of switching devices increases
Solution Approach 1:
The patent applies dynamics by making the resistance value adjustable during the test process. The control circuit changes the resistance value from a first value to a second value based on the measured voltage change rate, allowing the test conditions to adapt dynamically rather than being fixed. This resolves the contradiction by enabling the system to start with stricter conditions for detection and then relax conditions based on real-time feedback.
Solution Approach 2:
The patent implements feedback by measuring the voltage change rate during the test and using this information to adjust the resistance value. The control circuit compares the measured voltage change rate with reference values and modifies the resistance accordingly. This feedback mechanism allows the system to screen detective products effectively while preventing excessive stress that would cause breakage.
Solution Approach 3:
The patent changes the resistance parameter during the test process based on the measured voltage change rate. By adjusting the resistance value from a first value to a second value, the system modifies the stress conditions applied to the switching device. This parameter change enables the system to achieve both detection capability and reduced breakage rate.
2Manufacturing precision
If stricter conditions are set for turn-off switching test, then the performance requirement can be ensured, but excessive stress damages the switching device
Solution Approach 1:
The system dynamically adjusts the resistance value based on real-time voltage change rate measurements. This allows the test to ensure performance compliance through initial stricter conditions while adapting to protect device integrity based on actual device response during testing.
Solution Approach 2:
The resistance parameter is changed during the test process based on measured performance metrics. This parameter adjustment ensures that performance requirements are met while preventing excessive stress that would compromise device integrity.
3Ease of operation
If fixed resistance value is used in turn-off switching test, then the test process is simple, but the test accuracy decreases due to variability in measurement environments
Solution Approach 1:
The patent transitions from a fixed resistance value approach to a dynamic adjustment approach. The control circuit automatically adjusts the resistance value based on measured voltage change rates, maintaining test process simplicity while significantly improving measurement precision by compensating for environmental variability.
Solution Approach 2:
The system uses feedback from voltage change rate measurements to adjust the resistance value, improving test accuracy without significantly complicating the test process. The automatic adjustment based on real-time measurements compensates for environmental variability while maintaining operational simplicity.
Data Source
AI summary
A testing apparatus, including: a variable resistor coupled to a control electrode of a switching device; a storage circuit storing information indicating a relation between a resistance value of the variable resistor and a voltage change rate at which a voltage between power-source-side and ground-side electrodes of the switching device changes when the switching device is turned off; and a control circuit controlling the variable resistor. The control circuit sets the variable resistor to have a first resistance value and obtains a first value of the voltage change rate, sets the variable resistor to have a second resistance value based on the first value of the voltage change rate and the information, obtains a second value of the voltage change rate when the variable resistor is of the second resistance value, and determines whether the second value of the voltage change rate meets a specification of the switching device.