Test Apparatus Semiconductor Switch Diverts Avalanche Current
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Solution Overview
Problem
Existing test apparatuses for large-current switching devices face challenges in preventing excessive current flow during avalanche breakdown tests, which can damage both the device under test and the apparatus, making it difficult to analyze malfunctions and requiring quick intervention to prevent damage.
Innovation Solution
A test apparatus with a power supply section, an inductive load section, a first semiconductor switch connected in parallel with the device under test, and a control section that turns the switch ON when power supply is stopped to divert excessive current, along with additional semiconductor switches and an abnormality detecting section to manage voltage and current effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the device under test is switched to a non-conductive state during avalanche breakdown test, then electrical energy accumulates in the inductive load, but excessive current flows through the device when voltage exceeds rated value causing damage
Solution Approach 1:
A first semiconductor switch is introduced as an intermediary component connected in parallel with the device under test. This switch acts as a protective mediator that diverts excessive current away from the device under test when avalanche breakdown occurs, preventing damage while allowing the avalanche test to proceed
Solution Approach 2:
The first semiconductor switch is configured to be turned ON in advance when power supply voltage is stopped, before excessive current can flow through the device under test. This preliminary action ensures the protective path is ready to capture and divert the avalanche current from the inductive load
2Reliability
If a switch is used to prevent excessive current flow when device malfunctions, then device and apparatus are protected from damage, but the response time must be extremely fast to prevent current flow during avalanche period
Solution Approach 1:
A control section monitors the operational state of the device under test and provides feedback control for the first semiconductor switch. When the device malfunctions or power supply is stopped, the control section immediately activates the protective switch, ensuring rapid response without requiring the protective switch to operate faster than the device itself
Solution Approach 2:
The protective switch configuration allows the system to self-protect through automatic activation controlled by the control section, eliminating the need for manual intervention and ensuring the protective action occurs as quickly as the control system can respond
3Power
If multiple IGBT elements are arranged in parallel according to current specifications, then the device can handle large current, but excessive current during malfunction can spread damage across multiple elements making analysis difficult
Solution Approach 1:
The first semiconductor switch extracts and diverts the harmful avalanche current away from the parallel IGBT elements. By taking the excessive current out of the device circuit and routing it through the protective switch, the original device structure remains intact and can be analyzed without widespread damage
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
Prevents excessive current from flowing through the device under test, thereby protecting it and the test apparatus from damage, allowing for accurate analysis of malfunctions and safe operation during avalanche breakdown tests.
Implementation Method 1
the device under test is connected to an inductive load, such as an inductor, and electrical energy is accumulated in the inductive load while the device under test is in a conductive state
Implementation Method 2
the current from the inductive load be quickly prevented from flowing through the device under test by using a switch, for example
Data Source
AI summary
To prevent an excessive current from flowing through a device under test. A test apparatus that tests a device under test, comprising a power supply section that generates a power supply voltage to be supplied to the device under test; an inductive load section that is provided in a path leading from the power supply section to the device under test; a first semiconductor switch that is provided in the path leading from the inductive load section to the device under test and is connected in parallel with the device under test; and a control section that turns the first semiconductor switch ON when supply of the power supply voltage to the device under test is stopped.