Clamped Inductive Switching Test for Integrated Power Transistors
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Solution Overview
Problem
Existing transistor testing methods, such as unclamped inductive switching (UIS) and clamped inductive switching (CIS), are unsuitable for high-volume automated testing due to the lack of external access to transistor terminals in integrated power modules and other electronic devices, necessitating manual operations and limiting the scalability of testing.
Innovation Solution
A test system and method utilizing a controller, test inductor, switching circuit, measurement circuit, and clamp circuits to perform clamped inductive switching (CIS) testing on transistors within electronic devices, even when control terminals are not directly connected, by precharging a capacitor and inductor and controlling the flow of test current to measure transistor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If dedicated bench equipment is used for UIS or CIS transistor testing, then testing can be performed on transistors, but manual operations are required and automation is unsuitable for large sample sizes
Solution Approach 1:
A test system with automated test equipment (ATE) is introduced as an intermediary between the operator and the transistor device under test (DUT). The ATE includes a controller that automatically controls switching circuits, precharge circuits, and measurement circuits to perform CIS testing without manual intervention. The system provides automated connections to transistor terminals through device leads, enabling high-volume automated testing while maintaining the ability to test integrated transistors with internal control terminals.
2Productivity
If high-volume automated test equipment is used for testing dedicated transistor devices, then large sample sizes can be tested, but testing is difficult when device design does not provide external access to transistor terminals
Solution Approach 1:
The test system is designed with universal adaptability to test both dedicated transistor devices and integrated power modules through different connection configurations. The ATE can automatically connect to externally accessible transistor terminals via device leads, and also test integrated transistors by connecting to device leads while the control terminal remains internally connected. The controller automatically manages the testing process for various device types, enabling high-volume testing across multiple device architectures.
Solution Approach 2:
Device leads serve as intermediaries that provide automated access to transistor terminals in both dedicated and integrated devices. For integrated power modules, the device leads connect to the transistor terminals while the control terminal remains internally connected through the device's own control circuitry. This intermediary approach enables automated testing without requiring physical modification to the device design.
3Device complexity
If transistor control terminals are internally connected without external access, then device integration is improved, but automated testing becomes difficult
Solution Approach 1:
The testing function is extracted from the device itself and implemented as a separate automated test system. The ATE externally provides the necessary test signals and measurements through device leads, while the device's internal control terminal connections remain intact. This extraction allows automated testing without requiring the control terminal to be externally accessible, preserving the device's integrated design while enabling automated testing capability.
Solution Approach 2:
The test system acts as an external intermediary that interfaces with the device through available device leads. For integrated transistors where the control terminal is not externally accessible, the test system connects to other device terminals and uses the device's internal control circuitry to operate the transistor. This intermediary approach enables automated testing while maintaining the benefits of internal control terminal integration.
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
Enables high-volume automated testing of integrated transistors with internal control terminals, ensuring reliability and performance evaluation while protecting transistors from overvoltage conditions, thereby reducing testing time and costs.
Implementation Method 1
a test inductor having a first inductor terminal, and a second inductor terminal coupled to a supply
Implementation Method 2
a test capacitor adapted to be connected to the first device terminal
Implementation Method 3
a clamp circuit connected between the first transistor terminal and the control terminal
Data Source
AI summary
An electronic device includes a transistor having first and second transistor terminals and a control terminal, a control circuit connected to the control terminal, a first device terminal connected to the first transistor terminal, a second device terminal connected to the second transistor terminal, and a clamp circuit connected between the first transistor terminal and the control terminal. A test method includes connecting a capacitor to the first device terminal, connecting an output circuit to the second device terminal, precharging the capacitor, disconnecting a precharge circuit from the capacitor, precharging an inductor, connecting the inductor to the first device terminal while the precharge circuit is disconnected, and testing the transistor while a test current is flowing.