Test Apparatus Using Inductance for Voltage Gradient Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High withstand voltage semiconductor devices pose a challenge in detecting defects related to the gradient of rising power supply voltage, as existing test apparatuses find it difficult to control and manage the high power supply voltage effectively.
Innovation Solution
A test apparatus and method utilizing a field effect transistor and inductance in series with the device under test, controlled by a gate voltage to gradually change the power supply voltage, allowing for defect detection based on power supply current changes, with a reference voltage supply and judgment section to assess the device's quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high power supply voltage is supplied to the device under test, then the device can be tested for high withstand voltage characteristics, but it becomes difficult to control the gradient of the rising power supply voltage
Solution Approach 1:
The patent introduces an inductance as an intermediary element between the power supply and the device under test. This inductance acts as a mediator that naturally limits and controls the rate of change of voltage (dv/dt) during power supply transitions, enabling precise control of the voltage gradient without requiring complex control circuitry. The inductance value is selected based on the desired gradient characteristics, making the system both controllable and reproducible.
Solution Approach 2:
The patent changes the electrical parameters of the power supply system by introducing an inductance with a specific inductance value. This parameter change transforms the power supply characteristics, enabling controlled voltage gradient generation. The inductance value is carefully selected to achieve the desired gradient effect while maintaining compatibility with high voltage testing requirements.
2Measurement precision
If the gradient of the rising power supply voltage is increased to detect defects, then defect detection capability is improved, but it becomes harder to manage the high power supply voltage in the test apparatus
Solution Approach 1:
The inductance serves as a passive intermediary that automatically generates the desired voltage gradient without requiring active control mechanisms. This simplifies the test apparatus by eliminating complex control circuits while still achieving the necessary gradient for defect detection. The gradient is determined solely by the inductance value and the power supply current change rate.
Solution Approach 2:
The inductance element provides self-regulating voltage gradient control based on the inherent relationship between inductance, current change rate, and voltage (V = L di/dt). The system automatically generates the required gradient without external intervention or complex control logic, reducing the management burden on the test apparatus while maintaining high measurement precision.
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 reliable detection of defects attributed to power supply voltage gradients with high reproducibility, preventing defects from going undetected and reducing the burden on the test apparatus by managing high voltage applications effectively.
Implementation Method 1
an inductance that is connected between the positive side terminal and the negative side terminal of the reference voltage supply section
Implementation Method 2
a field effect transistor provided between a positive side terminal and a negative side terminal of the reference voltage supply section, so that a drain terminal and a source terminal of the field effect transistor are in parallel connection with the device under test
Data Source
AI summary
Change in power supply voltage supplied to a device under test is controlled. There is provided a test apparatus for testing a device under test, the test apparatus including: a reference voltage supply section for supplying a reference voltage; a field effect transistor provided between a positive side terminal and a negative side terminal of the reference voltage supply section, so that a drain terminal and a source terminal of the field effect transistor are in parallel connection with the device under test; an inductance that is connected between the positive side terminal and the negative side terminal of the reference voltage supply section, the inductance being in serial connection with the device under test between a positive-side power supply terminal and a negative-side power supply terminal of the device under test, and being in serial connection with the field effect transistor between the drain terminal and the source terminal of the field effect transistor; a control section for controlling a gate voltage of the field effect transistor, thereby changing a power supply voltage to be supplied to the device under test; and a judgment section for judging quality of the device under test, based on characteristic of the device under test in accordance with change in the power supply voltage.