definitive technology bipolar review
The term IGBT stands for insulated gate bipolar transistor. Can be thought of as a transistor with a front-end IC. It has three terminals (or leads) Door label, Collector and emitter. IGBT Some have built in a protection diode. This diode is connected across the collector and emitter terminals. Adding to the voltage protection transient when the MOSFET is switching inductive loads.
When these devices are considered "suspect" is required to validate its performance through a functional test procedure. One of the two methods can be used:
The first test method to validate the status of the protection diodes, and the resistance of the collector and emitter terminals. It is not definitive proof, but found 80% of all defective devices. This is due to the fact that most the IGBT defective or show low resistance short across the collector and emitter terminals when the emphasis is on the device.
For this test requires a DVM (Digital Volt-Meter "). Set the DVM to the position of the diode test, and confirm that the test device as follows:
Connect Principal Network DVM to the terminal of the main drainage and Black to the emitter. Confirming an open circuit condition.
Connect the DVM Principal Network to the emitter and the Black lead to the collection terminal. Confirming an open circuit condition (IGBT without a protection diode). If the voltmeter shows a fall voltage of 0.2 to 0.8 V CC means that the PDA has a built in protection diode. Both of these results are normal test conditions and are used to confirm whether CAP has a protection diode, and if so, whether functional or not.
The second test method will verify the functionality of the IGBT's, the synchronization the device. For this test will require an IC tester. Confirm that the test device as follows:
Connect the analyzer leads IGBT to the gate, collector and emitter terminals. Confirm that the steering LED is not lit.
Press the test button, and confirm that the LED lights driving.
Reverse the collector and emitter leads. Do not press the test button. If the LED lights driving the IC has a built in protection diode. This is a standard test condition for this type of device. If the drive LED does not light then the CAP does not have a built in protection diodes. This is also a test condition normal for this type of device.
Importantly, functional testing of the IGBT should always be performed when the device is outside the circuit. In other words, must be removed from the product and have no other electrical connections in place, other than those described in the test procedure.
David Willcocks is an Electronics professional, and Technical writer. For more information on Automated Test Equipment please visit http://www.imagineATE.com
