Post on 31-Oct-2014
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IGBT Insulated-Gate Bipolar
Transistor
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IGBT: Insulated-Gate Bipolar Transistor
• Combination of BJT and MOSFET– High Input Impedance (MOSFET)– Low On-state Conduction Losses (BJT)
• High Voltage and Current Ratings
• Symbol
V-mos
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IGBT
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IGBT Cross Section
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IGBT equivalent circuit
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• the IGBT consists of a PNP driven by an N-Channel MOSFET in a pseudo-Darlington configuration.
• Base of PNP is driven by MOSFET.
• Darlington sweeps base charge and makes PNP to turn off faster.
• But sadly it prevents PNP from saturation.7
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IGBT Output Characteristics
Follows an SCR characteristic
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IGBT Transfer Characteristic
IGBT switching
ECE 442 Power Electronics 10
Switching Times (td, tr, tf):
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They are defined as follows:
Turn-on delay time: 10% of gate voltage to 10% of collector current
Rise time: 10% to 90% of collector current
Turn-off delay time: 90% of gate voltage to 10% of collector voltage
Fall time: 90% to 10% of collector current.
Current vs. Frequency curve
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