igbt basics

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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