Insulated Gate Bipolar Transistors

Discrete Semiconductor Devices and Circuits

  • Question 1

    What is an Insulated Gate Bipolar Transistor (IGBT), and what advantages does the IGBT provide over both power MOSFET and traditional BJT devices?

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  • Question 2

    Complete the schematic diagram showing an equivalent circuit for an N-channel IGBT, using an N-channel E-type MOSFET and a PNP bipolar transistor:



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  • Question 3

    The equivalent circuit for an IGBT - comprised of a MOSFET coupled to a BJT - bears resemblance to a couple of other BJT circuits you may have seen before:



    Which of these two paired-BJT circuits most resembles the IGBT equivalent circuit, in terms of what two terminals the control signal voltage must be applied between to turn the device on?

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  • Question 4

    Draw a complete schematic diagram showing how this IGBT can be used to control a DC motor, at the command of the toggle switch:



    Note: the DC power supply voltage is 240 VDC, and the IGBT’s maximum gate-to-emitter control voltage is 20 volts!

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  • Question 5

    Examine the schematic diagram for this photographic strobe light control system:



    Explain its operation, and explain why an IGBT is a good transistor type for this application.

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