Power semiconductors

Which correctly describes the typical division of use between silicon MOSFETs and IGBTs?

  1. AMOSFETs suit fast switching at relatively low voltages, while IGBTs suit high voltages of several hundred volts or more and large currents
  2. BIGBTs suit low voltage and small current, while MOSFETs suit high voltage and large current
  3. CBoth can only be used for the same applications
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Answer: A. MOSFETs suit fast switching at relatively low voltages, while IGBTs suit high voltages of several hundred volts or more and large currents

Silicon MOSFETs operate with majority carriers only, so they switch fast, but their on-resistance rises sharply at high breakdown voltages. IGBTs use conductivity modulation by injected minority carriers to keep the on-state voltage low even at high voltages, suiting large-current applications of several hundred volts and above. In exchange, their tail current makes them slower to switch.

  • A. Correct. MOSFETs suit fast, low-to-medium voltage use; IGBTs suit high voltage and current.
  • B. The applications are reversed.
  • C. They are chosen according to voltage and frequency.
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More Power semiconductors questions

  1. What is the main purpose of a snubber circuit in a power device switching circuit?
  2. When one switch of an inverter turns on, which loss increases due to the reverse recovery of the diode in the opposite arm?
  3. Among soft-switching techniques for power converters, which correctly describes ZVS (zero-voltage switching)?
  4. When a power MOSFET's gate is charged with a constant current, why does the gate voltage stay flat for a while (the Miller plateau)?
  5. Why is a negative gate voltage (for example, −3 to −5 V) sometimes applied to SiC MOSFETs or IGBTs in the off state?