Power semiconductors

What is the main purpose of attaching a heat sink to a power device?

  1. ATo increase switching speed
  2. BTo change the direction of current
  3. CTo remove heat generated in the device and keep the junction temperature within its limit
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Answer: C. To remove heat generated in the device and keep the junction temperature within its limit

In power devices, conduction and switching losses become heat. A heat sink lowers the thermal resistance of the path that carries heat to the surrounding air, keeping the semiconductor junction temperature below its maximum rating. Too high a temperature changes characteristics, shortens life or destroys the device.

  • A. A heat sink is not a component for increasing switching speed.
  • B. Current direction is set by the circuit; the heat sink is irrelevant.
  • C. Correct. It removes heat and lowers the junction temperature.
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More Power semiconductors questions

  1. How many switching devices does a typical three-phase inverter for driving a three-phase motor use?
  2. In power circuits and the like, what is the small resistor placed in series in the current path to measure current called?
  3. Why is a switching power supply more efficient than a linear power supply, which operates its transistor linearly?
  4. What is the main advantage of the trench gate structure in power MOSFETs, in which the gate is buried in a groove etched into the silicon?
  5. Which correctly describes the typical division of use between silicon MOSFETs and IGBTs?