Power semiconductors

What is the main purpose of a snubber circuit in a power device switching circuit?

  1. ATo lower the device's on-resistance
  2. BTo suppress voltage spikes (surges) and ringing that occur during switching
  3. CTo raise the switching frequency
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Answer: B. To suppress voltage spikes (surges) and ringing that occur during switching

Fast switching causes voltage spikes and oscillation (ringing) due to parasitic inductance in the wiring and the like. A snubber circuit uses capacitors, resistors, diodes and so on to absorb this energy, protecting the device from overvoltage and reducing noise.

  • A. On-resistance is a device property and is not lowered by a snubber.
  • B. Correct. It suppresses surges and ringing.
  • C. A snubber is not meant to raise the switching frequency.
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More Power semiconductors questions

  1. When one switch of an inverter turns on, which loss increases due to the reverse recovery of the diode in the opposite arm?
  2. Among soft-switching techniques for power converters, which correctly describes ZVS (zero-voltage switching)?
  3. 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)?
  4. Why is a negative gate voltage (for example, −3 to −5 V) sometimes applied to SiC MOSFETs or IGBTs in the off state?
  5. What maximum junction temperature (Tj max) is commonly specified for typical silicon power devices?