Q4Power Electronics
Question
2 marks
What is a Snubber circuit?
Answer
A snubber circuit is an RC or RCD network connected across (or in series with) a power device to limit dv/dt or di/dt during switching, protecting the device from stress and reducing EMI.
- Turn-off snubber (across device): An RC or RCD circuit that limits the rate of rise of voltage dv/dt across the device during turn-off. Prevents false triggering due to displacement current and reduces switching stress.
- Turn-on snubber (series with device): A series inductor limits di/dt through the device during turn-on, preventing current crowding and hot-spot formation.
- Overvoltage suppression: Absorbs energy stored in stray/parasitic inductances (L·di/dt spikes) that would otherwise appear as voltage spikes across the device.
- Reduces electromagnetic interference (EMI) generated during fast switching transitions.