Industrial electronics
Why?
Why H-bridges need dead time
Why must both switches in an inverter leg wait before switching?
Quick check · tap an answer to continue
Lesson notes
Key points
- Because each inverter leg has two switches stacked directly across the DC supply, upper and lower.
- Because real MOSFETs and IGBTs take time to turn off, one switch can still conduct as the other turns on.
- Because both on together short the supply, a huge shoot-through current flows and can destroy the devices.
Definitions
- Shoot-through
- Both switches in one leg conduct at once, shorting the DC bus through the devices.
Takeaway: So a short both-off gap, dead time, protects the leg.
Quick check: What fault does dead time in an inverter leg prevent?
- Shoot-through
- Thermal runaway
- Reverse recovery
Dead time keeps both switches off briefly so they never short the supply.
Inverter legTurn-off delayShoot-through
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