I am designing a H-Bridge using IRLZ44N MOSFETs, IR2104 driver ICs and UF5401 diodes.
The current circuit looks like this:
It will be used on a battery powered device, so no real grounding available, the casing will be plastic or close to nothing.
The only place a human could touch is the motor terminals and the power connector.
I have read in many questions that proper ESD protection is very important and such components are very sensitive, but even so I am confused as most H-bridge tutorials don't include anything about being ESD-safe.
TL;DR: Do I need additional protection for the average use case with these components?
Best Answer
The MOSFETs aren't sensitive to ESD on the source and drain. If you zap the bridge output the transistors will take the hit: the drain to source capacitance will limit the transient rise time, and they are rated for an avalanche breakdown energy of several hundred millijoules at room temperature. The gate of the transistors is susceptible to ESD but it isn't an exposed connection. I would be more worried about the optocoupler LEDs being zapped, but even they are fairly rugged. If the power supply input is zapped the input filtering caps will bypass most of the pulse.