MOSFET gate drive sinking and sourcing urrent

Thread Starter

Engineering_Junkie

Joined Sep 9, 2015
41
Hey everyone,

I just want to double check something. I have a resistor and diode in parallel to my MOSFET gate which the gate driver passes current through, it sources 1 amp through the resistor to the MOSFET to turn it on and bypasses the resistor through the diode to turn it off.

My understanding is it will ever sink or source more current the its limit although when one of my friends ran a simulation he obtained a sinking current of 19 amp through he diode when the max sinking current of the driver is 4 amp.

Just want to make sure I' not missing something and the simulation is in fact incorrect?

Thanks in advance for any help.
Image: http://imgur.com/a/21ajm
 

jpanhalt

Joined Jan 18, 2008
11,088
The gate is simply a capacitor. The current it gets is over quite a short period usually. Your gate resistance and current capability of the driver, which can be viewed as in internal series resistance, determine that time. Similarly, the turn off time/current is determined by the series resistance. It will not be higher than what your driver can sink.

John
 

Thread Starter

Engineering_Junkie

Joined Sep 9, 2015
41
The gate is simply a capacitor. The current it gets is over quite a short period usually. Your gate resistance and current capability of the driver, which can be viewed as in internal series resistance, determine that time. Similarly, the turn off time/current is determined by the series resistance. It will not be higher than what your driver can sink.

John
thank you!
 
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