resistor and diode for mosfet gate
resistor and diode for mosfet gate
(OP)
Hi All,
Im studying a circuit diagram one of my more senior workmates made when he designed a switched mode power supply.
To drive a H-bridge configuration of 4x n-channel power MOSFETS, he used a HIP4080 full bridge driver.
The thing was, he placed a resistor (13R) between the MOSFET gates and the driving pins (ALO, AHO, etc.) of the bridge driver. Parallel to the resistor is a 'soft-recovery' plastic diode.
I was wondering what was the point of putting the resistor and the diode between the driver and the mosfet? Im guessing its some sort of spike protection? how would this work?
Im studying a circuit diagram one of my more senior workmates made when he designed a switched mode power supply.
To drive a H-bridge configuration of 4x n-channel power MOSFETS, he used a HIP4080 full bridge driver.
The thing was, he placed a resistor (13R) between the MOSFET gates and the driving pins (ALO, AHO, etc.) of the bridge driver. Parallel to the resistor is a 'soft-recovery' plastic diode.
I was wondering what was the point of putting the resistor and the diode between the driver and the mosfet? Im guessing its some sort of spike protection? how would this work?





RE: resistor and diode for mosfet gate
RE: resistor and diode for mosfet gate
A lesson I just learned recently: Slower switching also causes HEAT!!! And the HEAT was destroying FETS in my situation. Remember my post "IRF 460 Failures" sreid? Thanks for helping with that BTW.
Just trying to pass along what I've learned.
Scott
In a hundred years, it isn't going to matter anyway.
RE: resistor and diode for mosfet gate
If both pullup and and pulldown are configured similarly, this would avoid current spikes caused by having pullup and pulldown on at the same time.
TTFN
RE: resistor and diode for mosfet gate
The diode resistor circuit was (is) used with bipolar transistors. The resistor set the base drive current so the transistor was not drven into too hard a saturation. The diode provided a high current path to quickly sweep the base charge to minimize heating from the transistor slowly comming out of saturation.
RE: resistor and diode for mosfet gate