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Electronics => Electronics => Topic started by: TrickyNekro on January 10, 2009, 06:17:14 AM

Title: MOSFET questions N channel
Post by: TrickyNekro on January 10, 2009, 06:17:14 AM

Hello guys!!!

I want to ask 2 - 3 thingies this time...
Firstly... With a N channel... Is it better to feed the gate through 13V battery, or with 5V regulated...

And secondly...
Since I deal with currents rated at 20A.... When it's better.... When I feed the gate with 13V or 5V???

The power source is at 12.6V ~ 13V... A Lipo battery...

And thirdly... As heatsink.... is unavoidable.... and I cannot unfortunately place more MOSFETs as the place is tight and I don't want to
have problems with the current sensor I'm testing.... Not sure If I have anyways.... whatever...
How can I calc the heatsink dimensions???

I use the IRF540 rated at 175 ^oC max temp.


Thanks in advance!
Lefteris, Greece

Title: Re: MOSFET questions N channel
Post by: want2learn on January 10, 2009, 07:06:24 AM

What transistor are you referring to?

The datasheet should provide info on heatsink calaculations, your'e looking at dissapating quite a bit of power here so the heatsinks going to be a biggee

Title: Re: MOSFET questions N channel
Post by: Admin on January 15, 2009, 08:17:08 AM

Quote

I want to ask 2 - 3 thingies this time...
Firstly... With a N channel... Is it better to feed the gate through 13V battery, or with 5V regulated...

And secondly...
Since I deal with currents rated at 20A.... When it's better.... When I feed the gate with 13V or 5V???

Well, a microcontroller won't be able to give it much more than 5V regulated.

But in terms of efficiency, MOSFETs are more efficient with higher gait voltages. In the datasheet you'll probably see a gait voltage to efficiency curve.