Go Down

Topic: MOSFET for high speed PWM (Read 2363 times) previous topic - next topic

RuggedCircuits

Meh...that's a 1.5 ohm MOSFET. That's pretty high and will get very warm if carrying ~1A of current.

If you're constrained by a particular supplier, let us know what that is and perhaps we can work around this constraint.

--
The DIN Rail Mount kit for Arduino: quickly attach your Arduino to standard DIN rail

daveg360

I guess with such a short pulse, using multiple parallel mosfets (that are available), isn't an option?
If your system involves lethal voltages/life critical/flamable elements - you probably shouldn't need to ask.
The Arduino != PC.

TomS

Darn, I didn't check the resistance you are right.

I am currently living in Germany and will be ordering from voelkner.de in the next few days.
If I could find a driver and mosfet there that would be great.
Unfortunately their assortment isn't too big, so conrad.de might be the alternative.

They both seem to carry a lot of transistors by "International Rectifier" so I'm now trying to find suitable mosfet from them, but no luck so far.

Dave:
I have no idea since I haven't worked with mosfets so far, but wouldn't parallel mosfets actually increase the total gate capacitance and thus be even slower?!

daveg360

I was thinking in terms of charging say 4 in parallel would be quicker than 1 large gate.  Finding suitable mosfets for the job isn't trivial though  :~
In terms of mosfet top trumps - the item that RuggedCircuits posted (STP27N3LH5) is pretty hard to beat....  I'm currently trying to design an utterly indestructible H Bridge (it's taking me forever).  I think I might use a number of those.
If your system involves lethal voltages/life critical/flamable elements - you probably shouldn't need to ask.
The Arduino != PC.

MarkT

Quote
You are right, if you want fast, well-defined pulses you will want a combination of a low gate capacitance MOSFET and high-current MOSFET driver, like a Microchip TC4426A.


Not necessarily, for an amp or so a MOSFET driver chip is sufficient in itself (and much faster) - the MIC4422 for instance will drive several amps and has logic level input.  For a low-duty cycle application this will do without further boosting (not much power dissipation required).
[ I won't respond to messages, use the forum please ]

TomS

That's a very interesting idea Mark, thanks for pointing it out!

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy