magnet control through PIC

[SterlingY]

Thanks for all of the info so far.

Can someone suggest a logic-level MOSFET that they might use for this type of project?

Thanks,

Sterling

[skimask]

Thanks for all of the info so far.

Can someone suggest a logic-level MOSFET that they might use for this type of project?

Thanks,

Sterling

Unless somebody else beats me to it, I'll get you a good number when I get home after work. I use a few of them, 1 logic level, a couple not so logic level (but work at 5v anyways), and a couple that need a lot of V to turn them on.

Take the advice of the post below. I forgot you were working with electro-magnet type things.

[Acetronics2]

Hi,

Why not look at the automotives protected IGBTs ???

IRGS 14C40 ( I R ) or ISL9V5036 ( Fairchild ) ... MGP 15N40 ( Motorola ... ON Semi. )

No switching issues then !!!

Alain

[SterlingY]

Not sure about the 14C40, but the ISL9V5036, costs almost $4, so 56 of them would be too costly. The Motorola is $2.50, still too much. I'm trying to make this thing for $50-$70.

It may not be possible.

-Sterling

[peterdeco1]

The best MOSFET I've used and use exclusively is an N-channel IRLZ44N. It has .02 ohm ON resistance with a logic level gate drive. It's rated (I think) 44 AMPS in a TO-220 package. We use a pair of them as a replacement for a solid state relay and run them at 1 AMP continuously. They stay cool up to a couple of AMPs without a heatsink, and are bi-directional. If you reverse the load voltage from source to drain they still conduct. If you want, I'll throw a few in an envelope & mail them to you. We have a lot of them.

[SterlingY]

Peterdeco1,

That's a very nice offer, but I can just order a few if I go that route. They are certainly cheaper than the other MOSFETS suggested.

Honetsly, I am beginning to think that MOSFETS may not be the way to go.

It may be determined by the magnets themselves. I've built a few, and now I've got some feelers out there to see what the pros think. I have seen small magnets driven by 6V that can hold 100lbs!!! I only need 1-2lbs. What I am getting at is that I should probably learn what my magnets will require and let that determine what the drivers need to be.

In the mean time, I'm still interested in playing with a multiport analog system and MOSFETS.

-Sterling

[mackrackit]

Another thing to look at is the switching speed. IGBTs normally will switch faster.

I use the FGA40N60UFDTU for motor control DC at 180 volts. These are out of you price range but... http://www.fairchildsemi.com/ds/FG%2FFGA40N60UFD.pdf

Also, the higher the voltage the less amps. (stating the obvious) So try to make a coil that will handle say 48 volts and then you might get by with a MOSFET if the switching speed is not to high.

Either way, do not forget a fly-back diode.

[skimask]

Peterdeco1,

That's a very nice offer, but I can just order a few if I go that route. They are certainly cheaper than the other MOSFETS suggested.

Honetsly, I am beginning to think that MOSFETS may not be the way to go.

It may be determined by the magnets themselves. I've built a few, and now I've got some feelers out there to see what the pros think. I have seen small magnets driven by 6V that can hold 100lbs!!! I only need 1-2lbs. What I am getting at is that I should probably learn what my magnets will require and let that determine what the drivers need to be.

In the mean time, I'm still interested in playing with a multiport analog system and MOSFETS.

-Sterling

Heck, try it out with the MOSFETs and the LEDs like I suggested above...get the firmware working right...swap in the magnets and the flyback diodes, and try it out.
As long as you've got the firmware working, if you accidentally smoke the PIC of a couple of MOSFETs, no biggie, at least the firmware is tested and works. Just have to work out the kinks at the business end...
and of course...I've just overstated the blatantly obvious...

[SterlingY]

Skimask,

You said you built a similar thing with LEDs. Would you happen to have the schematic?

-Sterling