mosfet h bridge questiion

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zotdoc
Posts: 177
Joined: Tue Jun 17, 2003 1:01 am
Location: Douglas, Georgia
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mosfet h bridge questiion

Post by zotdoc »

I want to make an H bridge controller for a power wheelchair that someone gave me, and I have some IRFP054N mosfets, which should be more than enough to power the two 24 volt wheelchair motors, which have a peak current of 100 amps according to the spec sheet for the motors. The spec sheet for the IRFP054N says they will handle 290 amps Max. I have reviewed a lot of peoples projects and they mostly are for 12 volt systems. I want to use one of the high side mosfet driver chips that are available, but most seem to have a supply voltage of 4 - 16 volts and an output up to 20 volts. Does anyone make a mosfet high side driver for a 24 volt system ( or somewhere between 24 and 50 volts? It seems like the only other mosfet drivers I can find are rated for 600 volts. If there is nothing in between, can I use the larger mosfet driver chip? Thanks for any help anyone can give me. It seems the more I delve into this, the more confused I become.
zotdoc
Posts: 177
Joined: Tue Jun 17, 2003 1:01 am
Location: Douglas, Georgia
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driver chip

Post by zotdoc »

I found these half bridge drivers that should work, IRS2003. I'll try to let everybody know if they work out.
manie
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Joined: Thu Jan 01, 2009 9:42 am
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IRFP054N power rating

Post by manie »

The IRFP054N Hexfets are actually rated up to 81 Amps continuous drain current BUT ONLY at 25 deg C. This reduces to 57 Amps at 100 deg C. The 290 Amps you mention is only for NON REPETITIVE pulsing at ONLY 2% duty cycle. This will hardly turn on the motors IMO.... However, if you double up with two IRFP054N's in parallel on each leg of the H-bridge they should work just fine. Just provide some good heatsinking. As for switching them on, you only need 4.0V to fully switch them on, you can do this via a npn--->pnp switch, the 24V is connected to the drain and source terminals and has little to do with the gate switching. Just make sure you switch them on fully and heat should not really be a problem. I'm currently switching (PWM) 130 Amps at 12V through 4x IRFZ44N's and they're only rated for 49Amps at 25 deg C. Read the spec sheets, its all there... good luck.
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