Paralleled P channel MOSFETs to switch 30 Amp 12V circuit

Thread Starter

Chipper

Joined Jul 19, 2018
43
I've been working a few ideas to improve the wiring in my home built camper. I want to replace an automotive type relay with a MOSFET (Infineon IPP120P04P4L03AKSAI0) 3 parallel circuit. I have come up with this design, but it seems almost too easy. any expert advice would be appreciated! When researching this circuit I found concerns about oscillations induced by gate voltage variations
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Thread Starter

Chipper

Joined Jul 19, 2018
43
good to hear from you again crutschow, i want the circuit output to on when the gate is closed or low, forgot the dots on the gate leads and the drain leads are not used, as i would use the heatsink mounts as conductors
 

crutschow

Joined Mar 14, 2008
24,410
I changed my post because I was incorrect about the switch operation.
It is indeed on when the switch is closed.

I would reduce the 100k resistor to 10k.
 

Thread Starter

Chipper

Joined Jul 19, 2018
43
Can’t you eliminate the parallel MOSFETs with one 60A p-channel MOSFET?
That's a great question, I'm connecting to 10 gauge wiring and the leads on these MOSFETs look so small that I'm concerned about heat build up at full load. changed my original post to reflect the proper connections
 
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OBW0549

Joined Mar 2, 2015
3,221
Found this, which may be the same device electrically.
Sure looks like it-- and I see from the datasheet that it's rated at 120 amps and an Rds(on) of 3.1 milliohms. Which raises the question, why in the world the TS thinks he needs to parallel three of them?

I'm connecting to 10 gauge wiring and the leads on these MOSFETs look so small that I'm concerned about heat build up at full load.
If the device is rated at 120 amps, it's good for 120 amps no matter what you think if the lead size. With an Rds(on) of 3.1 milliohms and passing 30 amps, it will be dissipating about 3 watts which means you can get by with a modest-size heatsink. And I REALLY don't think you need to parallel three of these things.
 

Thread Starter

Chipper

Joined Jul 19, 2018
43
Yes, I noticed. And the question wasn't answered, so I repeated it for emphasis.
Sorry to leave all hanging on this, as I had to attend to some family business. My thinking on this is strictly on the problems of attaching a 10 ga stranded lead to the MOSFETs. 105 strands at .010" ea. makes for a challenge. I have elected to divide to 10 ga. conductor into 3 separate bundles and solder them to the MOSFET pins. The MOSFET sells for approx. $2.50 ea. If had a lot of these to make I'd have to work something out with a PCB. Hope that explains it ;)
 

be80be

Joined Jul 5, 2008
2,011
Just use one of these and one Mosfet you can cut it down for 3 terminals


It's rated for 30 amps they come bigger it needed
10 awg in one side Mosfet on the top done deal and if something needs changing it easy to fix.
 

Thread Starter

Chipper

Joined Jul 19, 2018
43
Just use one of these and one Mosfet you can cut it down for 3 terminals


It's rated for 30 amps they come bigger it needed
10 awg in one side Mosfet on the top done deal and if something needs changing it easy to fix.
thanks, be80be, what is this called? do you have a part number?
 
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