Heat-sink for MOSFET in headlamp controller

Suppose I want to make an Arduino-based headlamp controller for my truck and I would like to locate the circuit in the engine compartment. Is there a good way to enclose the project to protect it from splashes and road dirt, and still heat-sink the MOSFETs? If I heat-sink the MOSFETs inside an enclosure, I'm thinking heat will build up to an undesirable level, so wondering what is the proper way.

  1. You may be able to find a MOSFET with a low enough on-resistance that little heat is generated.

  2. If you use a metal case for the controller the case can be the heatsink. You need to insulate the
    metal tab of the MOSFET with a thermally conducting electrically insulating pad, which are available
    for the purpose.

AOI510, very low Rds.
http://www.digikey.com/product-detail/en/alpha-omega-semiconductor-inc/AOI510/785-1487-1-ND/3603498

Hi,
To minimise current losses you could mount the MOSFET close to the light, where the power wires are, and have the controller in the cabin.

Tom... :slight_smile:

Thanks guys for your ideas. I will think about it for a while.

TomGeorge:
Hi,
To minimise current losses you could mount the MOSFET close to the light, where the power wires are, and have the controller in the cabin.

Tom... :slight_smile:

I wouldn't recommend this. If the wire to the gate picks up EMI it might cause all sorts of issues.