MOSFET current limit

[Borisw37]

I'm currently using relatively expensive MOSFETs (IPS6021) that have built in over current and over temperature protection. I do not use the "diagnostic" feature of the device.
I would like to use the much cheaper simple MOSFETs and use external circuitry for current limiting.
The goal is to have a high side switch capable of ~10A @ 12V. The current limit does not need to be precise, but below the MAX current rating for the MOSFET I choose.
Since these switches will be used in large quantities, a $1 per switch savings does make a difference.
Any suggestions?

P.S. Perhaps there are cheaper self-protected MOSFETS.

 

[crutschow]

How much voltage drop can you tolerate for this current limit?

An easy way to limit current is to use an NPN transistor to sense the voltage drop across a resistor in the MOSFET source circuit which then reduces the MOSFET gate voltage, but that requires about a 0.6-0.7V resistor drop at the current limit value. (See this for example).

 

[Jaguarjoe]

How about a PTC Polyfuse?