>> OK. I've uploaded a quick drawing to imageshack. PLEASE forgive the hand
>> drawing. I'm awful at getting this stuff into schematic software.
>> http://img386.imageshack.us/img386/9920/pwmschemajx8.jpg

> Couple of questions.

> 1) Why are you driving the high side of the bulb instead of the ground
> side. Ground side is much easier becaust eh source is at ground so the
> gate driver can be referenced to ground. Unless it is a P-channel and VIN
> is less than 15V you're probabbly better off with a low side N-channel
> (they are more robust).

> 2) Why use Comverter.  Average should be fine as you are only going to
> create a DC average.  for average its as simple as a R-C if the pwm
> frequency is high enough or a multi pole active filter. if it is lower.

> If you comare average voltage in with a variable reference, you can have a
> adjustable brightness curcuit that is linar with your pot adjustment
> andfixed from external changes in VIN or temperature.