RGB LED driver, Any comments?

[skimask]

Hey SkiMask, if you can change a busted cam belt and swap a few valves, i have a Twin Turbo charged Metallic Black Nissan 300ZX sitting here with your name on it.

Ouch! Ya have to hate it when that happens!
Much as I'd LOOOOOOOVE to fly over and get my hands dirty, I'd have a helluva time trying to drive it back

Wait a minute...I thought Nissan has always used timing chains instead of belts. I've got a '98 200SX/SE, took it to the shop to buy an oil seal for the crank, asked about getting a new timing belt. They said they'd do it for $5 in labor and do it in 10 minutes. That's when I figured out my engine used chains instead of belts The mechanic said Nissan's have always used chains (then again, he was a bit doofy looking), probably didn't know what he was talking about...

[T.Jackson]

What a ride! That thing fitted me like hand-to-glove. Doubt too many people would really say much otherwise though. Shame about my current car, he's not all there, just have to ignore it I guess.

[cjurczak]

Seems everyone is using MOSFETs to switch their RGB leds, any reason not to use a darlington pair?

[skimask]

Seems everyone is using MOSFETs to switch their RGB leds, any reason not to use a darlington pair?

MOSFETs don't have a secondary breakdown when they overheat, so less chance of burning up. Mainly, no base resistor needed, lower drain-source resistance, practically zero gate current required (gate cap's make it draw a bit of current at high freq's, not much though.

The list goes on...

[T.Jackson]

MOSFETS are a voltage controlled current source as apposed to BJT's which are a current controlled voltage source. FETs in general have a relatively higher impedance than their BJT counterparts.

I think there's a lot of personal preference between the two. I will make a bold statement and say that "BJTs make better audio amplifiers" In many cases, either of the two can be made to work.

[Docedison]

No, however they will require more heat sinking than a Mosfet of equivalent current capacity. Since it is a switch (PWM) the LOW RDSon of most all power mosfets < .1 Ohm Vs a VCEsat of > 1Volt makes it a kinda No Brainer unless all you have are some tip121's? I don't remember which... But @5V gate voltage an IRF 540 is hard to beat for a GP Power Mosfet.
Doc