I would like to have 4 350ma capable LEDs running my brake lights, one current source running 200mA for the running lights, and then go to 350mA for when I hit the brakes. The problem is that I have 2 positive inputs +12v, and one common ground... Both +12v inputs stay on so normally a smaller filament is lit, and when the second input is activated a second filament is lit, so both are lit at the same time... that's the problem I think... If they were mutually exclusive I could use a 200 and 350ma current source, but I don't know how to turn one off if the other is on?
So I was thinking of using two constant current regulators (possibly the switching regulators I am working on in the projects forum) in parallel, or simply a LM317 in constant Current mode...
Does that make sense, Like 150+200= 350mA? Or would that mess with the current sensing of the chip?
I could do some finagled relay setup, where the first current source is turned off when the second one is triggered, but I'd rather use something solid state if possible to not have any moving parts, and to utilize the speed of the LEDs.
Thanks for the help, Bill
So I was thinking of using two constant current regulators (possibly the switching regulators I am working on in the projects forum) in parallel, or simply a LM317 in constant Current mode...
Does that make sense, Like 150+200= 350mA? Or would that mess with the current sensing of the chip?
I could do some finagled relay setup, where the first current source is turned off when the second one is triggered, but I'd rather use something solid state if possible to not have any moving parts, and to utilize the speed of the LEDs.
Thanks for the help, Bill