Specialty Driver Application -- Any Advice?

[EthanOConnor]

Hello All,

This is my first CPF post -- I've been a little obsessed with light sources ever since age 3 when my dad took me into the back yard at night, shined a flashlight at Proxima Centauri, and told me that in four years the light would reach it...
:candle:

Anyway, I have a lighting application in which I need to modulate 6 power LEDs independently from full off to full on at varying intervals aligned on a ~180hz clock. I have 8 channels of 5v / 40ma sources at my disposal, and I'm hoping there's a nearly-off-the-shelf solution that's essentially 5v/0v in on 6 pins to control 6 LED drivers.

This isn't a particularly challenging task, and I can rig something up from scratch if necessary, but it's not really my forté

I'm probably going to be using Rebel tri-stars wired in parallel @ 350ma.


Anyway, I'll post some pics and video of this application once it is up and running -- sorry to be vague for now.

Thanks to anyone with a suggestion!



Ethan O'Connor

 

[EthanOConnor]

For the initial prototypes I don't need the full brightness (thermal testing aside) so I'm trying the Maxim MAX16825, which is a three-channel, 150ma/channel current limiter with independent control of the channels at up to 1mhz, with easy daisy-chaining of chips for more channels running on the same control stream. External component count is two caps and three sense resistors...

Still looking around for a solution that'll provide similar ease of integration and control in the 350-700+ma/channel range. Package size isn't too important.

Thanks for any thoughts! I will post here with what I end up going with.

 

[Magic Matt]

I'm pretty sure you wont get something off the shelf for this.

The only thing I could think of would be a PIC processor and manually generate the clock output duty cycles on the output pins - get one with it's own clock generator and you don't need any other components - you can literally run a PIC direct off a 3V cell (CMOS PICs are happy across 2V to 5.5V I believe). The sort of PIC chips I use only have one programmable PWM output - obviously you could use 6 small PIC chips and do it that way. Downside is unless you already use them you'll need to learn to programme them and get a programmer.

If you want the individual control to be automated in any way (fading from one setup to another for example) then I think PIC is the simplest way to go.