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post #16 of (permalink) Old 07-16-2012, 05:15 PM
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Join Date: Aug 2009
Location: Vancouver, WA, USA
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Originally Posted by O2surplus View Post
I think there may be misunderstanding with regards to how the "Analog Dimming" works with this driver. The CAT4101 IC normally uses a "Sense resistor" ( labeled RSense in the chips spec) to set it's upper current limit. The Chip can output up to 1000ma maximum, and that is set by installing a 549ohm resistor between the "RSense" pin and ground. This is how the driver is normally set up. If one wished to run the chip at 700ma instead of 1000ma, they'd have to install a 768ohm resistor instead of the 549ohm unit. I found this method of setting the current very cumbersome, so I installed a 10k trimmer pot inline with a 549 ohm resistor. This makes the output current fully adjustable ( 50 - 1000ma ) and there's no further need to desolder/solder resistors to change the output current. With 6 CAT4101's on board, this driver will be able to handle up to 150 watts worth of leds, that's 6 - 8 3W leds per channel or 36 -48 3W leds per driver board. The beautiful part of this driver is, once the maximum current per channel is set, (using the Analog current Pots) Each of the six channels can be programmed to dim via PWM signals provided by the on board Arduino microcontroller.
I put in the order for the PCB's and they're already in production,so I should have them in my hands in a week or so. I'm going to build 3 of them for my own use and then maybe pass out a few to people with coding experience, that will hopefully be able to show us all - How to take full advantage of this design. I'm a total NOOB with coding so I could use the additional help. ( This is code speak- for getting "SINK" to chime in )
Whoops haha... Well, I never claimed to be an expert. That makes sense, though. So it can operate as a kind of 'driverless' controller? And the current for each channel is adjustable similar to a MeanWell driver? Up to 48 LEDs?

If i understand this correctly now, that makes this capable of doing all the work (driving, dimming, and controlling) for just about any size build, providing there is no minimum quantity of LEDs per channel? Wicked cool! This could save DIY'ers a ton of cash on separate drivers and controllers.
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