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Author Topic: Does the NB use PWM/Duty Cycling to get its dimming?  (Read 1970 times)

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Offline hedgehog1

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Does the NB use PWM/Duty Cycling to get its dimming?
« on: March 27, 2013, 06:21:10 PM »
Erv,

Mikeclem on the TCSS web site is thinking of using the NB to drive PEX or MOSFET to run an LEDEngine GGGG or a TriRebel GGG. 

Does the NB use Pulse Width Modulation (Duty Cycling) to get it's dimming effects?  Otherwise he will need to search for another option.


Offline erv

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Re: Does the NB use PWM/Duty Cycling to get its dimming?
« Reply #1 on: March 31, 2013, 11:51:52 AM »
it does ! You can indeed use a bigger device but keep in mind the one on board can deal with up to 6.5A.

True though, it's a good idea to split the load with an external PEx if you really want to drive a GGGG, but I think the stock configuration of the NB can deal with it in direct drive.

Offline hedgehog1

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Re: Does the NB use PWM/Duty Cycling to get its dimming?
« Reply #2 on: March 31, 2013, 02:37:03 PM »
6.5 amps?  That is wonderful!  I love anything engineered with a 'safety margin' like that. You do good work...

Mike will be very pleased (Whereas I am just very, VERY impressed!).

Marc...

Offline DarthRaevus

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Re: Does the NB use PWM/Duty Cycling to get its dimming?
« Reply #3 on: March 31, 2013, 06:30:15 PM »
@Erv, I was under the impression that the board's limit was 2A for a direct drive... Or are you saying that if the battery solution would allow it, you could pull over 2A to a // Tri Rebel GGG setup? For instance 750mA each? And could you still use the board as a linear resistor?




Offline erv

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Re: Does the NB use PWM/Duty Cycling to get its dimming?
« Reply #4 on: March 31, 2013, 08:51:31 PM »
the part is rated up to 6.5A when in direct drive (not resisting).

And could you still use the board as a linear resistor?

with limits, as that will increase the heat. But staying in the 10-20% max (drive min = 850) it should be fine. I have made a few modded NB with a double output device for a high power led project and it worked fine.
Note however that when the current increase, it's best practice to have an EXTERNAL resistor. Using the board as a digital resistor for high current is inefficient and will lead to voltage ripple even if the cell is big enough (core voltage won't be regulated if the ripple is too high).

High power LEDs are meant to be current driven with the proper current driver for that reason (and that's why CF and PC are equipped with such a system, which also enhanced battery life and runtime).

Offline DarthRaevus

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Re: Does the NB use PWM/Duty Cycling to get its dimming?
« Reply #5 on: April 01, 2013, 03:37:13 AM »
Right, don't want components melting off the board, I gotcha, lol. Good to know, thanks Erv!




 

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