LED Driver driving LED driver?

Discussion in 'General Electronics Chat' started by spinnaker, Dec 23, 2015.

  1. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
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    My current LED sign light has a LED driver that is external to the light. The driver is actually a part of the controller that operates the light. The driver doubles as a +5VDC power source for a Pic. The driver regulates current to 640ma to the light.

    My original plan was to replace the LED driver with a pin compatible module that was pin compatible to the driver with a LM2675-5 for the pic and supplied +12VDC direct to the light. Figuring the current requirements of the light would exceed the 640ma currently being supplied.

    I just got the light in and hooked it to my bench supply. It is nice and bright and consumes a mere 250ma! Well below what is supplied by the light.

    The current light is on it's last legs and I am anxious to get the new light installed. Are there any issues with a LED driver driving another LED driver?

    No data on the light. Just one of those cheap LED flood lights found on Ebay.

    Here is the driver
    http://www.luxdrive.com/content/07021_07023_V2.2.pdf

    It is the 700ma adjustable version set to 640ma.
     
    Last edited: Dec 23, 2015
  2. cmartinez

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    Jan 17, 2007
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    I'm not sure I understand... do you intend to connect the new driver in parallel with the other one, or to make the new driver feed the old one?
     
  3. spinnaker

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    Essentially yes.

    The old driver is currently in the controller which I designed. That BuckPlus module you see is connected to the light. It is adjusted to 640ma. The new light has it's own PWM LED driver. So basically an LED driver will be supplying another LED driver. Eventually I want to eliminate that BuckPlus module that you see a replace it with a desing of my own minus the LED driver section.


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  4. cmartinez

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    Jan 17, 2007
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    Interesting... I really don't know that much about this subject to give you an informed opinion. But my first guess would be that there would be a drop in efficiency (probably not an issue for you) and therefore some heating (a probably important issue)
    Also, I'd consider the possibility of voltage drop between one stage and the next... see how it affects the result.
    Why don't you just build your circuit and connect a switch that would allow you to toggle between the one installed and the new one? That way if something goes wrong with the new circuit you could always switch back to the old one.
     
  5. spinnaker

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    Yeah I will probably end up waiting. Still waiting on the Mouser delivery.
     
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