LED Driver driving LED driver?

Thread Starter

spinnaker

Joined Oct 29, 2009
7,837
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:

cmartinez

Joined Jan 17, 2007
6,771
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?
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?
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,837
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.



 

cmartinez

Joined Jan 17, 2007
6,771
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.
 
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