# Wiring Meanwell LLD driver for dimming



## neon822 (Mar 13, 2014)

Hi all! I wanted to wire in the dimming circut to my meanwell LDD-1500LW driver (I believe it has a built in PWM, but I don't know). I would like to go the most efficient and smallest size (fitting into flashlight). I see by there diagram that you can connect the dimming wire to Vin, or they have the option of using a PWM. I see that the voltage across the direct hookup is 0.5v-2.5V. Does this mean that I would need to wire a voltage regulator in between the two if I went that route? ...and is it possible to wiring something that would use the PWM function on the led? I'm not sure if I need a device to run the PWD or if the led driver will do that it's self?

http://www.meanwell.com/search/LDD-L/default.htm Page 5 has the wiring diagram


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## RetroTechie (Mar 13, 2014)

The way I read it, with 0.5-2.5V DC on its "dimming" input, the LED driver regulates the output current to some % of full power. Below and above that, it's full-off or full-on, but with the option to use rapid on-off (PWM, up to 500 Hz in this case) to control LED power. So you have 2 control methods to choose from.

Something like a 3.0 / 3.3V fixed output voltage regulator ($ 0.50 a piece or so) plus a potentiometer across its output (center tap to driver's dimming input) might work. Unfortunately datasheet isn't clear about what impedance the dimming input has (1mA at PWM dimming OFF and 24VDC input?). So that might take some experimenting / measurements. And/or fire of a mail to manufacturer... :thinking:


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