# How to dim this LED driver



## Palm Tree (21 Aug 2013)

Hi all,
I am looking for a way to dim this LED driver, I think its PWM that I would need but I am not sure which one to choose.This would be used to power 10x3w LEDs on a PCB. The specs are as follows:
Ideal for 6~12pcs 3 watt high power leds.
Input Voltage: AC 80V~140V/AC 180V~240V (will send based on buyer's shipping address)
Output Voltage: DC 18V~42V
Output Current: 650mA
RF: 0.94
TC: 65 Deg C
TA: -50- 65 Deg C (MAX)
Waterproof Rating: IP67
Size: 138mmx44mmx26mm

Function: Open circuit, Short circuit and Over loading, Dimmer
Any help would be appreciated.


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## Ichthyologist (23 Aug 2013)

See my thread below for a solution, I used a DC motor PWM speed controller.
Re the above, I can not see how a 650mA driver can power 12x3w. How many LEDs are you trying to drive?


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## AshRolls (23 Aug 2013)

650mA would still be very bright if the they are top end CREE LED's such as the recent XM-L2. You can drive them, theoretically, up to 3A though that would need liquid nitrogen to cool I expect!

*edit* I just checked the XM-L2 data sheet and they chuck out around 400 lumen each at 1000mA. 300 Lumen at 700mA.

*edit2* these drivers are variable voltage (within spec'd range), constant current.


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## Palm Tree (23 Aug 2013)

Ichthyologist said:


> See my thread below for a solution, I used a DC motor PWM speed controller.
> Re the above, I can not see how a 650mA driver can power 12x3w. How many LEDs are you trying to drive?


10x3w leds, i know it works on 100% as I have tried it and its very bright but the dimming is the problem.


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## Ichthyologist (23 Aug 2013)

Palm Tree said:


> 10x3w leds, i know it works on 100% as I have tried it and its very bright but the dimming is the problem.


PM me your address, I will post you a spare 8w PWM dimmer you can try.


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## Palm Tree (23 Aug 2013)

That would be great thanks, I'm still not sure on how to set it up properly though.


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## Ichthyologist (23 Aug 2013)

Kinetic imgur Upload


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## Ichthyologist (23 Aug 2013)

Wiring diagram here  Mini In-Line led Dimmer Switch Controller LED Strips Light with On/Off Caravan | eBay


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## Palm Tree (31 Aug 2013)

Ok, I was wrong as I now remember it is 12x3w LED's. They are 3.3v each so 3.3vx12= 39.6v. The driver is constant current (650mA+-5%) 25-42v DC. At 100% brightness they should draw roughly 25.35w.
@Ichthyologist I have tried the dimmer you sent me but it only flashes and stays on, even if I only press the dimming setting. It also was very warm after 5 seconds, which I think may be because its rated 12v.
I have found this-  9V-60V 20A DC Pulse Width Motor Speed Control PWM Controller Dimmer with Switch | eBay
Its a 9-60v 20A 600w max PWM dimmer, my question is would this be overkill or would it work fine?


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