constant current LED driver without PWM (and flicker)

[smilem]

Hello, I chosen the sharp LED GW5DGE40MR5
http://www.newark.com/sharp/gw5dle40mr5/megazeni-white-50w-4000k/dp/89T3708

The driver is mystery to me, I need no flicker (means no PWM).
Would this Mean Well work:

http://www.meanwell.com/mw_search/ldd-h/LDD-H-SPEC.PDF

Perhaps it's better to use dedicated 240AC to DC supply? Then to use some Laptop 18.5V and this Mean Well?

 

[Colin Mitchell]

Don't you understand? The item is no longer manufactured.
No Longer Manufactured
It is 82 watts.
This project is way beyond your capabilities.
You have absolutely no idea what you are doing.

 

[smilem]

"Availability: No Longer Manufactured" is from newark.com. My local shop has plenty of them.
"It is 82 watts. " - that is why I will use CPU heatsink with fan.
Actually the datasheet tells it's 50-80W http://datasheet.octopart.com/GW5DGE40MR5-Sharp-Microelectronics-datasheet-10917188.pdf
Depends on current you drive it at. I don't like driving LED's at MAX, so 1amp will do fine plenty of power for me. It will replace 150W halogen bulb, so driving at 50W TDP is fine for me, it's 1/3rd of power usage.

 

[smilem]

I have bookmarked this driver for ages, it's what I need but 2.3x more expensive then LED
http://www.distrelec.biz/en/led-driver-1050-ma-recom-racd60-1050-of/p/16926637

 

[duke37]

A DC PWM supply can be smoothed to reduce any flicker. It will be much more efficient than a linear supply. The driver you show looks like a high frequency PWM circuit to me.

 

[smilem]

Every supply seem to be PWM more then less, this one is nice
http://www.distrelec.biz/en/led-dri...er_Buyable=1&page=3&origPageSize=25&simi=98.8

Has dimmer built in possibility with resistor, pwm, or voltage 1-10v. At 100% it isn't clear will it flicker or not?

 

[Kaj Lonnqvist]

Hi

PWM is not identical to flicker. If the switching frquency is low, you will see flicker. But already at 1 kHz or so, which is a low frquency, it is not possible to see any flicker (frequency limit is something like 70 to 80 Hz, above which the light is stable).
The converter you refer to above is a switch-mode power supply which probably has a switching frequency of 100 kHz or more (in order to keep the inductive components inside small in size). And NO flicker!

 

[cjdelphi]

Pulse width modulation, pwm usually comes at a set frequency, let's say 1000hz your eyes begin to drop the flicker after a few hundred hertz, but the on duration, it's pulse is varied meaning just the light intensity / current is changed..

The beauty of pwm vs cc for LEDs is it's color rendition, putting a cc through it say 100ma vs 1000ma can alter the colour, pwm will not

 

[duke37]

The beauty of pwm vs cc for LEDs is it's color rendition, putting a cc through it say 100ma vs 1000ma can alter the colour, pwm will not

Are you sure about this?
The mechanism I thought was that a photon was emitted when an electron and hole combined and the photon produced had an energy dependant on the band gap.

 

[cjdelphi]

I've read it to be true so many times lol

Maybe pure wavelengths produced are untouched, but but ones with coated phosphorous with a blue led under it, maybe they change colour...

But having to keep in the band gap would imply no colour change, but i've seen old square red LEDs go from red to orange even green, the new 5mm dome ones just fade out without any noticable wavelength shift...

 

[Sunricher]

A power supply with high PWM frequency will not flicker.

 

[BobK]

In addition to the info that PWM does no imply flicker, a constant current supply does not output a PWM waveform. It may use PWM for dimming, but if you are using that, there is no PWM.
Bob