Meanwell LDD driver: for those who want to dim to 0 using Arduino

Ah, nevermind. I cut the green so short that I missed it. I have a three-prong that should work :headwally:

As far as the power supply is concerned, I'll have to check those out. Was I right about how you connect the drivers to the power supply though?

Yes, all of the terminals of the power supplies like those go to the same place, just makes it convenient to not have to try and hook up a bunch of wires to only one outlet. :)
 
What did I do wrong?



When the transistor is connected to ground or +5 the voltage from the 36v supply drops to 31.5v across the +/- of the LDD. When not connected to anything, voltage after the transistor is 25.8V.

BTW This is using analog dimming in case your wondering what the resistor and cap is for. It turns an arduino's PWM output to an analog output.
 
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What did I do wrong?



When the transistor is connected to ground or +5 the voltage from the 36v supply drops to 31.5v across the +/- of the LDD. When not connected to anything, voltage after the transistor is 25.8V.

BTW This is using analog dimming in case your wondering what the resistor and cap is for. It turns an arduino's PWM output to an analog output.

first I'm going to admit my ignorance on some of the nuts and bolts of circuit design .. BUT..
This is how it should be done for the R/c circuit at the end of PWM +
Of course this will roughly give you 0-5V..
pwm-filter.jpg


PWM neg pin is tied to PS ground..

http://arduino-info.wikispaces.com/Analog-Output

The LDD inputs from the PS are "isolated" from the + of the PWM circuit..
(Except tied to ground)
Not seeing that in your diagram..

I'm still not convinced your analog dimming has any effectively different "output" than sticking w/ PWM dimming..

your making this too complicated for yourself..
 
Jedi, what's the difference between HTC and CLG? Also, what's the significance of IP65 and IP67?
The HLG is the newer version of the CLG, higher efficiency seems to be the only difference.

IP ratings are for dustproof and waterproof, among other things. http://en.wikipedia.org/wiki/IP_Code

IP65 means that it is dust-tight and water resistant to jets of water spraying onto it for at least 15 minutes.

IP67 means that it is dust-tight and immersible up to 1m for at least 30 minutes.
 
If my power supply has water sprayed on it for 15 minutes, I've got more problems than a wet power supply.

It's kinda like the wrist watch that is waterproof to 200 feet. If I get deeper than 200 feet I've got more problems than water in my watch!
 
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If my power supply has water sprayed on it for 15 minutes, I've got more problems than a wet power supply.

It's kinda like the wrist watch that is waterproof to 200 feet. If I get deeper than 200 feet I got more problems than water in my watch!
But would you rather have a power supply that in the event of a catastrophe would NOT die and possibly take the rest of your lighting with it or one that gives up the ghost immediately? ;)
 
What did I do wrong?



When the transistor is connected to ground or +5 the voltage from the 36v supply drops to 31.5v across the +/- of the LDD. When not connected to anything, voltage after the transistor is 25.8V.

BTW This is using analog dimming in case your wondering what the resistor and cap is for. It turns an arduino's PWM output to an analog output.

I figured it out, and feel really stupid.

The arduino and the LDD circuit did not share a common ground. Once I connected their grounds together the entire thing started working correctly.

Oreo,

I have explained this a few times now. I do not want to risk running my LEDs at full current and lowering the life of the drastically. If I were to just use PWM dimming I would be running them at 1500mA, and maxing them out. With analog dimming I can run them at any amperage I desire. I have chosen 1350 mA.

With my design I can now use both analog and PWM dimming. I dim analog at the dimming pin, and PWM dim at the transistor.

Anyone see any issues?
 
y. If I were to just use PWM dimming I would be running them at 1500mA, and maxing them out. With analog dimming I can run them at any amperage I desire. I have chosen 1350 mA.

And I've mentioned a dozen times analog "dimming" does NOT necessarily mean analog output..
your ***-u-me-ing something that may not exist..
I'm not convinced that the waveform out of the driver is any different than w/ the PWM dimming..
I may be wrong.. Currently I'm not thinking I am..
If you have some proof i.e an oscilloscope trace of the output using analog vs PWM I'd really like to see it..
 
I do not, but I will trust the word I received from Meanwell technical support. Now until someone does prove me wrong I am going to choose to end this argument and not :deadhorse:...
 
I do not, but I will trust the word I received from Meanwell technical support. Now until someone does prove me wrong I am going to choose to end this argument and not :deadhorse:...

What did they say.. Hey I don't like to carry an incorrect hypothesis.. and this is the first you mentioned of this.. Sharing is part of a community. ;)
 
What did they say.. Hey I don't like to carry an incorrect hypothesis.. and this is the first you mentioned of this.. Sharing is part of a community. ;)
No it's not - I think you must have missed some posts (unless it was in another thread?). It was quoted a while back, along with quotes from the data sheet saying the output signal changes to PWM when the dimming signal is PWM (clearly suggesing it is analogue when analogue dimming).

Tim
 
No it's not - I think you must have missed some posts (unless it was in another thread?). It was quoted a while back, along with quotes from the data sheet saying the output signal changes to PWM when the dimming signal is PWM (clearly suggesing it is analogue when analogue dimming).

Tim

PWSTYLE.JPG


The "verbage" is misleading as are the graphs and I am not "personally" convinced it means what most think it means..

Maybe it does..On the surface it looks correct.. Just playing "doubting Thomas" here..

Just for clarity.. I bet I could find an analog dimmed LED using a PWM "signal" and there are plenty of "analog dimmed" drivers w/ PWM output..

W/ my very limited understanding of driver topology, in order to "change" the output you'd need the dim pin to affect the V sense resistor.. and shift to not affecting this w/ a PWM input..
http://www.ti.com/lit/an/snva605/snva605.pdf
 
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But what about the reply from meanwell, which seems pretty explicit:
???

Tim
This one:
Hi Steven,

When using the analog dimming function on the LDD 1000-1500, the led driver dim the LED by reducing the output current. The output current can be reduced by adjusting the external voltage source.

Yes, you are correct. According to the dimming chart on the datasheet, the output current will be reduced to ~85% of the rated output current when you apply 2.2V to the dimming pin.

Regards,

Mason Tang| Applications Engineer
Mean Well USA, Inc.
44030 Fremont Blvd., Fremont, CA 94538
United States

your not going to like my answer.... ;)

I'm not believing he is stating it correctly..
Look at the graph for the PWM output.. It states the exact same thing..

AT a 50% duty cycle the "output" I(o) is 50%..LOOKING at the PWM signal AND output waveform on the right.. it shows a 50% "on" and 50% "off" cycle.. yet they "imply" 50% current reduction..
AT 85% duty cyle the chart shows 85% reduction in Amp output.
Which is TRUE based on a time average.. Granted that dealing w/ a multiple set of drivers this is the only logical way to present it..
Get my drift...

I'm done discussing this here.. BTW.. pointless w/out a measurement of the output via oscilloscope. as a side note these "drivers" are basically buck switching power supplies.
Whats beating a dead horse is talking w/ out "real" data...

switch.jpg

http://ledlight.osram-os.com/wp-con...Ds_Switch_Mode_Drivers_v6_12-23-11_SCRIPT.pdf
THIS is how a (well most current) driver works Dimmed or not.....
switch2.jpg


AFAICT......... what does that tell you?
 
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