Meanwell LDD dimming vs amps

[blitz49]

Trying to get input on an led build that I will be doing soon. Have questions regarding meanwell LLD drivers, and hope to understand how these drivers work.

1. If I am using 1000 ma LLD driver, and I dimmed it to 50% would the amp draw still be 1000 ma but the LLD driver reduce the amp draw?

2. Would it be better to use 500 or 700 ma if I was dimming my leds 50% or lower?

All information will be greatly appreciated.

Thanks

 

[Gorgok]

The LDD will be driving at rated numbers always, just turning on and off rapidly to meet the duty cycle (dimming) you asked for. But thats output stuff, not input.

The amp draw would depend on voltage its receiving and outputting and will probably be chopped up like the output current when dimming, so its still hitting the peaks. Datasheet says at max load (48V in, 45V out in test) it will draw 900 mA when pushing 1000 mA.

 

[oreo57]

Trying to get input on an led build that I will be doing soon. Have questions regarding meanwell LLD drivers, and hope to understand how these drivers work.

1. If I am using 1000 ma LLD driver, and I dimmed it to 50% would the amp draw still be 1000 ma but the LLD driver reduce the amp draw?

2. Would it be better to use 500 or 700 ma if I was dimming my leds 50% or lower?

All information will be greatly appreciated.

Thanks

LDD output at approx 50% dimming:

 

[blitz49]

The LDD will be driving at rated numbers always, just turning on and off rapidly to meet the duty cycle (dimming) you asked for. But thats output stuff, not input.

The amp draw would depend on voltage its receiving and outputting and will probably be chopped up like the output current when dimming, so its still hitting the peaks. Datasheet says at max load (48V in, 45V out in test) it will draw 900 mA when pushing 1000 mA.

So dimming will still hit the led peak and draw the 1000ma, but just turns on/off to dimming percentage set?

LDD output at approx 50% dimming:

Sorry, still trying to learn, and I don't know what the graph means. Just started playing with LDD, and trying to learn how it works.

 

[Gorgok]

So dimming will still hit the led peak and draw the 1000ma, but just turns on/off to dimming percentage set?

Yes. Lower dimming will mean its off longer, on shorter each cycle, and vice versa. Based on that scope screenshot its doing it at 490 Hz.

 

[oreo57]

So dimming will still hit the led peak and draw the 1000ma, but just turns on/off to dimming percentage set?

yes

 

[blitz49]

Thanks for the info guys. Makes sense to me now how meanwell ldd works with pwm.

 

[oreo57]

Thanks for the info guys. Makes sense to me now how meanwell ldd works with pwm.

not to confuse you more.. but "signal" doesn't always reflect output..

Even drivers using 0-10V dimming can have the same PWM output..

Just an FYI..

In the case of the LDD it does though..

 

[perkint]

Datasheet says at max load (48V in, 45V out in test) it will draw 900 mA when pushing 1000 mA.

I know that's what the data sheet says, but two things spring to mind:
1. Max input is 56V not the 48V reportedly used for that test.
2. 48V and 0.9A is 43.2W. 45V and 1A is 45W so those figures suggest the LDD is actually generating extra energy when on full load :lolspin:

Oreo57 - CIO would be proud to know his screen shots are still doing the rounds Does it mean I'm sad that I recognise them?

Tim

 

[oreo57]

Oreo57 - CIO would be proud to know his screen shots are still doing the rounds Does it mean I'm sad that I recognise them?

Tim

Finding those saved me from using my soundcard as a o-scope to check for myself...
Pretty sure I'd eventually fry it..

 

[blitz49]

not to confuse you more.. but "signal" doesn't always reflect output..

Even drivers using 0-10V dimming can have the same PWM output..

Just an FYI..

In the case of the LDD it does though..

Good to know. I thought how dimming worked for meanwell ldd was by reducing voltage or current. But that didn't really make sense to me because why would we need a 0-10V external power source? Guess i was just thinking how analog works not digital.

 

[oreo57]

Good to know. I thought how dimming worked for meanwell ldd was by reducing voltage or current. But that didn't really make sense to me because why would we need a 0-10V external power source? Guess i was just thinking how analog works not digital.

Well there are "multi-protocol" drivers that can use either analog (0-10V) OR PWM.. BUT in analog it controls the current.. In digital mode it pulses the voltage..

Or drivers that use both analog and digital BUT output strictly PWM..

You really need to know the driver...
Never assume...

 

[perkint]

Finding those saved me from using my soundcard as a o-scope to check for myself...
Pretty sure I'd eventually fry it..

LOL - sounds like a risky idea!

Surprised you haven't picked up a USB 'scope!

Tim

 

[oreo57]

image

image

LOL - sounds like a risky idea!

Surprised you haven't picked up a USB 'scope!

Tim

When I was orig. looking they weren't so cheap
Scope software using the ADC converter in the sound card was cheap i.e free..
I have plenty of computers and cards..

for fun 60% PWM @ 10V typhon. Never adj. scale: