PWM Dimming Meanwell LDD-L ? - The Planted Tank Forum
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post #1 of 4 (permalink) Old 07-19-2017, 12:07 AM Thread Starter
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PWM Dimming Meanwell LDD-L ?

I have decided to use Meanwell LDD-L drivers in my next DIY lighting project.

LDD-L Series Mean Well Step-Down Mode CC LED Drivers

This driver supports PWM dimming, and the higher current models also support analog dimming.

I researched the analog dimming route. It requires a small circuit with a voltage regulator (to lower voltage from 24V to 2.5V), some resistors and caps, and a potentiometer (voltage divider) to allow sweep between 0-2.5V. These parts added up, $3-5 per channel. I need six channels.

How does PWM dimming work with these drivers? Is there a single PWM dimmer you use inline with the driver? Something like this:

Or.. are they designed to use exclusively with a digital dimming controller?

Its possible that PWM dimming could be less expensive than analog. Need to understand methods for PWM dimming the LDD-L before I can make that decision.
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post #2 of 4 (permalink) Old 07-19-2017, 12:19 AM
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Nobody does the .5V to 2,5V analog dimming..
and that dimmer won't work w/ an LDD due to it won't work below about 9V. Def not in the LDD-H or LDD-L pwm voltage range
Possibly in the 350-700mA LDD-l since it will go up to 8V..but you would need to power it w/ 8 or less (till it doesn't work) volts..
TC-420 is the simplest cheapest controller , once "hacked" for Meanwell LDD's

Connecting high power LEDs to the TC420

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post #3 of 4 (permalink) Old 07-19-2017, 12:36 AM Thread Starter
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Have I got this right, the TC-420 is only 30 bucks?
TC420 1.4" LED Programmable Time Controller - Black (12~24V) - Free Shipping - DealExtreme

The plan so far is this: For my existing light bar with 30x 6500k, add three RGB channels. There will be six RGB combined "1W" LEDs, each channel will have six leds. LEDs organized in parallel/series array to meet 1000mA.

There will be three LDD-L drivers powered by one 65W/24V supply. It is enough to cover the needs of all three channels on full.

The analog dimming strategy involves reducing 24V down to 2.5V then using a voltage divider (pot) to select in the range of 0-2.5V. Each channel will require a voltage regulator, some caps and resistors, and a pot (value and form factor tbd.) Estimated $3-5 per channel. The advantage of this method is that everything is self contained, there will be three independent pots to control R, G, and B. Very easy to use.

The PWM strategy.. depends on the capabilities of the typhoon.

* How many channels can it control? I need six channels.
* How easy is it to adjust RGB? It looks like it would be a PITA, nowhere near as easy as three pots.

The idea is that I can add whatever mix of White/Full Spectrum/etc leds to the main channel (which has three settings) and then use the RGB to create the perfect viewing experience. This way I don't have to keep physically swapping color leds.

The analog solution can be done for $35-40 per side.
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post #4 of 4 (permalink) Old 07-19-2017, 02:48 AM
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yea tc-420's are relatively cheap..Only 5ch though..
LM2596S-ADJ DC-DC Buck Adjustable Step-Down Power Supply Converter 3A Max Pbs
voltage regulator
22 cents so far..

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