Meanwell LDD driver: for those who want to dim to 0 using Arduino
- Thread starter pwreef
- Start date
jedimasterben
LED world domination!
They're rated for 50,000 hours at 700mA and 135°C, so running them at 1000mA at 85°C or less (which is above what most actively cooled arrays run at) you're more than fine.
Actually that's an absolute maximum rating of 135°C and 1050mA. (levels at which the LEDs started failing at a rate that exceeded the test parameters threshold of failure) While most DIYer's max out their LEDs with no bad effects it is usually due to them also having them dimmed down quite a bit.
To achieve 50,000hrs with the performance on the data sheet the same conditions must be maintained, which are 700mA and a junction temp of 85°C. Junction temp is not the same as the temp of the heatsink, it is much higher than the temp you can measure at the heatsink, just keep that in mind.
70% of maximum rating is really the highest anyone should use for long term reliability and peace of mind, but let's face it people replace stuff long before it's worn out these days anyway, so go for it. As already mentioned you'll likely be running this monster dimmed down quite a bit so it will be fine.
jedimasterben
LED world domination!
Interesting, they revised the data sheet since I downloaded it this spring.
The key words there still being "of up to 700mA" and "at or below 135 C" they don't state that they will operate at both 700mA and 135 C, (though under the right conditions they may well be capable of that) only that they are tested and binned at 700mA and 85 C.
Anyway, like we've said he'll likely never run this setup at 100% duty cycle anyway so it won't be an issue, but lower current will definitely increase efficiency and life span of the LEDs when he gets things acclimated and finds they are not running near full power. Would it justify the cost of buying new drivers? Couldn't say, depends on how much power costs there........
1500ma? Jeez- I'm hoping that it's not a TYPO. Gonna do some digging on the Ol' NET and see if I can find any further info.
That's no TYPO.:celeb2: There's 3 versions of the 1500ma version, and 3 versions of a 1200ma version. The only difference that I can see is a slightly lower output of only 30V on the high amp models. Check it out >>>http://www.powergatellc.com/mean-well-ldd-l-dc-dc-converter.html
Whoa! Horsey Whoa! There's no LDD-"H" yet. We need a bit more forward voltage output before we can start the celebration. 30V isn't gonna be enough for most of the multichips that we're running. We'll need north of 36V before the real partying can begin.
I was just looking over the data sheet now, and the high current moddels are the same size as the LDD-H!
O2 can you double check but it looks like the PWM pin is in a different location, othewise they seem to use the same pin configuration as the LDD-H. You could make a quick modification the the boards to accommodate both drivers.....
O2 can you double check but it looks like the PWM pin is in a different location, othewise they seem to use the same pin configuration as the LDD-H. You could make a quick modification the the boards to accommodate both drivers.....
Yep- You're right. They're the same size and the same pin configuration as the LDD-H, except for the PWM pin. It's been moved from pin #22 to pin #21. That's not a big deal for users that have chip holders mounted to their PcB's. All that would be needed is a little "solder bridge" between pin #22 and pin #21 of the chip holder and you'd be able to use either version of the LDD.
I'm going to take the time to create a new EAGLE library for the new version of the LDD-L and incorporate it into future PcB designs.
The Dream Chip fv is 31.5v-36v with a 1400ma max @ channel.What would happen if you only supplied the 30v at 1400ma?---Rick
Remember- an Led's Vf rises with the current consumed. You won't get 1400ma through the led with only a 30V driver. Chances are good that you'll need at least 36V with a few extra volts as"headroom" for the LDD-1500L to drive a dream chip to 1400ma.
jedimasterben
LED world domination!
Why do you need different input voltages? The LDD auto adjust the output to match the LEDs.
