:worship:worship :worship:worship:worship:worshipApologies for not responding earlier - I have been trying to get the controller sketch finished off ;)
What you are trying to achieve is best down in your Arduino sketch.
As for using a physical switch, I would need to do some testing - switching the PWM control wire MAY work but this is not the same as outputting a zero duty cycle PWM signal so I am not sure. Putting the switch on the LED string would obviously work and shouldn't do the driver any damage although the minimum output voltage as per the spec sheet is around 2v so I would not guarantee that some smoke would not escape somewhere.
I will see if I can do some testing tomorrow night.
And how is it going ehre @MagicJ ;)Apologies for not responding earlier - I have been trying to get the controller sketch finished off ;)
Hi @Terminatermule, my highest demand string is only about 45 volts and fair to say most of my strings would be well under that even. Early days for my set up but I haven't experienced any issues with my 48 volt supply set up yet.Thanks magicJ,
A quick question about these, I have 8 channels (colours) that I wish to run all separately, and dim separately but some of the strings will have different input requirements, with the LDD (I know I could just read the Datasheet but thought you guys may have practical experience with this in the real world) how much difference can it tolerate, and does it get really hot when there is such a difference? I know with the cat4101s it can be a serious issue, I had designed my drivers with a reg in front of every cat with a trim pot for this very reason. That way I could run the highest voltage needed for the highest/longest string on the LED array and a run a volt or so less for a few of the other strings. Is this not needed on these?
Edit:
Ok so I just read the data sheets, and aside from a drop in efficiency by driving fewer LEDs at a higher input voltage, it can cope with it just fine, unlike the CAT4101's. I like this chip more and more, so just to be sure, from those of you doing this, I have most of my strings now laid out to run 48v input, but there will be a couple that are 24 volt strings, however this seems to be perfectly fine, just not as efficient. Is that correct? I guess this chip being buck type oesn't need to sink the remainder, it just doesn't generate it?
Also MagicJ, how many of the boards/sockets/pins do you have atm? I think I would like to buy three lots of those if you have them spare. Other wise I will put in an order with seeed.
Also ( I may have asked this prior) do you have an eagle file for this board? Would like to tinker with it a little.
Cheers Glenn
As you noted in your edit, these LDD's are pretty handy things - they don't need to sink the excess voltage. I had some concerns over generated heat and ran a test with one led running through a 500mA LDD and a 48v power supply - this is a graph of the heat of the LDD (as measured by a DS18B20 fixed to the LDD)Thanks magicJ,
A quick question about these, I have 8 channels (colours) that I wish to run all separately, and dim separately but some of the strings will have different input requirements, with the LDD (I know I could just read the Datasheet but thought you guys may have practical experience with this in the real world) how much difference can it tolerate, and does it get really hot when there is such a difference? I know with the cat4101s it can be a serious issue, I had designed my drivers with a reg in front of every cat with a trim pot for this very reason. That way I could run the highest voltage needed for the highest/longest string on the LED array and a run a volt or so less for a few of the other strings. Is this not needed on these?
Edit:
Ok so I just read the data sheets, and aside from a drop in efficiency by driving fewer LEDs at a higher input voltage, it can cope with it just fine, unlike the CAT4101's. I like this chip more and more, so just to be sure, from those of you doing this, I have most of my strings now laid out to run 48v input, but there will be a couple that are 24 volt strings, however this seems to be perfectly fine, just not as efficient. Is that correct? I guess this chip being buck type oesn't need to sink the remainder, it just doesn't generate it?
Also MagicJ, how many of the boards/sockets/pins do you have atm? I think I would like to buy three lots of those if you have them spare. Other wise I will put in an order with seeed.
Also ( I may have asked this prior) do you have an eagle file for this board? Would like to tinker with it a little.
Cheers Glenn
If that is what the spreadsheet said :p I would go a bit higher just so the supply is not operating at 100% all the time.so @MagicJ i will need a power supply with a 48 volt supply and going by your excel spread sheet 1 by 120w and 1 by can not remember?
so 48v 120w correct?