LDD Drivers Help

[tet024]

Hi Guys,


After frying a couple of leds I came to the below conclusion. Could someone please tell me if i'm on the right track or not? For this test i'm using an LDD Driver and PI to DIM the leds.


For example if i'm using the LDD-700 this would constantly output 700ma of current. Now if i have a string of 10 leds in which each led has a working 3.3v and working current of 700ma. The voltage drop across the leds would be that of round about 33v. Now if the input of the LDD drivers would be of 40v and PWM 4096 it would output 40v so I would need to limit the MAX PWM to 3000 for example to meet the 33v output.


I gave the following example because i shall be having different LED's channels which have different voltage drop so I my conclusion was to check with a multi-meter the output voltage of the LDD driver and limit the MAX PWM to that voltage.


Am i on the right track or not?


My setup is as follows maybe someone could help me out.




LED UV x 20 - DC forward Voltage 3.4 - 3.8 Current 700mA
LED Cyan x 10 - DC forward Voltage 3.4 - 3.6 Current 700mA
LED Blue x 20 - DC Voltage 3.4 - 3.8 Current 700mA
LED Royal Blue x 20 Cree XT-E Current 1500mA
LED White x 20 Cree XT-E Voltage 3.2 - 3.6 Current 1500mA
LED RED x 10 - DC forward Voltage 2.7 - 3.0 Current 700mA




I was thinking to split each channel into 10 thus having 2 channels for UV,BLUE,ROYALBLUE and White. Thus having 10 Channels in all. I was thinking to use a 38v 10AMP PSU to run these.

Any Suggestions?

Thanks,
Kindest Regads,
Et