ground question in powersupply

[aliyesami]

hi I am using meanwell LDD 700H driver and iam confused on how to ground the output
i ground the input pin but I do not connect the output ground to input ground , should i connect those together?

the datasheet of LDD700H is https://pdf1.alldatasheet.com/datasheet-pdf/view/424110/MEANWELL/LDD-700H.html

please see the attached schematics

 

[barry]

For -Vin it says, RIGHT THERE ON THE DATA SHEET, , "don't connect to -Vout". I guess that means you shouldn't connect them together. Further, why do you even think you need to "ground the output"? You're driving an LED; connect one side of the LED to +Vout, connect the other side to -Vout. Done.

 

[aliyesami]

For -Vin it says, RIGHT THERE ON THE DATA SHEET, , "don't connect to -Vout". I guess that means you shouldn't connect them together. Further, why do you even think you need to "ground the output"? You're driving an LED; connect one side of the LED to +Vout, connect the other side to -Vout. Done.

then on pcb layout how will i lay my ground layer? will i have two ground layers ? one for 50V and one for 3.3v and 12v ?

 

[barry]

Upon closer examination, I realize I have no idea what you are trying do. The LDD700 is a constant- current led driver that you have hooked up to some unidentified device, perhaps a regulator? WHAT IS GOING ON HERE?

 

[aliyesami]

its a very simple working device. . LDD700H is fed 50v , and the output is driving two LDO's one producing 12v and one producing 3.3v

 

[barry]

its a very simple working device. . LDD700H is fed 50v , and the output is driving two LDO's one producing 12v and one producing 3.3v

And what is the output LDD700? It's a constant current. I think you want a DC-DC VOLTAGE converter, not an LED driver. Or, better yet, why don't you just use two switching regulators?