Need help for output voltage of switching regulator

[hfc1993911hfc]

Net 'Vout" connects to the output end of a switching regulator(called LM3478). Net 'FB' connects to the FB pin of LM3478. as you known ,the FB pin will always be 1.26V in refer to the ground and the voltage between the cathode and the node is always 2.5V. Now i want to figure out the range of the 'vout' through adjusting the
potentiometer and how you make it out. can you type in detail?

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This is the schematic ,I am in a hurry. Thank you very much .

 

[hfc1993911hfc]

i am sorry that i made a mistake above. what i want to know is the range of current across the LED rather than the range of 'Vout'.

 

[hfc1993911hfc]

It seems that nobody can answer my question, I am so sad. wu wu wu……

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It seems that nobody can answer my question, I am so sad. wu wu wu……

 

[KlausST]

Hi,

what idea is behind that circuit?
How should it work?

The max. VOut depends on: Iled, Vin of regualtor, Vdrop of regualtor, Rdc of inductor, R10...

Klaus