LED driver Feedback line diode

Thread Starter

s34n

Joined Jan 1, 2024
19
Got a LED driver circuit with a resistor and diode in parrallel on the feedback line, just wondering what the diode is for?

XLSemi XL6005E1

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Cheers
 

Thread Starter

s34n

Joined Jan 1, 2024
19
This circuit board has pin 2 left floating for a "default high" as far as I can tell by the data sheet.
I'm not sure the diode is for PWM in this case. But I dont know.
 

ronsimpson

Joined Oct 7, 2019
3,131
The IC boosts the volage up. If the diode fails open. (broken wire or LED not soldered well) The voltage will get very very high. The output capacitors may fail. The supply diode may fail and the IC probably will fail. The simple answer is to add a Zener diode that, under overvoltage conditions, will pull up on the FB pin.

The circuit will work just fine without the Zener diode.
 
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