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LP8863-Q1: Output voltage maximum with external power supply.

A Bokma
Prodigy 125 points
Part Number: LP8863-Q1


Dear mr, mrs, 

I want to use the LP8863 but need also a (little) higher output voltage then the 47V. It should be 53V. 

Is it possible to use an external power supply at 53V and set the LED_EXT_SUPPLY bit?

As the application is for a multiple led control with all kind off different led configurations this IC is right for 90% of the applications. 


Thanks,

  • 0
    TI__Expert 5475 points
    Hi,

    Actually the main limitation of the maximum output voltage is the maximum voltage rating of the LEDx pins, no matter using external power supply or using boost output voltage to drive the LEDs. If the current sink channels are disabled, with small leakage current , the voltage drop on the LED string is small. So the voltage stress will be applied on the LEDx pins.
    One way to increase the maximum output voltage is to add external 10Mohm resistor at each LEDx pins to increase the voltage drop on the LEDs, so that the voltage on the LEDx pins can be reduced.
  • 0 in reply to Shirley He
    Prodigy 125 points

    Hi Shirley, 

    Thanks, this is even better then thought. I will test it.