LP5569: LED Forward Voltage

Simone Calo

Part Number: LP5569

Hi! I was considering using LP5569 to drive 3 separate segments of a 12V RGB LED strip (each segment has 3 LEDs in series for each color). Can external 12V be used to power ONLY the LEDs as long as the currents flowing into the driver are kept within specs? Something like what is shown in the picture attached.

Thanks

11 months ago

0 Jared Zhou 11 months ago

TI__Genius 13640 points

Hi Simone,

I don't think this is allowed since the maximum voltage that the output can withstand is only 6V. If you use 12 as the external LED input, the voltage dropped on the output could be burned it.

BR, Jared

0 Simone Calo 11 months ago in reply to Jared Zhou

Prodigy 10 points

Hi Jared,

considering a voltage drop over a series of 3 LEDs with a Vf = 3V each, the voltage measured at the output pin of the IC shouldn't be higher than 6V, right? Am I missing something here?

Thanks

Simone

0 Jared Zhou 11 months ago in reply to Simone Calo

TI__Genius 13640 points

Hi Simone,

Yes, it's correct but not enough. Since the LED could be short-circuited, so to be on the safe side, we always recommend the max VLED should not over the maximum voltage of output pin.

BR, Jared

0 Simone Calo 11 months ago in reply to Jared Zhou

Prodigy 10 points

Ok, thanks for clarifying this Jared!

0 Jared Zhou 11 months ago in reply to Simone Calo

TI__Genius 13640 points

Hi Simone,

Nice to help you!

BR, Jared

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LP5569: LED Forward Voltage