LP8868U-Q1: LP8868-Q1

akanksha upadhyay

Part Number: LP8868U-Q1

Tool/software:

Dear Sir,

I am using LP8868-Q1 IC as LED Driver, and is working on its compensation circuit. I have set led current as 820mA and have used 33uH inductor .

But while giving pwm at pwm pin of IC with its frequency 5KHZ, at duty below 98% i am hearing a noise from inductor . How to set the compensation circuit in order to get rid of this

sound and to what extent can i reduce it .

Thanks & Regards

Akanksha

5 days ago

0 Suchen Dong 5 days ago

TI__Expert 3211 points

Hi Akanksha,

Could you share the schematic and key waveform (like the output LED current waveform)?

Best regards,

Suchen

0 akanksha upadhyay 5 days ago in reply to Suchen Dong

Prodigy 100 points

Led Waveform is not noisy and is OK , is there any another method apart from tuning through hit and trial method

0 Suchen Dong 5 days ago in reply to akanksha upadhyay

TI__Expert 3211 points

Hi Akanksha,

For a 5kHz dimming frequency. It could be an audible noise for the frequency is under 20kHz. That's why we need more information to find if there's anything to improve.

If you find the LED current is good. It's better to check the inductor waveform.

Typically, decrease the Rcomp and increase the Ccomp can slow down the loop response, which is may helpful.

Best regards,

Suchen

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LP8868U-Q1: LP8868-Q1