LP8860-Q1: screem flicker phenomenon

Qianqian

Genius 5010 points

Part Number: LP8860-Q1

Hello TI Experts,

Now I am using LP8860A, and I meet with a problem needs your suggestion：

When the boost_freq_sel is set to 001(303khz),input voltage below 10V, the screem will flicker , over current protect~

When the boost_freq_sel is set to 101(800khz) everything is ok, their is no OVP or flicker phenomenon~

I wonder why I cannot use the default value of boost_freq_sel 303KHz？

over 6 years ago

0 Shirley He over 6 years ago

TI__Expert 5475 points

Hi ,

Did you trigger the maximum current limit for boost SW mode? What is the maximum current setting of BOOST_IMAX_SEL[2:0]? If switching frequency is lower, the current ripple will be higher. So if the current limit is very marginal at 800kHz, it may trigger the current limit at lower frequency.

0 Qianqian over 6 years ago in reply to Shirley He

Genius 5010 points

Hi Shieley,
Thank you very much for your help~
BOOST_IMAX_SEL[2:0] is set to 011 ,which means maximum current is 9A
So if I want to use 303khz, what should I need to change?

0 Shirley He over 6 years ago in reply to Qianqian

TI__Expert 5475 points

Hi,

9A seems high enough. I'm not sure if maximum current limit is triggered. What is the calculated peak switching current when input voltage is 10V and switching frequency is 303kHz?

0 Shirley He over 6 years ago in reply to Shirley He

TI__Expert 5475 points

Hi,

I'll close this thread due to inactivity. If you have more questions, just reply to it directly and it will open again. Thanks a lot.

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LP8860-Q1: screem flicker phenomenon