LM5141QRGEVM: Soft start problems

Frank QIN

Part Number: LM5141QRGEVM

Hi team,

I'd like to figure out the soft start working pattern, and I'm using the evaluation module.

-Is there any other element effect on the soft start time or behavior except the soft start capacitor Css? How?

-According to the datasheet, soft start shows different result due to low-side MOS between FPWM and DEMB mode. So is there gonna be different if I change the resisters at HO/LO?

-When SS pin turns low voltage, is it because of load changing and current excess the limit? Does it needs soft start again?

Many thanks

Best,

Frank

over 5 years ago

0 Daniel Li14 over 5 years ago

TI__Mastermind 27470 points

low side mosfet behavior is different in FPWM and DEMB, but it won't affect the soft start time unless you have too large output cap with heavy loading, it may hit the overcurrent , then softstart voltage will come to 0. you can also check RES cap voltage see whether it raise up to 1.2V

Thanks

0 Frank QIN over 5 years ago in reply to Daniel Li14

TI__Expert 8910 points

Hello Daniel,

Thanks for your reply and suggestion.

Best,

Frank

Power management

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LM5141QRGEVM: Soft start problems