• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 432 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

WEBENCH® Tools/LM5176: What is the maximum value of soft start capacitor to get maximum soft start time?

Andrey Yakimov
Prodigy 190 points
Part Number: LM5176

Tool/software: WEBENCH® Design Tools

Hi Team,

I'm developing lead battery and supercapacitor charging device based on LM5176.

9-15V VIN   …..  0-15V 9A OUT CCM - mode; DITHERING - disable; NO BIAS supply; Frequency 250 KHz.

To avoid large sparking during handle battery connection I need very soft start.

What is the maximum value of soft start capacitor to get maximum soft start time?

Is it OK to use 22uF X7R capacitor to get Tss = 22uF*0.8V / 5uS = 3.5 Sek ?

Thanks!

  • 0
    TI__Guru* 78440 points
    Theoretically there is no limit on the capacitor value. However, a very large capacitor may have large leakage current, and the LM5176's SS current source is about 5uA. So, pay attention to the capacitor leakage spec and make sure it is not greater than 5uA, or you are not able to start up.