• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 64 subscribers
  • Views 789 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.

LP8863-Q1: LP8863-Q1 softstart sequence

Tomohiro Nagasawa58
Expert 1570 points
Part Number: LP8863-Q1

Dear support team

Could you provide softstart sequence picture?

It will be helpful if you can give an explanation about behavior.

Regards

Tomohiro Nagasawa

  • 0
    TI__Intellectual 2140 points
    Thank you for your inquiry. Please allow a little time for us to provide the inforation you requested.
  • 0 in reply to Angelos Tsiros
    TI__Expert 4565 points

    Hi,

    Please refer to Figure 28 on datasheet.

    With all power rails up(VDD, VIN, VDDIO), Vout will ramp up with EN high(using power line FET) from ground level until Vin level, and will stay at Vin level for 50ms. This is to reduce initial inrush current to fill output caps. Then, Vout continues ramping until initial voltage level(47V typ with 910kohm and 100kohm FB divider resistors). After 50ms from this Vout ramping, LED driver will be enabled.

    tsoftstart is power line FET soft start to lower inrush current, and tstartup is time from boost ramp to LED driver enable.

    Hope this helps,