• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 84 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.

LM5158: Inrush current when start up

Rannie Zhou
Expert 4120 points
Part Number: LM5158

Tool/software:

Hi team,

my customer used LM5158 and find that there is an inrush current within a few ms after EN is turned on (but the actual TSS setting is several hundred ms), and the Vout suddenly has a voltage of more than 10V (the voltage design is 60V). Logically, it should be started according to TSS. Can you help me confirm what is going on?

Vout:

SS: you can see there is a drop on SS, and there is a 400mV voltage on SS pin before drop.

Sch: note: R431 on SS is shorted.

BRs,

Rannie

  • 0
    TI__Expert 4090 points

    Hi Rannie,

    Thanks for using the E2E forum.

    Can you please specify the supply voltage of your converter and the complete schematic of your design?

    In boost topology, the output voltage should be equal to the input voltage when device is not turn on.

    Once the voltage at VCC is above the Vcc-uvlo threshold then the soft start cap start charging, but before it, the device is not switching. 

    Best Regards,

    Hassan