• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 615 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TPS54335A/about inductor selection

Tsukui Yusuke
Guru 21930 points
Other Parts Discussed in Thread: TPS54335A

Hi,

Could you tell me about TPS54335A inductor selection?
About the Lmin calculate , from the datasheet it is calculate as follows:


 

About the Iout parameter, did it mean the normal operation current ?

Or it is means the maximum current?

For example, in the follows design, the 12.4V maximum current is 790mA,

But the normal operation current is only 48.7mA,if we use the 48.7mA for Iout

,the inductor should be at least 356Uh,I think it is not right.

Could you tell me your advice?

Best regards,
Yusuke/Japan Disty

  • 0
    TI__Guru**** 191445 points
    You typically want to have the inductor ILp-p be 20 to 40% of the nominal output current. So yes if you use a 3 A part to supply 48.7 mA, you will calculate a very large inductor value. For synchronous converters it is not such an issue to use a smaller inductor value. For non synchronous devices, small inductor will force DCM all the time. For TPS54335A it may affect the eco-mode threshold. Also higher switching ripple current will increase losses and lower efficiency. But larger inductor value will have higher DCR (unless you use a physically very large inductor). So it basically is up to you. How much peak switch ripple current do you want in your design?