WEBENCH® Tools/TPS54302: TPS54302 - choice of inductor

Laszlo Gaspar

Part Number: TPS54302

Tool/software: WEBENCH® Design Tools

The choice of inductor for the TPS54302 is confusing.

The evaluation board is set to produce a 5 Volt output from an 8 Volt to 28 Volt input and uses a 10 uH inductor. But if I enter my design requirements (15V input voltage, 0.5 Amp output current), WEBENCH gives me a choice of inductors between about 6 uH and 9 uH and tells me that 10 uH is too large for this design.

So, to cut through the confusion: assuming my requirements (15V input voltage, 0.5 Amp output current), what would be the recommended value for the inductor?

over 6 years ago

0 Shawn Nie over 6 years ago

TI__Genius 10070 points

Hi,

If you set VIN from 8V to 28V, the inductor should be cover the whole range of input voltage.

For the 15V input voltage, I think 6.8uH or 10uH are okay.

Shawn

0 Shawn Nie over 6 years ago in reply to Shawn Nie

TI__Genius 10070 points

Hi,

Do you have any other question?

Shawn

0 Laszlo Gaspar over 6 years ago in reply to Shawn Nie

Prodigy 30 points

I tried different inductors and - at least with my relatively light 200 mA load conditions and at 15 Volt input voltage - I measured slightly better (89%) efficiency with 10uH (evaluation board) than with 5.6 uH (WebBench recommended value) (88%).

So it's no big deal, although I think the fact that the data sheet and the evaluation board recommend 10uH while WebBench tells you that 10uH is too large and falls outside the range is quite confusing. So in this sense WebBench is not very helpful. Oh, I just wish things could be simpler.

0 Shawn Nie over 6 years ago in reply to Laszlo Gaspar

TI__Genius 10070 points

Hi,

I checked the Webench model, there is no issue like you said.

Anyway, you can refer to datasheet "8.2.3.5.1 Inductor Selection" to calculate the value of inductor.

Shawn

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WEBENCH® Tools/TPS54302: TPS54302 - choice of inductor