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LM5164: Why is inductur current rating so high?

Part Number: LM5164

Hello,

I am evaluating the buck converter LM5164DDAR in your WEBENCH online tool.

Following my requirements:

Vin = 10.5 V - 80 V

Vout = 10V

Iout,max = 0.3A

Tambient = 100°C

Attached the exported WEBWECH report.

8726.Report.pdf

Trying to change L1 ( that is very expensive ),  the WEBENCH recommends to use inductors with IDC between 2.514 A and  50.29 A.

Why is this current rating so high? The simulation indicates that IInductor never exceeds 360mA.

Regards,

Lorenzo

  • Previous report includes a 48V Vin simulation, the following an 80V Vin simulation:

    Report_80V.pdf

    IInductor peak is always below 370mA.

    Why is inductor current rating so high?

    Regards,

    Lorenzo

  • Hi Lorenzo,

    I agree, the inductor is larger than needed. My guess is that the inductor returned in Webench was the only one in their library that matched the inductance value and saturation current level. The saturation level should be higher than the current limit setting of the device.

    Follow the inductor equations in the datasheet to make sure the inductor meets your design requirements.

    Regards, Jason