Tool/software: Webench
I am working with TPS54202 and I have question about the minimum value of the output inductor .
Design inputs: VinMin=14V, VinMax=24V, Vout=7.3V, Iout=1.0A
With WEBENCH® Designer TPS54202 program calculate inductor value L=6.8uH.
Eguation 8 in Data Sheet TPS54202 recommend inductor value Lmin=34uH.
Help please select target value output inductor. Thank you!
Hi Vasilij,
The equation in the datasheet corresponds to inductor selection with a ripple percentage, Kind of 0.3.
However Kind can be chosen differently depending on your application.
You can see the limits proposed by WEBENCH for inductor selection (in this case it is from 6.8 u – 50 uH) by clicking on the inductor in the schematic and then press “Select Alternate Component” button.
With a 6.8 uH inductor, your Kind will be ~1.5, pk-pk ripple ~1.5*1 = 1.5 A
Peak current will go up to 1+0.75 = 1.75 A
In case of using 34 uH inductor, Kind ~0.3, pk-pk ripple ~0.3*1 = 0.3 A
Peak current will go up to 1+0.15 = 1.15 A
You can go with any of the values of inductor above depending on your requirement/peak currents. WEBENCH picks up an inductor value in the schematic based on number of constraints like cost, footprint, etc
To see the range of inductor values that can be used, it would be better to refer to the above “Select Alternate Component” window, and then deciding which one to go for.
Let me know for any question.
Thanks
sahil
