TPS552882: inductor current limit and Webench selection

Lenio Cacula

Part Number: TPS552882

I designed a circuit for TPS55282 using Webench, 12Vin, 12Vout, Iout=3A. Webench uses a current limit of 15A with a 21kΩ connected to ILIM pin, yet the inductor selected in the BOM saturates at 13A. The inductor is not protected in case of an overcurrent. If I change the design to lower currents, 1A for instance, the different is even greater. Based on the formula in the datasheet, the ILIM resistor should be greater than 27kΩ. Can you please comment on that observation? Should I ignore Webench and use a larger resistor at ILIM?

Thank you!

over 3 years ago

0 Zack Liu over 3 years ago

TI__Mastermind 34231 points

Hi Lenio,

May I know the application worst condition, like minimum Vin, maximum Vin? The inductor average current limit needs to be designed at worst condition.

I agree to change the current limit lower to protect the inductor.

0 Lenio Cacula over 3 years ago in reply to Zack Liu

TI__Genius 16700 points

Input is within ±10%.

+1 Zack Liu over 3 years ago in reply to Lenio Cacula

TI__Mastermind 34231 points

Hi Lenio,

For this 12Vin, +-10% tolerance, 12Vout, Iout=3A application, the inductor average current limit could be set to ~5-6A. The ILIM resistance could be set to 330000/6A=55kohm.

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TPS552882: inductor current limit and Webench selection