Tool/software: WEBENCH® Design Tools
Hello,
I am creating a design with LM5175 for a USB-C PD supply with 3S battery backup, but mainly it uses a 150W 24V DC power supply. So my design has the following initial parameters:
Vin: 11V-24V
Vout: 5V/5A, 9V/5A, 15V/5A, 20V/5A
As per equation (15) [page 22] from the datasheet, the max average inductor current occurs at maximum load and minimal input voltage, which produces 10A at 20V/5A output and 11V input. The peak inductor current follows from equation (16) and is 12.5A. This sounds reasonable...
But I tried to verify my design in WEBENCH and got a value for peak switching current of 32.5A! First of all, I am unable to find a formula for this in the LM5175 datasheet. Secondly, where (which node?) does this peak switching current appear and when - also not enough information in the datasheet? Is this a problem with WEBENCH which I should disregard, or is there a problem with my components/values selection which I should address? I have attached the WEBENCH report and you can find this issue as item #72 in the Operating Values section.
I would appreciate some help with this, thanks in advance!
Best regards,
Todor
