WEBENCH® Tools/LM5175: LM5175PWPR

Hi Nidhi,

I was able to get the same mosfets as shared design report (selected from alternate components). Please find the attached report and Webench design below.

Report: /cfs-file/__key/communityserver-discussions-components-files/234/WBDesign8667.pdf

Webench Design:   https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=79D02EB7AE291445

Thanks for sharing the calculations xls as well. I am looking into the calculations and will be back with my observations.

Best Regards,

Bhushan

Hello Bhushan,

Thank you I wasn't able to do that. Please can you let me know about the calculations

Sure NIdhi,

I will go through the calculations early this week. Could you please try below excel calculator for your calculations as well (attached)? Let me know.

Excel calculator: /cfs-file/__key/communityserver-discussions-components-files/234/snvc181c.zip

We can download the same from below product folder link. 

Product folder link : https://www.ti.com/product/LM5175

Best Regards,

Bhushan

Yes this is in accordance to my calculation but it is not the same as we bench.

So how does one account for parallel mosfets I am attaching calculations which are far different from the schematic generated by we bench

LM5175 Buck-Boost Quickstart Tool -- r9.rar

Hi Nidhi,

I verified few Webench calculations with respect to excel calculator. Please find my observations below.

1. Feedback resistors, Inductor, Soft start cap, Rt resistor calculations seems be correct.

2. Rsense you can use from the excel calculator 9.8mOhm. Please make sure to change Cslope cap as well according to Rsense (Cslope would be = 62 pF).

Webench has a complex mosfet selection which accounts for many factors while selection (junction temperature of mosfets should not exceed, ratings should match worst case voltage and current seen by Mofets etc..). This will be difficult to put it in sheet and match. I will suggest to try Webench suggested mosfets (with quantity) for your case. Please let us know if you have further queries on mosfet selection. Hope this helps.

Best Regards,

Bhushan 

Hello Bhushan,

Thanks for the update. What about the compensation components?

Hi Nidhi,

As compensation is dependent on Rsense and we are using Rsense value from excel sheet, we should use Ccomp, Comp2, Rcomp from from sheet as well. Make sure you we are using same Inductor and capacitor(cout) value in sheet as same as that of Webench to get the values of compensation.

Best Regards,

Bhushan 

As per my understanding all the passives values should be considered from the sheet(as attached) . While mosfet selection is from WEBench?8420.LM5175 Buck-Boost Quickstart Tool -- r9.rar