TPS54340: Compensation circuit results on Webench differ significantly from results using datasheet equations

Hi Falk,

Thank you for posting. Allow me some time to investigate this.  At the same time, could you check your Webench input parameters?  I have checked that to generate 10V the Rhs=130k while Rls=11.3k.  However, in your model, Rhs=243k, which leads to regulator at 18V instead of 10V. 

Thanks,

Youhao

Sorry Youhao, I've made a type. The output voltage target is 18V, not 10V.

Thank you for the clarification. I will investigate this and get back to you in the next couple of days. 

Hi Falk,

I used both the datasheet equations, the design calculator and the Webench model, and found the calculator and datasheet equations are aligned, and the Webench model is different.  I will ask our Webench group to take a look.

Thanks,

Youhao

Thank you Youhao. I look forward to hear back which tool I should follow. Much thanks indeed.

Hi Shaheen,

thank you for your response. I still find it strange that the minimum and maximum component value offered by the Webench tool doesn't even include the calculated value from the data sheet equations for one of the components. I used Webench to simulate with a few values and I am moving forward on this circuit - so we can close this conversation. Thank you. 

Hi Falk,

I have a similar concern but for UCC28950.

In your implementation did you use the Webench values as a starting point or the datasheet calculations? Any difference?

Thanks

Hi Brian, I ended up going with values closer to the webench results. We have a design in production for a long time that seems to be similar to that compensation circuit.