WEBENCH® Tools/WEBENCH-POWER-DESIGNER: Difference in results between WEBENCH flash and WEBENCH HTML5

AnBer,

Flash tools have been discontinued Jan 31, 2020. Can you please confirm if you are referring specifically to the designs in WEBENCH Power designer or any other tool like Filter Designer?

On over-sizing output filter: There should not be differences in designs on Flash and HTML unless the designs were generated at significantly different times or the input requirements including advanced options are not matching up (like switching frequency, current limit, etc.) There could be slight differences in costs of components that could affect the selection over different times but the calculations should be the same.

Phase/gain margin charts/opvals and design alerts: The gain/phase plots and operating values related to gain margin and phase margin should be available in the HTML tool already. Also, a design warning/alert should be issued for low phase margin if the device had the "Recompensation" feature enabled. Please share design with us so we can look at this further.

Please see screenshot below for your reference on how to share design:

Regards,

Amod

Hi TI team,

Here is the link of the simulated design based on a TPS543B20 on Webench Power Designer (Not Filter Designer):

webench.ti.com/.../SDP.cgi

I only change initially proposed self by another one (XAL6030-561MEB).

I'm pretty surpised by the number of 100uF decoupling ceramic capacitor at the output of the regulator (qty: 26).

Furthermore, Is the phase or gain margin values are available for this reglulator? I do not see any of these parameters on the given Operating Values

Thanks for your support.

Mickaël

Amod,

Also in attachment you will find a report from a WEBENCH FLASH (2017) for parameters that are slighly different.
You will see that the amount of output capacitors is much lower.
Can you please provide some inputs on the differences of results between WEBENCH FLASH (2017) and WEBENCH HTML5 (today)?
Vin_5V_Vout_0V9_15A_sim_old.pdf

A.

Mickaël, AnBer,

Thanks for sharing your design and pdf report. In conjunction with AnBer's pdf report, it seems the "Custom Output Specs" advanced option may not have been present in the tool in 2017 but it is recently added to the tool to allow for more customized designs. These specs are tighter than the initial default Cout spec parameters which might be one reason. In addition, "Ceramic" only output cap type option is another reason. One of our team members will look into the calculations and find out why for "Ceramic" cap type, we are needing 26 caps in parallel.

By the way, gain/phase charts and operating values are not modeled in the tool so these are not shown in the Charts or Operating Values sections.

Regards,

Amod

Hi Amod,

Could you please check as well the simulation results?

It seems that the "startup" simulation does not finish. The simulation plots for Vout and Iout are not showing stable/proper values:

Then when changing the default output cap to 3 caps (100uF/ESR=2.5mR) then results are better but the simulation plot still do not show the complete simulation.

-Could you please try both scenario?
-Could you check as well if the other simulation (load transient, ..etc) make sense?

Thanks in advance,

A.

Hi AnBer,

Cout selection is updated/corrected recently for TPS543B20 and will be available on ti.com by mid of next week. We have fixed the electrical simulations issue as well for startup, steady, line and load transient. Electrical simulation fix will take some time to reflect on ti.com (tentatively by first week of march). We will let you know once the fix is available.   

Best Regards,

Bhushan    

Hi AnBer,

Updated cout selection is now on ti.com. Please follow below steps to get lower quantity ceramic caps for your design. We will let you know once solution for electrical simulations is available on ti.com.  

1.  Create the design for your input case (Vin = 4.5-5.5, Vout= 0.92V, Iout = 12A, Ta = 85 decC) 

2. From configuration option, turn on custom output specs and change the Iout Trans Load step to 50%. Select the Ceramic from output cap options. Click on Redesign at the bottom after these changes.

3.Click on choose alternate for cout from schematic. 

4. Select the lower quantity cap from alternate list for your design.

Best Regards,

Bhushan

Hi Brushan,

Thanks!

How can we know that the different changes are online?
Are there release notes or alert for webench so that we know when modification/bug fixes are published online?

For the different SW packages we can setup alert from the my.ti.com but it does not seem to work for webench:

Hi Bhushan,

I have just quickly started a new design simulation on Webench and ouput capacitors sizing seems better than previously.

Thank you TI team for your support.

Mickaël.