WEBENCH-POWER-DESIGNER: How to add a specific core / coilFormer to webench power designer

Hi Flavio,

We can edit the parameters of the existing transformer. Following are the steps to edit the parameters.

Step 1: Click on the "Transformer" symbol in schematic.

Step 2: Click on "Off the shelf transformer".

Step 3: Click on "Edit" as shown in Image 1 below and provide the desired parameter values.

Step 4: Click on "Search with New Limits" as shown in Image 2 below.

Kindly revert back to us for any further queries.

                                                                                          Image 1

                                          Image 2

Thanks and Regards,

Umayal

Thanks Umayal,

unfortunately I haven't solved.
I specified the preliminary trasfo parameters got from a custom transformer designed by Wurth Elektronik as follow:

but when I press the "Search with new Limits" button and than SELECT:

an alert pops up, despite of decreasing the ambient temperature  or switching freq.:

So the simulation can't run.

How can I overcome the problem?

Here is the public link of the design :

https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=A97F79CCD7D5CBCE

Hi Flavio,

We are able to replicate the reported issue. We are working to resolve the issue and shall keep you updated on the status.

Thanks and Regards,

Umayal

Ok thanks. In the meanwhile, for the design above, how can I determine the primary inductance and turns fo a different core (ie EF20 with Ae=32mm2 and for an EF25 core with Ae=52.5mm2)? I tried to follow the design steps reported on par. 9.2.2 of the datasheet resulting in a turn ratio of 13 and primary turns less than 10 (precisely 6.2)! How is it possible? Is it available a specific calculus spreadsheet for this controller (or previous UCC28C40)? thanks.

Hi Flavio,

In regards to the query pertaining to primary inductance and turns for different core ,we have forwarded the query to our product expert.
Our experts will soon get back to you.

Thanks and Regards,

Umayal

Still no response from product expert.
Design questions such as:
- For the design for cost optimization of the simulation design above (no Optocoupler between Sec and Primary), which is the secondary side voltage regulation? How behaves the load regulation on 6V out?
- For the manual calculus of trasformer design with UCC28C50, I imposed the DCM mode DutyVinMin = 0.45 resulting in a Lp= 58uH @32Vin min and 176KHz Fsw.  Is it correct to consider a duty value less than 50%, as for any DCM mode flyback? Datasheet seems to consider higher values of duty@VinMin in any case.
- Can we finally have a design review of the circuit design?

Thanks in advance

fp

Hi Flavio,

We apologize for the inconvenience caused.
Our product experts are currently unavailable due to thanksgiving holiday.
Hence there is a delay in response.
We have forwarded the query pertaining to primary inductance ,turns and design questions to our experts.
We are following up on the same. We will keep you updated on this.

Thanks and Regards,
Umayal

Hi Umayal,

any news from product expert?.. still waiting.

Thanks
flavio

Hi Flavio,

We apologize for the inconvenience caused.

We have resolved the issue of alert pop up appearing when a custom transformer is created.

The changes are now in our internal servers. Will be available on ti.com by our next Webench release tentatively by mid of December.

We will keep you updated on the same.

For an immediate reference sharing the design report in below link.

link: /cfs-file/__key/communityserver-discussions-components-files/196/UCC28C50_2D00_Q1_2D00_Webench-Design-Report.pdf

In regards to below query,

“- For the design for cost optimization of the simulation design above (no Optocoupler between Sec and Primary), which is the secondary side voltage regulation? How behaves the load regulation on 6V out?”

In order to simulate the Webench design for Secondary side voltage regulation under “Configuration Options” kindly select “SSR” as shown in image 1 below and click on REDESIGN. 

Image 1

In regard to below query on design,

-Can we finally have a design review of the circuit design?

Could you please confirm in above point you are referring to which design for review?

For further assistance on following couple of queries pertaining to design, we are moving the post to product experts.

Query 1 from Flavio:

how can I determine the primary inductance and turns fo a different core (ie EF20 with Ae=32mm2 and for an EF25 core with Ae=52.5mm2)? I tried to follow the design steps reported on par. 9.2.2 of the datasheet resulting in a turn ratio of 13 and primary turns less than 10 (precisely 6.2)! How is it possible? Is it available a specific calculus spreadsheet for this controller (or previous UCC28C40)? 

Query 2 from Flavio:

For the manual calculus of transformer design with UCC28C50, I imposed the DCM mode DutyVinMin = 0.45 resulting in a Lp= 58uH @32Vin min and 176KHz Fsw.  Is it correct to consider a duty value less than 50%, as for any DCM mode flyback? Datasheet seems to consider higher values of duty@VinMin in any case.

Thanks and Regards,

Umayal

Thanks.
I need to compare the output volttage regulation between PSR (the chousen one) and SSR design.  I need some feedback from product expert about the PSR design as well, since it 's not possible to simulate it.

We designe a custom transofrmer with 6 secondaty outs and we have some doubts...

Thanks Steve,

just two notes about these:
Data sheet offers controllers with Dmax=50% for isolated topologies such as flyback and Dmax=100% for non-isolated topologies such as buck, boost
Since It's flyback on my case, and the Webench Design Tool has led me to select the UCC28C50 (duty max 100%)  for such flyback, should I consider the UCC26C51 (duty max 50%) part number instead? Or is it indifferent?

How about the output voltage regulation in PSR and SSR design?
We are designing with a custom Wurth transformer 750371769r00 Prelim Spec Sheet.pdf which has 6 secondary winding and for cost reasons we would like not to use a secondary side opto, so a PSR design as the one attached. Main output (the one with the highest current dynamics) will be Sec1, the others (Sec2 to Sec6) will deliver roughly a costant corrent/output power. All outputs will be post regualted via LDOs however. 
Can we assume that the attached Webench designWBDesign8_PSR_NoOpto.pdf is also valid for such custom transformer?
regards

Flavio