WEBENCH® Tools: Flyback transformer given in the web bench cannot be manufactured because the specifications are not enough

Hi Karthikeyan,

We have forwarded the query to our experts.Our experts will get back to you soon.

Thanks and Regards,

Umayal

Hi Karthik, 

Thanks for the feedback. WEBENCH transformer designer gives comprehensive information of the transformer design including core/bobbin selection with Np, Ns. Naux with the corresponding layers/strands and AWG required. However for this particular operating condition, the transformer design is not able to be made by the software.

From what I see,  the reason is - this is high current condition, where the RMS currents are higher. WEBENCH designer algorithm designs the transformer taking into consideration several factors: maximum permissible power loss, maximum number of feasible layers, strands, etc. For this particular condition it could not achieve the design with available core/bobbin database, hence it gave only the limited information.  

Let me still see if it is possible to create the transformer design by modifying some parameters/adding some additional core/bobbin, I will update you. 

Thanks

sahil

Hi Karthik, 

I checked it, WEBENCH uses TIS(triple insulated secondary) for the transformer design for the sec winding, For this particular operating condition, the current is pretty high for fly-back, hence it cannot create the transformer design with TIS fulfilling the winding width fill, lesser strands, etc. 

We might have to go for foil winding for this particular transformer design. The algorithm currently only supports TIS for secondary and heavy insulated magnet wire for primary and auxiliary. I will add this for future addition (foil winding support for high current outputs), for now it might not give the transformer details. 

Let me know if anything else here. 

Thanks

sahil

Thanks for the reply. Is there any other solution?.  

My requirements are

Input 24VDC

1. 12VDC @ 8AMP

2. 5VDC@8AMP

3. 3.3VDC@8AMP

All this DC to DC converter for the automotive application.

Most of my projects are based on TI.

Hi Karthik, 

I am assuming the above 3 are separate power supplies. It might be good to for forward topology instead as output currents are high. 

I found two reference designs at TI for 12V@8A, - PMP5123 and PMP5549. They use UCC2897A in active clamp forward configuration, the complete schematic and BOM with test results. Let me know if that helps. For other outputs 5V@8A or 3.3V@8A , we might have to modify the 12V circuit. 

https://www.ti.com/tool/PMP5123?keyMatch=PMP5123&tisearch=Search-EN-everything&usecase=GPN

https://www.ti.com/tool/PMP5549?keyMatch=PMP5549&tisearch=Search-EN-everything&usecase=GPN

sahil