WEBENCH® Tools: How to set a Isolated DC DC converter with multiple isolated outputs in TI webench power architect

Aneesh TS

Expert 1735 points

Other Parts Discussed in Thread: PMP40274, PMP4468, PMP11107

Tool/software: WEBENCH® Design Tools

Dear all,

I have a requirement of a DC DC converter with following specification

Input voltage 18V to 36V

Output1= 3.3V/7.5A

Output2= 1.5V/3A

Input to output isolation required and both outputs(3.3 and 1.5) should be isolated each other.

I am facing problem in giving the isolation requirement. How to specify this isolation requirement in TI Webench power architecture?

Regards

Aneesh

over 5 years ago

0 Umayal Ramanathan over 5 years ago

TI__Expert 5040 points

Hi Aneesh,

Currently there doesn't seem to have an isolation requirement in TI Webench power architect tool , we shall get in touch with our experts and get back to you.

Thanks and Regards,
Umayal

0 Aneesh TS over 5 years ago in reply to Umayal Ramanathan

Expert 1735 points

Dear Umayal,

Kindly suggest if TI is having any reference design which meets my requirement.

Regards
Aneesh

0 Robert Taylor1 over 5 years ago in reply to Aneesh TS

TI__Expert 5745 points

Hi Aneesh,

I could not find a design that exactly meets your specifications, but I found a few that might get you started.

Vin = 18V to 36V, Output Power ~30W

PMP40274 is a synchronous flyback (5V/6A), but with a transformer redesign you could make 2 outputs

PMP4468 is an Active Clamp Forward, this design could also be made to have 2 outputs.

The choice of flyback or forward is really up to the specificiations. The flyback might be lower cost, the ACF will have better efficiency and noise performance.

PMP11107 shows a dual output flyback.

While none of these are exact, hopefully they help get you started.

Thanks,

Robert

0 Aneesh TS over 5 years ago in reply to Robert Taylor1

Expert 1735 points

Hello Robert,

Thanks for sharing the details.

I got PMP10871 from TI which is having very small footprint. Looks like it is more suitable.

Main output winding i can use for 3.3V/7.5A with transformer Re-deign. But need to add second winding for the transformer for 1.5V.

But my doubt is what will be the regulation in second output, since only first output will be regulated through feedback ?.

Regards
Aneesh

0 Robert Taylor1 over 5 years ago in reply to Aneesh TS

TI__Expert 5745 points

Hi Aneesh,

I think you can expect to get 10% regulation on the winding that is not regulated. But this is a function of the transformer design.

Thanks,

Robert

0 Aneesh TS over 5 years ago in reply to Robert Taylor1

Expert 1735 points

Hello Robert,

Thanks for your reply.

I think compared to forward converter flyback converter will be having more voltage variations right?.
And double ended topologies such as Push pull, Half bridge and full bridge topologies will be having less voltage variations compared to forward converter .
Please correct me if i am wrong.

Regards
Aneesh

0 Robert Taylor1 over 5 years ago in reply to Aneesh TS

TI__Expert 5745 points

Hi Aneesh,

Again it really depends on the transformer construction. There is no general rule that says one will be better than the others.

Thanks,

Robert

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WEBENCH® Tools: How to set a Isolated DC DC converter with multiple isolated outputs in TI webench power architect