TPS23753A: To improve thermal performance

Michael Jeong1

Expert 2600 points

Part Number: TPS23753A
Other Parts Discussed in Thread: UCC28780EVM-002, UCC24612-1EVM

Hello Expert,

Our customer has thermal issue on their b'd and they are using tps23753a.

Their application is IP Network Camera.

The heavy thermal points are Q1, Q2, T1 on the schematic.

So they want to improve thermal performance on the schematic or get another recommended parts (ex, PD, FET, Some point to improve it, etc).

Could you please review and guide?

* Schematic

Best Regards,

Michael

over 3 years ago

0 Michael Pahl over 3 years ago

TI__Mastermind 21320 points

Hello,

The thermal performance of Q1, Q2 and T1 have nothing to do with the PD.

The sources of thermal problems are typically: layout, packaging, voltage/power stress.

Check the Vds of the MOSFETs to see if there is a high overshoot. This can lead to poor thermals.

If all these components are having thermal issues, they may not have enough copper in the layout.

If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

Regards,

Michael P.

Applications Engineer

Texas Instruments

0 Michael Jeong1 over 3 years ago in reply to Michael Pahl

Expert 2600 points

Hi Michael,

I'm considering Synchronous rectifier (SR) controllers to improve efficiency on 2'nd side.

Is it possible to control MOSFET w/ SR on TPS23753A?

For your information, below is EVM.

UCC28780EVM-002 : https://www.ti.com/lit/ug/sluubo8a/sluubo8a.pdf?ts=1624416977827&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FUCC28780EVM-002

UCC24612-1EVM : https://www.ti.com/lit/ug/sluubp3/sluubp3.pdf?ts=1624431025632&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUCC24612

If you have a reference or some guidance, could you please let me know?

BR,

Michael

0 Michael Pahl over 3 years ago in reply to Michael Jeong1

TI__Mastermind 21320 points

Hey Michael,

Either one of these controllers seems fine to me to use as a secondary gate drive.

Using a gate drive on the secondary is independent of the PoE PD + PWM controller.

Please refer to this blog post about the different types of flybacks: https://e2e.ti.com/blogs_/b/powerhouse/posts/maximizing-poe-pd-efficiency-on-a-budget

You might be able to get another 1% or 2% from using a synchronous gate drive/