TPS23753A: TPS23753A

Jamie Tseng

Part Number: TPS23753A

Hi Team,

Could you kindly help review theschematic:

Sames case have posted before: https://e2e.ti.com/support/power-management/f/power-management-forum/964192/tps23753a-no-output-5v?tisearch=e2e-sitesearch&keymatch=TPS23753A

But we are not sure if diode is D3 metioned in "

Also we do not recommend diode flyback for 5V - we recommend sync flyback."

Please help check the laetest schematice.

Thanks and best regards,

Jamie

over 4 years ago

0 Michael Pahl over 4 years ago

TI__Mastermind 21320 points

Jamie,

Yes it si D3 that makes it a sync flyback. Please see the following post about the different types of flybacks.

https://e2e.ti.com/blogs_/b/powerhouse/posts/maximizing-poe-pd-efficiency-on-a-budget

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 Jamie Tseng over 4 years ago in reply to Michael Pahl

TI__Intellectual 2405 points

Hi Michael,

Do you have any comment about the schematic?

Thanks and best regards,

Jamie

0 Michael Pahl over 4 years ago in reply to Jamie Tseng

TI__Mastermind 21320 points

Jamie,

My comment is that we do not recommend this topology for this output voltage. Please change the topology.

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 Simon yu over 4 years ago

Prodigy 55 points

Hi Michael,

Could you comment more detail that you do not recommend this topology for this output voltage about the schematic?

thank you

0 Tommy Tzeng over 4 years ago in reply to Michael Pahl

Genius 5690 points

Hi Michael,

may i know why ti TPS23753AEVM-001 evaluation board is diode flyback for +5v? instead of sync flyback, thanks for your help.

0 Michael Pahl over 4 years ago in reply to Simon yu

TI__Mastermind 21320 points

Simon,

Poor regulation and poor efficiency.

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 Pahl over 4 years ago in reply to Tommy Tzeng

TI__Mastermind 21320 points

Tommy,

That design was created 7 years ago. You can see that the 48V PoE efficiency barely touches 80%. I do not know of an application that would accept such a low efficiency rate. If it is truly a cost difference, most people look at bucks instead.

You can note it is the first and last of its kind.

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 Simon yu over 4 years ago in reply to Michael Pahl

Prodigy 55 points

Hi Michael,

I have refers to the TPS23753AEVM-235 reference design, and modify the schematic for sync flyback,

I have one question that TPS23753AEVM-235 is designed for CLASS 3, Can i use the design applicable to CLASS 0? And do you have any comment about the schematic?

https://drive.google.com/file/d/1rNpqc2Ql_yB-Vk0EcZ7bm_VV7lbk_IY_/view?usp=sharing

thank you

0 Michael Pahl over 4 years ago in reply to Simon yu

TI__Mastermind 21320 points

Hey Simon,

Due to access restrictions and precautions, I cannot access a file sharing site like google drive. TPS23753EVM-235 is a good design to follow. If you tell me what components are different I can tell you the impact.

Or you can send me the schematic in private messenger.

Class 0 and Class 3 are both 13W of power. Class 0 represents a legacy class that goes before the IEEE802.3.af (2002) standard. A PSE will send 13W of power either way.

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 Simon yu over 4 years ago in reply to Michael Pahl

Prodigy 55 points

HI Michael,

I had sent the friendship request , Could I friend you on messenger?

Thank You

0 Michael Pahl over 4 years ago in reply to Simon yu

TI__Mastermind 21320 points

Simon.

Yes.

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 Simon yu over 4 years ago in reply to Michael Pahl

Prodigy 55 points

HI Michael,

I can't use messenger sent message to you , Can you confirm my friendship request?

thank you

0 Simon yu over 4 years ago in reply to Michael Pahl

Prodigy 55 points

HI Michael ,

1.I have refers to the TPS23753AEVM-235 reference design , and modified the schematic as below, (the same as reference design, but i know some parts are EOL)

2.Others design are the same as below schematic, Do you have any comment about the schematic?(I still can't sent schematic to you in private messenger. )

/cfs-file/__key/communityserver-discussions-components-files/196/GMI_5F00_TPS23753APW_5F00_POE_5F00_PD.pdf

thank you

0 Michael Pahl over 4 years ago in reply to Simon yu

TI__Mastermind 21320 points

Hello Simon,

I provide feedback in private message. As you will note, the reference design was not copied exactly, and that affects the design.

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

Regards,

Michael P.

Applications Engineer

Texas Instruments

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TPS23753A: TPS23753A