TPS23881EVM-008: TPS23881 EVB POE Auto pin setting issue

Caspar Lai

Part Number: TPS23881EVM-008
Other Parts Discussed in Thread: TPS23881, MSP-EXP430FR5969, USB2ANY, TPS2373, BOOST-PSEMTHR-007

Dear Sir:

I want try TPS23881 EVB all 4-pair PSE power function for design reference.

60W & 90W.

over 4 years ago

0 Caspar Lai over 4 years ago

Intellectual 380 points

(Sorry ~please forget the previous unfinished post)

Dear Sir:

I want test TPS23881 EVB all 4-pair PSE power function for design reference.

60W & 90W _test OK
But 45W & 75W_ test fail(power out watt not enough, if setting 45W jump=>only about 25~27W)

I only adjustment "TPS23881EVB-008" J5 jump setting.

Could you assist double check this EVB setting are correct ? and please inform to me

If I have any wrong setting, please let me know too.

Thanks so much!

0 Penny Xu over 4 years ago in reply to Caspar Lai

TI__Genius 15655 points

Caspar,

Can you connect the board to TPS2388xEVM GUI and see what kind of fault you get when you have these kinds of failures? Thanks.

Best regards,

Penny

0 Caspar Lai over 4 years ago in reply to Penny Xu

Intellectual 380 points

Dear Penny

Sorry, I'm not so sure about "TPS2388xEVM GUI"?

If you mean use "MSP-EXP430FR5969".

I don't have this module.

Could you verify this issue with your R&D engineer first?
Maybe I have any wrong setting.
Thanks!

PS. I will apply for "MSP-EXP430FR5969" module later

Thanks!

Caspar.Lai

0 Penny Xu over 4 years ago in reply to Caspar Lai

TI__Genius 15655 points

Hi Caspar,

I was referring to the GUI here:http://www.ti.com/product/TPS23881/toolssoftware#softTools. I will try if I can reproduce this issue on my board this week and get back to you. Thanks,

Thanks,

Penny

0 Penny Xu over 4 years ago in reply to Caspar Lai

TI__Genius 15655 points

Hi Caspar,

When you have issues with 45W and 75W, what's the class level of the PD?

When you set the PSE to 45W and the PD is set to above class 5,the PSE should demote the power to 30W.

Similarly, when you set the PSE to 75W and the PD is set to above class 7, the PSE should demote the power to 60W.

Thanks,

Penny

0 Caspar Lai over 4 years ago in reply to Penny Xu

Intellectual 380 points

Hi Penny:

Thanks for your information.

Could you provide this document for reference?

Taiwan TI already assist applied for "USB2ANY" kit.

After I get , I will re-try these setting.

Thanks!

Caspar Lai

0 Penny Xu over 4 years ago in reply to Caspar Lai

TI__Genius 15655 points

Hi Caspar,

This is TPS23881 datasheet on ti.com.

http://www.ti.com/lit/ds/symlink/tps23881.pdf

Thanks.

Best regards,

Penny

0 Caspar Lai over 4 years ago in reply to Penny Xu

Intellectual 380 points

Hi Penny:

Got it! Thanks so much.

I will close this issue.

Thanks again.

Caspar Lai

0 Caspar Lai over 4 years ago in reply to Penny Xu

Intellectual 380 points

Dear Penny:

Sorry! ask about this question again.

I already use TI TPS2373 EVB re-try 45W PSE output function.
But TPS23881 EVB 45W output still not meet spec table.
Can you help confirm this status is correct?

some test data setting below
Test device

PSE: TPS23881EVB-008+"BOOST-PSEMTHR-007"
PD: TPS2373-4EVB-758

Test result

PSE set 45W/PD set class 5=>output about above 40W
PSE set 45W/PD set class 6=>output about under 30W
PSE set 45W/PD set class 7=>output about under 30W
PSE set 45W/PD set class 8=>output about under 30W

Thanks,

Caspar

0 Penny Xu over 4 years ago in reply to Caspar Lai

TI__Genius 15655 points

Hi Caspar,

You test results are expected.

Please me explain the reason one by one.

1.PSE set 45W/PD set class 5=>output about above 40W

[Penny]The PD's DCDC has 90% efficiency. Considering cable losses and PSE's 2.5% PCUT accuracy, ~40W is a reasonable number.

2.PSE set 45W/PD set class 6=>output about under 30W

[Penny]This is expected due to power demotion

3.PSE set 45W/PD set class 7=>output about under 30W

4.PSE set 45W/PD set class 8=>output about under 30W

[Penny]These 2 are also expected. The "class 5" in your highlighted box is a typo. These should be class 4. We are working with documentation team to fix this. Sorry for the confusion.

Best regards,

Penny

0 Caspar Lai over 4 years ago in reply to Penny Xu

Intellectual 380 points

Dear Penny:

Thanks for your information.
But about 45W/75W output power demotion status.
This only for TI chip special define or IEEE802.3bt standard define?

Thanks!

Caspar

0 Penny Xu over 4 years ago in reply to Caspar Lai

TI__Genius 15655 points

Hi Caspar,

It is IEEE802.3bt spec. Please see the table below. Thanks.

Best regards,

Penny

0 Caspar Lai over 4 years ago in reply to Penny Xu

Intellectual 380 points

Dear Penny:

Sorry!~I'm not understand about this table.

could you example use PSE class 5 setting?.

And simple description how to look for this table.

Thanks!

Caspar

0 Penny Xu over 4 years ago in reply to Caspar Lai

TI__Genius 15655 points

Hi Caspar,

Basically, PD assumes PSE is able to send 15W for 1 finger (Type 1 or Type 3), 30W for or 2 finger(Type 2) or 3 finger(Type 3), 60W for 4 finger (Type 3) and 90W for 5 finger(Type 4). If PSE is only able to send 45W, there's no way for PSE to tell PD it can only send 45W instead of 60W. So PSE can only demote to 3 finger 30W to prevent PD drawing more than 45W. Please review this white paper(page 22 to 23) for more details. Thanks.

Best regards,

Penny

0 Caspar Lai over 4 years ago in reply to Penny Xu

Intellectual 380 points

Dear Penny:

Thanks for your information.

This issues close again.

Thanks!

Caspar

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TPS23881EVM-008: TPS23881 EVB POE Auto pin setting issue