TPS23881EVM-008: Output power can't reach 802.3bt class8

Hideki Hayashi1

Part Number: TPS23881EVM-008
Other Parts Discussed in Thread: BOOST-PSEMTHR-007, , TPS2373-4EVM-758, TPS23881, USB2ANY

Hi Teams,

Customer is evaluating PoE with TPS2373-4EVM-758, TPS23881EVM-008, BOOST-PSEMTHR-007.

They use autonomous mode by shorting a bottom of J5 in EVM (=4 pair 90W). After that, they connect J19 and J21 of the PSEMTHR and PD side of 4-pair, and tried to increase a load current. Both reach 5.3A (30W) as the highest, so were not able to reach the bt opreration.

They also done evaluation at only PD device. It reached 14A so it works well.

Do you think there are any issue on PSE device?

over 3 years ago

0 Penny Xu over 3 years ago

TI__Genius 15655 points

Hi Hideki,

Which port did you connect the PD to? Did you connect the PD to 4 pair ports on the right side? If you connect the PDs to the 2 pair ports on the left, the configurations don't apply to these ports as they are 2 pair wired ports.

A question for you, do you have an MCU in the system to load SRAM code to TPS23881 device? And do you have control of both sides of the cables(PSE and PD)? Thanks.

Best regards,

Penny

0 Hideki Hayashi1 over 3 years ago in reply to Penny Xu

TI__Expert 5990 points

Hi Penny,

I think the connection is right. Please see below picture. The Red line means jumper to set the PoE class for autonomous operation. In both J9 and J21, there are no power communication over 30W.

There are no MCU in the system to load SRAM code, and I don't understand "do you have control of both sides of the cable?". What does it exactly means?

0 Hideki Hayashi1 over 3 years ago in reply to Hideki Hayashi1

TI__Expert 5990 points

Hi Penny,

Sorry that I couldn't paste the file. I try it again.

0 Penny Xu over 3 years ago in reply to Hideki Hayashi1

TI__Genius 15655 points

Hideki,

You connection looks correct. It is very weird. Can you connect USB2ANY to the board and open TPS2388x EVM GUI to check the port status when you increase the power to >30W? Thanks.

Best regards,

Penny

0 Hideki Hayashi1 over 3 years ago in reply to Penny Xu

TI__Expert 5990 points

Hi Penny,

Customer doesn't have USB2ANY to check the port status. I had advised him to check the handshaking finger, then customer said the fifth finger is triggered up, but there's only 30W communication.

In their evaluation status, the issue doesn't happen when using other company's PSE. 90W communication is achieved when (Other PSE + TI PD ), (Other PSE + Other PD), but 30W is achieved when (TI PSE + TI PD), (TI PSE + Other PD).

What do you think the possibilities are?

0 Penny Xu over 3 years ago in reply to Hideki Hayashi1

TI__Genius 15655 points

Hi Hideki,

Is there any I2C host available to read the PSE registers status (0x06,0x08,0x0A)? Thanks.

Best regards,

Penny

0 Hideki Hayashi1 over 3 years ago in reply to Penny Xu

TI__Expert 5990 points

Hi Penny,

Customer is evaluating the EVMs standalone, so there is no I2C host available.

Could you have other solutions without I2C control?

Regards,

Hideki

0 Penny Xu over 3 years ago in reply to Hideki Hayashi1

TI__Genius 15655 points

Hi Hideki,

Please order USB2ANY and download TPS2388x EVM GUI to read PSE registers to debug the issue. Thanks.

Best regards,

Penny

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TPS23881EVM-008: Output power can't reach 802.3bt class8