TPS23880: TPS23880 output power issue

Darren Yang

Expert 2000 points

Part Number: TPS23880
Other Parts Discussed in Thread: TPS23881, TPS23881EVM-008

Hi Sir

our customer now use TPS23880+ TPS2372-4 design as 90W，when use TPS23880 can connect with TPS2372-4，but the output power is 54W，but if use other poe，it will can not connect to TPS23880, but the TPS2372-4 can connect to other's PSE, however, the output power is only 25W, the sch as follow, pls help check it and give more suggestions,tks!

5040.TPS2372sch.pdf 0842.TPS23880sch.pdf

over 4 years ago

0 Penny Xu over 4 years ago

TI__Genius 15655 points

Hi Darren,

Actually I am surprised you got power from TPS23880 without any software control. TPS23880 doesn't have autonomous mode which means it need a host to configure during power up through I2C bus (configure the ports to 4 pair mode, set the power allocation, set port operating mode, enable detection and classification). If you don't have an MCU or CPU, TPS23881 is a perfect part for you as TPS23881 has autonomous mode and you can set the port power allocation through AUTO pin(pin 52). TPS23881 and TPS23880 are pin to pin compatible expect pin 52. Please try to add a resistor(7.7 kohm if wanting to set to 90W) and 10nF cap in parallel between AUTO pin and ground. Thanks.

Best regards,

Penny

0 Darren Yang over 4 years ago in reply to Penny Xu

Expert 2000 points

Hi Penny

thanks for your suggestions, however, if use TPS23881 design as output power 90W, it requested be used all the DRAIN1-DRAIN8? could you help to provide the meet output power 90W SCH for us ,tks!

0 Penny Xu over 4 years ago in reply to Darren Yang

TI__Genius 15655 points

Hi Darren,

Please check TPS23881EVM-008 schematic. Basically, it is the same as TPS23880 schematic except the AUTO pin design. You can only use 2 of the channels to deliver 90W. You can modify your existing board (replace TPS23880 with TPS23881, add a cap and a resistor between AUTO pin and GND).Thanks.

Best regards,

Penny

0 Darren Yang over 4 years ago in reply to Penny Xu

Expert 2000 points

Hi penny

if customer want to design POE power, What are the conditions for developing a PoE product under consultation? For example, joining associations, certifications, etc.?

0 Penny Xu over 4 years ago in reply to Darren Yang

TI__Genius 15655 points

Hi Darren,

Please check the FAQ here:http://e2e.ti.com/support/power-management/f/196/p/724427/2672978?tisearch=e2e-sitesearch&keymatch=POE%252525252520EA#2672978.

You can get your PoE products EA certified to ensure interoperability. Thanks.

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TPS23880: TPS23880 output power issue