PoE++ PD controller

veera venkateswara rao pusala

Other Parts Discussed in Thread: TPS23754

Hi,

I have PoE++ Mid-span PSE controller , which contains LTC4274A-4 PSE controller. for that i am going to design the PD controller which support 90W power. please suggest me which TI chip is suitable for my application

Regards,

Veera

1104.LTC4274_poe++.pdf

over 14 years ago

0 Eric Wright over 14 years ago

TI__Mastermind 42795 points

Ti doesn't have a PD controller suitable for this power level.

0 veera venkateswara rao pusala over 14 years ago in reply to Eric Wright

Intellectual 280 points

Hi,

thanks for reply.

above specified power level 95W is belongs to 4- pairs, it can support 45W power over 2-pairs. my question is how much maximum power TI PD can support during LEGACY mode?

Regards,

Venkat

0 Eric Wright over 14 years ago in reply to veera venkateswara rao pusala

TI__Mastermind 42795 points

Take a look at TPS23754. It is a type 2 PD and dc/dc controller designed for 25W, 2 pair applications. The minimum current limit for the PASS FET is 850mA. For 45W, you would need 53V in at 850mA.

TI has a couple of high power reference designs using TPS23754. The first design is 40W output (24V, 1.7A) and this is achieved by "boosting" the current limit of the PASS FET using external BJT power transistors. The second design utilizes parallel, current shared TPS23754 controllers on all four pairs.

Design 1: http://focus.ti.com/docs/toolsw/folders/print/pmp5177.html

Design 2: http://focus.ti.com/docs/toolsw/folders/print/pmp5236.html

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PoE++ PD controller