TPS23753A, help with buck configuration, 24Vout

Joseph St. Amour

Other Parts Discussed in Thread: TPS23753A, TPS23754, TPS23754EVM-420, TPS2379, TPS40061

I'm looking at application report SLVA440

http://www.ti.com/lit/an/slva440/slva440.pdf

Is it possible to configure this buck circuit to run at 24V? Ideally I need 25W, so I need to address component changes, but what do I need to change to get 24Vout?

-Joe

over 12 years ago

0 Eric Wright over 12 years ago

TI__Mastermind 42795 points

SLVA440 is really geared towards a type 1 (<13W) POE application and uses TPS23753A (type 1 PD controller). I couldn't find any handy existing reference designs that support 24V at 10W, but you should be able to achieve the 24V output (your input voltage range now will be limited to ~33V minimum) with a few simple changes including (but not limited to): R16 (output voltage setpoint), L2 (use larger inductance), C5/C6/C8, as well as some tuning of the feedback network (C18, C15, R22).

For a 25W design you should consider using TPS23754 in a flyback configuration (I can send you the details of how to modify TPS23754EVM-420 for a 25W, 24V output).

0 Joseph St. Amour over 12 years ago in reply to Eric Wright

Prodigy 180 points

Eric,

Thank you for your reply.

I ended up switching gears and will be using a TPS2379 with a TPS40061 buck converter. This combination will give me the power I need.

-J

0 Eric Wright over 12 years ago in reply to Joseph St. Amour

TI__Mastermind 42795 points

Sounds good. I take it you found the 24V, 6A synch buck reference design (http://www.ti.com/tool/pmp2428)?

0 Joseph St. Amour over 12 years ago in reply to Eric Wright

Prodigy 180 points

I did, and that is the one I am following. I swapped out the big D2PAK fet to a smaller DPAK one [BUK7275-100A}, and removed one of the SO-8 FETs and replaced it with a slightly higher current, but similar Si7465. In a space constrained applcation.

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TPS23753A, help with buck configuration, 24Vout