TPS40057: please help to check the SCH

Gary Wang1

Intellectual 350 points

Part Number: TPS40057
Other Parts Discussed in Thread: LM25145,

Dears,

Customer requirements: input 12 ~ 60V, output 4V20A, please check the schematic.

Thank you. Looking forward to your responses and suggestions.

over 6 years ago

0 Samuel Jaffe over 6 years ago

TI__Mastermind 25590 points

Gary,

Sorry for the delay. I will take a look and respond in a few hours. Thanks for your patience.

-Sam

0 Samuel Jaffe over 6 years ago in reply to Samuel Jaffe

TI__Mastermind 25590 points

Gary,

You say the customer needs an input up to 60V. This part operates up to 40V. You will need a new part for this application.

-Sam

0 Samuel Jaffe over 6 years ago in reply to Samuel Jaffe

TI__Mastermind 25590 points

Gary,

Here is a list of parts which fit your spec.

-Sam

0 Gary Wang1 over 6 years ago in reply to Samuel Jaffe

Intellectual 350 points

Dear Sam,

Sorry for my mistake, the input is DC12V~36V, not 60V, please help to check the SCH.

thanks.

0 Samuel Jaffe over 6 years ago in reply to Gary Wang1

TI__Mastermind 25590 points

Gary,

If it's early in the design cycle I'd recommend using LM25145. LM25145 has WEBENCH for design assistance and other advantages. But assuming you're sticking with TPS40057, here's my schematic review:

L can be reduced to 3.6uH or above.
Check the ESR of the input and output caps. You may need some ceramics there as well.
Increase the VIN cap to 1uF and place it close to the pins to create a small loop from VIN pin --> cap --> PGND pin
Boost cap should be increased to 0.1uF
Make sure the TPS40057 can drive the chosen FETs.
Increase BP5 cap to 1uF
And more. I'm seeing that every ceramic capacitor has a value of 100pF. Either this is a mistake or you'd like me to do these calculations for you. Please read through the datasheet to find appropriate values or switch to a part with WEBENCH to assist.

-Sam

Power management

Power management forum

TPS40057: please help to check the SCH