TPS5430 – The recommended value of FB resistor

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Guru 21045 points

Other Parts Discussed in Thread: TPS5430

I would like to ask a question.

A customer is going to use R1=10.2kohm and R2=1.5kohm in the following condition.

Is this value the optimal?

Also,what is the reason the recommended values of R1 are 10kohm?

(detasheet P15 [For any TPS5430 design, start with an R1 value of 10 kohm.])

Vin= 12.5V

Vout= -9.5V

Iout= 0.8A

*Inverting buck-boost regulator

over 12 years ago

0 Richard Elmquist over 12 years ago

TI__Mastermind 45250 points

Hideto,

The values for R1 and R2 are calculated properly. Be sure to use 1% or better resistors for optimal accuracy.

The value of R1 is specified at 10k to ensure that enough current is available at the feedback node.

Please let me know if you have further questions.

Richard Elmquist

0 Anthony F over 12 years ago in reply to Richard Elmquist

TI__Mastermind 35185 points

Hi Hideto,

The 10kΩ value is also recommended because this is what the internal compensation network was designed to work with. Varying the value of R1 can have a larger impact on the loop response. Different values of R1 may work but if changed by a large amount I recommend checking the loop response.

Best Regards,
Anthony

0 Hide over 12 years ago in reply to Anthony F

Guru 21045 points

Thank you for answer.

Ｉ understood. thank you very much.

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TPS5430 – The recommended value of FB resistor