TPS40170: Output impedance for PDN

VALAYER hugo

Part Number: TPS40170

Regarding TPS40170 « wide-input synchronous PWM buck controller », in a power distribution network planning.

I need to estimate the output impedance of this voltage regulator module. I didn’t find any information about output impedance in the datasheet.

I would like to know if there is any method to perform a frequency analysis of the output impedance for the TPS40170 in our design. Furthermore, I would like to know if there is a method to determine an “output impedance equivalent circuit” for this specific VRM.

Thanks,

Regards,

Hugo

over 6 years ago

0 Orlando Murray over 6 years ago

TI__Mastermind 22301 points

Hugo,
I'm not sure we specify output impedance, but I've forwarded your question to a product expert.
We will get back to you soon,
-Orlando

0 David Baba over 6 years ago

TI__Mastermind 40060 points

Hello Valayer,

Recommend using the online calculator for stability analysis as the information is readily available. See link to calculator which include Bode plots to determine adequate margins for stability.

www.ti.com/.../getliterature.tsp

I hope this helps?

0 VALAYER hugo over 6 years ago in reply to David Baba

Prodigy 20 points

Hello David,

Your calculator is useful for voltage regulator design but not for impedance analysis.

I might have found a solution :

Using Vatché Vorpérian’s "PWM switch model in voltage mode, continuous conduction mode" (VM-CCM) and a comparator block i'm able to model the TPS40170 in my design, using Spice. This modelling allows impedance analysis.

Regards,

Hugo

0 David Baba over 6 years ago in reply to VALAYER hugo

TI__Mastermind 40060 points

Glad you were able to find a solution Valayer.

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TPS40170: Output impedance for PDN