WEBENCH® Tools/TPS54424: Minimize Vout deviation

Alpha H

Part Number: TPS54424
Other Parts Discussed in Thread: TINA-TI

Tool/software: WEBENCH® Design Tools

Hi team,

I've been using the TPS54424 and the WEBENCH tool to create a power design with Vout = 3.3V @ 3A. I've been running load transient simulations on the design and I'm experiencing Vout deviations around 4-5%. I'm trying to minimize the Vout max deviation to 3%.

I've been increasing the filter response, (Cout) to compensate for the voltage spikes, but it doesn't seem to be changing anything in WEBENCH. I've also been looking at the datasheet calculations. Is this the correct way to minimize voltage over/undershoots, or should I be trying something different?

Graph below:

Thanks,

Arthur Huang

over 6 years ago

0 Alpha H over 6 years ago

TI__Genius 10855 points

0 JohnTucker over 6 years ago in reply to Alpha H

TI__Guru**** 191445 points

Generally you can improve the transient response by:
Increasing Cout
Increasing loop BW
Decreasing Lout.

The initial voltage drop is mostly caused by the load step current being drawn directly from the output capacitors though. I would recommend you try the pspice or TINA-TI transient models, to model your load step response. I think they are more flexible than working in Webench.

0 Alpha H over 6 years ago in reply to JohnTucker

TI__Genius 10855 points

Hi John,

Thanks for the reply. I think my issue might be with Webench, I drastically changed my Cout, Bandwidth, and Lout, and the change I got was from Vout = 3.421215 to Vout = 3.421176.

I will make the same changes in TINA and try to proceed from there. Thanks for the help!

Regards,

Arthur

Power management

Power management forum

WEBENCH® Tools/TPS54424: Minimize Vout deviation