TPS54202: Regulated Input Question

David Blanken

Part Number: TPS54202

I am starting a design with the TPS54202. If the part operates with an input voltage supply range of 4.5 V to 28 V, what does the datasheet mean when it says, "This input supply must be well regulated"?

My design will have some 120 Hz ripple. Is there a spec on how much input ripple the TPS54202 can tolerate?

Thanks,

Dave Blanken

Keltron Corporation

over 8 years ago

0 Vental Mao over 8 years ago

TI__Expert 5745 points

It means the input voltage must be during the 4.5~28V, more than 4.5 for start-up, less than 28 to avoid damage the MOS,
For the ripple, would mind to upload the waveform of the SW and output ripple? Maybe the low frequency ripple is caused by the eco-mode in the light load.

0 David Blanken over 8 years ago in reply to Vental Mao

Prodigy 30 points

I am in design mode, still trying to select a good DC/DC chip for my purposes. I don't have a working PC board yet, and output ripple isn't the concern.

My application requires using an unregulated power supply. The supply voltage will be 12 V typically, but will have as much as 3 V 120 Hz ripple on it.

Will that input ripple be a problem for the TPS54202?

Thanks

0 Vental Mao over 8 years ago in reply to David Blanken

TI__Expert 5745 points

So your input voltage will be changed during 9V to 15V. If the gain of the loop in low frequency is not big enough, the output ripple will have the 120Hz signal. So for your design, what's the tolerance for your output ripple?