TPS62177 Max allowed Vout when Vin is floating

Anders Knutson

Other Parts Discussed in Thread: TPS62177

Hi,

I plan to use the TPS62177 (Vout = fixed 3.3V) in a configuration where Vin is 9-26V.

I would also like to be able to supply this board with 3.3V directly when the 9-26V input is floating (not connected).
That means that Vout (SW, VOS, SLEEP pin) will be 3.3V in my configuration when Vin is floating.

Am I allowed to do so?
If not, are there any suggestion for how to change the circuit to make it possible to supply the board with 3.3V when the 9-26 input is not connected?

over 10 years ago

0 Chris Glaser over 10 years ago

TI__Guru*** 148810 points

There should be several other threads on this basic question. The answer is generally the same for most devices.

Yes, you can do this. Note that you will have a voltage on Vin through the high side MOSFET body diode, so other circuits on the input voltage will be powered.

0 Anders Knutson over 10 years ago in reply to Chris Glaser

Prodigy 30 points

Thank you very much for your answer.

Power management

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TPS62177 Max allowed Vout when Vin is floating