TPS62175: TPS62175 when opening and shorting the FB terminal resistance, there is a question about VOS operation.

Bob Lee62837

Mastermind 7230 points

Part Number: TPS62175

Dear support member,

My customer used TPS62175.

I have a question.

When opening and shorting the FB terminal resistance with TPS62175, there is a question about VOS operation.

Q1
When the FB terminal resistance is opened and shorted, what is the IC output voltage when the FB function can not be controlled?

Q2
In the data sheet, it is described as 7.4 V(typ) when the FB pin is open, but is the output voltage controlled at 7.4 V?

Q3
In the explanation, only Typ is listed, but how much is the range?

Best regard.
Bob Lee.

over 5 years ago

0 Chris Glaser over 5 years ago

TI__Guru*** 142750 points

Hi Bob,

1. The FB pin is the input to regulate the output voltage. If it is open, the output voltage is not known. If FB is shorted, the output voltage should go to Vin for any buck. With TPS62175, it is limited to 7.4V.

2. The output voltage will not go higher than 7.4V (typical).

3. This is not specified.

0 Bob Lee62837 over 5 years ago in reply to Chris Glaser

Mastermind 7230 points

Dear Chris Glaser,

Thank you veru much for reply.

I reply my customer your answer.

Best regard.
Bob Lee.

0 Bob Lee62837 over 5 years ago in reply to Bob Lee62837

Mastermind 7230 points

Dear Chris Glaser,

May I ask a add question?

Although when the FB pin is open the output voltage is 7.4 V, the absolute maximum rating of VOS pin is 7 V.

Is there any problem with VOS pin?

Best regard.
Bob Lee.

0 Chris Glaser over 5 years ago in reply to Bob Lee62837

TI__Guru*** 142750 points

Hi Bob,

The 7.4V clamp is just to safeguard the load/system when there is an abnormal fault. This is not the intended operation.

Since 7.4V is slightly above the 7V abs max rating, there may be some lifetime reduction of the device. I assume that the end customer would discover that there is an issue with the system long before the lifetime would be reached.

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TPS62175: TPS62175 when opening and shorting the FB terminal resistance, there is a question about VOS operation.