TPS2556-Q1: Voltage leakage

Roy Chou1

Part Number: TPS2556-Q1
Other Parts Discussed in Thread: TPS2556

Hi Team,

Please see the attachment. We may have another VBUS voltage on output side. If the VBUS voltage on output side is occur and then EN will be high to let TPS2556 turn off. (please ignore body diode path first)

But If we power off the VBATT, we find that there is voltage leakage from TPS2556 output side to input side.

Could you let us know how to avoid the issue?

[Garmin] TPS2556.pdf

Roy

over 3 years ago

0 Ansel Song over 3 years ago

TI__Expert 3890 points

Hi Roy,

I think you can add a diode on TPS2556 OUTPUT to avoid reverse voltage.

Regards,

Ansel

0 Roy Chou1 over 3 years ago in reply to Ansel Song

TI__Genius 13045 points

Hi Ansel,

Yes, we know how to solve it. But we would like to know why TPS2556 is turn on internally in our condition.

Roy

0 Ansel Song over 3 years ago in reply to Roy Chou1

TI__Expert 3890 points

Hi Roy,

Because the parasitic diode of the internal MOS .

Ansel

0 Roy Chou1 over 3 years ago in reply to Ansel Song

TI__Genius 13045 points

Hi Ansel,

Do you mean the body diode? I dont think so because as measurement, the Vin is almost equal to Vout which means that there is no voltage drop by diode.

Roy

0 Ansel Song over 3 years ago in reply to Roy Chou1

TI__Expert 3890 points

Hi Roy,

Yes, it is body diode. Could you check this IC whether is broken?

Ansel

0 Roy Chou1 over 3 years ago in reply to Ansel Song

TI__Genius 13045 points

Ansel,

We checked the IC, IC wasn't broken. We doubt that the ~EN, Vin and Vout relationship cause the internal MOSFET turn on.

Did you see the attached file?

Roy

0 Ansel Song over 3 years ago in reply to Roy Chou1

TI__Expert 3890 points

Hi Roy,

Could you remove all IC only TPS2556 for testing? And If there is still issue, you can send e-mail to Michael-tan, can copy me.

Ansel

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TPS2556-Q1: Voltage leakage