TPS2561: Possible for current to flow back from output side to the input side

Conor

Mastermind 9310 points

Part Number: TPS2561

Tool/software:

Hi,

When the TPS2561 EN pin is disabled, is it possible for current to flow back from +5V2 to the input terminal (+5V1)?

If the answer is yes, I will consider adding a diode to the input side to prevent backflow.

Thanks,

Conor

4 months ago

0 Eric Hartigan 4 months ago

TI__Expert 5035 points

Hi Conor,

With EN disabled, my expectation is you should see IREV = 10 nA into the OUT pin. I will double check this in our lab, but it will take a few days since I don't have samples on hand.

Regards,
Eric

0 Conor 3 months ago in reply to Eric Hartigan

Mastermind 9310 points

Hi Eric,

Thanks. Do you have any update?

Conor

0 Eric Hartigan 3 months ago in reply to Conor

TI__Expert 5035 points

Hi Conor,

I received samples this afternoon. I will have this behavior checked on Monday.

Regards,
Eric

0 Conor 3 months ago in reply to Eric Hartigan

Mastermind 9310 points

Hi Eric,

Okay, looking forward to your updates.

Thanks,

0 Eric Hartigan 3 months ago in reply to Conor

TI__Expert 5035 points

Hi Conor,

I was able to check this behavior in the lab today.

If IN = 5.1 V and EN = HIGH, the 5.2 V supply will force current back to the input.

If IN = 5.1 V and EN = LOW, the current into OUT will be up to 1 uA.

If IN = 0 V and EN = do not care, the current into OUT will be up to 1 uA.

Regards,
Eric

0 Conor 3 months ago in reply to Eric Hartigan

Mastermind 9310 points

Hi Eric,

Thank you for your verification. Sorry, I was unclear about how I described it.

The output voltage (+5V2) and input voltage (+5V1) are both +5.0V. They are not 5.1V and 5.2V respectively.

We would like to know whether there is a risk of reverse current flow when the input/output voltage is +5.0V and the enable function is OFF.

Also, if reverse current does flow, is inserting a protection diode a reasonable countermeasure?

Thanks,

Conor

0 Eric Hartigan 3 months ago in reply to Conor

TI__Expert 5035 points

Hi Conor,

It's the same behavior as described above if both supplies are 5.0 V. As long as EN is OFF, there will only be up to 1 uA current into OUT.

Regards,
Eric

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TPS2561: Possible for current to flow back from output side to the input side