TPS650830: TPS650830 VR4 startup problem

John Liu59

Part Number: TPS650830

Dear all,

My customer encounter problem when power up the TPS650830 when the 3.3V,1.8VA, 5V, 0.85VA is correctly startup. but initially ENVR4 is set as 0, the VDDQ is 1.5V, which is not expected, the register is all default value, could you please help advise what the possible reason?

Thanks.

over 5 years ago

0 Phil Yi40 over 5 years ago

TI__Mastermind 37480 points

Hi, John,

Do you mean when ENVR4=0, but the VDDQ=1.5V? if so, can you try to separate the PMIC VR4 output with its load to make sure there is no other source to supply the 1.5V?

0 John Liu59 over 5 years ago in reply to Phil Yi40

TI__Intellectual 2735 points

HI Phil,

Yes, when ENVR4=0, there is 1.5V output fro VDDQ, the 1.5V is from the VR4 regulator, we test the SW and find some switching, not from the other source.

My understanding is when ENVR4=0, VDDQ should be 0V, am I right?

Do you have any ideas what the possible reason is for the behavior?

Thanks.

0 Phil Yi40 over 5 years ago in reply to John Liu59

TI__Mastermind 37480 points

Hi, John,

You're right; when ENVR4=0, VDDQ should be 0V or measuring a few mV if there is no other source driving it.

If you're sure no other source connected to it, would you please replace a brand new unit to verify if it's a bad one? if yes, please send us for a FA.

Thanks!

Phil

0 John Liu59 over 5 years ago in reply to Phil Yi40

TI__Intellectual 2735 points

Hi Phil,

Thanks for your feedback.

We found some mistake that connect the BST of VR4 yo VR5, so there is some voltage even if the ENVR =0.

Thanks again for your help.

Let us close the thread.

Thanks.

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TPS650830: TPS650830 VR4 startup problem