TPS65910: TPS65910A31A1 Power up issue

Hello Phil,

Thank you for your reply.

PWRHOLD is connectted to PMIC_POWER_EN pin of the AM3358.

Is this connection correct?

I have one more question.

When I measure the VAUX2, I see it is 4.2V. But it should be 3.3V.

How can I approach the solution?

Thanks,

Best Regards,

Mert

Hi Mert,

  Can you check followings?

1. If the PMIC_POWER_EN pin goes high after power up?
2. What's the VCC4 level? it's VAUX2 input.
3. How many boards you have with the power up issue?
4. Where did you get the PMIC device TPS65910A31A1?

Thanks!

Phil

Hello Phil,

1. PMIC_POWER_EN is always High. There is no button, always high.
2. VCC4 level is 5V.
3. We have 8 boards with the power up issue.
4. I have asked my purchasing departmant. I am waiting for answer.

Best Regards,

Mert

Hi Mert,

Please also check "SLEEP" pin level. Do you see all 8 boards have VAUX2=4.2V? 

Please send an image of the top mark from the PMIC device. 

Please make sure the processors also have been programmed properly. 

Thanks!

Phil

Hello,

I check the SLEEP pin level. It is 0V.

INT1 is 3.3V

I see VAUX2 = 4.2V all boards.

How can I program the AM335x before PMIC power?

How can I load the image without power the PMIC?

Thanks,

Best Regards

Mert

Hi Mert,

  Can you disconnect VAUX2 output from its load to make sure it's real the PMIC output other than charged by other source? If it's still 4.2V without any load connection, then we need to check with our product test team. 

Thanks!

Phil

Hello,

I have measured this voltage before load.

Then I measure the voltage of the C22 capacitor, still 4.2V

Thanks,

Mert 

Hi Mert,

  Can you remove R7 (disconnect load) and then measure the voltage of the C22 capacitor?

Thanks!

Phil

Hi Mert,

   Any update? If it's confirmed VAUX2 constantly outputs 4.2V without any load connections and measuring properly, then these devices need to be returned for failure analysis. FYI, we found the material was assembled in 2018; no failure was reported so far. Customer can send us their reject units.

Thanks!

Phil

Hello Phil,

I was out off office. I will try it then give you to results.

Best,

Mert

Hi Phil,

I have removed the R7 and yes, I see the 3.3V of PMIC VAUX2 output.

But otherside of the R7; it is connectted to AM3358 pins.

When I control the other side of the R7, I see the 4.2V.

NOTE:

There is no kernel in the AM3358 yet.

Best,

Mert

Hello Mert,

The assigned expert will get back to you soon. The delay  was due to Memorial Day holiday in US. 

Regards

Ishtiaque Panhwar

Hello Mert,

  It looks like something is wrong after R7. Would you please check with processor team, if a basic program is necessary before a kernel in the AM3358?

Thanks!

Phil