TPS65217B Wakeup problem

Ferhatx

Hi,

On a custom board with AM335X processor we have faced Wakeup Problem from TPS65217B.

Our design is based on Battery mode. Power supply ramping is <10ms. When power on, there is no any problem for sequencing power rails,

PWR_EN is logic high from CPU and Wakeup is logic high from PMU. But sometimes for examples, sending MLO or

sending Uboot for UART boot mode from Teraterm or in opening Uboot, suddenly Wakeup signal from PMU to CPU

goes logic low and CPU in stuck. Why does Wakeup signal of TPS65217B go low and How can I solve this problem?

Best Regards,

FERHAT

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Ferhat,

Do you have a pullup resistor from Wakeup to VRTC?

Best Regards

Biser

0 Ferhatx over 12 years ago in reply to Biser Gatchev-XID

Intellectual 420 points

Hi Biser,

TPS65217B Wakeup signal have a pull-up to VRTC.

Best Regards,

FERHAT

0 Ferhatx over 12 years ago in reply to Ferhatx

Intellectual 420 points

Additional information :

When Wakeup signal goes logic low, Pgood signal (from PMU, normally 3.3V) goes low with 1sn duration and

after this situation goes high 1.8V not 3.3V. I suppose PMU changes its state from ACTIVE to WAIT 1sn and OFF

state. What are your suggestions?

Best Regards,

FERHAT

0 Ferhatx over 12 years ago in reply to Ferhatx

Intellectual 420 points

Hi Biser,

Do you have any advice?

Best Regards,

FERHAT

0 Biser Gatchev-XID over 12 years ago in reply to Ferhatx

TI__Guru**** 393215 points

Hi Ferhat,

I will try to pull in some help on this issue.

Best Regards

Biser

0 Stephen Nortman over 12 years ago in reply to Biser Gatchev-XID

TI__Expert 4525 points

From earlier post: “When Wakeup signal goes logic low, Pgood signal (from PMU, normally 3.3V) goes low with 1sn duration and after this situation goes high 1.8V not 3.3V. I suppose PMU changes its state from ACTIVE to WAIT 1sn and OFF state. What are your suggestions?”

What is connected to the VIO pin of the PMIC? Typically this will be LDO1 which will give PGOOD a high level of 1.8V. PGOOD should not have more than one high level.

What does the PGOOD pin go to on the processor? Should be PWRONRSTN.

There is probably something that is connected incorrectly. PGOOD can't be sometimes 3.3V and sometimes 1.8V.

Regarding the nWAKEUP signal from the PMIC:

Typically this only responds to:

Rising edge on USB

Rising edge on AC

Falling edge on PB_IN

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TPS65217B Wakeup problem