TPS6594-Q1: Not powering on

Please follow these debugging steps to help narrow down the problem:

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1112617/faq-tps6594-q1-lp8764-q1-debugging-pmic-behavior-with-interrupt-interpretation?tisearch=e2e-sitesearch&keymatch=faq%3Atrue%20tps6594

Also, the image of the schematic is not readable. Can you post a .pdf copy?

Hi,

Since I'm using pre-programmed PMIC TPS65941515, the register bits LDOx_EN=disabled and LDOx_RV_SEL=Enabled. But in my board even when PMIC outputs are not generated there are some backdrive voltage at PMIC output rails. Is this the reason for PMIC not turning ON

Regards,
Kaushal

So can I change the register set LDOx_RV_SEL to disable and LDOx_EN to enable directly by changing register file of this PMIC, do you think this mite solve the issue

Michael Gambrill said:

LDOx_RV_SEL =1

Checked by doing this. First time it worked. Then facing the same issue. Voltage not generating.

Michael Gambrill said:

Your best option is to stop leakage or add a small pull down resistor to get the voltage below 150mV. 

Done this too. But residual voltage not dropping down. Is there any permanent way to set LDOx_RV_SEL=0 ?

Also observed that when I set LDOx_EN to 1 all outputs gets generated. By doing that manually will there be any issue? Or can we make this LDOx_EN to 1 in register value of TPS65941515 PMIC. Or can you say how does this LDOx_EN automatically sets to 1 so that I can get the root cause of this issue

Also these are the interrupts I'm getting when power is not generating from PMIC

Please check and help me resolve this issue

Regards,
Kaushal

Kaushal C said:

Also these are the interrupts I'm getting when power is not generating from PMIC

The interrupt read out indicate an issue with LDO2. If it experiences a fault, the PMIC will immediately execute a recovery attempt. 

Kaushal C said:

Also observed that when I set LDOx_EN to 1 all outputs gets generated. By doing that manually will there be any issue? Or can we make this LDOx_EN to 1 in register value of TPS65941515 PMIC. Or can you say how does this LDOx_EN automatically sets to 1 so that I can get the root cause of this issue

When the PMIC's enable pin is pulled up, it tries to execute the TO_ACTIVE sequence. Please see the linked user guide about NVM settings and state machine of the '1515:

https://www.ti.com/lit/pdf/slvucd4

Michael Gambrill said:

The interrupt read out indicate an issue with LDO2. If it experiences a fault, the PMIC will immediately execute a recovery attempt. 

Yes, I've solved this issue by changing the threshold to 6%. Then without mounting DRA821U processor power was up in my board. Once we mounted processor, still same issue. LDO rails we are getting backdrive voltage of 0.9V inplace of 1.8V. Can you please tell me the reason for this issue

Also now found out the root cause for PMIC not turning on, I'm using PMIC and separate LDO for 1.8V rails in DRA821U processor. Since my separate LDO will turn on fast and is fed to processors VDDSHV pins. There is backdrive from processor and due to residual voltage PMIC is not up. 
So from PMIC enable to LDO1 out which is first sequence, there is 6.3ms delay. Can you please tell me how to reduce this delay in TPS65941515 PMIC

Attached picture of sequence

Attached Schematics of PMIC LDO section for reference

Regards,
Kaushal

Any Updates?

Regards,
Kaushal