AM62A7-Q1: Development of fast power on/off function

Hello Ziming Yi, 

Thank you for the query.

I am not able to understand the query.

Could you please elaborate the query in English for me to review and support.

Help me uncderstand the power solution you are using. 

Regards,

Sreenivasa

Hello Sreenivasa,

Sorry, there were some errors while editing the content.

We would like to ask
1. Is SOC in an abnormal state within a certain voltage range?

2. How to quickly start SOC when it is in an abnormal state?

3. Will the circuit design of adding supercapacitors to the motherboard affect the working state of SOC?

Regards,

Garett

Hello Ziming Yi, 

Thank you for the inputs.

Could you please share the power architecture you are using.

Regards,

Sreenivasa

Hello Sreenivasa,

The PMIC chip we are currently using is TPS65931211RWERQ1

Pin usage as shown in the diagram

May I ask which pin or register can be controlled to actively reset this PMIC?

Regards,

Garett

Hello Garett,

Thank you for confirming the PMIC part number.

I am assigning to the expert to support.

Regards,

Sreenivasa

I have tried configuring the SOFT_REBOOT_REGIST of PMIC and writing 0x01 into this register to achieve the software reset operation of PMIC.

But it seems to have no effect. During the discharge process of the supercapacitor, resetting the PMIC, reconnecting VCC for power supply, and SOC also failed to start normally

So I want to know if there are any other registers that can make PMIC shut down/stop working normally

Hello

I would like to synchronize the latest debugging progress and problem points

Firstly, in our circuit design, VCCA is supplied in two ways. When connected to VCC, VCCA is provided by VCC and measures around 4.87V. When VCC is disconnected, VCCA is provided by EDLC.

According to the state machine transition diagram, it can be concluded that:

We have 4 situations to consider

 1.Under normal circumstances, the process from NO SUPPLY to connecting VCC for power on is as follows:

NO SUPPLY——>INIT——>BOOT BIST——>Mission States

 2.If VCC is disconnected and EDLC is used as the power supply for VCCA, and this process is never reconnected to VCC

 3.Disconnect VCC, EDLC serves as the power supply for VCCA, and the VCCA voltage is below about 3.2V. At this point, it can be considered as entering an abnormal working state. What needs to be confirmed here/What I want to ask is

(1) Is PMIC currently in the BACKUP state?

(2) From the state diagram, it appears that only VCCA<VCCA_UVLO (2.75V) will enter the BACKUP state. Why is it that SOC printing cannot be seen when VCCA<3.2V is actually measured. Is it possible that PMIC is still in a mission state at this time, but the power supply is insufficient to support the normal operation of SOC?

 4.Connect VCC in an undervoltage state, and VCC serves as the power supply for VCCA. At this point, VCCA is definitely greater than VCCA_UV.

Why didn't you go through the process of NO SUPERY ->INIT ->BOOT BIST ->Mission States in this situation? It is possible to go NO SUPERY ->INIT ->LP STANDBY. Or it's unclear what state PMIC is in at this moment. Because in this situation, it is not possible to read the registers of PMIC. So what needs to be confirmed is/what I want to ask is

(1) What is the status of PMIC in this situation? Is it in LP STANDBY or any other state?

(2) What means should I use to confirm the current status of PMIC?

Explanation: Any_State=All States Except NO SUPERY

If the content of the data manual is correct (please help confirm if the following parameters are correct):

The two ways to switch from All States Except NO SUPERY to the BACKUP state are:

1 VCCA<VCCA_UVLO（2.75V）

2 LDOVINT UVLO Condition=LDOVINT < 1.64V

For method 1, if the measured VCCA is less than 3.2V, the printing of SOC cannot be seen; When VCCA<1.6V and VCC is reconnected, the startup print of SOC can be seen.

For method 2, VOUT_LDOVINT measures 1.75V when connected to VCC power supply. After disconnecting VCC from EDLC power supply, the voltage remains at 1.75V. After printing stops for 3-4 seconds, 1.75V will drop directly to 0V. It will take about 8 seconds to see the start printing of SOC when connected to VCC.

If the content of the data manual is correct (please help confirm if the following parameters are correct):

There are two ways to switch from the BACKUP state to the NO SUPERY state:

1 LDOVRTC UVLO Condition=LDOVRTC<1.64V

2.The condition for Shelf Mode enabled is

(1) In the mission state, let LDORTC_DIS=1

(2) Immediately reduce the VCCA voltage to 0V (remove the main power supply)

For method 1, it appears that reconnecting VCC when LDOVRTC<1.64V does indeed result in SOC startup printing.

For method 2, I can use SOC to write the PMIC register pin LDORTC_DIS=1 through I2C,

What I want to ask is: how can I set the voltage of VCCA to 0V? When I disconnect VCC, VCCA will be provided by EDLC, so there is no way to immediately drop to 0V.

Regards,

Garett