How to make tlf35584 enter sleep with tc377?

[oska874]

We use tc377 with tlf35584. We can make pmic(tlf35584) enter sleep mode with mcu sleep, but cannot make pmic enter sleep mode with mcu standby. In mcu standby mode we have made current far below 100ma, but pmic enters sleep and quickly exit. While in mcu sleep mode, we make current below 100ma but higher than standby mode , and pmic can enter sleep until wakeup operation. As our guess, it's beacue mcu enter standby mode reduce current too slow outside pmic's requirement(max 1.6ms). Is this guess correct? How can we make pmic enter sleep with mcu goto standby mode?

[Vishnu_Nambrath]

Hello, 

Thanks for the detailed explanation 🙂 
I am also suspecting how fast the current is decaying when the MCU is in standby mode. 

This can be verified by monitoring tracker1 voltage and LDO_uC current. Keep the tracker1 disabled in the sleep mode and enabled in the normal mode. This tracker is monitored just to check when the sleep mode is getting activated. By this time LDO_uC current should be below the threshold.  

Monitor the below duration. 
MCU transition to standby mode (we should see the current decaying) --> PMIC transition to sleep mode (we should see the tracker turns off)
When the tracker turns off, check whether the LDO_uC current is below the threshold. 

Please let me know your feedback. 

Regards 
Vishnu N

[AhmedSaber]

Hi Vishnu_Nambrath

I have a similar case here.
Can we just send SPI command to turn off the QT1,2 then send the TLF into sleep then send the MCU into sleep?

[Vishnu_Nambrath]

Hello, 
The trackers are switched ON or OFF depending on the configuration by the state transition request to move into SLEEP and cannot be changed in SLEEP-state. 

TLF will not stay in sleep state and move to wake state if the LDO_uC current is more than the threshold value. 

Regards 
Vishnu N

[Vishnu_Nambrath · Accepted solution]

Hello, 

You can also check the wake-up status flag - WKSF for getting the reason for the wake-up event. 

Regards 
Vishnu N