IMXRT1176 SNVS Mode High Sleep Current

[Vignesh_S]

We are using the below software method for SNVS power mode.

SNVS->LPCR |= SNVS_LPCR_TOP_MASK;

But we are getting around 250-300 uA in our custom board. 

Is there any sequence we need to follow before executing the above method for SNVS to reduce the current? Do we need to handle any pins?

[Vignesh_S · Accepted solution]

Thanks for the help. In our custom board We dont have provision for measuring current in SNVS_IN line alone. But we removed all the components except controller to measure the current. We were still observed more than 200uA current consumption.

But after integrating SNVS_XX pin leakage method mentioned in the AN13104 document, Current is reduced to around 50uA.

[Vignesh_S]

- Are you currently using our power_mode_switch example code for the RT1170 SDK?

Yes. Only SNVS case is implemented in our software.

- Do you have any more pins/modules enabled that could consume power?

It is custom design, but before going to sleep we are shutting down all the power lines of peripherals and GPIO output pins are reinitialized with logic 0 as initial state. We checked the power lines of all the peripherals.

Do we need to handle any SDRAM,TFT,USDHC and FLEXSPI pins before going to sleep?

- How are you measuring the current in your board?

At the power supply terminal positive end, we are checking the current.

- You are currently trying to enter SNVS mode by software. Have you tried entering by hardware (Pressing the ON/OFF button for more than five seconds)?

ON/OFF button method is not tried. But cluster is going to sleep and waking up with the wakeup button as trigger. Is there any issue in using the software method?

[EdwinHz]

Hi @Vignesh_S,

The current consumption measurement for SNVS should be done on the VDD_SNVS_IN pin rather than the power supply, could you please try this instead?

There should be no real need to handle the pins you mention if the SNVS mode is entering correctly. This is also why I also about hardware method of entering this mode. I just wanted to ensure that the SNVS mode is being reached. Please ensure SNVS mode is reached and measure VDD_SNVS_IN pin once it does.

BR,

Edwin.

[Vignesh_S]

Hi @EdwinHz ,

Thanks for the Response.

How can I ensure it reaches SNVS Mode?

[EdwinHz]

Hi @Vignesh_S,

You can ensure SNVS mode by lookin into the PMIC_ON_REQ pad. Before entering SNVS mode, or upon exit, this pin should be HIGH. During SNVS mode, it will be LOW. For more information about this, look into Section "25.3.1 Reset and Power Scheme" and "25.3.2 Finite State Machine (FSM)" of the RM.

[Vignesh_S]

Ok. Then it enters SNVS mode properly. We already measured the PMIC and power lines.

After controller enters to SNVS sleep mode, PMIC pin is low and DCDC & other LDO lines also LOW.

[EdwinHz]

I understand that you are getting 250-300 uA from the power supply, but when measuring VDD_SNVS_IN the current consumption should be typically around these values (depending on the temperature). 

Could you please check this? If the consumption is similar to these specifications, it's likely that the issue lies elsewhere on the custom board.

[EdwinHz]

Hi @Vignesh_S,

Could you please clarify:
- Are you currently using our power_mode_switch example code for the RT1170 SDK?
- Do you have any more pins/modules enabled that could consume power?
- How are you measuring the current in your board?
- You are currently trying to enter SNVS mode by software. Have you tried entering by hardware (Pressing the ON/OFF button for more than five seconds)?

BR,

Edwin.