nPM1100 Operation

[fmighani]

We are using nPM1100 along with a STM CPU. When we put the CPU into deep sleep, it takes one minute for the current to go down to 20uA from 500uA.

We were expecting the nPM1100 goes down to low load mode right away not after 1 minute.

The question is, does nPM1100 need the 1 minute to detect low-load to drop the current?

Please advise.

Thanks.

Kind Regards,

Farhad Mighani 

[runsiv]

Hi Farhad

I'm checking internally and will get back to you

Regards

Runar

[runsiv]

Hi Farhad

Could you clarify a bit regarding your setup. As of now I have the following questions:

1. Is it a battery only system?

2. Are you using 

3. Are you using the DCDC buck to supply your MCU, if so what is the battery voltage, buck output voltage and what is the mode of the buck, automode or forced PWM?

Regards

Runar

[fmighani]

Hi Runar,

Thanks for getting back to me.

We are using nPM1100 to generate 1.8V to feed the MPU. We have both options to feed nPM1100 from a battery or USB interface. When we put the MPU into deep sleep, it is powered via the USB interface (wall powered).

Please see below the configuration to answer some of your questions. I hope this helps to help us! Thanks. Kind Regards, Farhad

[runsiv]

Thanks for the information. 
I have forwarded the information internally and will get back to you as soon as I have something

Regards

Runar

[runsiv]

Update 

If you are supplying from VBUS input, then when in low current the DCDC might go in low power mode. But the rest of the chip is still requesting biasing current and references for the VSYS regulator and the battery charger to operate. So it seems normal to us to keep current consumption around 500uA. It is surprising it goes down to 20uA after 1 minute.So i'm asking internally if they have input.

Edit: 

Do you have any information regarding the voltage variations on VBAT, VBUS, or VSYS? 

Regards

Runar