High Power consumed by nRF52832

[alpeshpatel283]

Hello,

We have constructed a custom board of nRF52832 via I2C communication with sensor and INT based wake up. Following configuration enable

• DCDC Power Enable
• Disconnected TWI line in sleep mode
• Counter based RTC

 I measured the current consumption of custom board using real-time current measurement the multimeter and it is showing as 3.75mA with 3.3V of the power supply.

This consumes high current than expected and not able to suspect what is causing this much of current consumption.

Do you have any idea what could be causing this, and how to fix it?

Looking forward to hearing from you.

Thanks.

Regards,

Alpesh Mandani

[John]

That current is just about exactly the run current of the CPU while running from flash with the DCDC enabled. Best guess based on what you've told us is that you are not going to idle/sleep, or if you are something is waking you up very quickly after you enter idle/sleep. One thing I would check is to ensure all of your wakeup source interrupt flags are cleared before attempting to idle/sleep.

[MartinBL]

In addition to clearing flags etc. as John DeWitt mentions, this is common cause for the CPU to be running: Errata 87: Unexpected wake from System ON Idle when using FPU. So if you are using float variables in your code make sure to apply the workaround mentioned in the errata. 

[alpeshpatel283]

Hi John,

Thanks for your support. Will check your suggestions and get back to you on further.

Yes, we are not able to put device in sleep/ idle mode.

We have used 100ms advertising interval . Could a small interval effect to core enter in to sleep or idel mode?

Let me know your thoughts on this.

Regards,

Alpesh

[alpeshpatel283]

Hi Martin,

Sure, I will check and apply as per errata workaround.

Thanks,

Regards

Alpesh

[John]

Hi Alpesh,

While 100ms is a relatively fast advertising interval, it is still a *lot* of time to sleep. The core should still be able to get to idle/sleep mode in that time quite easily. 

Regards,

John