NRF52832 Adafruit high power consumption

RE: NRF52832 Adafruit high power consumption

CM — Sun, 22 Aug 2021 23:31:45 GMT

Hello Antoine,

Confirming your findings of 114uA when the device is doing nothing.

I was able to lower the current to 96uA by ground the EN pin for the regulator. From the datasheet, this can consume around 55uA quiescent current.

Given there is only a few other components on the board, the current would either be coming from the USB/TTL bridge, the Lipo charger, or something related to the voltage divide battery monitoring on A7.

RE: NRF52832 Adafruit high power consumption

Stian Røed Hafskjold — Mon, 02 Aug 2021 11:41:39 GMT

I don't know much about the Adafruit board, but is there an onboard debugger as well? If so, usually that's what consumes current. Many of these boards are meant as development platforms, not really low power final products. If you are able to cut the traces that power the debugger, then maybe it the power will go down, but then of course it will be difficult to re-flash the chip later.

RE: NRF52832 Adafruit high power consumption

Antoine — Mon, 02 Aug 2021 07:57:57 GMT

Yes I also think that the adafruit card must have a design problem because it should not consume so much.

With your code, I always get 587 uA when the power supply is on 3.3V and I get 114 uA when I power the board with a battery.

What is the point of having an nrf52 that consumes very little if the adafruit card consumes so much?

RE: NRF52832 Adafruit high power consumption

Stian Røed Hafskjold — Fri, 30 Jul 2021 13:37:08 GMT

Hi, can you try to run code that puts the chip to system OFF mode:

int main(void){
  NRF_POWER->SYSTEMOFF = 1;  // After calling system OFF you should get around 0.3 uA
  for(;;){
    __WFE();                 // If you remove the system off call above, you should get
  }                          // around 2 uA in this WFE loop
}

If you see a higher current, then the board has a higher base current which is not caused by the nRF chip.

RE: NRF52832 Adafruit high power consumption

Antoine — Thu, 29 Jul 2021 13:54:57 GMT

The UART is well disabled in sdk_config.h.

I power the card directly on its 3.3V pin.

But I'm far from theoretical power consumption.

RE: NRF52832 Adafruit high power consumption

Patrick — Thu, 29 Jul 2021 13:39:49 GMT

First thing I would check is to make sure that UART/logging is disabled in sdk_conf.h. That would help get the power down significantly. You will never get the datasheet numbers with the feather though. The onboard serial converter uses quite a bit of power on its own.