Current consumption in system off sleep

[powerup]

Hi.

I am using nrf52832, SDK15.0.0, and S132 SD.

I am using a custom board.

I checked the consumption current of 80uA in system off sleep state.

I want to lower it to 10uA but I do not know what to do.

The measurement methods and codes are as follows.

<measurement method>

<code>

int main(void){

  sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);
  
  nrf_gpio_cfg_output(HX711_SCK_PIN);
  nrf_gpio_pin_write(HX711_SCK_PIN,true);	//HX711 power down
  nrf_delay_us(100);	// 60us by datasheet
  
  NRF_POWER->SYSTEMOFF = 1;

}

What can I do to lower the current consumption?

Thank you.

[powerup]

I removed all the parts from the custom board and left only the MCU and peripheral devices.
But it also consumes 80-90uA of current.
Is there anything you need to configure in the boot loader?

[Stian Røed Hafskjold]

Hi, when you put the nRF52832 to system OFF mode it consumes about 0.3 uA. If you measure 80 uA there must be something else on your custom board that consumes current.

Always include a main loop at the bottom of your main() function. Event though you put the chip to system OFF.

[powerup]

Hi.

I modified main as follows.

int main(void){

  //nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);
  //NRF_POWER->SYSTEMOFF = 1;
  sleep_mode_enter();
  
  while(1){ 
    nrf_pwr_mgmt_run();
  }
}

But it also consumes 80-90uA.

My board only has nRF52832, LC and regulator.

[Stian Røed Hafskjold]

The nRF52832 does not consume 80uA in system off mode, so there must be something else on your board that consumes current.

I see that the regulator you are using has a quiescent current of 90uA when the output current is 0mA: http://www.ti.com/lit/ds/slvs144d/slvs144d.pdf

[powerup]

TPS76033 is replaced with mic5203-3.3.

Quiescent current in the datasheet is Typ: 0.01uA.
But my board still consumes 90uA.

I will remove the regulator and battery and test it with a power supply.

Do you think the firmware is OK?