Power consumption problem

[Saram]

I have a custom board with nrf52840 with cr2477 battery (1Ah capacity). I was download firmware to board and after a week the battery voltage dropped to critical. In the firmware forcibly turned on dcdc and in power_manage added:
sd_power_mode_set(NRF_POWER_MODE_LOWPWR);
But problem is still here. 

What other critical places are there that you need to pay attention to?

[bjorn-spockeli]

Hi Ivanov,

which SDK version and SoftDevice version are you using?

Have you measured the current consumption of your application using the Nordic Power Profiler Kit  or a power analyzer? If so what kind of current consumption are you seeing?

The power mode during CPU sleep is by default set to NRF_POWER_MODE_LOWPWR, so it is not necessary to explicitly set this. The DCDC on the other hand must be enabled explicitly. Can you post the code that enables the DCDC?

Are you calling the idle_state_handle(), which in turn calls nrf_pwr_mgmt_run, so that the nRF52840 enters the low power idle mode, function in the main for() loop? Have you disabled logging?

The nRF52840 will wake up on interrupts, so if there is a peripheral/peripherals that generate interrupts, then the device might be waking up very frequently. Hence make sure that you disable all peripherals that does not need to run when the CPU is sleeping. 

Best regards
Bjørn

[Saram]

This is my code that have differences from example. 
How I can disable logging?

static void power_manage(void)
{
    sd_power_mode_set(NRF_POWER_MODE_LOWPWR);	
		uint32_t err_code = sd_app_evt_wait();
    APP_ERROR_CHECK(err_code);
		__WFE();
		__WFI();;
}

/**
 * @brief Function for application main entry.
 */
int main(void)
{
    uint32_t err_code;
    // Initialize.
    APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, false);
    ble_stack_init();
    advertising_init();
    //LEDS_ON(LEDS_MASK);
    // Start execution.
    advertising_start();
	sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);
    // Enter main loop.
    for (;; )
    {
        power_manage();
    }
}

[bjorn-spockeli]

Again, which SDK version and SoftDevice version are you using?

   sd_power_mode_set(NRF_POWER_MODE_LOWPWR);  should not be called in power_manage as its called in a loop. As previously stated, this is done by default so you can remove this line. You should also remove the references to __WFE(); and __WFI(); as this is done by sd_app_evt_wait().

[Saram]

15,2 SDK and s132 Soft Device. Ok, remove this lines

[bjorn-spockeli]

What current consumption are you seeing after removing the the lines?

[Saram]

stayed the same. for 1 hour of work (300 ms between transfers, eddystone uid) - 0.2 volt voltage drop (on a fresh battery)