NRF54l15 current consumption increases when CONFIG_BT=y

[chcortes559123]

i am currently working on a board that is using the nrf54l15 chip. and when CONFIG_BT=n or just not included in the prj.conf i see a power consumption of about 80uA on the entire circuit, but when i set the value to Y, it jumps to 344uA. and i am trying to figure out why this is happening. anybody have any ideas? 

[Einar Thorsrud]

Hi,

I am not able to explain why just enabling CONFIG_BT=y increases current consumptoin if you do not use BT. At the same time, enabling Bluetooth whould not increase the current consumption signficantly before you start to use id (advertise/scan/connect).

How do you measure the current consumptoin? Is the numbers you wrote idle current consumption or average over some time? Do you have other components that draw current, such as logging? If so, disable UART logging.

But again, having BT just enabed in Kconfig should not matter much so I think we need to look more closely at your applcation.

[chcortes559123]

hello,

yeah this was measured using an OTii and in both cases this is an average value over time. 

the code is very simple, i made a main to talk to our LTC337 and put it in low power mode, i also disabled uart logging and uart rx, and after all that i see teh 80uA, but as soon as set CONFIG_BT=y it jumps, and nothing is calling the BLE stack. 

LOG_MODULE_REGISTER(main, LOG_LEVEL_INF);

#define LTC3337_NODE DT_ALIAS(power_monitor)
#define LTC3337_I2C_BUS DEVICE_DT_GET(DT_BUS(LTC3337_NODE))

static const struct device *const ltc3337_i2c_bus = LTC3337_I2C_BUS;

static void suspend_ltc3337_i2c_bus(void)
{
    int ret;

    if (!device_is_ready(ltc3337_i2c_bus))
    {
        LOG_ERR("LTC3337 I2C bus is not ready");
        return;
    }

    ret = pm_device_action_run(ltc3337_i2c_bus, PM_DEVICE_ACTION_SUSPEND);
    if (ret != 0)
    {
        LOG_WRN("Failed to suspend LTC3337 I2C bus: %d", ret);
    }
    else
    {
        LOG_INF("LTC3337 I2C bus suspended");
    }
}

static void configure_ltc3337_for_lowest_current(void)
{
    struct power_monitor_config cfg = {0};
    uint16_t status = 0;
    uint16_t accumulated_charge = 0;
    int32_t die_temp_mc = 0;
    int ret;

    LOG_INF("Starting LTC3337 low-power test");

    if (!power_monitor_is_ready())
    {
        LOG_ERR("Power monitor backend is not ready");
        return;
    }

    LOG_INF("Power monitor backend is ready");

    ret = power_monitor_get_status(&status);
    if (ret != 0)
    {
        LOG_ERR("Failed to read LTC3337 status: %d", ret);
    }
    else
    {
        LOG_INF("LTC3337 status REG_C: 0x%04x", status);
    }

    ret = power_monitor_get_accumulated_charge(&accumulated_charge);
    if (ret != 0)
    {
        LOG_ERR("Failed to read LTC3337 accumulated charge: %d", ret);
    }
    else
    {
        LOG_INF("LTC3337 accumulated charge REG_B: 0x%04x", accumulated_charge);
    }

    ret = power_monitor_get_die_temp_mc(&die_temp_mc);
    if (ret != 0)
    {
        LOG_ERR("Failed to read LTC3337 die temp: %d", ret);
    }
    else
    {
        LOG_INF("LTC3337 die temp: %d.%03d C",
                die_temp_mc / 1000,
                die_temp_mc < 0 ? -(die_temp_mc % 1000) : die_temp_mc % 1000);
    }

    /*
     * Lowest LTC3337 chip-current test mode.
     *
     * counter_shutdown = true shuts down the coulomb counter/current source.
     * For real coulomb-counting sleep, set this to false.
     */
    cfg.prescaler = 0;
    cfg.clear_interrupt = false;
    cfg.counter_check = false;
    cfg.counter_shutdown = true;
    cfg.adc_conv_start = false;
    cfg.alarm_level = 0xFF;

    ret = power_monitor_set_config(&cfg);
    if (ret != 0)
    {
        LOG_ERR("Failed to configure LTC3337 low-power mode: %d", ret);
    }
    else
    {
        LOG_INF("LTC3337 configured for lowest-current test mode");
    }
}


int main(void)
{
    configure_ltc3337_for_lowest_current();

    /*
     * Give deferred logger time to flush before suspending I2C and sleeping.
     */
    LOG_INF("Waiting for logs to flush before entering sleep");
    k_sleep(K_SECONDS(2));

    suspend_ltc3337_i2c_bus();

    int ret;

    LOG_INF("Entering low-power sleep");
    k_sleep(K_SECONDS(1));

    while (1)
    {
        k_sleep(K_FOREVER);
    }
}