DC/DC higher consumption than LDO

Question

Hi,

when DC/DC is enabled, current consumption in sleep is higher than when using LDO.

This is consumtion with DCDC = 0

This is power consumtion when DCDC = 1

System init

	Return_t init(void)
	{
		// Test crystals only in debug build
		#ifdef DEBUG
		_PRINT("Wait for HFXO\n");
		NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
		NRF_CLOCK->TASKS_HFCLKSTART = 1;
		while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
		NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;	
		_PRINT("HFXO started\n");

		_PRINT("Wait for LFXO\n");
		NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
		NRF_CLOCK->TASKS_LFCLKSTART = 1;
		while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0);
		NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;	
		_PRINT("LFXO started\n");		
		#endif // DEBUG

		// Configure power
		NRF_POWER->POFCON = 0;
		NRF_POWER->DCDCEN = 1;

		// Init watchdog
		NRF_WDT->CRV = (AppConfig::wdtTimeout * 32768) - 1;
		#ifdef DEBUG
		NRF_WDT->CONFIG = 1;
		#else
		NRF_WDT->CONFIG = 9;
		#endif // DEBUG
		NRF_WDT->TASKS_START = 1;

		// Enable RTC interrupt
		ret_code_t ret = sd_nvic_SetPriority(RTC2_IRQn, 2);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}

		ret = sd_nvic_EnableIRQ(RTC2_IRQn);
		if (ret != NRF_SUCCESS)
		{
			APP_ERROR_CHECK(ret);
			return Return_t::NOK;
		}

		// Enable compare0 interrupt
		NRF_RTC2->INTENSET = (1 << 16);

		// Set counter resolution of 125ms
		NRF_RTC2->PRESCALER = 4095;

		startWakeupTimer();
		return Return_t::OK;
	}
	
	void startWakeupTimer(void)
	{
		NRF_RTC2->TASKS_CLEAR = 1;
		NRF_RTC2->CC[0] = (AppConfig::measurePeriod * 1000) / 125;
		NRF_RTC2->TASKS_START = 1;
		_PRINT_INFO("Wakeup timer started\n");
	}

I expected to get better power consumption when using DC/DC. Is there reason why consumption is higher?

nRF52832 with Softdevice S132. HFXO is later requested by calling SD function.
VDD is 3V from PPK2.

EDIT:

This is consumption when MCU is running(just feeding the watchdog).

LDO

DC/DC

Is that expected?

This is HW design

Seems like DC/DC is really inefficient when in sleep.

How much DC/DC startup takes time and power? Seems like good idea to switch off DC/DC before sleep.

DC/DC higher consumption than LDO

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