nRF5340-DK Current Measurement Problems

RE: nRF5340-DK Current Measurement Problems

runsiv — Wed, 29 May 2024 07:45:11 GMT

No worries, happy to help. Best of luck on the development

Regards

Runar

RE: nRF5340-DK Current Measurement Problems

secondbest — Wed, 29 May 2024 07:25:27 GMT

Hi Runar, I feel that my current settings are good enough to continue. Thanks a lot.

RE: nRF5340-DK Current Measurement Problems

runsiv — Tue, 28 May 2024 12:49:32 GMT

I ran your numbers through one of our experts on power consumption just to be sure. 4.3µA on idle if you got full RAM retention on both cores is good. The idle current in the PS is a typical value so some device to device variation is to be expected. Just to make sure you have no offset in your measurement, you can try to put the device in system OFF, and if you then measure over 1µA you will know you have some offsett in the measurements.

If you need a lower current draw, it it might be possible to run your application with less RAM as RAM retention as most of the leakage in idle is from the RAM retention.

Regards

Runar

RE: nRF5340-DK Current Measurement Problems

secondbest — Mon, 27 May 2024 09:17:35 GMT

Hello,

I make measurements at in power mode again. Switch positions are

VEXT->NRF SWITCH = OFF

NRF ONLY | DEFAULT SWITCH = NRF ONLY

My board consumes 16.3uA at your suggested case. I make measurements again for other case.

(section 6.2) --> 8.9uA

If I remove P22 header, the power consumption decreases to 5.4uA. I feel that smt on my boards consumes 5.4uA.

(section 6.3) --> 4uA

I don't know what I do wrongly.

Thanks.

RE: nRF5340-DK Current Measurement Problems

runsiv — Fri, 24 May 2024 08:03:27 GMT

Could you try to do the measurement in power mode? Power mode will reduce the amount of USB noise induced into the system

Just remember to match the supply voltage to VDD so you don't get any leakage

It's not necessary to use NRF ONLY | DEFAULT SWITCH = NRF ONLY

Regards

Runar

RE: nRF5340-DK Current Measurement Problems

secondbest — Wed, 22 May 2024 14:51:17 GMT

Hello,

Thank you for very quick response.

To start with I am wondering if you have prepared the DK as described here.
>>> Yes. I prepared board as described.

Could you also show me your BLECentralScan function? I'm wondering if maybe something spawned another thread since I can't see anything else in your main that should indicate that it wakes up every second.
>>> You are completely right. I solved this one second ticking problem. I am so sorry. My new idle current is 4.3uA. According to online power profiler, it must be 3.1uA. Difference between these two results are expected or not.

(Idle current while application and network core active. Both cores DCDC converters are enabled.)

BleCentralScanner.cpp

int BLECentralScan::Init(void)
{
	int err;

    uint16_t size = sizeof(scanner_data_t);
    ATM_LOG_INF("Size of scanner item: %d-byte", size);
	__ASSERT((size%4)==0, "Scanner item size is not devidable by 4.");

	err = bt_enable(NULL);
	if (err) {
		ATM_LOG_INF("Bluetooth init failed (err %d)\n", err);
		return err;
	}
	
	bt_conn_cb_register(&conn_callbacks);

	bt_addr_le_t addr = {0};
	size_t count = 1;
	bt_id_get(&addr, &count);

	static char mac_str[18];
	sprintf(mac_str, "%02X:%02X:%02X:%02X:%02X:%02X", addr.a.val[5], 
													  addr.a.val[4], 					
													  addr.a.val[3], 
													  addr.a.val[2], 
													  addr.a.val[1], 
													  addr.a.val[0]);

	ATM_LOG_INF("Bluetooth initialized. MAC: %s", mac_str);	
	return 0;
}

I would suggest trying one of our samples to see if you see the same behaviour.
>>> Ticking problem is solved. I am not seeing any peak while both core are active and at the idle state.

It could also be worth having a look at this old blog for inspiration.
>>> I will check it. Thanks for the suggestion.

Thanks.

RE: nRF5340-DK Current Measurement Problems

runsiv — Wed, 22 May 2024 12:35:51 GMT

I will look into your case.

To start with I am wondering if you have prepared the DK as described here

I would suggest trying one of our samples to see if you see the same behaviour.

Regarding your last part, I would start by preparing the DK before doing anything else

It could also be worth having a look at this old blog for inspiration. However it seems to me you have an idea of what to do

Regards

Runar