Regrading Sleep current in nrf52840

RE: Regrading Sleep current in nrf52840

Santhosh_123 — Wed, 24 Nov 2021 06:14:27 GMT

Hi Kazi,

Yeah we tried with both source and ampere mode but we are not getting desired value. We also checking with the setup from our side we will update you soon ASAP

RE: Regrading Sleep current in nrf52840

Kazi Afroza Sultana — Tue, 23 Nov 2021 11:49:53 GMT

Hello Santhosh,

Trying source mode with power analyzer provides the desired value ?

Kazi

RE: Regrading Sleep current in nrf52840

Santhosh_123 — Tue, 23 Nov 2021 06:00:48 GMT

Hi Kazi,

Sorry for wrong information

we are not getting for sleep current what is in the datasheet But for CPU running it coming what is in the datasheet

RE: Regrading Sleep current in nrf52840

Kazi Afroza Sultana — Mon, 22 Nov 2021 15:26:41 GMT

Hello Santhosh,

Any current measuring device that can accurately measure down in the uA should be ok with measuring current. Unfortunately we do not have official documentation of measuring current by power analyzer.

However, You can try using source mode of your power analyzer which will power the board on the external header and will measure current simultaneously. The DK setup will be same as I mentioned before.

''You can find a switch (SW10) on the PCA10056 where you can choose to supply nRF52 directly using the supply header. This switch is called VEXT-> nRF. So if you now connect the PPK to the external supply header, flip this switch, and leave the USB connected to power the rest of the board, you should be powering the nRF52 from the PPK. You also have to turn the switch (SW6) to nRF Only from DEFAULT to avoid the leakage current. Also remember to reset the board or power on and off after flashing.

Try this and see what would be the outcome.

Best Regards,

Kazi Afroza Sultana

RE: Regrading Sleep current in nrf52840

Santhosh_123 — Mon, 22 Nov 2021 07:19:06 GMT

hi Kazi,

Our team went into what you said. But we don't have PPK kit for current measurement then what to do if we want to measure the sleep current?

Same method we followed for the CPU running

ICPU0 CPU running CoreMark @64 MHz from flash, Clock = HFXO,Regulator = DC/DC --> 3.3 mA

we got 3.3mA what is in the datasheet without PPK Kit By using this example code

nrf-NRF52840\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\peripheral\flashwrite

Now for sleep current we are following this example code

nrf-NRF52840\nRF5_SDK_17.1.0_ddde560\nRF5_SDK_17.1.0_ddde560\examples\peripheral\ram_retention

IOFF_RAMON_RESET System OFF, full 256 kB RAM retention, wake on reset 1.86 μA

But we are getting what is given in the datasheet

RE: Regrading Sleep current in nrf52840

Kazi Afroza Sultana — Wed, 17 Nov 2021 10:01:52 GMT

Hello Santhosh,

The example code will be like this -

void main(void) {

for(;;) {

void main(void){ for(;;){

__WFE();

}

When we are talking about RAM retention, we mean that the RAM is retained when the chip is in System OFF mode. But when the system is ON, all RAM is always retained (powered on) unless explicitly power down in code. So basically the above code put the CPU in sleep mode (WFE = Wait For Event).

Best Regardds,

Kazi Afroza Sultana

RE: Regrading Sleep current in nrf52840

Kazi Afroza Sultana — Tue, 16 Nov 2021 10:44:20 GMT

Hello Santhosh,

You can measure current in two ways, either using source meter mode or ampere meter mode (Nordic Semiconductor Infocenter). The problem with the source meter mode is that you have to make sure that you are not powering the rest of the board ( debugger chip etc) with the Power profiler kit (PPK). The problem with ampere mode is that there is noise on the current measuring header which leads to 5-10 uA current leakage.

You can find a switch (SW10) on the PCA10056 where you can choose to supply nRF52 directly using the supply header. This switch is called VEXT-> nRF. So if you now connect the PPK to the external supply header, flip this switch, and leave the USB connected to power the rest of the board, you should be powering the nRF52 from the PPK. You also have to turn the switch (SW6) to nRF Only from DEFAULT to avoid the leakage current. Also remember to reset the board or power on and off after flashing.

Could you please try this first and see what will be the current afterwards?

Kazi Afroza Sultana

RE: Regrading Sleep current in nrf52840

Santhosh_123 — Tue, 16 Nov 2021 10:05:37 GMT

Hi kazi,

Thank you for your reply,Yeah for this \nRF5SDK\17_0_2\d674dde\examples\ble_peripheral\ble_app_pwr_profiling

we are getting 0.3 uA then i think setup is of But

we want to measure the sleep current for this specification

ION_RAMON_EVENT System ON, full 256 kB RAM retention, wake on any event 2.35 μA

any example code is there for this?

RE: Regrading Sleep current in nrf52840

Santhosh_123 — Tue, 16 Nov 2021 04:54:46 GMT

Hi Kazi,

Thank you for your reply

Board Model - NRF52840(PCA10056)

RE: Regrading Sleep current in nrf52840

Kazi Afroza Sultana — Mon, 15 Nov 2021 15:07:38 GMT

Hello,

I need the picture of your set up, board details.

You can build the example app_ble_pwr_profiling from \nRF5SDK\17_0_2\d674dde\examples\ble_peripheral\ble_app_pwr_profiling in SDK 17. It should measure 0.3-0.4 uA. If it does so then we know that the setup is ok.

Kazi

RE: Regrading Sleep current in nrf52840

Santhosh_123 — Mon, 15 Nov 2021 12:25:25 GMT

Hi,

As part of debugging we tried to measure if any leakage current in the DK. We measured the DK current by providing external supply on P21 and switching OFF the power switch(SW8). To our surprise even when the power switch is in OFF mode we are measuring 4.6uA of leakage current.

When we subtract the 4.6uA leakage current with 5.23uA measured current, we get 0.6uA, which is also not as expected.

Please add your insights on how to avoid the leakage during switch OFF and help us resolve the same.

Thanks

Santhosh

RE: Regrading Sleep current in nrf52840

Kazi Afroza Sultana — Mon, 15 Nov 2021 12:22:33 GMT

Hello Santhosh,

Could you please tell us what board exactly you are using?

BR
Kazi Afroza Sultana

RE: Regrading Sleep current in nrf52840

Santhosh_123 — Mon, 15 Nov 2021 10:43:51 GMT

can any one please reply for ths