large current consumption in nrf52 in sleep mode

[Ankush]

Hi,

I am using BMD300 rigado board having nrf52. In my application i am tracking the ADXL362 accelerometer's motion.For this, I am combining SPI, UART(for displaying data in terminal) and some GPIO pins(Buttons and LEDs).

After all initialization in while(1) loop, i am putting the device in sleep mode using __WFE(); __SEV();__WFE(); In sleep mode, I am getting current consumption 362 uA. When Activity interrupt occurs it raises to 2.72 mA and after inactivity interrupt it goes to sleep mode again.

If I simply put device in sleep mode in normal code disabling all functionalities, current consumption is 19uA. I have set DCDCEN in the code.Does it make any difference?

Can any one tell me why this happening? Please give any suggestions.

[Keton]

UART is high power consumption peripheral as it keeps HFCLK running. Disable it before entering sleep cycle. Same most likely is true for SPI.

[Ankush]

Hi Keton,

Thanks for your reply. It works for me.Now i am trying by disabling the UART and current consumption is approximately 19 uA(which I needed). But if we consider the datasheet values of nrf52, its still very high. In datasheet is given as nearly 2 uA. Why there is so difference? Is it because of the BMD300 RIGADO board?

[Keton]

Ankush according to this: devzone.nordicsemi.com/.../ 19uA is a very good result.

[gnrboy]

Im using BMD300 module and using from nordic uart example ble_peripheral_uart (pca10040 nrf52832(bmd300)) in example after 3 minutes if any device doesnt connect to bmd300 it goes in sleep. In sdk_config are enabled external 32 kHz crystal. When device is in sleep average current which i mesure with otti is 11 mA