nrf52840 high power consumption 0.92 mA system on with app_timer running

[Yogeshwaran]

i am testing nrf power consumption using amper testing method and example which i am using was ble_app_uart. i modified the example by adding app_timer and removed sleep, so after adv timeout the device will be idle till app_timer expires. when app_timer expires it again start advertising but when i am measuring current in idle mode it was too high(0.92 mA).

can you tell what part of the peripheral i have to switch off and how to run low power with app_timer running and i am not using any peripheral.

[Simonr]

Hi

What kind of circuit board is your chip on? Is it the Development Kit or a custom board? If you are using a chip with the DC/DC regulator parts, you should make sure that the DCDC is enabled. Also, please make sure that the UART peripheral is disabled when it isn't in use, and make sure that you don't have any floating pins, as they might be causing excessive current draw.

Best regards,

Simon

[Yogeshwaran]

i am using NRF-DK DCDC is also enabled but the problem is interface MCU is still powered using USB. if i am running ble_app_uart example in external power the device hanging(one led blink) and after this nothing i could see. if i upload ble_app_blinky it was working perfect with external power and the only modification i made in ble_app_uart was the app_timer of about 20 sec.

i could not understand the difference of ble_app_blinky and ble_app_uart which is not running in external power with app_timer

[Simonr]

Hi

Well, the big difference is that one is that the blinky application doesn't use the UART peripheral. The reason it hangs in external power mode, is likely due to the UART not being connected to anything so it isn't able to do the UART task. Could you have a look at this link which explains how to measure current with external power supply.

Best regards,

Simon

[Yogeshwaran]

yeah now uart i disabled and everything is fine but still average current in sleep was 0.5 mA. in sleep_mode_enter() i want to switch off ble radio and is there any other peripheral should turn off to get around 5-10 uA sleep current.

[Simonr]

Hi

See this link. It explains just about every way for how to reduce current consumption.

Best regards,

Simon