Turning off peripherals before sleep mode (System ON)

[ZR7]

Hi,

Is there an example code for nRF52832 were the system is configured to operate in a certain duty cycle, e.g. performing a certain task once every 100ms, and then goes to sleep mode, but where the current consumption during sleep mode is below 500uA? 

I was using sd_app_evt_wait(); to enter sleep mode, but this by itself doesn't bring me to low current. I still have around 7.5mA consumption. 

Thanks

[ZR7]

Hi Simon,

I built the timer example and loaded into by evaluation board (I am using Rigado BMD-350 EVK). I used the instructions on their manual to measure current and the current was around 610 micro Amps. I used an oscilloscope and tried to distinguish between the time the LEDs are ON and OFF, in case the LED current is taken into account, but I didn't see a big difference, so I concluded that the LED current is not included in the measurement. 

Is this the expected current consumption in the Timer example? It is much higher than the System ON sleep current that I was expecting. According to the data sheet, it should be below 2uA. 

For the test, I disconnected the USB cable and power cycled the system. In the debugger I used the option "build and run". 

Can you tell me if I did something wrong, or how can I further reduce the current?

Thanks

Zvi

[Simonr]

Yes, the Timer example is not optimized in terms of current consumption, and ~400uA is the current consumption of only the timer peripheral running. This example is only to see how you can use the Timer peripheral at all.

It is indeed much higher than the system ON sleep mode, as the device is not asleep in this case, but awake and running a peripheral. For the lowest current consumption while sleeping (with a timer as wakeup) I would suggest checking out the RTC peripheral. This case has a code example showing how the RTC can be used to control the sleep and reach ~2uA.

Best regards,

Simon