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NRF52832 Current Consumption

KellyJust

I am looking to figure out my current consumption with an NRF52832 chip. I have the NRF chip running at 3V using UART, SAADC, BLE and SPI. The chip is constantly reading some sensors and is connected to nrf connect app all the time but only sends sensor data after intervals of 15 minutes. From my understanding looking at the data sheet. 

LDO Mode: 

CPU current of 7.4mA

Not sure of the Radio current as the chip is sitting idle from a BLE communication perspective but is still maintaining the connection to the mobile and has TX current every 15 minutes. So, I would assume RX current of 11.7mA is being drawn just to maintain the connection. Plus adding on UART etc a total of maybe 20mA.

DCDC Mode

Assuming same as above CPU 3.7mA and an RX current of 5.4mA.

Want to see if my calculation and assumption for current consumption are correct.

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  • +1

    During a BLE connection the TX/RX pair is scheduled in intervals (called "connection interval") and they are on for just a few milliseconds at a time. RX is not running continuously. The average current will depend on the connection interval. If you are not sending any data, or don't need to have a low latency data transmission, you can use a very long connection interval and the average current will be in the 10 uA range, just for maintaining the connection. Check out the BLE power calculator: https://devzone.nordicsemi.com/nordic/power/w/opp/2/online-power-profiler-for-ble

    Not sure what you application is doing but a 100% CPU usage seems very intense. The CPU is going to idle mode when not being used (place WFE (wait for event) in the main loop), and consume about 2 uA. The timing of the sensor sampling is usually handled by the RTC timer (running of the 32.768 kHz LF clock), or the TIMER peripheral (running of the 32MHz HF clock, for better accuracy). RTC and TIMER run currents are approximately 1uA and 0.5mA respectively. The run current of the CPU is 7.4mA (LDO) but it's usually running just a fraction of the time.

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  • +1

    During a BLE connection the TX/RX pair is scheduled in intervals (called "connection interval") and they are on for just a few milliseconds at a time. RX is not running continuously. The average current will depend on the connection interval. If you are not sending any data, or don't need to have a low latency data transmission, you can use a very long connection interval and the average current will be in the 10 uA range, just for maintaining the connection. Check out the BLE power calculator: https://devzone.nordicsemi.com/nordic/power/w/opp/2/online-power-profiler-for-ble

    Not sure what you application is doing but a 100% CPU usage seems very intense. The CPU is going to idle mode when not being used (place WFE (wait for event) in the main loop), and consume about 2 uA. The timing of the sensor sampling is usually handled by the RTC timer (running of the 32.768 kHz LF clock), or the TIMER peripheral (running of the 32MHz HF clock, for better accuracy). RTC and TIMER run currents are approximately 1uA and 0.5mA respectively. The run current of the CPU is 7.4mA (LDO) but it's usually running just a fraction of the time.

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