CC2650: Current consumption while I2C communication with sensor

YSR1991

Part Number: CC2650

Hi,

I am using CC260 to read sensor data over I2C.

I have issue with power consumption. I am using HTU21DF sensor. While communication it takes 2.5mA current.

From datasheet of sensor measuring current is 450uA, for cc2650 I2C peripheral current is 12uA and core current Icore 1.45mA. Total (0.45+0.012+1.45=)1.912mA. My other peripherals on board are taking maximum of 10uA current. So it should show 1.922mA. But when i checked on DSO, it is showing 2.5mA. It is 578uA more current.

And is it possible that timer initialization takes more current.
Am i calculating correctly?.

Thanks in advance.

Regards,

Sharad

over 8 years ago

0 A. Rebel over 8 years ago

TI__Genius 11740 points

Hi Sharad,

On the datasheet it says: 1.45 mA + 31 μA/MHz for Active running CoreMark.
In other words, what's your clock speed? This may account for the difference. Also note, these are typical values.

How'd you find 1.45mA?

Is there a way to isolate just the components of interest? (MCU + sensor?)

Regards,
Rebel

0 YSR1991 over 8 years ago in reply to A. Rebel

Intellectual 420 points

Thank you very much A. Rebel

Calculation : 1.45mA+(31uA*24MHz)=2.194mA. ?
Active running means while communicating with peripheral through over I2C, or SPI, it switches from standby mode to active mode, i.e. it takes more current. ?? Am I correct?

I am measuring voltage across series resistor of 10E.
I have disabled advertising and only kept measurement (from sensor) running.
I will check after isolating other components on card.

Thank you.

0 Christin Lee over 8 years ago in reply to YSR1991

TI__Guru 56345 points

Yes,

I2C module runs on the high frequency clk(RCOSC_HF) which is 48MHz. To run I2C/SPI, you will have to leave standby mode.
If you want to achieve lower power consumption, you can try to use sensor controller engine for I2C communication with the sensor.

0 YSR1991 over 8 years ago in reply to Christin Lee

Intellectual 420 points

Thank you Christin Lee

Bluetooth®︎

Bluetooth forum

CC2650: Current consumption while I2C communication with sensor