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    BNO055 draws 70mA in config mode

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    BNO055 draws 70mA in config mode

    Good afternoon

    I recently developed a firmware for a gadget and I used a BNO055 breakout board from Adafruit during the development stage. The code works fine on this breakout board. Now I made my own pcb with the BNO055 on it and I am still abe to set the power mode and operation mode and read out the euler angles but when I change into the config mode, the BNO055 draws 70mA and obviously is getting warm... The reason why I switch into the config mode is beause I want to set the BNO055 in suspend mode which works fine on the breakout...

    I attached the schematic of the pcb, is there a mistake on the pcb? C_VDD is 3.3V (the pull up resistors are on another pcb and I am using 10k resistors.)

    Thanks for your feedback

     

    Anmerkung 2020-05-15 113137.png

     

    Michael

     

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    5 REPLIES 5
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    Community Moderator

    Re: BNO055 draws 70mA in config mode

    The following is one example schematic of BNO055 chip with I2C also.

    For your reference.

    From you schematic,  i will say, the 10K pull down register  (R17, R18,R19) are not necessary.  you can use 0 ohm register directly.

    Pin 8 and pin 7 should be connect to GND if you are not using them.

     

    2020-05-15_16h33_38.jpg

     

     

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    Re: BNO055 draws 70mA in config mode

    Hello

    Thanks for your reply. I changed R17, R18 and R19 to 0 ohms and it still draws 77mA in config mode. The datasheet says Pin 7&8 "do not connect" thats why I left the pin floating. 

    Are there any other ideas?

    kind regards

    Michael

    Highlighted
    Community Moderator

    Re: BNO055 draws 70mA in config mode

    What is the current consumption for  working mode  (NDoF mode or any other fusion mode you selected) on your board right now?

    Please read back the register content and compare with the default value and your set value to see if all register has the correct content inside.

    If it is still current leakage,   we need to indentify which pin cause this current,  then we might need to cut off each pin to isolate the problem first. 

    Highlighted

    Re: BNO055 draws 70mA in config mode

    Hello, 

    I just realized that the external oscillator was not placed the right way on the pcb so that the pin26 and pin27 was short cutted the whole time. The BNO055 still works fine in NDOF Fusion mode and draws around 12mA which is totally fine. But now I am not sure if the BNO could be damaged. But in my opinion it is still strange that the current draw rises up to 80mA when I switch to config mode. If I set the Adafruit breakout board into the config mode it draws around 8mA with the same code...

    Do you think the BNO is damaged because of the shortcut between pin26 and pin27?

    king regards 

    Michael

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