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Low power with peripherals, I2C and SPI in nrf52

JoseSecmotic2

Hi everybody, We are using a custom board based in nrf52832, BLE and a custom antenna, and we are finding some issues trying to use the device in low power mode. We are using I2C and SPI communications and we have the following set of sensors:

Accelerometer gyroscope and magnetometer (BMX055 from Bosch: datasheet) Ultraviolet sensor (SI1133 datasheet ) Gas gauge / battery monitor datasheet

We have tried putting the sensors in their low power mode, and our objective is having a mean current consumption of 500uA.

We are using the softdevice s132 with the SDK v13 and even trying to use System OFF / System ON to minimize the consumption. Using this we have achieved 1uA / 100uA in the development board, but the minimum current we have achieved in our custom board is of 5mA (non acceptable) We have discarded a hardware problem Here is our very basic code, where we have achieved the minimum power in the custom board. Any help would be appreciated!

main.c

Thanks in advance

Edit:

We have done the following:

  • Put the UV sensor in deep suspend mode. Now the system consumes 2mA~
  • We have tried to use SystemOFF instead of SystemON and the result is that the system consumes about 1,6~mA, (-300 - 400 uA), so it makes sense that the CPU is running correctly. What else could it be?
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  • 0
    1. Can you try the plain ble_app_template example from our SDK and measure the current?
    2. Even the most trustable parties have a certain failure rate of their products. We can't even rule out a faulty nRF52 chip. The device might have been damaged during shipping too.
    3. In your main.c file it looks like the sensors are just being initialized. Is it so that they are not being used and not supposed to draw any power?
    4. Are you able to get a picture of the current plotted over time? Current spikes and patterns can give us a clue of what it is that draws current.
    5. Unless you are transmitting or receiving data continuously it is very unlikely that the nRF52 draws 12mA alone.
    6. If you have it, can you upload the schematics and PCB layouts? You can do it in private if you open a support case in MyPage.
Reply
  • 0
    1. Can you try the plain ble_app_template example from our SDK and measure the current?
    2. Even the most trustable parties have a certain failure rate of their products. We can't even rule out a faulty nRF52 chip. The device might have been damaged during shipping too.
    3. In your main.c file it looks like the sensors are just being initialized. Is it so that they are not being used and not supposed to draw any power?
    4. Are you able to get a picture of the current plotted over time? Current spikes and patterns can give us a clue of what it is that draws current.
    5. Unless you are transmitting or receiving data continuously it is very unlikely that the nRF52 draws 12mA alone.
    6. If you have it, can you upload the schematics and PCB layouts? You can do it in private if you open a support case in MyPage.
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