BL652 vs nRF52832 DK - Current Draw Configuration Differences

[smartventSystems]

Hello,

I have been developing on a nRF52832 DK using nRF5 SDK v17.1.0, and am very close to a production ready state. The final program will use soft devices, app_timers, and multiple uart connections across peripherals and central connections. Because the final version of the hardware was supposed to run on a battery powered BL652 Laird module, I decided to try flashing it over to run tests. After I changed the sdk_config file to run the Softdevice clock on the internal RC instead of the crystal oscillator, it runs fine.

However, the current draw of the module is far more than on the development kit. On the development kit, my project runs around 0.06mA (in between radio transmissions), but on the BL652 module using a voltage regulated 1.8V, it draws closer to a steady 4 - 5mA instead! I can decrease this by using a voltage regulated 3.3V, but that still pulls around 1 - 2 mA. This is obviously still drastically more than what I was expecting, since I was using basically the same code for the development kit as the Laird module except for the clock configuration. I also don't really know why the module's current consumption would change since both voltages are within the allowed range for the module and the nRF52832 chip.

I tried running the basic ble_app_uart project example on it, and I was still getting around 4-5 mA. 

I tried running the basic blinky project example on it, and I was still getting around 2-3 mA.

So clearly, I'm doing something wrong here.

Are there any other changes that I should make in the configuration on top of the NRF_SDH_CLOCK_LF_(SRC / RC_CTIV / RC_TEMP_CTIV / ACCURACY) to use the RC clock instead to maintain proper usage on the BL652 module while keeping current draw similar to the development kit?

Does the lengthening of the radio transmission openings due to NRF_SDH_CLOCK_LF_ACCURACY really increase the power consumption that drastically?

Would switching to an external crystal oscillator really fix everything?

I copied this code over 'sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE);' without really understanding how it would impact my power consumption because I heard somewhere that it decreases current consumption on the development kit. Does this have an opposite effect on the BL652 modules?

I've attached the sdk_config that I have been using for the project development. I have been using Segger to build and run the projects. 

Any insights or help would be greatly appreciated.3223.sdk_config.h

[Simonr]

Hi

Sorry about the late reply, but I've been out of office for the last few days, and are just getting to my backlog.

Just to make sure, you set the defines I mentioned to 0 instead of 1 in your sdk_config.h file, right? 

By the GPIOs being left "open", are they in a floating state? If they are, and they're connected to peripheral devices, that might explain the current draw. As explained in the nRF52 power optimization guide I linked to earlier, the default "from reset" state of GPIOs are as disconnected inputs. Have you configured them as something else? Unused pins should be left in their default state and physically disconnected to draw no current.

Best regards,

Simon