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  • Case ID: 126059
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High IDLE current on nRF52832

Otavio Borges

Hello all,

During current measurements of our product using nrf52832QFAAB0 I've noticed a high IDLE current of ~450uA. Trying to isolate the problem we programmed our board with ble_app_beacon example from SDK 14.0.0 and Soft Device s132 5.0.0 obtaining the same IDLE currrent.

Including sd_power_dcdc_mode_set(NRF_POWER_DCDC_ENABLE) (on the end of ble_stack_init()) reduced the IDLE currrent to ~275uA. A value still quite above the one described on devzone.nordicsemi.com/.../.

We've run some tests on a board with minimal circuitry, as described on section 53.2 from the nRF52832 Product Specification v1.3, getting the same ~275uA.

Browsing the forum I stumbled on [156] GPIOTE: Some CLR tasks give unintentional behavior but I not sure if it's applicable, since ble_app_beacon does not use GPIOTE.

I've used an Oscilloscope, an instrumentation AmpOp and 1 ohm shunt resistor to read the lower currents. And have validated the minimum precision by measuring the current of a device on System OFF mode, on this mode the reading was ~2uA.

Is there any other configuration missing from the ble_app_beacon to reduce the power consumption or any other bug that could be causing this high IDLE current?

Thank you.

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  • 0

    Turns out, after SAADC successful conversion I used the FPU to calculate the voltage drop on the battery. As described in devzone.nordicsemi.com/.../ there's a bug on nrf52 that, even disabling the SAADC peripheral, the FPu is kept alive holding the CPU to go on sleep mode.

    I've removed the floating-point operation and IDLE current dropped-down to around 5~10uA. Considering the others ICs on the board that value is within expected range.

    Nevertheless, is there a workaround from nordic to address this issue? Or a way to manually turnoff the FPU?

    Thank you all for the help.

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  • 0

    Turns out, after SAADC successful conversion I used the FPU to calculate the voltage drop on the battery. As described in devzone.nordicsemi.com/.../ there's a bug on nrf52 that, even disabling the SAADC peripheral, the FPu is kept alive holding the CPU to go on sleep mode.

    I've removed the floating-point operation and IDLE current dropped-down to around 5~10uA. Considering the others ICs on the board that value is within expected range.

    Nevertheless, is there a workaround from nordic to address this issue? Or a way to manually turnoff the FPU?

    Thank you all for the help.

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