High IDLE current on nRF52832

RE: High IDLE current on nRF52832

MartinBL — Thu, 26 Oct 2017 16:10:11 GMT

Glad you figured it out. A workaround can be found in the documentation of PAN 87.

RE: High IDLE current on nRF52832

Otavio Borges — Thu, 26 Oct 2017 11:55:50 GMT

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.

RE: High IDLE current on nRF52832

Otavio Borges — Thu, 26 Oct 2017 11:50:49 GMT

Checked the pulldown confĩguration, but none of the GPIOs were responsible for the high current. Turns out the FPU was being kept running. I've posted an answer detailing the issue. But still a good reminder.

RE: High IDLE current on nRF52832

MartinBL — Thu, 19 Oct 2017 10:04:09 GMT

Hi. User @a.o. has a point below. The value of the pull resistors in the nRF52 is typically 13kOhms. Hence, a pull-up being pulled low, or a pull-down being pulled high will typically draw ~3V/~13kOhm = 230uA. Dependent on your supply voltage of course.

RE: High IDLE current on nRF52832

a.o. — Wed, 18 Oct 2017 16:08:06 GMT

I had a high idle current on one of my projects of around ~200uA and I believe the cause was that a pull-up had been active on a pin that was externally pulled low.