Low Power PWM Consumption

[LukeC]

I am working with the SDK 12, nrf52832 low_power_pwm example. I am concerned about the power consumption I am measuring.

I am trying to produce a 1khz PWM for an LED (the device I am working on is moving so the PWM needs to be fast enough not to see any pulsing when moved).

I am measuring ~112uA when in sleep calling __WFE (duty cycle is zero, this is just overhead for the pwm)

I believe the low_power_pwm is waking from sleep every period which is causing this high current. Is there a way to keep this library from triggering a wakeup?

[Sigurd]

Hi,

Try to turn off the PWM before you go to to sleep, using the function low_power_pwm_stop(&pwm_instance)

[LukeC]

Thanks, but in my application I need to have the LED on while running, I am trying to get the lowest sleep current possible while PWMing the LED.

[Sigurd]

With the low power PWM running at 1 kHz, I don't think you can get it much lower than your 112 µA. I think the CPU goes from IDLE mode to RUN mode every pwm period to switch the GPIO level, so with increasing frequency the current consumption goes up. If you reduce the frequency, the current consumption should go down.