Power Consumption during sleep mode in NRF52832

RE: Power Consumption during sleep mode in NRF52832

Simonr — Mon, 07 Apr 2025 12:40:58 GMT

6.4mA is too much to possibly be the nRF52832 in any idle mode. Even with the CPU being left running you should see 4mA here. I'm not familiar with the EFR32, but how exactly is it used to measure current here? Do you have a dedicated power analyzer or the PPK2 for current measurement? If the nRF actually draws an average of 6.4mA, it must be the radio that is on, but in that case it seems strange that the current is as stable as it is, so I think there is some hefty leakage somewhere here.

In the ~470µA range it is, as mentioned in the bottom of the power optimization guide, likely due to a peripheral being left on, like UART logging, or SPI being kept on for example. However since there seems to be some leakage that might not be it, and I think we should start by trying to reproduce this on an nRF52832 DK if you have one available to measure on.

Best regards,

Simon

RE: Power Consumption during sleep mode in NRF52832

Thishon — Fri, 04 Apr 2025 10:31:06 GMT

I am using an EFR32 Microcontroller by Silicon Labs to measure the current by providing 3.3V supply from it to my custom board.

Logging enabled and RTT Viewer Disconnected. I am getting a sleep current of 6.4 mA. I have implemented sleep for 60s.

Still After Disabling the logs, I am getting the same current consumption.

Sometimes I am getting the current value in uA during sleep initially after flashing and power cycling.

I am unable to figure out exactly what is happening. And what is my idle sleep current consumption. I have enabled the power management and wake up source for both of my SPI Peripherals in the device tree.

&spi2 {
	compatible = "nordic,nrf-spi";
	status = "okay";
	cs-gpios = <&gpio0 11 GPIO_ACTIVE_LOW>;
	pinctrl-0 = <&spi2_default>;
	pinctrl-1 = <&spi2_sleep>;
	pinctrl-names = "default", "sleep";
	lora0: sx1262@0 {
		compatible = "semtech,sx1262";
		reg = <0>;
		reset-gpios = <&gpio0 12 GPIO_ACTIVE_LOW>;
		dio1-gpios = <&gpio0 28 GPIO_PULL_DOWN>;
		spi-max-frequency = <DT_FREQ_M(8)>;
		busy-gpios = <&gpio0 31 0>;
		antenna-enable-gpios = <&gpio0 7 0>;
		tx-enable-gpios = <&gpio0 8 0>;
		wakeup-source;
		zephyr,pm-device-runtime-auto;
	};

	zephyr,pm-device-runtime-auto;
	wakeup-source;
};

RE: Power Consumption during sleep mode in NRF52832

Simonr — Mon, 31 Mar 2025 06:25:34 GMT

Please check out our power optimization guide for some pointers on how to minimize current consumption. Optimizing Power on nRF52 Designs

It seems like a lot of steps are already mentioned by Stefan Schmidt here, but please make sure that logging is disabled, and that any peripherals that might draw power. Please also share how exactly you're measuring current in your project. Are there any other MCUs connected to the nRF52832 that might be drawing power in your design? Are the two SPI peripherals you mention connected and running for example?

Best regards,

Simon

RE: Power Consumption during sleep mode in NRF52832

Stefan Schmidt — Fri, 28 Mar 2025 14:17:06 GMT

Uh, I did not want to start a confusing: RTT uses the debugger, no uart needed here.

I mentioned the uart because I do not see your device tree/overlays and your prj.conf and wanted to give you an example where pm-device-runtime-auto is used.

When you have peripherals enabled in the device tree of your custom board or in your overlay (if you are using one), you could check if the peripherals support pm-device-runtime-auto and add the setting there

RE: Power Consumption during sleep mode in NRF52832

Thishon — Fri, 28 Mar 2025 13:49:36 GMT

I have seen somewhere that we should enable the dcdc conversion so that the microcontroller would operate in 3.3 V and the current consumption would be limited. I am not sure which uart I am using for RTT Viewer debugger. My setup contains the GND, DIO and CLK pins for flashing the custom board. I am using another NRF Dev Kit. Where should I add power management in my dts file

RE: Power Consumption during sleep mode in NRF52832

Stefan Schmidt — Fri, 28 Mar 2025 13:32:56 GMT

You can disable LOG and printk and try again.

What is the ENABLE_DCDC in your prf.conf?

You could also check that the devices in the device tree have a pinctrl set for the sleep state and that "zephyr,pm-device-runtime-auto;" is set, so that they are set to sleep after initialisation when they are not used:

debug_rs232: &uart0 {
    status = "okay";
    current-speed = <115200>;
    pinctrl-0 = <&uart0_default>;
    pinctrl-1 = <&uart0_sleep>;
    pinctrl-names = "default", "sleep";
    zephyr,pm-device-runtime-auto;
};

RE: Power Consumption during sleep mode in NRF52832

Thishon — Fri, 28 Mar 2025 13:22:21 GMT

I have already disconnected the J-Link and measuring the current using power profiler kit by powering the chip on using the kit.

RE: Power Consumption during sleep mode in NRF52832

Stefan Schmidt — Fri, 28 Mar 2025 13:20:04 GMT

Could you please retry the measurement with the J-Link disconnected? Like, phyiscally disconnected... No cable.

RE: Power Consumption during sleep mode in NRF52832

Thishon — Fri, 28 Mar 2025 13:14:22 GMT

I have added this configuration to prj.conf file:

CONFIG_LOG=y

CONFIG_PRINTK=y

CONFIG_PM=y

CONFIG_PM_DEVICE=y

CONFIG_PM_DEVICE_RUNTIME=y

CONFIG_BOARD_ENABLE_DCDC=y

Disconnecting the RTT Viewer I am getting around 1.8mA

RE: Power Consumption during sleep mode in NRF52832

Stefan Schmidt — Fri, 28 Mar 2025 13:08:39 GMT

Could you try to disconnect everything when doing the actual measurement?

RE: Power Consumption during sleep mode in NRF52832

Thishon — Fri, 28 Mar 2025 13:01:18 GMT

Yes I have RTT Viewer Connected

RE: Power Consumption during sleep mode in NRF52832

Stefan Schmidt — Fri, 28 Mar 2025 12:55:59 GMT

Hi Thishon, do you have your debugger connected to the device?