nRF9151 - Low Power Mode

cptel

is the ‘active_sleep’ example on GITS the best example to put the nRF9151 Feather into low power mode?
what wakes it up to normal power mode given GPIO is also Disconnected?

Also, what is the difference between ‘active_sleep’ and ‘deep_sleep’ from current draw perspective? I failed to find the readme.md notes on deep_sleep example

jaredwolff

Hey @cptel

Key Differences:

Active Sleep Sample (nfed/samples/active_sleep/):

Purpose: Demonstrates ultra-low power operation while maintaining system readiness
Power consumption: <10µA (nRF9160), _5µA (nRF9151)
Functionality:
- Initializes and disables peripherals (accelerometer, SPI flash, UART)
- Configures PMIC for power optimization
- Keeps modem library initialized but inactive
- Uses Zephyr’s device power management
Configuration: More complex with modem support, image management

Deep Sleep Sample (nfed/samples/deep_sleep/):

Purpose: Demonstrates maximum power reduction by entering ship mode
Power consumption: Near-zero (device effectively powered off)
Functionality:
- Configures PMIC pulldown resistors
- Enters ship mode (requires external wake-up signal or use of nPM1300 watchdog)
- Much simpler implementation
Configuration: Includes PSM & eDRX for cellular power management

Hardware Support:

Both samples target Circuit Dojo Feather boards (nRF9151 only) with NPM1300 PMIC integration. Deep sleep does not work on the latest nRF9160 board.

Use Cases:

Active Sleep: For applications needing periodic wake-ups or quick response times
Deep Sleep: For long-term storage or infrequent sensor polling

cptel

jaredwolff how does the processor wake up from ACTIVE Sleep mode?

jaredwolff

cptel it’s the default state when the device is idle. If you start adding external circuitry, you will have to make sure it’s tuned correctly for this mode.

cptel

have you used the Nordic Power Profiler (https://www.nordicsemi.com/Products/Development-hardware/Power-Profiler-Kit-2) to measure current/profile power? Does it work with the nRF9151 Feather?

jaredwolff

cptel you can use it for anything. It’s a great option and what I use for my spot checks

cptel

which pins should the VIN and VOUT on the PPKII be connected to on the nRF9151Feather?
VUSB and 3V3 respectively?

AchimKraus

Doesn’t that depend on how you want to use the nRF9151 feather?

e.g. if you want to run it from battery, then use GND/VBAT. If you want to power it from USB, then use GND/VUSB.

The 3.3V is AFAIK an output, means you may use it to power some external devices (with care not to drain the battery). If you want to connect the PPK II here to measure the external devices, then you need to connect 3.3V ( output) to VIN (PPK II) and VOUT (PPK II) to those external device. You will then only measure their consumption.

cptel

Objective: Create a current profile of the entire device using the PPK II to select the appropriate battery size.
Assumption: I would have to connect the PPK II in-line with the main power source (USB)
Question: Are there pins on nRF9151Feather that allows me to accomplish my objective? or do I have to remove a resistor and solder couple wires to accomplish my objective?

AchimKraus

cptel Objective: Create a current profile of the entire device using the PPK II to select the appropriate battery size.

The battery will drive the device either via the JST2 or GND/VBAT. If you want to estimate the battery size, use that for power in.

Assumption: I would have to connect the PPK II in-line with the main power source (USB)

Maybe there is a misunderstanding. A battery powered device will use VBAT as main power source, not USB. USB is then only used as power source if the battery needs to be charged.
There may be other “exotic” setups, where you don’t use the “direct battery support (GND/VBAT)” of the feather, but I don’t think, you want or need that.

jaredwolff

@cptel here’s how I hook it up:

If you don’t have a JST connector with wires, you can equally connect directly to the VBAT and GND pins. I typically feed it 3.6V as that’s nominal for a LiPo battery.