Raspberry Pi Pico power saving usage examples:
- Sleep mode
- Underclock
- Hybrid
Lowest achieved consumption without using sleep mode (underclock) is around 5.5 mA. Deep sleep achieves around 2 mA.
Minimal clock achieved for Rasperry Pico was ~15MHz.
Raspberry Pico documentation is amazing. Check chapters Power Control and Clocks of RP2040 datasheet for a better understanding of MCU internals.
For clocks,
- pico-sdk API - hardware_clocks
- pico-sdk API - hardware_vreg
- pico-examples by hermann
- Watch hang and multi-hang exampes. Help to understand valid clock configurations.
- Original post Link
For deep sleep,
Record low underclocked non-sleep current consumption of 4.5 mA was observed when +5V was connected to VSYS rail instead of VBUS one to evade Shottky diode which adds some power loss by itself. But please pay attention: your mileage may vary because of manufacturing variations. Also you will lose reverse polarity protection in this case.