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I am thinking how to best (best=lowest energy consumption and standby current) power a STM32WLE: https://www.st.com/en/microcontrollers-microprocessors/stm32wlex.html

The power management of the IC itself is described on p23 onwards, the MCU accepts from 1.8-3.6V.

My constraints are:

  • I want to power an external hall effect sensor with a stable voltage (let's say 3.3V).
  • As battery, I would like to use a LiPo but it is not a must.
  • Standby current should be less than 50µA
  • Max current pulled will be 200mA

I have been thinking about following implementations:

  1. Texas is offering a few nice buck or buck/boost converters such as these ones here: https://www.powerelectronicsnews.com/diy-how-build-a-smart-power-supply-for-your-microcontroller-projects/ . If I use a buck/bost converter, I am not so limited to the battery chemistry. What do you think?
  2. Here someone has tried using just a couple of forward biased silicon diodes to reduce a 5V input signal but it just seems wrong when going for lowest power consumption: https://www.allaboutcircuits.com/technical-articles/a-low-cost-method-of-powering-a-microcontroller/
  3. Previous thread here from stackexchange: Most efficient way to convert from 3.5-4.2V (singe cell LiPo) to stable 3.3V for currents up to 500 mA? Buck converters are suggested there
  4. The LTC3440 has a quiescent current of around 25µA, which sounds fair: https://www.analog.com/en/technical-articles/it-just-got-easier-to-convert-lithium-ion-battery-voltage-to-33v.html#
  5. I guess I can just browse for low-quiescent current buck/boost converters.

EDIT: My question is: Can you review my ideas for implementing an energy-efficient power supply for a microcontroller?

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  • \$\begingroup\$ @Transistor Alright, edited it. \$\endgroup\$ Feb 27, 2021 at 14:41

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