I'm designing a low-power, battery-powered sensor node using an ATtiny1626 microcontroller (1.8V~5.5V supply with low clock speed), powered directly from 2x AAA batteries (various chemistry, let's say 2V up to 3V over usable life).
For providing supply for other parts of circuit, a hi-efficiency boost converter XC9141B/42B is used. The chosen version with B suffix, bypasses the input voltage to the
VOUT pin when the
CE pin is low and the
VOUT would be more or less equal to
VBATT in that case. When the
CE goes up,
VOUT also goes up from
VBATT to 3.3V.
In order to get rid of level translations, I thought about supplying the MCU from the
VOUT pin itself; so the MCU (still powered from pass-through capability) holds the supply voltage at
VBATT and when needed, turns the boost converter on, and the supply of MCU and the other part of circuit jumps to 3.3V.
- The other parts have their own sleep modes, so it's not a problem if they still get powered by
VBATTor when the voltage jumps between values.
- The idea is to boost voltage when the battery level is low and unable to power other parts sufficiently, and maybe for better TX power of LoRA (SX1278 module.
What kind of problems would arise from this sudden switch of voltage for the MCU itself?