You have it right. Many cheap always-connected smart devices use Low-dropout regulator (LDO). What does wiki say about these? > The advantages of an LDO regul

You have it right. Many cheap always-connected smart devices use Low-dropout regulator (LDO). What does wiki say about these? > The advantages of an LDO regulator over other DC-to-DC voltage regulators include the absence of switching noise (as no switching takes place), smaller device size (as neither large inductors nor transformers are needed), and greater design simplicity (usually consists of a reference, an amplifier, and a pass element). The disadvantage is that, unlike switching regulators, linear DC regulators must dissipate power, and thus heat, across the regulation device in order to regulate the output voltage. See for example: https://templates.blakadder.com/athom_PG01EU16A.html https://templates.blakadder.com/athom_PG01EU16A.html You can clearly see an AMS1117 (a super popular LDO), right next to the ESP board on lower right. Most LDOs have a chunk of metal tinned to the board so that the copper layer can help with heat dissipation. You can quickly identify them by this design. Here is another one on a dev board: https://hallroad.org/images/watermarked/thumbnails/465/465/detailed/24/Espressif_ESP32_WROOM_32D_Development_Board.jpg https://hallroad.org/images/watermarked/thumbnails/465/465/d... More on the topic: https://www.digikey.com/en/articles/use-adjustable-low-leakage-ldos-to-extend-battery-life-in-wearable-designs https://www.digikey.com/en/articles/use-adjustable-low-leaka...