I encountered a mass produced device that has a power circuit like this:
5V from USB ==[boost converter]==> 13V ==[buck converter]==> 12V
and it confused me. I don't see why you would need a buck converter there.
The 13V rail is connected only to the buck converter, and nothing else. I think you can just set the boost converter to output 12V and omit the buck converter altogether, because power input is from USB and there's no need to drop voltage down (under normal circumstances). Or, if noise is a concern, you might use an LDO in place of the buck converter. However in case of this device the 12V rail is fairly noisy.
What is advantage(s) of this boost+buck configuration, over a single boost converter or a boost+LDO configuration?
EDIT: adding schematic which I reverse-engineered from the PCB, picture follows:
Note: the other side of the PCB is a ground plane. No traces there.