I'm designing a PCB and I need a voltage rail, roughly 3 volts above the main input (of 3 - 30V). This rail is to power some CMOS devices, so it won't need to supply much current.
Currently I plan on using 2 AA batteries in series with the input, but those batteries are huge compared to the PCB so I want to get rid of them. I have searched for multiple solutions, but none match my requirements:
- Charge pumps probably won't work, because of the big voltage change in the input.
- Boost converters deliver a steady voltage, but I need an addition to the input.
- I have looked at isolated DC/DC converters, but these usually run on 5V or higher, or they are too expensive.
Do you have any ideas?
EDIT: I don't necessarily need a higher voltage. I need a stable 5v from the input. I'm not willing to use a buck boost converter, since that will take up too much space.