Electronics beginner here. I have Raspberry Pi 4 GB variant. I have the following power requirements:
- power a 5V cooling fan
12V cooling fan (a spare cooler master)thanks @Milliways
- safely (i.e. avoiding both backcharging & over-volt/amp problems) power the board via GPIOs, I have to use OTG mode sometimes so I am not using the USB-C port for charging.
How can this be done in least cost?
Inspired by @tlfong01 comment on this question, I am thinking a buying a 24v SMPS and divide its power between 1 & 2, but I don't know how to practically do it.
OTOH I already have a good fan, should I buy heat sink also?