With how cheap 100x100mm 2 and 4 layer boards are from JLC, would it make sense to separate all the voltage switching/motor pwm/battery charging/BMS on a second PCB?
My project is already going to have two PCBs, one with some sensitive analog components and the MCU, and the other PCB with a 2s2p battery charging and management circuit, and I'm trying to figure out if it would help or hurt noise to put some of the switching based components onto the battery PCB instead of the main board.
Specifically:
6V pump motor PWM control
+3.3V buck
-3.3V charge pump
+5V buck
24-30V boost
95% of the board will be running on 3.3V, with one set of sensors needing 5V, and another needing 24-30V (both very low current). Intuitively, it feels like the 6V pump PWM can be on the other board, since none of the main components will be running on 6V, but would putting the other power stuff on the second board screw with return paths and make things noisier than just having them sort of close on the same small board?