I'm in the process of designing a PCB for an RGB LED light source that will allow me to dim each color channel separately using PWM. To help manage the thermal output of the LEDs I'm trying to use an aluminum PCB substrate, and to try to keep costs in line I want to design a 1 layer board for the LEDs. The power, drivers and PWM generator will be on a separate board.
My concern is that the routing necessary to get everything on one layer involves a lot of parallel traces carrying PWM signals, and I'm worried I might end up generating some unwanted EMI. Each string of LEDs is going to be driven at a constant 200mA at a voltage which will vary from about 16V to 24V depending on the color. I'm shooting for a PWM frequency of 30-50khz.
The attached image is a schematic of my proposed routing. Will this cause EMI problems?