I'm working on an art project that consists of ~180 LEDs with about a dozen fading/flashing PWM patterns, with each pattern group/circuit controlled by a PN2222A transistor on the cathode side, with the transistor bases' signals coming from a microcontroller.
I would like to be able to control the overall brightness of all LEDs simultaneously (not really possible via the microcontroller with how I've programmed it), so I had the idea to use a few leftover transistors connected in "parallel" on the anode side to create a PWM brightness controlling "main bus" for all LEDs. The PN2222A transistors I'm using are rated up to 2A, so I figured putting 2-3 in parallel would allow the control of the LEDs high current draw (~3.6A @20mA each):
I'm wondering if this looks like a reasonable solution? Or is there some reason not to do this in favor of a better way? Thank you very much!