I am working on something very similar to this, Adaptive LED Headlights – Model 8790 Adaptive 2 as a hobby project. I have controller part done, VID_20180728_195351.mp4, and this was the simpler part of the job.
Now I am trying to build a circuit which would light up up to five powerful LEDs depending on the lean of the motorcycle.
LEDs are Cree XPG2, they need 3.5 V and will run at ~1.5 A. The controller is ESP32 which gives 8 mA and 3.3 V. Motorcycle gives ~13.5 V and I'd like to avoid using voltage converters and keep it as simple as possible dropping 13 V to 3.5 V on transistor, power waste is not a problem since these LEDs light up only for a short periods of time.
I've tried BD135 as a switch but it cannot handle this load. Then TIP120 it's ok but in order to run at required current it requires ~4.5 V on gate.
ESP32 obviously doesn't have 4.5 V, so in order to stop burning further transistors I am looking for a way to select the right transistor for this project. I've run through many transistors datasheets but I am not sure what characteristics are important here.
On similar topics I saw that MOSFET transistors like IRF520 require 1-2 V on the base to be fully open, but I am afraid that voltage drop may not be as significant as on darlington TIP120 and it won't be possible to select an appropriate resistor between ESP32 pin and transistor's gate to have required 3.5 V at emitter.
CLARIFICATION: the system will have 10 lights in total, 5 items from each side. 1 to 5 leds may be fired at a moment depending on the lean angle.
The whole system runs on a massive aluminium heat sink(about 1 kilo) with active air flow.