A simple Buck converter to drive/control LEDs.
It will Step down 7.4 V from a 2S LiPo to the needed Voltage. A 3S LiPo (11.1 V) is another possibility.
The Current is measured through the drop in Voltage over the 0.1 ohm resistor (shunt).
A Microcontroller measures the current (voltage drop) and controls the PWM width using PID to adjust the output Voltage. PID is a control mechanism which tries to reduce the error between a target and a measured value.
The use of a MCU makes it possible to set different currents and allows smooth dimming. Most of the MCU's resources will be unused and can be used for different tasks.
In this circuit the target current is 1.5 A. The nominal current of the LED is 2 A.
