Good term between PWM and inductance to adjust led
Analog adjust led refer to adjust led luminous intensity by changing resistance .advantage: operation simply . shortcomings:The level of adjust luminous intensity is limited. In order obtain to more effect level of adjust light. We adopt inductance and PWM to adjust light. The theory as follows:

PWM through changing duty cycle to control that the conduct time of LED. The PWM can adjust multi-level led light. And inductance is energy storage component . in electrical circuit, inductance can product magnetic field when input current into inductance. The energy will release in PWM is Closure period It can not only become asset current for LED. but we need to make sure that the cycle of pwm is small than conduct time of inductance.