One key advantage of PWM is the ability to change the average output of the energy dissipated by the load by varying only the duty cycle. Systems may need a wide range luminous or thermal outputs which helps define the duty cycle range.

This is commonly referred to as the dimming ratio or contrast ratio in lightning applications. Dimming ratio, DR, is proportional to the power dissipated in a resistive element and the luminous flux of an LED.

For DIM and COLD extremes of operation, the pulse widths will be the smallest. High side switch timing limitations on minimum pulse width are used to set D_MIN and PWM frequency.