Chapter 19. PWM Drivers

Pulse Wide Modulation (PWM) operates like a switch that constantly cycles on and off. It is a hardware feature used to control servomotors, for voltage regulation and so on. The most well-known applications of PWM are:

• Motor speed control
• Light dimming
• Voltage regulation

Now, let's introduce PWM with a simple diagram:

The preceding figure illustrates a complete PWM cycle, introducing some terms that we need to clarify prior to getting deeper into the kernel PWM framework:

• Ton: This is the duration during which the signal is high.
• Toff: This is the duration during which the signal is low.
• Period: This is the duration of a complete PWM cycle. It represents the sum of the Ton and Toff of the PWM signal.
• Duty cycle: This is represented as a percentage of the time signal that remains on during the period of the PWM signal.

The different formulas are detailed as follows:

• PWM period:
  
• Duty cycle:
  

Note

You can find details about PWM at https://en.wikipedia.org/wiki/Pulse-width_modulation...