Join our subscribers list to get the latest news, updates and special offers directly in your inbox
Overview
What is PWM?
Pulse width modulation (PWM) is a method used in electronics to control the power output of a circuit by modulating the width of a pulse signal. In PWM, a fixed frequency electrical signal, often a square wave, is turned on and off at a rapid rate, and the width of the "on" part of the duty cycle is varied to achieve the desired output.
Duty Cycle of PWM :
The duty cycle of a PWM signal is a measure of the proportion of time during each cycle of the signal that the signal is in its "on" state, which is typically a high voltage state. Essentially, the duty cycle is the fraction of time that the signal is in its "on" state relative to the total time of the signal cycle, expressed as a percentage. For instance, if the duty cycle is 50%, the signal is in its "on" state for half of the signal cycle duration.
Turn on Time
Duty Cycle = ---------------------------------------
Turn On Time + Turn Off Time
Process for generating the pulse width modulation :
To generate a pulse width modulation (PWM) signal, a comparator is used. The comparator has two inputs - one is the modulating signal that represents the information to be transmitted (such as the desired power level for a motor), while the other input is a non-sinusoidal or Sawtooth wave that serves as a reference signal. The comparator compares these two signals and generates a PWM signal as its output waveform.
If the saw tooth wave is greater than the modulating signal, the comparator output will be in a "High" state. The magnitude of the difference between the two signals determines the comparator output, which defines the width of the pulse generated at the output. This process is repeated for each cycle of the saw tooth wave, resulting in a train of pulses with varying widths that encode the modulating signal.
Types of Pulse Width Modulation Technique :
There are three conventional types of pulse width modulation technique and they are named as follows:
Applications of Pulse Width Modulation (PWM) :
Advantages of PWM :
Practical use case of PWM in real life application :
PWM finds practical use in controlling the speed of DC motors by generating a PWM signal from a microcontroller to regulate the voltage applied to the motor. By adjusting the duty cycle of the PWM signal, the average voltage supplied to the motor can be varied, thus controlling the speed of the motor.
An excellent illustration of this is seen in electric scooters where the controller generates a PWM signal with a duty cycle corresponding to the desired speed, triggered by the user twisting the throttle. This technique offers precise speed control, cost-effectiveness, and durability since it reduces mechanical stress and overheating, ensuring a smooth and safe ride. Additionally, it eliminates the need for complex analog circuits and expensive components.
EmbeddedWala
EmbeddedWala Jun 14, 2023 0 21.1K
EmbeddedWala Apr 27, 2023 0 20.7K
EmbeddedWala Apr 26, 2023 0 18.3K
EmbeddedWala Aug 30, 2022 0 16.2K
EmbeddedWala Apr 27, 2023 0 16.2K
EmbeddedWala Jun 19, 2022 0 4.7K
This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies Find out more here