One of the most popular methods for controlling semiconductor devices is pulse width modulation, or PWM. The PWM technique uses a variety of digital hardware to generate analog signals. The generated signals have a square waveform that represents the impulse. As a result, it is time-dependent and as a result, it can be high or low at any given moment. PWM reduced the electrical signal’s gain in power range. By splitting up the PWM signals into separate components, it can be carried out. The majority of communication systems use this method.

What is Pulse Width Modulation?

What is pwm technique, also known as pulse width modulation technique? It is a type of modulation technique that is used to modulate signals. By converting the electrical signal into discrete parts, it is possible to reduce the average power that is communicated by the electrical signal. Instead of a continuously fluctuating (analog) signal, energy is distributed through a series of pulses in the PWM technique.

How is a PWM Signal Generated

A monostable multivibrator is capable of producing a pwm signal. When an external trigger is applied, a monostable multivibrator produces a single output pulse and has only one stable state. An operational amplifier comparator can be used to build a monostable multivibrator circuit. The non-sinusoidal waveforms structure one portion of the input to the comparator while the modulating signal structures the other portion of the data. When two signals are compared, the comparator generates a PWM signal as the output waveform. The output is in a “High” state if the sawtooth signal or non-sinusoidal signal is greater than the modulating signal. The size’s value determines the comparator yield, which defines the pulse’s width at the output.

PMW Signal

Comparator generating pulse width modulation.

Duty Cycle of PWM

We call this being “on time” when the signal is strong. We use the concept of duty cycle to illustrate how much is “on time”. Duty cycle estimates are expressed as percentages. The percentage of duty cycle clearly shows how much of a given period of time a digital signal is on. The frequency of the waveform is opposite to this period.

We agree that a digital signal has a duty cycle of 50% and appears like an ideal square wave if, on the off chance, it spends half of the time on and the other half off. The digital signal spends more time in the high state than the low state on the off chance that the percentage is higher than 50%, and vice versa on the off chance that the duty cycle is lower than 50%. The following diagram illustrates these three scenarios:

Duty Cycle

Ignition voltage variation with duty cycle.

Frequency

To control a specific servo, a frequency or period must be specified. A servo engine regularly anticipates an update every 20 ms with a pulse of between 1 ms and 2 ms. This contrasts with a 5%–10% obligation pattern at 50 Hz. The servo engine will be at 90 degrees, 0 degrees, and 180 degrees at present, assuming the pulse is at 1.5 ms. In summary, we can obtain a complete range of motion by refreshing the servo with a value between 1 ms and 2 ms.

Additionally, PWM is currently being used in a system that uses clear communication, and its duty cycle is being used to transmit data over communication channels. PWM is a method for converting high-frequency pulses into low-frequency output signals.

Frequency=1 / Time period

Frequency of PWM

Applications

PWM is used in many applications as given below.

• Modulation techniques are frequently used to control appliances like DC motors and LEDs.
• Modulation in electronic devices refers to the application of a regulating or fluctuating impact on something. As in the human voice, we also refer to it as variation in the pitch, strength, or tone of a frequency.
• By altering the duty cycle, an LED’s brightness can be somewhat controlled. With an RGB (red, green, blue) LED, you can adjust how much of each of the three colors you require in the mixture of variety by subtracting them in various amounts.
• One of the key methods for reducing a solar panel’s output so that it can be used by a battery is to pair PWM with maximum power point tracking (MPPT).
• The PC’s CPU fan is controlled by the PWM procedure, which effectively dissipates heat.