Pulse width modulated signal can be generated by using a simple circuit as seen at Figure 1 below. This circuit consist of two main circuit blok, a triangle signal generator and a comparator. There is one input (voltage that need to be converted to PWM) and one output (PWM signal).

Figure 1. Pulse width modulated signal generator.

Figure 2 explains how pulse width modulated signal is built. When V input is greater than the amplitude of the triangle wave then comparator outputs is high, so do the opposite when V input is smaller then the amplitude of the triangle wave.

Figure 2. Pulse width modulated signal simulation.

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