PWMSignals

PWMSignals refer to pulse-width modulated electrical signals used to regulate power delivery to a load. A PWM signal consists of a train of on/off pulses whose widths vary over time. The two defining parameters are the duty cycle, the fraction of each period that the signal remains high, and the switching frequency, how often the period repeats. The average voltage seen by a suitably filtered load is proportional to the duty cycle (for a fixed input voltage).

Generation and variants. PWM signals are produced by controllers in microcontrollers, dedicated PWM chips, or digital signal processors. They can be edge-aligned or center-aligned, and multiple channels are used for multi-phase systems. Common modulation schemes include conventional PWM, sinusoidal PWM, and space-vector PWM, the latter two often used in AC motor drives. In DC-DC converters, PWM controls the switching of power electronics to regulate the output voltage through filtering.

Applications. PWMSignals are widely used to control motor speed and torque, regulate power supplies, and enhance efficiency in switching amplifiers. Filtering the PWM waveform with inductors and capacitors yields a stable analog voltage or current, while direct switching can drive devices that tolerate high-frequency transitions. They are also used in audio amplification, where switching efficiency and precise control are advantageous.

Considerations. Higher switching frequencies reduce output ripple but increase switching losses and electromagnetic interference. Lower frequencies risk audible noise and larger filter components. Designers implement dead time to prevent shoot-through and manage timing jitter and synchronization. Characterizing PWM involves measuring the duty cycle, frequency, and the resulting average output, with Vout approximately equal to Vin times the duty cycle in a simple buck-like configuration.