What is Pulse Width Modulation and How Does It Work?

Lance Harvie

TimelessBeginner

Pulse Width Modulation (PWM) is a technique used to control the average voltage supplied to a device or component by adjusting the width of a series of pulses. It works by rapidly turning a signal on and off at a specific frequency. The crucial element of PWM is the duty cycle, which represents the percentage of time the signal is “on” (high voltage) compared to the total time of one cycle.

Summary

This blog by Lance Harvie introduces Pulse Width Modulation (PWM), explaining how duty cycle and frequency control the effective voltage delivered to devices. It shows how PWM is generated on microcontrollers and embedded Linux, and discusses practical applications and trade-offs for LEDs, motors, and power management.

Key Takeaways

Calculate average voltage and power delivered from PWM using duty cycle and supply voltage
Configure microcontroller timers to produce stable hardware PWM and compare with software PWM approaches
Select PWM frequency and resolution appropriate for LEDs, motors, and analog reconstruction using low-pass filters
Design basic PWM-to-analog filters and understand trade-offs between ripple, response time, and component size
Mitigate motor-driver issues by applying dead-time, avoiding shoot-through, and choosing suitable driver/bridge components

Who Should Read This

Embedded and firmware engineers (early-career to mid-career) who need a practical grounding in PWM for microcontroller or embedded Linux projects involving LEDs, motors, sensors, or power control.

TimelessBeginner