PWM is a control method applicable to many power supply topologies. Power supplies of any topology have a very wide range of uses and can be described as ubiquitous; and PWM has a wide range of applications.
PWM is an acronym for Pulse Width Modulation. In switching power supplies, PWM is used to regulate outputs such as output voltage and suppress changes in system input voltage. This system concept describes a switching power supply. The input and output can be DC, sinusoidal (AC), or even some other periodic waveform.

PWM applications include welding, home appliances, motor drives, personal electronics, inverters, electric vehicles, uninterruptible power supplies, solar power, audio amplifiers, and automotive heaters. In general, simple general-purpose PWM controllers are recommended where switching power supplies are used and complex advanced topologies are not required.
Using a sensible PWM controller in many applications can help reduce development time, and can also increase confidence in power supply design with a range of robust designs. A final advantage of PWM is that it can be used in multiple designs, allowing procurement teams to source components in high volumes. The production process of general-purpose PWM controllers has evolved from bipolar technology to today's Bi-CMOS technology, and its key design parameters have been greatly improved.