PWM Digital Modulation: What is it and where is it applied?

In the electronics and LED lighting sector, it is very common to hear about PWM (Pulse Width Modulation). Pulse width modulation is a digital control technique created to replace the regulation of voltage and current through the use of rheostats or potentiometers.

A PWM system is able to modify the duty cycle of an electrical device and maintain it as defined by the user. The duty cycle of a component is the ratio between the time in which the signal remains on compared to the total operating time.

PWM technology makes it easier to regulate electrical systems of various types and sizes, starting from LED driver power supplies to motors, valves and hydraulic pumps.

Let's define what PWM modulation is and what are the typical applications of use.

PWM modulation, an acronym for Pulse Width Modulation, is a signal capable of regulating the output voltage from a direct current source and, at the same time, significantly limiting the power dissipated by the electrical system.

The operation of a PWM circuit depends on a switch placed between the source and the load that performs a high-speed ON/OFF action, generating an average voltage value compared to the full capacity of the system. The result is the possibility of varying the output voltage of a power supply or modifying the light intensity of an LED.

The purpose of PWM regulation is to make a device operate at a lower value than its standard power supply, since it is not possible to start an electrical component without respecting the minimum characteristics provided for start-up; here is an in-depth analysis on the management of start-up current peaks.

The advantage of PWM technology is the drastic reduction of dissipated power, with greater system efficiency. The transition between the two states of on and off (which do not involve any loss of power) occurs in a much shorter time than the standard, and for this reason the dissipated power is very low in relation to the power supplied.

Pulse width modulation (PWM) is commonly used in electrical devices and communication protocols. Used to change the voltage (and therefore the power) of an electrical load, PWM technology is frequently found in:

• Switching power supplies: PWM modulation is used to regulate power supplies without power losses, thus increasing the level of efficiency. In switching power supplies, the PWM signal is regulated as a function of the output voltage, inducing a stabilizing feedback as the input current varies. Simply put, a PWM power supply inserted in a system that requires less energy will operate with a lower amount of current and already regulated.

• LED drivers: PWM modulation is able to vary the intensity of light sources such as incandescent bulbs or LED devices at will. A PWM circuit inserted into light controllers effectively meets the most precise dimming requirements of the light that manage high dimming ratios at high frequencies. Furthermore, using a PWM LED driver helps avoid flickering and stroboscopic effects.

With particular interest in the LED Lighting sector, Digimax solutions with PWM modulators find application in advanced and innovative lighting systems, allowing full control of light with modern and cutting-edge features such as:

• PWM Mean Well intelligent LED drivers: ideal for managing light in wireless smart lighting applications, with Bluetooth technology for interconnection with other devices and Casambi protocol for complete control of the system.

• PWM-DA2 Mean Well digital LED drivers with DALI2 technology for light regulation: designed in compliance with international safety certifications, IEC 62386 and EN 61374 regulations for emergency lighting.

• KNX Mean Well LED drivers with PWM modulation: together with KNX technology, the output frequency can be changed by the user while maintaining the color temperature and light homogeneity in the management of all LED devices.

Discover Digimax solutions dedicated to the professional power supply and lighting market, together with our dedicated consultancy service during the design phase.