The automotive industry makes extensive use of light-emitting diodes (LEDs) in high-beam headlights, brake and position lights, and side and rear direction lights. In an LED driver design, the brightness intensity of the various illuminating devices is not equal; rather, it depends on their specific function.
Needless to say, then, that LEDs operate at different brightness levels—for example, at full brightness for braking and from 10% to 25% for the rear lights. LED dimming circuits are used to differentiate the brightness level through a pulse-width-modulation (PWM) driving technique, which modulates the width of the current pulses applied to the LEDs. LED driver solutions integrate a PWM system to control the brightness by providing a ramp generator, thus simplifying the driver design.
PWM has been adopted as the preferred dimming technique for high-quality LED lighting. An essential aspect of the lighting control system is the power management provided by integrated-circuit (IC) drivers in several configurations, such as buck and buck-boost topologies. The ease of controlling LEDs makes them an intelligent lighting system.