The meaning of the term “high power LED” is rapidly evolving. Although a 350mA LED could easily earn the stamp of “high power” a few years ago, now, 5A to 40A LEDs and laser diodes are used in the DLP projector, surgical equipment, stage lighting, automotive lighting and other applications traditionally served by high intensity bulbs. To meet the light output requirements of these applications, high power LEDs are often used in series. The problem is that several series-connected LEDs require a high voltage LED driver circuit. LED driver design is further complicated by many applications that require fast LED current response to pulse width modulated (PWM) dimming signals.
The new LT®3763 is a 60V synchronous, step-down DC/DC controller designed to accurately regulate LED current at up to 20A with fast PWM dimming. It is a higher voltage version of its predecessors, the LT3743 and the LT3741. In addition to higher voltage, the LT3763 has 4 regulation loops that make it easy to design highly efficient, versatile and robust circuits.