DC/DC LED Drivers Delivering Power Over 100W

　　Linear Technology Corporation introduces the LT3791, a synchronous buck-boost DC/DC LED driver and voltage controller that can deliver over 100W of LED power. Its 4.7V to 60V input voltage range makes the device ideal for a wide variety of applications, including automotive, industrial and architectural lighting. Similarly, its output voltage can be set from 0V to 60V, allowing the LT3791 to drive a single string of LEDs in a variety of configurations. The 4-switch buck-boost controller inside the LT3791 operates from input voltages above, below or equal to the output voltage, making it ideal for applications such as automotive, where the input voltage can vary widely during stop/start, cold crank and load dump conditions. Transitions between buck, pass-through and boost operating modes are seamless, so the device provides a well-regulated output even with wide variations in supply voltage. The LT3791's unique design uses three control loops to monitor input current, LED current and output voltage to provide optimal performance and reliability.

        3791 can provide more than 100W of LED power

　　The LT3791 uses four external switching MOSFETs to continuously deliver LED power from 5W to over 100W with efficiencies up to 98.5%. The LED current accuracy is ±6%, ensuring constant lighting, while the output voltage accuracy of ±2% enables the converter to operate as a constant voltage source. Analog or PWM dimming can be used as required by the application. In addition, the switching frequency can be set from 200kHz to 700kHz or synchronized to an external clock.

　　The LT3791 has a ground reference voltage FB pin that serves as the input for multiple LED protection functions and also enables the converter to function as a constant voltage source. It operates in forced continuous mode, making it ideal for systems with stringent EMI requirements. The device provides fault protection to withstand and promptly report LED open or short circuit conditions. A timer allows the LT3791 to perform "continue to run", "latch off" or "restart" operations in the event of a fault.