Location:Training / Circuit Fundamentals / Analog / 60V buck-boost controller IC that can drive LEDs / 60V, 98% efficiency, four-switch synchronous buck-boost controller IC drives LEDs, regulates voltage and charges battery

LEDs are becoming more common and more powerful. 1A, 2A, 3A and higher current LED strings are widely used in vehicles, billboards, industrial lighting and many other applications, and they need to be driven accurately and efficiently by DC/DC converters. In many cases, a boost-buck topology is required due to voltage variations across the LED string and input supply. In this case, a four-switch synchronous buck-boost controller is the best solution due to its high efficiency and small circuit size.

Linear Technology's LT®3791 is a buck-boost controller IC designed to drive LED strings with input and output voltages up to 60V. It can drive more than 100W LEDs with an efficiency of more than 98%. It can smoothly switch from buck region to buck-boost region to boost region as input and output voltages change. LTC's high-end PWM dimming provides accurate and deep brightness control for LEDs. LED string short-circuit and open-circuit protection and diagnostic functions make this a powerful and very practical boost/buck LED driver.

The LT3791 can act as a constant current and constant voltage DC regulator, so it can also be used as an excellent high power buck-boost regulator with a voltage range up to 60V and short circuit protection. For special sealed lead-acid battery chargers, both constant current and constant voltage are required, and the LT3791 has a special 1/10 charger current sense function that can be used to convert a charged high-power SLA batteries switch from a "charging voltage" to a "floating voltage".