March 13, 2012 – Linear Technology Korea (CEO Hong Sa-kwak) announced the development of a synchronous buck-boost DC/DC LED driver and voltage controller (product name: LT3791) capable of delivering 100W LED output. The product features an input voltage range of 4.7V to 60V, making it ideal for various applications including automotive, industrial, and architectural lighting. The output voltage can also be set in the range of 0V to 60V, enabling the LT3791 to drive various LEDs on a single string. The internal 4-switch buck-boost controller operates with input voltages higher than, lower than, or equal to the output voltage, making it ideal for automotive applications where input voltage fluctuates significantly during stop/start, cold cranking, and load dump events. The seamless transitions between buck, pass-through, and boost operation modes ensure uniform output even when supply voltage varies significantly. The LT3791 features a unique design employing three control loops to monitor input current, LED current, and output voltage, providing optimal performance and reliability.
The LT3791 utilizes four external switching MOSFETs and delivers continuous LED power from 5W to 100W with maximum efficiency of 98.5%. LED current accuracy of ±6% ensures consistent illumination, and output voltage accuracy of ±2% allows this converter to operate as a constant voltage source. The LT3791 can apply analog or PWM dimming depending on the application. Additionally, the switching frequency can be programmed in the range of 200kHz to 700kHz or synchronized with an external clock. Other features include output shutdown, input and output current monitoring, open and short LED detection, and integrated fault protection functionality.
The LT3791EFE is available in a 38-pin TSSOP package with enhanced thermal performance, priced from $4.75 per unit based on quantities of 1,000. The temperature-extended version or I-grade LT3791IFE is also available, priced from $5.25 per unit based on quantities of 1,000. The high-temperature version or H-grade LT3791HFE starts from $5.50 per unit based on quantities of 1,000. The high-reliability MP-grade version LT3791MPFE is also currently available, priced at $14.75 per unit based on quantities of 1,000. All versions are available for immediate purchase. For detailed product information, refer to www.linear.com/product/LT3791.
Photo Description: 60V input/output synchronous buck-boost LED driver capable of over 100W LED output

Product Features: LT3791

• 4-switch single inductor architecture enabling input voltage higher than, lower than, or equal to output voltage
• Wide input voltage range: 4.7V to 60V
• Wide output voltage range: 0V to 60V (55V LED)
• ±2% output voltage accuracy
• Synchronous switching: 98.5% or higher efficiency
• ±6% LED current accuracy: 0V ≤ VOUT < 60V
• Output voltage isolated from input voltage during shutdown
• Precise rail-to-rail LED current sensing via monitor output
• Input current sensing via monitor output
• PWM & analog dimming
• Programmable hysteresis and UVLO for shutdown
• Over 100W possible per IC
• 38-pin TSSOP with exposed pad