LED Drivers
Products (3)
L99LD21 - Automotive High Power LED Driver | STMicroelectronics
The L99LD21 is an automotive-grade, high-power LED driver from STMicroelectronics, specifically designed to control two independent high-brightness LED strings for automotive front lighting applications. It integrates a boost controller with a high-side current source, enabling efficient and precise current regulation for LED strings with forward currents up to 1.5 A (average) and forward voltages up to 50 V. The device operates from a wide battery voltage range of 5.5 V to 24 V and is load dump protected, making it suitable for both 12 V and 24 V automotive electrical systems. An LED driver is a power management IC that regulates the current flowing through one or more LEDs to ensure consistent brightness and protect the LEDs from current-induced damage. In automotive lighting, LED drivers are essential for headlamps, daytime running lights, and interior lighting, where they convert the vehicle's battery voltage into a controlled current source. The L99LD21 belongs to the family of automotive LED drivers, which are part of the broader power management IC category, and are designed to meet stringent automotive reliability standards such as AEC-Q100. Key features of the L99LD21 include a wide input voltage range, high output current capability, and integrated protection features such as over-temperature and over-voltage protection. The device supports PWM dimming for brightness control and includes a fault diagnostic output for system monitoring. Its high efficiency reduces power dissipation, which is critical in thermally constrained automotive environments. The device is AEC-Q100 qualified, ensuring reliability for automotive applications. The L99LD21 uses a boost converter topology to step up the battery voltage to the level required by the LED string, while the integrated high-side current source regulates the LED current with high accuracy. This architecture minimizes external component count and simplifies PCB layout. The device is available in a compact QFN40L 6x6 package with wettable flanks and exposed pad, suitable for space-constrained automotive modules. It also features ST SPI communication v4.1, a timeout watchdog, and a limp home function for enhanced safety. Typical applications include automotive headlamps, daytime running lights, fog lamps, and interior ambient lighting. The device's robust design and automotive qualification make it suitable for use in harsh environments with wide temperature variations and electrical transients. The L99LD21 is also available as an evaluation board (L99LD21-ADIS) for development and testing. When designing with the L99LD21, it is important to ensure proper thermal management and to select external components that meet the device's specifications. The PWM dimming input allows for flexible brightness control, and the fault output can be used to implement diagnostic functions in the vehicle's lighting control unit. The device's low standby current helps reduce power consumption when the lighting system is not in use.
LT3791EFE#PBF - 60V 4-Switch Sync Buck-Boost LED Driver | ADI
The LT3791EFE#PBF from Analog Devices is a synchronous 4-switch buck-boost LED driver controller capable of regulating LED current up to 52V with input voltages above, below, or equal to the output voltage. Housed in a 38-pin TSSOP-EP package, this controller supports a wide input voltage range and delivers high efficiency up to 98.5%. A buck-boost LED driver controller is a power management IC that regulates current through an LED string by controlling four external MOSFETs in a single-inductor topology. It can step up or step down the input voltage to maintain a constant LED current, making it essential for applications where the supply voltage varies around the LED forward voltage. This controller sits within the hierarchy of LED drivers, which are part of power management integrated circuits used in lighting systems. Key features include a 4-switch single-inductor architecture that allows VIN above, below, or equal to VOUT, synchronous switching for efficiency up to 98.5%, a wide input voltage range, and 2% output voltage accuracy. The controller supports both analog and PWM dimming, with a frequency adjustable or synchronizable from 200kHz to 700kHz. It also provides open LED and short LED protection, along with a precision current sense amplifier. The LT3791EFE#PBF uses a constant-frequency, current-mode architecture with forced-continuous operation, ensuring stable operation across all conditions. The 4-switch topology eliminates the need for a separate boost and buck stage, reducing component count and board space. The controller can regulate LED current with ±2% accuracy, and its wide input range makes it suitable for automotive, industrial, and general lighting applications. Typical applications include automotive headlamps, industrial lighting, and high-power LED drivers. The device is ideal for battery-powered systems where input voltage varies, such as in vehicles or portable equipment. Its ability to operate with input voltages above or below the LED string voltage makes it versatile for various LED configurations. When designing with this controller, ensure proper PCB layout for the high-current switching paths and adequate thermal management for the external MOSFETs. The frequency synchronization pin allows multiple controllers to operate at the same frequency, reducing EMI in multi-channel designs.
LT3791EFE#TRPBF - 60V 4-Switch Sync Buck-Boost LED Driver | ADI
The LT3791EFE#TRPBF from Analog Devices is a synchronous 4-switch buck-boost LED driver controller designed to regulate LED current up to 52V with input voltages above, below, or equal to the output voltage. Housed in a 38-pin TSSOP-EP package, this controller supports constant-frequency, forced-continuous current mode operation, enabling efficient and accurate LED current regulation across a wide input range. A buck-boost LED driver controller is a specialized power management IC that combines step-down (buck) and step-up (boost) topologies to maintain a regulated output current regardless of whether the input voltage is higher or lower than the LED string voltage. This makes it ideal for automotive, industrial, and general lighting applications where input voltage variations are common. The LT3791 belongs to the family of switching regulators, specifically DC-DC controllers, which are essential in power management systems for converting and regulating electrical power efficiently. Key features include a wide 4.7V to 60V input voltage range, adjustable switching frequency from 200kHz to 700kHz, and the ability to synchronize to an external clock. The controller provides analog and PWM dimming, with PWM dimming capable of achieving high contrast ratios. Its 4-switch architecture allows seamless transitions between buck, boost, and buck-boost modes, ensuring stable operation across the entire input range. The device also includes features such as open LED protection, short-circuit protection, and a precision current sense amplifier. Technically, the LT3791 uses a current mode control architecture with a 4-switch synchronous topology, which improves efficiency by eliminating the need for external Schottky diodes. The controller can drive external N-channel MOSFETs, allowing designers to scale the solution to high-power applications. The forced-continuous current mode ensures predictable operation and simplifies EMI filtering. The device operates over a -40°C to 125°C junction temperature range, making it suitable for harsh environments. Typical applications include automotive LED lighting (headlights, daytime running lights), industrial lighting, and general-purpose constant-current LED drivers. Its wide input range and high output voltage capability make it particularly well-suited for LED strings in series, where the total forward voltage can be significant. When designing with the LT3791, careful attention must be paid to the switching node layout and the selection of external components, such as inductors and MOSFETs, to ensure stable operation and meet EMI requirements. The datasheet provides detailed application circuits and component selection guidelines.