The LT3492 is a triple output DC/DC converter designed to operate as a constant-current source and is ideal for driving LEDs. The LT3492 works in buck, boost or buck-boost mode. The LT3492 uses a fixed frequency, current mode architecture resulting in stable operation over a wide range of supply and output voltages. A frequency adjust pin allows the user to program switching frequency between 330kHz and 2.1MHz to optimize efficiency and external component size. The external PWM input provides 3000:1 LED dimming on each channel. Each of the three channels has a built-in gate driver to drive an external LED-disconnect P-channel MOSFET, allowing high dimming range. The output current range of each channel of the LT3492 is programmed with an external sense resistor. The CTRL pin is used to adjust the LED current either for analog dimming or over-temperature protection.Applications RGB Lighting Billboards and Large Displays Automotive and Avionic Lighting Constant-Current Sources

Demonstration circuit DC1666A is a synchronous four-switch buck-boost LED driver controller. It accepts an input voltage from 4.7V to 60V, and drives up to 25V of LEDs at 2A. DC1666A features both PWM and analog dimming of the LED string. It has an OPENLED flag that indicates when the LED string has been removed and it has a SHORTLED flag that indicates that the output has been shorted to GND. In both cases, the IC remains in control and well protected.

DC1947A: Demo Board for the LT3799-1 Offline Isolated Flyback LED Controller with Active PFC.

Demonstration circuit 2176A features the LT3909, a 2-string × 50mA, 2MHz step-up LED driver with ±1.8% current matching. The LT3909 precisely regulates two LED strings for equal current, supports LED dimming that reduces brightness down to a 1/40,000 ratio, protects against faults and also reports faults. The LT3909 consists of a step-up converter with a fixed 2MHz switching frequency and current sources for the LED strings. The maximum current in each LED string is 40mA. The ISET resistor can be changed to 20.0kΩ to program the string current to 50mA – see the data sheet for an application example with 50mA string current. Voltage feedback resistors optimize operation for LEDs that are 35V maximum.

The LTM8005 is a 38VIN, 38VOUT boost ?Module (powermicromodule) LED driver designed to regulate current orvoltage and is ideal for driving LEDs. The fixed frequencyand current mode architecture result in stable operationover a wide range of supply and output voltages. Spreadspectrum frequency modulation (SSFM) can be activatedfor improved electromagnetic compatibility (EMC) performance.The ground-referred voltage FB pin serves as theinput for several LED protection features, and also allows theconverter to operate as a constant voltage source. The PWMinput provides LED dimming ratios of up to 3000:1, and theCTRL inputs provide additional analog dimming capability.The low profile package enables utilization of unusedspace on the bottom of PC boards. The LTM8005 is packagedin thermally enhanced, compact over-molded BallGrid Array (BGA) package suitable for automated assemblyby standard surface mount equipment. The LTM8005is RoHS compliant.APPLICATIONS High Power LED, High Voltage LED Accurate Current-Limited Voltage Regulators

The LT8391 is a synchronous 4-switch buck-boost LED controller that regulates LED current from input voltage above, below, or equal to the output voltage. The proprietary peak-buck peak-boost current mode control scheme allows adjustable and synchronizable 150kHz to 650kHz fixed frequency operation, or internal ?15% triangle spread spectrum operation for low EMI. With 4V to 60V input, 0V to 60V output, and seamless low noise transitions between operation regions, the LT8391 is ideal for LED driver and battery charger applications in automotive, industrial, and battery-powered systems.The LT8391 provides both internal (up to 128:1) and external (up to 2000:1) LED current PWM dimming with a high-side PMOS switch. Two CTRL pins provide flexible 20:1 analog dimming with ?3% LED current accuracy at 100mV full scale. Fault protection is provided to detect an open or short LED condition, during which the LT8391 retries, latches off, or keeps running. Switching Frequency Max Output Power LT8391 Adjustable 150kHz - 650kHz 450W+ LT8391A 2MHz 50W+ APPLICATIONS Automotive Head Lamps/Running Lamps High Power LED Lighting

The LT3966 is an I2C programmable monolithic boost LED driver with four independent channels. Each channel provides a 60V current mode boost converter with an internal 1.6A DMOS power switch, as well as internal and external analog and PWM dimming features. I2C programmable features include a 13-bit (8192:1) digital PWM generator, 8-bit analog dimming DAC, and flexible fault reporting and handling.An onboard 8-bit ADC allows measurement of each channel?s output voltage and output current, as well as chip input voltage and two external measurements. In addition, independent shutdown and standby control of each channel provides flexible solutions for multitopology applications.The LT3966 is available in a thermally enhanced 6mm ? 6mm 40-Lead QFN package.ApplicationsBacklightingHeads Up Displays

Demonstration circuit 2788A is a boost LED driver featuring the LT®3950. This demonstration circuit powers a string of LEDs at 330mA. The step-up topology can be used to drive a string of up to 28V of LEDs as assembled. The maximum output voltage capability of the LT3950 is 60V. DC2788A runs from an input voltage range of 6V to 24V as built. It also runs at 2MHz and has the capability to turn on spread spectrum frequency modulation (SSFM) for a frequency range of 2.0MHz to 2.5MHz. Dimming control can be achieved with analog dimming or PWM dimming—either from an external or internally-generated clock source. DC2788A features undervoltage lockout (UVLO) set at 6.6V with a 1.0V hysteresis for turn-on. The UVLO voltage, LED current, output voltage range, switching frequency, brightness control, SSFM, and the topology can all be adjusted with simple modifications to the demonstration circuit. LT3950 is a monolithic 1.5A peak switch current, 60V LED driver. The guaranteed peak switch current rating of the IC is 1.5A and this is important to know when calculating maximum output current at a given LED voltage and input voltage for a boost converter. The LT3950 features SSFM and a well-controlled SW node for low emissions. A frequency range of 200kHz to 2MHz and a high-side PWMTG PWM-dimming MOSFET makes this a very versatile IC for many applications. It can be used for boost, buck-boost mode and buck mode LED driver applications. The PWMTG MOSFET not only provides high PWM dimming ratio capability, but it also serves as a short-circuit protection device. The FAULT flag indicates when there is either a short-circuit or open-LED fault at the output. The demo circuit is designed to be easily reconfigured to suit other applications, including the example schematics in the data sheet. Consult technical support for assistance. High voltage operation, 3V input voltage operation, multiple topologies, small-and-compact size, fault protection, low EMI, and multiple brightness control options make the LT3950 flexible and powerful for compact, noise-sensitive LED driver solutions. The LT3950JMSE featured on this demo circuit is available in a thermally enhanced 16-lead plastic MSOP package. The LT3950 data sheet must be read in conjunction with this demo manual to properly use or modify demo circuit DC2788A.

Laser Drivers

110MHz ANALOG INTFCE FOR SGA FPD