The LTC3202 is a low noise, constant frequency charge pump DC/DC converter that uses fractional conversion to increase efficiency in white LED applications. The part can be used to produce a regulated voltage or current of up to 125mA from a 2.7V to 4.5V input. Low external parts count (two flying capacitors and two small bypass capacitors at VIN and VOUT) make the LTC3202 ideally suited for small, battery-powered applications.An internal 2-bit DAC allows LED current to be adjusted for LED brightness control. The LTC3202 also has thermal shutdown protection and can survive a continuous short-circuit from VOUT to GND. Built-in soft-start circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small external capacitors. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1?A.The LTC3202 is available in the 10-pin MSOP and 3mm x 3mm DFN packages.Applications White LED Backlighting Programmable Boost Current Source?

DC871A-A: Demo Board for the LTC3215 700mA Low Noise High Current LED Charge Pump.

DC902A-B: Demo Board for the LTC3214 500mA Camera LED Charge Pump.

The LT3478/LT3478-1 are 4.5A step-up DC/DC converters designed to drive LEDs with a constant current over a wide programmable range. Series connection of the LEDs provides identical LED currents for uniform brightness without the need for ballast resistors and expensive factory calibration.The LT3478-1 reduces external component count and cost by integrating the LED current sense resistor. The LT3478 uses an external sense resistor to extend the maximum programmable LED current beyond 1A and also to achieve greater accuracy when programming low LED currents. Operating frequency can be set with an external resistor from 200kHz up to 2.25MHz. Unique circuitry allows a PWM dimming range up to 3000:1 while maintaining constant LED color. The LT3478/LT3478-1 are ideal for high power LED driver applications such as automotive TFT LCD backlights, courtesy lighting and heads-up displays. One of two CTRL pins can be used to program maximum LED current. The other CTRL pin can be used to program a reduction in maximum LED current vs temperature to maximize LED usage and improve reliability.Additional features include inrush current protection, programmable open LED protection and programmable soft-start. Each part is available in a 16-pin thermally enhanced TSSOP Package.Applications High Power LED Driver Automotive Lighting

Demonstration circuit 976 is a Quadruple High Power LED Driver in Buck Mode featuring the LT3476EUHF. The LT3476 is a quad output, multitopology DC/DC converter designed to operate as a current source for driving high current LEDs. Each of the four regulators on the demo circuit is independently operated. The VIN power supply for the IC ranges from 2.8V to 16V. The PVIN power supply for the buck regulators ranges up to 33V. On the demo circuit, the default current for each output channel is 350mA but it can be adjusted up to 1.05A via resistor dividers at the VADJ pins. The output current should not exceed the rated current of the LEDs used. If 1W LEDs, such as the Lumileds Luxeon LEDs, are used, 350mA current is the maximum. 1A output current is reserved for 3W LEDs, such as Luxeon III. The input voltage is limited by the CAP pin overvoltage protection threshold. As a result, each channel of the demo circuit can drive up to 27V total LED voltage.

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 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

DC805A: Demo Board for the LTC3216 1A Low Noise High Current LED Charge Pump with Independent Torch/Flash Current Control.