Demonstration circuit 1055 is a 250mA Universal Nine Channel Multimode (1x, 1.5x, 2x) Charge Pump LED Driver with two RGB displays and three white LEDs featuring the LTC3219. The LTC3219 is a low noise charge pump designed to drive nine universal LED current sources. The input voltage range is 2.9V to 5.5V. Each channel provides 28mA of LED current. The LTC3219 requires only five small ceramic capacitors to form a complete LED power supply and current controller. The maximum display currents are set with an internal precision current reference. On/Off blinking, gradation, and intensity are achieved via an I2C serial interface. There are 64 dimming states available for the universal LEDs. The DC590 controller board is required for proper operation.

Demo circuit DC1274A features the LTM8040 36V, 1A step-down constant current μModule® LED driver. The demonstration circuit is designed to drive a single LED or string of LEDs at up to 1A from a wide input voltage range of 4V to 36V. The maximum LED string voltage is 13V and the minimum voltage varies depending upon the BIAS pin supply arrangement.

Demonstration Circuit 1279 is a full-featured, multitopology LED driver with 1.5A switch current featuring the LT3518. The board is optimized to drive a 330mA LED string with a total LED voltage between the input voltage and 40V in a boost topology. The input voltage range (VIN) is 3V to 30V, and the supply pin that powers the switcher (PVIN) has an input voltage range of 3V to 40V.

Demonstration circuit DC2342A is a 60V synchronous boost LED controller featuring the LT®3762. It drives a single string of LEDs at 2A up to 32V when VIN is between 7V and 28V. It runs down to 4VIN with reduced ILED and can withstand VIN transients as high as 30V. DC2342A runs at approximately 300kHz switching frequency. Spread spectrum frequency modulation (SSFM) can be turned on with a simple jumper, reducing EMI. DC2342A is designed for high power step-up LED controller applications that require excellent efficiency across the VIN range. This demonstration circuit is protected against both open and short LED conditions, each having its own flag. The LT3762 has an input range from 2.5V to 42V. It has an adjustable switching frequency between 100kHz and 1MHz. Enabling SSFM spreads the switching frequency from fSW down to fSW – 30% for reduced EMI. SSFM speed is set by placing a capacitor from the SSFM pin of the LT3762 to ground, and can be disabled by shorting this pin to GND. DC2342A has a simple jumper option to enable/disable spread spectrum frequency modulation. The LT3762 can be PWM dimmed with an external PWM signal, as well as an internally generated PWM signal. A capacitor from PWM to GND of the LT3762 sets the PWM frequency, while the PWM duty cycle is determined by the voltage on the DIM terminal. Between 0V and 3V, VDIM gives between 0.4% and 97% PWM duty cycle. DC2342A has a jumper that can be set to switch between internally generated PWM signal, externally generated PWM signal, and no PWM signal (100% on). When run with both PWM dimming and spread spectrum enabled, the spread spectrum aligns itself with the PWM signal for flicker free operation. DC2342A can also be analog dimmed by placing a voltage source at either of its two CTRL turrets. Small ceramic input and output capacitors are used to save space and cost. The open LED overvoltage protection uses the IC’s constant voltage regulation loop to regulate the output to approximately 35.5V if the LED string is opened, although it may reach almost 40V peak during the transient caused by an open circuit. There is a protection diode from LED+ to GND to prevent negative ringing during a short-circuit. Undervoltage lockout can be adjusted on the circuit with a few simple resistor choices. Further modifications can be made to DC2342A to reconfigure the circuit from a boost topology to operate as a buck-mode or buck-boost mode LED driver. Please consult the factory for details. The LT3762 data sheet gives a complete description of the part, operation and applications information. The data sheet must be read in conjunction with this Demo Manual for demonstration circuit DC2342A. The LT3762EUFD is assembled in a 28-lead plastic 4mm × 5mm QFN package with a thermally enhanced ground pad. Proper board layout is essential for maximum thermal performance. See the data sheet section Layout Considerations.

The LT3952A is a current mode step-up DC/DC converter with an internal, 60V, 80m? DMOS power switch. The LT3952A is specifically designed to drive high power LEDs in multiple configurations. It combines input and output current regulation loops with output voltage regulation to operate as a flexible current/voltage source.Programmable switching frequency with optional spread-spectrum modulation provides EMI reduction, while still allowing optimization of the external components for efficiency or component size. The LED current is programmable with an external sense resistor, and can be adjusted from zero to full scale with a voltage at the CTRL pin. The external PWM input provides LED ON/OFF control and 4000:1 dimming ratio, and an internal PWM generator delivers the efficiency of PWM dimming to standalone or I/O limited applications. The LT3952A is available in the thermally enhanced 28-lead TSSOP package.Applications Display Backlighting Automotive and Avionic Lighting Accurate Current-Limited Voltage Regulators

The LT3491 is a fixed frequency step-up DC/DC converter specifically designed to drive up to six white LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The device features a unique high side LED current sense that enables the part to function as a ?one wire current source;? one side of the LED string can be returned to ground anywhere, allowing a simpler one wire LED connection. Traditional LED drivers use a grounded resistor to sense LED current, requiring a 2-wire connection to the LED string.The 2.3MHz switching frequency allows the use of tiny inductors and capacitors. A single pin performs both shutdown and accurate LED dimming control. Few external components are needed: open-LED protection and the Schottky diode are all contained inside the tiny SC70 package. With such a high level of integration, the LT3491 provides a high efficiency LED driver solution in the smallest of spaces.Applications Cellular Phones PDAs, Handheld Computers Digital Cameras MP3 Players GPS Receivers

Demonstration circuit DC915 features the LT3466-1 high efficiency boost white LED driver and a step-up converter. There is one LED driver output for 6 or 8 WLEDs and a separate DC/DC converter that generates outputs for the LCD bias. VO1 drives 8 LEDs in series with 15mA LED current and VO2/VO3 can delivery ±15V at 10mA current. If the charge-pump circuitry which generates VO3 is removed (C4, C5 and D1), VO2 can deliver over 35mA of current. The input voltage range is 3V to 14V, but can go as low as 2.7V with slightly reduced output current.

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

LED Lighting Drivers 1.0A LED Flash Driver

3.3 V Dual-Loop 50 Mbps to 3.3 Gbps Laser Diode Driver