DC484A: Demo Board for the LT1937 White LED Step-Up Converter in SC70 and ThinSOT.

The ADM8845 uses charge pump technology to provide thepower required to drive up to six LEDs. The LEDs are used forbacklighting a color LCD display, having regulated constant current for uniform brightness intensity. The main display canhave up to four LEDs, and the sub display can have one or two LEDs. The digital CTRL1 and CTRL2 input control pins controlthe shutdown operation and the brightness of the main and subdisplays.To maximize power efficiency, the charge pump can operate ina 1?, 1.5?, or 2? mode. The charge pump automaticallyswitches between 1?/1.5?/2? modes, based on the input voltage,to maintain sufficient drive for the LED anodes at the highestpower efficiency. Improved brightness matching of the LEDs is achieved by afeedback pin to sense individual LED current with a maximum matching accuracy of 1%.Applications Cellular phones with main and sub displays White LED backlighting Camera flash/strobes and movie lights Micro TFT color displays DSC PDAs

The LTC3207/LTC3207-1 are highly integrated multi-display LED drivers. The device contains a high-efficiency, low-noise charge pump to provide power to 12 universal LED current sources and one camera LED current source. The LTC3207/LTC3207-1 require only five small ceramic capacitors to form a complete LED power supply and current controller. In addition there are two I2C addresses available.The display currents are set by an internal precision current reference. Independent dimming, On/Off, blinking and gradation control for all universal current sources is achieved via the I2C serial interface. 6-bit linear DACs are available for adjusting brightness levels for each universal LED current source. The CAM current source has a 4-bit linear DAC to adjust brightness.The LTC3207/LTC3207-1 charge pumps optimize efficiency based on the voltage across the LED current sources. The device powers-up in 1x mode and will automatically switch to boost mode whenever any enabled LED current source begins to enter dropout. The first dropout switches the IC into 1.5x mode and a subsequent dropout switches the LTC3207/LTC3207-1 into 2x mode. The device resets to 1x mode whenever a data register is updated via the ?I2C?port.Applications Video Phones with QVGA+ Displays

Evaluation board EVAL-LT8356-1-AZ is a high voltage LED controller featuring the LT8356-1. It is assembled as a buck-boost mode LED driver but can be altered to a boost LED driver by adjusting the FB network and LED-connection. EVAL-LT8356-1-AZ drives a single string of LEDs up to 36V at 1A when the input is between 8V and 36V. It has an undervoltage lockout (UVLO) set at 6.5V falling and 7.5V rising. The evaluation board features PWM dimming, analog dimming, shutdown, open LED and short LED fault protection and reporting. EVAL-LT8356-1-AZ runs at 250kHz switching frequency and features spread spectrum frequency modulation (SSFM) modulating its switching frequency from 250kHz to 310kHz to reduce EMI emissions. Small ceramic input and output capacitors are used to save space and cost. A high voltage 100V external power switch and 100V catch diode are used for up to 36W buck-boost mode output as assembled. The open LED overvoltage protection (OVP) uses the IC’s constant voltage regulation loop to limit the LED+ to LED– voltage to approximately 41V if the LED string is opened. The VOUT, if referenced to GND, will jump to VIN + 41V if the LED string is opened. The input and output filters on EVAL-LT8356-1-AZ help further reduce its EMI. These filters consist of a small ferrite bead or inductor and high frequency ceramic capacitors. A small resistor on the gate pin of the power MOSFET is used to reduce high frequency EMI. These filters, combined with proper board layout and SSFM, are very effective in reducing EMI to comply with CISPR25 class 5 limits. Please follow the recommended layout and the four-layer PCB thickness of EVAL-LT8356-1-AZ. For best efficiency and PWM dimming performance, the EMI filters can be removed. The LT8356-1’s integrated PWMTG high-side PMOS driver assists with PWM dimming of the connected LEDs. The LED string can be PWM-dimmed for accurate brightness control with an externally generated PWM signal for highest achievable dimming ratio. It can also utilize LT8356-1’s internally generated PWM feature for up to 128:1 exponential dimming. When running PWM dimming, the SSFM aligns itself with the PWM signal for flicker-free operation of the LED string. This applies to both internal and external PWM dimming. The LT8356-1 uses CTRL and IADJ pins for two-pin analog dimming. The input undervoltage lockout (UVLO), LED current, output overvoltage protection (OVP), and switching frequency, can all be easy adjusted with simple resistor changes to EVAL-LT8356-1-AZ. Modifications can be made to convert the board from buck-boost mode LED driver to boost and buck mode LED Driver, and maintain low EMI, PWM dimming and fault diagnostic features. Buck mode and boost LED Driver schematics are provided in the data sheet. Please consult the data sheet or the applications team regarding how to customize EVAL-LT8356-1-AZ. The LT8356-1 data sheet gives a complete description of the part, operation, and applications information. The data sheet must be read in conjunction with the demo manual for evaluation board EVAL-LT8356-1-AZ. The LT8356IUDCM-1 is assembled in a 20-lead side solderable plastic QFN package with a thermally enhanced exposed ground pad. Proper board layout is essential for maximum performance. See the data sheet section “Designing the Printed Circuit Board”.

6-String 30mA LED Driver with 1.5% Current Matching Features: True Color PWM™ Dimming Delivers Up to 3000:1 Dimming Ratio Drives Six Strings of LEDs at Up to 30mA ±1.5% Accurate LED Current Matching Wide Input Voltage Range: 3.2V to 30V Output Voltage Up to 44V Regulates Current Even When VIN > VOUT Disconnects LEDs in Shutdown Programmable Open LED Protection (Regulated) OPENLED Alert Pin Programmable LED Current Derating Adjustable Frequency: 200kHz to 2.5MHz Synchronizable to an External Clock Parallel Channels for Higher Current per LED String Thermally Enhanced 4mm × 4mm QFN and 24-Lead TSSOP Packages

The ADM8845 uses charge pump technology to provide thepower required to drive up to six LEDs. The LEDs are used forbacklighting a color LCD display, having regulated constant current for uniform brightness intensity. The main display canhave up to four LEDs, and the sub display can have one or two LEDs. The digital CTRL1 and CTRL2 input control pins controlthe shutdown operation and the brightness of the main and subdisplays.To maximize power efficiency, the charge pump can operate ina 1×, 1.5×, or 2× mode. The charge pump automaticallyswitches between 1×/1.5×/2× modes, based on the input voltage,to maintain sufficient drive for the LED anodes at the highestpower efficiency. Improved brightness matching of the LEDs is achieved by afeedback pin to sense individual LED current with a maximum matching accuracy of 1%.Applications Cellular phones with main and sub displays White LED backlighting Camera flash/strobes and movie lights Micro TFT color displays DSC PDAs

LED Lighting Development Tools LTM8042EV-1 Demo Board - 32V, 350mA Mod

The LTC3441 is a high efficiency, fixed frequency, buck-boost DC/DC converter that operates efficiently from input voltages above, below or equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single lithium ion or multicell applications where the output voltage is within the battery voltage range.The device includes two 0.10? N-channel MOSFET switches and two 0.11? P-channel switches. External Schottky diodes are optional, and can be used for a moderate efficiency improvement. The operating frequency is internally set to 1MHz and can be synchronized up to 1.7MHz. Quiescent current is only 25?A in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin is driven low or with a clock, then fixed frequency switching is enabled.Other features include a 1?A shutdown, soft-start control, thermal shutdown and current limit. The LTC3441 is available in a thermally enhanced 12-lead (4mm ? 3mm) DFN package.Applications Handheld Computers Handheld Instruments MP3 Players Digital Cameras

LED DRVR Module 1-CH IP67 36V 2.65A

LED DRVR Module 1-CH IP67 54V 2.3A