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

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

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”.

The LT3799 is an isolated flyback controller with power factor correction specifically designed for driving LEDs. The controller operates using critical conduction mode allowing the use of a small transformer. Using a novel current sensing scheme, the controller is able to deliver a well regulated current to the secondary side without using an opto-coupler. A strong gate driver is included to drive an external high voltage MOSFET. Utilizing an onboard multiplier, the LT3799 typically achieves power factors of 0.97. The FAULT pin provides notification of open and short LED conditions.The LT3799 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third winding to provide power to the part. An internal LDO provides a well regulated supply for the part?s internal circuitry and gate driver. TRIAC Dimmable LED Current Regulation LT3799 YES ?10% LT3799-1 NO ?5% Applications Offline 4W to 100W+ LED Applications High DC VIN LED Applications

The LT3954 is a DC/DC converter designed to operate as a constant-current source and constant-voltage regulator. It features an internal low side N-channel MOSFET rated for 40V/5A. The LT3954 is ideally suited for driving high current LEDs, but also has features to make it suitable for charging batteries and supercapacitors. The fixed frequency, current mode architecture results in stable operation over a wide range of supply and output voltages. A voltage feedback pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size.The LT3954 senses output current at the high side or at the low side of the load. The internal PWM generator can be configured to self-oscillate at fixed frequency with duty ratio programmable from 4% to 96%. When driven by an external signal, the PWM input provides LED dimming ratios of up to 3000:1. The CTRL input provides additional analog dimming capability.Applications High Power LEDs Output Short-Circuit Protected Boost Battery and SuperCap Chargers Accurate Current Limited Voltage Regulators

Full-Featured LED Driver with 2.3A Switch Current Features: 3000:1 True Color PWM™ Dimming Ratio 2.3A, 45V Internal Switch 100mV High Side Current Sense Open LED Protection Adjustable Frequency: 250kHz to 2.5MHz Wide Input Voltage Range: Operation from 3V to 30V Transient Protection to 40V Operates in Boost, Buck Mode and Buck-Boost Mode Gate Driver for PMOS LED Disconnect Constant-Current and Constant-Voltage Regulation CTRL Pin Provides 10:1 Analog Dimming Low Shutdown Current: <1μA Available in (4mm × 4mm) 16-Lead QFN and 16-Pin TSSOP Packages

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

4.5A Monolithic LED Drivers with True Color PWM Dimming Features: True Color PWM™ Dimming Delivers Constant LED Color with Up to 3000:1 Range Wide Input Voltage Range: 2.8V to 36V 4.5A, 60mΩ, 42V Internal Switch Drives LEDs in Boost, Buck-Boost or Buck Modes Integrated Resistors for Inductor and LED Current Sensing Program LED Current: 100mA to 1050mA (LT3478-1) (10mV to 105mV)/RSENSE (LT3478) Program LED Current De-Rating vs Temperature Separate Inductor Supply Input Inrush Current Protection Programmable Soft-Start Fixed Frequency Operation from 200kHz to 2.25MHz Open LED Protection (Programmable OVP) Accurate Shutdown/UVLO Threshold with Programmable Hysteresis 16-Pin Thermally Enhanced TSSOP Package

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 AD9983A is a complete 8-bit, 140 MSPS, monolithic analog interface optimized for capturing YPbPr video and RGB graphics signals. Its 140 MSPS encode rate capability and full power analog bandwidth of 300 MHz support all HDTV video modes up to 1080i and 720p as well as graphics resolutions up to SXGA (1280 × 1024 at 75 Hz).The AD9983A includes a 140 MHz triple ADC with an internal reference, a PLL, and programmable gain, offset, and clamp control. The user provides only a 1.8 V power supply and an analog input. Three-state CMOS outputs can be powered from 1.8 V to 3.3 V. The AD9983A on-chip PLL generates a sample clock from the tri-level sync (for YPbPr video) or the horizontal sync (for RGB graphics). Sample clock output frequencies range from 10 MHz to 140 MHz. With internal coast generation, the PLL maintains its output frequency in the absence of sync input. A 32-step sampling clock phase adjustment is provided. Output data, sync, and clock phase relationships are maintained. The auto-offset feature can be enabled to automatically restore the signal reference levels and to automatically calibrate out any offset differences between the three channels. The auto channel-to-channel gain matching feature can be enabled to minimize any gain mismatches between the three channels. The AD9983A also offers full sync processing for composite sync and sync-on-green applications. A clamp signal is generated internally or may be provided by the user through the CLAMP input pin. Fabricated in an advanced CMOS process, the AD9983A is provided in a space-saving 80-lead, Pb-free, LQFP surface-mount plastic package, and is specified over the 0°C to 70°C temperature range.APPLICATIONS Advanced TVs Plasma display panels LCDTV HDTV RGB graphics processing LCD monitors and projectors Scan converters