Demonstration circuit 876 is a dual step-up white LED driver with wide dimming range featuring the LT3486. The board is optimized to drive a string of six, eight, or ten white LEDs at 100mA from each of its two outputs with a PVIN input voltage range of 3V to 25V. The maximum LED output voltage must be less than 36V as the overvoltage protection at the output will limit the maximum output voltage to 36V in the case of an open circuit load. The high input voltage range, high-efficiency low-side internal 1.3A NPN power switches, ground-referenced low-voltage current sense resistors, PWM pins for 1000:1 dimming ratio, control pins for brightness adjust, overvoltage protection, shutdown control pin, externally programmable switching frequency, low shutdown current and internal soft-start capacitor make the LT3486 an extremely powerful and versatile LED driving IC for portable applications and displays.

temperature range.APPLICATIONS Advanced TVs PDP HDTVs LCD TVs (HDTV ready) LCD/DLP? rear

Demonstration circuit 2339A is a high current synchronous step-down LED driver featuring the LT3744. The unique drive stage used on the LT3744 allows the anodes of three LEDs to be connected together for better heat sinking in both the step-down configuration and the inverting buck-boost configuration (shown in a separate demonstration circuit DC1930A). The pros and cons of each configuration can be found in the data sheet.  The DC2339A targets high power LEDs and laser diodes (not included). The 3 LEDs are driven from the same output, but each LED is individually controlled. The input voltage range is 5.5V to 30V.

Demonstration circuit 1166 is a 48V Buck-Mode LED Driver featuring the LT3590. The LT3590 is a fixed frequency buck mode converter specifically designed to drive up to 10 LEDs in series at up to 50mA LED current. Series connection of the LEDs results in uniform LED brightness, eliminating the need for ballast resistors. The demo board targets 48V power applications but has a wide 4.5V to 54V (55V absolute max) input voltage range.

Demonstration circuit 1137 is a 20mA Six White LED Driver and OLED driver with Integrated Schottky featuring the LT3498. The LT3498 is a dual output boost converter featuring a 2.3MHz PWM LED driver and a PFM (Pulse Frequency Modulation) OLED driver. The demo board is designed to operate from 3V to 5V, ideal for Li Ion battery powered dual display applications, such as main and sub-displays for cell phones. The demo board offers flexible LED dimming methods. Users can use DC dimming, filtered PWM dimming or direct PWM dimming. The parts functions as a “one-wire” current source from the LED string point of view. The circuit protection clamps LED driver output to 27V (typ) if an open circuit condition occurs. When CTRL2 is higher than 1.5V, the demo board OLED supply output voltage is 16V. It can deliver up to 24mA from a 3V source.

Demonstration circuit 1288 is a Triple Boost or Buck-Boost LED Driver featuring the LT3496EUFD (for evaluating an LT3496 buck mode LED driver, use the demonstration circuit 986). The LT3496 is a triple output DC/DC converter designed to operate as current sources for driving high current LEDs. The board can be configured as either a buck-boost (default) or boost solution. The current for each output is set at 200mA in either mode. The three LEDs are included in the demo board assembly. The operating power input voltage (PVIN) range is 8V to 16V. The buck-boost circuit can tolerate an input voltage up to 40V when the LED string is on the high side. The part shuts down when the overvoltage threshold is reached. For a typical application with 5 LEDs totaling 16V of LED voltage, the circuit will operate until PVIN reaches 22V if the overvoltage protection is set to 38V.

Demonstration circuit DC2247A is a synchronous 2MHz boost LED driver featuring the LT®3922. The LT3922 features a low EMI Silent Switcher architecture and an optional spread spectrum frequency modulation (SSFM) that further reduces EMI. It has a 2A/36V internal power switch, but the demo board has been configured to use a 4V to 28V input and thus has input overvoltage lockout set at 28V. It drives a single string of LEDs at 330mA up to 34V when the input voltage is between 7V and 28V. DC2247A comes with low EMI features including optimized layout, SSFM, and input and output filters. It passes CISPR 25 class 5 conducted and radiated EMI. The LT3922 is protected against both open and short LED conditions and reports these faults. It also includes thermal shutdown.

Demonstration Circuit 395A is a Low Noise, Charge Pump White LED Driver featuring the LTC3202. The LTC3202 is a fractional charge pump LED driver that operates from 2.7V to 4.5V (3.3V nominal) and provides up to 125mA of LED current. The demo board includes 6 white LEDs in parallel, supplying approximately 20mA of current per LED.  Controls pins D0 and D1 set the values for the internal 2-bit DAC, which allows LED current to be adjusted for LED brightness control.

Demonstration circuit 1187 is an RGB LED Driver and Charge Pump featuring the LTC3212. The LTC3212 is a low noise boost charge pump capable of driving three LEDs at up to 25mA each. The charge pump operates in either 1x or 2x mode, with automatic mode switching. Individual current sources allow each LED to be turned on individually, in combination with the other LEDs, or in white mode using a single wire interface. The demo board input voltage range is 2.7V to 5.5V. White mode optimizes the red, green, and blue current settings to provide the best white color. LED currents are regulated using internal low dropout current sources. Automatic mode switching optimizes efficiency by switching modes only when a dropout is detected.

Demonstration circuit 1406A features three LT3746's, a 32-channel 20mA LED driver with buck controller and serial interface. The three LT3746’s are connected in series to control 32 OSRAM RGB LEDs stuffed on the demo board. Each IC drives a separate color. The demo board input voltage range is 9V to 40V and the LED output voltage is 4.2V for the blue and green LEDs, and 3V for the red LEDs. Each channel has an individually adjustable 12-bit (4096-step) grayscale PWM dimming control and a 6-bit (64-step) dot correction current adjustment.  Individual open/short LED and overtemperature flags are sent back during status read-back.  The evaluation software installed in a host computer communicates with the DC1406A via the interface board DC590B, an USB serial controller.