Demonstration circuit 850A is a Boost LED Driver featuring the LTC3783 a boost/SEPIC/flyback LED driver controller. The demo board requires a 3V to 14.4V input and provides 360mA LED current at up to 25V. It incorporates an output overvoltage protection feature to limit output voltage to less than 27V if the LED string is inadvertently disconnected. The LT3783 features 1000:1 PWM dimming for brightness control and analog dimming control.

Demonstration circuit 986 is a Triple Step-Down LED Driver featuring the LT3496EUFD. The LT3496 is a triple output DC/DC converter designed to operate as current sources for driving high current LEDs. Each ofthe three regulators on the demo board is independently operated. The default current for each output channel is 500mA. The output current should not exceed the rated current of the LEDs used.  The maximum voltage of an LED string the demo board can drive is limited by the duty cycle and the input voltage of the LT3496. The maximum power input voltage (PVIN ) is 45V. As a result, each channel of the demo board can drive up to ~31V total LED voltage. The LT3496's input voltage range is 3V to 30V (with 40V transients), however to minimize power dissipation the demo board uses a 3V to 5.5V supply.

Demonstration circuit 1470 is a High Current Synchronous Step-Down LED Driver with Three-State Control featuring the LT3743EUFD. The demo board is optimized for 20A output from a 12V input. Being an LED driver, the output current is regulated until the output voltage reaches a programmed voltage limit. The voltage limit on this demo board is set to around 6V by resistors R5 and R6. The 6V is chosen because of the 6.3V voltage rating of the output capacitors. The ideal load to be used with this demo board is a single LED, such as PT120 from Luminus Devices. The input voltage range of the LT3743 is 6V to 36V; however, the demo board utilizes 30V MOSFETs to demonstrate best efficiency, so the maximum recommended input voltage is 24V for the demo board.

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.

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.

DC1542A: Demo Board for LT3596 60V Step-Down LED Driver.

DC1573A is an 8-Channel High Voltage Boost LED Driver featuring the LT3760. The LT3760 drives up to 100mA per string and has a maximum LED string voltage of 45V. The VIN terminal is powered from an 10V to 14V input supply and is distinct from the 24V PVIN supply (20V to 28V) for best thermal performance. Overvoltage protection is set at 55V in case the LEDs are removed from the circuit. If the LEDs are opened, the FAULT terminal output flag goes low and reports the fault condition.  If one or more of the 8 LED channels is not used, its LED pin or terminal should be tied to VOUT (LED+) to disable it. Multiple channels can be tied in parallel by tying their LED1-LED8 pins together.

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.

Demonstration Circuit 366A is a low noise constant frequency regulated charge pump featuring the 100mA output current LTC3200. The demo board accepts a 2.7V to 4.5V input voltage and drives six white LEDs in parallel, resulting in 16.6mA per LED. Ballast resistors are employed to provide more uniform light intensity fromr the paralleled LEDs.

DC1436A is a 16-Channel High Voltage Boost LED Driver featuring the LT3754. The LT3754 drives up to 50mA per string and has a maximum LED string voltage of 45V. The VIN terminal is powered from an 8V to 14V input supply and is distinct from the 24V PVIN supply (20V to 28V) for best thermal performance. Overvoltage protection is set at 55V in case the LEDs are removed from the circuit. If the LEDs are opened, the FAULT terminal output flag goes low and reports the fault condition. If one or more of the 16 LED channels is not used, its LED pin or terminal should be tied to VOUT (LED+) to disable it. Multiple channels can be tied in parallel by tying their LED1-LED16 pins together.