Demonstration circuit 773 is a synchronous buck-boost white LED driver featuring the LTC3441 and LTC2050. The board is optimized for 3.9V LED forward voltage output at 1000mA load current and a single lithium-ion input voltage range of 3V to 4.2V. the demo board drives a Luxeon III white LED (included on-chip). With its high 1MHz switching frequency, synchronous buck-boost internal power switches, low quiescent current and thermally enhanced package, the LTC3441 is a very versatile and powerful IC for driving high power white LEDs like the Luxeon III from a lithium-ion battery. The LTC2050 is used for constant current control and to adjust the LED current.
The LED pushbutton is used to manually turn on the LED. The SHDN terminal can be used to program pulses of light from an external source for certain flash applications. The DIM terminal can be used to program the LED for dimmer operation than 1A LED current using a external PWM signal.