An application note from Texas Instruments, white LED driver with digital and PWM brightness control (PDF!):
With a 40-V rated integrated switch FET, the TPS61160/1 is a boost converter that drives LEDs in series. The boost converter runs at 600kHz fixed switching frequency to reduce output ripple, improve conversion efficiency, and allows for the use of small external components.
The default white LED current is set with the external sensor resistor Rset, and the feedback voltage is regulated to 200mV, as shown in the typical application. During the operation, the LED current can be controlled using the 1-wire digital interface ( Easyscale™ protocol) through the CTRL pin.