The ISL97901 is a highly efficient four channel, 1. 5A sequential LED driver powered from a single-cell Li-ion battery, or regulated input voltage up to 5. 5V. The ISL97901 incorporates an independent current controlled driving mechanism for each of the LEDs to allow accurate brightness control. The ISL97901 also utilizes a buck-boost converter to ensure optimum output voltage is maintained for a wide variety of LED forward voltages. The ISL97901's highly integrated and efficient power conversion core operates at well over 90% efficiency across a wide range of operating conditions. The power conversion core implements a proprietary algorithm that allows seamless transitions and glitch-free operation between the buck and the boost modes as the battery voltage drops during operation. The ISL97901 provides I/O pins to interface with Intersil's optical sensor IC's for white balance control. White balance is achieved by closing the opto-electrical loop which allows for LED light output to get calibrated against preset target values. The ISL97901 can also be configured to run in an open-loop manner if real-time white balance control is not desired. In this case, the LED currents are set by the internal registers.