Driving the LEDs can be in parallel and/or series connections. The series method features inherent matching, but requires a higher supply voltage. For generating high voltages, an inductor-based converters are commonly used for this purpose.
The MAX8596Z switching regulator is designed to drive up to eight white LEDs in series, as shown in the above picture. When choosing this type of converter, the output voltage rating of the Lx pin must be considered. An overvoltage lockout threshold of 32V to 36V protects the IC if an LED becomes open circuit.
The device has a 2.6V to 5.5V input voltage range allowing the IC to be powered from a single lithium battery or three NiCd/NiMH batteries.
