Driver Drives up to 6 Strings of 10 leds

The LT3598 can drive up to six strings of leds, each with up to 10 30mA white leds in series while delivering efficiencies up to 90%. Its multichannel capability makes it ideal for medium sized TFT-lcd backlighting applications. Its input voltage range of 3V to 30V makes it ideal for automotive and industrial applications. It offers 1.5% led current matching to insure uniform brightness of the display. Dimming ratios as high as 3,000:1 can be attained by using True Color PWM dimming. A programmable 200kHz to 2.5MHz fixed frequency operation and current mode architecture offers stable operation over a wide range of supply and output voltages while minimizing the size of the external components. Additionally, the switching frequency is synchronisable to an external clock. The LT3598 uses a single 1.5A, 45V internal switch to provide a boost mode constant current source. However, even when VIN exceeds VOUT, the LT3598 will continue to regulate the led current. The internal boost converter uses an adaptive feedback loop to regulate the output voltage slightly higher than the required led voltage to insure maximum efficiency. If any of the led strings experiences an open circuit, it will continue to regulate the existing strings and signals the OPENled alert pin. If higher current leds are required, multiple strings can be combined enabling it to drive up to 2 strings of 10 90mA leds. Additional features include programmable over voltage protection, led current derating based on junction temperature and/or led temperature and output voltage limiting when all led strings are disconnected.