The AAT2404 is a highly integrated, high efficiency step-up controller for powering white LEDs used as backlights in large size LCD panels. To accommodate various LED configurations in both direct and edge lighting applications, the device uses a high voltage external Power MOSFET. The AAT2404 contains an integrated current sense architecture and eliminates the need for an expensive low resistance, high accuracy, sense resistor. The device operates ideally from a regulated 24V DC power supply, but can also operate off of a 12V DC power supply. The device output voltage is only limited by the breakdown voltage of the external Power MOSFET and is therefore suitable for edge lighting solutions where voltages up to 250V are generated to supply as many as 50 series connected LEDs.

The AAT2404 provides an output voltage regulated by the CSFB pin provided by the AAT2401, AAT2402S, AAT2403 or AAT2405 companion LED driver ICs. The CSFB pin is an analog voltage that represents the LED string with the highest voltage requirement. Regulating to this voltage allows a wide range of LED characteristics, while maintaining the lowest possible power dissipation. The CSFB regulation point can be set by adjusting a resistor to ground from the RSET pin.

The boost switching frequency is 400kHz to allow for optimum efficiency with the smallest external filter. Alternatively, the device switching frequency may be set with an external resistor to avoid sensitive frequency ranges in some applications. Current mode control provides fast response to line and load transients. Thermal protection circuitry shuts down the boost converter in the event of an over-temperature condition.

The AAT2404 is available in a Pb-free thermally enhanced 24-pin 3 x 4 TQFN package.