Austrian Microelectronics pushes LED backlight driver chip for mobile phone display

Austrian Microelectronics announced the launch of two LED backlight driver ICs, AS3674 and AS3490, for use in smartphone LCD displays. New products have the highest performance in the industry with peaks of up to 90%, including DC-DC converters and current sources. The PCB package is only 11.5 mm2 and requires only 4 external components. The AS3674 and AS3490 are well suited for smartphones and other mobile devices that make space a top priority.

The AS3674 backlight driver chip family complements the portfolio of austriamicroelectronics lighting management units. The single chip combines application processing performance such as backlighting, intelligent lighting, and ambient light sensors (ALS). The AS3674 is an efficient 2 Mhz DC-DC switching boost converter that controls five current sources, each driving two LEDs in series. Its new flexibility is set by an external resistor to control the LED's current, up to 25mA for a single channel. The AS3490 has the same functionality as the AS3674 but only includes three sets of LED channels.

The soft start feature makes the AS3674 easier to integrate into noise-sensitive radio frequency systems. The AS3674 is controlled by two input circuits and can also be controlled by a PWM circuit between 100 and 800 Hz to achieve a 1:2000 dimming ratio. The single-channel, two-LED configuration, combined with a 2 MHz converter operating frequency, enables the use of tiny external components such as 4.7 μH inductors and achieves up to 6% better efficiency than competitors.

The AS3674 operates from 2.5V to 5.5V and includes a range of safety features such as low voltage blocking, overcurrent and overtemperature protection, and LED testing. Both the AS3674 and AS3490 are available in a space-saving 12-ball WL-CSP package (1.7 x 1.4 x 0.5 mm, 0.4 mm high).