LM27961

LM27961 Dual-Display White LED Driver with 3/2x Switched Capacitor Boost November 2004 LM27961 Dual-Display White LED Driver with 3/2x Switched Capacitor Boost General Description The LM27961 is a charge-pump-based white-LED driver that is ideal for mobile phone display backlighting. It is intended to drive 4 LEDs for a main phone display backlight and 3 LEDs for a sub-display backlight. Regulated internal current sources deliver excellent current and brightness matching in www.DataSheet4U.com all LEDs. The LED driver current sources are split into two independently controlled groups. The primary group (Group A) can be used to backlight a main phone display with up to 4 LEDs. The low-side current drivers of Group A accommodate common-anode-type LEDs. The second group (Group B) can backlight a secondary display with up to 3 LEDs. The high-side current drivers of Group B accommodate commoncathode-type LEDs. Both Group A and Group B can also drive standard two-terminal LEDs, and provide other general lighting functions (keypad lighting, fun lighting, etc). The brightness of the two LED groups can be adjusted independently with external resistors. The LM27961 works off an extended Li-Ion input voltage range (2.7V to 5.5V). Voltage boost is achieved with a highefficiency 3/2x-gain charge pump. The LM27961 is available in National’s chip-scale 18-bump micro SMD package. Features n Drives 4 Individual Common-Anode LEDs with up to 20mA each for a Main Display Backlight n Drives 3 ...