The ADD5205 is a white LED driver for backlight applications based on high efficiency, current mode, step-up converter technology. It is designed with a 0.3 Ω internal switch and 1 MHz fixed operating frequency. The ADD5205 contains four regulated constant current sources for uniform brightness intensity. Each current source is capable of driving up to 25 mA.

The ADD5205 has four parallel strings of multiple series connected LEDs with ±2% current matching. The device provides adjustable current sources that drive up to 25 mA using an external resistor. The LED current can be controlled by a PWM signal input on the PWM pin. An internal circuit translates the PWM signal to an analog signal with an external capacitor and linearly controls the LED current.

The ADD5205 has multiple safety protection features to prevent any damage during fault conditions. If one or more LEDs are open, the device disables the faulty current regulator automatically. The internal soft start prevents inrush current during startup. A thermal shutdown protection feature prevents thermal damage.

The ADD5205 is available in a low profile, thermally enhanced 3 mm × 3 mm × 0.75 mm, 12-lead lead frame chip scale package (LFCSP) and is specified over the temperature range of −25°C to +85°C.

APPLICATIONS

• Smart PCs, PMPs, tablet PCs, UMPCs, and notebooks