8弦白光LED驱动的SMBus和LCD背光应用PWM输入ADD5203

　　TheADD5203 is a whiteLEDdriver forbacklight applications based on high efficiency， current-mode， step-up converter tech-nology. It is designed with a 0.15 Ω， 2.9 A internal switch and apin-adjustable operating frequency between 350 kHz and 1 MHz.

　　The ADD5203 contains eight regulated current sources for uniform brightness intensity. Each current sourcecanbe driven up to 30 mA， and the LED driving current is pin adjustable by an external resistor. The ADD5203 drives up to eight parallel strings of multiple series connected LEDs with a ±1.5% current matching between strings.

　　The ADD5203 provides various dimming modes. Each dimming mode is selectable with an external dimming mode selection pin. The LED dimming control interface can be achieved through PWM input and/or SMBus. The deviceprovides adjustable output dimming frequency range from 200 Hz to 10 kHz by an external resistor and capacitor. The ADD5203 operates over an input voltage range of 6 V to 21 V， but the device can function with a voltage as low as 5.6 V.

　　The ADD5203 also has multiple safety protection features to prevent damage during fault conditions. If any LED is open or short， the device automatically disables the faulty current source. The internal soft start prevents inrush current during startup. Thermal shutdown protection prevents thermal damage.

　　The ADD5203 is available in a low profile， thermally enhanced， 4 mm × 4 mm × 0.75 mm， 28-lead， RoHS-compliant lead frame chip scale package （LFCSP_WQ） and is specified over the industrial temperature range of −25°C to +85°C..