Description

The A8500 is a multi-output WLED driver for medium display backlighting. The A8500 integrates a boost converter and eight current-sinks to provide a flexible WLED/RGB backlight driver. The boost converter can provide output voltage up to 47 V. The flexible channel selection control and high voltage capability allow a wide range of LED backlight applications. The A8500 can support any application requiring 4 to 96 WLEDs. The boost converter is a constant frequency current-mode converter.

Features and Benefits

▪ Active current sharing between LED strings for ±1.5 typical current matching and ±1.2 typical accuracy

▪ Drive up to 12 series × 8 parallel = 96 LEDs (Vf = 3.2 V, If = 20 mA)

▪ Flexible dimming, using alternative methods:

▫ LED duty cycle control (PWM pin)

▫ DC current using serial programming (EN pin)

▫ DC current using external PWM signal (APWM pin)

▫ An external resistor

▪ Boost converter with integrated 50 V, 2 A DMOS

▪ LED sinks rated for 30 mA

▪ 200 kHz to 2 MHz switching frequency

▪ Open LED disconnect

▪ Boost current limit, thermal shutdown, and soft start

▪ No audible ceramic capacitor noise during PWM dimming

▪ Adjustable overvoltage protection (OVP)

▪ No pull-up resistors required for LED modules that use ESD capacitors

Applications include:

▪ Thin notebook displays

▪ LCD TV

▪ RGB backlight

▪ GPS systems

▪ Portable DVD players