Description

The A8501 is a multioutput WLED/RGB driver for backlighting medium-size displays. The A8501 integrates a boost converter and four 100 mA current sinks. LED channels can be tied together for up to 400 mA sink capability. It can work from a single power supply of 8 to 21 V and withstand up to 40 V. The boost converter is a constant frequency, current-mode converter

Features and Benefits

▪ 600 kHz to 2.2 MHz switching frequency—ability to operate above the AM band

▪ Internal bias supply for single-supply operation (VIN = 8 to 21 V)

▪ Boost converter with integrated 40 V DMOS switch and OVP–load-dump protection

▪ 3.5 μA shutdown current—limits battery drain

▪ Active current sharing between LED strings for 0.8 current matching and 0.7 accuracy

▪ Drive up to 9 series LEDs in 4 parallel strings, 36 LEDs maximum (Vf = 3.5 V, If = 100 mA)

▪ LED sinks rated for 100 mA each (400 mA total)

▪ PWM dimming with LED PWM duty cycle control

▪ 4000:1 dimming range

▪ Extensive fault mode protection schemes:

▫ Shorted LED protection against misconnected loads—with true output disconnect

▫ Open LED disconnect protects against LED failures

▫ External thermistor sensing to limit LED temperature

▫ Output overvoltage protection (OVP): 19.5 V default can be adjusted as high as 38 V

▫ Open Schottky and open OVP resistor protection against external component failure

▫ Input under- and overvoltage protection (UVLO and OVLO) against VIN variation

▫ Boost current limit, output short circuit limit, overtemperature protection (OTP), and soft start

Applications include:

▪ GPS navigation systems

▪ Automotive infotainment

▪ Back-up camera displays

▪ Cluster backlighting

▪ Portable DVD players

▪ Industrial LCD displays