Description

The A8511 is a multioutput WLED/RGB driver for backlighting medium-size displays. It is a fully integrated high-brightness (HB) LED driver solution that does not require external power devices to complete the backlighting design criteria. The A8511 integrates FETs for a boost converter as well as four 150 mA current sinks, offering a complete integrated solution at HB LED current levels. LED channels can be tied together for up to 600 mA sink capability. It can work from a single power supply of 6.8 to 21 V and withstand up to 40 V. The boost converter is a constant frequency, current-mode converter.

Features and Benefits

▪ Four LED sinks rated for 150 mA each (600 mA total)

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

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

▪ Internal bias supply for single-supply operation (VIN= 6.8 to 21 V)

▪ 3.5 μA shutdown current—limits battery drain

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

▪ 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