Single-string white LED driver IC for LCD backlighting



Click on image to enlarge

The new A8513 from Allegro MicroSystems Europe is a single-output white LED driver IC designed for backlighting applications in LCD displays for automotive and consumer applications and their associated application, performance, and protection requirements. The new device, which integrates a current-mode boost converter with an internal power switch and one current sink, is designed to provide a robust solution for applications such as automotive infotainment, cluster and centre-stack lighting, industrial LCD displays, portable DVD players, flatbed scanners, and LED lighting. The A8513 can operate from a single power supply from 4.5 to 40 V to accommodate start/stop, cold-crank and load-dump requirements. The 2 MHz switching frequency of the boost converter allows the device to operate above the AM radio band. The new device features robust FMEA (failure modes & effects analysis) performance, and constantly monitors the state of the system to determine if any fault conditions occur, with a fault flag pin alerting the controller to possible fault conditions. If required, the fault flag can be used as part of a circuit to drive an external p-type FET to disconnect the input supply from the system in the event of a fault. Built-in protection is provided against output short-circuit and overvoltage, open or shorted diode, open or shorted LED pin, shorted boost switch or inductor, shorted current-setting resistor, and IC overtemperature. A dual-level cycle-by cycle current limit function provides soft start and protects the internal current switch against high-current overloads. The A8513 is supplied in both eMSOP-10 and eTSSOP-16 packages. Various oscillator frequencies are available to meet customer requirements.