Allegro MicroSystems Announces New High Power LED Driver For Medium LCD Display Backlighting

Allegro’s 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.



Operating frequency can be set up to 2 MHz in order to avoid interference with the AM radio band in automotive applications. The integrated boost DMOS switch is rated for 40 V at 3.6 A. PWM dimming allows LED currents to be controlled at up to a 1000:1 ratio. Additional 4:1 dimming can be achieved by using the DIM pin. As part of an extensive list of protection features, the A8501 provides protection against output connector shorts through an integrated output disconnect switch. It also includes adjustable overvoltage protection (OVP) and protects against open or shorted LEDs and an open OVP resistor or boost diode.



The device is supplied in a surface mount, 28-pin TSSOP package (suffix LP), with exposed thermal pad for enhanced thermal dissipation. It is available with an ambient operating temperature of either 125°C or 85°C maximum, for automotive or industrial/consumer applications. The device is lead (Pb) free, with a leadframe plating choice of 100% matte-tin (suffix T) or tin-bismuth (suffix B).