High-efficiency fault-tolerant LED driver with wide input voltage range

The new A8515 from Allegro MicroSystems Europe is a multi-output white LED driver for LCD backlighting in consumer and industrial displays.



The device can operate from a single power supply over a wide input voltage range (from 5 to 40 V), and incorporates advanced protection features to provide a high degree of fault tolerance for optimised viewing.



The A8515 integrates a current-mode boost converter with internal power switch and two current sinks that can drive up to 24 LEDs at 120 mA. The two LED current sinks can also be paralleled together to achieve LED currents up to 240 mA. The low 720 mV regulation voltage on LED current sources reduces power loss and improves efficiency.



An external pulse-width modulation (PWM) signal applied to the PWM dimming input pin is used to control the LED intensity. The device also integrates a driver for an optional external input disconnect switch.



The A8515 incorporates 'best in class' protection features including open or short-circuit LED pin protection, open Schottky protection, cycle-by-cycle current limiting, over-temperature protection and output short-circuit protection. A comprehensive fault table is included in the data sheet covering the leading-edge performance and protection features of the A8515.



The A8515 is available in an eTSSOP-16 package (suffix LP) with an exposed thermal pad. It is lead (Pb) free, with 100% matt tin lead-frame plating.