Diodes Incorporated announces the expansion of its automotive-compliant LED driver portfolio by introducing the AL8866Q. This DC-switching LED driver-controller drives an external MOSFET and supports buck, boost, buck-boost, and single-ended primary-inductance converter (SEPIC) topologies for high-power LED lighting systems. Applications include daytime running lights (DRL), high/low beams, fog lights, turn lights, brake/stop lights, and more.
It operates within a wide input power supply range from 4.7V to 85V, covering the common 12V, 24V, and 48V battery power rails. This flexibility and multi-mode operation enables lighting designers to standardise on a single component type, streamlining inventory and simplifying design processes.
The AL8866Q has a fixed-frequency (400kHz) peak current-mode control architecture. It incorporates a spread spectrum frequency modulation technique to enhance EMI performance, which is compliant with the most stringent CISPR 25 Class 5 standard.
The device supports analog and PWM dimming of the LED current via its DIM pin and has a 1% reference tolerance, enabling better brightness control and matching between lamps. With an over 100:1 analog dimming range, it achieves ±12% output current accuracy at low (20%) analog dimming levels, making it more precise than similar LED drivers available. Alternatively, PWM dimming (0.1 to 1kHz) achieves a 100:1 dynamic range.
The AL8866Q integrates a soft-start function, gradually increasing the inductor and switch current to minimise potential overvoltage and overcurrent at the output. It features an open-drain fault output to indicate various fault conditions, which include LED output-overvoltage, LED output-open/-short, cycle-by-cycle overcurrent protection, sense-resistor and shorted-inductor/-diode detection, diode-open circuit, and thermal shutdown.
