Automotive Qualified LED Driver : AL8866Q

Hedy · Dasenic Feb 06,2025 62

The AL8866Q is a high-efficiency buck LED driver from Diodes Incorporated designed to drive high-brightness LEDs.

This DC-switching LED driver controller drives an external MOSFET and supports buck, boost, buck-boost, and single-ended primary-inductor converter (SEPIC) topologies for high-power LED lighting systems. Applications include daytime running lights (DRLs), high and low beams, fog lights, turn signals, brake/parking lights, etc.

The AL8866Q operates over a wide voltage range of 4.7V to 85V, covering common 12V, 24V, and 48V battery rails. Flexible voltage selection and multi-mode operation allow lighting designers to standardize on a single component type, streamlining inventory and simplifying the design process.

The AL8866Q features a fixed frequency (400kHz) peak current mode control architecture and uses Spectrum Frequency Modulation to improve EMI performance, meeting the most stringent CISPR 25 Class 5 standard.

The AL8866Q uses a DIM pin to support LED current analog dimming and PWM dimming with a 1% reference tolerance, which allows for better brightness control and improved matching between lamps. This driver has an analog dimming range greater than 100:1, achieving ±12% output current accuracy at low analog dimming levels (20%), which is more accurate than similar LED drivers. PWM dimming (0.1 to 1kHz) can achieve a 100:1 dynamic range.

The AL8866Q has a built-in soft-start function that smoothly increases the inductor and switch currents to minimize possible overvoltage and overcurrent conditions at the output. The device features an open-drain fault output that indicates a variety of fault conditions, including LED output overvoltage, LED output open/short, cycle-by-cycle overcurrent protection, sense resistor and shorted inductor/diode detection, diode open, and thermal shutdown.

The AL8866Q is available in SO-8EP and U-DFN3030-10 packages and operates over the -40°C to +125°C temperature range. The AL8866QSP-13 (SO8-EP) and AL8866QFN-7 (U-DFN3030-10) are available now. A standard specification version of the AL8866 is also available for industrial and commercial product applications.

Feature(s)

• AEC-Q100 (Grade 1)

• Wide Input Voltage Range from 4.7V to 85V

• Pre-Fixed 400kHz Switching Frequency (Factory Set)

• Spread Spectrum Frequency Modulation for Low EMI

• Analog Dimming Range: 1% to 100%

100% Dimming Level ±3% Current Accuracy

20% Dimming Level ±12% Current Accuracy

• PWM Dimming Ratio 100:1 at 200Hz PWM Frequency

• Programmable Soft Start

• Fault Status Indicator for Protections

• Output Overvoltage and LED Open Circuit Protection

• Output Undervoltage and LED Short Circuit Protection

• Cycle-by-Cycle Overcurrent Limitation Protection

• Sense Resistor Shorted Circuit Protection

• Diode/Inductor Shorted Circuit Protection

• Diode Open Circuit Protection

• Thermal Shutdown

• Totally Lead-Free & Fully RoHS Compliant

• Halogen and Antimony Free. “Green” Device

• The AL8866Q is suitable for automotive applications requiring specific change control; this part is AEC-Q100 qualified, PPAP capable, and manufactured in IATF 16949 certified facilities.