Diodes Incorporated has expanded its automotive-compliant LED driver portfolio with the AL8891Q – an easy-to-use synchronous buck LED driver with high-side current sense drives up to 2A from a wide 4.5-65V input voltage range.
The driver supports up to 95% duty cycle, allowing the drive of longer LED chains. Designed to provide a flexible, high-efficiency solution for automotive lighting applications, the driver is suitable for use in daytime running lights, fog lights, turn lights, brake lights and interior lights.
Built on constant-on-time control, the AL8891Q enables simple control-loop compensation and cycle-by-cycle current limiting with a fast transient response without requiring an external compensation capacitor. With an adjustable switching frequency of 200kHz to 2.5MHz, the driver optimises efficiency while achieving a smaller inductor size and compact form factor. Incorporating a spread spectrum frequency modulation technique, the driver enhances EMI performance in order to comply with the most stringent CISPR 25 Class 5 standard.
The AL8891Q has two independent rings – PWN and analogue dimming – for enhanced functionality. PWN dimming, from 0.1kHz, is suitable for high-resolution dimming, while analogue dimming is from 0.15V to 2V. The driver features an internal soft-start function which gradually increases the inductor and switch current to minimise potential overvoltage and overcurrent at the output.
Additionally, the device features comprehensive protections with fault reporting, including thermal shutdown with auto-restart, input and constant current undervoltage lockout (UVLO), cycle-by-cycle current limit, and LED-open and short circuit protection to help increase system robustness.
The AL8891Q is available in a thermally-enhanced TSSOP-16EP package with an operating temperature range of -40°C to +125°C, and in a standard compliance version - AL8891 – which is designed for industrial and commercial applications.
