Boost/SEPIC controller enables LED-wide PWM dimming in automotive applications

Diodes Incorporated has released a boost/SEPIC controller for various automotive LED applications. The AL8853AQ is an automotive-compliant and highly integrated boost/SEPIC controller that supplies high performance with a reduced BOM in automotive LED applications, including exterior lights, headlamps, HUDs, and backlight displays.

Automotive headlamp manufacturers can employ SEPIC topology to allow high or low-beam LED array drivers that work directly from a vehicle's battery instead of utilising the conventional two-stage topology of a boost followed by a buck converter or a full-bridge buck-boost topology. The SEPIC functionality of the device supports cost-effective, simple buck-boost-like topology, which is ideal for HUD systems, a popular feature in automotive designs.

The device's wide input range (6V to 40V) supports a typical 12V vehicle battery voltage input. Its 200mV feedback reference voltage has ±3% tolerance to maintain tight brightness control while enhancing efficiency. The fixed 400kHz switching frequency of the device supports low EMI by employing a fundamental frequency outside the MW band. Also, this controller's fast (50kHz) PWM to analog dimming mode (100% down to 1%) prevents visible low or high-frequency flickering usually associated with PWM dimming. The device also incorporates robust protection features to protect against unexpected overvoltage, overcurrent, overtemperature, and diode and inductor short-circuit events.