High Power Factor LED Driver-Controller with Mixed-Mode Dimming


Diodes Incorporated’s AL1665 single-stage, fly-back and buck-boost controller for dimmable LED lighting installations operating at up to 100W.


The AL1665 is designed to drive an external MOSFET to control LED loads and maintain a high power factor. It provides a compact and efficient solution that helps minimize the use of additional components and maintains high switching efficiency.


Designed to operate from an AC input voltage of between 85VAC and 305VAC, the AL1665 utilizes primary side regulation (PSR) topologies, removing the need for optical isolation or secondary side control. With PSR, developers can design smaller solutions using less PCB area and achieve lower bill of material costs, while delivering constant current regulation to high-power LED lighting applications.


The ability to apply dimming across 0.5% to 100% of the high-power output makes the AL1665 suitable for commercial LED applications where the lighting output levels need to be adjustable to save power, or for aesthetic purposes like in retail displays. Compatible with ANSI-approved dimmers, the output voltage can be adjusted between 0V and 10V using a dedicated PWM input, or with an analog input voltage of between 0V and 2.5V, making it simple to develop connected lighting systems that can be managed both locally and remotely.


The device employs boundary condition mode (BCM) conversion with valley switching to minimize losses and deliver high efficiency with low EMI. The wide supply voltage allows the AL1665 to operate in any geographical region directly from the main supply, while its line and load regulation of less than ±2%, power factor of more than 0.9, and THD of less than 20% enables manufacturers to comply with all relevant legislation.


The AL1665 is available in the SO-8 package priced at $0.20 in 1000 piece quantities.