Diodes Incorporated announced the AL1676. This universal AC-input LED driver is designed to meet or exceed worldwide power-factor regulations for non-dimmable retrofit LED bulbs and tube lighting, providing a design that also delivers high efficiency and a low BOM cost. Options for the integrated MOSFET allow for 300 V to 650 V drain voltages and 1 A to 4 A drain currents in order to suit most 3 W to 18 W bulb requirements.
High power-factor operation is achieved with a single-stage buck converter topology, which uses constant on-time control and a simple closed loop to ensure the AL1676 delivers an accurate constant LED output current with good line and load regulation. Operating in boundary conduction mode eases EMI/EMC design requirements while the ability to detect off-time helps eliminates the need for an auxiliary winding, contributing to the device’s very low BOM count and cost.
The AL1676 includes multiple protection features such as under- and over-voltage, over-temperature and thermal fold-back that all help to increase system reliability within the high ambient temperatures encountered in an LED bulb. The high level of integration coupled with a small 5 mm × 6 mm SO-7 package also enable a very compact solution size, reusing the same design footprint for different wattage bulbs by virtue of the MOSFET options.
