Options for the integrated MOSFET allow for 300V to 650V drain voltages and 1A to 4A drain currents in order to suit most 3W to 18W 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 to eliminate 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 help to increase system reliability within the high ambient temperatures encountered in an LED bulb. The high level of integration coupled with a small 5mm x 6mm 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.
