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 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 5 x 6mm SO-7 package also enable a compact solution size, reusing the same design footprint for different wattage bulbs by virtue of the MOSFET options.
Power and pricing options (all 10,000) are in the SO-7 package are;
AL1676-20AS7-13 (2A/300V) … $0.110
AL1676-30AS7-13 (3A/300V) … $0.117
AL1676-10BS7-13 (1A/500V) … $0.120
AL1676-20BS7-13 (2A/500V) … $0.124
AL1676-20CS7-13 (2A/600V) … $0.132
AL1676-40DS7-13 (4A/650V) … $0.204