Description

LS7641 is a monolithic CMOS lamp dimmer IC designed for in line wall switch applications driving both LED and incandescent lamps. It uses Reverse Phase dimming technology wherein the brightness of a lamp is controlled by controlling the turn-off angle in ac half cycles using a FET. This is in contrast with Leading edge dimming technology wherein the brightness is controlled by varying the turn-on angle using a triac. Reverse Phase dimming produces total flicker free dimming down to extremely low brightness. It also eliminates the following problems associated with triac dimming when driving LED lamps:

• Acoustic and RFI noise
• Failure of the triac to latch due to load converter oscillation delay
• Flicker at low brightness due to insufficient holding current for the triac

Features:

• For use in wall switch dimmers driving ceiling lamps.
• Efficient dimming control for both LED and incandescent bulbs.
• Eliminates RFI associated with triac dimmers.
• Continuous analog dimming steps from 0 to 100% brightness.
• Achieves flicker free ultralow brightness for LED bulbs unachievable with triac dimmers.
• Overcurrent sense input for safety shutdown.
• Adjustable turn-on angle for compatibility with light bulbs of different characteristics.
• 50Hz/60Hz operation.
• 5V supply.
• Available in SOIC-14 and TSSOP-14