LS7234

LSI/CSI UL ® LS7231-7234 (631) 271-0400 FAX (631) 271-0405 December 2000 LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 A3800 TOUCH CONTROL LAMP DIMMER FEATURES: Phase-lock loop synchronization allows use in Wall Switch applications. Provides brightness control of incandescent lamps with touch plates or mechanical switches. Controls the "duty cycle" from 23% to 88% (conduction angles for AC half-cycles between 41˚ and 158˚, respectively.) Operates at 50Hz/60Hz line frequency. Extension input for remote activation. Input for slow dimming. +12V to +18V DC Power Supply voltage. (VSS - VDD) LS7231 to LS7234 (DIP) - See Figure 1 LS7231-S to LS7234-S (SOIC) DESCRIPTION: LS7231 through LS7234 are a series of monolithic, MOS integrated circuits designed for the control of brightness of incandescent lamps. The outputs of these ICs control the brightness of a lamp by controlling the firing angle of a triac connected in series with the lamp. All internal timings are synchronized with the line frequency by means of a built-in phase-lock loop circuit. The output occurs once every half-cycle of the line frequency. Within the halfcycle, the output can be positioned anywhere between 158˚conduction angle for maximum brightness and 41˚ conduction angle for minimum brightness in relation to the AC line frequency. The positioning of the output is controlled by applying a low level at the SENS input or a high level at the EXT input. These functions may b...