LS7231-7234 Datasheet PDF - LSI Computer Systems

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 half cycle, 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.

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)

APPLICATIONS:
1. Foot-Switch Dimmer for large floor lamps.
2. Hand-Switch Dimmer for end-table lamps.