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.