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.