LS7217

LSI/CSI LS7217   LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631)271-0400 FAX (631) 271-0405                            PHOTO CONTROLLED OUTDOOR LIGHTING WITH PROGRAMMABLE TIMER Sep 2014 FEATURES: Input interface to a LDR or a photo transistor Programmable Duration Selection Shunt regulator 50Hz / 60Hz time base selection Relay Driver output 6.0V ± 0.75V operating voltage range (VDD – VSS) LS7217 (DIP), LS7217-S (SOIC) – See Figure 1 PIN ASSIGNMENT APPLICATIONS Lighting control for outdoor area lighting, street lighting, parking lot lighting, billboards lighting DESCRIPTION The 7217 is a programmable Timer IC designed to turn on a relay at night and turn off the relay at dawn or after a selectable number of hours. Figure 2 shows a typical application schematic. PIN DESCRIPTION: The following describes the operation of the inputs and outputs of the IC. FIGURE 1 The Time Select Table is as follows: TS1 TS2 00 01 10 11 Time Duration 4 Hours 6 Hours 8 Hours Dusk-to-Dawn VDD (Pin 2) VDD is the supply voltage positive terminal. It is regulated internally in the IC. The internal voltage regulator produces 6.0V ± 0.75V. Dusk-to-Dawn duration is determined solely by the photo-cell; i.e., the Relay output is on whenever the photocell recognizes an ambient dark condition. VSS (Pin 6) VSS is the supply voltage negative terminal. 50Hz / 60Hz SELECT Input (Pin 8) A high at this input selects the correct timing for 50Hz operation. Float...