UL
廬
LSI/CSI
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
LSI
LS7534
LS7535
(631) 271-0400 FAX (631) 271-0405
A3800
DIMMER LIGHT SWITCH
WITH UP AND DOWN CONTROLS
FEATURES:
鈥?Phase-lock loop synchronization allows use as a
Wall Switch
鈥?Brightness control of incandescent lamps with touch
plates (LS7534) or mechanical switches (LS7535)
鈥?Dual Controls eliminate confusion
鈥?Soft turn-on /turn-off
鈥?Controls the "Duty Cycle" from 23% to 88%
(conduction angles for AC half-cycles between 41擄
and 159擄, respectively)
鈥?Operates at 50Hz/60Hz line frequency
鈥?Input for slow dimming
鈥?+12V to +18V DC supply voltage (V
SS
- V
DD
)
鈥?LS7534/LS7535 (DIP);
LS7534-S/LS7535-S SOIC - See Figure 1
August 1996
CONNECTION DIAGRAM
- TOP VIEW
V
SS
(+V)
1
8
TRIG
DOZE
2
7
V
DD
(-V
)
LS7534
CAP
3
6
DOWN
SYNC
4
5
UP
FIGURE 1
DESCRIPTION:
LS7534/LS7535 are monolithic, MOS integrated cir-
cuits that are designed for brightness control of in-
candescent lamps. The outputs of these ICs control
the brightness of a lamp by controlling the firing an-
gle of a triac connected in series with the lamp. All
internal timings are synchronized with the line fre-
quency by means of a built-in phase-lock loop cir-
cuit. The output occurs once every half-cycle of the
line frequency. Within the half-cycle, the output can
be positioned anywhere between 159擄 conduction
angle for maximum brightness and 41擄 conduction
angle for minimum brightness in relation to the AC
line frequency. The positioning of the output is con-
trolled by applying the proper logic levels at the UP
and DOWN inputs.
These functions may be implemented with very few
interface components which is described in the ap-
plication examples (See Fig. 5A and 5B). For touch
plates, LS7534 is used (Fig. 5A). For mechanical
switches, LS7535 is used (Fig. 5B).
In the following Operating Description of the applica-
tion examples, an Activation is Touch for LS7534
and Switch Closure for LS7535.
Short Activation
(34ms to 325ms)
UP
- When the lamp is off, if a short activation is applied to
the UP input, the lamp brightness is ramped up to full-on or
to a previous brightness stored in the memory. The ramp-
up time from off to full-on is 2.8 sec. The ramp-up time from
off to any other brightness is proportionally shorter. When
the lamp is on at any brightness, a short activation applied
to the UP input has no effect.
DOWN
- If a short activation is applied to the DOWN input,
the lamp brightness is ramped down to off. The ramp-down
time from full-on to off is 5.6 seconds. The ramp-down time
from any other brightness is proportionally shorter. When
the lamp is off, a short activation applied to the DOWN input
has no effect.
Long Activation
(Greater than 334ms)
UP
- If a long activation is applied to the UP input, the lamp
brightness ramps up from the pre-activation brightness as
long as the activation is maintained or until the full bright-
ness is reached. At full brightness any continued long ac-
tivation has no further effect.
DOWN
- If a long activation is applied to the DOWN input,
the lamp brightness is ramped down as long as the long ac-
tivation is maintained or until the minimum brightness is
reached. At minimum brightness, any continued long ac-
tivation has no further effect. When the lamp is off, a long
activation applied to the DOWN input has no effect.
7534/35-080796-1
1
2
3
4
5
6
7
8
