LSI/CSI
UL
廬
LS7232ND
(631) 271-0400 FAX (631) 271-0405
January 2003
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
A3800
TOUCH CONTROL LAMP DIMMER
FEATURES:
鈥?Phase-lock loop synchronization
allows use in Wall Switch applications.
鈥?Provides brightness control of incandescent lamps
with touch plates or pushbutton switches.
鈥?Controls the duty cycle from 23% to 88%
(conduction angles for AC half-cycles
between 41藲 and 158藲, respectively.)
鈥?Operates at 50Hz/60Hz line frequency.
鈥?Extension input for remote activation.
鈥?+12V to +18V Power Supply voltage (V
SS
- V
DD
).
鈥?LS7232ND (DIP); LS7232ND-S (SOIC ) - See Figure 1
DESCRIPTION:
LS7232ND is a MOS integrated circuit designed to control
brightness of incandescent lamps. The output of this IC controls
the brightness of a lamp by controlling the firing angle of a triac
connected in series with the lamp. All internal timings are syn-
chronized 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 posi-
tioned anywhere between 158藲conduction angle for maximum
brightness and 41藲 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.
These functions may be implemented with very few interface
components, as shown in Figure 5. When implemented in this
manner, touching of the Touch Plate causes the lamp brightness
to change as follows:
1.
If the Touch Plate is touched momentarily (42ms to 333ms),
the lamp is:
a) turned off if it was on,
b) turned on if it was off.
The brightness resulting is either full brightness or,
depending on the mode, a previous brightness stored in the
IC memory.
If the Touch Plate is touched for a prolonged time
(more than 342ms) the light intensity changes slowly. As
long as the touch is maintained, the change continues; the
direction of change reverses whenever the maximum or
minimum brightness is reached.
PIN ASSIGNMENT - TOP VIEW
LSI
1
2
LS7232ND
3
4
FIGURE 1
V
SS
(+V)
MODE
8
TRIG
V
DD
(-V)
7
CAP
SYNC
6
5
EXT
SENS
MODE Input
V
DD
Vss
Float
Mode
0
1
2
Functional Equivalent*
LS7231
LS7232
LS7233
*NOTE:
The LS7232ND can replace LS7231, LS7232 and
LS7233 where the DOZE input is not used. The LS7232 PCB
requires no change. The LS7233 PCB requires that the Pin 2
connection be opened. The LS7231 PCB requires that the Pin
2 connection be made to V
DD
instead of Vss.
CAP
(Pin 3)
The CAP input is for the PLL filter capacitor.
A 0.047碌F capacitor should be connected to this input.
SYNC
(Pin 4)
The AC Line Frequency is applied to this input through an ex-
ternal RC circuit (See Figure 5). The Phase-Lock Loop in the
IC synchronizes all internal timings to the AC signal at the
SYNC input.
SENS
(Pin 5)
A low level activates this input (See Table 1) which controls the
turn-on, turn-off and conduction angle, 脴 (See Figure 3), of the
TRIG signal with respect to the SYNC input.
EXT
(Pin 6)
The EXT input is functionally identical to the SENS input except
that a high level activates this input. It is recommended that the
EXT input be used instead of the SENS input when long exten-
sion wires are employed between the IC and the Sensing Cir-
cuitry (See Figure 5 and Figure 6) because the EXT input is
less susceptible to noise.
2.
INPUT/OUTPUT DESCRIPTION:
V
SS
(Pin 1)
Supply voltage positive terminal.
MODE
(Pin 2)
The LS7232ND can operate in either of 3 modes, Mode 0,
Mode 1 or Mode 2. A full description of the operating modes is
provided in Table 1. The MODE input level selects the operating
mode as follows:
7232ND-012703-1
1
2
3
4
5
