TOUCH CONTROL LAMP DIMMER
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°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.
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.
2. 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.
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:
LSI
1
2
3
4
8
7
6
5
TRIG
V
DD
(-V)
EXT
S E N S
V
SS
(+V)
MODE
CAP
SYNC
LS7232ND
FIGURE 1
PIN ASSIGNMENT - TOP VIEW
MODE Input Mode Functional Equivalent*
V
DD
0 LS7231
Vss 1 LS7232
Float 2 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 0.047µF 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, Ø (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.
7232ND-012703-1
January 2003
FEATURES:
· Phase-lock loop synchronization
allows use in Wall Switch applications.
· Provides brightness control of incandescent lamps
with touch plates or pushbutton 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.
· +12V to +18V Power Supply voltage (V
SS
- V
DD
).
· LS7232ND (DIP); LS7232ND-S (SOIC ) - See Figure 1
LSI/CSI
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631) 271-0400 FAX (631) 271-0405
LS7232ND
UL
®
A3800
TABLE 1
TOUCH TYPE
SHORT (T
S1
Duration) LONG (T
S2
Duration)
PRE-TOUCH POST-TOUCH PRE-TOUCH POST-TOUCH
Ø Ø Ø Ø
Off Max Off Starts varying at Min
Max Off Max Starts varying at Max
Intermediate Off Intermediate Starts varying at
Pre-Touch brightness
Off Memory Off Starts varying at
(Note 1) Memory (Note 2)
Max Off Max Starts varying at Max
Intermediate Off Intermediate Starts varying at
Pre-Touch brightness
Off Max Off Starts varying at Min
Max Off Max Starts varying at Max
Intermediate Off Intermediate Starts varying at
Pre-Touch brightness
V
DD
(Pin 7)
Supply voltage negative terminal.
TRIG (Pin 8)
The TRIG output is a low level pulse occurring once every half-
cycle of the SYNC input. The conduction angle, Ø, of the output
in relation to the SYNC signal controls the lamp brightness.
In continuous dimming operation (i.e. when the SENS input is
continuously held low) the TRIG conduction angle, Ø, sweeps up
and down between 41° and 158° continuously. The time vs Ø
curve is not linear (See Figure 4). Between two maxima on this
curve, there are 4 discontinuous points labeled A1, B1, B2, A2.
The discontinuities are as follows:
1. From maximum to A1. In this region, Ø is changed by
equal increments (
ø) for every 2 SYNC clocks.
2. From A1 to B1. In this region, the increments (
ø) take
place for every 4 SYNC clocks.
3. From B1 to B2. In this region Ø is held at a constant
level (
ø = 0).
4. From B2 to A2. Same as 2.
5. From A2 to Max. Same as 1.
The slower rate of change in ø over A1B1B2A2 region is to
accommodate for eye adjustment at lower light intensity.
The functional differences of the modes of the LS7232ND are explained
in Table 1 and the TRIG output conduction angle diagrams in Figure 4.
MODE
0
(LS7231)
1
(LS7232)
2
(LS7233)
DIMMING
DIRECTION
REVERSAL
(Note 3)
N/A
N/A
NO
YES
N/A
YES
N/A
N/A
YES
NOTE 1: "Memory" refers to the conduction angle, Ø, which existed prior to the current off-state.
First time after power-up, the Memory value defaults to maximum conduction angle.
NOTE 2: First time after power-up, LONG touch causes intensity to vary starting at minimum conduction angle.
NOTE 3: NO = Dimming direction does not reverse from prior dimming direction.
YES = Dimming direction does reverse from prior dimming direction.
N/A = Does not apply
7232ND-012703-2
OUTPUT
DRIVER
DIGITAL
COMPARATOR
Ø
MEMORY
Ø
POINTER
PHASE
LOCK
LOOP
CONTROL
LOGIC
BUF
BUF
BUF
SYNC
CAP
MODE
EXT
SENS
V
SS
V
DD
FIGURE 2
LS7232ND BLOCK DIAGRAM
4
3
2
6
5
1
7
TRIG
(+V)
(-V)
8
ABSOLUTE MAXIMUM RATINGS:
PARAMETER SYMBOL VALUE UNIT
DC Supply Voltage
V
SS
+20
V
Any Input Voltage
V
IN
Vss - 20 to Vss + 0.5
V
Operating Temperature
T
A
0 to +80
°C
Storage Temperature
T
STG
-65 to +150
°C
DC ELECTRICAL CHARACTERISTICS: (T
A
= 25°C, all voltages referenced to V
DD
)
PARAMETER SYMBOL
MIN
TYP MAX UNIT CONDITION
Supply Voltage Vss
+12
+18
V -
Supply Current
Iss
1.0
1.4
mA Vss = +15V,
output off
Input Voltages:
SYNC Lo
V
IRL
0
Vss - 9.5
V -
SYNC Hi
V
IRH
Vss - 5.5
Vss
V -
SENS Lo
V
IOL
0
Vss - 8
V -
SENS Hi
V
IOH
Vss - 2
Vss
V -
EXT Lo
V
IVL
0
Vss - 8
V -
EXT Hi
V
IVH
Vss - 2
Vss
V -
Input Current:
SYNC, SENS, EXT Hi
I
IH
110
µA With Series 1.5M
Resistor to AC Line
SYNC, SENS, EXT Lo
I
IL
100
nA -
TRIG Hi Voltage
V
OH
Vss
V -
TRIG Lo Voltage
V
OL
Vss - 8
V Vss = +15V
TRIG Sink Current
I
OS
25
mA Vss = +15V
V
OL
= Vss - 4V
TIMING CHARACTERISTICS (See Figures 2 and 3):
All timings are based on fs = 60Hz, unless otherwise specified. 50Hz timings are 1.2 times 60Hz timings.
PARAMETER
SYMBOL
MIN TYP MAX
UNIT
SYNC Frequency
fs
40
-
70
Hz
SHORT TOUCH
T
S1
42
-
333
ms
(ON/OFF Operation)
LONG TOUCH
T
S2
342
-
infinite
ms
(Dimming Operation)
TRIG Pulse Width
T
W
-
33
-
µs
TRIG Conduction-Angle
Ø
41
-
158 deg
(See Note 1)
Ø Period (Max to Max in
-
-
7.64
-
sec
continuous dimming)
A1B1 = B2A2 duration
-
-
934
-
ms
B1B2 Min. intensity dwell
-
-
500
-
ms
ø
TRIG
S Y N C
T
W
T
W
FIGURE 3. TRIG OUTPUT CONDUCTION ANGLE, Ø
NOTE 1.
In the circuit schematic shown in Figure 5, the SYNC input signal is delayed in phase with respect to the AC Line by about 7°. This
delay reduces the conduction angle, Ø, with respect to the AC Line by 7° from the values shown above.
7232ND-012703-3
P
1 1 5 V A C
OR
2 2 0 V A C
N
LOAD
C1
T
L
C2
R1
R2
A
B
R8
R3
C5
D1
1
2
3
4
8
7
6
5
R4
C3
C4
TRIG V
DD
EXT S E N S
V
SS
MODE CAP SYNC
+
SEE NOTE 4
L S 7 2 3 2 N D
R6
R5
SEE NOTE 3
FIGURE 5. A Typical Lamp Dimmer
G
Z
-
ELECTRONIC
EXTENSION
(FIG. 6)
EXTN
P
C7
SEE NOTE 5
SEE NOTE 2
R7
C6
N O T E S
1) All circuits connected by broken lines are optional.
2) C7 is used only with electronic extension and R7 is used only with mechanical switch.
3) See I/O Description for MODE (Pin 2)
4) Use Connection A when Neutral is not available. Use Connection B when Neutral is available.
5) Connection between Pin 6 & Pin 7 should be broken when EXT is used.
TOUCH
P L A T E
MT2
MT1
APPLICATION EXAMPLE:
A typical implementation of a lamp dimmer circuit is shown
in Fig. 5. Here the brightness of the lamp is set by touching
the Touch Plate. The functions of different components are
as follows:
·
The 15V DC supply for the chip is provided by Z, D1,
R1, C2 and C5.
·
R2 and C4 generate the filtered signal for the SYNC
input for synchronizing the internal PLL with the line
frequency.
·
R3 and C7 act as a filter circuit for the electronic
extension. If extensions are not used, the EXT input
(Pin 6) should be tied to V
DD
(Pin 7).
·
R4, R5, R6 set up the sensitivity of the SENS input.
C6 provides noise filtering.
·
C3 is the filter capacitor for the internal PLL.
·
R8 provides current limiting and isolation between the
chip output and the triac gate.
·
C1 and L are RF filter circuits.
In the case of momentary power failure, the circuit state
remains unchanged for a period of up to 1 sec. For longer
power interruptions, the output is shut off.
C1 = 0.15µF, 200V
R4 = 1M
to 5M
, 1/4W
C2 = 0.33µF, 200V
(Select for sensitivity)
C3 = 0.047µF, 25V
R5, R6 = 2.7M
, 1/4W
C4 = 470pF, 25V
R7 = 150k
, 1/4W
C5 = 47µF, 25V
R8 = 100
, 1/4W
C6 = 680pF, 25V
D1 = IN4148
C7 = 0.1µF, 25V
Z = 15V, 1W (Zener)
R1 = 270
, 1W
T = Q4006L4 Triac (Typical)
R2 = 1.5M
, 1/4W
L = 100µH (RFI Filter)
R3 = 1.5M
, 1/4W
(1) For Connection A. Use 0.22µF for Connection B.
(2) For Connection A. Use 1/4W for Connection B.
C1 = 0.15µF, 400V
R4 = 1M
to 5M
, 1/4W
C2 = 0.22µF, 400V
(Select for sensitivity)
C3 = 0.047µF, 25V
R5, R6 = 4.7M
, 1/4W
C4 = 470pF, 25V
R7 = 150k
, 1/4W
C5 = 47µF, 25V
R8 = 100
, 1/4W
C6 = 680pF, 25V
D1 = 1N4148
C7 = 0.1µF, 25V
Z = 15V, 1W (Zener)
R1 = 1k
, 2W
T = Q5004L4 Triac (Typical)
R2 = 1.5M
, 1/4W
L = 200µH (RFI Filter)
R3 = 1.5M
, 1/4W
(3) For Connection A. Use 0.1µF for Connection B.
(4) For Connection A. Use 1/4W for Connection B
.
(1)
115V
220V
(2)
(3)
(4)
EXTN
2K
,1/4W
IN914
TOUCH PLATE
*R
200K
,1/4W
MPS8599
FIGURE 6. ELECTRONIC EXTENSION
*R
P
*R = 2M
,1/4W for 115VAC
*R = 3.6M
,1/4W for 220VAC
EXTENSIONS:
All switching and dimming functions can be implemented by utilizing the
EXT input. This can be done by either a pushbutton switch or the elec-
tronic switch in conjunction with a Touch Plate, shown in Figure 6.
When the plate is touched, a logic high level is generated at the EXT
input of the IC for both half- cycles of the line frequency. (See Figure 5)
7232ND-012703-4
7232ND-012703-5
C1 = 0.15µF, 200V
C1 = 0.15µF, 400V
C2 = 0.22µF, 200V
C2 = 0.1µF, 400V
C3 = 0.047µF, 25V
C3 = 0.047µF, 25V
C4 = 470pF, 25V
C4 = 470pF, 25V
C5 = 47µF, 25V
C5 = 47µF, 25V
R1 = 270
, 1/4W
R1 = 1k
, 1/4W
R2 = 1.5M
, 1/4W
R2 = 1.5M
, 1/4W
R3 = 100
, 1/4W
R3 = 100
, 1/4W
R4 = 1M
, 1/4W
R4 = 1M
, 1/4W
D1 = IN4148
D1 = IN4148
Z1 = 15V, 1W (Zener)
Z1 = 15V, 1W (Zener)
T1 = Q4008L4 (Typical)
T1 = Q5004L4 (Typical)
L = 100µH (RFI Filter)
L = 200µH (RFI Filter)
115V
220V
APPLICATIONS:
1. Foot-Switch Dimmer for large floor lamps.
2. Hand-Switch Dimmer for end-table lamps.
1 1 5 V A C
OR
2 2 0 V A C
C1
T1
L
C2
R1
R2
R3
C5
D1
1
2
3
4
8
7
6
5
C3
C4
TRIG V
DD
EXT S E N S
V
SS
MODE CAP SYNC
+
L S 7 2 3 2 N D
G
MT2
MT1
Z1
-
R4
OUT
TO
LAMP
AC ON-OFF SWITCH
P U S H B U T T O N
SWITCH
FIGURE 7. A SWITCH-OPERATED LAMP DIMMER
(SEE NOTE 1
)
NOTE 1: Operation is independent of Line Plug Polarity
NOTE 2: See I/O Description for MODE (Pin 2)
(SEE NOTE 2)
The information included herein is believed to be
accurate and reliable. However, LSI Computer Systems,
Inc. assumes no responsibilities for inaccuracies, nor for
any infringements of patent rights of others which may
result from its use.
PDF 
ZIP