UL
®
LSI/CSI
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
LSI
LS7631
LS7632
(631) 271-0400 FAX (631) 271-0405
A3800
TOUCH CONTROL HALOGEN LAMP DIMMER
FEATURES:
• Touch or pushbutton control of incandescent lamps
and
*transformer-coupled
halogen lamps.
*Magnetic
transformers and most Electronic transformers
• Direct replacement for P/N SLB0587
(See “DISCUSSION” on Page 3)
• Automatic safety shutdown
• PLL synchronization allows use as a Wall Switch
• Three operating modes
• Extension input for remote activation
• 50Hz/60Hz AC line frequency
• +5V operating voltage (V
DD
- V
SS
)
• LS7631, LS7632 (DIP); LS7631-S, LS7632-S (SOIC)
- See Figure 1 -
APPLICATIONS:
Electronic dimmers for wall switch control of ceiling mounted
lighting, foot switch control of large floor lamps and hand switch
control of table lamps.
BACKGROUND AND GENERAL DESCRIPTION:
A typical electronic dimmer may not operate properly with the in-
ductive load encountered when driving a magnetic transformer-
coupled low-voltage halogen lamp. The inductive load can cause
a phenomenon called half-waving, wherein the triac fires in al-
ternate half-cycles only, which may lead to the thermal de-
struction of the load transformer. The problems encountered in
driving an inductive load are addressed by the LS7631/LS7632
CMOS ICs as follows:
1. Compensation for delayed triac cut-off.
When a trigger pulse is due to occur at a conduction
angle which coincides with the on-state of the triac,
the trigger pulse is delayed until the triac has turned off.
This eliminates the underlying cause of half-waving.
.
2. Compensation for delayed triac turn-on.
At the set conduction angle, a triac trigger pulse of 130.2µs
(60Hz) is issued by the IC. If the triac fails to fire, a second
trigger pulse of 260.4µs width is issued 1ms later as a
second attempt to fire the triac during the same half-cycle.
3. Safety-shutdown.
If the frequency of occurrences of the delayed turn-on exceeds
a preset threshold, a shutdown is initiated by turning off the
triac trigger pulses. The safety-shutdown threshold value is
accumulated in a 4-bit Up/Down counter. The count
increments for every occurrence of delayed turn-on and
decrements once every 8 SYNC pulses (AC line cycles).
The counter will not decrement below zero. If the count
reaches 15, the safety-shut-down is effected.
PIN ASSIGNMENT - TOP VIEW
V
DD
(+V)
1
8
TRIG
V
SS
(-V)
December 2005
MODE
2
3
7
LS7631
LS7632
CAP
SYNC
6
EXT
SENS
4
5
FIGURE 1
INPUT/OUTPUT DESCRIPTION:
V
DD
(Pin 1) Supply voltage positive terminal.
Vss
(Pin 7) Supply voltage negative terminal.
MODE
(Pin 2) - See Table 1
Both LS7631 and LS7632 can operate in 3 different modes.
The 3-state MODE input selects the operating modes:
Vss = Mode 0; Float = Mode 1; V
DD
= Mode 2
CAP
(Pin 3) - PLL filter capacitor input. See Figure 5.
SYNC
(Pin 4) - See Figure 5
The AC line frequency is applied to this input. All internal timings
are synchronized to the AC phase through a PLL circuit.
The Load On/Off status information is also derived from this input.
SENS
(Pin 5) - See Table 1
A Logic 0 applied to this input alters the TRIG output either by
turning it on, turning it off or by changing its conduction angle.
Specifically which action takes place is dependent on the type of
activation of the SENS input, namely SHORT or LONG touch
and the prior state of TRIG output.
EXT
(Pin 6)
Same functionality as the SENS input, except that a Logic 1 is the
active level at this input. EXT input is intended to be operated
from a remote site with long cable connection, when noise can be
expected. The sampling method used at this input makes it less
sensitive to noise.
TRIG
(Pin 8)
The TRIG output is a low level pulse occurring once every half-
cycle of the AC and is intended to drive the gate of a triac in se-
ries with the load. The conduction angle, ø, of the TRIG pulse can
be varied by means of LONG and SHORT touches at either the
SENS or the EXT input.
7631-120505-1
The functional differences between LS7631 and LS7632 are:
LS7631
- When a LONG touch is applied, the dimming direction auto-
matically reverses whenever maximum or minimum conduction an-
gles are reached.
LS7632
- When a LONG touch is applied, the dimming stops when-
ever maximum or minimum conduction angles are reached. In order to
change dimming levels from maximum or minimum, LONG touch must
be removed and reapplied. The purpose of this feature is to allow the
user to positively locate maximum and minimum conduction angles.
TABLE 1
MODE
SHORT TOUCH
PRE-TOUCH Ø
OFF
ON
POST-TOUCH Ø
MAX(Note 1)
OFF
PRE-TOUCH Ø
OFF/MIN
MAX
INTERMEDIATE
OFF
MIN
MAX
INTERMEDIATE
OFF/MIN
MAX
INTERMEDIATE
LS7632 NOTE:
If the User applies a LONG Touch when
the TRIG Conduction Angle is within a “few” degrees of
Maximum or Minimum, the TRIG Conduction Angle can
move to Maximum or Minimum and stop without the User
being able to observe a change in brightness. Therefore,
the User should be instructed that if no change in bright-
ness is observed in response to a LONG Touch, the
LONG Touch should be removed and reapplied in order to
produce a change in brightness.
LONG TOUCH
POST-TOUCH Ø
Varies up from MIN
Varies down from MAX
Varies from INTERMEDIATE
Varies from memory (Notes 2, 3,4)
Varies up from MIN
Varies down from MAX
Varies from INTERMEDIATE
Varies up from MIN
Varies down from MAX
Varies from INTERMEDIATE
DIMMING
REVERSAL
(Note 5)
N/A
N/A
NO
YES
N/A
N/A
YES
N/A
N/A
YES
0
OFF
1
ON
MEMORY
(Notes 2, 3)
OFF
2
OFF
ON
MAX (Note 1)
OFF
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
A soft turn-on is produced by slewing up the conduction angle, ø, from minimum at the rate of 1.4
˚
/8.33ms (60Hz).
There are a total of 84 discrete steps of ø.
A soft turn-on is produced by slewing up ø, from minimum to memory.
Upon power-up the memory value is defaulted to maximum conduction angle.
“Memory” refers to the conduction angle, ø, which existed prior to the current off-state.
A soft turn-on is produced by slewing up ø from minimum to memory upon which the dimming is started.
NO
= Dimming direction does not reverse from prior dimming direction.
YES
= Dimming direction does reverse from prior dimming direction.
N/A
= Does not apply.
ABSOLUTE MAXIMUM RATINGS:
PARAMETER
DC supply voltage
Any input voltage
Operating temperature
Storage temperature
SYMBOL
V
DD
- Vs
S
V
I N
T
A
T
STG
VALUE
+7
Vss - 0.3 to V
DD
+ 0.3
0 to +90
-65 to +150
UNIT
V
V
°C
°C
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.
DC ELECTRICAL CHARACTERISTICS:
(T
A
= +25˚C, all voltages referenced to Vss. V
DD
= +5V unless otherwise noted.)
PARAMETER
Supply voltage
Supply current
SYNC
Lo
SYNC
Hi
EXT, SENS
Lo
EXT, SENS
Hi
TRIG Lo
TRIG Hi
TRIG
Sink Current
7631-120505-2
SYMBOL
V
DD
I
DD
V
ISL
V
ISH
V
IEL
V
IEH
V
OL
V
OH
I
TSNK
MIN
4.5
-
-
2.9
-
3.5
-
-
35
TYP
5.0
300
-
-
-
-
0.2
5.0
-
MAX
5.5
400
2.1
-
1.5
-
-
-
-
UNIT
V
µA
V
V
V
V
V
V
mA
CONDITION
-
Output unloaded
V
DD
= 5.5V
-
-
-
-
-
-
V
OTRIG
= 2.5V
TIMING CHARACTERISTICS
(See Figures 2, 3 and 4):
PARAMETER
SYNC
Frequency
SHORT
Touch
LONG
Touch
TRIG
pulse width
Conduction Angle
ø incremental steps
(Note 1)
Soft-on slew rate
A0 to A1/A2 to A0 slew rate
(Note 2)
A1 to B1/B2 to A2 slew rate
(Note 3)
B1 to B2 delay
(Note 4)
Note 1:
Note 2:
Note 3:
Note 4:
SYMBOL
fs
T
SI
T
SI
T
S2
T
S2
Tw
Tw
ø
∆ø
S
S
S
S
S
AA
S
AA
S
BA
S
BA
T
BD
T
BD
MIN
40
42
50
342
410
-
-
41
-
-
-
-
-
-
-
-
-
TYP
-
-
-
-
-
130.2
156.2
-
1.4
1.4
1.4
1.4
1.4
1.4
1.4
500
600
MAX
70
333
400
infinite
infinite
-
-
158
-
-
-
-
-
-
-
-
-
UNIT
Hz
ms
ms
ms
ms
µs
µs
deg
deg
deg/8.33ms
deg/10ms
deg/33.3ms
deg/40ms
deg/66.7ms
deg/80ms
ms
ms
CONDITION
-
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
-
-
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
Total nimber of steps = 83
Number of steps from A0 to A1 or A2 to A0 = 68
Number of steps from A1 to B1 or B2 to A2 =15
ø is at minimum between B1 and B2. T
BD
is applicable for LS7631 only.
For LS7632 when minimum ø is reached, dimming direction reverses only if the
LONG
Touch is terminated and reapplied.
DISCUSSION: REPLACEMENT FOR SLB0587
There are minor design differences between LS7631 and SLB0587
requiring component value changes to the external application circuitry.
•
The LS7631 SENS and EXT input switching levels differ from SLB0587.
This can require external input resistor ratios to be changed.
•
The LS7631 PLL characteristics differ from the SLB0587. In order to
achieve optimum PLL stability, LS7631 requires a 0.02uF Filter Cap
connected between Pin 3 and V
SS
while SLB0587 requires a 100nF
Filter Cap with a series 330k Ohm resistor connected between
Pin 3 and V
SS.
Adjusting the application circuit for these differences will result in LS7631
functioning the same as SLB0587.
FIGURE 3. LS7631 TRIG,
ø
vs TOUCH (SENS OR EXT)
T
S1
FIGURE 2. TRIG OUTPUT CONDUCTION ANGLE,
ø
SYNC
ø
TRIG
T
W
SENS
SHORT
SHORT
LONG
A0
150º
T
S2
SHORT
LONG
SHORT
LONG
Ø
MODE Ø
100º
50º
OFF
SLOPE = Ss
342ms
A2
SLOPES = S
AA
A1
SLOPE = S
BA
B1 B2
A0
A2
A0
150º
MEMORY
Ø
MODE 1
100º
50º
OFF
A1
B1
B2
A2
REVERSE
A0
150º
Ø
MODE 2
100º
50º
OFF
A2
A1
B1 B2
A2
REVERSE
7631-120505-3
FIGURE 4. LS7632 TRIG, Ø vs TOUCH (SENS OR EXT)
T
S1
SENS
SHORT
SHORT
LONG
LONG
LONG
LONG
SHORT
LONG
SHORT
T
S2
Ø
MODE Ø
150º
100º
50º
OFF
SLOPE = S
S
342ms
A0
A2
SLOPE = S
AA
A0
SLOPE = S
BA
A1
B1
B2
A2
A2
MEMORY
MEMORY
Ø
MODE 1
150º
100º
50º
OFF
A1
B1 B2
A2
REVERSE
A1
A2
B1
B2
REVERSE
150º
100º
50º
OFF
A2
A0
A0
A0
A0
Ø
MODE 2
A2
FIGURE 5. A Typical Halogen Lamp Dimmer Wall Switch
P
G
P
SEE NOTE 2
R8
+
T
Z
C5
C6
R7
EXTN
MT1
MT2
R3
ELECTRONIC
EXTENSION
(FIG. 6)
R6
8
7
V
SS
-
SEE NOTE 3
115VAC
OR
220VAC
L
C1
D1
6
EXT
R5
5
SENS
C2
TOUCH
PLATE
TRIG
R1
R2
1
LS7631/LS7632
V
DD
MODE CAP SYNC
2
3
C3
4
C4
R4
SEE
NOTE 4
N
LAMP
NOTES
1. All circuits connected by broken lines are optional.
2.
C6 is used only with electronic extension
and R7 is used only with a pushbutton.
3.
Connection between Pin 6 and Pin 7
should be broken when EXT is used.
4.
As a precaution, transformer
should have thermal protection.
Z = 5.6V, 1W (Zener)
T = Q4004L4 Typical Triac
= Q5003L4 Typical
*
T = 100µH (RFI Filter)Triac
L
*
L = 200µH (RFI Filter)
C1 = 0.15µF, 200V
*
C1 = 0.15µF, 400V
C2 = 0.15µF, 200V
*
C2 = 0.082µF, 400V
C3 = 0.02µF, 10V
C4 = 0.002µF, 10V
FIGURE 6.
EXT
10k
C5 = 100µF, 10V
C6 = 0.1µF, 10V
R1 = 270Ω, 1/2W
*
R1 = 1kΩ, 1W
R2 = 680kΩ, 1/4W
*
R2 = 1.5MΩ, 1/4W
R3 = 1.5MΩ, 1/4W
R4 = 1MΩ to 5MΩ, 1/4W
(Select for Sensitivity)
R5, R6 = 2.7MΩ, 1/4W
*
R5, R6 = 4.7MΩ, 1/4W
R7 = 150kΩ, 1/4W
R8 = 62Ω, 1/4W
D1 = 1N4148
*
= Component change for 220VAC
.
ELECTRONIC EXTENSION
MPS8599
IN914
*R
*R
APPLICATION EXAMPLE:
A typical implementation of the light dimmer circuit is shown in Fig. 5.
Here the brightness of the lamp is set by touching the touch plate.
The function of different components are as follows:
• The 5V 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 C6 act as a filter circuit for the electronic extension.
If extensions are not used, the EXT input (Pin 6) should be
tied to Vss (Pin 7).
• R4, R5 and R6 set up the sensitivity of the SENS input.
• 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 RFI filter circuits.
TOUCH PLATE
*R
= 2M
Ω
for 115VAC
*R
= 3.6M
Ω
for 220VAC
All Resistors 1/4W
P
200k
EXTENSIONS:
All switching and dimming functions can be
implemented by utilizing the EXT input. Use a pushbutton or
the electronic switch in conjunction with a Touch Plate as
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)
7631-120505-4
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