UL
®
LSI/CSI
LS7634 LS7635
LS7634FO LS7635FO
(631) 271-0400 FAX (631) 271-0405
October 2008
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
A3800
TOUCH CONTROL HALOGEN LAMP DIMMER
FEATURES:
• Touch or pushbutton control of high-voltage lamps
and
*transformer-coupled
low-voltage halogen lamps
*Magnetic Transformers and most Electronic Transformers
• Automatic Safety Shutdown
• Three operating modes
• Extension input for remote activation
• 50Hz/60Hz AC line frequency
• +5V Power Supply (V
DD
-V
SS
)
• LS7634, LS7635 (DIP); LS7634-S, LS7635-S (SOIC);
LS7634FO, LS7635FO (DIP);
LS7634FO-S, LS7635FO-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 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 LS7634/LS7635
family of CMOS ICs as follows:
1. 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. Delayed triac turn-on and safety shutdown
With inductive loads, the holding current needed to maintain
the triac On-State, may seriously lag behind the gate trigger
signal causing the triac to turn off prematurely. 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
LSI
V
DD
(+V )
MODE
TEST
SYNC
1
2
3
4
8
7
6
5
TRIG
V
SS
(-V )
EXT
SENS
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
All variations of LS7634 and LS7635 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
SYNC
(Pin 4) - See Figure 6
The AC line frequency is applied to this input. All internal timings
are synchronized to the AC. 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.
Test
(Pin 3)
LS7634
LS7635
For factory use only.
7634/7635-102708-1
The differences among all versions of LS7634 and LS7635 are:
LS7634 (LS7634FO)
Upon power-up, the TRIG output is Off.
(Upon power-up, the TRIG output is On at maximum conduction angle.)
When a LONG touch is applied, the dimming direction automatically re-
verses whenever maximum or minimum conduction angles are reached.
LS7635 (LS7635FO)
Upon power-up, the TRIG output is Off.
(Upon power-up, the TRIG output is On at maximum conduction angle.)
When a LONG touch is applied, the dimming stops whenever 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
LS7635 NOTE:
If the User applies a LONG Touch when the TRIG Conduc-
tion Angle is within a “few” degrees of Maximum or Mini-
mum, the TRIG Conduction Angle can move to Maximum or
Minimum and stop without the User being able to observe a
change in brightness. There-fore, the User should be in-
structed that if no change in brightness is observed in re-
sponse to a LONG Touch, the LONG Touch should be re
moved and reapplied in order to produce a change in bright-
ness.
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
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
OFF
ON
MAX (Note 1)
OFF
A soft turn-on is produced by slewing up the conduction angle, ø, from minimum at the rate of 1.4
˚
/8.33ms (60Hz).
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
- Vss
V
IN
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
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
7634/7635-010906-2
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 (see Note 5)
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
-
-
50
-
-
-
-
-
-
-
-
-
TYP
-
-
-
-
-
130
156
-
1.4
1.4
1.4
1.4
1.4
1.4
1.4
500
600
MAX
70
333
400
infinite
infinite
-
-
154
-
-
-
-
-
-
-
-
-
UNI T
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 number of steps = 77.
Number of steps from A0 to A1, or A2 to A0 = 55.
Number of steps from A1 to B1 or B2 to A2 = 21.
ø is at minimum between B1 and B2. T
BD
is applicable for LS7634 only.
For LS7635 when minimum ø is reached, dimming direction reverses only if the
LONG
Touch is terminated and reapplied.
Note 5:
T
W
= 488us (60Hz), 586us (50Hz) available. Contact factory for details.
FIGURE 2. TRIG OUTPUT CONDUCTION ANGLE, Ø
SYNC
ø
TRIG
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.
T
W
FIGURE 3. LS7634 TRIG, Ø vs TOUCH (SENS OR EXT)
T
S1
SENS
SHORT
SHORT
LONG
A0
150º
T
S2
SHORT
LONG
SHORT
LONG
Ø
MODE Ø
100º
50º
OFF
342ms
A2
B2
SLOPE = S
BA
SLOPES = S
AA
A1
B1 B2
A0
A2
SLOPE = Ss
A0
MEMORY
150º
Ø
MODE 1
100º
50º
OFF
A1
B1
B2
A2
REVERSE
A0
150º
Ø
MODE 2
100º
50º
OFF
B2
A2
A1
B1 B2
A2
REVERSE
7634/7635-071406-3
FIGURE 4. LS7635 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
B2
A1
B1
B2
A2
B2
A2
MEMORY
MEMORY
Ø
MODE 1
150º
100º
50º
OFF
A1
B1 B2
A2
REVERSE
A1
A2
B1
B2
REVERSE
150º
100º
50º
OFF
B2
Ø
MODE 2
A0
A0
A0
A0
A2
B2
A2
FIGURE 5. A Typical Halogen Lamp Dimmer Wall Switch
P
**C6
MT1
G
P
SEE NOTE 2
R8
C5
R3
R7
EXTN
ELECTRONIC
EXTENSION
(FIG. 7)
**R9
MT2
T
Z
+
C4
R5
-
SEE NOTE 3
TOUCH
PLATE
NOTES
R6
115VAC
OR
220VAC
L
C1
C2
R1
V
DD
D1
8
TRIG
7
V
SS
6
EXT
5
SENS
LS7634 / LS7635
MODE TEST SYNC
R2
1
2
3
4
R4
SEE
NOTE 4
LAMP
C3
N
1.
All circuits connected by broken lines are optional.
2.
C5 is used only with electronic extension
and R7 is used only with mechanical switch.
3.
Connection between Pin 6 & Pin 7 should
be broken when EXT is used.
4.
Magnetic transformer should have thermal protection.
5.
Some electronic transformers may require larger
values of C2, sensitive gate triacs and snubber
networks. C2 values may have to be adjusted to be as
high as 0.47uF for 115VAC and 0.33uF for 220VAC.
The sensitive gate triacs are chosen for their low
holding current. Typical triacs are L4004L6 and L6004L6
for 115VAC and 220VAC applications, respectively.
**C6-R9 is the snubber network: C6 = 0.1uF, 200V,
R9 = 1k Ohm, 1/2W (115VAC); C6 = 0.05uF, 400V,
R9 = 1k Ohm, 1W (220VAC)
C1 = 0.15µF, 200V
*
C1 = 0.15µF, 400V
C2 = 0.22µF, 200V
*
C2 = 0.15µF, 400V
C3 = 0.002µF, 10V
*
Component change for 220VAC
**
Snubber Network (See Note 5)
FIGURE 6.
C4 = 100µF, 10V
C5 = 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
Z = 5.6V, 1W (Zener)
T = Q4004L4 Typical Triac
(1)
*
T = Q5003L4 Typical Triac
(1)
L = 100µH (RFI Filter)
*
L = 200µH (RFI Filter)
(1)
For loads greater than 6A,
use an alternistor
ELECTRONIC EXTENSION
MPS8599
EXT
10kΩ
TOUCH PLATE
200kΩ
*R
= 2M
Ω
for 115VAC
*R
= 3.6M
Ω
for 220VAC
All Resistors 1/4W
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 C4.
• R2 and C3 generate the filtered signal for the SYNC input
AC phase synchronization.
• R3 and C5 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.
• R8 provides current limiting and isolation between the chip
output and the triac gate.
• C1 and L are RFI filter circuits.
P
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)
7634/7635-090606-4
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