LSI LS7631

LSI/CSI
UL
®
LS7631/7632
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
(631) 271-0400 FAX (631) 271-0405
A3800
TOUCH CONTROL HALOGEN LAMP DIMMER
BACKGROUND AND GENERAL DESCRIPTION:
A typical electronic dimmer may not operate properly with the inductive 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 alternate half-cycles only, which may lead to the thermal destruction of the load transformer. The problems encountered in
driving an inductive load are addressed by the LS7631/LS7632
CMOS ICs as follows:
V DD (+V)
1
MODE
2
CAP
3
SYNC
4
LS7631
LS7632
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.
PIN ASSIGNMENT - TOP VIEW
LSI
FEATURES:
• Touch or pushbutton control of incandescent lamps
and transformer-coupled halogen lamps
• Transformer can be Magnetic or Electronic
• Direct replacement for P/N SLB 0587
• 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 Power Supply (VDD - VSS)
• LS7631, LS7632 (DIP); LS7631-S, LS7632-S (SOIC)
November 2002
8
TRIG
7
V SS (-V)
6
EXT
5
SENS
FIGURE 1
INPUT/OUTPUT DESCRIPTION:
VDD (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; VDD = Mode 2
CAP (Pin 3) - PLL filter capacitor input. See Figure 6.
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 (60 Hz) 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.
SYNC (Pin 4) - See Figure 6
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.
3. Safety-shutdown.
If the frequency of occurrences of the delayed cut-off and
delayed turn-on exceeds a preset threshold, a shutdown is
initiated by turning off the triac trigger pulses. The safetyshutdown threshold value is accumulated in a 4-bit Up/Down
counter. The count increments for every occurrence of
delayed cut-off or 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 safetyshut-down is effected.
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.
7631/7632-112002-1
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.
TRIG (Pin 8)
The TRIG output is a low level pulse occurring once every halfcycle of the AC and is intended to drive the gate of a triac in series 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.
The functional differences between LS7631 and LS7632 are:
LS7631 - When a LONG touch is applied, the dimming direction automatically reverses whenever maximum or minimum conduction angles are reached.
LS7632 - 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.
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 brightness is observed in response to a LONG Touch, the
LONG Touch should be removed and reapplied in order
to produce a change in brightness.
TABLE 1
MODE
SHORT TOUCH
PRE-TOUCH Ø
0
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
POST-TOUCH Ø
PRE-TOUCH Ø
POST-TOUCH Ø
DIMMING
REVERSAL
(Note 5)
OFF
ON
MAX(Note 1)
OFF
OFF/MIN
MAX
INTERMEDIATE
Varies up from MIN
Varies down from MAX
Varies from INTERMEDIATE
N/A
N/A
NO
OFF
ON
MEMORY
(Notes 2, 3)
OFF
OFF
MIN
MAX
INTERMEDIATE
Varies from memory (Notes 2, 3,4)
Varies up from MIN
Varies down from MAX
Varies from INTERMEDIATE
YES
N/A
N/A
YES
OFF
ON
MAX (Note 1)
OFF
OFF/MIN
MAX
INTERMEDIATE
Varies up from MIN
Varies down from MAX
Varies from INTERMEDIATE
N/A
N/A
YES
1
2
LONG TOUCH
A soft turn-on is produced by slewing up the conduction angle, ø, from minimum at the rate of 1.4˚/4.17ms (60Hz).
There are a total of 84 discrete values 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
SYMBOL
VALUE
UNIT
DC supply voltage
Any input voltage
Operating temperature
Storage temperature
VDD - Vss
VIN
TA
TSTG
+7
Vss - 0.3 to VDD + 0.3
0 to +90
-65 to +150
V
V
°C
°C
DC ELECTRICAL CHARACTERISTICS:
(TA = +25˚C, all voltages referenced to Vss. VDD = +5V unless otherwise noted.)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
Supply voltage
Supply current
VDD
IDD
4.5
-
5.0
300
5.5
400
V
µA
SYNC Lo
VISL
-
-
2.1
V
SYNC Hi
VISH
2.9
-
-
V
-
EXT, SENS Lo
VIEL
-
-
1.5
V
-
EXT, SENS Hi
TRIG Lo
TRIG Hi
VIEH
VOL
VOH
3.5
-
0.2
5.0
-
V
V
V
-
TRIG Sink Current
ITSNK
35
-
-
7631/7632-111902-2
mA
CONDITION
Output unloaded
VDD = 5.5V
-
VOTRIG = 2.5V
TIMING CHARACTERISTICS (See Figures 2, 3 and 4):
PARAMETER
SYMBOL
MIN
TYP
MAX
fs
TSI
TSI
TS2
TS2
Tw
Tw
ø
∆ø
40
42
50
342
410
41
-
130.2
156.2
1.4
70
333
400
infinite
infinite
158
-
Hz
ms
ms
ms
ms
µs
µs
deg
deg
-
deg/4.17ms
deg/5ms
deg/33.3ms
deg/40ms
deg/66.7ms
deg/80ms
ms
ms
SYNC Frequency
SHORT Touch
LONG Touch
TRIG pulse width
Conduction Angle
ø incremental steps
(Note 1)
Soft-on slew rate
SS
SS
SAA
SAA
SBA
SBA
TBD
TBD
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:
-
1.4
1.4
1.4
1.4
1.4
1.4
500
600
UNIT
CONDITION
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
60Hz
50Hz
Total number 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. TBD is applicable for LS7631 only.
For LS7632 when minimum ø is reached, dimming direction reverses only if the LONG Touch is terminated and reapplied.
FIGURE 2. TRIG OUTPUT CONDUCTION ANGLE, Ø
REPLACEMENT FOR P/N SLB 0587
LS7631 and LS7632 can be used in place of the SLB 0587
without modifying the application circuit recommended by
the manufacturer of that IC.
SYNC
ø
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.
TRIG
TW
FIGURE 3. LS7631 TRIG, Ø vs TOUCH (SENS OR EXT)
TS1
TS2
SENS
SHORT
SHORT
LONG
SHORT
LONG
SHORT
A0
150º
Ø
MODE Ø
50º
OFF
SLOPE = S BA
342ms
100º
A2
SLOPES = S AA
A1
SLOPE = Ss
A2
B1 B2
MEMORY
A0
A0
150º
Ø
MODE 1
100º
50º
A1
OFF
B1
B2
REVERSE
A2
A0
150º
Ø
MODE 2
100º
50º
OFF
7631/7632-112102-3
A2
A1
A2
B1 B2
REVERSE
LONG
FIGURE 4. LS7632 TRIG, Ø vs TOUCH (SENS OR EXT)
TS1
TS2
SENS
Ø
MODE Ø
LONG
SHORT
SHORT
LONG
LONG
LONG
342ms
150º
100º
LONG
SHORT
SLOPE = S BA
A0
A0
50º
SHORT
A2
OFF
A1
SLOPE = S AA
B1
A2
B2
A2
SLOPE = S S
MEMORY
MEMORY
150º
100º
Ø
MODE 1
REVERSE
50º
A1
B1 B2
OFF
A2
A2
A1
B1
B2
A0
A0
REVERSE
150º
100º
Ø
MODE 2
A0
A0
50º
A2
A2
OFF
FIGURE 6. A Typical Halogen Lamp Dimmer Wall Switch
P
SEE NOTE 2
P
MT1
Z
R7
EXTN
R3
+
C5
T
MT2
C6
R8
G
ELECTRONIC
EXTENSION
(FIG. 7)
-
SEE NOTE 3
D1
L
115VAC
OR
220VAC
R6
C1
8
C2
7
6
5
TOUCH
PLATE
TRIG V SS EXT S E N S
LS7631/LS7632
R1
V DD MODE
R2
1
2
CAP SYNC
3
4
C3
SEE
NOTE 4
R5
LAMP
C4
R4
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 & Pin 7 should
be broken when EXT is used.
4. As a precaution, transformer should have
thermal protection.
N
C1 = 0.15µF, 200V
= 0.15µF, 400V
* C1
C2 = 0.15µF, 200V
* C2 = 0.082µF, 400V
C3 = 0.02µF, 10V
C4 = 0.002µF, 10V
* = component change for 220VAC
FIGURE 7.
C5 = 100µF, 10V
C6 = 0.1µF, 10V
R1 = 270Ω, 1/2W
* R1 = 1kΩ, 1W
R2 = 680Ω, 1/4W
= 1.5MΩ, 1/4W
* R2
R3 = 1.5MΩ, 1/4W
Z = 5.6V, 1W (Zener)
T = Q4004L4 Typical Triac (1)
* T = Q5003L4 Typical Triac (1)
L = 100µH (RFI Filter)
200µH (RFI Filter)
* L(1)= For
loads greater than 6A,
use an alternistor
.
ELECTRONIC EXTENSION
MPS8599
EXT
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
IN914
*R
*R
10kΩ
APPLICATION EXAMPLE:
A typical implementation of the light dimmer circuit is shown in Fig. 6.
Here the brightness of the lamp is set by touching the touch plate.
The function of different components are as follows:
TOUCH PLATE
200k Ω
*R = 2M Ω for 115VAC
*R = 3.6M Ω for 220VAC
All Resistors 1/4W
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 7. When the plate is touched, a logic high
level is generated at the EXT input of the IC for both halfcycles of the line frequency. (See Figure 6)
7631/32-112102-4
• 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.