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LS7631 参数 Datasheet PDF下载

LS7631图片预览
型号: LS7631
PDF下载: 下载PDF文件 查看货源
内容描述: 触摸控制卤素灯的调光 [TOUCH CONTROL HALOGEN LAMP DIMMER]
分类和应用: 卤素灯
文件页数/大小: 4 页 / 48 K
品牌: LSI [ LSI COMPUTER SYSTEMS ]
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LSI/CSI
UL
®
LS7631/7632
(631) 271-0400 FAX (631) 271-0405
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
A3800
TOUCH CONTROL HALOGEN LAMP DIMMER
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 (V
DD
- V
SS
)
• LS7631, LS7632 (DIP); LS7631-S, LS7632-S (SOIC)
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 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 (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.
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 safety-
shutdown 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 safety-
shut-down is effected.
PIN ASSIGNMENT - TOP VIEW
V
DD
(+V)
1
8
TRIG
November 2002
LSI
MODE
2
7
V
SS
(-V)
LS7631
LS7632
CAP
3
6
EXT
SYNC
4
5
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
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 6.
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.
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.
7631/7632-112002-1