LS7538 Datasheet PDF - LSI Computer Systems

www.Datasheet-PDF.com

LS7538
LSI Computer Systems

Part Number LS7538
Description TOUCH CONTROL STEP DIMMER LIGHT SWITCH WITH AUTOMATIC GAIN CONTROL (AGC)
Page 4 Pages


LS7538 datasheet pdf
Download PDF
LS7538 pdf
View PDF for Mobile

No Preview Available !

LSI/CSI
LS7538-LS7539
U
®
L
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631) 271-0400 FAX (631) 271-0405
A3800
TOUCH CONTROL STEP DIMMER LIGHT SWITCH
WITH AUTOMATIC GAIN CONTROL (AGC)
December 2002
FEATURES:
• Touch Sensitivity guaranteed to 600pF Touch Plate Capacitance.
• Touch Operation independent of line plug polarity.
• Pin selection of three available Brightness Step Sequences.
• Minimal external components.
• AGC Loop stabilizes immediately after Power-Up.
• Brightness state is Off after AC power applied.
• Brightness state is unchanged if AC power interrupted for < 0.5 sec.
• Advanced CMOS design for reliable operating characteristics and low power.
• 50/60 Hz Line Frequency.
• +6V to +9.5V Operation (VDD-VSS).
• LS7538, LS7539 (DIP); LS7538-S, LS7539-S (SOIC) - See Figure 1
APPLICATIONS:
• Screw-in and built-in adapter modules for converting table and floor lamps
to touch control for step dimming.
• On-Off touch control of under-cabinet fluorescent lamps (LS7539 only).
PIN ASSIGNMENT
TOP VIEW
CLOCK 1
SYNC 2
)V DD(+V
3
TOUCH 4
8 TRIG
7 V SS(-V)
6 MODE
5 CONTROL
FIGURE 1
DESCRIPTION:
The LS7538 and LS7539 are CMOS integrated circuits which provide trigger pulses for triac phase control of incandescent lamps.
The circuits are designed to operate with a wide variety of lamp sizes ranging from small table lamps to large floor lamps.
The AGC Loop automatically adjusts Touch Sensitivity to be independent of lamp size.
There are 3 different Brightness Step Sequences for each version of the IC which can be selected by the Three-State
MODE pin as shown in Table 1.
TABLE 1. BRIGHTNESS STEP MODES
MODE PIN
BRIGHTNESS STEP SEQUENCE
FLOAT
OFF-NIGHT LIGHT-MEDIUM-MAXIMUM-OFF
VDD OFF-NIGHT LIGHT- LOW MEDIUM-HIGH MEDIUM-MAXIMUM-OFF
Vss (LS7538)
(LS7539)
OFF-MAXIMUM-MEDIUM-NIGHT LIGHT-OFF
OFF-MAXIMUM-OFF
The lamp brightness is made to vary by changing the delay of the TRIG pulse to the triac from the zero-crossing of the
SYNC input. The delays are shown in Table 2 for 50Hz and 60Hz operation along with Delivered Power as a percentage
of Full Power. Figure 2 illustrates the delay.
TABLE 2. BRIGHTNESS POWER LEVELS
Brightness
Night Light
Low Medium
Medium
High Medium
Maximum
60Hz Delay (1)
6.0 ms
4.8 ms
4.0 ms
3.2 ms
0.85 ms
50Hz Delay (2)
7.2 ms
5.7 ms
4.8 ms
3.8 ms
1.0 ms
% PWR (3)
12
35
53
72
99
(1) With 300kconnected between Pin 1 and VDD.
(2) With 360kconnected between Pin 1 and VDD.
(3) Percentage of Full Power delivered to a resistive load by the Triac Switch.
7538/39-120202-1



No Preview Available !

FIGURE 2. OUTPUT DELAY (Td)
SYNC (Pin 2)
TRIG(Pin 8)
Td Td
INPUT/OUTPUT DESCRIPTION:
CLOCK Input (Pin 1)
An external resistor connected between this input and
VDD, along with an internal capacitor and oscillator stage,
generates a clock which is used for all timing functions.
The recommended value of this resistor for 50Hz and
60Hz operation is specified in the ELECTRICAL CHAR-
ACTERISTICS. The resistor value determines the Bright-
ness Levels produced. (See Table 2)
SYNC Input (Pin 2)
50 or 60Hz AC input for zero crossing detection.
VDD (Pin 3)
Supply voltage positive terminal.
TOUCH Input (Pin 4)
Input for sensing that a touch has been made on a lamp
surface or other touch plate.
CONTROL I/O (Pin 5)
An external R-C network connected between this pin
and VDD establishes the controlling feedback for the
AGC Loop.
MODE Input (Pin 6)
A three-state input used to select the desired Bright-
ness Step Sequence (See Table 1). The MODE Input
may be changed during operation.
VSS (Pin 7)
Supply voltage negative terminal.
TRIG (Pin 8)
The TRIG output produces a negative going pulse eve-
ry half-cycle of the SYNC input to trigger the triac. The
delay, Td, of the pulse with respect to the SYNC signal
determines the Brightness Level produced.
(See Table 2 & Figure 2)
ABSOLUTE MAXIMUM RATINGS:
PARAMETER
DC supply voltage
Any input voltage
Operating temperature
Storage temperature
SYMBOL
VDD - VSS
VIN
TA
TSTG
VALUE
+11
VSS - 0.5 to VDD + 0.5
-20 to +85
-65 to +150
UNIT
V
V
°C
°C
7538/39-041597-2
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.



No Preview Available !

ELECTRICAL CHARACTERISTICS:
( All voltages referenced to Vss. TA = +25˚C unless otherwise specified.)
PARAMETER
Supply Voltage
Supply Current
SYMBOL
VDD
IDD
MIN
+6
-
TYP
-
-
MAX
+9.5
1.5
TRIG Sink Current
Vo = VDD - V
TRIG Source Current
Vo = VDD - 0.2V
TRIG Pulse Width
TRIG Pulse Delay
(Medium Brightness)
CLOCK Resistor
CONTROL Resistor
Capacitor
Touch Plate Capacitance
IO
IO
TW
-
Td
RC
-
-
-
CL
-50
+0.1
-
-
-
-
-
-
-
-
-
-
-
90
110
4.0
4.8
300
360
10
1
-
-
-
-
-
-
-
-
-
-
-
600
UNIT
V
mA
mA
CONDITIONS
-
Output off,
VDD = +8.0V
VDD = +8.0V
mA VDD = +8.0V
µs RC = 300k, 60Hz
µs RC = 360k, 50Hz
ms Rc = 300k, 60Hz
ms Rc = 360k, 50Hz
k60Hz
k50Hz
M-
µF -
pF -
MODE 6
SYNC 2
ZERO-CROSS
DETECTOR
CLOCK 1
OSCILLATOR
COUNTER
DECODER
OUTPUT
DRIVER
8 TRIG
TOUCH 4
AGC CIRCUIT
STEPPER
CONTROL 5
V DD 3
V SS 7
+V
-V
FIGURE 3
LS7538/LS7539 BLOCK DIAGRAM
7538/39-041197-3



No Preview Available !

FIGURE 4. TOUCH LAMP APPLICATION SCHEMATIC
AC
MAINS
R1 D1
Z1
+V
+
C1
-
MT2
MT1
LOAD
T1
G
R5 +
- C6
-V
C2
R2
TOUCH
PLATE
(LAMP BODY)
C5 (SEE NOTE 1)
87
6
5
TRIG V SS MODE CONT
LS7538
CLOCK SYNC V DD TOUCH
1
23
4
D2 D3
R4
C3 C4
R3
C7* (SEE NOTE 2)
R1 =
R2 =
R3 =
(1) R4 =
R5 =
C1 =
C2 =
C3 =
115VAC APPLICATION
220VAC APPLICATION
20k, 1W
470k, 1/4W
1k, 1/4W
300k, 1/4W, 1%
10M, 1/4W
47µF, 16V
1000pF, 16V
1000pF, 1kV
C4 = 1000pF, 1kV
C5 = .03µF, 16V
C6 = 1µF, 16V
Z1 = 8.2V, 1/4W Zener
D1 = 1N4004
D2 = 1N4148
D3 = 1N4148
T1 = Q2004L4 (Typical Triac)
or Q2004F41 (Typical Triac)
R1 =
R2 =
(1) R4 =
D1 =
T1 =
or
39k, 2W
910k, 1/4W
360k, 1/4W, 1%
1N4005
Q4004L4 (Typical Triac)
Q4004F41 (Typical Triac)
All other values remain the same.
(1) Resistor should be placed adjacent to Pin 1.
NOTE 1: Connect MODE (Pin 6) for desired Brightness Step Sequence (See Table 1).
NOTE 2: A good PCB layout using through-hole components will provide protection for ESD introduced at the Touch Plate in the range
of 25kV. Using surface mount components and/or a poor PCB layout can reduce the ESD protection. The OEM can increase the ESD
protection provided by the product with any combination of the following steps:
Step 1: The most effective and least costly way to increase ESD protection is to create a spark gap around the Touch Plate input on
the PCB. This will increase ESD protection on a good PCB layout to abut 35kV. The gap should be made with a split metal ring with
each side of the metal ring connected back to opposite sides of the AC line. This ensures that a path for the spark back to house ground
through AC Neutral exists independent of line plug polarity. The split ring and the center conduction plate should be constructed so that
the spacing between them conforms to UL requirements. The spark gap will absorb most of the ESD leaving a remnant of about 10kV
for the rest of the circuit to absorb.
Step 2: Increase R3 from 1kto 5.1kand add C7, a 0.1µF capacitor, between VDD and Vss.
(A minimal loss in touch sensitivity may be experienced.)
Step 3: Replace diodes D2 and D3 (1N4148) with Schottky diodes (1N5819 or similar)
7538/39-091100-4



LS7538 datasheet pdf
Download PDF
LS7538 pdf
View PDF for Mobile


Related : Start with LS753 Part Numbers by
LS7534 DIMMER LIGHT SWITCH WITH UP AND DOWN CONTROLS LS7534
LSI Computer Systems
LS7534 pdf
LS7535 DIMMER LIGHT SWITCH WITH UP AND DOWN CONTROLS LS7535
LSI Computer Systems
LS7535 pdf
LS7538 TOUCH CONTROL STEP DIMMER LIGHT SWITCH WITH AUTOMATIC GAIN CONTROL (AGC) LS7538
LSI Computer Systems
LS7538 pdf
LS7539 TOUCH CONTROL STEP DIMMER LIGHT SWITCH WITH AUTOMATIC GAIN CONTROL (AGC) LS7539
LSI Computer Systems
LS7539 pdf

Index :   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z   

This is a individually operated, non profit site. If this site is good enough to show, please introduce this site to others.
Since 2010   ::   HOME   ::   Contact