LS7232NT - LSI csi

LSI/CSI
UL
®
LS7232NT
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
(631) 271-0400 FAX (631) 271-0405
A3800
PROXIMITY/TOUCH CONTROL HALOGEN LAMP DIMMER
FEATURES:
• Control of incandescent and transformer-coupled
low voltage halogen lamps.
• No-Touch lamp control through optical sensing
• PLL synchronization of AC for wall switch application.
• Extension input for remote control
• Safety-shutdown for transformer malfunction.
• Pin-selectable operating modes
• Single 5V power supply
• 50Hz/60Hz AC line frequency
• LS7232NT (DIP); LS7232NT-S (SOIC) - See Figure 1
DESCRIPTION:
LS7232NT is a CMOS integrated circuit designed for brightness
control of incandescent lamps or tranformer coupled low voltage
halogen lamps. The brightness is controlled by controlling the firing angle of a triac in series with the lamp and triggered by the
LS7232NT. A Phase-Locked-Loop keeps the LS7232NT phase
pointer locked in phase with the line voltage.
A unique optical user interface provides for a smooth control of
the lamp intensity without the need for touching any sensor
plate. A mechanical switch interface for dimming control is also
provided which can be used for a remote touch plate. The IC includes features to address problems associated with inductive
loads such as transformers in low voltage halogen lamp application. The voltage to current phase lag resulting from the inductance may prevent the triac from shutting off at AC zero
crossover and/or prevent the triac from maintaining conduction
following the removal of the gate trigger. The inductive load
problems are addressed by the LS7232NT as follows:
1. Compensation for delayed triac cut-off.
When 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 dimmer IC. If the triac fails to fire, a
second trigger pulse of 260.4µs width is issued 1 ms later
as a second attempt to fire the triac during the same halfcycle.
3. Safety-Shutdown.
If the frequency of occurrences of the delayed cut-off and
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 cut-off or delayed turn-on and decrements once every 8 SYNC pulses (AC line cycles). The
count will not decrement below zero. If the count reaches
15, the safety-shut-down is effected.
7232NT-012703-1
January 2003
PIN ASSIGNMENT - TOP VIEW
CAP 1
14
V DD (+V)
SYNC 2
13
M2
ANODE 3
12
M1
11
RC
10
LEDO
SENS 6
9
TRIG/
REMOTE 7
8
Vss (-V)
CATHODE 4
LS7232NT
PHOTOUT 5
FIGURE 1
The LS7232NT can be configured in 7 different modes of dimming and timing off functions selected by two 3-state mode
pins.
INPUT/OUTPUT DESCRIPTION:
CAP (Pin 1)
PLL filter capacitor input. A 0.02µF capacitor is required at this
input for the optimal operation of the PLL.
SYNC (Pin 2)
The phase pointer for the triac trigger signal is synchronized
with the 50Hz/60Hz AC voltage applied at the SYNC input by
the internal PLL. The triac On/Off status information is also derived from this input.
ANODE (Pin 3) CATHODE (Pin 4) and PHOTOUT (Pin 5)
These three pins constitute the input/outputs of a transconductance and voltage amplifier pair (See Fig. 6) for converting the current from a photo-diode to a voltage stimulus for
application at the SENS input. The photo-signal is used in lieu
of a touch plate for a touchless dimmer system. The output at
PHOTOUT is governed by the following equation:
VOUT = VDD/2 + 2IDRf
Where VDD = Supply Voltage
ID = Current in Photo-diode connected between
ANODE and CATHODE
Rf = Feedback resistance between PHOTOUT
and CATHODE
A potentiometer is used for Rf for controlling the sensitivity of
the photo-amplifier system.
SENS (Pin 6)
A positive signal applied at the SENS input controls the turn-on,
turn-off and dimming function of the LS7232NT. The SENS input is designed to operate with very low levels of signal, so that
it can be directly interfaced with the photoamplifier output. Signal at the SENS input is amplified with a gain of 30. If a photosensor is not to be used, the SENS input can easily be adapted
to a touch plate.
Signals at the SENS input are classified as SHORT touch and
LONG touch. Signals between 50ms and 350ms constitute a
SHORT touch, whereas signals longer than 350ms constitute a
LONG touch. The functions of these two types of touches are
explained in the mode description section.
SENS input has an internal pull-down resistor of 10kΩ.
REMOTE (Pin 7)
For performing dimming operation from remote sites or through
wire extensions, the REMOTE input is used. This input is sampled twice during both negative and positive half cycles of the
AC, rendering it more immune to noise and hence more suited
for carrying signals over extension wires.
Vss (Pin 8)
Supply voltage, negative terminal.
TRIG/ (Pin 9)
Trigger ouput for driving the gate of a triac. A negative pulse of
nominally 130.2µs duration is generated at this output which
can be varied between 19.7° and 119.5° from the zerocrossover of the AC during every half cycle. The control of conduction angle of the TRIG/ output is effected by Short and Long
touches at the SENSE and REMOTE inputs.
LEDO (Pin 10)
A positive pulse of 32µs is generated at this output during every
negative half-cycle of the AC. If the TRIG/ output is Off, the
LEDO is generated nominally 911µs after the AC zerocrossover in the negative half-cycles. If the TRIG/ output is on,
the LEDO tracks the TRIG/ output signal and is generated
170µs ahead of the TRIG/ output, during every negative halfcycle of the AC.
The LEDO is used to drive an infra-red LED. When a reflecting
object, such as a human hand, is brought close to the infrared
LED, the light is reflected back to the Photo-diode, which is
mounted in physical proximity to the infra-red LED. The change
of intensity of the received light by the photo-diode results in a
change of the photo-diode current which in turn is amplified by
the transconductance amplifier as described in the ANODE
input section.
RC (Pin 11)
A resistor-capacitor pair connected externally to the RC input
constitutes the timing element for the delay generation in Modes
4, 5, 6, and 7. The delay is given by the expression, ∆ = 63RC.
M1 and M2 (Pin 12 and Pin 13)
Each of these inputs are 3-state inputs, namely Low (L), High
(H) and Float (F). The logic levels of these two inputs together,
configures the operating modes of the LS7232NT according to
Table 1.
MODE DESCRIPTIONS:
See Figures 2, 3, and 4 for further explanations.
MODE 1 - Touch causes the TRIG/ output to toggle between
Off and Max. The Off to Max transition slews in 350ms(tr). Long
and Short Touch operate in identical manner. Leading edge
touch sense (change occurs upon initiation of touch)
7232NT-012703-2
MODE 2 - Same effect for Short Touch as in Mode 1. Long Touch
causes the output to sweep between conduction angles of 38° (Min)
and 155° (Max) in increments of 1.4°. The sweep direction automatically reverses at Min and Max. Sweep direction also reverses for
every Long Touch. Trailing edge sensing for Short Touch. (Change
occurs upon removal of touch.)
MODE 3 - Same as Mode 2 except for Short Touch the output
toggles between Off and Memory. Memory is updated with the long
touch.
MODE 4 - Same as Mode 2 except the On to Off operation with
Short Touch is delayed. At the termination of the Short Touch the output level instantaneously drops by an amount of Ư to indicate the
beginning of the turn-off delay, t RC. At the end of the delay, the output
slews off at a rate of 56°/s. The delay tRC is controlled by a resistorcapacitor pair at the RC (Pin 11) input, according to the following
expression:
tRC = 63RC
The magnitude of Ư is dependent on the pre-touch intensity from
where the turn-off delay is initiated and can have one of the values in
Table 2 (See Fig. 2 and 3).
MODE 5 - Same as Mode 4, except a Short Touch in the Off state
switches the output to memory.
MODE 6 - Same as Mode 4, except that there is no dimming function in Mode 6. Both Short and Long touches operate as Short Touch
(leading edge touch sense).
MODE 7 - Output switches from Off to Max with either Short or Long
Touch (leading edge touch sense). After a delay of t RC = 63RC (See
description of Mode 4) the output drops by an angle Ư according to
Table 2. After another fixed delay of 10sec (tf ) the output slews off in
2sec (td7) at the rate of 56°/sec. A touch during t RC time out has no
effect. A touch during tf and t d7 timeouts aborts the timeout and
restores output to Max.
TABLE 1. OPERATING MODES
M1
M2
MODE
DESCRIPTION
L
L
1
ON - OFF
L
F
2
ON - OFF - DIMMER
L
H
3
ON - OFF - MEMORY - DIMMER
F
F
4
ON - DELAYED_OFF - DIMMER
F
H
5
ON - DELAYED_OFF - MEMORY-DIMMER
F
L
6
ON - DELAYED_OFF
H
L
7
ON - AUTO_OFF_TIMER
H
F
X
NOT ALLOWED
H
H
X
NOT ALLOWED
TABLE 2. BRIGHTNESS DROP AT DELAY START, Ư
PRE-TOUCH CONDUCTION ANGLE
155° to 130°
129° to 115°
114° to 95°
94° to 45°
44° to 38°
Ø
-35°
-25°
-20°
-10°
Instantaneous Off
ABSOLUTE MAXIMUM RATINGS:
PARAMETER
SYMBOL
DC Supply Voltage
VDD - VSS
Any Input Voltage
VIN
Operating Temperature
TA
Storage Temperature
TSTG
DC ELECTRICAL CHARACTERISTICS:
PARAMETER
Supply Voltage
Supply Current
VALUE
+7
Vss - 0.3 to VDD + 0.3
0 to +90
-65 to +150
UNIT
V
V
˚C
˚C
(TA = 25˚C, VDD = +5V, All voltages referenced to Vss)
SYMBOL
VDD
IDD
MIN
4.5
–
TYP
5.0
400
MAX
5.5
500
UNIT
V
µA
CONDITION
Output unloaded
Input Logic Levels:
SYNC Lo
SYNC Hi
REMOTE Lo
REMOTE Hi
SENS Lo
SENS Hi
-
3.0
3.5
150
–
–
–
–
–
–
2.0
1.5
50
-
V
V
V
V
mV
mV
-
RC Lo
RC Hi
-
3.0
-
2.0
-
V
V
-
Output Current:
LEDO Sink
LEDO Source
-
-1.0
10.0
-1.5
14.0
-
mA
mA
Vo = 0.5V
Vo = 2.2V
TRIG/ Sink
-
-35.0
-
-
mA
Vo = 3.5V
RC Sink
-
-3.0
-4.0
-
mA
Vo = 2.0V
TRANSIENT CHARACTERISTICS (See Figures 2, 3, 4 and 5):
All time parameters are based on 60Hz SYNC. For 50Hz a multiplication factor of 1.2 should be used.
PARAMETER
SYNC Frequency
SYMBOL
fs
MIN
40
TYP
-
MAX
70
UNIT
Hz
Short Touch
ts
50
-
350
ms
-
Long Touch
tL
350
-
infinite
ms
-
TRIG/ Pulse Width
TW
-
130.2
-
µs
-
Conduction Range
Ø
38
-
155
deg
-
Ø increments
Øs
-
1.4
-
deg
Short Touch:
Off to Max (Slew Time)
t1
-
350
-
ms
-
Long Touch:
Ramp Time between 38° & 59°
t2
-
1.0
-
sec
-
Ramp Time between 59° & 155°
t3
-
2.27
-
sec
-
Dwell at min
t4
-
500
-
ms
-
7232NT-012703-3
CONDITION
-
Ø = 84Øs
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
CONDITION
Timer Resistor
Timer Capacitor
Timer Delay
R
C
tRC
200
0.1
1e-3
10.0
-
2M
1200
Ohm
µF
sec
t RC ≈ 63RC
Slew Off Rate
tsf
Slew Off Delay
Pre-Off Delay (Mode 7)
Slew-Off Delay (Mode 7)
td
tf
td7
-
42
35
ØD/tsf
10
2
-
deg/sec
deg/sec
sec
sec
sec
60Hz
50Hz
-
LEDO Pulse Width
-
-
32
-
µs
-
SYNC to LEDO delay
tsl
-
918
-
µs
-
LEDO to TRIG/ delay
ttl
-
170
-
µs
-
LEDO to Strobe delay
tB
-
24
-
µs
-
SYNC
(Idealized)
Ø
Ø
Ø
TRIG/
tsl
t tl
tw
p1
p2
p1
p2
LEDO
tB
SENS_STROBE
(Internal)
NOTE: Pulse p1 and its associated sens_strobe occurs only when the TRIG/ is Off
Pulse p2 and its associated sens_strobe occurs only when the TRIG/ is On.
FIGURE 2. TRIG/ CONDUCTION ANGLE, Ø DEFINITION AND LEDO PULSE
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.
7232NT-012703-4
LONG
SHORT SHORT
SHORT
SHORT
LONG
LONG
SHORT
LONG
SENS
ts
ts
155
MODE 1
59
38
OFF
t1
NO MEMORY
155
MODE 2
tL
59
38
OFF
t4
t2
t3
155
MODE 3
MEMORY
59
38
OFF
FIGURE 3. MODES 1, 2 and 3
SHORT SHORT
SHORT SHORT
SHORT
SHORT
LONG
SHORT
SENS
tL
NO MEMORY
155
∆ø
MODE 4
59
t3
38
t RC
OFF
∆ø
t2
td
155
t4
MODE 5 59
MEMORY
38
OFF
FIGURE 4. MODES 4 and 5
SHORT SHORT
SHORT
SHORT
SENS
t RC
t RC
td
155
MODE 6
59
38
OFF
155
t1
t RC
tf
t d7
Ư
ts
MODE 7
59
38
OFF
7232NT-012703-5
FIGURE 5. MODES 6 and 7
CAP
1
SYNC
2
BUF
PHASE
LOCK
LOOP
CONTROL
PHASE
MEMORY
DIGITAL
COMPARATOR
TRIAC
STATUS
TRIGGER
LOGIC
9
DRIVER
TRIG/
Ø
POINTER
SENS
AMP
GAIN=30
6
10K
IR PULSE
LOGIC
PHOTOUT
CATHODE
LEDO
5
4
ANODE
3
REMOTE
7
M1
10
DRIVER
AMP
AMP
BUF
+V
14
V DD
-V
8
V SS
12
DECODER
M2
13
RC
11
TIMER
FIGURE 6. LS7232NT BLOCK DIAGRAM
FIGURE 7 . PHOTO AMPLIFIER WITH PHOTO DIODE AND GAIN RESISTOR , R f
+
AMP
-
100K
+
AMP
100K
VDD/2
VOUT = VDD/2 + 2IDRf
Id
3
ANODE
7232NT-012703-6
Rf
4
CATHODE
5
PHOTOUT (VOUT )
FIGURE 8. A TYPICAL DIMMER CIRCUIT WITH NO-TOUCH OPTICAL SENSING AND TOUCH PLATE OPTIONS
P
D3
R5
R6
R
N1
R7
G
MT1
D1
9
ANODE
SYNC
CAP
C2
TRIG/
RC
LS7232NT
C4
8
SEE
NOTE 3
V SS
10
R9
1
2
3
D2
4
5
6
R12
D4
R1
N
C3
P2
R11
R10
TOUCH
PLATE
7
L
R4
TOUCH
PLATE
P
R13
R2
R8
P1
REMOTE
11
SENS
12
LEDO
13
M1
14
M2
C
PHOTOUT
C1
C5
CATHODE
115VAC
OR
220VAC
Z
V DD
MT2
R14
T
C6
C7
R3
C8
LOAD
NOTES 1) For a No-Touch system, the infra-red transmit diode D3 and and receive D2 should be placed in physical proximity
so that when a hand is placed in front of D2 and D3, reflected light from the hand is received by the IR receiver D3 to produce a touch impulse.
2) If a touchplate is used the following parts should be in: R8, R9, C8 and P1.
If infrared detector is used the following parts should be in: D2, D3, R4, R5, R6, C7 and N1.
3) If remote sensing is not used the following parts may be removed: R3, R10, R11, R12, R13, C6 and P2.
If remote sensing is used these parts should be in and the connection between Pin 7 and Pin 8 must be broken.
4) The load is either an incandescent lamp or the primary of a step-down transformer for a low voltage halogen lamp.
220V (1)
115V
C = 0.1µF to 10µF, 10V
C1 = 0.15µF, 200V
C2 = 0.22µF, 200V
C3 = 0.02µF, 10V
C4 = 0.002µF, 10V
C5 = 200µF, 10V
C6 = 0.1µF, 10V
C7 = 0.003µF, 10V
C8 = 0.1µF, 10V
R1 = 270Ω, 1/2W
R2 = 680kΩ, 1/4W
R3 = 1.5MΩ, 1/4W
R4 = 500kΩ, 1/8W Pot.
R5 = 51Ω, 1/4W
R6 = 1kΩ, 1/4W
7232NT-012703-7
R = 200Ω to 2MΩ, 1/4W
R7 = 51Ω, 1/4W
R8, R9 = 2.7MΩ, 1/4W
R10, R11 = 2.7MΩ, 1/4W
R12 = 200kΩ, 1/4W
R13 = 2kΩ, 1/4W
R14 = 1 to 5MΩ, 1/4W
D1 = IN4148
D2 = SFH20S, IR Receiver diode
D3 = LD271, IR Transmitter diode
D4 = IN4148
Z1 = 5.6V, 1W (Zener)
T1 = Q2004L4 Triac (Typical)
L = 100µF, RFI Filter
N1 = MPS8099, NPN
P1, P2 = MPS8599
(1) All components are the same as 115V except as listed below:
C1 = 0.15µF, 400V
C2 = 0.22µF, 400V
R1 = 1kΩ, 1W
R2 = 1.5MΩ, 1/4W
R8, R9 = 4.7MΩ, 1/4W
T1 = Q4004L4 Triac (Typical)
L = 200µF, RFI Filter