FIGURE 5. A TYPICAL AUTO SHUT-OFF AC POWER SWITCH
P
SEE
NOTE 2
G
R5
R3
+
S1
C3
OFF
4
3
2
OFF
1
ON
ON
R4
R8
C7
MT1
T1
MT2
Z1
D1
-
L1
C2
AC
MAIN
S
C1
R2
TRIG V
DD
R6
R1
V
SS
5
A
B
LOAD
SEE
NOTE 1
R7
-
C6
+
OSC
6
LS7339
CAP SYNC
7
8
C5
C4
N
NOTES:
1.
Use Connection A when Neutral is not available.
Use Connection B when Neutral is available.
2.
Snubber Network C7, R8 may be required for
some inductive loads.
3.
See Table 2 for Component Functional Description.
115VAC
(1)(3)
R1
(2)(4)
R1
R2
R3
R4
R5
R6
R7
R8
C1
(1)
C2
(2)
C2
(3)
C2
(4)
C2
(1)(2)
C3
(3)(4)
C3
C4
C5
C6
C7
Z1
D1
L1
(7)T1
220VAC
FIGURE 6. PRODUCING VERY LONG TIME-OUTS BY PULSE MODULATING THE OSCILLATOR
-V
R2
Oscillator
Components
4
TRIG
D1
R1
Waveform A
+V
V
SS
D2
R3
C2
-
+
5
3
2
V
DD
OFF
LS7339
OSC CAP SYNC
6
7
8
1
ON
150Ω, 1W
360Ω, 2W
82Ω
82Ω
1.5MΩ
1.5MΩ
100kΩ
100kΩ
100kΩ
100kΩ
100Ω
100Ω
(5)(6)
(5)(6)
(5)(6)
(5)(6)
1.8kΩ, 1W
1.8kΩ, 2W
0.15µF, 200V 0.15µF, 400V
1.0µF, 200V 0.47µF, 400V
0.47µF, 200V 0.22µF, 400V
0.33µF, 200V 0.22µF, 400V
0.22µF, 200V 0.1µF, 400V
100µF
100µF
47µF
47µF
470pF
470pF
0.047µF
0.047µF
(6)
(6)
0.1µF, 200V 0.1µF, 400V
15V, 1/2W
15V, 1/2W
1N4148
1N4148
100µH
200µH
Q4008L4
Q5004L4
CD4093
C1 = 0.1µF
-V
T1
Waveform A
T2
Waveform B
T1
T1
≈
R1 C1
T2
≈
(R1 + R2)C1
Period = T1 + T2
Pulse Duty Cycle = T1/Period
Waveform B (Pulse Modulator)
Inverse of Pulse Duty Cycle = Period/T1 = 1 +T2/T1 = 2 + R2/R1
DESCRIPTION:
The Oscillator resistor is normally returned to the negative terminal of the DC Supply.
If this resistor is returned to a negative-going pulse instaed, the Oscillator R-C effectively
becomes multiplied by the inverse of the Pulse Duty Cycle because the Oscillator R-C can
chamge only while the pulse is present. (Pulse Modulation)
In Figure 6, The Oscillator R is R3, the Oscillator C is C2 and the Pulse Modulator is
Waveform B through isolation diode D2. The Multiplier, M = 2 + R2/R1 (the inverse of
the Pulse Duty Cycle).
EXAMPLE:
R3 = 5.1MΩ,
C2 = 1.0uF, Pulse Modulator = Waveform B
and desired T
D1
= 8 hours = 28,800 seconds.
Since T
D1
= 255 x M x R3 x C2, M calculates to be 22 for the selected
Oscillator Components. With M = 22, R2/R1 = 20. If R2 = 3MΩ, R1 = 150kΩ
(1)
LS7339, Connection A
(7)
Typical
(2)
LS7339, Connection B
(3)
LS7340, Connection A
(4)
LS7340, Connection B
(5)
100kΩ
≤
(R6 + R7)
≤10MΩ
(6)
(R6 + R7)C6
≥
5ms
All Resistors 1/4W, all Capacitors 25V
7339-012703-4
LSI [ LSI COMPUTER SYSTEMS ]
