CA3059 Intersil, CA3059 Datasheet - Page 24

• Manufacturer Part Number: CA3059
• Description: ZERO VOLTAGE CROSSING SWITCH
• Manufacturer: Intersil

Specifications of CA3059

• Rohs Status: RoHS non-compliant

120V
on by the logical “1” (V
The arrangement describe can also be used for a synchro-
nous, sequential traffic controller system by addition of one
triac, one gating transistor, a “divide-by-three” logic circuit,
and modification in the design of the diac pulse generator.
Such a system can control the familiar red, amber, and
green traffic signals that are found at many intersections.
Synchronous Light Flasher
Figure 50 shows a simplified version of the synchronous
switching traffic light flasher shown in Figure 49. Flash rate is
set by use of the curve shown in Figure 16. If a more precise
flash rate is required, the ramp generator described
previously may be used. In this circuit, ZVS
control unit and ZVS
its inhibit terminal (terminal 1). When power is applied to
lamp No. 1, the voltage of terminal 6 on ZVS
ZVS
off, ZVS
supplies operate in parallel. The on/off sensing amplifier in
ZVS
Transient Free Switch Controllers
The zero-voltage switch can be used as a simple solid-state
switching device that permits AC currents to be turned on or
off with a minimum of electrical transients and circuit noise.
The circuit shown in Figure 51 is connected so that, after the
control terminal 14 is opened, the electronic logic waits until
the power line voltage reaches a zero crossing before power
is applied to the load Z
nals are shorted, the load current continues until it reaches a
zero crossing. This circuit can switch a load at zero current
whether it is resistive or inductive.
The circuit shown in Figure 52 is connected to provide the
opposite control logic to that of the circuit shown in Figure
60Hz
AC
2
2
VDC
100
is not used.
15
is inhibited by the current in R
F
FIGURE 50. SYNCHRONOUS LIGHT FLASHER
2
is not inhibited, and triac Y
1/2 W
14
13
8
2
7
5W
5K
ZVS
9
3
2
CC
10
is slaved to the output of ZVS
5
L
1
. Conversely, when the control termi-
high) state of the flip-flop.
11
6
LAMP 1
12
IC
1
1
4
Y
G
1
MT
MT
2
1
X
2
14
. When lamp No. 1 is
13
8
can fire. The power
2
7
3
ZVS
9
1
10
Application Note 6182
5
is the master
2
1
11
is high and
6
LAMP 2
IC
12
1
1
2
through
R
20K
4
X
Y
G
2
MT
MT
2
1
24
51. That is, when the switch is closed, power is supplied to
the load, and when the switch is opened, power is removed
from the load.
In both configurations, the maximum rms load current that
can be switched depends on the rating of triac Y
Differential Comparator for Industrial Use
Differential comparators have found widespread use as limit
detectors which compare two analog input signals and
provide a go/no-go, logic “one” or logic “zero” output,
depending upon the relative magnitudes of these signals.
Because the signals are often at very low voltage levels and
very accurate discrimination is normally required between
them, differential comparators in many cases employ
differential amplifiers as a basic building block. However, in
many industrial control applications, a high performance
differential comparator is not required. That is, high
resolution, fast switching speed, and similar features are not
essential. The zero-voltage switch is ideally suited for use in
such applications. Connection of terminal 12 to terminal 7
inhibits the zero-voltage threshold detector of the zero-
voltage switch, and the circuit becomes a differential
comparator.
Figure 53 shows the circuit arrangement for use of the zero-
voltage switch as a differential comparator. In this
application, no external DC supply is required, as is the case
with
comparators; of course, the output current capability of the
zero-voltage switch is reduced because the circuit is
operating in the DC mode. The 1000
connected between terminal 4 and the gate of the triac,
most
commercially
available
integrated
resistor R
2
.
circuit
G
,