CA3059

Manufacturer Part NumberCA3059
DescriptionZERO VOLTAGE CROSSING SWITCH
ManufacturerIntersil
CA3059 datasheet
 


Specifications of CA3059

Rohs StatusRoHS non-compliant  
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biased to inhibit output pulses. When the push button is
depressed, pulses are generated, but the state of Q
determines the requirement for their supply to the triac gate.
The first pulse generated serves as a “framing pulse” and
does not trigger the triac but toggles FF-1. Transistor Q
then turned off. The second pulse triggers the triac and FF-1
which, in turn, toggles the second flip-flop FF-2. The output
of FF-2 turns on transistor Q
, as shown in Figure 55, which
7
inhibits any further output pulses. When the push-button is
released, the circuit resets itself until the process is repeated
with the button. Figure 56 shows the timing diagram for the
described operating sequence.
Phase Control Circuit
Figure 57 shows a circuit using a CA3059 zero-voltage
switch together with two CA3086 integrated circuit arrays to
form a phase control circuit. This circuit is specifically
designed for speed control of AC induction motors, but may
also be used as a light dimmer. The circuit, which can be
operated from a line frequency of 50Hz to 400Hz, consists of
a zero-voltage detector, a line synchronized ramp generator,
a zero current detector, and a line derived control circuit (i.e.,
the zero-voltage switch). The zero-voltage detector (part of
CA3086 No. 1) and the ramp generator (CA3086 No. 2) pro-
vide a line synchronized ramp voltage output to terminal 13
of the zero-voltage switch. The ramp voltage, which has a
starting voltage of 1.8V, starts to rise after the line voltage
passes the zero point. The ramp generator has an oscillation
frequency of twice the incoming line frequency. The slope of
the ramp voltage can be adjusted by variation of the resis-
tance of the 1M
ramp control potentiometer. The output
phase can be controlled easily to provide 180
triac by programming the voltage at terminal 9 of the zero-
voltage switch. The basic operation of the zero-voltage
switch driving a thyristor with an inductive load was
o
30
V
1
RANDOM
START-UP
POINT
V
2
o
30
V
3
o
90
SINGLE PHASE START-UP
(ZERO-VOLTAGE)
FIGURE A.
NOTE: The dashed lines indicate the normal relationship of the phases under steady state conditions. The deviation at start up and turn off
should be noted.
FIGURE 59. VOLTAGE PHASE RELATIONSHIP FOR A THREE PHASE RESISTIVE LOAD WHEN THE APPLICATION OF LOAD POW-
ER IS CONTROLLED BY ZERO-VOLTAGE SWITCHING: A. VOLTAGE WAVEFORMS, B. LOAD CIRCUIT ORIENTATION
OF VOLTAGES.
Application Note 6182
explained previously in the discussion on switching of induc-
tive loads.
G
On/Off Touch Switch
is
G
The on/off touch switch shown in Figure 58 uses the CA3240E
to sense small currents flowing between two contact points on
a touch plate consisting of a PC board metallization “grid”.
When the on plate is touched, current flows between the two
halves of the grid, causing a positive shift in the output voltage
(terminal 7) of the CA3240E. These positive transitions are fed
into the CA3059, which is used as a latching circuit and zero
crossing triac driver. When a positive pulse occurs at terminal
No. 7 of the CA3240E, the triac is turned on and held on by the
CA3059 and associated positive feedback circuitry (51k resis-
tor and 36k /42k voltage divider). When the pulse occurs at
terminal No. 1, the triac is turned off and held off in a similar
manner. Note that power for the CA3240E is derived from the
CA3059 internal power supply. The advantage of using the
CA3240E in this circuit is that it can sense the small currents
associated with skin conduction while maintaining sufficiently
high circuit impedance to protect against electrical shock.
Triac Power Controls for Three
Phase Systems
This section describes recommended configurations for
power control circuits intended for use with both inductive
and resistive balanced three phase loads. The specific
design requirements for each type of loading condition are
discussed.
In the power control circuits described, the integrated circuit
o
firing of the
zero-voltage switch is used as the trigger circuit for the
power triacs. The following conditions are also imposed in
the design of the triac control circuits:
GATE DRIVE
REMOVED
o
30
o
30
SINGLE PHASE
o
90
TURN-OFF
28
V
V
3
1
PHASE
V
2
ROTATION
FIGURE B.