JPH0389496A - Phase control device and dimming control device - Google Patents

Abstract

PURPOSE:To reduce heating and improve efficiency and safety by detecting the current flowing in a resistor forming the current path of a switching device, and changing the resistor according to the detected output. CONSTITUTION:When the control quantity of a dimming switch is set by a dimming switch control circuit 6, the conduction position control angle (theta) of a triode AC switch (TRIAC) 13 is set by the set content, the electric power from a AC power source 3 is controlled, and a discharge lamp 51 is lighted. When the theta of the TRIAC 13 is small, large electric power is fed, a large current flows in a resistor 61, a Zener diode 65 is turned on, a transistor(Tr) 67 is turned on, and the resistance value of a resistor means 60 is increased. When the theta of the TRIAC 18 is large, the current flowing in the resistor 61 is small, the diode 65 is in the reverse blocking state, Tr 67 is turned off, Tr 69 is turned on, and the resistance value of the means 60 is decreased. Heating is reduced and efficiency is improved when the output is large, and stability is improved when the output is low.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a phase control device for controlling the phase of an AC power supply and a dimming control device using this phase control device.

(Prior Art) As a conventional dimming control device of this type, for example, a circuit shown in FIG. 7 is known.

The configuration shown in FIG. 7 consists of a dimmer switch side unit 1 and a dimmer side unit 2, and the dimmer switch side unit 1 and the dimmer side unit 2 are connected by three wires. ing.

In this dimmer switch side unit 1, a constant voltage element 4 and a capacitor 5 are connected in parallel to a commercial AC power source 3, and a dimmer switch control circuit 6 is further connected. Also,
A beam actor 7 and a triac 8 are connected in series to one end of the commercial AC power supply 3, and a gate terminal of the triac 8 is connected to a dimmer switch control circuit 6. Then, at both ends of the commercial AC power supply 3 and one end of the triac 8,
Three output ends are formed.

Further, the light control device side unit 2 has three input ends,
A capacitor 11 is connected between the two wires connected to the commercial AC power supply 3.
is connected. Then, on this one line, actuator 12
A triac 13 as a switching device for controlling the phase of the output voltage is connected through the TRIAC 13. Further, a capacitor 15 and a resistor 16 are connected in series to the triac 13 in parallel to form a snubber circuit 14 . Further, a trigger signal control circuit 20 is connected between a line connected to the triac 8 and another line connected to the commercial AC power supply 3. This trigger signal control circuit 20
An AC input end of a rectifier circuit 21 such as a diode bridge is connected between the triac 8 and the other end of the commercial AC power supply 3, and a resistor 22 is connected between the DC output ends of the rectifier circuit 21.
, the anode and cathode of the photodiode 23 and the thyristor 24 are connected in series. Also, the resistor 22
and the connection point of the photodiode 23 and the rectifier circuit 21
A resistor 26 connected in series with the resistor 25 and a capacitor 27 are connected in parallel between the negative electrode of the thyristor 24 and the connection point of the cathode of the thyristor 24 . Furthermore, the resistor 26
A constant voltage element 28 is connected between the connection point of the capacitor 27 and the gate of the thyristor 24.
A resistor 29 is connected between the gate and cathode of 4.

A phototriac 31 photocoupled to the photodiode 23 and a resistor 32 are connected in series between the gate of the triac 13 and the other end of the commercial AC power supply 3. A resistor 33 is connected between the triac 31 and the connection point of the resistor 32.

A load 35 is connected to two wires from the commercial AC power source 3 and a line via the triac 13. This load 35 is connected to a primary winding 36 of a leakage transformer 38 having a negative winding 36 and a secondary winding 37 between a line passing through the triac 13 and a line from the other end of the commercial AC power supply 3.
is connected between the two wires connected to the commercial AC power supply 3, -
A primary winding 41 of a transformer 44 having a secondary winding 41, a first secondary winding 42 and a second secondary winding 43 is connected. Further, one end of the secondary winding 37 of the leakage transformer 38 is connected to a capacitor 45 and a resistor 46 connected in series.
is connected to one end of the primary winding 41 of the cage transformer 44, and the other end of the secondary winding 37 is connected to a lighting load such as a fluorescent lamp through a capacitor 47 and a resistor 48 connected in parallel. One filament 52 of the discharge lamp 51
The other end of this one filament 52 is connected to one end of the first secondary winding 42, and the other end of this first secondary winding 42 is connected to a capacitor 47, a resistor 48 and one end of the filament 52. The filament 52 is connected to a connection point at one end of the filament 52 . Further, one end of the other filament 53 of the discharge lamp 51 is connected to one end of the second secondary winding 43, and the other end of the other filament 53 is connected to the other end of the second secondary winding 43 and the commercial AC It is connected to the other end of the power supply 3.

Next, the operation of the circuit shown in FIG. 7 will be explained.

First, the conduction control phase angle of the triac 8 is set in the dimmer switch control circuit 6, and the triac 8 is turned on and off according to this conduction control phase angle, and the trigger signal control circuit 20
A phase angle controlled alternating current is supplied to the In the trigger signal control circuit 20, the rectifier circuit 21 rectifies the signal, and the capacitor 2
7, and when the voltage of this capacitor 27 exceeds a predetermined value, the constant voltage element 28 becomes conductive, turning on the thyristor 24, lighting the photodiode 23, and turning on the phototrial 31. A gate voltage is applied to the triac 13 to turn on the triac 13.

For example, by decreasing the conduction control phase angle of the triac 8, the charging time of the capacitor 27 is shortened, and by decreasing the conduction control phase angle of the triac 13, the output is increased. On the other hand, by increasing the conduction control phase angle of the triac 8, the charging time of the capacitor 27 is increased, and the conduction control phase angle of the triac 13 is increased, thereby reducing the output.

(Problem to be Solved by the Invention) However, in the case of the circuit shown in FIG. When using a resistor (it must be 1), it has problems with heat generation and poor efficiency.On the other hand, if the output is lowered and the current flowing through the resistor 32 is reduced, the current given to the triac 13 is reduced. becomes less than the holding current, and the operation of the triac 13 becomes unstable.

The present invention was developed in view of the above problems, and does not cause heat generation or decrease in efficiency even when the output is increased, and does not cause unstable operation even when the output is decreased. It is an object of the present invention to provide a phase control device and a dimming control device.

[Structure of the invention]

(Means for Solving the Problems) A phase control device according to claim 1 comprises: an AC power source; a switching device having a trigger terminal and capable of controlling the phase of the output voltage of the AC power source; and a trigger terminal of the switching device. and a resistance means connected between the AC power source, a trigger signal control circuit that supplies a control signal to a trigger terminal of the switching device, and a load supplied with the phase control output of the switching device, The resistance means includes current detection means for detecting the current flowing through the resistance means, and variable resistance means for changing the impedance of the resistance according to the output of the current detection means.

A phase control device according to a second aspect of the present invention includes: an AC power source; a switching device whose end is connected to one end of the AC power source; a resistor means forming a path for passing a current through the switching device; and a load supplied with the phase control output of the switching device, and the resistance means includes current detection means for detecting the current flowing through the resistance means, and a variable resistor for changing the impedance of the resistance according to the output of the current detection means. It is equipped with means.

A dimming control device according to a third aspect uses a lighting load as the load, and uses the phase control device according to the first or second aspect.

(Function) The phase control device according to the first aspect controls the phase of AC power from an AC power source using a switching device according to a control signal from a trigger signal control circuit, and applies it to a load.

The current flowing through the resistance means connected to the trigger terminal is detected by the current detection means, and the impedance of the resistance means is changed by the variable resistance means according to the output of the current detection means.

The phase control device according to the second aspect subjects the AC power of the AC power source to phase control using a switching device and supplies it to a load. The current flowing through the resistance means connected to the load is detected by the current detection means, and the impedance of the resistance means is changed by the variable resistance means according to the output of the current detection means.

A dimming control device according to a third aspect of the present invention controls a lighting load using the phase control device according to the first or second aspect.

(Example) Hereinafter, a dimming control device according to an example of the present invention will be described with reference to the drawings. Note that the same parts as those in the conventional example shown in FIG. 7 are given the same reference numerals, and the explanation thereof will be omitted.

In the circuit shown in FIG. 1, in place of the resistor 32 in FIG.
A resistance means 60 is used.

This resistance means 60 has a resistor 6I connected between the phototriac 31 and the other end of the AC power source 3, an AC input end of a rectifier circuit 62 connected to both ends of this resistor 61, and a DC output end of the rectifier circuit 62 connected to both ends of the resistor 61. A current detection means 63 for detecting the current flowing through the resistor fi+ and a variable resistance means 64 for changing the resistance value of the resistance means 6G are connected to the resistor fi+. In the current detection means 63, a series circuit of a Zener diode 65 and a resistor 66 is connected to the positive terminal of the DC output terminal of the rectifier circuit 62, and a variable resistance means 64 is connected to the resistor 66. This variable resistance means 64 has a resistor 6G connected to the base of a transistor 67, and this transistor 6G.
A resistor 68 is connected between the base and emitter of the transistor 7, the emitter is connected to the negative electrode of the rectifier circuit 62, and the collector is connected to the base of the transistor 69. Further, a resistor 70 is connected between the base and collector of the transistor 69, and the collector is connected to the positive electrode of the rectifier circuit 62 via a resistor 71.

Next, the operation of the circuit shown in FIG. 1 will be explained.

First, the dimmer switch control circuit 6 sets the control amount of the dimmer switch. Triac 8
conducts, charges the capacitor 27 of the trigger signal control circuit 20, turns on the thyristor 24 as the capacitor 27 is charged, turns on the photodiode 23, turns on the phototriac 31, and triggers the triac 13. That is, the conduction phase control angle of the triac 13 is set according to the contents set in the dimmer switch control circuit 6, the electric power from the AC power supply 3 is controlled, and the discharge lamp 51 is turned on.

When the conduction phase control angle of the triac 13 is small, a large amount of power is supplied and the current flowing through the resistor 61 is also large, so the Zener diode 65 is turned on, supplying current to the base of the transistor 67, and turning on the transistor 67. By bypassing the base of the transistor 69 and bypassing the current flowing between the collector and emitter of the transistor 69 to the resistor 71, the resistance value of the resistance means 60 is increased.

Conversely, when the conduction phase control angle of the triac 13 is large, small power is supplied and the current flowing through the resistor 61 is also small, so the Zener diode 65 is in a reverse blocking state, the transistor 67 remains off, and the transistor 6
9 is turned on to reduce the resistance value of the resistance means 60.

Next, another embodiment will be described with reference to FIG.

The circuit shown in FIG. 2 is similar to the resistor 61 of the circuit shown in FIG.
A resistor 72 is provided in series with the rectifier circuit 6.
2, current detection means 63 and variable resistance means 64
It has been established.

The circuit operates in the same manner as the circuit shown in FIG.

Further, another embodiment will be described with reference to FIG.

The circuit shown in FIG. 3 is similar to the resistor 72 of the circuit shown in FIG.
, the AC input end of a rectifier circuit 62 is connected in series with the resistor 61.

The circuit shown in FIG. 3 operates similarly to the circuit shown in FIG. 2.

Next, an embodiment in which a resistance means 82 is connected between the triac 13 and the other end of the AC power supply 3 will be described.

In the circuit shown in FIG. 4, a resistor means 80 is connected between the other end of the triac 13 and the other end of the AC power source 3 in place of the resistor 33 shown in FIG.

This resistance means 80 has a resistor 81 connected between the other end of the triac 13 and the other end of the AC power supply 3, and a resistor 83 as a variable resistance means 82 and a switch 84 connected in series between both ends of this resistor 81. Connect the circuit and switch this switch 8
4 is adapted to operate according to current detection means 85 connected to both ends of resistor 81.

When the power controlled by the triac 13 is large and a large current is flowing through the resistor 81, the switch 8
4 is closed to increase the resistance value of the resistance means 80. Conversely, when the current is small, the switch 84 is opened and the resistor 83 is connected in parallel to the resistor 81 to decrease the resistance value.

Further, another embodiment will be described with reference to FIG.

This resistance means 80 has a series circuit of a resistor 81 and a resistor 86 connected between the phototriac 13 and the other end of the commercial AC power supply 3, and a rectifier circuit 87 connected to both ends of the resistor 86.
The AC input terminal of the rectifier circuit 87 is connected to the DC output terminal of the rectifier circuit 87, and a current detection means 85 for detecting the current flowing through the resistor 86 and a variable resistance means 82 for changing the resistance value of the resistance means 80 are connected between the DC output terminals of the rectifier circuit 87. There is. The current detection means 85 is
A series circuit of a Zener diode 88 and a resistor 89 is connected to the positive terminal of the DC output end of the rectifier circuit 87.
9 is connected to variable resistance means 82. In this variable resistance means 82, the base of a transistor 90 is connected to a resistor 89, a resistor 91 is connected between the base and emitter of this transistor 90, the emitter is connected to the negative electrode of the rectifier circuit 87, and the collector is connected to the base of the transistor 92. It is connected to the. Also, the base of the transistor 92
A resistor 93 is connected between the collectors;
4 to the positive electrode of the rectifier circuit 87.

The circuit shown in FIG. 5 operates in the same manner as in FIG. 4.

Furthermore, FIG. 6 shows another embodiment in which the AC input end of a rectifier circuit 87 is connected in place of the resistor 86 of the circuit shown in FIG.

The circuit shown in FIG. 6 also operates in the same manner as the circuit shown in FIG.

Furthermore, in any of the above embodiments, the switching device 13 is not limited to a triac, but may also be a thyristor connected in antiparallel, a thyristor connected to a diode bridge, or the like.

Furthermore, an incandescent lamp or the like may be used as the load 35.

〔Effect of the invention〕

According to the present invention, the resistance value is changed according to the amount of current flowing through the resistor, so even when the output is high, there is little heat generation and the efficiency is high, and even when the output is low, the switching device Since the holding current never drops below the holding current, the operation can be stabilized.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, Fig. 2 is a partial circuit diagram showing another embodiment of the same as above, Fig. 3 is a partial circuit diagram showing another embodiment of the same as above, and Fig. 4 is a circuit diagram showing another embodiment of the same as above. FIG. 5 is a partial block diagram showing yet another embodiment, FIG. 5 is a partial circuit diagram showing yet another embodiment, FIG. 6 is a partial circuit diagram showing another embodiment, and FIG. 7 shows a conventional example. It is a circuit diagram. 3. AC power supply, 13. Triac as a switching device, 20. Trigger signal control circuit, 35. Load, 51. Fluorescent lamp as lighting load, 60° 80.
Resistance means, 63.85...Current detection means, 64°82.
- Variable resistance means.

Claims (3)

[Claims] (1) an AC power source; a switching device having a trigger terminal and capable of controlling the phase of the output voltage of the AC power source; a resistor connected between the trigger terminal of the switching device and the AC power source; a trigger signal control circuit that supplies a control signal to a trigger terminal of a switching device; and a load that is supplied with a phase control output of the switching device; and variable resistance means for changing the impedance of the resistor according to the output of the current detection means. (2) an alternating current power supply; a switching device having one end connected to one end of the alternating current power supply; a resistance means forming a path for conducting current through the switching device; and supplying a phase control output of the switching device. The resistance means includes a current detection means for detecting the current flowing through the resistance means, and a variable resistance means for changing the impedance of the resistance according to the output of the current detection means. phase control device. (3) A dimming control device characterized in that the load is a lighting load and the phase control device according to claim 1 or 2 is used.