TW201336350A - Two-wire dimmer switch - Google Patents

Abstract

A two-wire dimmer switch comprising: a main switching circuit 10 that uses a TRIAC 11 as the main switching element, a frequency detection circuit 17 which detects a frequency of an AC power source 2, an auxiliary switching circuit 18, having a thyristor as the auxiliary switching element, which causes a load current to flow when the primary switching element is not conducting, a light intensity setting circuit 4 controlled by a user, and a control circuit 16, which estimates the zero cross voltage by detecting the frequency of the AC power source 2 based on the detection signal of the frequency detection circuit 17, starts output of a drive signal that opens the auxiliary switching circuit 18 at a first timing, and stops output of the drive signal at a second timing preceding the next estimated zero cross voltage by a predetermined time, wherein when the load current is small and the main switching circuit 10 becomes nonconductive, a load current continues to flow in the auxiliary switching circuit 18. By employing this configuration, even if an LED light bulb is connected as the lighting load, the brightness of the LED light bulb can be stabilized, and flickering and fluctuation can be minimized.

Description

Two-wire dimmer switch

The present invention is related to a two-wire dimmer switch for the purpose of adjusting the brightness of a lighting load.

Conventionally, dimmer switches using semiconductor switching elements such as bidirectional triodes have been put to practical use for the purpose of dimming light bulbs. Fig. 8 is a basic circuit configuration (first conventional example) of the two-wire dimmer switch 50 using the bidirectional triode 51. The two-wire dimmer switch 50 is connected in series to the AC power source 2 and the lighting load (bulb) 3. The two-wire dimmer switch 50 is connected to the bipolar body 51 and the gate electrode connected to the bidirectional body 51 for inputting a gate driving signal, for example, a two-terminal AC switch (trigger diode) 52, connected to The variable resistor 53 of the operating member operated by the user, the fixed resistor 54, the capacitor 55, and the filter element 56 are formed.

When the two-wire dimmer switch 50 is turned on, the capacitor 55 is charged by the AC power source 2 via the variable resistor 53. When the voltage across the capacitor 55 reaches the turning voltage of the two-terminal AC switch 52, the two-way three-way is turned on. Polar body 51. Next, the bidirectional transistor 51 performs arc suppression at the voltage zero crossing point of the alternating current power source. That is, during each half cycle of the AC power supply, the triggering (conduction) and self-extinguishing (non-conduction) of the triac 51 are repeatedly performed by the two-terminal AC switch 52. The dimming of the illumination load 3 can be performed by adjusting the resistance value of the variable resistor 53 to perform phase control during the ignition of the triac 51.

The two-wire dimmer switch 50 of the first conventional example is because the electric power of the variable resistor 53 is changed. The resistance is used to perform the dimming of the illumination load 3, and the loss caused by the variable resistor 53 is large. Further, since the voltage of the AC power source 2 is directly applied to the variable resistor 53, the variable resistor 53 itself cannot be miniaturized, and the miniaturization of the two-wire dimmer switch 50 has its limit. Further, when another device connected to the same AC power source 2 operates, the AC power source 2 changes in voltage, and the brightness of the illumination load 3 changes instantaneously.

In order to solve the problem of the two-wire type dimmer switch 50 of the first conventional example, Japanese Laid-Open Patent Publication No. Hei 11-67479 proposes to control the timing of turning on the semiconductor switching elements by using a microcomputer or the like, that is, controlling the output gate driving. Dimming switch for timing of signals. Further, although the dimmer switch is a three-wire type, FIG. 9 is a circuit configuration (second conventional example) applied to the two-wire dimmer switch.

In the second-line dimmer switch 60 of the second conventional example, the secondary side optical triode 63 of the optical triac coupler 62 is connected to the gate electrode of the bidirectional triode 61. Further, the rectifier circuit 65 is connected between the other electrodes of the bidirectional body 61, and the electric power that is subjected to full-wave rectification via the rectifier circuit 65 is input to the power supply unit 66. The control unit 67 is driven by DC power converted by the power supply unit 66. Here, the voltage of the alternating current power source 2 is applied to the rectifier circuit 65, for example, alternating current (AC) 100V is applied. On the other hand, the control unit 67 is driven by, for example, direct current (DC) of 3 to 6V. The optical triac coupler 62 optically insulates the control unit 67 from the semiconductor switching element 61. The control unit 67 conducts the current-carrying crystal 69 at a timing stored in advance in the look-up table in correspondence with the resistance value of the variable resistor 68 connected to the operation member operated by the user. When the transistor 69 is turned on, current flows through the light-emitting diode 64 on the primary side of the optical triac coupler 62, and the secondary side optical triode 63 is turned on. When the secondary side light bidirectional body 63 of the optical triac coupler 62 is turned on, the load current starts to flow, and at the same time, the gate voltage of the bidirectional body 61 rises. When the gate voltage of the triac 61 is equal to or greater than the threshold value, the bidirectional body 61 is turned on, and the current flowing from the AC power source 2 through the illumination load 3 is applied to the optical bidirectional body 63 in the two-wire dimmer switch 60. Turning to the bidirectional transistor 61, the optical triode 63 becomes non-conductive.

In recent years, LED bulbs using LEDs (Light Emitting Diodes) instead of bulbs have been put to practical use. At the same time, in the LED bulb, the dimmable material has also been put into practical use. Relative to the bulb resistor The LED bulb, as shown in Fig. 10, is composed of a plurality of LED elements and their driving circuits. The LED drive circuit 70 is a rectifier circuit 71 that performs rectification of AC power, an inductor 72, a snubber capacitor 73 for storing power, an LED array 77, and a capacitor 76 connected in parallel to the LED array 77 to allow a constant current to flow. The LED array 77 is a FET (Field Effect Transistor) 75, a drive IC 74, and the like. That is, the LED bulb, the load is an electronic circuit composed of a diode and an IC. Fig. 11(a) shows the waveforms of the load voltage and load current of the bulb of 1/2 cycle of the AC power supply, and Fig. 11(b) shows the waveform of the load voltage and load current of the LED bulb. The bulb has a power factor of 1, and the voltage and current systems exhibit approximately the same waveform. On the other hand, in the case of an LED bulb, the load current is mainly for the purpose of charging the capacitor 73, and the bidirectional triode is turned on at the same time as it is instantaneously large, but is immediately smaller.

When the dimming control of the LED bulb exhibiting the above characteristics is performed by the two-wire dimmer switch 50 of the first conventional example, the following problems are caused. Fig. 12 is a view showing a problem in which the dimming control of the LED bulb is performed by the two-wire dimmer switch 50 of the first conventional example. As shown in Fig. 12, when the bidirectional triode 51 is turned on, a large load current flows instantaneously, but it becomes small immediately. When the value of the load current is equal to or lower than the holding current of the bidirectional transistor 51, the bidirectional triode 51 is self-extinguishing and is non-conductive. When the bidirectional transistor 51 is non-conducting, the voltage of the capacitor 73 drops, and the driving IC 74 controls to reduce the current flowing through the FET 75. In this case, the current flowing through the LED array 77 is reduced, and the brightness of the LED bulb is lowered. Further, the influence of the noise superimposed on the AC power source 2 causes the load current to temporarily become small. As shown in FIG. 13, when the operation of the other device connected to the same AC power source 2 causes a voltage fluctuation of the AC power source 2, the LED bulb is The brightness is reduced.

On the other hand, in the second-line dimming switch 60 of the second conventional example, when the current continues to flow through the optical bidirectional body 63 on the secondary side of the optical triac coupler 62, the load current can continue to flow. However, since a current of several mA to several tens of mA flows through the optical triac 63, it takes a lot of power to maintain a long-time conduction. In particular, in essence, since the LED bulb is an electronic circuit as described above, the power consumption is small, and if the two-wire dimmer switch 60 side consumes a large amount of electric power, it may be in an uncontrollable state.

The present invention has an object to solve the above-described problems of the conventional example, and an object thereof is to provide a two-wire dimmer switch that can stabilize the brightness, flicker, and fluctuation of the LED bulb even when the LED bulb is connected as a lighting load.

The two-wire dimmer switch of the present invention is connected in series to an AC power supply and a lighting load, and is characterized in that: a first connection terminal and a second connection terminal to which AC power is input; and a connection between the first connection terminal and the second connection terminal Between the connection terminals, a first semiconductor switching element is used as a main switching circuit of the main switching element, a rectifying circuit is connected between the first connecting terminal and the second connecting terminal, and is connected to a DC side of the rectifying circuit to ensure the aforementioned a power supply circuit of the internal power supply of the two-wire dimmer switch; a frequency detection circuit connected to the DC side of the rectifier circuit for outputting a specific detection signal for detecting the frequency of the AC power supply; and being coupled to the DC side of the rectifier circuit or On the AC side, the second semiconductor switching element is used as an auxiliary switching element, and when the main switching element is not turned on, a load current flows, and a gate driving signal for turning on the main switching element or another semiconductor switching element is output. Auxiliary switch circuit; operated by a user to set to adjust the brightness of the aforementioned lighting load a dimming amount setting circuit for the purpose of adjusting the amount of light; and detecting the frequency of the alternating current power source based on the detection signal outputted by the frequency detecting circuit, and estimating a voltage zero crossing point of the alternating current power source to be set by the dimming amount a dimming amount set by the circuit and a first timing determined according to the estimated voltage zero-crossing point, starting to output a driving signal for turning on the auxiliary switching circuit, and estimating the voltage zero crossing point The voltage zero crossing point is a control circuit that stops the output of the drive signal at a second timing before a specific time.

Further, the gate driving signal outputted by the auxiliary switching circuit is turned on, and after the auxiliary switching circuit is turned on, when the main switching element is not turned on, a load current flows, and an output is turned on to turn on the main The switching element is a quasi-main switching circuit for the purpose of the driving signal; preferably.

Further, the main switching element is a bidirectional triode, and the auxiliary switching circuit is connected to Preferably, the thyristor on the DC side of the rectifier circuit is an auxiliary switching element.

Further, the main switching element is a bidirectional triode, and the auxiliary switching circuit is preferably an auxiliary switching element that is connected to the alternating current side of the rectifying circuit and can be alternately turned on according to the polarity of the alternating current power source.

Further, the above-mentioned quasi-main switching circuit uses an optical bidirectional triode coupler as a switching element, and connects the optical bidirectional triode on the secondary side of the optical bidirectional triode coupler in parallel with the main switching element, and One of the terminals is connected to the gate terminal of the main switching element, and the light-emitting diode of the primary side of the optical two-way three-pole coupler is connected in series to the auxiliary switching circuit, and the holding current of the optical two-way three-pole body The value of the holding current is smaller than the value of the holding current of the aforementioned bidirectional triode.

Preferably, when the dimming control of the illumination load is started, the control circuit outputs an initial driving signal for turning on the auxiliary switching circuit at a specific timing near the estimated voltage zero crossing point.

According to the above-described two-wire dimmer switch, an auxiliary switch circuit that outputs a gate drive signal for turning on a main switching element or another semiconductor switching element when a main switching element is not turned on is provided; The driving signal of the conduction auxiliary switching circuit is continuously continued from the first timing determined by the dimming amount set by the dimming amount setting circuit and the voltage zero crossing point to the second timing before the specific time. The next voltage zero crossing point is output, and the auxiliary switching circuit is maintained in an on state. Therefore, the illumination load is an LED bulb, and after the load current flows from the auxiliary switch circuit or the like to the main switch circuit, the load current value becomes lower than the holding current of the main switching element, and the auxiliary switch circuit can be passed through even if the main switch circuit becomes non-conductive. Wait until the load current continues to flow. As a result, the brightness of the LED bulb can be stabilized, and flicker and fluctuations can be reduced.

1A, 1B, 1C, 1D‧‧‧ two-wire dimmer switch

1a‧‧‧1st connection terminal

1b‧‧‧2nd connection terminal

2‧‧‧AC power supply

3‧‧‧Lighting load

4‧‧‧Dimming amount setting circuit (variable resistor)

5‧‧‧ switch

10‧‧‧Main switch circuit

11‧‧‧Main switching element (bidirectional triode)

12‧‧‧Rectifier circuit

13‧‧‧Power circuit

13a‧‧‧1st transistor component

13b‧‧‧2nd transistor component

13c‧‧‧Zina diode

13d‧‧‧resist

14‧‧‧ Constant voltage circuit

15‧‧‧ snubber capacitor

16‧‧‧Control circuit

17‧‧‧ Frequency detection circuit

17a‧‧‧Optoelectronic components

18, 18a, 18b‧‧‧Auxiliary switch circuit (auxiliary switching element, thyristor)

20‧‧‧Quasi-main switching circuit (optical two-way triode coupler)

21‧‧‧Light bidirectional triode

22‧‧‧Lighting diode

25a, 25b‧‧‧ diode

50, 60‧‧‧2-wire dimmer switch

51, 61‧‧‧ bidirectional triode

52‧‧‧Two-terminal AC switch

53‧‧‧Variable Resistor

54‧‧‧Fixed resistor body

55, 76‧‧‧ capacitor

56‧‧‧Filter components

57‧‧‧ conduction switch

62‧‧‧Light bidirectional triode coupler

63‧‧‧Second side light bidirectional triode

64‧‧‧Light-emitting diodes on the primary side

65‧‧‧Rectifier circuit

66‧‧‧Power Supply Department

67‧‧‧Control Department

68‧‧‧Variable Resistor

69‧‧‧Optoelectronics

70‧‧‧LED drive circuit

71‧‧‧Rectifier circuit

72‧‧‧Inductors

73‧‧‧ snubber capacitor

74‧‧‧Drive IC

75‧‧‧FET (Field Effect Transistor)

77‧‧‧LED array

Fig. 1 is a circuit diagram showing the configuration of a two-wire dimmer switch according to a first embodiment of the present invention.

Fig. 2 is a waveform diagram of a load voltage, a load current, and a gate drive signal for turning on the thyristor of the auxiliary switch circuit of the LED lamp of the first embodiment.

Fig. 3 is a waveform diagram showing load voltages, load currents, and gate drive signals for turning on the sluice fluid of the auxiliary switch circuit, which are affected by the load current of the other devices of the first embodiment.

Fig. 4 is a circuit diagram showing the configuration of a two-wire dimmer switch according to a second embodiment of the present invention.

Fig. 5 is a circuit diagram showing the configuration of a two-wire dimmer switch according to a third embodiment of the present invention.

Fig. 6 is a circuit diagram showing the configuration of a two-wire dimmer switch according to a fourth embodiment of the present invention.

Fig. 7 is a waveform diagram of each part of a method of controlling a two-wire dimmer switch according to a fifth embodiment of the present invention.

Fig. 8 is a circuit diagram showing the configuration of a two-wire dimmer switch of the first conventional example.

Fig. 9 is a circuit diagram showing the configuration of a two-wire dimmer switch of the second conventional example.

Fig. 10 is a circuit diagram showing the construction of a driving circuit of a general LED bulb.

Figure 11 (a) ~ (b) shows the difference between the load voltage and load current of the bulb and the LED bulb.

Fig. 12 is a state diagram of the self-extinguishing of the bidirectional triode when the load current value of the conventional two-wire dimmer switch is less than the holding current value of the bidirectional triode.

Figure 13 is a state diagram showing the load voltage of the LED bulb caused by the load current of the other two-wire dimmer switch connected to the same AC current.

(First embodiment)

A two-wire dimmer switch according to the first embodiment of the present invention will be described. Fig. 1 is a circuit configuration of a two-wire dimmer switch 1A of the first embodiment. The two-wire dimmer switch 1A is connected in series with the AC power source 2 and the lighting load 3. A switch 5 for turning on and off the illumination load 3 integrated with the dimming variable resistor 4 of the two-wire dimmer switch 1A may be provided, and the switch 5 may be separately provided. In the following description, the switch 5 and the two-wire dimmer switch 1A are separately arranged as an example.

The first connection terminal 1a and the second connection terminal 1b of the two-wire dimmer switch 1A are connected to each other. Stream power supply 2 or lighting load 3 with switch 5. A main switching circuit 10 having a first semiconductor switching element such as a bidirectional triode as the main switching element 11 is connected between the first connection terminal 1a and the second connection terminal 1b. Further, a rectifier circuit 12 connected in parallel with the main switch circuit 10 is connected between the first connection terminal 1a and the second connection terminal 1b, and is connected to the rectifier circuit 12 to secure the internal power of the two-wire dimmer switch 1A. A power supply circuit 13 for the purpose. The power supply circuit 13 includes a first transistor element 13a and a second transistor element 13b connected by Darlington, and a Zener diode 13c and a resistor 13d connected to the base of the second transistor element 13b. The switching circuit is configured, and a constant voltage circuit (such as a three-terminal regulator) 14 and a snubber capacitor 15 for supplying a constant voltage of DC power to a control circuit 16 composed of a microprocessor or the like.

When the switch 5 is turned on, the pulsating flow rectified by the rectifying circuit 12 is input to the power supply circuit 13, and the electric power whose output voltage is dominated by the Zener voltage of the Zener diode 13c is output from the power supply circuit. This power charges the snubber capacitor 15 and is reduced by the constant voltage circuit 14 to a specific voltage (for example, 3 V) and supplied to the control circuit 16. Here, if the resistance value of the resistor 13d of the power supply circuit 13 flows through a high level of the current required to operate the second transistor element 13b, the current flowing to the ground can be passed through the Zener diode 13c. The value is suppressed to be lower, and the power loss can be reduced.

The frequency detecting circuit 17 for detecting the frequency of the AC power source 2 is connected to the DC side output terminal of the rectifier circuit 12, and the specific detection signal output from the frequency detecting circuit 17 is input to the control circuit 16. Further, the DC-side output terminal of the rectifier circuit 12 is connected to a gate for causing a current to flow through the illumination load 3 during a period until the main switching element 11 of the main switch circuit 10 is turned on or when the main switching element 11 is not turned on. The second semiconductor switching element such as a fluid serves as the auxiliary switching circuit 18 of the auxiliary switching element. The control circuit 16 is connected to a dimming amount setting circuit 4 composed of a variable resistor or the like for operation by a user. Further, in the following description, the main switching element is referred to as a bidirectional triode 11 and the auxiliary switching circuit or auxiliary switching element is referred to as a thyristor 18 as necessary.

The frequency detecting circuit 17 is configured to input the pulsating current output from the rectifying circuit 12 to the base of the transistor element 17a, and is controlled by the frequency detecting circuit 17 according to the frequency of the AC power source 2. The circuit 16 inputs a specific detection signal. The control circuit 16 detects the frequency (50 Hz or 60 Hz) of the AC power source 2 from the detection signal of the frequency detecting circuit 17, and estimates the voltage zero crossing point based thereon. Secondly, the gate drive signal is input to the gate terminal of the thyristor 18 according to the frequency of the detection and the estimated voltage zero crossing point. Fig. 2 shows the waveforms of the load voltage, the load current, and the gate drive signal of the 1/2 cycle of the AC power source 2 when the LED bulb is used as the illumination load 3. The start of the gate driving signal (the first timing at which the thyristor 18 is turned on) is determined based on the resistance value of the dimming amount setting circuit (variable resistor) 4, and is searched for in the look-up table previously stored in the control circuit 16. The end of the gate drive signal (the second timing at which the thyristor 18 is non-conducting) is set to advance from the voltage zero crossing point of the AC power source 2 by a specific time Δt (for example, 1 ms). The specific time Δt, for example, the control circuit 16 is sufficient to estimate the time of the next voltage zero crossing point based on the detection signal from the frequency detecting circuit 17.

Next, a specific operation of the two-wire dimmer switch 1A of the first embodiment will be described. When the switch 5 is in the off state, the charge of the snubber capacitor 15 is almost discharged, and the control circuit 16 should be in a state of not functioning. Here, when the switch 5 is turned on, the rectifying circuit 12 outputs, for example, a full-wave rectified pulsating flow. Thereby, the snubber capacitor 15 is charged, and the DC voltage is supplied to the control circuit 16 by the constant voltage circuit 14, and the control circuit 16 is started. At the same time, since the detection signal is input to the control circuit 16 by the frequency detecting circuit 17, the control circuit 16 detects the frequency of the AC power source 2 and estimates its voltage zero crossing point. Next, the control circuit 16 starts the output of the gate drive signal (starts the gate drive signal) in accordance with the first timing of the resistance value of the dimming amount setting circuit (variable resistor) 4. When the gate drive signal is input to the gate terminal of the thyristor 18, the thyristor 18 is turned on and current begins to flow through the illumination load 3. In addition, since the current flowing through the thyristor 18 also flows through the gate electrode of the triac 11 which is the gate voltage threshold of the triac 11 and the on current, the bidirectional triode 11 is turned on, and the load current flows from the thyristor 18 to the bidirectional transistor 11. When the bidirectional triode 11 is turned on, almost no current flows through the rectifying circuit 12, and almost no current flows through the thyristor 18, the power supply circuit 13, and the frequency detecting circuit 17. When no current flows through the power supply circuit 13, the snubber capacitor 15 starts discharging electric power, thereby securing the driving power of the control circuit 16. At this time, the gate drive signal from the control circuit 16 continues to be input to the gate electrode of the thyristor 18, and the thyristor 18 is in an on state.

When the illumination load 3 is an LED bulb, as described above, while the thyristor 18 or the triac 11 is turned on, the load current exhibits an instantaneous large value, however, it becomes small immediately. Next, when the value of the load current is equal to or less than the holding current of the triac 11, the bidirectional triode 11 is self-extinguishing and is non-conducting. However, since the thyristor 18 is turned on, the load current continues to flow through the thyristor 18. Next, the control circuit 16 stops the output of the gate drive signal (stops the gate drive signal) at the second timing of the voltage zero crossing point of the AC power source 2 for a predetermined time Δt. At this stage, almost no load current flows, and even if the thyristor 18 is not turned on, the brightness of the illumination load 3 hardly changes. When the thyristor 18 is non-conducting, the pulsating flow outputted from the rectifying circuit 12 is diverted from the thyristor 18 to the power supply circuit 13 and the frequency detecting circuit 17, and the control circuit 16 can calculate the AC power based on the detection signal from the frequency detecting circuit 17. 2 below a voltage zero crossing point, and based on the estimated voltage zero crossing point, to control the start timing of the output of the next gate driving signal.

In this manner, the two-wire dimmer switch 1A has a period until the main switching element (bidirectional triode) 11 of the main switching circuit 10 is turned on, or when the main switching element 11 is not turned on, so that a current flows through the illumination load 3 For the purpose of the auxiliary switching circuit (brake fluid) 18, the value of the load current is below the holding current of the triac 11 , and even if the triac 11 is non-conducting, the thyristor 18 is turned on, and the load current continues to flow through the thyristor 18 flows. As a result, the brightness of the LED bulb is stable, and almost no flicker or fluctuation can be perceived by the naked eye. Further, even when the maximum value of the load current is equal to or lower than the holding current of the triac 11, the load current can be continuously circulated through the auxiliary switching circuit (thyristor) 18. Moreover, by stopping the gate drive signal input to the gate electrode of the thyristor 18 from the second timing of the voltage zero crossing point of the AC power source 2 for a certain time Δt, it is possible to correctly estimate a voltage zero under the AC power source 2 intersection. Further, as shown in FIG. 3, even if another device connected to the same AC power source 2 is performing an operation, since the load current is continuously supplied through the thyristor 18, the brightness of the illumination load 3 hardly changes. In addition, the load voltage waveform is almost unchanged. Further, the bidirectional transistor 11 may of course also be selected to use a smaller holding current value.

(Second embodiment)

A two-wire dimmer switch according to a second embodiment of the present invention will be described. Fig. 4 is a circuit configuration of a two-wire dimmer switch 1B of the second embodiment. Two-wire dimmer switch 1B, In the two-wire dimmer switch 1A of the above-described first embodiment, an optical bidirectional coupler 20 as a quasi-main switching circuit is added. The secondary side light bidirectional body 21 of the optical two-way triode coupler 20 is connected in parallel to the main switch circuit (bidirectional triode) 11, and the primary side light emitting diode 22 is connected in series to the auxiliary switch unit (brake fluid). 18. The other components are the same. The optical triac 21 is selected such that its holding current value is smaller than the holding current value of the bidirectional triode 11 of the main switching circuit.

Next, the specific operation of the two-wire dimmer switch 1B of the second embodiment will be described focusing on the difference. When the bidirectional triode 11 and the optical triac 21 are arc-extinguished at the voltage zero crossing point of the AC power source 2, a current flows through the rectifying circuit 12, and thereafter, at a specific first timing, the gate driving signal is input to the gate. At the gate terminal of the fluid 18, the thyristor 18 is turned on and the load current flows through the thyristor 18. At this time, the primary side light emitting diode 22 of the optical triac coupler 20 emits light, and the gate terminal of the secondary side optical triode 21 is input with a gate driving signal, and the optical bidirectional body 21 is turned on. When the optical triac 21 is turned on, the load current flows to the optical triac 21 instead. Here, when the load current value is small, and the holding current value of the bidirectional triode 11 of the main switching circuit is less than or equal, the bidirectional triode 11 of the main switching circuit is not turned on, and the load current directly flows through the light of the quasi-main switching circuit. Bidirectional triode 21. On the other hand, when the load current value is large and the holding current value of the bidirectional transistor 11 of the main switching circuit is equal to or higher than the holding current value of the bidirectional transistor 11 of the main switching circuit, the bidirectional transistor 11 of the main switching circuit is turned on, and the load current flows to the bidirectional triode 11 in turn. When the illumination load 3 is an LED bulb, and the value of the load current is equal to or lower than the holding current of the triac 11, the bidirectional triode 11 is self-extinguishing and becomes non-conductive. However, the thyristor 18 is turned on, and the load current temporarily flows to the flow. Brake fluid 18. Next, the primary side light emitting diode 22 of the optical triac coupler 20 emits light, and the secondary side light bidirectional body 21 is turned on, and the load current flows to the optical bidirectional body 21 in turn. The holding current value of the optical triac 21 is as described above, and since it is smaller than the holding current value of the bidirectional transistor 11, the load current can be stably and continuously circulated.

In the two-wire dimmer switch 1B of the second embodiment, the optical bidirectional coupler 20 as a quasi-main switch circuit is added to the two-wire dimmer switch 1A of the first embodiment. A lot of complexity, this part becomes the cause of rising costs. However, even after the bidirectional transistor 11 is non-conducting, the load current flows through the optical bidirectional body 21 on the upstream side (AC side) of the rectifying circuit 12, that is, because the load current does not pass through the diode body. Bridge, not because of the diode bridge And the loss occurred. As a result, the change in the brightness of the LED bulb is very small, and there is almost no flicker or fluctuation that is perceptible to the naked eye.

(Third embodiment)

A two-wire dimmer switch according to a third embodiment of the present invention will be described. Fig. 5 is a circuit configuration of a two-wire dimmer switch 1C of the third embodiment. The two-wire dimmer switch 1C is provided in the two-wire dimmer switch 1A of the first embodiment, and is provided with two auxiliary switch circuits (brake fluids) 18a and 18b, and the anode and the cathode of the thyristor are respectively connected to each other. The AC side of the rectifier circuit 12 and the DC side negative terminal of the rectifier circuit 12. The gate drive signal outputted from the control circuit 16 is diverged by the diodes 25a and 25b, and is input to the gate terminals of the respective thyristors 18a and 18b. That is, one of the two thyristors 18a and 18b is used as an auxiliary switching circuit depending on the polarity of the AC power source 2. Other configurations and operations are the same as those of the two-wire dimmer switch 1A of the first embodiment.

In the two-wire dimmer switch 1C of the third embodiment, a sluice fluid, a resistor, and a capacitor for constituting the auxiliary switch circuit are added as compared with the two-wire dimmer switch 1A of the first embodiment. A lot of complexity, this part becomes the cause of rising costs. However, even after the bidirectional transistor 11 is non-conducting, the load current is reduced by the passage of one of the diodes 1 constituting the rectifying circuit 12, thereby reducing the loss of the portion. When the lighting load 3 is an LED bulb, since the load current value is very small, the loss of one part of the diode is smaller, and the blinking or fluctuation of the LED bulb can be made smaller.

(Fourth embodiment)

A two-wire dimmer switch according to a fourth embodiment of the present invention will be described. Fig. 6 is a circuit configuration of a two-wire dimmer switch 1D of the fourth embodiment. The two-wire dimmer switch 1D is a combination of the two-wire dimmer switch 1B of the second embodiment and the two-wire dimmer switch 1C of the third embodiment, and has a bidirectional light as a quasi-main switch circuit. The triode coupler 20 and two auxiliary switching circuits (brake fluids) 18a and 18b. When the two-wire dimmer switch 1D of the fourth embodiment is the same as the two-wire dimmer switch 1C of the third embodiment, when a load current flows through the thyristor 18a or 18b, one of the rectifier circuits 12 is configured. The diode reduces the loss of this part. Therefore, compared with the two-wire dimmer switch 1B of the second embodiment, the voltage fluctuation of the load current from the thyristor 18a or 18b to the optical triac 21 is small, and the illumination load can be 3 amps. Supply electricity to the ground. As a result, the change in the brightness of the LED bulb is smaller, and there is almost no flicker or fluctuation.

(Fifth Embodiment)

The first to fourth embodiments described above relate to the structure of the two-wire dimmer switch, and the fifth embodiment relates to the control method of any of the two-wire dimmer switches 1A to 1D described above. The two-line dimming switches 1A to 1D and the driving circuit 70 for the LED bulb shown in FIG. 10 each have a circuit configuration in which AC power is converted into DC power and electric power is stored in a snubber capacitor. Therefore, for example, when the switch 5 is turned off for a long time, each of the snubber capacitors should be discharged without power remaining. When the switch 5 is turned on, the two-wire dimmer switches 1A to 1D are activated, and the control circuit 16 outputs a gate drive signal to start supplying power to the illumination load 3. When the illumination load 3 is an LED light bulb, even if power supply is started, the drive circuit 70 does not start, and therefore, the operation and impedance characteristics different from those at the time of normal lighting are exhibited. That is, when power supply to the drive circuit 70 of the LED bulb is started, first, the snubber capacitor 73 is charged. Therefore, when the LED bulb is activated, the capacitance component of the snubber capacitor 73 exhibits a dominant impedance characteristic. Next, when the voltage of the AC power source 2 is high, when the current starts to flow through the driving circuit 70 of the LED bulb, the snubber capacitor 73 is rapidly charged, between the two-wire dimmer switches 1A to 1D and the driving circuit 70 of the LED bulb. A large difference in power factor is produced.

The phase of the voltage applied between the impedances with different power factor differences is different from the phase of the AC power source 2. For example, when the voltage of the AC power source 2 is 100V and the load voltage is -30V, the two-wire dimmer switch 1A The voltage (switching voltage) between the connection terminals 1a and 1b of ~1D is 130V. That is, the voltage zero crossing point of the AC power source 2 is different from the voltage zero crossing point between the switches of the two-wire dimmer switches 1A to 1D. The two-wire dimmer switches 1A to 1D are originally controlled by using the voltage zero crossing point of the AC power source 2 as a reference. However, the control circuit 16 estimates the voltage between the switches by the output of the frequency detecting circuit 17. Intersection and dimming control. Therefore, if the control (output gate drive signal) is executed at a timing different from the voltage zero crossing point of the AC power source 2, the originally stable dimming control may not be realized.

Fig. 7 is a waveform of each part of the control method of the fifth embodiment. Until the start of dimming, pay The phase of the voltage waveform of the stream source 2 coincides with the phase of the voltage waveform between the switches of the two-wire dimmer switches 1A to 1D. The control method according to the fifth embodiment is near the zero crossing point of the voltage between the switches estimated by the output of the frequency detecting circuit 17 at the start of the dimming control of the illumination load 3 (for example, with respect to the zero crossing point of the voltage between the switches) Within ± ms, the initial gate drive signal input by the control circuit 16 to the gate terminal 18 of the auxiliary switch circuit to the gate terminal is output. The timing of outputting the initial gate drive signal can be implemented before the voltage zero crossing point or beyond the voltage zero crossing point. Thereby, the charging of the snubber capacitor 73 of the driving circuit 70 of the LED bulb can be performed from the low level of the voltage of the AC power source 2. Thus, by supplying power to the driving circuit 70 of the LED bulb from the vicinity of the voltage zero crossing point (0V), the impedance of the driving circuit 70 of the two-wire dimmer switch 1A~1D and the LED bulb does not change drastically, and The line dimming switches 1A to 1D and the driving circuit 70 of the LED bulb divide the power of the 1/2 cycle of the AC power source 2. In addition, since a large power factor difference does not occur between the two-wire dimmer switches 1A to 1D and the driving circuit 70 of the LED bulb, stable dimming control can be performed.

Further, as described above, the main switching element is exemplified by a bidirectional triode of a single bidirectional semiconductor switching element. However, the main switching element is not limited thereto, and may be a structure in which a current bidirectionally flows in the same manner as a bidirectional triode. For example, it may be a reverse parallel IGBT (Insulated Gate Bipolar Transistor) or an FET (Field Effect Transistor).

1A‧‧‧2-wire dimmer switch

1a‧‧‧1st connection terminal

1b‧‧‧2nd connection terminal

2‧‧‧AC power supply

3‧‧‧Lighting load

4‧‧‧Dimming amount setting circuit (variable resistor)

5‧‧‧ switch

10‧‧‧Main switch circuit

11‧‧‧Main switching element (bidirectional triode)

12‧‧‧Rectifier circuit

13‧‧‧Power circuit

13a‧‧‧1st transistor component

13b‧‧‧2nd transistor component

13c‧‧‧Zina diode

13d‧‧‧resist

14‧‧‧ Constant voltage circuit

15‧‧‧ snubber capacitor

16‧‧‧Control circuit

17‧‧‧ Frequency detection circuit

17a‧‧‧Optoelectronic components

18‧‧‧Auxiliary switch circuit (auxiliary switching element, thyristor)

Claims (6)

A two-wire dimmer switch connected in series to an AC power supply and a lighting load, comprising: a first connection terminal and a second connection terminal, wherein AC power is input; and a main switch circuit is coupled to the first connection terminal and the first Between the two connection terminals, the first semiconductor switching element is used as the main switching element; the rectifier circuit is connected between the first connection terminal and the second connection terminal; and the power supply circuit is connected to the DC side of the rectifier circuit for The internal power supply of the two-wire dimmer switch is ensured; the frequency detecting circuit is connected to the DC side of the rectifier circuit to output a specific detection signal for detecting the frequency of the AC power source; the auxiliary switching circuit is coupled to the DC of the rectifier circuit On the side or the AC side, the second semiconductor switching element is used as an auxiliary switching element, and when the main switching element is not turned on, a load current flows, and a gate driving signal for turning on the main switching element or other semiconductor switching elements is output. a dimming amount setting circuit operated by a user to set a dimming amount for adjusting the brightness of the lighting load; and a control circuit And detecting the frequency of the AC power source according to the detection signal outputted by the frequency detecting circuit, estimating a voltage zero crossing point of the AC power source, and adjusting a dimming amount according to the dimming amount setting circuit, and The first timing determined by the estimated voltage zero crossing point, the output of the driving signal for turning on the auxiliary switching circuit is started, and the voltage zero crossing point is estimated to be earlier than the estimated voltage zero crossing point before the specific time The second timing stops the output of the drive signal. The two-wire dimmer switch according to claim 1, wherein the second-line dimmer switch further includes a quasi-main switch circuit that is turned on by the gate drive signal output from the auxiliary switch circuit, in the auxiliary switch circuit. After the conduction, when the main switching element is not turned on, the load current flows, and a driving signal for turning on the main switching element is output. The two-wire dimmer switch according to claim 1 or 2, wherein the main switching element is a bidirectional triode, and the auxiliary switching circuit is a thyristor connected to a DC side of the rectifying circuit. Auxiliary Switching element. The two-wire dimmer switch according to claim 1 or 2, wherein the main switching element is a bidirectional triode, and the auxiliary switching circuit is connected to an alternating current side of the rectifying circuit, and The two thyristors of the alternating current source are alternately turned on as auxiliary switching elements. For example, the second-line dimmer switch described in item 2 of the patent application, item 3 of item 2, or item 4 of item 2, wherein: the quasi-main switch circuit is optically bidirectional The triode coupler is used as a switching element, and the optical bidirectional triode system on the secondary side of the optical triac coupler is connected in parallel to the main switching element, and one of the terminals is connected to the gate terminal of the main switching element The light-emitting diode system on the primary side of the optical triac coupler is connected in series to the auxiliary switching circuit, and the holding current value of the optical bidirectional triode is smaller than the holding current value of the bidirectional triode. The two-wire dimmer switch according to any one of claims 1 to 5, wherein: the control circuit starts the dimming control of the illumination load, and the estimated voltage is near zero crossing point At a particular timing, the output is used to turn on the initial drive signal of the auxiliary switch circuit.