JP2007174577A - Two-wire electronic switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-wire electronic switch capable of extending its load adaptive range by reducing a range where an operation of a load is unstable. <P>SOLUTION: A gate current of the triac (load switching section) 1 decreases at a high temperature and increases at a low temperature. A triac drive section 8 includes circuit paths different from polarities of a gate current. When a control signal of a control section 3 goes to a high level, a third power supply section 6 is turned on to supply power to a first power supply section 4. Thereafter, when a cathode level of a Zener diode 72 is higher than a Zener voltage, a thyristor 70 is turned on by a gate current from a thyristor drive section 71 and a load current flows from a rectifier section 2 to the thyristor 70. Thereafter, the triac drive section 8 sets the circuit path in response to the polarity of the gate current in a way of making a turn-on timing of the triac 1 constant to bring the triac 1 into an on state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a two-wire electronic switch for turning on and off the power supply from an AC power supply to a load, and it is necessary to secure an operating power supply by itself.

  Conventionally, as a switch to turn on / off the power supply from the AC power supply to the load, a non-contact switching element such as a thyristor or a triac is inserted into the power supply path from the AC power supply to the load as a load switching unit with the digitization of the wiring equipment. However, there is provided a type (first conventional switch) that electrically opens and closes (turns on and off) the contactless switching element using an electronic circuit. The first conventional switch needs to secure its own operating power supply (circuit power supply) because the electronic circuit drives the non-contact switching element when a person operates the operation unit (operation switch). Therefore, the first conventional switch has a configuration in which wiring is performed by three lines or four lines.

  However, from the viewpoint of reduced wiring, when a two-wire wiring is a general wiring device, the first conventional switch cannot individually draw in the power source wire when connected to the AC power source and the load by the two wires. As a result, securing a self-operating power supply became a problem.

  In order to solve the above problem, a two-wire electronic switch (2 wire electronic switch that enables two-wire wiring in a state in which a contactless switching element is used as a load switching unit while being connected in series with an AC power source and a load. A second conventional switch) has been proposed. A configuration almost similar to that of the second conventional switch is disclosed in Patent Document 1.

  The operation of the second conventional switch will be described with reference to FIG. FIG. 4 is a circuit diagram of a second conventional switch. In the second conventional switch 9, a triac 90 as a load switching unit is connected in series with the AC power source AC and the load L. First, when the control signal from the control output terminal 910 of the control unit 91 becomes low level, the third power supply unit 92 is turned off. At this time, the second power supply unit 93 supplies power to the first power supply unit 94. In this state, the gate current (drive signal) of a magnitude necessary to turn on the triac 90 does not flow through the gate (drive signal input terminal) of the triac 90, so the triac 90 is turned off (opened). The power supply from the AC power supply AC to the load L is cut off.

On the other hand, when the control signal from the control output terminal 910 of the control unit 91 becomes a high level, the third power supply unit 92 is turned on. As a result, the third power supply unit 92 supplies power to the first power supply unit 94. At this time, when the charging of the first power supply unit 94 is completed, a current flows from the charging completion detection unit 920 to the auxiliary opening / closing unit 95, and the auxiliary opening / closing unit 95 is turned on (closed). When the auxiliary opening / closing unit 95 is turned on, a current having a magnitude necessary for turning on the triac 90 flows to the triac drive unit 96, and a gate current flows from the triac drive unit 96 to the triac 90. Thus, the triac 90 is turned on (closed), and power is supplied from the AC power supply AC to the load L.
JP 2001-227804 A (pages 2 to 5 and FIG. 7)

  However, the second conventional switch 9 has a load switching unit (triac 90) having a dependency on the polarity of the driving signal in the amplitude value of the driving signal when the electrical switching between both ends is switched. There has been a problem that the sensitivity of the opening / closing part differs with respect to the polarity of the drive signal. More specifically, first, when the load current is small, as shown in FIG. 5A, the load switching unit is turned on with the polarity on the high sensitivity side of the drive signal. On the other hand, when the load current is large, as shown in FIG. 5B, the load switching unit is turned on with both polarities on the high sensitivity side and the low sensitivity side of the drive signal. At this time, the turn-on timing differs between the polarity on the high sensitivity side and the polarity on the low sensitivity side of the drive signal. That is, near the amplitude value of the drive signal at which the load switching unit is turned on, the load switching unit is turned on or not turned on. When such a state where the sensitivity difference of the load opening / closing part with respect to the polarity of the drive signal is large occurs in a long cycle, the condition range in which the above problem occurs is expanded, and the operation of the load becomes unstable. For example, when an incandescent bulb is used as a load, the emitted light appears to fluctuate. As a result, restrictions on the load suitable for the two-wire electronic switch and restrictions on the operating voltage range become severe.

  The present invention has been made in view of the above points, and an object of the present invention is to reduce the range in which the operation of the load becomes unstable, and to increase the load compatible range 2. It is to provide a wire electronic switch.

  The invention according to claim 1 is a two-wire electronic switch that is connected to an AC power source and a load by two wires and secures its own operating power source based on the AC power from the AC power source. A load switching unit that is inserted in the power supply path to the load and has a dependency on the polarity of the drive signal when the electrical switching between both ends is switched, and operates with power based on the AC power And a control unit that outputs a control signal for controlling power supply from the AC power source to the load by switching the electrical switching of the load switching unit, and the AC power source to the load based on the control signal. Drive that controls the drive signal and outputs it to the load switching unit so that the switching timing of the electrical switching of the load switching unit becomes constant with respect to the polarity of the drive signal when performing the power supply Characterized in that it comprises and.

  In this configuration, since the drive signal can be controlled so that the switching timing of the electrical opening / closing of the load opening / closing unit is constant with respect to the polarity of the drive signal, the range in which the operation of the load becomes unstable can be reduced. And the range of load adaptation can be expanded.

  According to a second aspect of the present invention, in the first aspect of the present invention, the drive unit has different impedances for each polarity of the drive signal. In this configuration, the switching timing of the electrical switching of the load switching unit can be made constant with respect to the polarity of the drive signal with an inexpensive configuration.

  The invention according to claim 3 is the invention according to claim 2, wherein at least one of the impedances is connected to a drive signal input end of the load switching unit at one end and the both ends of the load switching unit at the other end. And a temperature-sensitive resistor that controls the drive signal so that the switching timing of the electrical switching of the load switching unit is constant with respect to a temperature change of the load switching unit. To do. In this configuration, by using the temperature sensitive resistor, the switching timing of the electrical switching of the load switching unit can be made constant with respect to the temperature change of the load switching unit with a small size and low cost.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the first power source unit serving as an operation power source of the control unit and the load switching unit are in an open state, and the AC When the power supply from the power source to the load is stopped, based on the control signal, a second power source unit that supplies power converted from the AC power to the first power source unit, A third power supply unit that supplies power converted from alternating current power to the first power supply unit, and is electrically connected in series to the drive unit, and the third power supply unit to the first power supply unit When the input voltage of the first power supply unit becomes higher than a predetermined voltage value when power is supplied, the drive unit is controlled to control the drive signal by closing the load. Auxiliary opening / closing unit that outputs to the opening / closing unit is provided.In this configuration, the first power supply unit, the second power supply unit, the third power supply unit, and the auxiliary opening / closing unit can reliably supply power to the control unit, and can reliably supply a drive signal to the drive unit. Can be controlled.

  According to the present invention, the range where the operation of the load becomes unstable can be reduced, and the load compatible range can be expanded.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a circuit diagram of a two-wire electronic switch according to the first embodiment.

  First, the basic configuration of the first embodiment will be described. The two-wire electronic switch A according to the first embodiment secures its own operating power source based on the AC power from the AC power source AC. As shown in FIG. 1, the triac 1, the rectifier 2, and the control Unit 3, first power supply unit 4, second power supply unit 5, third power supply unit 6, auxiliary opening / closing unit 7, and triac drive unit 8, and in series with AC power supply AC and load L Are connected with two wires. The AC power supply AC is, for example, a commercial power supply of 100V. The load L is, for example, a lighting device including a fluorescent lamp or an incandescent bulb, a ventilation fan, or the like.

  The triac 1 is a load switching unit that is formed of a semiconductor such as silicon and switches electrical switching between the two terminals 10 and 11 in accordance with a gate current (drive signal). The TRIAC 1 is connected in series with an AC power source AC and a load L via terminals 12 and 13 and a filter inductor 14. The triac 1 and the inductor 14 are connected in parallel with the surge absorbing element 15 and the filter capacitor 16, respectively. In the first embodiment, when the triac 1 is turned on (closed), the circuit is made up of the AC power supply AC, the triac 1, the inductor 14, and the load L, and power is supplied to the load L so that the load L operates. On the other hand, when the triac 1 is turned off (opened), power is not supplied to the load L, and the operation of the load L is stopped.

  By the way, the triac 1 has a dependency on the polarity of the gate current in the amplitude value of the gate current when the electrical switching between the two terminals 10 and 11 is switched. When a gate current of one polarity flows, the triac 1 is turned on with an amplitude value smaller than the gate current of the other polarity and is turned on. From the above, the sensitivity of the triac 1 varies depending on the polarity, and the sensitivity is high in one polarity of the gate current, and the triac 1 is turned on with a small gate current or a low gate voltage. On the other hand, the sensitivity of the other polarity of the gate current is low, and a large gate current and a high gate voltage are required to turn on.

  The rectification unit 2 is a diode bridge composed of four diodes, and is connected to the AC power supply AC and the load L via terminals 12 and 13 at the input end, and the second power supply unit 5 and the third power supply unit at the output end. 6 and the auxiliary opening / closing part 7. The rectifying unit 2 performs full-wave rectification on the AC power from the AC power supply AC, and outputs the full-wave rectified power to the second power supply unit 5, the third power supply unit 6, and the auxiliary opening / closing unit 7.

  The control unit 3 is a microcomputer that outputs a control signal for switching electrical opening / closing of the triac 1 from the control output terminal 30 to the third power supply unit 6 by, for example, a human operation. The control unit 3 operates with electric power from the first power supply unit 4. In addition, the control unit 3 is provided with an operation unit (operation switch) (not shown) such as a tact switch, which is operated by a person, and the control signal is output every time the operation unit is operated. 3 to the power supply unit 6. The control signal is a binary signal having a high level and a low level. The control unit 3 outputs a high level control signal when the triac 1 is turned on, and when the triac 1 is turned off. Outputs a low level control signal. Thereby, the control unit 3 controls power supply from the AC power supply AC to the load L.

  The first power supply unit 4 is an operation power supply for the control unit 3, and includes a buffer capacitor 40, a three-terminal regulator 41, a capacitor 42, and a capacitor 43 connected in parallel from the input end side. The input end is connected to the second power supply unit 5 and the third power supply unit 6, and the output end is connected to the input end of the control unit 3. The buffer capacitor 40 is charged with power from the second power supply unit 5 and the third power supply unit 6 and smoothed by removing ripple components. The three-terminal regulator 41 stabilizes the direct-current voltage of the buffer capacitor 40 to, for example, 3V. From the above, the first power supply unit 4 supplies stable power to the control unit 3.

  The second power supply unit 5 includes, in order from the input end side, a current-limiting resistor 50, an NPN transistor 51, and a resistor 52 connected in series, and is connected to the output end of the rectifying unit 2 at the input end. In addition, the first power supply unit 4 is connected on the output end side. The second power supply unit 5 includes a bias resistor 53 connected between the base and collector of the transistor 51, and a Zener diode 54 whose cathode is connected to the base of the transistor 51. The base of the transistor 51 is grounded via a Zener diode 54. The impedance conversion of the second power supply unit 5 is performed according to the on state and the off state of the transistor 51. The second power supply unit 5 supplies AC power from the AC power supply AC via the rectifying unit 2 when the triac 1 is turned off and power supply from the AC power supply AC to the load L is stopped. The power is received as full-wave rectified power, is converted into power whose size is regulated by the Zener diode 54, and the converted power is supplied to the first power supply unit 4. At this time, the load current in the two-wire electronic switch A is divided into a current flowing through the first power supply unit 4 and a current flowing through the Zener diode 54, both of which are finally connected to the rectifying unit via the ground. 2 and returns to the AC power source AC via the load L. The load current at this time is large enough to prevent the load L from malfunctioning. Further, the current consumption of the control unit 3 is kept low, and the impedance of the second power supply unit 5 is kept high.

  The third power supply unit 6 includes, in order from the input end side, a PNP transistor 60 and a diode 61 connected in series. The third power supply unit 6 is connected to the output end of the rectifying unit 2 at the input end and the first at the output end. Is connected to the power supply unit 4 of That is, the third power supply unit 6 is connected in parallel with the second power supply unit 5. The third power supply unit 6 includes a resistor 62 and a capacitor 63 connected between the base and emitter of the transistor 60, and a resistor 64 and an NPN transistor 65 connected to the base of the transistor 60. Further, the third power supply unit 6 includes a resistor 66 connected between the base and emitter of the transistor 65. The transistor 65 has an emitter grounded and a base connected to the control output terminal 30 of the control unit 3. The transistor 65 controls the on / off state of the transistor 60. The third power source unit 6 receives AC power from the AC power source AC as full-wave rectified power via the rectifying unit 2 based on a control signal from the control unit 3, and receives the power from the first power source AC. The power is supplied to the power supply unit 4. A specific procedure will be described. When a high-level control signal is received from the control unit 3, the transistor 65 is turned on. Accordingly, the transistor 60 is turned on. At this time, the impedance of the two-wire electronic switch A decreases. Thereafter, the third power supply unit 6 supplies power to the first power supply unit 4. On the other hand, when a low-level control signal is received from the control unit 3, the transistor 65 is turned off. Accordingly, the transistor 60 is also turned off. As a result, the third power supply unit 6 stops supplying power to the first power supply unit 4.

  The auxiliary opening / closing unit 7 includes a thyristor 70 and a thyristor driving unit 71. The thyristor 70 is connected to the output terminal of the rectifying unit 2 and is also connected to the input terminals of the second power supply unit 5 and the third power supply unit 6. On the other hand, the thyristor driving unit 71 includes a resistor 710 and a capacitor 711 connected in parallel, one end connected to the gate of the thyristor 70 and the Zener diode 72, and the other end connected to the cathode of the thyristor 70. The zener diode 72 is connected to the DC voltage of the buffer capacitor 40 of the first power supply unit 4 when the power is supplied from the third power supply unit 6 to the first power supply unit 4. When the input voltage becomes higher and the cathode potential becomes higher than the zener voltage, the charging completion detection unit detects that the charging of the first power supply unit 4 is completed by flowing a reverse current to the thyristor driving unit 71. . When a reverse current flows from the Zener diode 72, the thyristor driving unit 71 causes a gate current of a magnitude necessary to turn on the thyristor 70 to flow through the thyristor 70 for a certain period. Thereby, the load current flowing from the rectifying unit 2 to the third power supply unit 6 flows from the rectifying unit 2 to the thyristor 70, and the auxiliary opening / closing unit 7 is necessary to turn on the triac 1 with respect to the triac driving unit 8. Control is performed so that a large amount of gate current flows through the triac 1.

  The triac drive unit 8 includes a series circuit of a resistor 80 and a diode 81 and a resistor 82 connected in parallel, and is connected to the gate (drive signal input terminal) of the triac 1 at one end and the terminal of the triac 1 at the other end. 11 is connected. Further, the triac drive unit 8 is connected in series with the thyristor 70 of the auxiliary opening / closing unit 7 via the rectification unit 2. When the thyristor 70 is turned on (closed), the current flowing through the triac drive unit 8 increases, and a gate current having a magnitude necessary for turning on the triac 1 is supplied to the gate of the triac 1.

  Here, the current flowing through the triac drive unit 8 is adjusted for each polarity by flowing through the parallel circuit of the resistor 80 and the resistor 82 in one polarity and flowing only the resistor 82 in the other polarity. That is, the triac drive unit 8 adjusts the gate current injected into the gate of the triac 1 so that the load current that flows when the triac 1 is turned on is stable with respect to the polarity of the gate current of the triac 1. Specifically, the triac drive unit 8 is configured with different impedances with respect to the polarity of the gate current generated at the gate. Specifically, a diode 81 is used as an element for determining polarity, and resistors 80 and 82 are used as impedance elements, and a bypass path is provided only for the polarity of one gate current. In such a configuration, the triac drive unit 8 reduces the gate current by increasing the current flowing through the triac drive unit 8 in the polarity where the sensitivity of the triac 1 is high. On the contrary, in the polarity where the sensitivity of the triac 1 is low, the gate current is increased by reducing the current flowing through the triac drive unit 8. Such a triac drive unit 8 is configured so that when the power is supplied from the AC power supply AC to the load L based on the control signal, the turn-on timing of the triac 1 is constant with respect to the polarity of the gate current. The current is controlled. Thereby, even if the triac 1 becomes highly sensitive, the triac 1 is turned on and turned on to prevent the load current in the two-wire electronic switch A from becoming too small.

  Next, the operation of the two-wire electronic switch A of Embodiment 1 will be described. First, an operation in a state where the power supply from the AC power supply AC to the load L is not performed (off state) will be described. When the control signal of the control unit 3 becomes low level, the transistor 65 and the transistor 60 of the third power supply unit 6 are turned off. On the other hand, the second power supply unit 5 supplies power to the first power supply unit 4. As a result, the first power supply unit 4 serves as an operating power supply for the control unit 3. In this state, since the gate current of a magnitude necessary for turning on the triac 1 does not flow through the gate of the triac 1, the triac 1 is turned off and operates from the AC power supply AC to the load L. Insufficient power is supplied.

  Subsequently, an operation in a state where the power supply from the AC power supply AC to the load L is performed (on state) will be described. When the control signal of the control unit 3 becomes high level, the transistor 65 and the transistor 60 are turned on, and the third power supply unit 6 supplies power to the first power supply unit 4. As a result, the first power supply unit 4 serves as an operating power supply for the control unit 3. On the other hand, when the input voltage of the first power supply unit 4 increases and the cathode potential of the Zener diode 72 becomes higher than the Zener voltage, the Zener diode 72 causes a reverse current to flow to the thyristor driving unit 71. After that, the thyristor driving unit 71 passes a gate current of a magnitude necessary for turning on the thyristor 70 to the thyristor 70, and the thyristor 70 is turned on. As a result, the load current flowing from the rectifying unit 2 to the third power supply unit 6 flows from the rectifying unit 2 to the thyristor 70. After that, the triac drive unit 8 sets a circuit path according to the polarity of the gate current so that the turn-on timing of the triac 1 is constant. The triac drive unit 8 causes a gate current of a magnitude necessary for turning on the triac 1 to flow through the gate of the triac 1, and the triac 1 is turned on. As described above, power is supplied from the AC power supply AC to the load L.

  Here, when the TRIAC 1 is turned on, a load current flows through the TRIAC 1. However, when the zero cross point is reached, the arc is turned off and turned off. When the triac 1 is turned off, a load current flows again from the rectifying unit 2 to the first power source unit 4 via the third power source unit 6, and an operating power source for the two-wire electronic switch A is secured, and a thyristor 70 is provided. And the operation to turn on the triac 1 is performed. That is, the operation of securing the operating power supply is performed every half cycle of the AC power from the AC power supply AC.

  As described above, according to the first embodiment, since the gate current can be controlled so that the switching timing of the electrical opening / closing of the triac 1 is constant with respect to the polarity of the gate current, the operation of the load L becomes unstable. The range can be reduced, and the load compatible range can be expanded. Further, by providing the triac drive unit 8 with the impedance element, the switching timing of the electrical opening and closing of the triac 1 can be made constant with respect to the polarity of the gate current with an inexpensive configuration. Furthermore, the first power supply unit 4, the second power supply unit 5, and the third power supply unit 6 can reliably supply power based on AC power from the AC power supply AC to the control unit 3. The section 7 can reliably switch the triac 10 of the load switching unit 1 to the off state.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a main part circuit diagram of the two-wire electronic switch according to the second embodiment. Note that a, b, c, and d in FIG. 2 are connected to the terminal 12, the inductor 14, and the rectifying unit 2 at a, b, c, and d in FIG. 1.

  The two-wire electronic switch B according to the second embodiment is similar to the two-wire electronic switch A according to the first embodiment (see FIG. 1). The triac 1, the rectifier 2, the controller 3, and the first power supply 4, the second power supply unit 5, the third power supply unit 6, and the auxiliary opening / closing unit 7, but the following characteristic portions that are not included in the two-wire electronic switch A of the first embodiment are as follows. is there.

  The two-wire electronic switch B of the second embodiment includes a triac drive unit 8a as shown in FIG. 2 instead of the triac drive unit 8 of the first embodiment. The triac drive unit 8a includes a series circuit of a resistor 80 and a diode 81 and a series circuit of a resistor 82 and a diode 83 connected in parallel. The triac drive unit 8a is the same as the triac drive unit 8 (see FIG. 1) of the first embodiment except for the points described above.

  As described above, even in the second embodiment, the same effect as in the first embodiment can be obtained.

(Embodiment 3)
Embodiment 3 of the present invention will be described. FIG. 3 shows the temperature dependence of the triac in the two-wire electronic switch of the third embodiment, where (a) shows a measurement circuit diagram, (b) shows a gate current, and (c) shows a gate voltage. is there.

  The two-wire electronic switch according to the third embodiment is similar to the two-wire electronic switch A according to the first embodiment (see FIG. 1). The triac 1, the rectifier 2, the controller 3, and the first power supply 4 The second power supply unit 5, the third power supply unit 6, and the auxiliary opening / closing unit 7 are provided. However, the two-wire electronic switch A of the first embodiment has the following characteristic portions. .

The triac 1 of the third embodiment has temperature dependency on the amplitude values of the gate current and the gate voltage when the electrical switching between the two terminals 10 and 11 is switched. Figure 3 using a measuring circuit, such as (a), the electrical opening and closing of the triac 1 to measure the gate current I _GT and the gate voltage V _GT switched, the gate current I _GT, as shown in FIG. 3 (b) , It becomes smaller at higher temperatures and larger at lower temperatures. Further, as shown in FIG. 3C, the gate voltage _VGT is lowered when the temperature is high, and is high when the temperature is low. From the above, the sensitivity of the triac 1 of Embodiment 3 increases as the temperature increases. That is, it turns on with a small gate current or a low gate voltage. On the other hand, when the temperature is lowered, the sensitivity is lowered, and a large gate current and a high gate voltage are required for turning on. FIG. 3B shows values normalized by the gate current at 25 ° C., and FIG. 3C shows values normalized by the gate voltage at 25 ° C.

  Further, the triac drive unit according to the third embodiment includes a temperature-sensitive resistor instead of the resistors 80 and 82 of the triac drive unit 8 according to the first embodiment. The temperature-sensitive resistor of the third embodiment is connected to the gate of the triac 1 at one end and to the terminal 11 of the triac 1 at the other end. The temperature-sensitive resistor is, for example, an NTC thermistor, which monitors the temperature increase of the triac 1 and changes its resistance value according to the temperature of the triac 1. Specifically, the temperature-sensitive resistance decreases as the temperature of the triac 1 increases and increases the flowing current. On the contrary, when the temperature of the TRIAC 1 decreases, the resistance value increases and the flowing current is reduced. Such a temperature-sensitive resistor changes the gate current so that the turn-on timing of the triac 1 is constant with respect to the temperature change of the triac 1. This prevents the load current in the two-wire electronic switch from being too small when the triac 1 is turned on and turned on even if the triac 1 becomes highly sensitive due to temperature rise. The temperature-sensitive resistance of the third embodiment is the same as the resistors 80 and 82 (see FIG. 1) of the first embodiment except for the points described above.

  Next, the operation of the two-wire electronic switch of Embodiment 3 will be described. The operation in a state where the power supply from the AC power supply AC to the load L is not performed (off state) is the same as that in the first embodiment. Subsequently, an operation in a state where the power supply from the AC power supply AC to the load L is performed (on state) will be described. When the control signal of the control unit 3 becomes high level, as in the first embodiment, when the cathode potential of the Zener diode 72 becomes higher than the Zener voltage, the Zener diode 72 causes a reverse current to flow to the thyristor driving unit 71. Thereafter, the thyristor driving unit 71 passes a gate current to the thyristor 70, and the thyristor 70 is turned on. Then, the resistance value corresponding to the temperature of the triac is set for the temperature-sensitive resistance so that the turn-on timing of the triac is constant. Due to the temperature sensitive resistance, a gate current flows to the gate of the triac, and the triac is turned on.

  As described above, according to the third embodiment, even when the temperature increase of the triac 1 becomes large, the temperature sensitive resistance is set so that the switching timing of the electrical opening and closing of the triac 1 is constant with respect to the temperature change of the triac 1. Since the resistance value of the triac 1 can be changed, it is possible to reduce that the triac 1 is turned on and turned on before securing the operating power of the two-wire electronic switch, and the operating power is stably secured. can do. In addition, by using the temperature sensitive resistor, the switching timing of the electrical opening and closing of the triac 1 can be made constant with respect to the temperature with a small size and low cost.

  As a modification of the first to third embodiments, the load opening / closing unit may include a thyristor instead of the triac. Even with such a configuration, the same effects as those of the first embodiment can be obtained.

  As another modification of the first to third embodiments, when the triac is turned on and when the triac is turned off, the control unit outputs a pulsed control signal to the third power supply unit, The third power supply unit may supply power to the first power supply unit based on the control signal. Even with such a configuration, the same effects as those of the first embodiment can be obtained.

1 is a circuit diagram of a two-wire electronic switch according to a first embodiment of the present invention. It is a principal part circuit diagram of the 2 wire type electronic switch of Embodiment 2 by this invention. FIG. 4 is a temperature dependence of triac in the two-wire electronic switch according to the third embodiment of the present invention, where (a) is a measurement circuit diagram, (b) is a diagram showing a gate current, and (c) is a diagram showing a gate voltage. is there. It is a circuit diagram of the conventional 2-wire type electronic switch. FIG. 3A is a diagram showing a turn-off state when the load current is small, and FIG. 3B is a diagram showing a turn-off state when the load current is large. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Triac 2 Rectification part 3 Control part 4 1st power supply part 6 3rd power supply part 70 Thyristor 71 Thyristor drive part 72 Zener diode 8 Triac drive part

Claims (4)

A two-wire electronic switch that is connected to an AC power source and a load with two wires and secures its own operating power source based on the AC power from the AC power source,
A load switching unit that is inserted into a power supply path from the AC power source to the load and has a dependency on the polarity of the drive signal to the amplitude value of the drive signal when electrical switching between both ends is switched;
A controller that operates with power based on the AC power, and outputs a control signal that controls power supply from the AC power supply to the load by switching the electrical switching of the load switching unit;
When performing the power supply from the AC power source to the load based on the control signal, the switching timing of the electrical switching of the load switching unit is constant with respect to the polarity of the drive signal. A two-wire electronic switch, comprising: a driving unit that controls a driving signal and outputs the driving signal to the load switching unit.   The switch according to claim 1, wherein the driving unit has different impedances for each polarity of the driving signal.   At least one of the impedances is connected to the drive signal input end of the load switching unit at one end and connected to one of the both ends of the load switching unit at the other end, and the switching timing of the electrical switching of the load switching unit The two-wire electronic switch according to claim 2, wherein the two-wire electronic switch is a temperature-sensitive resistor that controls the drive signal so that is constant with respect to a temperature change of the load switching unit. A first power supply unit serving as an operation power supply for the control unit;
A second power source configured to supply power converted from the AC power to the first power source when the load switching unit is in an open state and the power supply from the AC power source to the load is stopped. A power supply,
A third power supply unit that supplies power converted from the AC power to the first power supply unit based on the control signal;
The input voltage of the first power supply unit is a predetermined voltage when the first power supply unit is electrically connected in series with the drive unit and power is supplied from the third power supply unit to the first power supply unit. An auxiliary opening / closing part that causes the driving part to control the drive signal to output to the load opening / closing part by being in a closed state when higher than a value is provided. The two-wire electronic switch described.

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