WO2013132811A1

WO2013132811A1 - Two-wire load control device

Info

Publication number: WO2013132811A1
Application number: PCT/JP2013/001288
Authority: WO
Inventors: 齋藤　裕; 東浜　弘忠; 陽子谷利; 豊田　一郎
Original assignee: パナソニック株式会社
Priority date: 2012-03-05
Filing date: 2013-03-04
Publication date: 2013-09-12
Also published as: TW201346480A; JP5903673B2; TWI488019B; JP2013182856A; CN104145531A

Abstract

Provided is a two-wire load control device that uses a relay-type switch element, wherein, if a bulb burns out and so on, bulb replacement can be carried out with the relay-type switch element having been reliably switched to a non-conductive state. The two-wire load control device is equipped with: a series circuit of a relay-type switch element (12) and a current converter (13) connected between an alternating-current power source (2) and a load (3); an ON power source unit (17) that is connected to a secondary side of the current converter (13), and outputs direct-current power when the relay-type switch element (12) is in a conductive state; an ON power-source power detection unit (31) that detects a physical quantity indicating direct-current power that is output from the ON power source unit (17); and a control unit (20) that controls the conduction and non-conduction of the relay-type switch element (12). If it is determined that the direct-current power output from the ON power source unit (17) is less than a predetermined threshold power due to a bulb burning out for example, the relay-type switch element (12) is switched to a non-conductive state.

Description

Two-wire load control device

The present invention relates to a two-wire load control device for controlling on and off of a load such as a lighting device.

Conventionally, a load control device using a semiconductor switching element such as a triac is known. Among the load control devices using such semiconductor switch elements, the two-wire load control device is connected in series between the AC power source and the load, so that the wiring work is simple. On the other hand, it is necessary to secure a power source for driving the semiconductor switch element and the control circuit (CPU or the like) even when the load is turned off. Therefore, even when a rectifier circuit is connected in parallel to the semiconductor switch element and the load is turned off, a weak current that does not actually turn on or malfunction is passed through the load, and the buffered capacitor is charged with the rectified current, The power supply when the load is off (off power supply unit) is secured. Further, even when the load is on, a power source (on power supply unit) when the load is on is secured by using the current rectified by the rectifier circuit (see, for example, JP 2008-97535A).

The off power supply unit is a constant voltage circuit (bootstrap circuit) composed of, for example, a resistor that limits current, a Zener diode (constant voltage diode) that clamps voltage, and a transistor, and is full-wave rectified by a rectifier circuit. The pulsating flow is input. Part of the current output from the off power supply unit flows to the control unit and is used to drive the CPU and the like. The remaining current charges the buffer capacitor. When the voltage of the pulsating current rectified by the rectifier circuit is lower than the Zener voltage, the buffer capacitor is a power source, and therefore the buffer capacitor is repeatedly charged and discharged. Thus, even when the load is originally off as described above, a current flows through the load via the Zener diode and the rectifier circuit.

On the other hand, in order to turn on the load, for example, a drive signal is input from the control unit to the gate of the semiconductor switch element to turn on the semiconductor switch element. As a result, the rectified voltage of the rectifier circuit becomes substantially zero, and the on power supply unit and the off power supply unit become non-conductive. While the on power supply unit and the off power supply unit are non-conducting, power is supplied to the control unit from the buffer capacitor, and the terminal voltage of the buffer capacitor gradually decreases. When the current of the AC power supply becomes zero, the semiconductor switch element becomes non-conductive due to self-extinguishing, and a voltage is generated in the rectifier circuit. Thus, the self-circuit power supply securing of the load control device and the conduction / non-conduction operation of the semiconductor switch element are repeated every half cycle of the alternating current.

Semiconductor switch elements such as triac require relatively little power to control their conduction and non-conduction. Therefore, the semiconductor switch element can be driven by the electric power charged in the buffer capacitor as described above. On the other hand, the load current that can flow through the semiconductor switch element is relatively small, so it is suitable for loads that require large currents, such as lighting devices with many incandescent bulbs and multiple lighting devices connected in series or in parallel. Not. Therefore, in order to control on and off of a load that requires a large current, a switch element (hereinafter referred to as a relay type switch element) having a mechanically driven contact, such as a latch relay, is used. Conceivable. However, in order to turn on and off such a mechanical contact, for example, an electromagnet device or the like needs to be driven, and a large amount of power is required.

By the way, not only incandescent bulbs but also bulb-type fluorescent lamps and LED bulbs have a lifetime, and so-called bulb breaks such as filament breakage and lighting circuit failure occur. Therefore, in a two-wire load control device using a relay type switch element, when a ball break occurs or an LED bulb is used, a drive signal is not obtained until sufficient power can be secured to drive the electromagnet device. Is output, the electromagnet device is not driven, the relay switch element is not switched from the conductive state to the non-conductive state, or vice versa, and the load is not turned on / off. When the user replaces the bulb that has broken the bulb while the load is turned on in this way, the voltage may be applied to the terminal of the luminaire, and the user may get an electric shock.

The present invention has been made in order to solve the above-described problems of the conventional example, and in a two-wire load control device using a relay type switch element, when a bulb break or the like occurs, a relay type is surely provided. It is an object of the present invention to provide a two-wire load control device that can replace a light bulb in a state where a switch element is switched to non-conduction.

In order to achieve the above object, a two-wire load control device according to the present invention includes:
Two input terminals respectively connected to an AC power source and a load;
A series circuit of a relay-type switching element and a current transformer connected between the two input terminals;
Off, which is connected in parallel to both ends of the open / close portion of the relay type switch element and outputs DC power when the relay type switch element is in a non-conduction state using an AC current flowing from the AC power source through the load. A power supply,
An on-power supply unit that is connected to the secondary side of the current transformer and outputs DC power when the relay switch element is in a conductive state using an alternating current flowing through the secondary side of the current transformer;
An off power supply power detection unit for detecting a physical quantity indicating a direct current power output from the off power supply unit;
An on-power-supply detection unit that detects a physical quantity indicating DC power output from the on-power supply unit;
Based on operation information input from the outside, which is driven by DC power output from the off-power supply unit and the on-power supply unit, the conduction and non-conduction of the relay type switch element are controlled, and the on-power supply power detection When the DC power output from the on-power supply unit is estimated from the physical quantity detected by the unit and the estimated DC power output from the on-power supply unit is less than the predetermined threshold power, the relay And a control unit that controls to switch the type switch element from the conductive state to the non-conductive state.

According to the present invention, when the load current stops due to, for example, the bulb being blown out, and the DC power output from the ON power supply unit suddenly decreases and becomes less than a predetermined threshold power, the relay type switching element Is switched from the conductive state to the non-conductive state, so that the illumination device as the load is automatically turned off. Since the light bulb is exchanged in a state where the lighting device is off, the user does not get an electric shock.

FIG. 1 is a block diagram showing a basic configuration of a two-wire load control apparatus according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a specific configuration of the two-wire load control apparatus. FIG. 3 is a flowchart showing the basic operation of the two-wire load control apparatus. FIG. 4 is a flowchart showing the operation of the first modification of the two-wire load control apparatus. FIG. 5 is a flowchart showing the operation of the second modification of the two-wire load control apparatus. FIG. 6 is a flowchart showing the operation of the third modification of the two-wire load control device. FIG. 7 is a flowchart showing another operation of the third modified example of the two-wire load control device. FIG. 8 is a flowchart showing the operation of the fourth modification of the two-wire load control apparatus. FIG. 9 is a flowchart showing a continuation of the flowchart of FIG.

A two-wire load control apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a basic block configuration of a two-wire load control apparatus 1 according to this embodiment, and FIG. 2 shows a specific circuit configuration. The two-wire load control device 1 includes two

input terminals

11a and 11b connected to an AC power supply 2 and a load 3, respectively, and a relay type switching element 12 and current connected between the two

input terminals

11a and 11b. A series circuit of the transformer 13 is provided. The relay type switch element 12 is a switch element provided with a mechanically driven contact such as a latch type relay. Further, a first bidirectional semiconductor switch element 32 such as a triac is connected in parallel with the relay type switch element 12, and a second bidirectional semiconductor such as a phototriac coupler is connected to the gate of the first bidirectional semiconductor switch element 32. A semiconductor switch element 33 is connected. As the second bidirectional semiconductor switch element 33, an element whose turn-on current value and holding current value are smaller than the turn-on current value and holding current value of the first bidirectional semiconductor switch element 32 is selected. In the following description, the “switch element” refers to any or all of the relay type switch element 12, the first bidirectional semiconductor switch element 32, and the second bidirectional semiconductor switch element 33 provided on the AC side. DC side transistors are excluded.

When both switch elements such as the relay type switch element 12 are in a non-conductive state, the AC current flowing from the AC power source 2 through the load 3 is used for both

terminals

12a and 12b of the open / close portion of the relay type switch element 12. An off power supply unit 14 that outputs DC power is connected. More specifically, both

terminals

12a and 12b of the opening / closing part of the relay type switch element 12 are constituted by diode bridges or the like, and the alternating current flowing from the alternating current power source 2 through the load 3 is converted into a direct current (pulsating current). A first rectifier circuit 15 to be converted is connected in parallel. For example, a resistor that limits current, a Zener diode (constant voltage diode) that clamps a voltage, and a constant voltage circuit (bootstrap circuit) 16 that includes transistors are connected to the first rectifier circuit 15. . The first rectifier circuit 15 and the constant voltage circuit 16 constitute an off power supply unit 14. In the circuit configuration shown in FIG. 2, the off power supply unit 14 has two voltage systems, for example, a high voltage system with a drive voltage of 24V and a low voltage system with a drive voltage of 12V.

The first rectifier circuit 15 is connected to both

terminals

12a and 12b of the opening / closing part of the relay type switch element 12 even when all the switch elements such as the relay type switch element 12 are non-conductive and the load 3 is in the OFF state. Therefore, a weak current flows through the series circuit of the AC power source 2, the load 3, and the first rectifier circuit 15. The current at this time is a minute current that does not cause the load 3 to malfunction, and is set so that the impedance of the off-power supply unit 14 becomes high. When a full-wave rectified pulsating current is input from the first rectifier circuit 15, the voltage waveform of the output from the off power supply unit 14 becomes substantially trapezoidal due to the Zener voltage of the Zener diode. Part of the current output from the off power supply unit 14 is stepped down by the regulator and supplied to the first control unit 21. In parallel with this, the buffer capacitor of the auxiliary power supply unit for CPU operation (first auxiliary power supply unit) 23 is charged. When the voltage of the pulsating current rectified by the first rectifier circuit 15 is lower than the Zener voltage, the buffer capacitor of the auxiliary power supply unit 23 becomes a power source and supplies power to the first control unit 21 via the regulator. To do. Therefore, when the load 3 is in the off state, the buffer capacitor of the auxiliary power supply unit 23 is repeatedly charged and discharged. Similarly, a part of the current output from the off power supply unit 14 is supplied to the second control unit 22, and in parallel therewith, the buffer of the auxiliary power supply unit for opening / closing contacts (second auxiliary power supply unit) 24. Charge the capacitor.

The first rectifier circuit 15 of the off power supply unit 14 is connected to an off power supply power detection unit 30 composed of a diode, resistor, capacitor, transistor, and the like for half-wave rectification. When all switch elements such as the relay type switch element 12 are non-conductive, that is, when the load 3 is in an off state and DC power is output from the off power supply unit 14, the DC current rectified by a half wave by a diode (Pulsating flow) is input to the off power supply power detection unit 30. The transistor is turned on / off in accordance with the voltage (physical quantity) change of the DC current that has been half-wave rectified, a pulse signal is output from the off power supply power detection unit 30, and this pulse signal is input to the first control unit 21. The first control unit 21 can determine that all the switch elements are non-conductive when the pulse signal from the off power supply power detection unit 30 is input. On the other hand, when any one of the switch elements such as the relay type switch element 12 is turned on, the voltage applied to the first rectifier circuit 15 of the off power supply unit 14 is lowered, and the off power supply unit 14 does not operate. Further, the voltage applied to the off power supply power detection unit 30 also decreases, and the pulse signal is not output from the off power supply power detection unit 30. When the pulse signal from the off power supply power detection unit 30 is not input, the first control unit 21 can infer that any one of the switch elements such as the relay type switch element 12 is conductive.

To the secondary side of the current transformer 13, DC power when any switch element such as the relay type switch element 12 is conducted is output using the alternating current flowing through the secondary side of the current transformer 13. An on power supply unit 17 is connected. More specifically, a second rectifier circuit 18 configured by a diode bridge or the like and converting an alternating current flowing from the alternating current power supply 2 via the load 3 into a direct current (pulsating flow) is connected. The second rectifier circuit 18 is connected to a constant voltage circuit 19 composed of a capacitor and a Zener diode. The on power supply unit 17 also has two voltage systems, for example, a high voltage system with a drive voltage of 24V and a low voltage system with a drive voltage of 12V. The output terminal of the high voltage system of the off power supply unit 14 and the output terminal of the high voltage system of the on power supply unit 17 are connected to each other via a backflow prevention diode. Similarly, the output terminal of the low voltage system of the off power supply unit 14 and the output terminal of the low voltage system of the on power supply unit 17 are connected to each other through a backflow preventing diode.

The output terminal of the high voltage system of the on power supply unit 17 is connected to the on power supply power detection unit 31 configured by a resistor and a capacitor, and the voltage between terminals of the capacitor (higher or lower than the threshold voltage). Is input to the first control unit 21. Even when all switch elements such as the relay type switch element 12 are non-conductive, a current flows from the first rectifier circuit 15 of the off power supply unit 14 to the primary side of the current transformer 13. However, the current flowing at this time is a weak current that does not cause the load 3 to malfunction, and the amount of current that flows on the secondary side of the current transformer 13 is further small and almost negligible. Therefore, the voltage between the terminals of the capacitor is lower than the threshold value, and the first control unit 21 can determine that all the switch elements such as the relay type switch element 12 are non-conductive. On the other hand, when any one of the switching elements such as the relay type switching element 12 is turned on, that is, when the load 3 is turned on, a current sufficient to drive the load flows to the primary side of the current transformer 13, and the current is accordingly increased. The amount of current flowing on the secondary side of the transformer 13 also increases. The current flowing on the secondary side of the current transformer 13 is full-wave rectified by the second rectifier circuit 18 and charges the capacitor of the on-power supply unit 17. Then, the voltage at the output terminal of the high voltage system of the on-power supply unit 17 becomes a predetermined voltage, and the inter-terminal voltage (physical quantity) of the capacitor of the on-power supply power detection unit 31 becomes higher than the threshold voltage. Accordingly, the first control unit 21 can determine that any one of the switch elements such as the relay type switch element 12 is conductive.

For example, when the user operates an input unit 25 such as an operation handle or a wireless remote control device provided on a wall surface, the control unit 20 conducts and does not conduct a switch element such as the relay switch element 12 according to the operation information. To control. The control unit 20 includes, for example, a CPU and includes a first control unit 21 that is driven at a low voltage (for example, 3V) and a second control unit 22 that is driven at a high voltage (for example, 24V). The first control unit 21 is connected to output terminals of the low voltage system of the off power supply unit 14 and the on power supply unit 17 through a regulator. The regulator is for stepping down the drive voltage 12V of the low voltage system to a lower voltage, for example, about 3V. The second control unit 22 outputs a large electric power for driving the electromagnet device of the relay type switching element 12. In addition, the control unit 20 includes an automatic switch-off display device composed of an LED element, a speaker, and the like, and the relay switch element 12 is automatically switched from a conductive state to a non-conductive state as will be described later. The user can be notified of this.

Furthermore, an auxiliary power supply unit 23 for operating the CPU is connected between the output terminals of the low voltage system of the off power supply unit 14 and the on power supply unit 17 and the first control unit 21 via a regulator. In addition, an auxiliary power supply unit 24 for opening and closing the contacts of the relay type switch element 12 is connected between the output terminals of the high voltage system of the off power supply unit 14 and the on power supply unit 17 and the second control unit 22. Each of the auxiliary power supply unit 23 for operating the CPU and the auxiliary power supply unit 24 for opening and closing the contacts is composed of a buffer capacitor or the like. The buffer capacitor of the auxiliary power supply unit 24 for opening and closing the contacts switches the relay switch element 12 from the non-conducting state to the conducting state, and further switches from the conducting state to the non-conducting state continuously, that is, a predetermined amount that is driven at least twice. It has a capacity capable of charging the power.

When the load 3 is off, that is, when the relay type switch element 12, the first bidirectional semiconductor switch element 32, and the second bidirectional semiconductor switch element 33 are all non-conductive, the load 3 is turned on from the input unit 25. When the operation information is input, the first control unit 21 inputs a drive signal to the transistor connected to the primary light emitting element of the second bidirectional semiconductor switch element 33. As a result, the second bidirectional semiconductor switch element 33 becomes conductive, and a load current starts to flow through the load 3. When the load 3 is a lighting device using, for example, a low-brightness LED bulb, and the load current is small and less than the turn-on current of the first bidirectional semiconductor switch element 32, the first bidirectional semiconductor switch element 32 is used. Is not conducted, and a load current is caused to flow by the second bidirectional semiconductor switch element 33. On the other hand, when the load 3 is a lighting device using, for example, a fluorescent lamp or an incandescent lamp, and the load current is greater than or equal to the turn-on current of the first bidirectional semiconductor switch element 32, the first bidirectional semiconductor switch element 32 is The second bidirectional semiconductor switch element 33 becomes non-conductive. Further, after the first bidirectional semiconductor switch element 32 is turned on, the first control unit 21 outputs a drive signal for turning on the relay type switch element 12 to the second control unit 22, and the relay type switch element 12 becomes conductive, and the first bidirectional semiconductor switch element 32 becomes non-conductive. That is, the control unit 20 always switches the relay switch element 12 from the non-conductive state to the conductive state after switching the first bidirectional semiconductor switch element 32 from the non-conductive state to the conductive state.

Next, the basic operation of the two-wire load control device 1 according to this embodiment will be described. FIG. 3 is a flowchart showing the operation when an illumination device using an incandescent bulb is connected as the load 3. First, it is assumed that the incandescent bulb is normal and does not run out of bulb. The description of the conduction sequence of the relay type switch element 12, the first bidirectional semiconductor switch element 32, and the second bidirectional semiconductor switch element 33 is omitted.

When the operation information for turning on the load 3 is input from the input unit 25 (# 2) when the relay type switch element 12 is non-conductive (# 1), the first control unit 21 turns the relay type switch element 12 on. In order to switch from the non-conductive state to the conductive state, a drive signal is output (# 3). The second control unit 22 receives this drive signal and outputs drive power for driving the electromagnet device of the relay type switching element 12 (# 4). This driving power is supplied, for example, by discharging the buffer capacitor of the auxiliary power supply unit 24. Thereby, the switching contact of the relay type switch element 12 is switched from the non-conductive state to the conductive state (# 5). When the relay type switch element 12 becomes conductive, the load current flows in the order of the AC power source 2, the load 3, the relay type switch element 12, the current transformer 13, and the AC power source 2. At this time, the current flowing to the secondary side of the current transformer 13 is relatively large and is rectified by the second rectifier circuit 18 of the on-power supply unit 17, and the output terminal of the high-voltage system and the output of the constant-voltage system of the on-power supply unit 17. Two systems of DC power with different voltages are output from the terminals. The on-power-supply power detection unit 31 is connected to the output terminal of the high-voltage system of the on-power supply unit 17. In the first control unit 21, the output voltage of the on-power supply power detection unit 31 is at a high level. In addition, since no current flows through the first rectifier circuit 15 of the off power supply unit 14 connected in parallel to the open / close contact of the relay type switch element 12, the half-wave rectified pulsating current is not supplied to the off power supply power detection unit 30. No pulse signal is output from the off power supply power detector 30. Accordingly, the first control unit 21 determines that the open / close contact of the relay type switch element 12 is conductive and the load 3 is in an ON state.

In the case of a lighting device using an incandescent bulb, a relatively large current flows as a load current. Therefore, the DC power sufficient to drive the relay type switch element 12 is output from the ON power supply unit 17. However, in the case of an illuminating device that uses only one incandescent bulb, if the filament of the incandescent bulb breaks and the bulb breaks, the load current does not flow suddenly, and DC power is not output from the on power supply unit 17. Or in the case of the illuminating device which uses a some incandescent lamp, the load electric current value falls by the bulb | ball breakage of one of incandescent lamps, and the direct-current electric power output from the ON power supply part 17 falls. Further, since the relay type switch element 12 remains conductive, no DC power is output from the off power supply unit 14. At this stage, the buffer capacitor of the contact opening / closing auxiliary power supply unit 24 is still charged with sufficient power to drive the relay switch element 12. Similarly, the buffer capacitor of the CPU operation auxiliary power supply unit 23 is charged with sufficient power to drive the control unit 20. However, as time passes, the electric power charged in the contact opening / closing auxiliary power supply unit 24 and the CPU operation auxiliary power supply unit 23 is gradually discharged.

When DC power is no longer output from the on power supply unit 17 or when the amount of DC power output from the on power supply unit 17 decreases, the output voltage from the on power supply power detection unit 31 becomes lower than the threshold voltage. The first control unit 21 monitors the output voltage from the on-power supply power detection unit 31. When the output voltage from the on-power supply power detection unit 31 becomes lower than the threshold voltage (NO in # 6), the load 3. It is determined that a trouble such as running out of the ball has occurred in No. 3 (# 7). If the first control unit 21 determines that a trouble such as a broken ball has occurred in the load 3, the first control unit 21 outputs a drive signal in order to switch the relay-type switch element 12 from the conductive state to the non-conductive state (# 8). The second control unit 22 receives this drive signal and outputs drive power for driving the electromagnet device of the relay type switch element 12 (# 9). Thereby, the switching contact of the relay type switch element 12 is switched from the conductive state to the non-conductive state (# 10). Since the first bidirectional semiconductor switch element 32 and the second bidirectional semiconductor switch element 33 are self-extinguishing semiconductor switch elements, the relay type switch element 12 and the first bidirectional semiconductor switch element 32 are in conduction. The self-extinguishing is done at the time. Therefore, unless the drive signal is input from the first control unit 21 to the transistor connected to the primary side light emitting element of the second bidirectional semiconductor switch element (phototriac coupler) 33, re-ignition is not performed.

Next, the operation of the first modification of the two-wire load control device 1 according to this embodiment will be described. FIG. 4 is a flowchart showing an operation when the load 3 is frequently turned on and off, for example. Electric power for switching between conduction and non-conduction of the relay type switch element 12 is supplied from the contact opening / closing auxiliary power supply unit 24. As described above, the contact opening / closing auxiliary power supply unit 24 has a capacity capable of charging predetermined power sufficient to continuously drive the relay type switching element 12 at least twice. However, if the user repeatedly turns on and off the load 3 in a row, the contact opening / closing auxiliary power supply unit 24 may not have enough power to drive the relay switch element 12. Alternatively, there may be a case where the DC power is not output from the off power supply unit 14 and the on power supply unit 17 and the contact opening / closing auxiliary power supply unit 24 is not charged due to a power failure or a break of the load 3 from the beginning.

When the relay type switch element 12 is in a non-conductive state (# 11), when the operation information for turning on the load 3 is input from the input unit 25 (# 12), the first control unit 21 is connected to the contact opening / closing auxiliary power supply unit. It is determined whether or not the electric power sufficient to drive the relay type switch element 12 is charged to 24 (# 13). Here, the charge state of the contact opening / closing auxiliary power supply unit 24 is obtained by, for example, counting the number of pulse signals output from the off power supply power detection unit 30 between the previous driving of the relay type switch element 12 and the present time. If this is the case, the charging time is obtained, and thereby the power charged in the buffer capacitor of the contact switching auxiliary power supply unit 24 can be estimated. If it is determined that the contact opening / closing auxiliary power supply unit 24 is not charged with enough power to drive the relay-type switch element 12 (NO in # 13), the first control unit 21 opens the contact opening / closing auxiliary power supply unit. It is determined whether or not the battery can be charged (# 14). For example, when the load 3 is out of sphere and no DC power is output from the off power supply unit 14 and the on power supply unit 17, the contact opening / closing auxiliary power supply unit 24 cannot be charged. Accordingly, when the contact opening / closing auxiliary power supply unit 24 cannot be charged (NO in # 14), the first control unit 21 maintains the relay switch element 12 in the non-conductive state regardless of the operation information. Actually, the electric power charged in the buffer capacitor of the auxiliary power supply unit 23 for CPU operation is eventually discharged, and the first control unit 21 does not function. On the other hand, when the contact opening / closing auxiliary power supply unit 24 can be charged (YES in # 14), the control unit 21 has enough power to drive the relay switch element 12 in the contact opening / closing auxiliary power supply unit 24. After being charged, a drive signal is output (# 15). In Step # 13, when it is determined that the contact switching auxiliary power supply 24 is charged with enough power to drive the relay switch element 12, the first controller 21 determines that the relay switch element 12 In order to switch the non-conducting state to the conducting state, a drive signal is immediately output (# 15). The operations from step # 16 to # 22 are the same as steps # 4 to # 10 in the flowchart of FIG.

Next, the operation of the second modification of the two-wire load control device 1 according to this embodiment will be described. FIG. 5 is a flowchart showing an operation when a lighting device using a plurality of light bulbs, for example, is connected as the load 3. In FIG. 5, steps # 1 to # 10 are the same as steps # 1 to # 10 in the flowchart shown in FIG.

In this case, even if one bulb breaks down, the other bulb is still alive. On the other hand, if the relay type switch element 12 becomes non-conductive in step # 10, all the light bulbs are turned off, and it becomes impossible to know which light bulb has caused the bulb to break. Generally, when all the light bulbs are extinguished, the user tends to try to operate the input unit 25 such as an operation handle or a wireless remote controller provided on the wall surface for the time being. Therefore, when operation information for turning on the load 3 is newly input from the input unit 25 (# 30), the first control unit 21 can only drive the relay switch element 12 to the contact opening / closing auxiliary power supply unit 24. It is determined whether or not the electric power is charged (# 31). When it is determined that the contact opening / closing auxiliary power source 24 is charged with power sufficient to drive the relay switch element 12 (YES in # 31), the first controller 21 turns the relay switch element 12 on. In order to switch from the non-conductive state to the conductive state, a drive signal is output (# 32), whereby the relay switch element 12 is made conductive (# 33, # 34). When the relay type switch element 12 is turned on, the live bulb is turned on, so that the user can know which bulb has run out. Then, the first control unit 21 outputs a drive signal again to switch the relay type switch element 12 from the conductive state to the nonconductive state (# 35), thereby making the relay type switch element 12 nonconductive (#). 36, # 37), the light is turned off again. When the operation information for turning on the load 3 is input from the input unit 25 (# 38), the first control unit 21 cancels the non-conduction state of the relay type switch element 12 and switches to the conduction state (# 39), the load 3 is turned on. When the user inputs operation information for turning on the load 3 from the input unit 25 without replacing the bulb that has broken the bulb, the relay switch element 12 may be switched from the conductive state to the non-conductive state again. In this case, the operation is based on the operation of a fourth modification described later.

Note that the input unit 25 is not limited to an operation handle or a wireless remote controller provided on a wall surface, and may be a human body sensor installed in a toilet, an entrance, a hallway, or the like. Further, the human body sensor may be connected to the first control unit 21 by wire or may be connected wirelessly. In the latter case, it is preferable that the receiver of the wireless remote controller included in the first control unit 21 is also used. Further, between steps # 1 and # 2 in FIG. 5, it is determined whether or not the contact opening / closing auxiliary power supply unit 24 shown in FIG. 4 is charged with power sufficient to drive the relay switch element 12. Step # 14 for determining whether or not # 13 and the contact opening / closing auxiliary power supply 24 can be charged may be provided. Furthermore, step # 14 may be provided between steps # 31 and # 32 to determine whether or not the contact opening / closing auxiliary power supply unit 24 can be charged.

Next, the operation of the third modification of the two-wire load control device 1 according to this embodiment will be described. 6 and 7 show that when the relay switch element 12 is switched from the conductive state to the nonconductive state due to a shortage of DC power output from the on-power supply unit 17, the relay switch element 12 is automatically set to the user. It is a flowchart which shows operation | movement in the case of notifying that it switched from the conduction | electrical_connection state to the non-conduction state. 6 and 7, steps # 1 to # 10 are the same as steps # 1 to # 10 in the flowchart shown in FIG.

If a bulb break occurs when the user is absent and the relay-type switch element 12 is automatically switched from a conductive state to a non-conductive state, the user thinks that someone else has turned off the load 3. The load 3 is turned on again by operating the operation handle or the wireless remote controller. However, there is a high possibility that the DC power is not output from the auxiliary power supply unit 17 due to the broken ball, and the contact opening / closing auxiliary power supply unit 24 cannot be charged. Therefore, an automatic switch-off display device 26 composed of an element that visually displays information, such as an LED element, or an element that auditorily displays information, such as a chime, is provided in the control unit 20. When the type switch element 12 becomes non-conductive, these LED elements may be turned on or blinked, or a chime or the like may be driven (# 40). As a result, the user can know that the switch has been automatically turned off due to a ball break. Since these LED elements and chimes are driven by the power charged in the auxiliary power source 23 for CPU operation, they cannot be driven for a long time. Therefore, when the user operates the operation handle or the wireless remote control device and the operation information for turning on the load 3 is input (# 41), the driving of these LED elements and chimes is stopped to automatically The switch-off display may be canceled (# 42). Alternatively, as shown in FIG. 7, when the user operates the operation handle or the wireless remote control device to input operation information for turning on the load 3 (# 43), these LED elements and chimes are driven. Then, an automatic switch-off may be displayed (# 44).

Next, the operation of the fourth modification of the two-wire load control device 1 according to this embodiment will be described. FIG. 8 and FIG. 9 are flowcharts showing the operation when a load having a load current value close to the holding current value of the first bidirectional semiconductor switch element 32 such as a high-intensity LED bulb or a bulb-type fluorescent lamp is used. When the load 3 having a small load current value is connected, the direct-current power output from the on power supply unit 17 is less than a predetermined threshold power even if the load 3 itself is not blown out. There is a possibility that the relay-type switch element 12 is switched to non-conduction. When the relay-type switch element 12 is switched to non-conduction, the light bulb is extinguished, so that the user may misunderstand that the ball has run out. Alternatively, when the load 3 is an illuminating device that uses a plurality of light bulbs, all the light bulbs are extinguished even if some of the light bulbs are broken.

When the operation information for turning on the load 3 is input from the input unit 25 (# 52) while all the

switch elements

12, 32 and 33 are non-conductive (# 51), the first control unit 21 The bidirectional semiconductor switch element 33 is turned on (# 53), whereby a load current starts to flow through the load 3. Here, if the load current value is less than the turn-on current value of the first bidirectional semiconductor switch element 32, the first bidirectional semiconductor switch element 32 is not conducted (NO in # 54), and the load 3 is A current is passed only by the two-way semiconductor switch element 33. On the other hand, if the load current value is equal to or greater than the turn-on current value of the first bidirectional semiconductor switch element 32, the first bidirectional semiconductor switch element 32 becomes conductive (YES in # 54). Then, the first control unit 21 determines whether or not the output voltage from the on-power supply detection unit 31 is lower than the threshold voltage, that is, the DC power output from the on-power supply unit 17 is less than the predetermined threshold power. (# 55). When it is determined that the DC power output from the ON power supply unit 17 is less than the predetermined threshold power (NO in # 55), the load current value is not so large and the first bidirectional semiconductor switch element 32 loads the load. Since the current can flow, the first control unit 21 does not conduct the relay switch element 12 and maintains the non-conduction state. On the other hand, when it is determined that the DC power output from the ON power supply unit 17 is equal to or higher than the predetermined threshold power (YES in # 55), the load current value is large and the load current is caused to flow by the relay type switch element 12. Is considered preferable. Accordingly, the first control unit 21 determines whether or not the relay-type switch element 12 is set to be non-conductive (# 56). When the load 3 is first connected to the two-wire load control device 1, since the non-conducting setting is not made in the relay type switch element 12 (YES in # 56), the first control unit 21 is connected to the relay type switch element 12. The switch element 12 is turned on (# 57). After the relay switch element 12 is turned on, the first control unit 21 monitors the output voltage from the on-power supply power detection unit 31, and based on the value of the DC power output from the on-power supply unit 17, It is monitored whether or not a trouble such as a broken ball has occurred in the load 3 (# 58).

In step # 55, when the load current is not so large and the DC power output from the ON power supply unit 17 slightly exceeds the predetermined threshold power, the other loads connected to the same AC power supply 2 are turned on, etc. If a voltage drop occurs, the DC power output from the on-power supply unit 17 may be lower than a predetermined threshold power (NO in # 58). In the fourth modification, the first control unit 21 switches the relay type switch element 12 from the conductive state to the nonconductive state (# 59), and switches the relay type switch element 12 to the nonconductive state due to power shortage. The number of times is counted (# 60). That is, when the load current is not so large, the relay switch element 12 is frequently switched to the non-conductive state by turning on another load connected to the same AC power supply 2, thereby turning on the load 3. And is expected to be repeated off. If the switching contacts of the relay type switch element 12 are frequently opened and closed or the load 3 is frequently turned on / off, the relay type switch element 12 and the load 3 will be deteriorated.

Therefore, when the number K of switching the relay type switching element 12 to the non-conducting state due to power shortage within a certain period reaches the predetermined number n (YES in # 61), the relay type switching element 12 is not conducted thereafter. As described above, the non-conduction setting is performed for the relay type switch element 12 (# 62). The first control unit 21 performs non-conduction setting for the relay type switch element 12, and then returns to step # 53 to conduct the second bidirectional semiconductor switch element 33 and turn on the load 3. Note that each of the first bidirectional semiconductor switch element 32 and the second bidirectional semiconductor switch element 33 is a self-extinguishing semiconductor switch element, and automatically becomes non-conductive at the zero-cross point of the AC voltage. Accordingly, the first control unit 21 turns on the load 3 and makes the relay switch element 12 non-conductive, the 1st of the second bidirectional semiconductor switch element 33 every 1/2 cycle of the AC power supply 2. A gate drive signal is input to the next side.

As described above, according to the configuration of the present embodiment, when the load current is stopped due to, for example, the bulb being blown, and the DC power output from the on power supply unit 17 is less than the predetermined threshold power. In addition, since the relay switch element 12 is quickly switched from the conductive state to the non-conductive state, the bulb can be replaced while the load 3 is off, and the user is not shocked. Further, it is necessary to drive the electromagnet device in order to switch the open / close contact of the relay type switch element 12 from the conductive state to the non-conductive state. Since the electromagnet device is driven at the remaining stage, the switching contact of the relay type switch element 12 can be surely made non-conductive.

It should be noted that the present invention is not limited to the description of the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the first bidirectional semiconductor switch element 32 does not necessarily need to be a triac, and may be an IGBT or FET that is connected in antiparallel. The second bidirectional semiconductor switch element 33 is not necessarily required. Instead of the photo triac, a thyristor or a diac (trigger diode) may be connected to the triac gate to input a gate signal. Good.

In addition, the two-wire load control device according to the present invention does not need to have all of the configuration of the above embodiment, at least,
Two input terminals respectively connected to an AC power source and a load;
A series circuit of a relay-type switching element and a current transformer connected between the two input terminals;
Off, which is connected in parallel to both ends of the open / close portion of the relay type switch element and outputs DC power when the relay type switch element is in a non-conduction state using an AC current flowing from the AC power source through the load. A power supply,
An on-power supply unit that is connected to the secondary side of the current transformer and outputs DC power when the relay switch element is in a conductive state using an alternating current flowing through the secondary side of the current transformer;
An off power supply power detection unit for detecting a physical quantity indicating a direct current power output from the off power supply unit;
An on-power-supply detection unit that detects a physical quantity indicating DC power output from the on-power supply unit;
Based on operation information input from the outside, which is driven by DC power output from the off-power supply unit and the on-power supply unit, the conduction and non-conduction of the relay type switch element are controlled, and the on-power supply power detection When the DC power output from the on-power supply unit is estimated from the physical quantity detected by the unit and the estimated DC power output from the on-power supply unit is less than the predetermined threshold power, the relay It is only necessary to include a control unit that controls the type switch element to switch from the conductive state to the non-conductive state.

In addition, the power supply device further includes an auxiliary power supply unit for driving the relay type switch element, and the auxiliary power supply unit switches the relay type switch element from a non-conductive state to a conductive state, and continuously from the conductive state to the nonconductive state. It is preferable to be able to charge a predetermined amount of electric power for switching to.

Further, it is preferable that the control unit estimates a charging state of the auxiliary power supply unit from a physical quantity detected by the off power supply power detection unit when the relay type switching element is in a non-conductive state.

In addition, the control unit determines that the relay switch element is in a non-conductive state, operation information for turning on the load is input from the outside, and the predetermined power is charged in the auxiliary power unit. In this case, it is preferable to immediately switch the relay type switch element from the non-conductive state to the conductive state in accordance with the operation information.

Further, the control unit determines that the relay switch element is in a non-conductive state, operation information for turning on the load is input from the outside, and the predetermined power is not charged in the auxiliary power unit. When the operation information is temporarily suspended, when it is determined that the auxiliary power supply unit has been charged with enough power to drive the relay switch element, the relay type is determined according to the operation information. It is preferable to switch the switch element from the non-conductive state to the conductive state.

Alternatively, when the control unit determines that the relay switch element is in a non-conductive state, operation information for turning on the load is input from the outside, and the auxiliary power unit cannot be charged with the predetermined power Regardless of the operation information, it is preferable to maintain the relay type switching element in a non-conductive state.

Further, an operation member that is operated by a user and for inputting the operation information is further provided,
The control unit determines that the DC power output from the ON power supply unit is less than the predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then performing the operation. When the operation information for turning on the load is input by the member and it is determined that the predetermined power is charged in the auxiliary power supply unit, the relay-type switch element is turned off according to the operation information. It is preferable that the state is switched from the state to the conductive state, and the relay-type switch element is continuously switched from the conductive state to the non-conductive state, whereby the load can be temporarily turned on.

Alternatively, it further comprises a receiving unit for receiving a human body sensing signal transmitted by radio from a human body sensor provided in a place away from the two-wire load control device,
The control unit determines that the DC power output from the ON power supply unit is less than the predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then the human body When the human body sensing signal from the sensing sensor is received and it is determined that the predetermined power is charged in the auxiliary power supply unit, the relay switch element is turned off according to the human body sensing signal. It is preferable that the relay-type switching element is continuously switched from the conductive state to the non-conductive state so that the load can be temporarily turned on.

Further, it further comprises automatic switch-off display means for visually or audibly displaying that the relay-type switch element has been switched from the conductive state to the non-conductive state,
The control unit determines that the DC power output from the ON power supply unit is less than a predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then automatically Preferably, the switch-off display means is driven to notify that the relay type switch element is automatically switched from the conductive state to the non-conductive state.

Or further comprising automatic switch-off display means for visually or audibly indicating that the relay-type switch element has been switched from the conductive state to the non-conductive state,
The control unit determines that the DC power output from the ON power supply unit is less than a predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then externally When new operation information for turning on the load is inputted, the automatic switch-off display means is driven, and the relay switch element is automatically switched from the conductive state to the non-conductive state by the user. It is preferable to notify this.

In addition, the control unit determines that the DC power output from the ON power supply unit is less than a predetermined threshold power, thereby switching the relay switch element from the conductive state to the non-conductive state, and then automatically In addition, the relay type switching element is switched from the non-conducting state to the conducting state, and the number of times the relay type switching element is switched from the conducting state to the non-conducting state is counted. It is preferable to stop the function of switching the relay switch element from the non-conductive state to the conductive state and maintain the relay switch element in the non-conductive state.

Further, it is preferable that the control unit cancels the maintenance of the non-conducting state of the relay switch element when the operation member is operated in a specific manner.

Alternatively, the receiving unit receives a signal transmitted from a wireless remote control device operated by a user,
It is preferable that the control unit cancels the maintenance of the non-conducting state of the relay switch element when the receiving unit receives a specific operation signal transmitted from the wireless remote control signal.

Further, it is preferable that the control unit stops driving the automatic switch-off display means when the operation member is operated in a specific manner.

Alternatively, the receiving unit receives a signal transmitted from a wireless remote control device operated by a user,
The control unit preferably stops driving the automatic switch-off display means when the receiving unit receives a specific operation signal transmitted from the wireless remote control signal.

Further, the control unit determines that the DC power output from the ON power supply unit is less than a predetermined threshold power, and drives the relay switch element to the auxiliary power supply unit also by the OFF power supply unit. When it is determined that as much power as possible cannot be charged, it is preferable to maintain the relay type switching element in a non-conductive state.

Further, it is preferable to further include at least one bidirectional semiconductor switching element connected in parallel with the relay type switching element.

Further, it is preferable that the control unit switches the relay type switch element from the non-conduction state to the conduction state after switching the bidirectional semiconductor switch element from the non-conduction state to the conduction state first.

In addition, the control unit estimates a load current value when the load is on from the physical quantity detected by the on-power supply power detection unit, and the estimated load current value is less than a predetermined current threshold value It is preferable to conduct only the bidirectional semiconductor switch element.

This application is based on Japanese Patent Application No. 2012-047819, and the contents thereof should be incorporated into the present invention as a result by referring to the specification and drawings of the above patent application. Further, although the present invention has been fully described by the embodiments with reference to the accompanying drawings, it is apparent to those skilled in the art that various changes and modifications are possible. . Therefore, such changes and modifications do not depart from the scope of the present invention and should be construed as being included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 2 wire type load control apparatus 2 AC power supply 3

Load

11a, 11b Input terminal 12 Relay type switch element 13 Current transformer 14 Off power supply part 15 1st rectifier circuit 16 Constant voltage circuit 17 On power supply part 18 2nd rectifier circuit 19 Constant Voltage circuit 20 Control unit 21 First control unit 22 Second control unit 23 Auxiliary power supply unit for CPU operation (first auxiliary power supply unit)
24 Auxiliary power supply for opening and closing contacts (second auxiliary power supply)
30 off power supply power detection unit 31 on power supply power detection unit 32 first bidirectional semiconductor switch element (triac)
33 Second Bidirectional Semiconductor Switch Element (Phototriac Coupler)

Claims

Two input terminals respectively connected to an AC power source and a load;
A series circuit of a relay-type switching element and a current transformer connected between the two input terminals;
Off, which is connected in parallel to both ends of the open / close portion of the relay type switch element and outputs DC power when the relay type switch element is in a non-conduction state using an AC current flowing from the AC power source through the load. A power supply,
An on-power supply unit that is connected to the secondary side of the current transformer and outputs DC power when the relay switch element is in a conductive state using an alternating current flowing through the secondary side of the current transformer;
An off power supply power detection unit for detecting a physical quantity indicating a direct current power output from the off power supply unit;
An on-power-supply detection unit that detects a physical quantity indicating DC power output from the on-power supply unit;
Based on operation information input from the outside, which is driven by DC power output from the off-power supply unit and the on-power supply unit, the conduction and non-conduction of the relay type switch element are controlled, and the on-power supply power detection When the DC power output from the on-power supply unit is estimated from the physical quantity detected by the unit and the estimated DC power output from the on-power supply unit is less than the predetermined threshold power, the relay A two-wire load control device comprising: a control unit configured to control the type switch element to switch from a conductive state to a non-conductive state.
An auxiliary power supply unit for driving the relay-type switch element is further provided, and the auxiliary power supply unit switches the relay-type switch element from a non-conductive state to a conductive state, and continuously switches from a conductive state to a non-conductive state. The two-wire load control device according to claim 1, wherein only predetermined power can be charged.
The said control part estimates the charge state of the said auxiliary power supply part from the physical quantity detected by the said off power supply electric power detection part, when the said relay type switch element is a non-conduction state. 2-wire load control device.
When the control unit determines that the relay switch element is in a non-conductive state, operation information for turning on the load is input from the outside, and the predetermined power is charged in the auxiliary power source unit The two-wire load control device according to claim 3, wherein the relay type switching element is immediately switched from a non-conducting state to a conducting state in accordance with the operation information.
When the control unit determines that the relay switch element is in a non-conductive state, operation information for turning on the load is input from the outside, and the predetermined power is not charged in the auxiliary power source unit Temporarily holds the operation information, and when it is determined that the auxiliary power supply unit has been charged with power sufficient to drive the relay switch element, according to the operation information, the relay switch element The two-wire load control device according to claim 3 or 4, wherein the switch is switched from a non-conductive state to a conductive state.
When the control unit determines that the relay switch element is in a non-conductive state, operation information for turning on the load is input from the outside, and the auxiliary power unit cannot be charged with the predetermined power, 5. The two-wire load control device according to claim 3, wherein the relay-type switch element is maintained in a non-conductive state regardless of the operation information.
An operation member that is operated by a user and for inputting the operation information is further provided.
The control unit determines that the DC power output from the ON power supply unit is less than the predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then performing the operation. When the operation information for turning on the load is input by the member and it is determined that the predetermined power is charged in the auxiliary power supply unit, the relay-type switch element is turned off according to the operation information. 4. The switch according to claim 3, wherein the load can be temporarily turned on by switching the relay-type switch element from the conductive state to the non-conductive state continuously. Linear load control device.
A receiving unit for receiving a human body sensing signal transmitted by radio from a human body sensor provided at a location apart from the two-wire load control device;
The control unit determines that the DC power output from the ON power supply unit is less than the predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then the human body When the human body sensing signal from the sensing sensor is received and it is determined that the predetermined power is charged in the auxiliary power supply unit, the relay switch element is turned off according to the human body sensing signal. 4. The two-wire according to claim 3, wherein the relay-type switching element is continuously switched from a conduction state to a non-conduction state, whereby the load can be temporarily turned on. Type load control device.
Further comprising automatic switch-off display means for visually or audibly indicating that the relay-type switch element has been switched from a conductive state to a non-conductive state;
The control unit determines that the DC power output from the ON power supply unit is less than a predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then automatically 9. The switch-off display means is driven to notify that the relay type switch element is automatically switched from a conductive state to a non-conductive state. The two-wire load control device described.
Further comprising automatic switch-off display means for visually or audibly indicating that the relay-type switch element has been switched from a conductive state to a non-conductive state;
The control unit determines that the DC power output from the ON power supply unit is less than a predetermined threshold power, thereby switching the relay switch element from a conductive state to a non-conductive state, and then externally When new operation information for turning on the load is inputted, the automatic switch-off display means is driven, and the relay switch element is automatically switched from the conductive state to the non-conductive state by the user. The two-wire load control device according to any one of claims 1 to 8, wherein notification is made.
The control unit determines that the DC power output from the ON power supply unit is less than a predetermined threshold power, and automatically switches the relay switch element from the conductive state to the non-conductive state, and then automatically The relay switch element is switched from a non-conductive state to a conductive state, and the number of times the relay switch element is switched from a conductive state to a non-conductive state is counted, and when the count value reaches a predetermined number, A function dependent on claim 2, claim 3, or claim 3, wherein the function of switching the relay type switch element from the non-conducting state to the conducting state is stopped and the relay type switching element is maintained in the nonconductive state. The two-wire load control device according to claim 10 that is dependent on item 9 or claim 3.
The two-wire load control device according to claim 7, wherein the controller releases the maintenance of the non-conducting state of the relay switch element when the operation member is operated in a specific manner.
The receiving unit receives a signal transmitted from a wireless remote control device operated by a user,
9. The control unit according to claim 8, wherein when the receiving unit receives a specific operation signal transmitted from the wireless remote control signal, the control unit releases the maintenance of the non-conducting state of the relay switch element. The two-wire load control device described.
The two-wire system according to claim 9, which is dependent on claim 7, wherein the control unit stops driving the automatic switch-off display means when the operation member performs a specific operation. Load control device.
The receiving unit receives a signal transmitted from a wireless remote control device operated by a user,
9. The control unit according to claim 8, wherein the control unit stops driving the automatic switch-off display means when the receiving unit receives a specific operation signal transmitted from the wireless remote control signal. The two-wire load control device according to claim 10.
The control unit can determine that the DC power output from the ON power supply unit is less than a predetermined threshold power, and can only drive the relay switch element to the auxiliary power supply unit by the OFF power supply unit. The two-wire load control device according to any one of claims 3 to 15, wherein the relay-type switch element is maintained in a non-conducting state when it is determined that the power of the power cannot be charged. .
The two-wire load control device according to any one of claims 1 to 16, further comprising at least one bidirectional semiconductor switch element connected in parallel with the relay type switch element.
The said control part switches the said relay type switch element from a non-conduction state to a conduction | electrical_connection state after switching the said bidirectional | two-way semiconductor switch element from a non-conduction state first to a conduction | electrical_connection state of Claim 17 characterized by the above-mentioned. Two-wire load control device.
The control unit estimates a load current value when the load is on from the physical quantity detected by the on-power supply power detection unit, and when the estimated load current value is less than a predetermined current threshold, The two-wire load control device according to claim 17 or 18, wherein only the bidirectional semiconductor switch element is made conductive.