WO2010035082A2

WO2010035082A2 - Hybrid relay and control terminal apparatus

Info

Publication number: WO2010035082A2
Application number: PCT/IB2009/006248
Authority: WO
Inventors: Yasuhiro Sumino; Tomoaki Sasaki; Kouji Yamato; Kiwamu Shibata; Kiyoshi Goto; Hiroyuki Kudo; Susumu Nakano; Hajime Yabu; Kel Miura
Original assignee: Panasonic Electric Works Co., Ltd.
Priority date: 2008-09-25
Filing date: 2009-09-23
Publication date: 2010-04-01
Also published as: WO2010035082A3

Abstract

A hybrid relay includes a first mechanical contact switch opened and closed by a first driving unit, a second mechanical contact switch opened and closed by a second driving unit operating independent of the first driving unit, and a semiconductor switch serially connected to the second mechanical contact switch. In the hybrid relay, the first mechanical contact switch is connected in parallel to the second mechanical contact switch and the semiconductor switch which are connected serially, on a power feed path to a load from a power source; the first mechanical contact switch is a latch type mechanical contact switch; and each of second mechanical contact switch and the semiconductor switch becomes conductive before opening and closing of the contact portion of the first mechanical contact switch and becomes non-conductive after opening and closing of the contact portion of the first mechanical contact switch.

Description

HYBRID RELAY AND CONTROL TERMINAL APPARATUS

Field of the Invention

The present invention relates to a hybrid relay having a mechanical contact switch as well as a semiconductor switch and a control terminal apparatus having same.

Background of the Invention

Conventionally, a hybrid relay having a mechanical contact switch and a semiconductor switch connected in parallel therewith has been used in order to switch between the supply and the cutoff of a power to a load, e.g., a lighting fixture equipped with an inverter circuit. Such a load having the inverter circuit is provided with a large capacity smoothing capacitor which serves to convert an AC voltage to a DC voltage.

In such a load, since a large current flows into this smoothing capacitor when the power is inputted to the load from an AC power source, there is generated an inrush or surge current to the load. Especially, under the condition of a high power supply voltage and heavy load, the inrush current flowing into the load becomes large, such that the large current originating from the inrush current flows in the hybrid relay connected between the load and the AC power source as well.

Therefore, in the hybrid relay connected to such a

-1-

CONFIRMATION COPV load, only the semiconductor switch is firstly turned on

(closed) to make the inrush current flow therethrough, and then when the current supplied to the load becomes stable, the mechanical contact switch is turned on (closed) (see, e.g., Patent Document 1) . By operating in this manner, it is possible to suppress the large current flowing through the mechanical contact switch in the hybrid relay, thereby avoiding a contact fusion caused by an arc generation which can take place immediately before a pair of contacts make contact if otherwise.

As described above, the hybrid relay is of a structure having a semiconductor switch in order to prevent the contact fusion in the mechanical contact switch, and the power supply to the load is started by turning off the mechanical contact switch while turning on the semiconductor switch. Moreover, a hybrid relay is suggested includes an additional mechanical contact switch (referred to as 'second switch' hereinafter) for turning on the semiconductor switch before turning on the mechanical contact switch (referred to as ^λfirst switch' hereinafter) (see, e.g., Patent Document 2) .

Patent Document 1: Japanese Patent Laid-open Application No. Hll-238441

Patent Document 2: Japanese Patent Laid-open Application No. H05-054772 In the hybrid relay of Patent Document 2, the first and the second switch are normal excitation type switch, which are "off" unless they are energized, and a single magnetic coil is commonly used for both of them. Also, by making the distance between the contacts of the first switch differ from that of the second switch, the opening/closing timings of the first and the second switch are set such that the second switch is turned on prior to the first switch. Therefore, there is a need to correctly design the distance between the contacts of each of the first and the second switch and the magnetic coil, which complicates the manufacturing thereof.

In addition, because the first and the second mechanical contact switch are the normal excitation type, continuous current supply to the magnetic coil is required while keeping the first and the second switch turned on

(closed) . Therefore, a configuration using the first and the second switch of the normal excitation type as in the hybrid relay of Patent Document 2, needs to maintain the continuous power supply to the second switch as well upon a power supply to the load, which becomes an obstacle to the saving of power.

In fact, the semiconductor switch needs to be turned on only at the time of opening/closing the first switch to prevent arc generation causing, e.g., the contact fusion of the first switch, and the second switch does not need to be turned on once the first switch changes its state from OFF to ON. Since, however, the single magnetic coil is commonly used for opening and closing the first and the second switch in Patent Document 2, the second switch remains on as long as the first switch is on. Further, since the contacts of both of the first and the second switch are forced to make contact magnetically by the common magnetic coil, there is a need to generate the magnetic force exceeding a collective repulsive force of spring loads of the first and the second switch, resulting in increased current and power consumption.

Summary of the Invention

In view of the above, the present invention provides a hybrid relay which can realize a low power consumption by using a latch type mechanical contact switch installed on a power feed line to a load and operating a mechanical contact switch and a semiconductor switch connected in series therewith only when opening and closing the latch type mechanical contact switch. In accordance with a first aspect of the present invention, there is provided a hybrid relay including a first mechanical contact switch whose contact portion is opened and closed by a first driving unit; a second mechanical contact switch whose contact portion is opened and closed by a second driving unit operating independent of the first driving unit; and a semiconductor switch serially connected to the second mechanical contact switch.

Further, in the first aspect of the invention, the first mechanical contact switch is connected in parallel to the second mechanical contact switch and the semiconductor switch which are connected serially, on a power feed path to a load from a power source; the first mechanical contact switch is a latch type mechanical contact switch, wherein a current is supplied to the first driving unit when switching between an opened and a closed state of the contact portion of the first mechanical contact switch; and each of the second mechanical contact switch and the semiconductor switch becomes conductive before opening and closing of the contact portion of the first mechanical contact switch and becomes non-conductive after opening and closing of the contact portion of the first mechanical contact switch.

In the first aspect of the invention, when each of the second mechanical contact switch and the semiconductor switch is made conductive, the semiconductor switch becomes conductive after closing the contact portion of the second mechanical contact switch, and when each of the second mechanical contact switch and the semiconductor switch is made non-conductive, the contact portion of the second mechanical contact switch is opened after making the semiconductor switch non-conductive. In the first aspect of the present invention, the semiconductor switch has a zero-cross firing function which is made conductive when a voltage supplied from the AC power source becomes a center voltage. With this configuration, upon being conductive of the semiconductor switch, the inrush current flowing into the load from the power source can be constantly controlled without relation with a timing when the semiconductor switch becomes conductive.

In the first aspect of the present invention, when each of the second mechanical contact switch and the semiconductor switch is made non-conductive, the contact portion of the second mechanical contact switch is opened upon lapse of time equal to or longer than a half period of an AC voltage from the AC power source after making the semiconductor switch non-conductive. Therefore, in case a triac is used as the semiconductor switch, the contact portion of the second mechanical contact switch can be opened after the triac is certainly made non-conductive. Accordingly, supplying the power can be prevented from cutting off by the second mechanical contact switch.

In the first aspect of the present invention, when the contact portion of the first mechanical contact switch is closed: the semiconductor switch is made conductive after closing the contact portion of the second mechanical contact switch; the contact portion of the first mechanical contact switch is closed, while the second mechanical contact switch and the semiconductor switch is being conductive, respectively; and substantially simultaneously, the semiconductor switch is made non-conductive and the contact portion of the second mechanical contact switch is opened.

Further, when the contact portion of the first mechanical contact switch is opened: substantially simultaneously, the semiconductor switch becomes conductive and the contact portion of the second mechanical contact switch is closed; the contact portion of the first mechanical contact switch is opened, while the second mechanical contact switch and the semiconductor switch are being conductive, respectively; and then the contact portion of the second mechanical contact switch is opened after making the semiconductor switch non-conductive.

In the first aspect of the present invention, the second mechanical contact switch is a normal excitation type mechanical contact switch in which a current is constantly supplied to the second driving unit while the contact portion of the second mechanical contact switch is being closed. Further, the semiconductor switch includes a photocoupler having a light emitting element for generating an optical signal and the photocoupler is controlled to be conductive or non-conductive based on the optical signal of the light emitting element. In addition, the second driving unit and the light emitting element is serially connected, and, the second driving unit and the light emitting element may be driven by a common current when the second mechanical contact switch and the semiconductor switch are simultaneously made conductive.

In the first aspect of the present invention, when the second mechanical contact switch and the semiconductor switch, substantially at the same time, are switched from non-conductive state to conductive state, a first current is supplied to the light emitting element and the second driving unit; and when the second mechanical contact switch and the semiconductor, switch are made conductive while the second mechanical contact switch is in the conductive state, a second current smaller than the first current in magnitude may be supplied to the light emitting element and the second driving unit.

Further, a first current is supplied to the second driving unit when the contact portion of the second mechanical contact switch becomes closed, and, after the contact portion of the second mechanical contact switch is closed, a second current smaller than the first current in magnitude may be supplied to the second driving unit.

In the first aspect of the present invention, the second mechanical contact switch may be a latch type mechanical contact switch wherein a current is supplied to the second driving unit only when opening and closing the contact portion of the second mechanical contact switch.

In the first aspect of the present invention, a contact pressure of the second mechanical contact switch is smaller than a contact pressure of the first mechanical contact switch, and a distance between contacts in the second mechanical contact switch is smaller than a distance between contacts of the first mechanical contact switch.

In the first aspect of the present invention, the contact portion of the first mechanical contact switch includes contacts and a magnetic circuit in which, when the contacts are connected to flow a short-circuit current, an electromagnetic attractive force is formed in a direction in which the contacts of the first mechanical contact switch is closed.

In the first aspect of the present invention, the first mechanical contact switch is further provided with an auxiliary contact operating in conjunction with the contact portion of the first mechanical contact switch, and conduction or non-conduction of the contact portion of the first mechanical contact switch is detected based on the opening and the closing of the auxiliary contact.

In accordance with a second aspect of the present invention, there is provided a control terminal apparatus including hybrid relays according to the first aspect of the invention and performing the opening and the closing of the contact portions of the first mechanical contact switches for every predetermined number of hybrid relays when the opening and the closing of the contacts of the first mechanical contact switches of the hybrid relays is simultaneously switched. In accordance with the aspects of present invention, since the first and the second mechanical contact switch have first and second driving units, respectively, which are separated from each other and perform an opening and a closing of the contacts of the first mechanical contact switch and the second mechanical contact switch, and the first mechanical contact switch is configured in a latch type, each of the driving units may be driven only when the first mechanical contact switch is being switched. That is, the second mechanical contact switch and the semiconductor switch will be driven only when the first mechanical contact switch is being switched between opening and closing and a driving current may be supplied to the first driving unit of the first mechanical contact switch only when an opening and a closing of the first mechanical contact switch is being performed.

Accordingly, it is possible to reduce the power consumption in the hybrid relay and to prevent contact fusion at the time of opening/closing of the first mechanical contact switch by employing the second mechanical contact switch and the semiconductor switch.

Brief Description of the Drawings

The objects and features of the present invention will become apparent from the following description of preferred embodiments, given in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic circuit diagram of a hybrid relay in accordance with a first embodiment of the present invention; FIG. 2 is a timing chart showing a state transition of each part of the hybrid relay shown in FIG. 1;

FIG. 3 is a timing chart showing a relation between a state of each of various parts of the hybrid relay shown in FIG. 1 and an AC voltage from an AC power source; FIG. 4 is a schematic perspective view showing one example of a contact portion of a latch type mechanical contact switch;

FIG. 5 is a schematic cross sectional view showing a state when the contact portion having the configuration shown in FIG. 4 becomes conductive;

FIG. 6 is a schematic cross sectional view showing one example of a contact portion of a normal excitation type mechanical contact switch;

FIG. 7 is a schematic view illustrating one configuration example of a triac;

FIG. 8 is a schematic view illustrating another configuration example of the triac;

FIG. 9 is a schematic view illustrating still another configuration example of the triac; FIG. 10 is a schematic circuit diagram of a hybrid relay in accordance with a second embodiment of the present invention;

FIG. 11 is a timing chart showing a state transition of each of various parts of the hybrid relay shown in FIG. 10; FIG. 12 is a timing chart showing a state transition of each of various parts of a hybrid relay in accordance with a third embodiment of the present invention;

FIG. 13 is a schematic circuit diagram of a hybrid relay in accordance with a fourth embodiment of the present invention;

FIG. 14 is a timing chart showing a state transition of each of various parts of the hybrid relay shown in FIG. 13;

FIG. 15 is a schematic circuit diagram of a hybrid relay in accordance with a fifth embodiment of the present invention;

FIG. 16 is a timing chart showing a state transition of each of various parts of the hybrid relay shown in FIG. 15; FIG. 17 is a schematic circuit diagram of a hybrid relay in accordance with a sixth embodiment of the present invention; and

FIG. 18 is a timing chart showing a state transition of each of various parts of the hybrid relay shown in FIG. 17. Detailed Description of the Embodiments (First Embodiment)

A hybrid relay in accordance with a first embodiment of the present invention will be described with reference to drawings. FIG. 1 shows an internal configuration of a hybrid relay in accordance with this embodiment, and FIG. 2 is a timing chart showing a state transition of each of various parts of the hybrid relay shown in FIG. 1.

1. Configuration of Hybrid Relay

As shown in FIG. 1, the hybrid relay 1 of this embodiment is connected to respective one ends of an AC power source 2 and a load 3 connected in series to form a closed circuit together with the AC power source 2 and the load 3. That is, the supply and shutoff of a power from the

AC power source 2 to the load 3 is determined by the ON

(closed) /OFF (opened) of the hybrid relay 1. Here, it is assumed that the AC power source 2 is, for example, a commercial power source of 100V, and the load 3 is, e.g., a lighting fixture including a fluorescent lamp or an incandescent lamp, a fan or the like.

The hybrid relay 1 includes a terminal 10 connected to one end of the AC power source 2 whose the other end is connected to one end of the load 3; a terminal 11 connected to the other end of the load 3; a first mechanical contact switch 12 having a contact portion Sl, one end of which is connected to the terminal 10, while the other end of which is connected to the terminal 11; and a second mechanical contact switch 13 having a contact portion S2 whose one end is connected to a connection node between the terminal 10 and one end of the contact portion Sl. The hybrid relay 1 further includes a semiconductor switch 14 having a triac S3 whose Tl electrode is connected to the other end of the contact portion S2 while whose T2 electrode is connected to the terminal 11; and a signal processing circuit 16 for performing the ON (closed) / OFF (opened) control of each of the first and the second mechanical contact switch 12, 13 and the semiconductor switch 14.

Details of the circuit configuration of the hybrid relay 1 will be further described. In the hybrid relay 1, a serial circuit, which includes the contact portion S2 of the second mechanical contact switch 13 and the triac S3 of the semiconductor switch 14, and the contact portion Sl of the first mechanical contact switch 12 are connected in parallel between the terminals 10 and 11. The first mechanical contact switch is of a latch type, and includes a magnetic coil Ll which generates a magnetic force to switch the contact portion Sl to on (closed) and a magnetic coil L2 which generates a magnetic force to switch the contact portion Sl to off (opened) . Further, the second mechanical contact switch 13 is of a normal excitation type mechanical contact switch, and includes a magnetic coil L3 which generates a magnetic force to keep the contact portion S2 ON (closed) state. That is, the magnetic coils Ll and L2 are included in the first driving unit of the first mechanical contact switch 12, and the magnetic coil L3 is included in the second driving unit of the second mechanical contact switch 13.

Moreover, in the first mechanical contact switch 12, one end of the magnetic coil Ll is connected to a cathode electrode of a diode D3 whose anode electrode is connected to the signal processing circuit 16, while one end of the magnetic coil L2 is connected to a cathode electrode of a diode D4 whose anode electrode is connected to the signal processing circuit 16. The other ends of the magnetic coils Ll and L2 are connected to each other, and a connection node between the magnetic coils Ll and L2 is grounded, and is connected to the anode electrodes of the diodes Dl and D2, wherein the term "grounding" used herein and in the remaining embodiments represents the connection to a reference voltage in the hybrid relays. The cathode electrodes of the diodes Dl and D2 are connected to the cathode electrodes of the diodes D3 and D4 , respectively.

As describe above, the first mechanical contact switch 12 includes magnetic coils Ll and L2 connected in series, the diodes Dl and D2 whose anode electrodes are connected with each other, and the diodes D3 and D4 whose anode electrodes are connected to the signal processing circuit 16. The second mechanical contact switch 13 is made of a single magnetic coil L3 and a diode D5 connected in parallel therewith. Moreover, a connection node between one end of the magnetic coil L3 and an anode electrode of the diode D5 is grounded, and a connection node between the other end of the magnetic coil L3 and a cathode electrode of the diode D5 is connected to the signal processing circuit 16.

The semiconductor switch 14 includes the triac S3, a resistor Rl and a capacitor Cl connected in parallel between the T2 electrode of the triac 53 and a gate electrode G of thereof, a resistor R2 whose one end is connected to the Tl electrode of the triac S3, and a phototriac coupler 15 having a phototriac S4 whose Tl electrode is connected to the other end of the resistor R2. The phototriac coupler 15 is further provided with a light emitting diode LD whose anode electrode is connected to the signal processing circuit 16 via a resistor R3 and whose cathode electrode is grounded, and has a structure that an optical signal from the light emitting diode LD is inputted to the phototriac S4 whose T2 electrode is connected to the gate electrode G of the triac S3.

Further, the phototriac S4 is a semiconductor switching device with a zero-cross firing function. That is, once the phototriac S4 detects a center voltage (reference voltage) of AC voltage of the AC power source 2 on the T2 electrode side while receiving the optical signal from the light emitting diode LD, the triac S4 starts to be fired to be conductive (ON) . The triac S4 remains to be turned on until the center voltage is detected again after the light emitting diode LD is turned off.

2. Supply of Electric Power by Hybrid Relay

An operation of the supply and shutoff of a power from the AC power source 2 to the load 3 in the hybrid relay 1 so configured will be described below with reference to the timing chart shown in FIGs. 2 and 3. First, a description will be made for an operation of each part in the hybrid relay 1 when the signal processing circuit 16 is instructed to supply the power from the AC power source 2 to the load 3. As illustrated in the timing chart shown in FIG. 2, when a driving current is supplied from the signal processing circuit 16 to the magnetic coil L3, a magnetic force is generated by the magnetic coil L3. Then, the contact portion S2 in the second mechanical contact switch 13 is turned on. In the second mechanical contact switch 13, the diode D5 connected in parallel with the magnetic coil L3 functions as an anti-backflow diode for preventing a backflow of the current flowing in the magnetic coil L3.

In this way, when the contact portion S2 of the second mechanical contact switch 13 is turned on, the signal processing circuit 16 then applies a driving current to the light emitting diode LD. Accordingly, in the phototriac coupler 15, the light emitting diode LD emits light, and the phototriac S4 receives an optical signal resulting from the light emission. Since the phototriac S4 has the zero-cross firing function, the phototriac S4 becomes a conductive state (ON) when detecting that the AC voltage from the AC power source 2 is the center voltage (reference voltage) , as illustrated in the timing chart of FIG. 3. Also, FIG. 3 is a timing chart showing a relation between the AC voltage from the AC power source 2 and the operating state of each part of the first and the second mechanical contact switch 12 and 13 and the semiconductor switch 14.

By the conduction of the phototriac S4, an AC current from the AC power source 2 flows through the resistor 2 and the phototriac S4 to a parallel circuit of the resistor Rl and the capacitor Cl. Accordingly, the parallel circuit of the resistor Rl and the capacitor Cl operates to supply a current to the gate electrode of the triac S3, so that the triac S3 turns to be a conductive state (ON) . This allows the load 3 to be electrically connected to the AC power source 2 through the second mechanical contact switch 13 and the semiconductor switch 14 in the hybrid relay 1, and hence the power from the AC power source 2 is supplied to the load 3.

At this time, since the inrush current flows into the load 3 from the AC power source 2, a large current due to the inrush current also flows in the triac S3 and phototriac S4 each of which is in a conductive state. However, deviation in the amount of inrush current can be suppressed because there is no deviation between the timing of conduction of the phototriac S4 and a period of the AC voltage from the AC power source 2 owing to the zero-cross firing function of the phototriac S4. Further, although the inrush current also flows in the contact portion S2 of the second mechanical contact switch 13, it flows in a state where the contact portion S2 is closed. Therefore, there is no arc generation occurring while switching between the opening and the closing of the contact, and wearing of the contact portion caused by contact fusion or the like in the second mechanical contact switch 13 can be prevented.

In this way, after the power from the AC power source 2 is supplied to the load 3 by turning on the triac S3 in the semiconductor switch 14, the signal processing circuit 16 applies a pulse current serving as a driving current to the magnetic coil Ll via the diode D3. At this time, in the first mechanical contact switch 12, the diode Dl functions as an anti-backflow diode for preventing the backflow of the current flowing to the magnetic coil Ll, and the diode D4 prevents the current from flowing to the magnetic coil L2.

Accordingly, the pulse current flows through the magnetic coil Ll, and a magnetic force is temporarily generated to thereby turn on the contact portion Sl in the first mechanical contact switch 12. Moreover, since the first mechanical contact switch 12 is latch type, the contact portion Sl remains to be kept on even after the current supply to the magnetic coil Ll is ceased as illustrated in FIG. 2. In this manner, since the first mechanical contact switch 12 is turned on after a power feed path from the AC power source 2 to the load 3 is established by the second mechanical contact switch 13 and the semiconductor switch 14, it is possible to prevent the inrush current from flowing into the contact portion Sl. Therefore, contact bounce due to the inrush current which causes the contact fusion can be prevented in the first mechanical contact switch 12.

Then, when the power supply to the load 3 from the AC power source 2 via the contact portion Sl of the first mechanical contact switch 12 is started, the signal processing circuit 16 stops the supply of the driving current to the light emitting diode LD to thereby cutting off the power feed path in the semiconductor switch 14. As a result, the light emitting diode LD stops to radiate the light emission and an optical signal to the phototriac S4 stops to be radiated. Accordingly, the phototriac S4 stops its operation and turns into a non-conductive state (OFF) when the AC voltage from the AC power source 2 becomes a center voltage (reference voltage) . In addition, when the phototriac S4 is turned off, no current is supplied to the gate electrode of the triac S3. Accordingly, the triac S3 becomes non-conductive and the semiconductor switch 14 is turned off. After the semiconductor switch 14 is turned off, the signal processing circuit 16 stops supplying the driving current to the magnetic coil L3 of the second mechanical contact switch 13.

Then, because no magnetic force is generated by the magnetic coil L3 in the second mechanical contact switch 13 of the normal excitation type, the contact portion S2 is turned off.

Thus, since the second mechanical contact switch 13 is turned off after the semiconductor switch 14 is turned off, the contact portion S2 in the second mechanical contact switch 13 opens while there is no current flowing. Therefore, when the second mechanical contact switch 13 is turned OFF, arc generation between the contacts of the contact portion S2 can be prevented, and contact fusion in the second mechanical contact switch 13 can be prevented.

As described above, when the power is supplied from the AC power source 2 to the load 3, the signal processing circuit 16 can set the timings when the driving currents are supplied to the magnetic coil L3 and the light emitting diode LD, respectively, as shown in FIG. 3, thereby preventing contact wearing due to the contact fusion in the second mechanical contact switch 13. Provided that an AC voltage supplied from the AC power source 2 has a period of T, time t2 from the stopping of supply of the driving current to the light emitting diode LD until the stopping of supply of the driving current to the magnetic coil L3 is set to be longer than a half period T/2 of the AC voltage.

Consequently, after the triac S3 is completely turned off by turning off the phototriac S4 in the phototriac coupler 15, the second mechanical contact switch 13 is turned off. Further, since the phototriac S4 in the phototriac coupler 15 has the zero-cross firing function, deviation in the inrush current caused at the turning-on time of the triac S3 can be suppressed. Moreover, time tl from the start of the supply of the driving current to the magnetic coil L3 until the start of the supply of the driving current to the light emitting diode LD may be set to be longer than a half period T/2 of the AC voltage so as to suppress deviation in the inrush current more definitively.

3. Cutoff of Electric Power by Hybrid Relay

In the meantime, while the contact portion Sl of the first mechanical contact switch 12 is turned on and the power from the AC power source 2 to the load 3 is being supplied, when the signal processing circuit 16 is instructed to cut off the power to the load 3, the signal processing circuit 16 supplies the driving current to the magnetic coil L3 as illustrated in the timing chart of FIG. 2. Then, the contact portion S2 in the second mechanical contact switch 13 is turned on as in case that the power is supplied to the load 3. After a lapse of the time tl, the signal processing circuit 16 supplies the driving current to the light emitting diode LD. Then, the light emitting diode LD emits light and irradiates an optical signal to the phototriac S4. The phototriac S4 is conducted when the AC voltage from the AC power source 2 becomes a center voltage (reference voltage) , and, accordingly, the triac S3 becomes conductive, thereby turning on the semiconductor switch 14.

As a result, a power feed path passing through the first mechanical contact switch 12 and a power feed path passing through the second mechanical contact switch 13 and the semiconductor switch 14 are formed, as the power feed path from the AC power source 2 to the load 2, in the hybrid relay 1. That is, since the power feed path passing through the second mechanical contact switch 13 and the semiconductor switch 14 is established, a part of the current flowing in the load 3 flows in the second mechanical contact switch 13 and the semiconductor switch 14, thereby reducing the amount of current flowing in the first mechanical contact switch 12. Further, since the semiconductor switch 14 is turned on after turning on the second mechanical contact switch 13, the arc generation in the contact portion S2 can be avoided, thereby preventing the contact wearing due to the contact fusion in the second mechanical contact switch 13.

Thereafter, the signal processing circuit 16 applies a pulse current as a driving current, to the magnetic coil L2 via the diode D4, which temporarily excites the magnetic coil L2, thereby turning off the contact portion Sl. At this time, because the contact portion Sl opens in a state where the amount of current becomes smaller, the arc generation can be suppressed and the contact wearing caused by the contact fusion in the first mechanical contact switch 12 can be prevented.

Further, in the first mechanical contact switch 12, the diode D2 functions as an anti-backflowing diode for preventing the backflow of the current flowing in the magnetic coil L2, and the diode D3 prevents the current from flowing to the magnetic coil Ll.

In this way, when the contact portion Sl in the first mechanical contact switch 12 is turned off, first, the signal processing circuit 16 stops supplying the driving current to the light emitting diode LD. Accordingly, the light emitting diode LD stops radiating an optical signal, and hence the phototriac S4 is turned off when the AC voltage from the AC power source 2 is the center voltage (reference voltage) . The triac S3 becomes non-conductive when the phototriac S4 becomes nonconductive so that the semiconductor switch 14 is turned off. Therefore, the power feed path to the load 3 from the AC power source 2 is cut off, thereby stopping the supply of the power to the load 3 from the AC power source 2. Further, after a lapse of the time t2 from stopping the supply of the driving current to the light emitting diode LD, the signal processing circuit 16 stops the supply of driving current to the magnetic coil L3. That is, after the semiconductor switch 14 is turned off, excitation of the magnetic coil L3 is stopped. Accordingly, the contacts of the contact portion S2 are opened and the second mechanical contact switch 13 is turned off. At this time, since the semiconductor switch 14 is already turned off and no current flows in the second mechanical contact switch 13, there is no arc generation even if the contacts of the contact portion S2 are opened and the wearing of the contacts can be prevented.

4. Configuration Example of Contact Portion Sl in First Mechanical Contact Switch 12

A configuration example of the contact portion Sl of the first mechanical contact switch 12 provided in the above-described hybrid relay 1 will be described with reference to FIG. 4. As illustrated in FIG. 4, the contact portion Sl has a fixed contact terminal 101 whose one end is fixed, and a movable contact terminal 102 whose one end is fixed and the other end of which is displaced by a driving member (not shown) . Each of the fixed contact terminal 101 and the movable contact terminal 102 is formed of a conductive material, and further the movable contact terminal 102 is formed of a flexible conductive material such that the other end of the movable contact terminal 102 is displaced when it is pressed by the not shown driving member. Further, a fixed contact 103 is convexly provided on a surface facing to the movable contact terminal 102 at the other end of the fixed contact terminal 101. A movable contact 104 is convexly provided on a surface facing to the fixed contact terminal 101 at the other end of the movable contact terminal 102.

In addition, a fixed metal piece 105 is installed between the one end of the fixed contact terminal 101 and the fixed contact 103. The fixed metal piece 105 has a U- shaped cross section such that it covers the opposite surface to the surface on which the fixed contact 103 is provided and both side surfaces of the fixed contact terminal 101.

A pressing portion 107 is provided on the surface of the movable contact terminal 102 opposite to the surface where the movable contact 104 is installed. The pressing portion 107 extends from the other end of the movable contact terminal 102 toward one end of the fixed contact terminal 101 so as to extend along an extension direction of the fixed contact terminal 101. Further, a movable metal piece 106 is installed on the pressing portion 107 at a position which is contactable with both ends of the fixed metal piece 105 between the fixed contact terminal 101 and the pressing portion 107 of the movable contact terminal 102. Both ends of the fixed metal piece 105 are projected toward the movable metal piece 106 from the surface of the fixed contact terminal 101 facing the movable metal piece 106. Each of the fixed metal piece

105 and the movable metal piece 106 is formed of a magnetic material.

In the contact portion Sl so configured, when the movable contact terminal 102 is pressed by the driving member (not shown) , the other end of the movable contact terminal 102 is displaced toward the other end of the fixed contact terminal 101, and as illustrated in FIG. 5, the movable contact 104 contacts with the fixed contact 103 to thereby become conductive. At this time, since the movable metal piece 106 is pressed by the pressing portion 107 of the movable contact terminal 102, the movable metal piece

106 is displaced toward the fixed contact terminal 101, along with the movable contact 104 on the movable contact terminal 102.

Therefore, when the fixed contact 103 and the movable contact 104 are in contact with each other and the contact portion Sl becomes conductive, the fixed metal piece 105 and the movable metal piece 106 are made to contact each other, so that a magnetic body is formed around the fixed contact terminal 101 by surrounding the outer periphery thereof. That is, the magnetic body is formed in a ring shape by the fixed metal piece 105 and the movable metal piece 106 to surround the current flowing through the fixed contact terminal 101. As a result, an induced magnetic flux is generated in the fixed metal piece 105 and the movable metal piece 106 concentrically about the current flowing through the fixed contact terminal 101. By the induced magnetic flux thus produced, the fixed and the movable metal piece 105 and 106 attract each other.

Further, in the contact portion Sl, when the fixed contact 103 and the movable contact 104 are contacted with each other and become conductive, currents flowing through the fixed contact 103 and the movable contact 104 are in antiparallel to each other, and thereby generating a repulsive magnetic force between the fixed contact terminal 101 and the movable contact terminal 102. With the configuration as illustrated in FIG. 4, since there are provided the fixed metal piece 105 and the movable metal piece 106, an attractive magnetic force is generated by the fixed metal piece 105 and the movable metal piece 106, which in turn cancels the repulsive magnetic force caused by antiparallel currents flowing through the fixed contact 103 and the movable contact 104. Consequently, the contact bounce in the contact portion Sl can be suppressed, the first driving unit for displacing the movable contact terminal 102, including the magnetic coils Ll and L2, can be made in smaller size, and the first mechanical contact switch 12 itself can also be made smaller.

5. Configuration Example of Contact Portion S2 in Second Mechanical Contact Switch 13

Next, a configuration example of the contact portion S2 of the second mechanical contact switch 13 will be described with reference to the drawings. The distance between contacts of the contact portion S2 of the second mechanical contact switch 13 is shorter than that of the contact portion Sl of the first mechanical contact switch 12, and also the contact pressure thereof is smaller than that of the contact portion Sl of the first mechanical contact switch 12.

Accordingly, the number of windings of the magnetic coil L3 of the second mechanical contact switch 13 can be reduced, and the magnetic coil L3 can be made smaller. Further, the contact portion S2 can also be made smaller by using the configuration disclosed in Japanese Patent Application No. 2007-166523 by the present applicant. Therefore, the second mechanical contact switch 13 itself an be made smaller.

A configuration example of the contact portion S2 of the second mechanical contact switch 13 is shown in FIG. 6. Although the example shown in FIG. 6 will be described below, another configuration may be used in order to make it smaller. For example, in the configurations as disclosed in Japanese Patent Application No. 2007-166523, the magnetic coil L3 can be omitted by constituting the second driving unit with a piezoelectric element or a shape memory alloy.

First, the configuration of the contact portion S2 shown in FIG. 6 will be described below. The contact portion S2 shown in FIG. 6 includes two fixed contact terminals 201 and 202 formed of a conductive material, a movable contact member 203 formed of a conductive material which can be made to contact with the two fixed contact terminals 201 and 202, and a driving member 204 formed of an insulating material, for pushing the movable contact member 203 toward the fixed contact terminals 201 and 202. Each of the fixed contact terminals 201 and 202 and the movable contact member 203 are formed of a conductive plate and the fixed contact terminals 201 and 202 are arranged on the bottom surface of a housing 205 such that they do not contact with each other. The movable contact member 203 is supported on the housing 205 at its four corners where a bent portion 206 of an approximately inversed U-shape is provided. Thus, when the movable contact member 203 is not pressed by the driving member 204, it is arranged at a position being apart from the fixed contact terminals 201 and 202 in a hollow inside the housing 205. Further, because the housing 205 is formed of an insulating material, when there is no pressure applied from the driving member 204, the fixed contact terminals 201 and 202 are insulated from the movable contact member 203.

With this configuration of the contact portion S2, when the movable contact member 203 is pressed by the driving member 204, the center portion of the movable contact member 203 is displaced toward the fixed contact terminals 201 and 202 because of the flexibility of the bent portion 206. Accordingly, the movable contact member 203 is brought into contact with the fixed contact terminals 201 and 202, and bridges over the fixed contact terminals 201 and 202. Therefore, the fixed contact terminal 201 can be electrically connected to the fixed contact terminal 202 via the movable contact member 203, thereby bringing the contact portion S2 into a conductive state.

6. Configuration Example of Triac S3 and Phototriac S4

In addition, the configurations of the triac S3 and the phototriac S4 will be described below with reference to FIGs. 7 to 9. Although the following description will be made with respect to the configuration of the triac S3 based on an internal structure of the triac S3 shown in FIGs. 7 to

9, the phototriac S4 may be configured similarly except for the configuration of a gate electrode. First, the triac S3 shown in FIG. 7 includes a semiconductor chip 300 of a bidirectionally controlled rectifier type. The semiconductor chip 300 is provided with a Tl electrode 301 and a gate electrode 302 on a front surface and a T2 electrode (not shown) on a back surface. This semiconductor chip 300 is also connected to a lead frame 304 by soldering, so that the entire back surface of the semiconductor chip 300 having the T2 electrode is in contact with a surface of the lead frame 304 including a second lead terminal 304a. Further, the lead frame 304 whose surface is connected to the T2 electrode of the back surface of the semiconductor chip 300 is joined onto a stay 303 having a heat dissipation unit 303a by soldering, thereby dissipating heat from the back surface (T2 electrode) side of the semiconductor chip 300 at the time of current conduction. Further, in the surface side of the semiconductor chip 300, one ends of two linear wires 301b are ultrasonically connected to the Tl electrode 301, and the other ends of them are ultrasonically connected to a first lead terminal 301a. And, one end of a linear wire 302b is ultrasonically connected to the gate electrode 302, and the other end of it is ultrasonically connected to a gate lead terminal 302a.

Additionally, the Tl electrode 301 is formed approximately in a rectangular shape with one corner cut off, on the surface of the semiconductor chip 300, and the gate electrode 302 is provided in that corner, whose outer peripheral portion which is a boundary with the Tl electrode 301, is insulated from the Tl electrode 301.

As described above, the gate electrode 302 is connected with one linear wire 302b and the Tl electrode 301 is connected with two linear wires 301b. Therefore, the connection area in the Tl electrode 301 is wider than the connection area in the gate electrode 302. Further, the connection area may be further widened by forming a plurality of connections between the two respective linear wires 301b and the Tl electrode 301 by using an ultrasonic connection.

Further, since the back side of the semiconductor chip 300 is surface-connected with the lead frame 304, the connection area with the lead frame 304 in the T2 electrode (not shown) is wider than the connection area with the linear wire 302b in the gate electrode 302.

Therefore, even if a inrush current flows in the triac S3, the current is dispersed in a joining portion of the Tl electrode 301 and T2 electrode 302 of the triac S3 because the area of the joining portion is large. Accordingly, insulation breakdown in the tirac S3 can be prevented due to a local current concentration, which leads into improving resistance against the inrush current.. Further, in order to prevent the insulation breakdown caused by the local current concentration, the Tl electrode 301 may be connected with three or more linear wires 301b, or connected with a ribbon- shaped wire having a cross-sectional area larger than that of the linear wires 301b.

Further, a heat dissipation block 310 having a cross section of a roughly trapezoidal shape may be joined to the Tl electrode 301 connected with the two linear wires 301b, as shown in FIG. 8, thereby improving the heat dissipation efficiency at the Tl electrode of the triac S3. Therefore, even when a inrush current flows in the triac S3, a temperature rise caused by the inrush current can be suppressed, and as a result, resistance against the inrush current of the triac S3 can be enhanced. Moreover, as in FIG. 9, in order to widen the junction area in the Tl electrode 301 and improve the heat dissipation effect, a lead frame 301c having a first lead terminal 301a, instead of the linear wires 301b, may be connected to the Tl electrode 301 by soldering.

(Second Embodiment)

A hybrid relay in accordance with a second embodiment of the present invention will be described with reference to the drawings. FIG. 10 is a schematic circuit diagram showing an internal configuration of the hybrid relay of this embodiment, and FIG. 11 is a timing chart showing a state transition of each part of the hybrid relay shown in FIG. 10. Further, in the hybrid relay of Fig. 10, like parts to those of the configuration of the hybrid relay of FIG. 1 are denoted by like reference numerals, and a detailed description thereof will be omitted.

With the hybrid relay Ia of this embodiment, an amount of a driving current can be reduced, compared to the hybrid relay 1 (see FIG. 1) of the first embodiment, by serially connecting a magnetic coil L3 of a second mechanical contact switch 13 and a light emitting diode LD of a phototriac coupler 15 included in a part of a semiconductor switch 14, as shown in Fig. 10. Specifically, a signal processing circuit 16a, instead of the signal processing circuit 16 in the hybrid relay 1, is provided, and one end of the magnetic coil L3 is connected to one end of a resistor R3. The other end of the resistor R3 is connected to the signal processing circuit 16a and an anode electrode of the light emitting diode LD is connected to the other end of the magnetic coil L3.

Further, a diode D5 is connected between both ends of the magnetic coil L3 and functions as an anti-backflow device in the magnetic coil L3. A cathode electrode of the diode D5 is connected to the resistor R3, and an anode electrode thereof is connected to the anode electrode of the light emitting diode LD.

The hybrid relay Ia further includes resistors R4 and R5, and npn-type transistors TrI and Tr2. One end of the resistor R4 is connected to a connection node of the anode electrode of the light emitting diode LD and the magnetic coil L3, and one end of the resistor R5 is connected to a cathode electrode of the light emitting diode LD. The other ends of the resistors R4 and R5 are connected to collector electrodes of the npn-type transistors TrI and Tr2, respectively, and emitter electrodes of the npn-type transistors TrI and Tr2 are grounded. Further, a control signal is applied from the signal processing circuit 16a to base electrodes of the transistors TrI and Tr2. The other components are identical to those of the hybrid relay 1 of the first embodiment, so a detailed description thereof will be omitted.

The operation of the hybrid relay Ia as configured above will be described below with reference to the timing charts shown in FIGs. 2 and 11. In the hybrid relay Ia, like the hybrid relay 1 of the first embodiment, timings for supplying the driving currents to the magnetic coils Ll to L3 and the light emitting diode LD, ON/OFF timings of respective contact portions Sl and S2, and ON/OFF timings of respective triac S3 and phototriac S4 correspond to the timings in the timing chart shown in FIG. 2. Specifically, when a power is supplied to a load 3 by an AC power source 2, first, a driving current is applied to the magnetic coil L3, and the contact portion S2 of the second mechanical contact switch 13 is turned on. Then, the light emitting diode LD is made to emit light, and the phototriac S4 and the triac S3 become conductive to thereby turn on the semiconductor switch 14. In this manner, by applying a driving current of pulse current to the magnetic coil Ll in a state where the second mechanical contact switch 13 and the semiconductor switch 14 are turned on, the contact portion Sl of the first mechanical contact switch 12 is switched on. After that, the driving current to the light emitting diode LD is stopped and the phototriac S4 and the triac S3 are not made conductive to turn the semiconductor switch 14 off. Then, the supply of the driving current to the magnetic coil L3 is stopped and the contact portion S2 of the second mechanical contact switch 13 is turned off.

Meanwhile, when the supply of the power to the load 3 from the AC power source 2 is shut off, the driving current is applied to the magnetic coil L3, the second mechanical contact switch 13 is turned on, and then the light emitting diode LD is made to emit light to turn the semiconductor switch 14 on in the same manner as above. And, by applying the driving current of the pulse current to the magnetic coil L2, the contact portion Sl of the first mechanical contact switch 12 is switched off. Afterwards, the driving current to the light emitting diode LD is stopped and the semiconductor switch 14 is turned off, and then the supply of the driving current to the magnetic coil L3 is stopped and the second mechanical contact switch 13 is turned off. At this time, as illustrated in the timing chart shown in FIG. 11, the hybrid relay Ia of this embodiment can determine the timings for applying the driving currents to the magnetic coil L3 and the light emitting diode LD, respectively, by determining the timings at which a control signal is applied to the base electrodes of the transistors TrI and Tr2. Hereinafter, the relationship between output timings of a control signal to the base electrodes of the transistors TrI and tr2 by the signal processing circuit 16a and generation timings of the driving currents to the magnetic coil L2 and the light emitting diode LD will be described with reference to the timing chart of FIG. 11.

As illustrated in the timing chart of FIG. 11, the signal processing circuit 16a first applies a control signal to the base electrode of the transistor TrI such that the transistor TrI is brought into a conductive state (ON) , thereby driving a serial circuit including the resistors R3 and R4 and the magnetic coil L3. That is, the signal processing circuit 16a applies the driving current only to the magnetic coil L3 by turning the transistor TrI on. Accordingly, as described above, the contact portion S2 of the second mechanical contact switch 13 is turned on.

In addition, when time tl is elapsed after the transistor TrI is turned on, the signal processing circuit 16a stops to supply a control signal to the gate electrode of the transistor TrI and starts to supply a control signal to the gate electrode of the transistor Tr2. That is, by turning the transistor TrI off and turning the transistor Tr2 on, a serial circuit including the resistors R3 and R5, the magnetic coil L3, and the light emitting diode LD is driven. Accordingly, a driving current is applied from the signal processing circuit 16a to each of the magnetic coil L3 and the light emitting diode LD connected in series. Thus, with the contact portion S2 of the second mechanical contact switch 13 being turned on, the triac S3 of the semiconductor switch 14 can be turned on.

Further, unlike the hybrid relay 1 of the first embodiment, since the magnetic coil L3 and the light emitting diode LD are serially connected, the driving current flowing through each of them is commonly used. Therefore, the amount of driving current while the magnetic coil L3 and the light emitting diode LD are simultaneously driven can be reduced, compared to the hybrid relay 1 of the first embodiment in which the magnetic coil L3 and the light emitting diode LD are connected in parallel, which suppresses power consumption.

And, after applying the driving current to the light emitting diode LD and turning the triac S3 of the semiconductor switch 14 on, as described above, the signal processing circuit lβa supplies a driving current of a pulse current to one of the magnetic coils Ll and L2. Specifically, in case of supplying a power to the load 3, a driving current is supplied to the magnetic coil Ll and the contact portion Sl of the first mechanical contact switch 12 is switched on, while in case of shutting off the power to the load 3, the driving current is supplied to the magnetic coil L2 and the contact portion Sl of the first mechanical contact switch 12 is switched off. In this way, when the ON/OFF of the first mechanical contact switch 12 is switched, the signal processing circuit 16a stops supplying the control signal to the gate electrode of the transistor Tr2 and starts to supply the control signal to the gate electrode of the transistor TrI. That is, by turning the transistor Tr2 off and turning the transistor TrI on, the supply of the driving current to the light emitting diode LD is stopped and the triac S3 of the semiconductor switch 14 is turned off. At this time, since the driving current is continuously supplied to the magnetic coil L3 by the turn-on of the transistor TrI, the contact portion S2 of the second mechanical contact switch 13 is kept ON. And, when time t2 is elapsed after the turn-off of the transistor Tr2, the signal processing circuit 16a stops to supply the control signal to the gate electrode of the transistor TrI. Accordingly, by the turn-off of the transistor TrI, the supply of a driving current to the magnetic coil L3 is stopped and the second mechanical contact switch 13 is turned off.

With this embodiment in which the magnetic coil L3 and the light emitting diode LD are serially connected, if the second mechanical contact switch 13 and the semiconductor switch 14 are simultaneously turned on, a common driving current can be made to flow into the magnetic coil L3 and the light emitting diode LD. Therefore, compared to the case where the magnetic coil L3 and the light emitting diode LD are connected in parallel, the amount of the driving current to be supplied from the signal processing circuit 16a can be reduced, which leads to a reducing power consumption of the hybrid relay Ia.

Further, in this embodiment, resistance values of the resistors R4 and R5 may be set so that a current value flowing in the magnetic coil L3 when the transistor Tr2 is turned on is smaller than a current value flowing in the magnetic coil L3 when the transistor TrI is turned on. That is, when the resistance values of the resistors R4 and R5 are Rr4 and Rr5, respectively, a drop voltage of the light emitting diode D5 is Vd, and current flowing in the magnetic coil when the transistor TrI is turned on is II, the resistance value Rr5 of the resistor R5 is set larger than the resistance value Rr4-Vd/Il. By setting the resistance values of the resistors R4 and R5 as described above, when the transistor TrI is turned on, a sufficiently large current flows in the magnetic coil L3 and the second mechanical contact switch 13 is turned on. Then, when the semiconductor switch 14 is turned on in the state that the second mechanical contact switch 13 is on, the transistor Tr2 can be turned on with a smaller current compared to when the second mechanical contact switch 13 is switched on. Accordingly, in the timing chart of FIG. 11, the total amount of the driving current for operating the transistors TrI and Tr2 can be suppressed, and a low power consumption can be achieved.

(Third Embodiment)

A hybrid relay in accordance with a third embodiment of the present invention will be described with reference to the drawings. An internal configuration of the hybrid relay of this embodiment corresponds to the configuration of the second embodiment shown in FIG. 10. FIG. 12 is a timing chart showing a state transition of each part of the hybrid relay of this embodiment. In this embodiment, although the hybrid relay Ia having the same configuration as the second embodiment is used, the transistors TrI and Tr2 are driven, respectively, at different timings for the ON/OFF switch of the first mechanical contact switch 12, unlike the second embodiment. The operation of the hybrid relay Ia of this embodiment will be described below with reference to the timing chart shown in FIG. 12.

As illustrated in the timing chart shown in FIG. 12, when a power is supplied to the load 3, first, the signal processing circuit 16a turns the transistor TrI on to supply a driving current to the magnetic coil L3 and, accordingly, turns the contact portion S2 of the second mechanical contact switch 13 on as in the second embodiment. Thereafter, the signal processing circuit 16a supplies the driving currents to the magnetic coil L3 and the light emitting diode LD by tuning the transistor TrI off and turning on the transistor Tr2 substantially at the same time. Accordingly, with the contact portion S2 of the second mechanical contact switch 13 being turned on, the triac S3 of the semiconductor switch 14 is turned on.

In this way, when the triac S3 in the semiconductor switch 14 is turned on and the power from the AC power source 2 is supplied to the load 3, the signal processing circuit 16a supplies a driving current of a pulse current to the magnetic coil Ll and turns the contact portion Sl of the first mechanical contact switch 12 on. Further, after the supply of power to the load 3 from the AC power source 2 is started through the contact portion Sl of the first mechanical contact switch 12, the signal processing circuit 16a stops supplying the driving currents to the magnetic coil L3 and the light emitting diode LD by turning the transistor Tr2 off in order to cut off a power feed path in the semiconductor switch 14. That is, after the turn-on of the first mechanical contact switch 12 to supply the power to the load 3, a period for supplying a driving current only to the magnetic coil L3 by turning on the transistor TrI is excluded in this embodiment unlike in the second embodiment. Therefore, in accordance with the power control of this embodiment carried out when starting to supply the power to the load 3, it is possible to reduce the power consumption by the amount corresponding to the driving current supplied to the magnetic coil L3 by turning on the transistor TrI , compared to the second embodiment.

On the other hand, when the supply of power to the load 3 from the AC power source 2 is cut off, unlike the second embodiment, the signal processing circuit 16a firstly turns the transistor Tr2 on to supply a driving current to each of the magnetic coil L3 and the light emitting diode LD, thereby turning on the contact portion S2 of the second mechanical contact switch 13 and the triac S3 of the semiconductor switch 14. Thus, when a power feed path passing through the contact portion S2 of the second mechanical contact switch 13 and the triac S3 of the semiconductor switch 14 is established, the signal processing circuit 16a supplies a driving current of a pulse current to the magnetic coil L2, and turns the contact portion Sl of the first mechanical contact switch 12 off.

When the power feed path passing through the contact portion Sl of the first mechanical contact switch 12 is cut off, the signal processing circuit 16a stops supplying the driving current to the light emitting diode LD and turns off the triac S3 of the semiconductor switch 14 by turning the transistor Tr2 off and turning the transistor TrI on substantially at the same time, as in the second embodiment.

Accordingly, the supply of the power to the load 3 from the

AC power source 2 is cut off. After that, the signal processing circuit 16a stops to supply the driving current to the magnetic coil L3 and turns off the contact portion S2 of the second mechanical contact switch 13 by turning off the transistor TrI.

That is, before the turn-on of the semiconductor switch 14 to cut off the power to the load 3, a period for turning on only the second mechanical contact switch 12 is excluded in this embodiment unlike in the second embodiment.

Therefore, in accordance with the power control of this embodiment carried out when starting to cut off the power to the load 3, it is possible to reduce the power consumption by an amount corresponding to the driving current supplied to the magnetic coil L3 by turning on the transistor TrI, compared to the second embodiment.

(Fourth Embodiment) A hybrid relay in accordance with a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 13 is a schematic circuit diagram showing an internal configuration of the hybrid relay of this embodiment, and FIG. 14 is a timing chart showing a state transition of each part of the hybrid relay shown in IG. 13. Further, in the hybrid relay shown in FIG. 13, like parts to those of the configuration of the hybrid relay shown in FIG. 10 are denoted by like reference numerals, and a detailed description thereof will be omitted.

As illustrated in FIG. 13, the hybrid relay Ib of this embodiment has a configuration in which a serial circuit including a resistor R5a and a transistor Tr2a is further connected to a cathode electrode of the light emitting diode LD in the hybrid relay Ia shown in FIG. 10. Further, one end of the resistor R5a is connected to a connection node of the cathode electrode of the light emitting diode LD and a resistor R5 and the other end of the resistor R5a is connected to a collector of the npn transistor Tr2a whose emitter electrode is grounded. Moreover, the hybrid relay Ib has a signal processing circuit 16b instead of the signal processing circuit 16a, which applies current signals to gate electrodes of transistor TrI, Tr2, and Tr2a, and magnetic coils Ll and L2.

In the hybrid relay Ib configured as above, the relationship between resistance values Rr5 and Rr5a of the resistors R5 and R5a connected to the light emitting diode LD is Rr5 < Rr5a. Further, when a resistance value of the resistor R4 is Rr4, a drop voltage of the light emitting diode D5 is Vd, and a current flowing through the magnetic coil L3 when the transistor TrI is turned on is II, the resistance value Rr5 of the resistor R5 is set to a resistance value Rr4-Vd/Il. By setting the resistance values Rr5 and Rr5a of the resistors R5 and R5a as above, the current value flowing through the magnetic coil L3 when the transistor TrI is turned on and the current value flowing through the magnetic coil L3 when the transistor Tr2 is turned on can be made equal. Further, the current flowing through the magnetic coil L3 when the transistor Tr2a is turned on can be made smaller.

Hereinafter, the operation of the hybrid relay Ib of this embodiment will be described with reference to the timing chart shown in FIG. 14. As illustrated in the timing chart shown in FIG. 14, when a power is supplied to the load 3, the signal processing circuit 16b firstly turns the transistor TrI on to supply a driving current to the magnetic coil L3 and turn on the contact portion S2 of the second mechanical contact switch 13, as in the third embodiment. Since the magnetic coil L3 can be driven by a driving current having a current amount required to maintain the contact portion S2 in the ON state after turning on the contact portion S2 by applying a sufficient driving current to the magnetic coil L3, the current amount flowing in the magnetic coil L3 can be reduced.

Therefore, unlike in the third embodiment, the signal processing circuit 16b supplies the magnetic coil L3 and the light emitting diode LD with a driving current having a current amount smaller than that when the transistor TrI is turned on, by turning off the transistor TrI and turning on the transistor Tr2a substantially at the same time.

Accordingly, the triac S3 of the semiconductor switch 14 is turned on, with the contact portion S2 of the second mechanical contact switch 13 being turned on. In this manner, when the power is supplied from the AC power source 2 to the load 3, the signal processing circuit 16b supplies a driving current of a pulse current to the magnetic coil Ll and turns on the contact portion Sl of the first mechanical contact switch 12, as in the third embodiment. Thereafter, in order to cut off a power feed path in the semiconductor switch 14, the signal processing circuit 16b stops supplying the driving current to the magnetic coil L3 and the light emitting diode LD by turning off the transistor Tr2a.

On the other hand, when the power to the load 3 from the AC power source 2 is cut off, as in the third embodiment, the signal processing circuit 16b firstly turns on the transistor Tr2 to supply a driving current to the magnetic coil L3 and the light emitting diode LD. In this way, when the contact portion S2 of the second mechanical contact switch 13 and the triac S3 of the semiconductor switch 14 are turned on, then the driving current flowing in the magnetic coil L3 can be reduced. Thus, the signal processing circuit 16b substantially simultaneously turns off the transistor Tr2 and turns on the transistor Tr2a. In this way, a smaller driving current can be supplied to the magnetic coil L3 and the light emitting diode LD, in the state that the contact portion S2 of the second mechanical contact switch 13 and the triac S3 of the semiconductor switch 14 are kept on. Then, the signal processing circuit 16b supplies a driving current of a pulse current to the magnetic coil L2 to turn off the contact portion Sl of the first mechanical contact switch 12.

When the power feed path passing through the contact portion Sl of the first mechanical contact switch 12 is cut off, the signal processing circuit 16b stops supplying the driving current to the light emitting diode LD and turns off the triac S3 of the semiconductor switch 14, by substantially simultaneously turning off the transistor Tr2a and turning on the transistor TrI. Accordingly, the power to the load 3 from the AC power source 2 is cut off. After that, the signal processing circuit 16b stops supplying the driving current to the magnetic coil L3 and turns off the contact portion S2 of the second mechanical contact switch 13 by turning off the transistor TrI.

As above, in this embodiment, while the contact portion S2 of the second mechanical contact switch 13 is maintained in the ON state, the amount of the driving current supplied to the magnetic coil L3 can be decreased, compared to that supplied to the magnetic coil L3 when the contact portion S2 of the second mechanical contact switch 13 is turned on. Therefore, the power consumption can be further reduced, compared to the third embodiment, by the use of the hybrid relay Ib of this embodiment.

(Fifth Embodiment)

A hybrid relay in accordance with a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 15 is a schematic circuit diagram showing an internal configuration of a hybrid relay of this embodiment, and FIG. 16 is a timing chart showing a state transition of each part of the hybrid relay shown in FIG. 15. Further, in the hybrid relay shown in FIG. 15, like parts to those of the configuration of the hybrid relay shown in FIG. 13 are denoted by like reference numerals, and a detailed description thereof will be omitted.

As illustrated in FIG. 15, the hybrid relay Ic of this embodiment has a configuration in which a serial circuit including a resistor R4a and a transistor TrIa is further connected,to a connection node of a magnetic coil L3 and a resistor R4 , in addition to the configuration of the hybrid relay Ib (see FIG. 13) . Specifically, one end of the resistor R4a is connected to the connection node of the magnetic coil L3 and the resistor R4 , and a collector of the npn type transistor TrIa whose emitter electrode is grounded is connected to the other end of the resistor R4a. In addition, the hybrid relay Ic includes a signal processing circuit 16c for applying a current signal to the gate electrodes of the transistors TrI, TrIa, Tr2, and Tr2a and the magnetic coils Ll and L2, respectively, instead of the signal processing circuit 16a.

Further, resistance values Rr4 and Rr4a of the resistors R4 and R4a are expressed by Rr4<Rr4a similar to the relationship between the resistance values Rr5 and Rr5a of the resistors R5 and R5a. That is, a current value flowing in the magnetic coil L3 when the transistor TrI is turned on and a current value flowing in the magnetic coil L3 when the transistor Tr2 is turned on are made equal to each other, and a current value flowing in the magnetic coil L3 when the transistor TrIa is turned on and a current value flowing in the magnetic coil L3 when the transistor Tr2a is turned on are made equal to each other. And, the current value flowing in the magnetic coil L3 when either of the transistors TrIa and Tr2a is turned on can be made smaller, compared to the current value flowing in the magnetic coil L3 when either of the transistors TrI and Tr2 is turned on.

The operation of the hybrid relay Ic will be described below with reference to the timing chart shown in FIG. 16. As illustrated in the timing chart shown in FIG. 16, when a power is supplied to the load 3, first, the signal processing circuit 16c turns the transistor TrI on to turn on the contact portion S2 of the second mechanical contact switch 13, as in the fourth embodiment. Then, the signal processing circuit 16c substantially simultaneously turns off the transistor TrI and turns on the transistor Tr2a, in order to supply a driving current having a smaller current amount than that applied when the transistor TrI is turned on. Accordingly, the triac S3 of the semiconductor switch 14 is turned on in the state that the contact portion S2 of the second mechanical contact switch 13 is turned on.

In this way, when the power from the AC power source 2 is supplied to the load 3, the signal processing circuit 16c supplies a driving current of a pulse current to the magnetic coil Ll and turns on the contact portion Sl of the first mechanical contact switch 12. After that, the signal processing circuit stops to supply the driving current to the magnetic coil L3 and the light emitting diode LD by turning off the transistor Tr2a.

On the other hand, when the supply of the power to the load 3 from the AC power source 2 is cut off, the signal processing circuit 16c firstly turns the transistor Tr2 on to turn on the contact portion S2 of the second mechanical contact switch 13 and the triac S3 of the semiconductor switch 14. After that, the signal processing circuit 16c turns off the transistor Tr2 and turns on the transistor Tr2a, substantially at the same time. Further, while the contact portion S2 of the second mechanical contact switch 13 and the triac S3 of the semiconductor switch 14 are being turned on, the signal processing circuit 16c supplies a driving current of a pulse current to the magnetic coil L2 to turn off the contact portion Sl of the first mechanical contact switch 12.

When a power feed path passing through the contact portion Sl of the first mechanical contact switch 12 is cut off, the signal processing circuit 16c substantially simultaneously turns off the transistor Tr2a and turning of the transistor TrIa, unlike in the fourth embodiment. Accordingly, the supply of driving current to the light emitting diode LD is stopped and the triac S3 of the semiconductor switch 14 is turned off. With this embodiment, when the supply of power to the load 3 from the AC power source 2 is cut off, the driving current supplied to the magnetic coil L3 can be also reduced as in case the transistor Tr2a is turned on. Therefore, the power consumption can be further reduced compared to the fourth embodiment. Afterwards, the signal processing circuit 16c stops supplying the driving current to the magnetic coil L3 by turning off the transistor TrIa, thereby turning off the contact portion 2 of the second mechanical contact switch 13. Further, the serial circuit including the resistor R5a and the transistor Tr2a may be omitted from the configuration of the hybrid relay Ic of this embodiment. If configured so, when starting to supply the power to the load 3, the transistor TrI is turned off and the transistor Tr2 is turned on as in the third embodiment. On the other hand, when cutting off the power supply to the load 3, a driving current is supplied to the magnetic coil L2 while the transistor Tr2 is being turned on, as in the third embodiment .

In accordance with the hybrid relay in each of the above-described second to fifth embodiments, when a driving current is made to flow to either of the magnetic coils Ll and L2 while flowing a driving current to the light emitting diodes LD and the magnetic coil L3, the total amount of driving current becomes large. That is, when a driving current is flown to either of the magnetic coils Ll and L2, the driving current supplied to the driving circuit of the hybrid relay temporarily becomes to peak.

In case where a control terminal apparatus communicating with a transmission control unit via power lines includes a plurality of the above-described hybrid relays and all the hybrid relays are operated to supply or cut off the power at the same timing, the peak driving current for all the relays needs to be supplied to the control terminal apparatus. To address the above, it is desirable that the supply or cutoff of powers is performed for only a part of hybrid relays, e.g., for every integer number (e.g., two) of hybrid relays, at the same timing. By performing control in this way, the peak driving current can be dispersed and an extreme voltage drop of the voltage supplied to the control terminal apparatus can be avoided.

Further, in the hybrid relays according to the above embodiments, the magnetic forces generated by the magnetic coil Ll to L3 can be attractive or repulsive forces, but may be preferably attractive forces.

(Sixth Embodiment)

A hybrid relay in accordance with a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 17 is a schematic circuit diagram showing an internal configuration of a hybrid relay in accordance with this embodiment, and FIG. 18 is a timing chart showing a state transition of each part of the hybrid relay shown in FIG. 17. Further, in the hybrid relay shown in FIG. 17, like parts to those of the configuration of the hybrid relay shown in FIG. 1 are denoted by like reference numerals, and a detailed description thereof will be omitted.

In the hybrid relay Id of this embodiment, as illustrated in FIG. 17, a second mechanical contact switch

13a, which is a latch type same as the first mechanical contact switch 12, is provided instead of the second mechanical contact switch 13 in the hybrid relay 1 (see FIG. 1) . Specifically, the second mechanical contact switch 13a includes a magnetic coil L3a which generates a magnetic force to switch the contact portion S2 to on and a magnetic coil L3b which generates a magnetic force to switch the contact portion S2 to off. These magnetic coils L3a and L3b are serially connected, and their connection node is grounded. Therefore, in this embodiment, the magnetic coils L3a and L3b are included in a second driving unit of the second mechanical contact switch 13a.

Further, the second mechanical contact switch 13a having the magnetic coils L3a and L3b is provided with diodes D6 to D9 corresponding to the diodes Dl to D4 in the first mechanical contact switch 12. Specifically, the diodes D6 and D7 whose anode electrodes are grounded are connected in parallel to the magnetic coils L3a and L3b, respectively. Moreover, cathode electrodes of the diodes D8 and D9 are connected to the cathode electrodes of the diodes D6 and D7, respectively, and anode electrodes of the diodes D8 and D9 are connected to the signal processing circuit 16d. Other components are identical to those of the hybrid relay 1 of the first embodiment, so the details thereof will be omitted.

In the hybrid relay Id, the ON/OFF switch timings of the contact portion Sl of the first mechanical contact switch 12, the contact portion S2 of the second mechanical contact switch 13a, and the triac S3 of the semiconductor switch 14 are made similar to those in the hybrid relay 1 of the first embodiment. That is, in each of the first mechanical contact switch 12 and semiconductor switch 14 having the same configuration as the hybrid relay 1 of the first embodiment, a timing at which a driving current is supplied from the signal processing circuit 16d to the magnetic coils Ll and L2 and light emitting diode LD is similar to that in the first embodiment. Therefore, the operation of the hybrid relay Id will be described below with reference to the timing chart of FIG. 18 based on the ON/OFF of the second mechanical contact switch 13a.

As illustrated in the timing chart of FIG. 18, when power is supplied to the load 3, a driving current of a pulse current is supplied to the magnetic coil L3a from the signal processing circuit 16d such that the contact portion S2 of the second mechanical contact switch 13a is turned on. When the contact portion S2 of the second mechanical contact switch 13a is switched on, the driving current is supplied to the light emitting diode LD from the signal processing circuit 16d upon lapse of time tl after supplying a driving current to the magnetic coil L3a. Accordingly, as in the hybrid relay 1 of the first embodiment, when an AC voltage from the AC power source 2 becomes a center voltage

(reference voltage) after the turn-on of the second mechanical contact switch 13a, the triac S3 is turned on in conjunction with the conduction of the phototriac S4 in the semiconductor switch 14, which results in turning on the semiconductor switch 14.

In this manner, when turning on the second mechanical contact switch 13a and the semiconductor switch 14, and the supply of power to the load 3 from the AC power source 2 is started, the signal processing circuit 16d supplies a driving current of a pulse current to the magnetic coil Ll, thereby- turning on the contact portion Sl of the first mechanical contact switch 12. When the first mechanical contact switch 12 is switched to on, the signal processing circuit 16d stops supplying the driving current to the light emitting diode LD. As a result, in the semiconductor switch 14, when the AC voltage from the AC power source 2 is a center voltage (reference voltage) , the triac S3 and the phototriac S4 become non-conductive and the semiconductor switch 14 is turned off.

In addition, upon lapse of time t2 after stopping the supply of driving current to the light emitting diode LD, the signal processing circuit 16d supplies a driving current of a pulse current to the magnetic coil L3b of the second mechanical contact switch 13a. As a result, in the second mechanical contact switch 13a, the contact portion S2 is switched off.

With this operation, the semiconductor switch 14 can be turned on during a time interval from the turning-on of the second mechanical contact switch 13a until the turning- off thereof. Further, the signal processing circuit 16d supplies a driving current to the magnetic coils L3a and L3b only when the ON/OFF of the second mechanical contact switch 13a is switched. That is, a timing for supplying a driving current to the light emitting diode LD of the semiconductor switch 14 and a timing for supplying a driving current to the magnetic coils L3a and L3b are different from each other,

Further, when the supply of power to the load 3 is cut off, the signal processing circuit 16d also supplies a driving current of a pulse current to the magnetic coils L3a and L3b only when the ON/OFF of the second mechanical contact switch 13a is switched. Specifically, a driving current is firstly supplied to the magnetic coil L3a to turn on the contact portion S2 of the second mechanical contact switch 13a, and then a driving current is supplied to the light emitting diode LD to turn on the triac S3 of the semiconductor switch 14. Thereafter, when a driving current is supplied to the magnetic coil L2 and the contact portion Sl of the first mechanical contact switch 12 is turned off, first, the supply of the driving current to the light emitting diode LD is stopped and the triac S3 of the semiconductor switch 14 is turned off. Then, a driving current is supplied to the magnetic coil L3b to turn off the contact portion S2 of the second mechanical contact switch 13a. With this embodiment, since the second mechanical contact switch 13a uses a latch type mechanical contact switch, the ON/OFF of the contact portion S2 can be switched only by supplying a driving current of a pulse current to the magnetic coils L3a and L3b. Therefore, a driving current does not flow simultaneously from the signal processing circuit 16d to the magnetic coils L3a and L3b and the light emitting diode LD. Thus, comparing to the hybrid relay 1 of the first embodiment having the normal excitation type as the second mechanical contact switch 13, the amount of driving current supplied from the signal processing circuit 16d can be reduced, thereby reducing power consumption in the hybrid relay Id.

Further, in each of the above-described embodiments, there may be configured such that the first mechanical contact switch 12 has an auxiliary contact having a small capacitance that performs opening and closing operations in conjunction with the contact portion Sl serving as a main contact, and each of the signal processing circuits 16, and 16a to 16d may check the opening and closing of the auxiliary contact to detect conduction/non-conduction of the contact portion Sl. By employing a configuration having the first mechanical contact switch 12 with this auxiliary contact, conduction/non-conduction of the contact portion Sl can be detected accurately, thereby performing shutoff operations of the contact portion S2 of the second mechanical contact switches 13 and 13a and the semiconductor switches 15 and 15a more accurately.

While the invention has been shown and described with respect to the embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.

Claims

What is claimed is:

1. A hybrid relay, comprising: a first mechanical contact switch whose contact portion is opened and closed by a first driving unit; a second mechanical contact switch whose contact portion is opened and closed by a second driving unit operating independent of the first driving unit; and a semiconductor switch serially connected to the second mechanical contact switch, wherein the first mechanical contact switch is connected in parallel to the second mechanical contact switch and the semiconductor switch which are connected serially, on a power feed path to a load from a power source, the first mechanical contact switch is a latch type mechanical contact switch, wherein a current is supplied to the first driving unit when switching between an opened and a closed state of the contact portion of the first mechanical contact switch, and each of the second mechanical contact switch and the semiconductor switch becomes conductive before opening and closing of the contact portion of the first mechanical contact switch and becomes non-conductive after opening and closing of the contact portion of the first mechanical contact switch.

2. The hybrid relay of claim 1, wherein, when each of the second mechanical contact switch and the semiconductor switch is made conductive, the semiconductor switch becomes conductive after closing the contact portion of the second mechanical contact switch, and when each of the second mechanical contact switch and the semiconductor switch is made non-conductive, the contact portion of the second mechanical contact switch is opened after making the semiconductor switch non-conductive.

3. The hybrid relay of claim 2, wherein the power source is an AC power source, and the semiconductor switch has a zero-cross firing function which is made conductive when a voltage supplied from the AC power source becomes a center voltage.

4. The hybrid relay of claim 3, wherein when each of the second mechanical contact switch and the semiconductor switch is made non-conductive, the contact portion of the second mechanical contact switch is opened upon lapse of time equal to or longer than a half period of an AC voltage from the AC power source after making the semiconductor switch non-conductive.

5. The hybrid relay of claim 1, wherein, in case of closing the contact portion of the first mechanical contact switch: the semiconductor switch is made conductive after closing the contact portion of the second mechanical contact switch; the contact portion of the first mechanical contact switch is closed, while the second mechanical contact switch and the semiconductor switch is being conductive, respectively; and substantially simultaneously, the semiconductor switch is made non-conductive and the contact portion of the second mechanical contact switch is opened, and in case of opening the contact portion of the first mechanical contact switch: substantially simultaneously, the semiconductor switch is made conductive and the contact portion of the second mechanical contact switch is closed; the contact portion of the first mechanical contact switch is opened, while the second mechanical contact switch and the semiconductor switch are being conductive, respectively; and then the contact portion of the second mechanical contact switch is opened after making the semiconductor switch non-conductive.

6. The hybrid relay of any one of claims 1 to 5, wherein the second mechanical contact switch is a normal excitation type mechanical contact switch in which a current is constantly supplied to the second driving unit while the contact portion of the second mechanical contact switch is being closed, the semiconductor switch includes a photo-coupler having a light emitting element for generating an optical signal, the photo-coupler being controlled to be conductive or non-conductive based on the optical signal of the light emitting element, and the second driving unit and the light emitting element is serially connected, and, the second driving unit and the light emitting element is driven by a common current when the second mechanical contact switch and the semiconductor switch are simultaneously made conductive.

7. The hybrid relay of claim 6, wherein, when the second mechanical contact switch and the semiconductor switch, substantially at the same time, are switched from non- conductive state to conductive state, a first current is supplied to the light emitting element and the second driving unit; and when the second mechanical contact switch and the semiconductor switch are made conductive while the second mechanical contact switch is in the conductive state, a second current smaller than the first current in magnitude is supplied to the light emitting element and the second driving unit.

8. The hybrid relay of claim 6, wherein a first current is supplied to the second driving unit when the contact portion of the second mechanical contact switch becomes closed, and, after the contact portion of the second mechanical contact switch is closed, a second current smaller than the first current in magnitude is supplied to the second driving unit.

9. The hybrid relay of any one of claims 1 to 4, wherein the second mechanical contact switch is a latch type mechanical contact switch, and a current is supplied to the second driving unit only when the opening and the closing the contact portion of the second mechanical contact switch is switched.

10. The hybrid relay of any one of claims 1 to 5, wherein a contact pressure of the second mechanical contact switch is smaller than a contact pressure of the first mechanical contact switch, and a distance between contacts in the second mechanical contact switch is smaller than a distance between contacts of the first mechanical contact switch.

11. The hybrid relay of any one of claims 1 to 5, wherein the contact portion of the first mechanical contact switch includes contacts, and a magnetic circuit in which, when the contacts are connected to flow a short-circuit current, an attractive magnetic force is formed in a direction in which the contacts of the first mechanical contact switch is closed.

12. The hybrid relay of any one of claims 1 to 5, wherein the first mechanical contact switch is further provided with an auxiliary contact operating in conjunction with the contact portion of the first mechanical contact switch, and conduction or non-conduction of the contact portion of the first mechanical contact switch is detected based on the opening and the closing of the auxiliary contact.

13. A control terminal apparatus comprising a plurality of hybrid relays as claimed in any one of claims 1 to 5, and performing the opening and the closing of the contact portions of the first mechanical contact switches for every predetermined number of hybrid relays when the opening and the closing of the contacts of the first mechanical contact switches of the hybrid relays is simultaneously switched.