JPH05327454A - Heat-sensitive switch - Google Patents

Abstract

PURPOSE:To secure the connection between a heat-sensitive switch and a load and an AC power supply respectively in a 2-wire system. CONSTITUTION:A contact r1 of a relay Ry1 is connected to both ends of a series circuit of an AC power supply AC and a load L, and the ON/OFF states of the load L are controlled by the open/close states of the contact r1. The drive of the relay Ry1 is controlled by a drive circuit 2 in accordance with the output of a sensor circuit 1 which senses the heat rays. A 1st power circuit 3 produces the power supply of each part from the current flowing via the contact r1 when this contact is closed. A 2nd power circuit 4 also produces the power supply of each part from the both-end voltage of the contact r1 when this contact is opened. Thus, both circuits 3 and 4 can supply the power to the internal circuits regardless of the open/close states of the contact r1 and even the connection is secured to the load L and the power supply AC in a 2-wire system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal switch which senses heat generated by a human body and controls the operation of a load.

[0002]

2. Description of the Related Art In this type of heat sensitive switch, the load is turned on and off by controlling the supply and stop of power to the load by turning on and off the switch means. Here, a relay contact or a triac is used as the switch means.

[0003]

By the way, in this kind of thermal switch, it is necessary to always operate the internal circuit regardless of whether the load is on or off. Here, when the two-wire type wiring connecting the hot feeling switch to the AC power source through the load,
Since power cannot be supplied to the internal circuit when the switch means is turned on or off, the power supply for the internal circuit has conventionally been taken by another path. Therefore, there has been a problem that 3-wire or 4-wire wiring is required.

The present invention has been made in view of the above points, and an object of the present invention is to provide a thermal switch which can be wired in a two-wire system.

[0005]

According to the present invention, in order to achieve the above object, a switch means connected to both ends of a series circuit of an AC power source and a load for controlling ON / OFF of the load,
A sensor circuit that senses heat rays, a drive circuit that controls ON / OFF of the switch means according to the output of the sensor circuit, and a power supply for each of the above parts are generated from the current that flows through the switch means when the switch means is closed. And a second power supply circuit that creates a power supply for each of the above parts from the voltage across the switch means when the switch means is opened.

[0006] From the viewpoint of withstand capacity or cost,
It is preferable to use a relay contact as the switch means.

[0007]

The present invention has the above-mentioned configuration,
Even if the thermal switch is connected to the AC power supply and the load by the two-wire wiring, the first and second power supply circuits can supply power to the internal circuit regardless of opening and closing of the switch means.

[0008]

1 and 2 show an embodiment of the present invention. As shown in FIG. 1, the thermal switch of the present embodiment has contacts r ₁ connected to both ends of a series circuit of an AC power supply AC and a load L, and controls on / off of the load L by opening / closing the contact r _1. a relay Ry _1, a sensor circuit 1 for sensing heat rays, and a drive circuit 2 for controlling the driving of the relay Ry ₁ in accordance with the output of the sensor circuit 1, via the contact r ₁ upon closing of the contacts r ₁ It is provided with a first power supply circuit 3 which creates a power supply for each of the above parts from the flowing current, and a second power supply circuit 4 which creates a power supply for each of the parts based on the voltage across the contact r ₁ when the contact r ₁ is opened.

As the relay Ry _1, as shown in FIG. 2, a latching relay is used.
_In order to open / close the contact r ₁ at ₁ , it is necessary to pass a pulse current through the coil for opening / closing the contact r ₁ . Therefore,
In this embodiment, a pulse generating circuit 5 for generating a pulse signal having a constant pulse width when the output of the sensor circuit 1 changes is provided, and the output of the pulse generating circuit 5 is connected in series to the coils for opening and closing the contacts. The transistors Q ₂ and Q ₃ of the drive circuit 2 are turned on.

The first power supply circuit 3 includes a current transformer CT ₁ having a primary winding inserted in a loop in which power is supplied from an AC power supply AC to a load L via a contact r ₁ , and the current transformer CT ₁ The secondary voltage rectification circuit is composed of diodes D ₁ and D ₂ and capacitors C ₁ and C ₃ for rectifying and smoothing the secondary output. The current transformer C
A limit circuit composed of Zener diodes ZD ₁ and ZD ₂ for limiting the input voltage to the voltage doubler rectifier circuit is provided at both ends of the secondary winding of T ₁ .

The second power supply circuit 4 rectifies and smoothes the voltage of the AC power supply AC input via the load L to create a power supply, and the capacitor C of the first power supply circuit 3 is used for smoothing.
₂ and C ₃ are also used. Further, a DC cut capacitor C ₁ is provided on the input side of the rectifying / smoothing unit, and a resistor R ₁ and a Zener diode Z for controlling the input voltage to be constant.
A voltage limiting circuit consisting of D ₃ is provided.

In the case of the present embodiment, each of the above power supply circuits
Output of diode D_FourAnd capacitor C_FiveAdjusted
The smoothed voltage is supplied to the drive circuit 2.
In order to ensure the operation of the sensor circuit 1,
The voltage supplied from the source circuits 3 and 4 is the transistor Q.₁,
Zener diode ZD_Five, Capacitor C₆And resistance R ₂
Sensor circuit by converting it to a constant voltage using the constant voltage circuit 6
1 is being supplied.

By the way, when using this kind of heat sensitive switch, it is preferable that the operation of the load L can be turned on and off manually, so that the heat sensitive switch is provided with a switch SW ₁ which is manually operated. . This switch SW ₁ applies the output voltage of the constant voltage circuit 6 to the high level by applying it to the output line of the sensor circuit 1 at the time of on operation, and turns on the transistor Q ₄ at the low level of the output line at the time of off operation. There is. The load L is automatically turned on and off by the output of the sensor circuit 1 at the time of switching to the intermediate position. Further, the sensor circuit 1 is
The sensor unit 1a and variable resistors VR ₁ and VR ₂ for setting sensitivity and operation of the sensor unit 1a.
And CdS7.

The operation of this heat sensitive switch will be described below.
It When the sensor circuit 1 detects a heat ray emitted to the human body,
The output goes to high level, and a pulse signal with a constant pulse is output.
It is output from the loose generation circuit 5 and the transistor Q₂Is on
Next, relay Ry₁Contact point r ₁Closes. By this
AC power is supplied to the load L and the load L turns on.
Become. For example, if the load L is a luminaire,
Lights up.

Here, until the contact point r ₁ is closed as described above, each part is operated by the electric power supplied from the second power supply circuit 4. Then, when the contact r ₁ is closed, power is supplied from the first power supply circuit 3 to each part. After that, when the heat ray from the human body is no longer detected, the output of the sensor circuit 1 becomes low level at this time, and at this time, the transistor Q ₃ is turned on by the output of the pulse generation circuit 5, and the contact r _{1 of the} relay Ry ₁ is turned on. Is opened. As a result, the operation of the load L is stopped. After that, power is supplied from the second power supply circuit 4 to each unit.

As described above, in this embodiment, since the first and second power supply circuits 3 and 4 are provided, it is not necessary to take the power supply for the internal circuit through another route, and the AC power supply AC and the load are connected by the two-wire wiring. It can be connected to L. Moreover, the two-wire wiring has an advantage that it can be easily replaced with a normal switch such as a conventional one-way switch. Also, relay R
Since the contact is switched using the contact r _{1 of} y ₁ , it is less likely to be limited in capacity as in the case of a triac, and is suitable for controlling a lighting fixture including a fluorescent lamp. Will be things.

[0017]

As described above, according to the present invention, switch means connected to both ends of a series circuit of an AC power source and a load for controlling ON / OFF of the load, a sensor circuit for detecting a heat ray, and a sensor circuit of this sensor circuit. A drive circuit for performing on / off control of the switch means in accordance with the output, a first power supply circuit for generating a power source for the respective parts from the current flowing through the switch means when the switch means is closed, and the opening of the switch means. At times, a power supply for each of the above parts is created from the voltage across the switch means.
Since the first and second power supply circuits can be used to supply power to the internal circuit regardless of whether the switching means is opened or closed, the thermal switch can be connected to an AC power supply and a load by two-wire wiring. Can be connected.

If a relay contact is used as the switch means, it is effective in terms of withstand capacity or cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the present invention.

FIG. 2 is a specific circuit diagram of the above.

[Explanation of symbols]

1 sensor circuit 2 drive circuit 3 first power supply circuit 4 second power supply circuit r ₁ contact AC AC power supply L load

Claims (2)

[Claims] 1. A switch circuit connected to both ends of a series circuit of an AC power source and a load for controlling ON / OFF of the load, a sensor circuit for detecting a heat ray, and a switch circuit for turning on according to the output of the sensor circuit. ， With a drive circuit that performs off control,
A first power supply circuit that creates the power supply for each of the above parts from the current that flows through the switch means when the switch means is closed, and a second power supply circuit that creates the power supply for the above parts from the voltage across the switch means when the switch means is open. A thermal switch comprising a power circuit. 2. The thermal switch according to claim 1, wherein a relay contact is used as the switch means.