JPS5825600Y2 - Discharge lamp delay extinguishing device - Google Patents

Description

[Detailed Description of the Invention] In the present invention, a discharge lamp 5 is connected to a commercial power source E via a power switch 1 and a commercial ballast 4, and a starting switch 6 is connected in parallel to the discharge lamp 5. 1, a series circuit of a bidirectional thyristor 2 and a heat generating resistor 7 is connected in parallel to the bidirectional thyristor 2, a resistor 8 is connected in parallel to the bidirectional thyristor 2, and a negative characteristic thermistor 3 is thermally coupled to the heat generating resistor 7. A discharge lamp delay extinguishing device is constructed by connecting a series circuit with a series circuit and connecting a dividing point of the series circuit to the gate of the bidirectional thyristor 2, and its purpose is to have a long life and a simple configuration. An object of the present invention is to provide a discharge lamp delay extinguishing device that can be manufactured.

In the conventional discharge lamp delayed extinguishing device, as shown in FIG. 2, a heat generating resistor 7 and a bimetal switch 2' are connected in parallel to a power switch 1, respectively.

In the figure, 4 is a commercial ballast, 6 is a push-button type self-resetting start switch, and 5 is a discharge lamp.

By the way, in such a conventional device, after the power switch 1 is opened, the bimetal switch 2' is turned on to the discharge lamp 5 within a certain elapsed time.
However, since the bimetal switch is used, the life of the contacts is short, and the structure is complicated.

The present invention has been proposed in view of the above-mentioned drawbacks, and will be explained below with reference to Examples.

FIG. 1 shows an embodiment of the circuit, and elements having the same numbers as those in the circuit of FIG. 2 have the same structure and function.

In the figure, reference numeral 2 denotes a bidirectional silicon risk, which is connected in parallel to the power switch 1 via a heat generating resistor 7.

This bidirectional thyristor 2 has a resistor 8 connected in parallel, and a negative characteristic thermistor 3 which is thermally coupled to the heat generating resistor 7.
A series circuit is connected between the resistor 8 and the negative characteristic thermistor 3, and the dividing connection point between the resistor 8 and the negative characteristic thermistor 3 is connected to the gate of the bidirectional thyristor 2.

Now, when the power switch 1 is opened while the discharge lamp 5 is lit, the bidirectional thyristor 2 is turned on and conductive by the gate current flowing through the resistor 8, and the discharge lamp current flows through the bidirectional thyristor 2. The light flows to the discharge lamp 5 and maintains the lighting state of the discharge lamp 5.

At this time, the heat generating resistor 7 generates heat due to the discharge lamp current, heats the thermally coupled negative characteristic thermistor 3, and reduces the resistance value of the negative characteristic thermistor 3.

Therefore, the gate current decreases below the gate firing limit current of the bidirectional thyristor 2, and eventually the bidirectional thyristor 2
becomes non-conductive, cutting off the discharge lamp current of the discharge lamp 5,
Turn off the discharge lamp 5.

Once the discharge lamp 5 is turned off, the discharge lamp 5 will not be turned on unless the start switch 6 is pressed. Therefore, after the discharge lamp 5 is turned off, the negative characteristic thermistor 3 cools down, and even if the resistance value increases, the bidirectional thyristor 2 is not conductive and connects when the light is off.

Note that the time timing when the bidirectional thyristor 2 is switched to non-conduction is set by the resistor 8 and the negative characteristic thermistor 3.

The present invention is configured as described above and uses a semiconductor switch consisting of a bidirectional thyristor, etc., so there is no need for a conventional bimetallic switch, resulting in a long life, greatly improved performance, and a simple configuration. Furthermore, since bidirectional thyristors are not energized when turned on, there is no need to create a space for heat dissipation or a heat dissipation structure, and the combination of a negative characteristic thermistor and a heat generating resistor eliminates indirect heat generation. Since it is a type, there is no need to increase the size of the device structure in order to particularly improve element reliability, and therefore it is advantageous in terms of space and cost compared to a directly heated type structure using a positive temperature coefficient thermistor.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a circuit diagram of a conventional example, 1 is a power switch, 2 is a bidirectional thyristor,
3 is a negative characteristic thermistor, 4 is a commercial ballast, 5 is a discharge lamp,
6 is a starting switch, 7 is a heat generating resistor, 8 is a resistor, and E is a commercial power source.

Claims (1)

[Scope of utility model registration request] A discharge lamp is connected to a commercial power source via a power switch and a commercial ballast, an electromotive switch is connected in parallel to the discharge lamp, and a series circuit of a bidirectional cyrisk and a heat generating resistor is connected in parallel to the power switch. A series circuit consisting of a resistor and a negative characteristic thermistor that is thermally coupled to the heating resistor is connected in parallel to the bidirectional thyristor, and the dividing point of this series circuit is connected to the gate of the bidirectional thyristor. Discharge lamp delay extinguishing device consisting of connected devices.