JPH0590895U - Discharge lamp starter - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the starting performance by increasing the pulse voltage at the start. [Structure] A capacitor C ₂ is connected between the gate and cathode of the semiconductor switch 4. During the high voltage by the capacitor C ₂ is also applied, to be charged in the capacitor C _2,
No current flows through the gate of the semiconductor switch 4 and the semiconductor switch 4 is turned on with a delay. Therefore, the startability can be improved by eliminating the absorption of the pulse voltage in the semiconductor switch 4 and generating a high pulse voltage.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a discharge lamp starting device for starting and lighting a discharge lamp such as a fluorescent lamp.

[0002]

[Prior Art]

 FIG. 3 shows a conventional example of this type of discharge lamp starting device, in which a power source side terminal of a filament of a lamp 3 (for example, a discharge lamp made of a fluorescent lamp) is connected to an AC power source 1 via a ballast 2. There is. The diode D is connected to the non-power supply side terminal of the filter of the lamp 3. ₁ And capacitor C₁And a series circuit of the semiconductor switch 4 is connected. An SSS (bidirectional two-terminal thyristor) is used as the semiconductor switch 4.

The operation of this circuit at the time of starting the lamp 3 is as follows. That is, when a voltage is applied to the diode D ₁ in the forward direction when the power is turned on, the semiconductor switch 4 is in the ON state, and a preheating current flows through the semiconductor switch 4 to the filament of the lamp 3. When the charging current to the capacitor C ₁ becomes less than the holding current of the semiconductor switch 4 in the next half cycle, the semiconductor switch 4 is turned off, and this turn-off causes the ballast 2 to generate a kick voltage (pulse voltage) in the same direction as the power supply voltage. Occurs. By repeating this, the lamp 3 is started.

FIG. 4 shows another conventional example, in which a thyristor is used as the semiconductor switch 4 instead of the SSS, and a Zener diode ZD ₁ , resistors R ₁ , R _{2 and the} like have a voltage discrimination function and a diode D ₂ This is an example in which a diode bridge is assembled by ~ D ₅ to make it bidirectional so that the same operation as the above SSS is performed. Now, the case of the forward half cycle of the diode D _1, is a voltage applied to the Zener diode ZD ₁ and through the diodes D _1, D _2, the Zener diode ZD ₁ is turned on, the semiconductor switch 4 consisting of a thyristor Turn on. When the semiconductor switch 4 is turned on, a preheating current is passed to preheat the filament of the lamp 3.

In the next half cycle, a voltage is applied to the Zener diode ZD ₁ via the diode D ₃ , the Zener diode ZD ₁ is turned on, and the semiconductor switch 4 composed of a thyristor is turned on. Then, when the charging current of the capacitor C ₁ becomes less than the holding current of the semiconductor switch 4, the semiconductor switch 4 is turned off, and by this turning off, a pulse voltage is generated in the ballast 2 in the same direction as the power supply voltage. By repeating this, the lamp 3 is started.

[0006]

[Problems to be solved by the device]

In such a conventional example, the generation of the pulse voltage for turning on the lamp 3 at the time of starting is as shown in FIG. 5, in the portion A in which the voltage charged in the capacitor C ₁ and the power supply voltage are superposed, and the capacitor When the charging current to C ₁ becomes less than the holding current of the semiconductor switch 4 and the current is cut off, it becomes a combination of the part B generated from the ballast 2.

Note that FIG. 5A shows the voltage across both ends of the starter including a circuit provided on the non-power supply side of the lamp 3, and FIG. 5B shows the waveform of the current flowing through the starter. Here, in order to secure the startability at low temperature and high temperature, a pulse voltage of a certain value or more is required, but the above-mentioned portion A is about twice the power supply voltage (when the power supply voltage is AC 100 V, 220 to 230 V), and even in the portion B, when the charging current of the capacitor C ₁ is cut off and a high pulse voltage is generated, the applied voltage value at which the semiconductor switch 4 is turned on (when the power supply voltage is applied as the starting operation). Since the semiconductor switch 4 needs to be turned on, if the voltage becomes 100 to 120 V or higher), the semiconductor switch 4 is turned on again and absorbs the pulse voltage, so that a high voltage is generated. It was difficult. Therefore, there is a problem that the startability at low temperature and high temperature cannot be satisfied.

The present invention has been made in view of the above points, and provides a discharge lamp starting device capable of increasing the pulse voltage at the time of starting and improving the starting performance. Is.

[0009]

[Means for Solving the Problems]

 The present invention connects the power supply side terminal of the filament of the discharge lamp to the AC power supply via a ballast, and connects the parallel circuit of the diode and the capacitor at both ends of the non-power side terminal of the filament of the discharge lamp. Connected to a series circuit with a semiconductor switch that turns on when a voltage above a certain voltage is applied to the semiconductor switch, and the charging current to the above capacitor falls below the holding current of the semiconductor switch and the semiconductor switch turns off. A discharge lamp starting device for starting and lighting a discharge lamp with a pulse voltage to provide a delay means for delaying and turning on the semiconductor switch when a voltage higher than a certain voltage is applied to the semiconductor switch. Is.

[0010]

[Action]

 Thus, when a high voltage is applied to the semiconductor switch, the semiconductor switch is delayed and turned on, so that the absorption of the pulse voltage in the semiconductor switch is eliminated and a high pulse voltage can be generated, and the starting performance is improved. Can be improved.

[0011]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. The present invention eliminates absorption of the pulse voltage in the semiconductor switch and generates a high pulse voltage by turning on the semiconductor switch with a delay when a high voltage is applied to the semiconductor switch. , To improve the startability.

FIG. 1 shows a specific circuit. FIG. 1 shows an embodiment corresponding to FIG. 4 of the prior art, in which a capacitor C ₂ is connected between the gate and cathode of a semiconductor switch 4 composed of a thyristor. Also high voltage by the capacitor C ₂ is applied, while Ru is charged in the capacitor C _2, without flowing current to the gate of the semiconductor switch 4, is charged on Ne以with capacitor C _2, the semiconductor switch 4 Turns on. That is, even if a high voltage is applied, the semiconductor switch 4 will be turned on with a delay. Therefore, the startability can be improved by eliminating the absorption of the pulse voltage in the semiconductor switch 4 and generating a high pulse voltage.

Here, the capacitor C ₂ constitutes a delay means for delaying and turning on the semiconductor switch 4 when a voltage higher than a certain voltage is applied to the semiconductor switch 4. Also, since the entire operation is the same as the conventional example, the description is omitted. (Embodiment 2) FIG. 2 shows Embodiment 2 in which a transistor Tr ₁ which is a member constituting a voltage discriminating function is provided, a Zener diode ZD ₁ is connected to the base of the transistor Tr ₁ , and a delay is provided in parallel with a resistor R _2. The capacitor C ₂ constituting the means is connected. This capacitor C ₂ can delay the zener diode ZD ₁ being turned on, that is, the semiconductor switch 4 being turned on as in the previous embodiment.

The present invention can also be applied to the case where SSS is used as the semiconductor switch.

[0015]

[Effect of the device]

 As described above, the present invention connects the power source side terminal of the filament of the discharge lamp to the AC power source via a ballast, and connects the diode and the capacitor in parallel at both ends of the non-power side terminal of the filament of the discharge lamp. Connect a series circuit with a circuit and a semiconductor switch that turns on when a voltage above a certain voltage is applied bidirectionally, and when the charging current to the above capacitor is less than the holding current of the semiconductor switch and the semiconductor switch turns off. In a discharge lamp starting device for starting and lighting a discharge lamp by a generated pulse voltage, a delay means for delaying and turning on the semiconductor switch when a voltage higher than a certain voltage is applied to the semiconductor switch is provided. Therefore, when a high voltage is applied to the semiconductor switch, the semiconductor switch is delayed and turned on. Eliminating absorption, it is possible to generate a high pulse voltage, in which an effect capable of improving the starting performance.

[Brief description of drawings]

FIG. 1 is a detailed circuit diagram of an embodiment of the present invention.

FIG. 2 is a circuit diagram of a main part of a second embodiment of the above.

FIG. 3 is a circuit diagram of a conventional example.

FIG. 4 is a circuit diagram of another conventional example.

FIG. 5 is an operation waveform diagram in the starter.

[Explanation of symbols]

1 AC power supply 2 Ballast 3 Lamp 4 Semiconductor switch C ₂ Capacitor

Claims (1)

[Scope of utility model registration request] 1. A power supply side terminal of a filament of a discharge lamp is connected to an AC power source through a ballast, and a parallel circuit of a diode and a capacitor is bidirectionally provided at both ends of a non-power side terminal of the filament of the discharge lamp. Connect a series circuit with a semiconductor switch that turns on when a voltage above a certain voltage is applied,
In a discharge lamp starting device for starting and lighting a discharge lamp with a pulse voltage generated when the charging current to the capacitor is less than the holding current of the semiconductor switch and the semiconductor switch is turned off, a constant voltage is applied to the semiconductor switch. A discharge lamp starting device comprising delay means for delaying and turning on the semiconductor switch when the above voltage is applied.