JPS6110896A - discharge lamp lighting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to lighting a discharge lamp using a device consisting of a semiconductor chip element and a nonlinear capacitor as a starting device for a discharge lamp equipped with a preheating electrode such as a fluorescent lamp. Concerning improvements to equipment.

[Prior art]

An example of a conventional fluorescent lamp lighting device using a semiconductor switch element and a nonlinear capacitor is shown in FIG.

This connects a discharge lamp 2 to an AC power source via a ballast 1, and connects a nonlinear capacitor 4, diodes 5 and 2 in parallel with the discharge lamp 2 on the non-power side of the preheating electrodes 3a and 3b of the discharge lamp 2. It is connected to a preheating circuit consisting of a series circuit of terminal silicon symmetrical switches (hereinafter referred to as SSS) 6. In this circuit, power supply terminal U-
When an AC voltage eUv (voltage waveform is shown by a dotted line in FIG. 3) is applied between V and V, initially, 5ss6 is turned on at an appropriate phase θ1 of the positive half cycle of the power supply, and the ballast 1 and preheating electrode 3a , the diode 5, the sss 6, and the preheating electrode 3b, and the preheating electrodes 3a and 3b are heated. After the preheating current flows, the preheating current becomes zero at a phase θ2 of the negative half of the power supply voltage, and the sss 6 turns off. At this time, since the voltage of the wandering linear capacitor 4 is zero and the power supply voltage eUv is near the negative peak value, the nonlinear capacitor 4 is charged via the ballast 1 to the illustrated polarity. On the other hand, the relationship between the charge of the nonlinear capacitor 4 and the voltage E is the fourth
As shown in the figure, it has hysteresis characteristics. Therefore, if the coercive voltage is set a little lower than the peak value of the AC voltage, the charging current will decrease rapidly near the peak value of the power supply voltage. ,Ld
A high voltage pulse equivalent to I/dt is generated. Thereafter, as the above operations are repeated, the preheating electrodes 3a and 3b of the discharge lamp 2 are heated, and finally discharge is started due to the high voltage pulse.

When discharge starts, the lamp voltage drops below the turn-on voltage of 888 $, and 5ss6 does not turn on and stable discharge is maintained.

Through the above operations, the preheating electrodes 3a and 3b of the discharge lamp 2
Discharge is started by heating the electrode and applying a high-voltage pulse, but in the circuit shown in Figure 2, the high-voltage pulse is applied between the preheated electrodes 3a and 3b, which have not yet been sufficiently heated, almost at the same time as the switch is turned on. This resulted in severe consumption of the material, significantly shortening the life of the discharge lamp.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and is a discharge lamp equipped with a preheating electrode and a high-voltage pulse generation circuit made of a nonlinear capacitor connected in parallel, in which the preheating electrode is sufficiently heated. This problem is attempted to be solved by applying a high-voltage pulse afterwards.

[Structure and operation of the invention]

FIG. 1 shows an embodiment of a discharge lamp lighting device according to the present invention. In the figure, 1 is a discharge lamp such as a fluorescent lamp, 2m and 2b are preheating electrodes, 3 is a ballast, and U4 is an AC power terminal. A preheating circuit consisting of a series circuit of a diode 4 and a first semiconductor switch element such as 8885 is connected to the non-power side of the preheating electrodes 2a and 2b of the discharge lamp 1. Further, connected in parallel with the preheating circuit is a high voltage pulse generating circuit comprising a series circuit of a nonlinear capacitor 6 and a second semiconductor switching element, such as a triac T.

8 is a constant voltage trigger element connected to the gate of the triac T, 9 is an electrolytic capacitor connected to the constant voltage trigger element, a charging resistor of a 1000 electrolytic capacitor, 11 and 1
2 are discharge resistances of the electrolytic capacitor 9 and the nonlinear capacitor 6, respectively. Next, the operation of this circuit will be explained. When an AC voltage e is applied between the power supply terminals U-4, the preheating electrodes 2a and 2b of the discharge lamp 1 are heated by the operation of the preheating circuit. At the same time, a current limited by resistor 10 flows through electrolytic capacitor 9, resistor 10 and diode 4 of the charging circuit, and electrolytic capacitor 9 is gradually charged until sss 5 is turned on in the positive half cycle of the AC power supply. After a certain period of time, when the voltage across the electrolytic capacitor 9 becomes equal to or higher than the turn-on voltage of the constant voltage trigger element 8, a pulse current flows through the electrolytic capacitor 9 into the gate of the triac 7, turning the triac T on. During this time, the preheating current in the preheating circuit becomes zero and the 5885 turns off. At this time, since the voltage of the nonlinear capacitor 6 is zero and the AC power supply voltage is near the negative peak value, charging current flows into the nonlinear capacitor 6, and when it decreases rapidly, LdV is generated in the inductive ballast 3. Considerable high-voltage pulses are generated. The width of the pulse current flowing through the gate of the triac 7 is determined by the time constants of the electrolytic capacitor 9 and the resistors 11 and 12. The resistor 12 is for preventing the rapid discharge current of the nonlinear capacitor 6 from flowing into the discharge lamp.

When the high-voltage pulse is generated in this way, the preheating electrodes 2a and 2b of the discharge lamp 1 have already been sufficiently heated, so the discharge lamp 1 immediately starts discharging.

Furthermore, even if the discharge lamp 1 cannot start discharging due to the first high-voltage pulse, the above operation is repeated, so the second. The third high-voltage pulse ensures that the discharge lamp 1 starts discharging.

Figures 5 (,) to (d) are current and voltage waveforms at each part of the circuit shown in Figure 1, Figure 5 (-) is the AC power supply voltage, and Figure 5 (b) is the preheating electrode of the discharge lamp 1. Voltage between 2a and 2b,
FIG. 5(C) is a waveform diagram showing the charging/discharging current of the electrolytic capacitor 9, and FIG. 5(d) is a waveform chart showing the voltage across the electrolytic capacitor 9. FIGS. 6 and 7 show other embodiments of the present invention. The circuit in Figure 6 is the triac 7 of the circuit in Figure 1.
It is advisable to use 8CRγ' instead of 8CR. The hysteresis loop shown in Figure 2 collapses and the nonlinear capacitor's characteristics are lost, so the generated pulse becomes extremely small. Therefore, by connecting it like the resistor 13, it becomes possible to maintain the hysteresis looseness of the nonlinear capacitor 6 and easily light the discharge lamp.

The difference between the circuit in Figure 7 and the circuit in Figure 1 is the resistance 14.1.
The point is that the voltage divided by 5 charges the myolysis capacitor 9. This circuit uses a resistor 1 when preheating the discharge lamp 1.
4 is set to be higher than the breakover voltage of the constant voltage trigger element 8, and when the lamp voltage decreases after lighting the discharge lamp 10, the voltage applied across the resistor 14 is set to the breakover voltage of the constant voltage trigger element 8. By setting the voltage below the overvoltage, the triac 7 of the high-voltage pulse generation circuit will not turn on after the discharge lamp 1 is turned on, so the inflection point (system voltage) indicating the nonlinear characteristics of the nonlinear capacitor 6 will be lower than the lamp voltage. It has the advantage of being able to use

〔Effect of the invention〕

As is clear from the above description, in the present invention, a semiconductor switching element is connected in series with the nonlinear capacitor of the high-voltage pulse generation circuit, and after the power is turned on, the semiconductor switching element is turned on and off at regular intervals of M to preheat the discharge lamp. Since the high voltage pulse is generated after the electrode has been sufficiently heated, the so-called cold cathode discharge phenomenon during the period of insufficient heating of the preheated electrode can be prevented and the life of the discharge lamp can be improved.

Furthermore, since the number of times the nonlinear capacitor is charged and discharged can be appropriately suppressed, there is also the advantage that the life span of the nonlinear capacitor itself can be improved.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a discharge lamp lighting device according to the present invention, Fig. 2 is a circuit diagram of a conventional discharge lamp lighting device, Fig. 3 is a waveform diagram of a high voltage pulse in the same device, and Fig. 4 is a diagram of a nonlinear capacitor. A charge-voltage characteristic diagram, FIG. 5 is a voltage/current waveform diagram of each part of the circuit in FIG. 1, and FIGS. 6 and 7 are circuit diagrams of other embodiments of the discharge lamp lighting device according to the present invention. . In FIG. 1, 1...discharge lamp, 2a, 2b...preheating electrodes, 3...ballast, 4...diode, 5...
1st semiconductor switch element, 6... nonlinear capacitor, 1... 2nd semiconductor switch element. Figure 1 Figure 2 Figure 3 Figure 6 Figure 7

Claims (1)

[Claims] A discharge lamp comprising a preheating electrode connected to an AC power source via an inductive ballast, and a first semiconductor switch element connected in parallel with the discharge lamp on the non-power side of the preheating electrode of the discharge lamp. A preheating circuit for the preheating electrode consisting of a series circuit of diodes, a high voltage pulse generation path consisting of a series circuit of a second semiconductor switching element and a nonlinear capacitor, and a gate that connects the second semiconductor switching element of the high voltage pulse generation circuit. Consists of a gate circuit that generates a signal,
After the AC power is turned on and until the discharge lamp starts, the gate circuit causes the second semiconductor switching element of the high-voltage pulse generation circuit to be alternately rendered non-conductive and conductive at regular intervals, While the semiconductor switch is in a non-conductive state, the preheating circuit sufficiently heats the preheating electrode of the discharge lamp, and at the same time as the second semiconductor switch element becomes conductive, a charging current is caused to flow through the nonlinear capacitor to generate a high voltage pulse. A discharge lamp lighting device configured as follows.