JPS6024559B2 - discharge lamp lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device using a subthermal discharge lamp.

Since discharge lamps generally have negative resistance, they require a ballast to limit and stabilize the current, and in the case of commercial power sources, a stabilizing circuit using an inductance element, a capacitor, or a combination thereof is used.

When using these stabilizer circuits, the power supply voltage is 1.5 to 2. It is impossible to light up a discharge lamp without directly going through a step-up transformer using a power supply voltage comparable to the lamp voltage.For this reason, for example, AC. It was not possible to turn on the 40W crab light lamp at all with a 100V commercial power supply. For this reason, the capacitance of the inductance element becomes large, resulting in a large size, large weight, and large loss. In view of these drawbacks, the conventional circuit shown in FIG. 1 was proposed. In this circuit, the commercial power supply 1, the inductance element L of the main circuit,
A first closed circuit is formed by the discharge lamp 2, and a second closed circuit is formed by the commercial power source 1, the inductance element L, and a switch element 3 formed of, for example, a semiconductor switch element, A switch element 3 is connected to a discharge lamp 2 in parallel.

FIG. 2 shows the on/off mode of the switch element 3, and as shown in the figure, it is turned on in approximately the first half of the half cycle of the commercial power supply 1 and turned off after a certain period of time.

When current flows from the commercial power supply 1 to the switch element 3 through the inductance element L, energy is accumulated in the inductance element L, and when the switch element 3 is turned off, this energy is added to the voltage of the commercial power supply 1 and released. Apply to electric light 2. By repeating this operation, the discharge lamp 2 is always re-ignited during the lighting period, and for example, a 40W crab light lamp (lamp voltage 105V) can be directly lit at the rated power supply voltage using the ACIOOV commercial power supply 1. It becomes possible to easily light discharge lamps having similar lamp voltages. However, in the circuit shown in Figure 1, there is no consideration given to the child heat of the filament of the discharge lamp 2, so when using a child heat type discharge lamp such as a crab light lamp, a separate child heat means such as a preheating transformer is required. If the current flowing through the inductance element L is interrupted immediately before the switch element 3 is cut off, and the switch element 3 is cut off in the phase, the starting performance in low temperature conditions of the discharge lamp 2 will be poor, and the starting performance will be poor. In addition, if the ON period of the switch element 3 is made long and the switch element 3 is cut off at a point where the current flowing through the inductance element L is large, the starting performance is high, but the electrode wear increases.

Furthermore, the rate of change in the voltage across the discharge lamp 2 when the switch element 3 is shut off is large (assuming that the on period and phase are substantially fixed), and there is a possibility that noise may occur. Furthermore, if a noise prevention capacitor is inserted in parallel with the discharge lamp 2 in order to suppress the rate of change, the switch element 3 will deteriorate and noise will occur due to the rush current when the switch element 3 is turned on. In addition, since the cut-off period of the switch element 3 is constant and the thermal current is small, the starting time is long, and the energy applied to the discharge lamp 2 immediately before starting is small, so reliable starting is not possible when the ambient temperature drops, etc. There are problems such as an increase in cathode wear and a decrease in lamp luminous efficiency due to an increase in the amount of energy applied to the discharge lamp 2 during lighting. The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a discharge lamp lighting device that shortens the starting time of a preheating discharge lamp, enables reliable starting and lighting, and further reduces cathode wear. It is on offer. FIG. 3 shows a basic embodiment of the present invention, and FIG. 4 is a specific circuit diagram thereof. The commercial power supply 1, the inductance element L of the main circuit, and the discharge lamp 2 form a first leg circuit, and the commercial power supply 1, the inductance element L of the main circuit, and one filament of the discharge lamp 2 form a first leg circuit. F. For example, a transistor,
A switch element 3 such as a semiconductor having a cutoff function such as GT○, SCR, etc., and the other filament F2 of the discharge lamp 2
A second closed circuit is formed by connecting the switch element 3 between the electrodes of the discharge lamp 2 on the non-power supply side and connected in parallel to the discharge lamp 2. In this embodiment, the operation of the circuit shown in FIG.
,, A child heating current is supplied to F2, and even without a separate child heating means such as a child heating transformer, it is possible to easily start and light a child heating type discharge lamp 2 such as a crab light lamp by heating the child. can. Further, the operation of this embodiment will be explained in detail with reference to the specific circuit shown in FIG. 4 and the voltage and current waveform diagram of each part shown in FIG. The input end of a rectifier bridge 4 consisting of diodes D, D2, D3, D4 is connected between the non-power supply side electrodes of the filaments F, F2 of the discharge lamp 2, and the output end of the rectifier bridge 4 is connected A switch element 3 made of a transistor is connected, and the switch element 3 is connected in parallel to the discharge lamp 2 via a rectifier bridge 4. 5 is a control circuit for controlling the on/off operation of the switch element 3.

Thus, the switch element 3, the rectifier bridge 4, and the control circuit 5 constitute a switch section A. Now with commercial power supply 1,
When a power supply voltage as shown by the broken line in FIG. 3 is applied. On the other hand, 1 to 1 commercial power supply
The secondary winding voltage of the transformer T connected to the secondary winding is full-wave rectified by the diode bridge D5, and the base current is passed through the resistors R3 and R5 to the transistor serving as the switch element 3. Turn on the inductance element L, the filament F of the discharge lamp 2, the rectifier bridge 4,
A current flows from the commercial power supply 1 through the switch element 3, the rectifying bridge 4, and the filament F2 during the first half of approximately a half cycle, and energy is accumulated in the inductance element L. As the power supply phase advances, the resistances R, , R2, R4
When a predetermined phase determined by the relationship is reached, at time t in Fig. 5a (in other words, the ratio near the peak value of the commercial power source 1 is high, and the preheating current is increased to flow through the filaments F, , F2). Immediately after turning on, a gate current sufficient to fire the thyristor S, which is an auxiliary switching element, is applied in a period slightly shorter than half a cycle (the degree and on-period are set), and the thyristor S becomes conductive. Due to this conduction, the supply of base current to the switch element 3 is stopped, and the switch element 3 is turned off. As a result, the energy accumulated in the inductance element L is transferred in the direction of the same polarity as the voltage of the commercial power supply 1 as shown in Fig. 5a.
As shown by the solid line, a high voltage is generated across the discharge lamp 2. Therefore, the discharge lamp 2 can be lit at a sufficient rating even with a relatively low power supply voltage around the lamp voltage. Fifth
Figure b shows the current flowing through the switch element 3, Figure c shows the lamp current, and Figure d shows the waveform of the input current. A hot current and high voltage are applied to the discharge lamp not only during lighting but also when starting, so it can be started. FIG. 6 shows a circuit diagram of a second embodiment of the present invention. A series circuit with an inductance element L2 having a small value is connected between the non-power supply side electrodes of the filaments F, F2 of the discharge lamp 2.

In the case of this embodiment, the voltage across the discharge lamp 2 causes series resonance in the inductance element L and capacitor C due to the transient state when the switch element 3 is turned off, and when the discharge lamp 2 is not lit, As shown in FIG. 7a, an oscillating voltage is generated across the discharge lamp 2. By widening the inside of the high-voltage oscillating pulse in this way, the starting and re-ignition performance of the discharge lamp 2 is improved, and in particular, not only the first oscillating voltage P in FIG. th oscillating voltage P2, 3rd oscillating voltage P2,
The second oscillating voltage P3 is very effective. In addition, since the peak value of the oscillating voltage can be reduced, the peak voltage when switching elements such as transistors are cut off can be suppressed, improving reliability.
Costs can be reduced by reducing withstand voltage performance, and since the rate of change in the voltage across the discharge lamp 2 is reduced, there are effects such as noise reduction, and the inductance element L2 is connected in series with the capacitor C. Therefore, when the switch element 3 such as a transistor is turned on, the rush current to the switch element 3 due to the electric charge of the capacitor C is reduced, and there are effects such as less deterioration of the switch element 3 and noise generation. FIG. 7b shows the voltage across the discharge lamp 2 after lighting. FIG. 8 shows a third embodiment circuit of the present invention, which constitutes a series two-lamp lighting circuit. A set of filaments F2, F,' are connected in parallel, and a switch part A similar to the above is connected between the non-power supply side electrodes of the remaining filaments F, F2' of both discharge lamps 2, 2' for child heating. The transformer HT is connected through the primary winding of the transformer HT, and the secondary winding of the transformer HT is connected in parallel to the filament F2, F,', and two discharge lamps are connected at a common switch part A. 2,
2' are lit in series so that they can be manufactured at low cost.

FIG. 9 shows a circuit according to a fourth embodiment of the present invention. In this embodiment, a parallel two-lamp lighting circuit is constructed, and a commercial power source is Each filament F,, F2 of the discharge lamps 2, 2' connected in parallel to
, F,', F2' are connected between the non-power supply side poles of rectifier bridges 4, 4' such as diode bridges, and a set of switch elements 3 are discharged through these rectifier bridges 4, 4'. The switch element 3 is connected in parallel to the electric lamps 2 and 2', and the switch element 3 is connected in parallel to the discharge lamps 2 and 2', and the switch element 3 and the control circuit 5 that controls the switch element 3 are commonly used. is easy and the production cost is low.

Furthermore, in order to balance the oscillating voltage applied to each discharge lamp 2, 2', a balancing element 7, such as a capacitor, is connected between both filaments F, , F, ' of both discharge lamps 2, 2'. . FIG. 10 shows a circuit configuration of a fifth embodiment of the present invention, and FIG. 11 shows its specific circuit. In such an embodiment, a series circuit is constructed of a capacitor C between the non-power supply side electrodes of the filaments F, F2 of the discharge lamp 2, and an inductance element L2 having a smaller inductance value than the inductance element L. A switch element 3 is connected to this series circuit via a rectifier bridge 4, and the switch element 3 is a drive circuit that is operated by a signal from a phase adjustment circuit 9 that operates using a DC power supply section 8 as a power source. 10' Trowel ignition control is performed. Immediately after the voltage of the commercial power source 1 is applied to the discharge lamp circuit, the phase adjustment circuit 9 applies the voltage to the commercial power source 1 for a period slightly shorter than a half cycle of the commercial power source 1, as shown in FIG. A sufficient thermal current flows through the filaments F, F2 of the discharge lamp 2, and a current flows through the switch element 3, that is, the inductance element L.
After the current flowing through switch element 3 becomes relatively small,
As shown in Fig. 12a, a signal is output to turn off the cathode (
Filament F. , F2) to prevent wear and tear, prolong the life of the filaments JF, , F2, and heat the filaments JF, , F2 in a short period of time. FIG. 12b is a waveform diagram of the current flowing through the switch element 3 at that time, and FIG. 12c is a waveform diagram of the input current. Then, immediately before starting, the on period of the switch element 3 is made shorter than that shown in FIG. 13, for example, approximately 1/4 cycle of the commercial power supply 1, as shown in FIG. By cutting off the switch element 3 at a large phase of the current flowing through the inductance element L, as shown in Figure b, an oscillating voltage with a high peak value is applied as shown in Figure 13a. The discharge lamp 2 can be reliably started even in environments with low ambient temperature, high temperature and high humidity, etc. Furthermore, when the discharge lamp 2 has been started and is lit, the discharge lamp 2 can be started as shown in Fig. 14d. In addition, the on period of switch element 3 is further shortened,
The switch element 3 is cut off at a small phase of the current flowing through the inductance element L, as shown in figure b, and the peak value is suppressed to the minimum voltage required to keep the discharge lamp 2 lit, as shown in figure a. By shortening the current rest period of the discharge lamp 2, the lamp current during lighting can be suppressed, the wear of the electrodes of the filaments F, F2 of the discharge lamp 2 can be reduced, and the overall efficiency can be improved by increasing the light emission period. It looks like this. 13th
Figure c and Figure 14c show the waveforms of the input current. Next, the operation of this embodiment will be further explained with reference to a specific circuit shown in FIG.
That is, transformer To, diode bridge D6, resistor R8
A trapezoidal DC power supply synchronized with the commercial power supply 1 is obtained by a DC power supply section 8 consisting of a constant voltage diode, and a timer circuit comprising a resistor R9 of a relatively large resistance value of the phase adjustment circuit 9 and a capacitor C3. Immediately after the power is turned on, the voltage across the capacitor C3 is lowered to reduce the base current flowing through the transistor Tr via the resistor R9 by 4.0 cm, increasing the resistance between the emitter and collector terminals of the transistor Tr, and further increasing the resistance of the drive circuit 10. R,. through capacitor C
4, slows down the charge-up of capacitor C4, delays the conduction phase of 3-terminal thyristor Q2 through 2-terminal thyristor Q, and reduces the base current of switch element 3 through resistor R, 3. The period in which the current flows is lengthened, and the operation becomes as shown in each diagram in FIG.
<If the three-terminal thyristor Q2 is conductive, the base current of the switching element 3 made of a transistor will be cut off. >The period during which the base current flows through the switch element 3 is lengthened, resulting in an operation as shown in FIG. (Q2
If the current is suitable, the base current of the transistor Tr is cut off. ) Then, after a short period of time, when the voltage across the capacitor C3 increases and reaches 0, the base current of the transistor Tr increases, and as a result, the conduction phase of the three-terminal thyristor Q2 becomes distant, resulting in the operation shown in FIG. Become. Similarly, after a sufficient period of time has elapsed, the voltage across the capacitor C3 becomes sufficiently high, and as a result, the conduction phase of the third thyristor Q2 becomes further distant, resulting in the operation shown in FIG. 14. Furthermore, FIGS. 15, 16, and 17 show the circuit shown in FIG. 10, in which the phase adjustment circuit 9 changes the on-phase of the switch element 3, and the peak values of the preheating current and oscillating voltage are adjusted according to the 0 progress of starting. FIG. 15a is a waveform diagram of the lamp voltage immediately after the electric wire switch is turned on;
As shown in Figure c, the on phase of the switch element 3 is set to about 1/8 cycle of the commercial power supply 1 to increase the child thermal current, and the off-state current is decreased as shown in Figure b. As shown in a, the peak value of the oscillating voltage after being turned off is suppressed,
Immediately before starting, the phase is advanced to near the zero point of the power supply phase as shown in c in Fig. 16, and the current when the switch element 3 is off is changed to o in the same figure.
The starting performance is improved by increasing the oscillation voltage as shown in b and the oscillating voltage as shown in a of the same figure, and after lighting, the phase is further set to approximately -1'8 cycle as shown in c of Fig. 17. Then, as shown in Figure b, the current when the switch element 3 is off is reduced to suppress the current to the minimum necessary for restriking, and the current flowing through the discharge lamp 2 is increased to improve the luminous effect. 12, FIG. 13, and FIG. 14. Figure 17a shows the lamp voltage. In the discharge lamp lighting device configured as described above, the present invention increases the preheating current by increasing the on-period of the switch element near the peak value of the commercial power supply immediately after the commercial power supply is turned on, and also increases the preheating current immediately before the switch element is turned off. Since the instantaneous value of the heating current is set to be small, the filament of the discharge lamp can be sufficiently heated even without a heating means, and therefore the starting performance of the discharge lamp is improved even when the temperature is low. Furthermore, when starting a discharge lamp, the on-period of the switch element is centered around the first half of the commercial power supply's half cycle to reduce the preheating current, and the instantaneous value of the child heating current immediately before turning off is increased. Since it is set near the peak value of the thermal current, a large starting pulse can be generated when the switch element is turned off, ensuring reliable starting and lighting.Furthermore, while the discharge lamp is lit, the switch element remains on. The period is centered around the beginning of the half cycle of the commercial power supply, and is set around the first half of the half cycle of the commercial power supply so that the instantaneous value of the child heating current decreases and the instantaneous value of the preheating current just before turning off also decreases by 4. Since it is set to , the energy applied to the discharge lamp during lighting does not become large, which has the effect of reducing wear and tear on the filament (cathode).

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of the first embodiment of the present invention, FIG. 2 is an explanatory diagram of the same operation as above, FIG. 3 is a circuit diagram of the second embodiment of the present invention, and FIG. 4 is the same as above. Specific circuit diagram, Figure 5 a to d
6 is a circuit configuration diagram of the third embodiment of the present invention, FIGS. 7a and b are waveform diagrams for explaining the same operation, and FIG. 8 is a waveform diagram of each part for explaining the operation of the same as above. FIG. 9 is a circuit diagram of the fourth embodiment of the invention; FIG. 9 is a circuit diagram of the fifth embodiment of the invention;
FIG. 10 is a circuit configuration diagram of the sixth embodiment of the present invention, and FIG.
The figures are specific circuit diagrams of the same as above, Figures 12 a to d, and Figures 13 a to
d, FIGS. 14 a to d are waveform diagrams of each part for explaining the same operation as above, FIGS. 15 a to c, FIGS. 16 a to c, and FIGS. 17 a to d.
c is a waveform diagram of each part for explaining the operation of another usage example of the circuit in FIG. is an inductance element, and C is a capacitor. Figure l Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure - Figure! Figure 2 - Figure 3 Younger brother - Figure 4 - Figure 5! Figure 6 - Figure 7

Claims (1)

[Scope of Claims] 1 A first closed circuit is formed by a commercial power source, an inductance element constituting the main circuit, and a preheating discharge lamp, and a first closed circuit is formed between the non-power supply side poles of the preheating discharge lamp in parallel. A switch element is connected and turned on for a period of time during each half-cycle of said utility power to store energy in an inductance element during this on-period and then to the next switch element off-period during each half-cycle of said utility power. In a discharge lamp lighting device that superimposes the stored energy on the commercial power supply and applies it to the discharge lamp to start and light the lamp, the on-period of the switch element described above is increased so that the ratio near the peak value of the commercial power supply is increased immediately after the commercial power supply is turned on. By doing so, the preheating current is increased and the instantaneous value of the preheating current immediately before turning off is set to be small, and when starting the discharge lamp, the on period of the switch element is set around the first half of the half cycle of the commercial power supply, and the preheating current is set to be small. At the same time, the instantaneous value of the preheating current immediately before turning off is set near the peak value of the preheating current so that it becomes large, and the on period of the switch element is set near the beginning of the half cycle of the commercial power supply while the discharge lamp is lit. Discharge lamp lighting characterized by comprising control means for setting the temperature near the first half of a half cycle of the commercial power supply so that the instantaneous value of the preheating current is reduced and the instantaneous value of the preheating current immediately before turning off is also small. Device. 2. Control means for controlling the on-period of the switch element to be a little shorter than half a cycle immediately after turning on the commercial power, to approximately one-quarter cycle when the discharge lamp is started, and to be even shorter while the discharge lamp is on. A discharge lamp lighting device according to claim 1, characterized in that the discharge lamp lighting device is provided with: 3. The on-period of the switch element is set to a constant value of approximately half a cycle of the commercial power supply, and the on-start phase is approximately approximately one-eighth cycle immediately after turning on the commercial power supply, and approximately approximately the zero point of the power supply phase at the time of startup; And when the light is on, it is approximately minus 8
2. The discharge lamp lighting device according to claim 1, further comprising a control means for controlling the discharge lamp to approximately 1/1 cycle.