JPS6052560B2 - discharge lamp lighting device - Google Patents

Description

[Detailed Description of the Invention] The present invention is suitable for lighting three discharge lamps by rectifying an AC power supply or using a DC power supply consisting of a battery and converting the voltage into a boosted high voltage AC output. The object of the present invention is to provide a simple and efficient discharge lamp lighting device.

FIGS. 1 and 2 show a conventional example of a discharge lamp lighting device, in which E is a direct current power source, which is either rectified alternating current power or is provided with a battery.

Li, L2 are inductances, Tl, T2 are semiconductor switching elements made of transistors, and there are two sets of series circuits, one consisting of an inductance layer and a semiconductor switching element Tl, and the other series circuit consisting of an inductance L2 and a semiconductor switching element. It is connected in parallel to both ends of a DC power source E via a power switch s. A capacitor Cl is connected to both ends of one inductance Li, and a capacitor C2 is connected to both ends of the other inductance L2.
Further, the semiconductor switching elements Tl, T.

are each switching element Tl, T. Feedback diodes D, , D are connected in reverse parallel to the diodes D, , D for feedback. are connected, and the connection point A between one inductance thread and the semiconductor switching element Tl, and the connection point A between the other inductance thread and the semiconductor switching element T
. A series circuit of the discharge lamp l and a reactance xc made of, for example, a capacitor or inductance is connected between the connection point B and the discharge lamp l. The inductance Li, L
2 are provided with secondary windings nl, n2, whose outputs are first connected to semiconductor switching elements Tl, T through resistors , R2.

It is used as a control input. P is a startup panel generation circuit, which includes a resistor R, a capacitor Cs, and a switching element Q.
) consists of a diode Da.

Then, the winding of inductance Li, L) and the secondary winding n
, , the polarities of n2 are as shown in the figure. In such a discharge lamp lighting device, when the power switch S is turned on, the capacitor Cs is charged through the resistor R3, and its terminal voltage increases.

When this terminal voltage reaches the switching voltage of the switching element Q, the charge of the capacitor C is discharged through the semiconductor switching element T1, turning on the semiconductor switching element T1. Therefore, the inductance L from the DC power source E
1. Current flows through the semiconductor switching element T1,
When the semiconductor switching element T1 is turned off, vibration occurs in the closed circuit between the inductance thread and the capacitor C1, and as a result, vibration occurs between the terminals B and b'' of the secondary winding n1, which interlinks with a part of the magnetic flux of the inductance L1. The other group of semiconductor switching elements T2 is turned on from off by the voltage Vbb'', and the semiconductor switching elements T2 are kept on for a certain period of time, and current flows from the AC power supply E through the inductance L2 and the semiconductor switching element T2, and the semiconductor When switching element T2 turns off, inductance! , due to the vibration of the closed circuit of capacitor C2, the inductance L
The other semiconductor switching element T1 is turned on by the voltage Aa'' generated between the terminals A and a'' of the secondary winding j interlinking with a part of the magnetic flux of the secondary winding j. By repeating the above operation, both semiconductor switching elements Tl and T2 are turned on and off alternately, and a high voltage V3 is applied to the discharge lamp e via the reactance Xc by the induced electromotive force of the inductances Ll and L2.

By repeating ON and OFF operations of the semiconductor switching element T1, the electric charge of the capacitor C3 in the operating state is discharged through the diode D, and the switching element Q
remains off).

In the conventional discharge lamp lighting device, two sets of oscillating circuits are required to light one discharge lamp, which requires a large amount of materials and is not economical. The lamp voltage is determined by the characteristics of the discharge lamp itself and cannot exceed a predetermined voltage value.

Therefore, the voltage applied to the reactance Xc is the voltage V
3 and the lamp voltage, and the lower the lamp voltage, the greater the voltage applied to the reactance Xc, which is disadvantageous in terms of circuit efficiency. Furthermore, it is disadvantageous in terms of luminous efficiency that the lamp voltage does not exceed a predetermined value. In view of the above-mentioned reasons, the present invention provides a discharge lamp lighting device with a simple structure, which improves efficiency by increasing the lamp voltage and has good luminous efficiency.

3 to 4 show an embodiment of the present invention, in which first, second, third inductances Ll, l-. ,L3 and
First, second, and third semiconductor switching elements T each having parallel-connected diodes Dl, D2, and D3 for feedback current.
1, T2, and T3 are connected in parallel to both ends of the DC power source E, and the first, second, and third series circuits are
Each discharge lamp El, e2, e inserted between the inductance Ll, L, L3 and the connection point AB, BC, AC of the first, second, third semiconductor switching element Tl, T2, T3, respectively.
3 and reactances C4, C5, and C6 in series, and the three sets of first, second, and third inductances Ll, L2, and L3 are provided with secondary windings Nl and n2, respectively.
, and their outputs are used as alternating control inputs for the first, second, and third semiconductor switching elements Tl, T2, and T3, which are mutually connected to other sets of inductances Ll, L2, and L3,
It is constructed so that the induced electromotive force of each inductance element Ll, L2, L generated when the semiconductor switching elements Tl, T2, T3 are turned off is applied to the discharge lamps El, '2, e3, and any one of the semiconductor switching elements Element T
1 is a discharge lamp lighting device which is provided with a starting pulse generating circuit P which is turned on when the power is turned on. The starting pulse generating circuit P has a charging circuit including a resistor R4 and a capacitor C, which are charged by turning on a DC power source E,
The voltage across the capacitor C7 is detected by the switching element Q to turn on the set of first semiconductor switching elements T1, and when the first semiconductor switching element T1 repeatedly operates due to the alternating control input, The structure is such that the charge of C is discharged through the semiconductor switching element T1.

When the power switch S is turned on, the capacitor C7 is charged through the resistor R4, and when the terminal voltage of the capacitor C reaches the switching voltage of the switching element Q, the switching element Q is turned on and the first semiconductor of the first set is charged. Switching element T1 is turned on. Therefore, the first inductance L1, the first semiconductor switching element T
Current 11 flows through 1, but at the time shown in Fig.
When the semiconductor switching element T1 is turned off, vibration occurs in the closed circuit between the first inductance L1 and the capacitor C1. As a result, the voltage Va, a'' of the opposite polarity and reduced voltage generated between the terminals A, a'' of the secondary winding n1 interlinking with a part of the magnetic flux of the inductance thread causes the voltage Va, a'' of the second set to The base current 1B2 is supplied to the semiconductor switching element T2, and the second semiconductor switching element T2 is turned on from off. The second semiconductor switching element T2 is switched between n1 and T2.
Since it is turned on for a certain period of time, the second inductance from the DC power supply E! , a current flows through the second semiconductor switching element T2, and when the second semiconductor switching element T2 turns off at time t, the second inductance! , capacitor C
Vibration occurs in the closed circuit of the third set of A base current 1B3 is supplied to the semiconductor switching element T3, and the third
The semiconductor switching element T3 is activated at the time N. It remains on for a certain period of time from 2 to T3.

When the third semiconductor switching element T is turned on from off, the third inductance! , a current 13 flows through the third semiconductor switching element T3, but when the third semiconductor switching element T3 is turned off at a certain time, the third inductance! , vibration occurs in the closed circuit of the capacitor C3, and the first semiconductor switching is caused by the voltage Vcc' generated between the terminals cmc'' to the secondary winding interlinked with a part of the magnetic flux of the third inductance L, A base current 1B1 is supplied to the element T1, and the first semiconductor switching element T1 is turned on for a certain period of time from !1t3 to T.

When the first semiconductor switching element T1 is turned on from off, the first inductance! , a current 11 flows through the first semiconductor switching element T1, and when the first semiconductor switching element T1 is turned off at time ζ, the first
Vibration occurs in the closed circuit of the inductance L1 capacitor C1, and the voltage Vaa'' generated between the terminals a and a'' of the secondary winding n1, which interlinks with a part of the magnetic flux of the first inductance thread, causes the voltage to rise again. The base current I2 is supplied to the second semiconductor switching element T2, and the second semiconductor switching element T2 is turned on for a certain period of time.

Here, even when the voltages Vaa'', Vbb'', Cc'' between the terminals of the secondary windings Nl, rl2, n3 are negative, the collector currents 11, i2 of the semiconductor switching elements Tl, T2, T3 The reason why I3 flows will be explained with reference to FIG.

FIG. 6 is a waveform diagram related to the first semiconductor switching element T1, and the base-emitter voltage of the switching element T1 is as shown in FIG. 6e. Here, during the period t''3 from time T3 until the base current 1B1 starts flowing, the base current 1B1 becomes negative, and the period ``4'' is reverse biased by the oscillating voltage V3 caused by the third inductance L3 and the third capacitor C3. (The above-mentioned period ``3, t'' 4 is the secondary winding of the third inductance L3 ~
By changing the ratio of and changing the terminal voltage Vcc'',
In other words, the larger the terminal voltage Vcc'', the smaller it becomes)
. In addition, due to the turn-off time caused by a delay due to carrier accumulation of the collector current 11, the collector current 11 flows even immediately after the base current 1B1 becomes negative, and the collector current 11 flows for a period t''4.
After the effect, 11=0. Moreover, as mentioned above, the above-mentioned period t'' is actually much smaller than the one shown in the figure (for ease of understanding, it is smaller than the input vibration period which is shown long in FIGS. 4 and 6, so the switching element T1 is During the on period (from time to T4), the inductance L3
, which is half the natural oscillation period of the capacitor C3, and the switching element T1 is turned on and off in accordance with the oscillation period.

By repeating the above operations, the three sets of first, second, and third semiconductor switching elements Tl, T2, and T3 are alternately turned on and off, so that the first, second, and third inductances Ll
,L. , L3 voltage between connection points A-B due to induced electromotive force VABsB-C voltage VBClC-A voltage VCA
becomes a high-voltage AC voltage and the reactances C4, C5, C6
The voltage is applied to the discharge lamps El, e2, e3 through the circuit, lights up each of the three discharge lamps El, e2, e3, and turns on and off the first, second, and third semiconductor switching elements Tl, T2, and T3. The vibration period is set from several KHz to about 100 KHz.

Next, the collector current 11,i in FIGS. 2 and 4
The operation waveforms of 2 and i3 will be explained with reference to FIGS. 7 to 10. 1 Collector currents 11 and 12 in Figure 2 (conventional example) show an example of a heavy load (when the power consumption of the load is large); Currents 11, i2, and i3 indicate an example of a light load (when the power consumption of the load is small).

Therefore, if the conventional example is under a light load, the waveform will be as shown in FIG. 7b, and if the embodiment is under a heavy load, the waveform will be as shown in FIG. 8b.

2 In the period -T3 shown in Fig. 4, the feedback current 1D1 flows through the feedback diode D1, which is reverse biased by the negative voltage Vcc'' and connected in parallel with the transistor T1 (Fig. 9 and (See Figure 10).

In the case of FIG. 4, the period t″2 during which the transistor T1 is turned on
(see FIG. 10) is half the natural vibration period of the third inductance L3 and the capacitor C3.

(If Ll, Cl, L,, C2, L3, and C3 are set to the same value, the natural vibration period of Ll and Cl is the same, so
t″1=t″2. ) Compared to the case shown in Fig. 2, the period during which the transistor T1 is on is longer, and the electromagnetic energy of the inductance L1 at the time when the collector current is turned off is larger, so the voltage induced in the inductance thread is also larger, causing feedback. The period during which the current flows through the diode D1 is also increased.

(In the case of FIG. 2, the period in which the transistor T1 is turned off and the oscillating voltage is induced in the inductance L1 is almost the same as the combined period of the period in which the voltage flows through the transistor T1 and the feedback diode D1. In the case of FIG. 4, the period in which the current flows through the transistor T1 and the feedback diode D1 is longer.) Therefore, the above 1.
For the reason shown in FIG. 2, the collector currents 11, i2, and i3 become as shown in FIGS. 2 and 4.

FIG. 5 shows another embodiment of the present invention, in which P
'' is a starting pulse generation circuit, consisting of resistor R4 and capacitor C7.
and a reverse parallel circuit of two diodes D4 and D5 are connected in series to both ends of a DC power supply E obtained by rectifying the AC power supply Ac, and the series-parallel charging circuit is connected to the first and second charging circuits. , constitutes a bias circuit for the third semiconductor switching elements Tl, T2, and T3. Thus, the starting operation is carried out from the positive terminal of the full-wave rectifier Rec through the resistor R4 to each secondary winding N3,
nl, n2 and each semiconductor switching element Tl, T2
, base of T3. It is started by supplying current to the emitter. For example: When the polarity of the next winding j is forward bias, the resistance R1 → the base of the first semiconductor switching element T1. Turn on the semiconductor switching element T1 via the emitter → diode D4 → secondary winding j and resistor R1,
In the case of reverse bias, secondary winding N3→diode D5→emitter of first semiconductor switching element T1. Base →
Reverse bias is made by resistor R1 → secondary winding N3.

Note that the potential of the secondary winding j is higher than the on-voltage of the diode 8 due to the current flowing through the resistor R4 and the diode 8 and the negative potential of the full-wave rectifier Rec, making it easier to start. In this way, depending on the difference in the characteristics of the semiconductor switching elements Tl, T2, and T3, when one of the semiconductor switching elements is turned on and then turned off, the other semiconductor switching elements are turned on and off in sequence. will be activated. Incidentally, the filament circuits Fl, f2, f3 in this embodiment are connected to a preheating circuit (not shown).

Further, it is possible to use a bidirectional semiconductor switching element instead of the semiconductor switching element in each of the embodiments described above, and to operate the device without any problem even if the device is configured to be driven by an alternating current power source instead of a direct current power source. As described above, according to the present invention, the first, second, and third capacitors are connected in parallel.
Three series circuits each consisting of an inductance and a first, second, and third semiconductor switching element are connected in parallel to both ends of a DC power supply, and the first, second, and third inductances are connected to a diode for feedback current. An oscillating circuit is provided with a series circuit of three sets of discharge lamps and a reactance inserted between the respective connection points of the first, second, and third semiconductor switching elements connected in parallel, and each of the three sets of inductances has a series circuit. A secondary winding is provided and its output is used as an alternate control input for semiconductor switching elements that are mutually connected to other sets of inductances, and the induced electromotive force of each inductance generated when the semiconductor switching element is turned off is applied to the discharge lamp. By constructing the discharge lamp lighting device as shown in FIG. In the present invention, by adding one set of oscillating circuits, it is possible to light up only one discharge lamp by using two sets of oscillating circuits configured in series with a switching element and a feedback tie. It is possible to light a discharge lamp, and the voltage applied to each discharge lamp has a rest period.) When supplying power to a discharge lamp with high frequency operation, it is compared to a case without a rest period. Therefore, the present invention improves the circuit efficiency by increasing the lamp voltage compared to the conventional method, and eliminates a decrease in lamp luminous efficiency, making it possible to operate a discharge lamp in a simple and efficient manner. A device is obtained.

[Brief explanation of the drawing]

Figures 1 and 2 show a conventional discharge lamp lighting device.
The figure is a circuit diagram, and FIG. 2 is an operating waveform diagram. 3 to 5 show an embodiment of the discharge lamp lighting device of the present invention, FIG. 3 is a circuit diagram of one embodiment, FIG. 4 is a waveform diagram of each part operating, and FIG. 5 is a circuit of another embodiment. 6 is an operating waveform diagram of the first semiconductor switching device of the embodiment shown in FIG. 3, and FIGS. 7 to 10 illustrate differences in the operating waveforms of the collector current in FIGS. 2 and 4. FIG. 7 is a waveform diagram of the conventional example, FIG. 8 is a waveform diagram according to the present invention, FIG. 9 is a main circuit diagram, and FIG. 10 is an operation waveform diagram according to FIG. 9. . Ll, L,, L3...Inductance, Tl, T2, T,...Semiconductor switching element, P...Starting pulse generation circuit) Cl9C29C3 element $o capacitor ~ Dl9D29D3/O feedback diode, R4... Resistor, C7... Capacitor, C4, C5
, C6... Reactance.

Claims (1)

[Claims] 1. Three series circuits consisting of first, second, and third inductances in which capacitors are connected in parallel, and first, second, and third semiconductor switching elements in which diodes for feedback current are connected in parallel in opposite directions. a series circuit of three sets of discharge lamps and reactances connected in parallel to both ends of the DC power source and inserted between respective connection points of the first, second, and third inductances and the first, second, and third semiconductor switching elements; established,
Each of the three sets of inductances is provided with a secondary winding, and the output thereof is used as an alternate control input of a semiconductor switching element that is connected to the inductance of the other set, and each inductance generated when the semiconductor switching element is turned off. What is claimed is: 1. A discharge lamp lighting device configured to apply an induced electromotive force to a discharge lamp, and provided with a starting pulse generation circuit that turns on any one set of semiconductor switching elements when the power is turned on.