JPH0245316B2 - - Google Patents

Description

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

As shown in Fig. 1, a conventional discharge lamp multiple lighting device connects a series circuit of transistors S ₁ and S ₂ and a series circuit of capacitors C ₁ and C 2 in parallel to a DC power supply E, and connects a series circuit of transistors S 1 and S ₂ in parallel to ₁ , _S2 with diode _D1 , _D2
are connected so that they have opposite polarity to the transistors S ₁ and S ₂ , respectively, and an inductance L ₁ and a discharge are connected between the connection point A of the transistors S 1 _and S ₂ and the connection point of the capacitors C ₁ and C ₂ . The series circuit of the lamp LA ₁ is connected to the inductance L ₂ and the series circuit of the discharge lamp LA ₂ , respectively, and first and second secondary windings are provided which are electromagnetically coupled to the inductance L ₂ (the inductance L ₁ may also be used); These first and second secondary windings are connected with opposite polarities to each other between the base and emitter of transistors S ₁ and S ₂ via base resistors P _B1 and R _B2 , respectively, and are further connected to a DC power supply E through a resistor. R
Connect a series circuit of capacitor C and resistor R
A switch element Q having voltage responsiveness such as SSS or SBS is connected between the connection point of the capacitor C and the base of the transistor _S2 , and the discharge lamps _LA1 , _LA2 are connected.
Capacitors C ₃ and C ₄ for preheating are connected between both filaments of each. In this case, the resistor R, capacitor C and switch element Q constitute a starting path ST.

Next, the operation of this multiple discharge lamp lighting device will be explained. When the DC power supply E is turned on, the resistance R
Charge is accumulated in the capacitor C via the capacitor C. When the voltage on capacitor C reaches the breakover voltage of switch element Q, switch element Q becomes conductive and the charge on capacitor C is discharged through the base-emitter of transistor _S2 , causing a slight base current in transistor _S2 . flows and transistor _S2 becomes conductive. When transistor _S2 conducts, DC power supply E-
Capacitor C ₁ - series circuit of inductance L ₁ and discharge lamp LA ₁ and series circuit of inductance L ₂ and discharge lamp LA ₂ - transistor S ₂
- Current flows through the path of the DC power source E. After that, when the starting base current of transistor S ₂ becomes zero and transistor S ₂ is cut off, the induced voltage of inductance L ₂ is electromagnetically coupled to inductance L ₂ .
The next winding provides a forward bias to make transistor S ₁ conductive and a reverse bias to make transistor S ₂ conductive, causing transistor S ₁ to conduct and transistor S ₂ to shut off.

When transistor S ₁ becomes conductive and transistor S ₂ turns off, the inductance L ₁ ,
The electromagnetic energy stored in L ₂ is released,
Capacitor C ₁ - series circuit of inductance L ₁ and discharge lamp LA ₁ and series circuit of inductance L ₂ and discharge lamp LA ₂ - diode D ₁
- flows in the path of the capacitor C ₁ , then the DC power supply E - the transistor S ₁ - the series circuit of the inductance L ₁ and the discharge lamp LA ₁ and the series circuit of the inductance L ₂ and the discharge lamp LA ₂ - the capacitor C ₂ - the DC power supply E flows along the route of after that,
When the base current of transistor S ₁ becomes zero and transistor S ₂ is cut off, a forward bias is applied so that the induced voltage of inductance L ₂ is communicated to transistor S ₁ by the secondary winding which is electromagnetically coupled to inductance L ₂ . At the same time, a reverse bias is applied so that the transistor S ₁ is turned off, so that the transistor S ₂ is turned on and the transistor S ₁ is turned off.

When transistor S ₂ becomes conductive and transistor S ₁ is cut off, until then the inductance L ₁ ,
The electromagnetic energy stored in L ₂ is released,
Capacitor C ₂ − Diode D ₁ − Inductance
Series circuit of L ₁ and discharge lamp LA ₁ and series circuit of inductance L ₂ and discharge lamp LA ₂ −
A current flows in the path of the capacitor C ₂ , then in the path of the DC power supply E - the capacitor C ₁ - the series circuit of the inductance L ₁ and the discharge lamp LA ₁ and the series circuit of the inductance L ₂ and the discharge lamp LA ₂ - the transistor S ₂ Current flows.

After that, this operation is repeated and the transistors S ₁ and S ₂
conducts alternately, and a high-frequency current flows through the discharge lamps LA ₁ and LA ₂ , turning them on.

Figure 2 shows a waveform diagram of each part of the above-mentioned discharge lamp multiple lamp lighting device, and A and C are transistors, respectively.
Voltage between collector and emitter of S ₁ and S ₂ V _S1 and V _S2
, B and D are transistors S ₁ ,
The currents I _S1 and I _S2 flowing through S ₂ are E, and E is the discharge lamp.
is the current I _LA2 flowing through LA ₂ , F is the voltage V _L2 across the inductance L ₂ , and G and H are the bases I _B1 , I _B2 of the transistors S ₁ , S ₂ , respectively.

But in such a configuration, the discharge lamp LA ₂
When the lamp is removed or becomes unlit at the end of its life, current no longer flows through the inductance _L2 , the switching operation of the transistors _S1 and _S2 stops, and the discharge lamp _LA1 also stops lighting up. There was a problem. In addition, since the base drive signal is obtained from only the inductance L ₂ through the secondary winding, the discharge lamps LA ₁ and LA ₂ must be of the same standard.
Another drawback is that even if the inductances L ₁ and L ₂ are designed to the same specifications, the lamp powers of the discharge lamps LA ₁ and LA ₂ are different.

Therefore, an object of the present invention is to provide a multiple discharge lamp lighting device that can prevent other lamps from not lighting up when one lamp is not lit, and can also prevent power imbalance among the discharge lamps. be.

An embodiment of this invention is shown in FIG. In other words, this multiple discharge lamp lighting device has an inductance
L ₁ is also provided with first and second secondary windings, and the first secondary windings of each inductance L ₁ and L ₂ are connected in series in a positive manner, and each of the inductances L ₁ and L ₂ is The second secondary windings of are connected in series with added polarity, and the inductance L ₁ ,
The series circuit of the respective first secondary windings of L ₂ is connected to the base of the transistor S ₂ via the base resistor R _B2 .
Connect between emitters and inductance
The series circuit of the second secondary windings of L ₁ and L ₂ is made to have the opposite polarity to the series circuit of the first secondary winding, and the base of the transistor S ₁ is connected through the base resistor R _B1 .
It is connected between the emitters, and the other configuration is the same as that in FIG. 1.

In this multiple discharge lamp lighting device, when the DC power source E is turned on, the start circuit ST operates, and the transistor _S2 becomes conductive slightly and then shuts off. When transistor S ₂ is cut off, the inductances L ₁ , L ₂
An induced power is generated, and the voltage of the secondary winding electromagnetically coupled to the inductances L ₁ and L ₂ causes the transistors S ₁ and S ₂ to become conductive alternately, and the discharge lamps LA ₁ ,
LA ₂ lights up in the same way as the conventional example.

This will be explained in detail with reference to FIG. Fourth
In the figure, A indicates V _S1 between the collector and emitter of transistor S ₁ , B indicates current I _S1 flowing through transistor S ₁ , C indicates current I _LA1 flowing through discharge lamp LA ₁ , and D indicates inductance L ₂ E indicates the secondary winding voltage V _L2 ′ of the inductance L ₁ , and F indicates the combined voltage of the voltages V _L2 ′ and V _L1 ′ (V _L2 ′ ₊ V _L1 ′) , and G indicates a voltage whose polarity is reversed -(V _L1 ′+V _L2 ′).

When the transistor S ₁ is cut off and the transistor S ₂ is turned on at time t ₁ , the induced electromotive force of the inductances L ₁ and L ₂ causes the two of the inductances L ₁ and L ₂ to
A composite voltage of the next winding voltages V _L1 ′ and V _L2 ′ is applied between the base and emitter of transistors S ₁ and S ₂ with opposite polarities, and transistor S ₂ is given a forward bias and continues to conduct. ₁ is given a reverse bias and continues to block. Combined voltage of secondary winding
Until time t ₂ near when V _L1 ′+V _L2 ′ becomes zero due to the oscillating circuit, transistor S ₁ is cut off and the transistor
The state in which S ₂ continues to conduct.

Bias voltage V _L1 ′+ of transistor S ₂ at time t ₂
When V _L2 ′ becomes zero, transistor S ₂ begins to shut off, and when transistor S ₂ shuts off, induced power is generated in inductances L ₁ and L _{2 and} the transistor
Forward biasing S ₁ and transistor S ₂
A reverse bias is applied to transistor S ₁ and transistor S ₂ is turned off. Then, at a time t ₃ near when the secondary winding composite voltage V _L1 ′+V _L2 ′ becomes zero
This state will continue until.

At time _t3 , the states of transistors _S1 and _S2 are reversed by the same action as described above.

Thereafter, similarly, transistors S ₁ and S ₂ are alternately turned on and self-excited.

Here, if one of the discharge lamps LA ₁ and LA ₂ is removed or goes out of operation due to the end of the lamp life, etc., for example, when the discharge lamp LA ₁ goes out of operation, the inductance L ₁ Although no induced electromotive force is generated in the secondary winding (V _L1 ′≒0), induced electromotive force is generated in the secondary winding of inductance L ₂ , and this electromotive force causes the transistors S ₁ and S ₂ to They can be made conductive alternately, and the discharge lamp LA ₂ can be lit normally. Therefore, even if one discharge lamp LA ₁ or LA ₂ goes out, the other discharge lamp LA ₂ or LA ₁ will turn on, and the discharge lamps LA ₁ and LA ₂ will not completely go out. , it is also advantageous when lighting is thinned out. In addition, since the base drive signal is obtained from both inductances L ₁ and L ₂ , the lamp power of discharge lamps LA ₁ and LA ₂ can be made uniform without changing the specifications of inductances L ₁ and L ₂ as in the past. Because the variety of parts does not increase,
There are no design or manufacturing disadvantages.

Another embodiment of the invention is shown in FIG. In other words, this multiple discharge lamp lighting device connects the connection point B of the capacitors C ₁ and C ₂ in FIG. 1 and the inductances L ₁ and L ₂
An inductance L ₃ is inserted between the common connection point of the inductance L ₃ , and the base drive signals of the transistors S ₁ and S ₂ are taken out from the first and second secondary windings provided on the inductance L ₃ . The secondary winding has been removed, and the rest is the same as that shown in FIG.

In this example, two types of inductance L ₁ ,
Although L ₂ and L ₃ are required, it is possible to prevent other lamps from not lighting up in a single lamp lighting area, and each discharge lamp
Power imbalance between LA ₁ and LA ₂ can be prevented.

As described above, the multiple discharge lamp lighting device of the first invention includes a DC power supply, a series circuit of first and second switching elements connected between both ends of the DC power supply, and a series circuit of the first and second switching elements connected between both ends of the DC power supply. a series circuit of first and second capacitors connected to each other, and a first capacitor connected in parallel to each other between a connection point of the first and second switching elements and a connection point of the first and second capacitors. A series circuit of a discharge lamp and a first inductance element, and a series circuit of a second discharge lamp and a second inductance element, each attached to the first and second inductance elements and connected in series with polarity. the first and second windings connected to the control input terminal of the first switching element, and the first and second inductance elements in a state of opposite polarity to the first and second windings, respectively. and third and fourth windings respectively attached to and connected to the control input terminal of the second switching element in a positive series-connected state, and in particular, a third and fourth winding wire connected in series to the first discharge lamp. The voltage obtained by adding the first and second winding voltages attached to the first inductance element connected in series to the first inductance element and the second inductance element connected in series to the second discharge lamp is the first voltage.
is applied to the control input terminal of the switching element, and the voltages of the third and fourth windings attached to the first and second inductance elements, respectively, with opposite polarity to the first and second windings, are added to the polarity. Since the combined voltage is applied to the control input terminal of the second switching element, even if one lamp goes out and the lamp current stops flowing, the first and second switching elements
It is possible to continue supplying the control signal to the switching element of the switch, and therefore, it is possible to prevent other lights from being turned off when one lamp is turned off. Moreover, a winding is attached to each of the first and second inductance elements connected in series to the first and second discharge lamps,
Since they are combined into an additive signal to form a control signal, it is possible to eliminate load imbalance and prevent power imbalance among the discharge lamps.

Furthermore, for example a first discharge lamp or a first
When the current flowing through the first discharge lamp increases or decreases due to variations in the characteristics of the inductance element or the starting element provided for starting the first discharge lamp, the current flowing through the first discharge lamp increases or decreases. The voltages of the first and third windings vary, and accordingly, the combined voltage of the first and second windings and the combined voltage of the third and fourth windings, that is, the voltage of the first and second switching elements. The control voltage changes in the same way, and the variation in characteristics of the first discharge lamp, the first inductance element, or the starting element provided for starting the first discharge lamp is affected by the second discharge. This will be transmitted to the lamp in the same way, and if the polarity and voltage value of the induced voltage in the first to fourth windings are set appropriately, the current flowing in the first discharge lamp and the current flowing in the second discharge lamp will be The flowing current can be made equal, and the difference in brightness between the first and second discharge lamps can be reduced.

Further, the multiple discharge lamp lighting device of the second invention includes a DC power source and a first power source connected between both ends of the DC power source.
and a series circuit of a second switching element, a series circuit of first and second capacitors connected across the DC power supply, and a connection point between the first and second switching elements and the first and second capacitors. 2
a first inductance element having one end connected to the connection point of the capacitor, and the other end of the inductance element connected to the connection point of the first and second switching elements and the connection point of the first and second capacitors; a series circuit of a first discharge lamp and a second inductance element, and a series circuit of a second discharge lamp and a third inductance element connected in parallel between the other end of the first inductance element; a first winding attached to the inductance element and connected to the control input terminal of the first switching element; and a second winding attached to the first inductance element and having a polarity opposite to that of the first winding. and a second winding connected to the control input terminal of the switching element of the first invention. This is equivalent to providing the first to fourth windings on the and second inductance elements, and connecting them as described above to the control input terminals of the first and second switching elements. The same effect as that of invention 1 can be achieved.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional multiple discharge lamp lighting device.
2A to 2H are waveform diagrams of each part, FIG. 3 is a circuit diagram of an embodiment of this invention, FIGS. 4A to 4H are waveform diagrams of each part, and FIG. 5 is another embodiment of this invention. FIG. 3 is an example circuit diagram. E...DC power supply, _S1 , _S2 ...Transistor (switching element), _C1 , _C2 ...Capacitor, _LA1 ,
LA ₂ ... discharge lamp, L ₁ , L ₂ , L ₃ ... inductance.

Claims (1)

[Claims] 1. A series circuit of a DC power source, first and second switching elements connected across the DC power source, and first and second capacitors connected across the DC power source. a series circuit, a first discharge lamp and a first inductance element connected in parallel with each other between a connection point of the first and second switching elements and a connection point of the first and second capacitors; a series circuit of a circuit, a second discharge lamp and a second inductance element, and a control input terminal of the first switching element attached to the first and second inductance elements respectively and connected in series with polarity; first and second windings connected to the first and second inductance elements, respectively attached to the first and second inductance elements and connected in series with polarity opposite to the first and second windings, respectively; and third and fourth windings connected to a control input terminal of the second switching element in a switching state. 2. a DC power supply, a series circuit of first and second switching elements connected across the DC power supply, a series circuit of first and second capacitors connected across the DC power supply, and a series circuit of the first and second switching elements connected across the DC power supply; a first inductance element having one end connected to one of a connection point between the first and second switching elements and a connection point between the first and second capacitors, and a connection point between the first and second switching elements; Said first
and a series circuit of a first discharge lamp and a second inductance element connected in parallel between the other end of the connection point of the second capacitor and the other end of the first inductance element; a series circuit of a third inductance element;
a first winding attached to the first inductance element and connected to a control input terminal of the first switching element; and a first winding attached to the first inductance element with a polarity opposite to that of the first winding. and a second winding connected to a control input terminal of the second switching element.