JPH09232092A - High pressure discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost in a high pressure discharge lamp lighting device to light a high pressure discharge lamp. SOLUTION: Voltage of an input coil W1 is inputted and cut off by a transistor Q5 , and voltage is generated in driving coils W3a , W3b , W3c and W3d , and bipolar transistors BT1 and BT3 or bipolar transistors BT2 , and BT4 are turned on by voltage of respective capacitors Co connected to them, and its ON operation is alternately repeated, and AC voltage having a rectangular wave is supplied to a high pressure discharge lamp LP, and it is lighted. An ON resistance of a transistor Q7 is controlled according to terminal voltage of the high pressure discharge lamp LP, and ON time of the transistor Q5 is controlled, and voltage of the capacitors Co is controlled, and a driving condition of the bipolar transistors BT1 , BT2 , BT3 and BT4 is made always proper.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal halide
The present invention relates to a high pressure discharge lamp lighting device for lighting a high pressure discharge lamp such as a lamp.

[0002]

2. Description of the Related Art In a high pressure discharge lamp lighting device for lighting a high pressure discharge lamp such as a metal halide lamp, an electronic circuit ballast using a semiconductor circuit has been widely used in order to reduce its size and weight. 3 and 4 are half parts of a circuit diagram showing a configuration of a conventional high pressure discharge lamp lighting device of this type.

The AC power supply AC is connected to the AC input terminals 1a and 1b of the rectifying bridge 1. A smoothing capacitor C is placed between the DC positive voltage terminal 1c and the DC negative voltage terminal 1d of the rectifying bridge 1.
₁ and a smoothing capacitor C ₂ are connected in series, and the intermediate point of connection between the smoothing capacitors C ₁ and C ₂ is the AC input terminal 1b.
Connected to The DC positive and negative voltage terminals 1c and 1d are respectively connected to the positive and negative voltage input terminals 2a and 2b of the power control circuit 2. The positive and negative voltage output terminals 2c and 2d of the power control circuit 2 are respectively the positive and negative voltage input terminals 3 of the starter pulse generation circuit 3.
Connected to a and 3b. A series circuit of a capacitor C ₃ and a capacitor C ₄ is interposed between the positive and negative voltage output terminals 2c and 2d, and the power MOSFET Q is connected to each of the capacitors C ₃ and C _4.
1 and Q ₂ are connected in parallel. The drain of the power MOSFET Q _{1 corresponds to} the positive voltage output terminal 2c, and the source of the power MOSFET Q ₂ corresponds to the negative voltage output terminal 2d.

Between the positive and negative voltage output terminals 2c and 2d,
Indexer C_FiveAnd capacitor C₆The series circuit with
Capacitor C_Five, C₆Power MOSFET Q for each_Four,
Q_ThreeAre connected in parallel. Power MOSFET Q_FourDrain of
Is the positive voltage output terminal 2c and the power MOSFET Q_ThreeThe source of is negative
It corresponds to the voltage output terminal 2d. Power MOSFET Q₁And Q
_TwoIntermediate point of connection with capacitor C_FiveAnd C₆Connecting with
Between the point and the transformer T₁Secondary winding T_W2And high pressure release
A series circuit with the electric lamp LP is interposed. Transformer T ₁Of 1
Next winding T_W1Each terminal of the starter pulse generation circuit 3
Each is connected to the starter pulse output terminals 3c and 3d of.

A light emitting diode PD1 of a photocoupler PC1 is interposed between the first oscillation output terminals 4a and 4b of the oscillation circuit 4. Phototransistor PT _a is connected in series to receive light emitting diodes PD1, the emitter of phototransistor PT _a of PT _b is connected to the connection point between the power MOSFET Q ₁ and Q _2, and the collector of the phototransistor PT _a An intermediate connection point between the light receiving transistor PT _{b and} the emitter is connected to the gate of the power MOSFET Q ₁ via the resistor R ₁ .

A light emitting diode PD2 of a photocoupler PC2 is interposed between the second oscillation output terminals 4c and 4d of the oscillation circuit 4.
Phototransistor PT _a is connected in series to receive light emitting diodes PD2, the emitter of phototransistor PT _a of PT _b is connected to the negative voltage output terminal 2d of the power control circuit 2, the light receiving and the collector of phototransistor PT _a An intermediate connection point between the transistor PT _{b and} the emitter is connected to the gate of the power MOSFET Q ₂ via the resistor R ₂ .

A light emitting diode PD3 of a photocoupler PC3 is interposed between the third oscillation output terminals 4e and 4f of the oscillator circuit 4.
Series-connected phototransistor PT _a receiving light emitting diode PD3, the emitter of phototransistor PT _a of PT _b is connected to the negative voltage output terminal 2d of the power control circuit 2, the light receiving and the collector of phototransistor PT _a An intermediate connection point between the transistor PT _{b and} the emitter is connected to the gate of the power MOSFET Q ₃ via the resistor R ₃ .

A light emitting diode PD4 of a photocoupler PC4 is interposed between the third oscillation output terminals 4g and 4h of the oscillator circuit 4.
Phototransistor PT _a is connected in series to receive light emitting diodes PD4, the emitter of phototransistor PT _a of PT _b is connected to the connection point between the power MOSFET Q ₃ and Q _4, and the collector of the phototransistor PT _a An intermediate connection point between the light receiving transistor PT _{b and} the emitter is connected to the gate of the power MOSFET Q ₄ via the resistor R ₄ .

The DC positive voltage terminal 1c of the rectifying bridge 1 is connected to one terminal of the input winding W ₁ of the switching transformer T ₂ , and is connected to the base of the transistor Q ₅ via the resistor R ₁₀ . The other terminal of the input winding W ₁ is a transistor Q
Connected with ₅ collectors. The base of the transistor Q ₅ is connected to the collector of the transistor Q ₆ , and the resistor R
It is connected to one side terminal of the auxiliary winding W ₂ through a series circuit of ₁₁ and a diode D ₂ having its cathode connected. A series circuit of a resistor R ₁₅ and a capacitor C ₁₂ is connected in parallel to the diode D ₂ . An intermediate connection point between the anode of the diode D ₂ and the capacitor C ₁₂ is connected to the base of the transistor Q ₆ via the resistor R ₁₂ . The emitters of the transistors Q ₅ and Q ₆ are connected to the DC negative voltage terminal 1d and the other side terminal of the auxiliary winding W ₂ , respectively.

Further, the transistor Q₆The base of the resistance R
₁₄And capacitor C₁₁Transistor through parallel circuit with
Q₆Connected to the emitter of the resistor R₁₃Through the transition
Star Q₇Connected with the collector of. Transistor Q₇of
The emitter drives the power control circuit 2 of the power control circuit 2.
It is connected to the power supply voltage input terminal 2e that gives voltage, and the resistance R ₁₄
Through transistor Q₇Connected with the base of. Tiger
Transistor Q₇The base has a cathode connected to it
Auxiliary winding W via Zener diode ZD_TwoOther end
Connected with child. Switching transformer T_TwoFirst drive
Winding W_3a, The second drive winding W_3b, The third drive winding W_3c, 4th
Drive winding W_3dA diode D is placed between the terminals.₀And con
Densa C₀A series circuit of and is interposed.

Each terminal of the capacitor C ₀ connected to the first drive winding W _3a is connected to the light receiving transistor PT of the photocoupler PC 1.
It is connected to the terminals on both sides of the series circuit of _a and PT _b . Second
Each terminal of the capacitor C ₀ connected to the drive winding W _3b is
Phototransistor PT _a photocouplers PC2, both sides of the terminals of the series circuit of PT _b, and the light receiving transistor PT _a photocouplers PC3, are each connected to both sides of the terminal of the series circuit of PT _b.
Each terminal of the capacitor C ₀ connected to the third drive winding W _3c is connected to the terminals on both sides of the series circuit of the light receiving transistors PT _a and PT _b of the photocoupler PC3. One terminal of the capacitor C ₀ connected to the fourth drive winding W _3d is connected to the other terminal of the auxiliary winding W ₂ , and the middle point of connection between the other terminal of the capacitor C ₀ and the diode D ₀ is a transistor. Connected to the emitter of Q ₇ .

Each of the photocouplers PC1, PC2, PC3, PC4 is designed so that when one of the light receiving transistor PT _a and the light receiving transistor PT _b is on (off), the other is off (on). The oscillating circuit 4 oscillates so that the light emitting diode
When PD1 and PD3 are made to emit light (non-light emission), light emitting diode
Set PD2 and PD4 to non-light emission (light emission), and light emitting diodes PD1 and PD
The light emission of 3 and the light emission of the light emitting diodes PD2 and PD4 are alternately repeated.

Next, the operation of the high pressure discharge lamp lighting device will be described.
I do. The voltage of AC power supply AC is input to the rectification bridge
After full-wave rectification or voltage doubler rectification, the capacitor
C₁, C _TwoThe DC voltage smoothed by the power control circuit
2 is input. The power control circuit 2 is a high pressure discharge lamp described later.
The power to be supplied to the LP was controlled to be kept at a predetermined value
Outputs DC voltage. Direct output from the power control circuit 2
Current voltage is power MOSFET Q ₁, Q_TwoSeries circuit, power
MOSFET Q_Three, Q_FourSeries circuit and starter pulse generation times
It is supplied to the path 3, and the starter pulse generation circuit 3 discharges high voltage.
High level of several kV to several tens of kV for a predetermined time until the light LP is turned on
Generate a pressure pulse. This high voltage pulse is transformer T₁To
It is supplied to the high pressure discharge lamp LP via.

On the other hand, the DC positive voltage terminal 1c of the rectifying bridge 1
Is input to the base of the transistor Q ₅ via the resistor R ₁₀ to turn on the transistor Q ₅ . Then,
A DC voltage is supplied to the input winding W ₁ of the switching transformer T ₂ , and the auxiliary winding W ₂ and the first drive winding W _3a
A voltage is generated in the drive winding W _3b , the third drive winding W _3c , and the fourth drive winding W _3d . Then, the voltage of the auxiliary winding W ₂ changes to the resistance R ₁₂
And is integrated by the capacitor C _11, a sawtooth wave voltage generated is integrated is input to the base of the transistor Q _6, transistor Q ₆ reaches a predetermined voltage is turned on. Base voltage of the transistor Q ₅ the transistor Q ₆ is turned on is turned off the transistor Q ₅ decreases.

The fourth drive winding W_3dConnected to
Densa C₀The voltage generated at the resistor R ₁₄Through the transition
Star Q₇Input to the base of the transistor Q₇But
On. And transistor Q₇From the collector of
Transistor Q₇Impedance between collector and emitter
A DC voltage that is inversely proportional to the barrel ON resistance is output and the resistance R
₁₃Through transistor Q₆Input to the base of. One
Mari, transistor Q ₆The base voltage of the DC voltage is sawtooth
It becomes the voltage that the superposed wave voltage, and the transistor Q₇No
Transistor Q due to DC voltage₆Is on
The timing to do it changes.

The first drive winding W _3a and the second drive winding W _3
The voltage generated in _3b , the third drive winding W _3c , and the fourth drive winding W _3d does not charge the capacitor C ₀ while the anode of the diode D ₀ is a negative voltage, and becomes a positive voltage. Charge the capacitor C ₀ . The voltage of each of the capacitors C ₀ , C ₀ , C ₀ charged in this way is determined by the photocouplers PC1, PC2,
It is supplied to the series connection circuit of the light receiving diodes of PC3 and PC4. Here, the oscillation circuit 4 oscillates and the light emitting diode
When PD1 and PD3 are emitting light, light emitting diodes PD2 and PD
When 4 is not emitting light and the light emitting diodes PD1 and PD3 are not emitting light, the operation of causing the light emitting diodes PD2 and PD4 to emit light is alternately repeated. As a result, photocouplers PC1 and PC
3 is input a voltage of the capacitor C ₀ is the base of the power MOSFET Q _1, Q ₃ when on the power MOSFET Q _1, Q ₃
Turns on. The time photocoupler PC2, PC 4 is on, the input voltage of the capacitor C ₀ to the base of the power MOSFET Q _2, Q ₄ and the power MOSFET Q _2, Q ₄ are turned on.

The voltage of the capacitor C ₀ connected to the fourth drive winding W _3d is the power supply voltage input terminal of the power control circuit 2.
The electric power control circuit 2 controls the lighting power of the high pressure discharge lamp LP to be constant by being input to 2e. When the power MOSFETs Q ₁ and Q ₃ are turned on as described above, the voltage between the positive and negative voltage output terminals 2c and 2d of the power control circuit 2 becomes the power.
It is supplied via the MOSFETs Q ₁ and Q ₃ and a positive voltage is supplied to one terminal of the high pressure discharge lamp LP. Also power MOSFET
Q _2, by Q ₄ is turned on, the positive power control circuit 2, a negative voltage output terminal 2c, the voltage between 2d is a power MOSFET
It is supplied via Q ₂ and Q ₄ , and a negative voltage is supplied to one terminal of the high pressure discharge lamp LP. Such an operation is repeated alternately, and a rectangular wave AC voltage is supplied to the high-pressure discharge lamp LP.

The high pressure pulse applied to the high pressure discharge lamp LP and the voltage supplied from the power control circuit 2 cause the high pressure discharge lamp LP to light up. When the high-pressure discharge lamp LP is turned on, the high-voltage pulse output from the starter pulse generation circuit 3 disappears, and the high-voltage discharge lamp LP is supplied with stable electric power due to the rectangular wave AC voltage corresponding to the DC voltage supplied from the power control circuit 2. Keeps lighting.

[0019]

By the way, the terminal voltage of a high pressure discharge lamp such as a metal halide lamp is about 20V from the time immediately after the high pressure discharge lamp is lit up until a few minutes elapse.
Although it is a low voltage, the terminal voltage rises as the vapor pressure in the high-pressure discharge lamp rises, and rises to a predetermined terminal voltage after a few minutes. The current flowing through the high-pressure discharge lamp during this period is about twice as large as that during lighting after the initial lighting, because the power control circuit operates to keep the power supplied to the high-pressure discharge lamp substantially constant. Becomes the current of.

As an example, the high pressure discharge lamp power is 250 W,
In the case of a high-voltage discharge lamp with a terminal voltage of 70 V, the terminal voltage of the high-pressure discharge lamp is 20 V and the current of the high-pressure discharge lamp is 5.7 A at the beginning of lighting, which is about 1.6 times that at the time of lighting after the initial lighting. The current of this high-pressure discharge lamp then flows to the drain of the power MOSFET. For this reason, the power MOSFET is used. However, since the power MOSFET is expensive, it is originally desirable to use an inexpensive bipolar transistor, but since the current change of the high pressure discharge lamp changes nearly twice,
If the driving voltage of the bipolar transistor is constant, the bipolar transistor will generate heat abnormally and cannot be used.

That is, if the driving condition of the bipolar transistor is designed in accordance with the stable lighting after the initial lighting, the bipolar transistor is insufficiently driven in the initial lighting, and the bipolar transistor is destroyed due to abnormal heat generation. On the other hand, if the driving conditions are matched at the initial stage of lighting, excessive driving is performed at the time of stable lighting after the initial stage of lighting, resulting in increased switching loss and abnormal oscillation due to poor switching control. Therefore, when the bipolar transistor is used, it is difficult to optimize the driving conditions, and the power MOSFET is inevitably used, which causes an increase in cost of the high pressure discharge lamp lighting device. An object of the present invention is to provide an inexpensive high pressure discharge lamp lighting device capable of lighting a high pressure discharge lamp by using a bipolar transistor as a switch element for supplying an AC voltage to the high pressure discharge lamp, and reducing costs. To do.

[0022]

A high-pressure discharge lamp lighting device according to a first aspect of the present invention is configured so that a DC voltage obtained by rectifying an AC voltage is supplied to a high-pressure discharge lamp via a switch element, and is generated by the DC voltage. In the high pressure discharge lamp lighting device for applying the driving voltage to the switch element, and driving the switch element to light the high pressure discharge lamp, a bipolar transistor is used for the switch element,
The driving voltage is changed according to the terminal voltage of the high pressure discharge lamp.

According to the first aspect of the invention, when the bipolar transistor is driven to supply an alternating voltage to the high pressure discharge lamp, the high pressure discharge lamp is turned on. When the voltage for driving the bipolar transistor is changed according to the terminal voltage of the high-pressure discharge lamp, the driving condition of the bipolar transistor does not change during the initial lighting of the high-pressure discharge lamp and during stable lighting after the initial lighting, and the bipolar transistor is in a proper state. It is maintained, the bipolar transistor does not generate heat, and the switching loss does not increase. Thus, even if a bipolar transistor is used to supply a voltage to the high pressure discharge lamp, it will not be destroyed.

The high-pressure discharge lamp lighting device according to the second aspect of the invention is configured to supply a DC voltage obtained by rectifying an AC voltage to the high-pressure discharge lamp via a switch element, and the drive voltage generated by the DC voltage is In a high-pressure discharge lamp lighting device for lighting a high-pressure discharge lamp by applying it to a switch element, a bipolar transistor is used for the switch element, and the drive voltage is a terminal voltage of the high-pressure discharge lamp. It is characterized in that it is provided with a transistor which is changed in accordance with the condition.

In the second aspect of the invention, when the bipolar transistor is driven to supply an alternating voltage to the high pressure discharge lamp, the high pressure discharge lamp is turned on. When the voltage for driving the bipolar transistor is changed according to the terminal voltage of the high-pressure discharge lamp by the transistor, the driving condition of the bipolar transistor does not change at the initial lighting of the high-pressure discharge lamp and at the time of stable lighting after the initial lighting. The bipolar transistor does not generate heat and the switching loss does not increase.
Thus, even if a bipolar transistor is used to supply a voltage to the high pressure discharge lamp, it will not be destroyed.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments of the present invention. 1 and 2 are half of the circuit diagram showing the configuration of the high pressure discharge lamp lighting device according to the present invention. The AC power supply AC is the AC input terminal 1 of the rectifying bridge 1.
Connected to a, 1b. DC positive voltage terminal 1 of rectifier bridge 1
A series circuit of a smoothing capacitor C ₁ and a smoothing capacitor C ₂ is interposed between the c and the DC negative voltage terminal 1d, and a connection intermediate point between the smoothing capacitors C ₁ and C ₂ is connected to the AC input terminal 1b. . The DC positive and negative voltage terminals 1c and 1d are respectively connected to the positive and negative voltage input terminals 2a and 2b of the power control circuit 2. The positive and negative voltage output terminals 2c and 2d of the power control circuit 2 are connected to the positive and negative voltage input terminals 3a and 3b of the starter pulse generation circuit 3, respectively. A series circuit of a capacitor C ₃ and a capacitor C ₄ is provided between the positive and negative voltage output terminals 2c and 2d, and a bipolar transistor BT is provided in each of the capacitors C ₃ and C _4.
1 , BT ₂ are connected in parallel. The collector of the bipolar transistor BT _{1 corresponds to} the positive voltage output terminal 2c, and the emitter of the bipolar transistor BT ₂ corresponds to the negative voltage output terminal 2d.

In addition, between the positive and negative voltage output terminals 2c and 2d,
Indexer C_FiveAnd capacitor C₆The series circuit with
Capacitor C_Five, C₆Each has a bipolar transition
Star BT_Four, BT_ThreeAre connected in parallel. Bipolarto
Langista BT_FourOf the positive voltage output terminal 2c
Ipolar transistor BT_ThreeThe emitter of is a negative voltage output terminal
It corresponds to child 2d. Bipolar transistor BT₁When
BT_TwoIntermediate point of connection with capacitor C_FiveAnd C₆Contact with
The transformer T is connected to the continuation midpoint.₁Secondary winding T _W2And high
A series circuit with the pressure discharge lamp LP is interposed. Transformer T₁
Primary winding T_W1Each terminal of the
Each is connected to the starter pulse output terminals 3c and 3d of the path 3.

A light emitting diode PD1 of a photocoupler PC1 is interposed between the first oscillation output terminals 4a and 4b of the oscillation circuit 4. Phototransistor PT _a is connected in series to receive light emitting diodes PD1, the emitter of phototransistor PT _a of PT _b is connected to the connection point between the bipolar transistor BT ₁ and BT _2, the collector of the phototransistor PT _a An intermediate connection point between the light receiving transistor PT _{b and} the emitter of the light receiving transistor PT _b is connected to the base of the bipolar transistor BT ₁ via the resistor R ₁ .

A light emitting diode PD2 of a photocoupler PC2 is interposed between the second oscillation output terminals 4c and 4d of the oscillation circuit 4.
Phototransistor PT _a is connected in series to receive light emitting diodes PD2, the emitter of phototransistor PT _a of PT _b is connected to the negative voltage output terminal 2d of the power control circuit 2, the light receiving and the collector of phototransistor PT _a The midpoint of the connection of the transistor PT _{b with} the emitter is connected with the base of the bipolar transistor BT ₂ via the resistor R ₂ .

A light emitting diode PD3 of a photocoupler PC3 is interposed between the third oscillation output terminals 4e and 4f of the oscillation circuit 4.
Series-connected phototransistor PT _a receiving light emitting diode PD3, the emitter of phototransistor PT _a of PT _b is connected to the negative voltage output terminal 2d of the power control circuit 2, the light receiving and the collector of phototransistor PT _a The midpoint of the connection of the transistor PT _{b with} the emitter is connected with the base of the bipolar transistor BT ₃ via the resistor R ₃ .

A light emitting diode PD4 of a photocoupler PC4 is interposed between the fourth oscillation output terminals 4g and 4h of the oscillation circuit 4.
Phototransistor PT _a is connected in series to receive light emitting diodes PD4, the emitter of phototransistor PT _a of PT _b is connected to the connection point between the bipolar transistor BT ₃ and BT _4, the collector of the phototransistor PT _a An intermediate connection point between the light receiving transistor PT _{b and} the emitter of the light receiving transistor PT _b is connected to the base of the bipolar transistor BT ₄ via the resistor R ₄ .

The DC positive voltage terminal 1c of the rectifying bridge 1 is connected to one terminal of the input winding W ₁ of the switching transformer T ₂ and is connected to the base of the transistor Q ₅ via the resistor R ₁₀ . The other terminal of the input winding W ₁ is a transistor Q
Connected with ₅ collectors. The base of the transistor Q ₅ is connected to the collector of the transistor Q ₆ , and the resistor R
It is connected to one side terminal of the auxiliary winding W ₂ through a series circuit of ₁₁ and a diode D ₂ having its cathode connected. A series circuit of a resistor R ₁₅ and a capacitor C ₁₂ is connected in parallel to the diode D ₂ . An intermediate connection point between the anode of the diode D ₂ and the capacitor C ₁₂ is connected to the base of the transistor Q ₆ via the resistor R ₁₂ . The emitters of the transistors Q ₅ and Q ₆ are connected to the DC negative voltage terminal 1d and the other side terminal of the auxiliary winding W ₂ , respectively.

The base of the transistor Q ₆ is a resistor R
_It is connected to the emitter of the transistor Q ₆ through a parallel circuit of ₁₄ and the capacitor C _11, and directly connected to the emitter of the transistor Q ₇ . The collector of the transistor Q ₇ is connected to the power supply voltage input terminal 2e that supplies a voltage for driving the power control circuit 2 of the power control circuit 2.

Transistor Q₇Is a resistor R₂₀Through
Then auxiliary winding W_TwoIs connected to the other side terminal of the resistor R_{twenty one}When,
Diode D connecting the anode to it_ThreeAnd die
Aether D_ThreeZener connecting cathode to cathode
-Auxiliary winding W via series circuit with diode ZD_Twoof
Connected to the other terminal. Auxiliary winding W_TwoBetween the terminals on the other side
Is a diode D whose anode is connected to one terminal
₁And capacitor C₁₃A series circuit with is inserted. Daio
Code D₁Cathode and capacitor C₁₃Midpoint of connection with
Is the resistance R₁₆And the Zener connecting the cathode to it
-Diode ZD _TwoThrough a series circuit with a transistor
Q₇Connected with the base of. Resistance R_{twenty one}And diode D_Three
The middle point of connection with is resistance R_{twenty two}Through the power control circuit 2
It is connected to the voltage output terminal 2c. Switching transformer T
_TwoFirst drive winding W of_3a, The second drive winding W_3b, 3rd drive winding
Line W_3c, 4th drive winding W_3dBetween each terminal,
Do D ₀And capacitor C₀A series circuit of and is interposed.

Each terminal of the capacitor C ₀ connected to the first drive winding W _3a is connected to the light receiving transistor PT of the photocoupler PC1.
It is connected to the terminals on both sides of the series circuit of _a and PT _b . Second
Each terminal of the capacitor C ₀ connected to the drive winding W _3b is
Phototransistor PT _a photocouplers PC2, both sides of the terminals of the series circuit of PT _b, and the light receiving transistor PT _a photocouplers PC3, are each connected to both sides of the terminal of the series circuit of PT _b.
Each terminal of the capacitor C ₀ connected to the third drive winding W _3c is connected to each terminal on both sides of the series circuit of the light receiving transistors PT _a and PT _b of the photocoupler PC3. 4th drive winding W _3d
One terminal of the capacitor C ₀ connected to is the auxiliary winding W ₂
Is connected to the other side terminal, and the midpoint of connection between the other side terminal of the capacitor C ₀ and the diode D ₀ is connected to the collector of the transistor Q ₇ .

Each of the photocouplers PC1, PC2, PC3, and PC4 is designed so that when one of the light receiving transistor PT _a and the light receiving transistor PT _b is on (off), the other is off (on). The oscillating circuit 4 causes the light emitting diode to
When PD1 and PD3 are made to emit light (non-light emission), light emitting diode
The PD2 and PD4 are made non-emissive, and the light emission of the light emitting diodes PD1 and PD3 and the light emission of the light emitting diodes PD2 and PD4 are alternately repeated.

Next, the operation of the high pressure discharge lamp lighting device will be described.
I do. The voltage of AC power supply AC is input to the rectification bridge
After full-wave rectification or voltage doubler rectification, the capacitor
C₁, C _TwoThe DC voltage smoothed by the power control circuit
2 is input. The power control circuit 2 is a high pressure discharge lamp described later.
The power to be supplied to the LP was controlled to be kept at a predetermined value
Outputs DC voltage. Direct output from the power control circuit 2
Current voltage is bipolar transistor BT₁, BT_TwoDirectly
Column circuit, bipolar transistor BT_Three, BT_FourSeries
Supplied to the circuit and starter pulse generation circuit 3,
The pulse generator circuit 3 waits until the high-pressure discharge lamp LP lights up.
A high voltage pulse of several kV to several tens of kV is generated for a predetermined time. This
High voltage pulse of transformer T₁To the high pressure discharge lamp LP via
Supplied.

On the other hand, the DC positive voltage terminal 1c of the rectifying bridge 1
Is input to the base of the transistor Q ₅ via the resistor R ₁₀ to turn on the transistor Q ₅ . Then,
A DC voltage is supplied to the input winding W ₁ of the switching transformer T ₂ , and the auxiliary winding W ₂ and the first drive winding W _3a
A voltage is generated in the drive winding W _3b , the third drive winding W _3c , and the fourth drive winding W _3d . Then, the voltage of the auxiliary winding W ₂ changes to the resistance R ₁₂
And is integrated by the capacitor C _11, a sawtooth wave voltage generated is integrated is input to the base of the transistor Q _6, transistor Q ₆ reaches a predetermined voltage is turned on. Base voltage of the transistor Q ₅ the transistor Q ₆ is turned on is turned off the transistor Q ₅ decreases.

The fourth drive winding W_3dConnected to
Densa C₀The voltage generated at the resistor R _{twenty one}Through the transition
Star Q₇Input to the base of the transistor Q₇But
On. And transistor Q₇From the emitter of
Transistor Q₇A DC voltage that is inversely proportional to the on resistance of
Transistor Q₆Input to the base of. That is,
Transistor Q₆The base voltage of the DC voltage is a sawtooth wave
The voltage becomes a superimposed voltage, and the transistor Q₇Collector of
Transistor Q due to DC voltage₆Turns on
Imming changes.

The first drive winding W_3a, The second drive winding W
_3b, The third drive winding W_3c, 4th drive winding W_3dGenerated in
Pressure is diode D₀The period when the anode of is negative voltage
Capacitor C₀Without charging the battery, the
Densa C₀Charge. Each of the batteries thus charged
Indexer C₀, C₀, C₀The voltage of photo coupler PC1, PC2,
It is supplied to the series connection circuit of the light receiving transistors of PC3 and PC4.
You. Here, the oscillation circuit 4 oscillates and the light emitting diode
When PD1 and PD3 are emitting light, light emitting diodes PD2 and PD
4 does not emit light, and light emitting diodes PD1 and PD3 do not emit light
Light emitting diodes PD2 and PD4
The operation is repeated alternately. As a result, photocouplers PC1 and PC
When 3 is on, bipolar transistor BT₁, BT_Three
Capacitor C on the base of₀The voltage of the
Latransistor BT₁, BT_ThreeTurns on. See also
When the plastic PC2 and PC4 are on, the bipolar transistor B
T _Two, BT_FourCapacitor C on the base of₀Voltage is input
Bipolar transistor BT_Two, BT_FourTurns on
You.

The fourth drive winding W_3dConnected to
Densa C₀Is the power supply voltage input terminal of the power control circuit 2
Input to 2e, power control circuit 2 lights high pressure discharge lamp LP
The power is controlled to be constant. And as mentioned above
Bipolar transistor BT ₁, BT_ThreeTurn on
Between the positive and negative voltage output terminals 2c and 2d of the power control circuit 2.
Voltage is bipolar transistor BT₁, BT_ThreeThrough
Is supplied as a positive voltage to one terminal of the high pressure discharge lamp LP.
Is done. In addition, the bipolar transistor BT_Two, BT_FourBut
By turning on, positive and negative voltage output of the power control circuit 2
The voltage between terminals 2c and 2d is bipolar transistor BT_Two,
BT_FourIs supplied to the one side terminal of the high pressure discharge lamp LP.
Negative voltage is supplied. Repeat this operation alternately
A rectangular wave AC voltage is supplied to the high-pressure discharge lamp LP.

The high-pressure discharge lamp LP is lit by the high-voltage pulse applied to the high-pressure discharge lamp LP and the voltage supplied from the power control circuit 2. When the high-pressure discharge lamp LP is turned on, the high-voltage pulse output from the starter pulse generation circuit 3 disappears, and the high-voltage discharge lamp LP is supplied with stable electric power due to the rectangular wave AC voltage corresponding to the DC voltage supplied from the power control circuit 2. Keeps lighting.

By the way, the terminal voltage of the high pressure discharge lamp LP is
Initially low, node N₁Voltage is low. This voltage
Is the resistance R_{twenty two}, Resistance R_{twenty one}Through transistor Q₇Bee
Input to the transistor, the base current decreases,
TA Q₇Impedance between collector and emitter of
Resistance is node N₁Inversely proportional to the voltage of. And node
N₁Transistor Q when the voltage is low₇ON resistance of
Large, and therefore transistor Q₆The base current of
Transistor Q₆Is turned on late
, And thereby transistor Q_FiveTaimi turns off
Slowing down, transistor Q_FiveIs turned on for a long time
You. Therefore, the input winding W₁The period during which voltage is input to
Longer, first drive winding W_3a, The second drive winding W_3b, Third
Drive winding W_3c, 4th drive winding W_3dOutput voltage rises,
Capacitor C connected to each of those windings₀Voltage is above
Ascend, bipolar transistor BT₁, BT_Two, BT
_Three, BT_FourThe base voltage of the
Ipolar transistor BT ₁, BT_Two, BT_Three, BT_Four
Is driven.

However, the high pressure discharge lamp after the initial lighting
When the lighting of is stable, the terminal voltage of the high pressure discharge lamp LP rises.
As it rises, node N₁Voltage rises.
This voltage is the resistance R_{twenty two}, Resistance R_{twenty one}Through transistor Q
₇Input to the base of the
Transistor Q₇ON resistance of node N₁According to the voltage of
Drop, transistor Q₆The base voltage rises significantly
Becomes, transistor Q ₆The timing to turn on is early
Transistor Q_FiveTurns off earlier
And transistor Q_FiveThe off period becomes longer. I mean
Transistor Q_FiveThe ON period of becomes short. Therefore, enter
Winding W₁The period during which the voltage is input to the
Winding W_3a, The second drive winding W_3b, The third drive winding W_3c, 4th
Drive winding W_3dOutput voltage drops and contacts each of those windings.
Continued capacitor C₀The voltage of the
Langista BT₁, BT_Two, BT_Three, BT_FourAt the base of
Is input a voltage lower than the initial lighting and drives each
Will be.

In this way, the base voltages of the bipolar transistors BT ₁ , BT ₂ , BT ₃ and BT ₄ are controlled according to the terminal voltage of the high pressure discharge lamp LP.
Bipolar transistors BT ₁ , BT ₂ , BT ₃ , BT
_The drive conditions for driving ₄ can always be made appropriate.
Thereby, the bipolar transistors BT ₁ , BT ₂ ,
It is possible to reliably prevent destruction of BT ₃ and BT ₄ due to heat generation or destruction due to an increase in heat loss, and it is possible to light the high-pressure discharge lamp LP using an inexpensive bipolar transistor.

[0046] When the voltage of the AC power supply AC is changed, the DC voltage output from the rectifier bridge 1 also fluctuates, the voltage of the auxiliary winding W ₂ is varied, the voltage variation diode D _1, Zener diode ZD ₂ , resistance R ₁₆
Is input to the base of the transistor Q ₇ via the transistor Q ₆ to change the timing at which the transistor Q ₆ is turned on and off, and the voltage of the capacitor C ₀ is not affected by the voltage fluctuation of the AC power supply AC.

Further, since the Zener diode ZD ₃ and the diode D ₃ are used, when the voltage of the positive voltage output terminal 2c of the power control circuit 2 rises abnormally, the Zener diode ZD ₃ acts to cause the transistor Q to operate. The base current of ₇ does not increase and the voltage of the capacitor C ₀ does not drop below a predetermined value.

[0048]

The numerical values of the circuit elements constituting the high pressure discharge lamp lighting device according to the present invention are as follows. R ₁₀ = 24
0kΩ, R ₁₁ = 560Ω, R ₂₂ = 68kΩ, R ₂₁ = 10kΩ, R
₂₂ = 750Ω, R ₁₆ = 22kΩ, R ₁₅ = 100Ω, R ₁₄ = 10k
Ω, R ₁₂ = 6.8 kΩ, R ₁ , R ₂ , R ₃ , R ₄ = 56 Ω, C
₁₃ = 100 μF, C ₁₂ = 18000 pF, C ₁₁ = 10000 pF, D ₁ = Toshiba Corp. model number IS1553, ZD ₂ = NEC Corporation model number RD4.7EB2, ZD ₃ = NEC Corporation Model number RD6.8EB2, D ₃ = Toshiba Corp. model number IS1555, D
₂ = Sanken Electric Co., Ltd. model number ES1, Q ₅ = Sanken Electric Co., Ltd. model number 2SC4304, Q ₆ = Sanyo Co. model number 2SC3070, a Q ₇ = Sanyo Corp. model number 2SC536.

The number of turns of each winding of the switching transformer T ₂ is as follows: input winding W ₁ = 226 turns, auxiliary winding W ₂
= 7 turns, drive windings W _3a , W _3b , W _3c , W _3d = 18 turns each.

Table 1 shows different terminal voltages of the high pressure discharge lamp LP.
Corresponding to bipolar transistor BT₁, BT_Two, B
T_Three, BT_FourCollector current IC, drive winding W_3a,
W_3b, W _3c, W_3dCapacitor C connected to₀Terminal power
Pressure, bipolar transistor BT ₁, BT_Two, BT_Three,
BT_FourBase current IB and collector current IC and base
The result of measuring the ratio with the current IB is shown.

[0051]

[Table 1]

As is clear from Table 1, the bipolar
Transistor BT₁, BT_Two, BT _Three, BT_FourCollection of
The ratio of the base current IC to the base current IB is from 16.4 to 19.2
Range, bipolar transistor BT₁, BT_Two,
BT_Three, BT_FourMake sure that the drive conditions for are always correct
did it. As a result, the terminal voltage of the high pressure discharge lamp LP changes
However, the bipolar transistor BT₁, BT_Two, B
T_Three, BT_FourThe drive of the
Bipolar transistor instead of the power MOSFET used
It was confirmed that the data can be used.

[0053]

As described in detail above, according to the present invention, the drive voltage of the switch element for supplying the voltage to the high pressure discharge lamp is changed based on the terminal voltage of the high pressure discharge lamp.
The drive conditions of the switch element can always be optimized,
Excess or insufficiency of driving of the switch element does not occur, and it is possible to prevent damage due to heat generation of the switch element and increase in switching loss. Therefore, a bipolar transistor can be used for the switch element, and the cost of the high pressure discharge lamp lighting device can be significantly reduced, and the present invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a half of a circuit diagram showing a configuration of a high pressure discharge lamp lighting device according to the present invention.

FIG. 2 is a half part of a circuit diagram showing a configuration of a high pressure discharge lamp lighting device according to the present invention.

FIG. 3 is a half of a circuit diagram showing a configuration of a conventional high pressure discharge lamp lighting device.

FIG. 4 is a half of a circuit diagram showing a configuration of a conventional high pressure discharge lamp lighting device.

[Explanation of symbols]

1 Rectifier bridge 2 Power control circuit 4 Oscillation circuit LP High voltage discharge lamp T ₂ Switching transformer W ₁ Input winding W ₂ Auxiliary winding W _3a ~ W _3d Drive winding BT ₁ ~ BT ₄ Bipolar transistor PC ₁ ~ PC ₄ Photocoupler Q ₅ , Q ₆ and Q ₇ transistors

Claims (2)

[Claims] 1. A DC voltage obtained by rectifying an AC voltage is configured to be supplied to a high-pressure discharge lamp via a switch element, and a drive voltage generated by the DC voltage is applied to the switch element to switch the switch element. In a high pressure discharge lamp lighting device for lighting the high pressure discharge lamp by driving, a bipolar transistor is used for the switch element, and the driving voltage is changed according to a terminal voltage of the high pressure discharge lamp. A high pressure discharge lamp lighting device characterized by the above. 2. A DC voltage obtained by rectifying an AC voltage is configured to be supplied to a high-pressure discharge lamp via a switch element, and a drive voltage generated by the DC voltage is applied to the switch element to switch the switch element. In a high pressure discharge lamp lighting device for lighting a high pressure discharge lamp by driving, a bipolar transistor is used for the switch element, and a transistor is provided for changing the drive voltage according to a terminal voltage of the high pressure discharge lamp. High pressure discharge lamp lighting device.