JPH06111973A - Electric discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To provide an electric discharge lamp lighting device capable of alarming abnormality of its load while maintaining high circuit efficiency when an electric discharge lamp is removed or the abnormality of the load at the end of its service life. CONSTITUTION:An abnormal time electric power supply circuit 4 is provided to generate smoothed DC voltage by taking out an electric current flowing between a connecting point of diodes D3 and D4 an a primary winding tap of a transformer T3 when a load is abnormal, and a control circuit 2 is arranged to alarm abnormality of the load being energized by this abnormal time electric power supply circuit 4. Since the abnormality of the load is alarmed by using the abnormal time electric power supply circuit 4 to take out abnormal voltage caused in an inverter circuit only when the load is abnormal, it is not necessary to secure wasteful electric power consumption when it is normal, so that circuit efficiency can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device for lighting a discharge lamp by means of a resonance type inverter circuit. More specifically, the discharge lamp is removed or a load abnormality such as end of life occurs. The present invention relates to a protection circuit that operates when

[0002]

2. Description of the Related Art FIG. 11 shows a conventional example (US Pat. No. 4,463).
1 is a circuit diagram of No. 1,980). In this conventional example, the AC power supply AC is full-wave rectified by the diode bridge DB,
The DC power source is smoothed by the capacitor C ₀ . The inverter circuit includes a resonance circuit of an inductor L and a capacitor C, and has a half-bridge circuit configuration with switching elements Qa and Qb and capacitors Cx and Cy. The switching elements Qa and Qb are driven by a self-exciting method in which a resonance current is detected by a transformer Tx and a voltage is alternately generated to drive the switching elements Qa and Qb. The discharge lamp W is connected to both ends of the resonance capacitor C. Also, a resistor Ri and a capacitor C
The starting circuit is composed of i and the trigger element Qc. The inverter circuit oscillates by turning on / off the switching elements Qa and Qb, and the inductor L and the capacitor C
High frequency energy is generated by the resonance circuit including
The discharge lamp W is lit at high frequency. An intermediate tap is provided on the primary winding of the inductor L in the resonance circuit,
Diodes Dx and Dy are connected to the intermediate tap. When the voltage generated in the primary winding of the inductor L becomes larger than the power supply voltage when the discharge lamp W is removed or a load abnormality such as the end of life occurs, the energy of the abnormal voltage is transferred to the diodes Dx and Dy. Return to the power supply side via. At that time, the abnormal voltage of the inductor L is fed back from the center tap of the inductor L to the capacitor C0 on the power supply side through the diodes Dx and Dy through the heater unit H of the vital switch circuit B, and then to the heater unit H of the bimetal switch circuit B. When a current flows, the contact S of the bimetal switch circuit B is turned on. Since the contact S of the bimetal switch circuit B is connected between the control electrodes of the switching element Qb for oscillation, when the contact S of the bimetal switch circuit B is turned on, the oscillation of the inverter circuit is stopped. .

[0003]

In the above-mentioned conventional example, the voltage generated in the primary winding of the inductor L is detected when the discharge lamp W is removed or a load abnormality such as the end of life occurs. , To stop the oscillation of the inverter circuit,
In the above circuit method, the contact S of the bimetal switch circuit B is in a closed state even after the oscillation of the inverter circuit is stopped at the time of abnormality and then returned to the normal state, and it takes time until the contact S is opened. There is a problem of cost. Also,
If the oscillation stop of the inverter circuit suddenly occurs at the end of the life of the discharge lamp W, etc., the circuit operation can be protected, but the user using the lighting equipment cannot know that the discharge lamp W is near the end of the life. Then, the discharge lamp W suddenly goes out, and there is a problem that it is very inconvenient until the discharge lamp W is replaced, for example, when the lighting is absolutely necessary at night. On the other hand, if a circuit is added only at the end of the life and a function such as notifying the life of the discharge lamp W is added, an unnecessary circuit is added during normal operation, and the power consumption of that circuit is secured. However, there is also a drawback that the circuit efficiency is deteriorated due to the necessity of performing

Therefore, in the present invention, the discharge lamp is removed,
When a load abnormality such as the end of life occurs, the circuit for notifying the load abnormality is supplied with power by using the voltage generated at the time of abnormality, and the circuit efficiency can be maintained high by not supplying power during normal operation. An object of the present invention is to provide a discharge lamp lighting device. Another object of the present invention is not to simply stop the oscillation of the inverter circuit at the time of load abnormality, but to suppress the oscillation output while maintaining the optical output that is not inconvenient for the user. An object is to provide an electric lamp lighting device.

[0005]

According to the present invention, in order to solve the above problems, as shown in FIG. 1, a series circuit of first and second switching elements Q ₁ and Q ₂ is connected to a DC power source E ₀ . Are connected in parallel, and the first and second switching elements Q ₁ and Q ₂ are connected in reverse parallel to the first and second diodes D ₁ and D ₂ , respectively, and the first or second switching element Q ₁ or Q 2 is connected. ₂ , a resonance circuit of an inductor L ₁ and a capacitor C ₂ is connected in parallel, and a discharge lamp R ₀ is connected to the secondary winding of a transformer T _{3 having} a primary winding connected in parallel with the inductor L ₁ or the capacitor C _2. And a series circuit of the third and fourth diodes D ₃ and D ₄ is connected in antiparallel to the DC power source E ₀ , and the third and fourth diodes D ₃ and D 4 are connected.
_In the discharge lamp lighting device in which the connection point of ₄ is connected to the tap provided on the primary winding of the transformer T, the connection point of the third and fourth diodes D ₃ and D ₄ and the transformer T are connected when the load is abnormal. Abnormal power supply circuit 4 that takes out the current that flows between the taps of the primary winding of ₃ and generates a smoothed DC voltage
And a control circuit 2 which is energized by the power supply circuit 4 at the time of abnormality to notify the load abnormality.

The DC power source E ₀ may be a power source obtained by rectifying and smoothing an AC power source. Further, the transformer T ₃ may be omitted, and as shown in FIG. 6, the current at the time of load abnormality may be taken out from the tap provided on the resonance inductor L ₁ .
Further, as shown in FIG. 7, the present invention may be applied to a single-stone inverter circuit.

[0007]

According to the present invention, when an abnormal voltage in the resonant circuit to a load abnormality occurs, this voltage diode D _3, D ₄
By being fed back to the DC power source E ₀ via the, and taking out the feedback current, the power source can be supplied only when the load is abnormal. By using this power supply to notify the load abnormality, it is not necessary to secure useless power consumption under normal conditions, and the circuit efficiency can be improved. By notifying the load abnormality by suppressing the oscillation output of the inverter circuit, the stress of the inverter circuit at the time of load abnormality can be reduced, and the minimum necessary light can be secured for the user, so it disappears completely. The degree of inconvenience is less than that in the case.

[0008]

FIG. 1 is a circuit diagram of an embodiment of the present invention. Since
The circuit configuration will be described below. DC power supply E₀To
Is the switching element Q₁, Q₂Series circuit of parallel
It is connected. Each switching element Q₁, Q₂Has
Each diode D₁, D ₂Are connected in anti-parallel
It One switching element Q₁At both ends of the
Capacitor C₁Through the inductor for resonance
L₁And capacitor C₂The series circuit of is connected. Ko
Indexer C₂At both ends of the transformer T₃The primary winding of
Has been continued. Transformer T₃Discharge lamp load on the secondary winding of
R₀Are connected. Capacitor C₂Is the inductor L
₁Together, they form an LC series resonance circuit. Also,
Pulling capacitor C₁Is the capacitor C₂compared to
Has a sufficiently large capacitance that it does not contribute to resonance.

The switching elements Q ₁ and Q ₂ are control circuits 1
Driven by. Further, the DC power source E ₀ in parallel with the diode D _3, which series circuit of D ₄ are connected, the connection point of the diodes D ₃ and D _4, through the primary winding of the transformer T _1, transformer T ₃ Is connected to the center tap of the primary winding of the. In the secondary winding of the transformer T ₁ , a diode D ₅ , a resistor R ₃ , and an electrolytic capacitor C ₃ constitute an abnormal power supply circuit 4, and the abnormal power supply circuit 4 operates the control circuit 2. Is. Although a specific circuit example of the control circuit 2 will be described later, the control circuit 2 performs an operation of suppressing / limiting the light output of the discharge lamp R ₀ and reporting an abnormality.

In this embodiment, the operation of feeding back the abnormal voltage generated in the primary winding of the transformer T ₃ to the DC power source E ₀ by the diodes D ₃ and D ₄ when the load is abnormal will be described. FIG. 2 shows a DC power source E via a diode D ₃ .
₃ shows the flow of the current i ₃ returning to ₀ , and FIG. 3 shows the flow of the current i ₄ returning to the DC power source E ₀ via the diode D ₄ . First, as shown in FIG. 3, when the voltage v ₃ of the illustrated polarity is generated between one end of the primary winding of the transformer T ₃ and the center tap, the inductor L ₁ for resonance is used.
Assuming that the voltage generated at V ₁ is v ₁ + v ₃ > E ₀ , the current i ₃ is fed back to the DC power source E ₀ via the diodes D ₃ and D ₂ as shown in the figure. Flow to. Therefore, the voltage (v ₁ + v ₃ ) does not exceed the power supply voltage E ₀ , and the abnormal voltage is limited. Similarly, as shown in FIG. 3, the abnormal voltage v of the illustrated polarity
_{When 3} is generated and (v ₁ + v ₃ )> E ₀ is attempted to be satisfied similarly to the above, the current i ₄ is supplied to the DC power source E ₀ via the diodes D ₁ and D ₄ . Therefore, the voltage (v ₁
+ V ₃ ) is such that the abnormal voltage is limited without exceeding the power supply voltage E ₀ . The above is the operation of the clamp circuit using the diodes D ₃ and D ₄ .

[0011] Thus, when the abnormal voltage is generated, a current flows through the primary winding of the transformer T _1, since the induced voltage is generated in the secondary winding of the transformer T _1, the voltage diode D _5, the resistor R ₃ The control circuit 2 can be operated by rectifying and smoothing by the capacitor C ₃ to obtain the power supply voltage. That is, since the control circuit 2 is not supplied with the power supply voltage during normal lighting, it does not consume power at all, and the power supply voltage is supplied to the control circuit 2 by supplying unnecessary energy only when an abnormal voltage occurs. Therefore, the circuit efficiency is such that there is no loss during normal operation.

FIG. 4 shows a more specific circuit configuration of the first embodiment of the present invention. In this circuit, the switching elements Q ₁ and Q ₂ are the secondary windings n ₂ and n _{3 of the} resonance transformer T _2.
Driven by the oscillating voltage, and the OFF signal of the switching element Q ₂ is given by the control circuit 1. According to the present embodiment, when the discharge lamp R ₀ is removed or a load abnormality such as the end of life occurs, the power supply circuit 4 at the time of abnormality is used.
Since the control circuit 2 is operated by the power supplied from the control circuit, the constant of the control circuit 1 for controlling the off-timing of the switching element Q ₂ is changed to suppress the oscillation output of the inverter circuit. Compared with the case where the oscillation is stopped, the degree of inconvenience to the user is significantly small, and further, the light output is reduced, so that the user can be notified of the abnormality. Also,
In the circuit that controls the output suppression in such an abnormality, when a load abnormality occurs, the power is supplied by the abnormal voltage, so there is no need to secure unnecessary power consumption in the normal state. The circuit efficiency can be improved.

FIG. 5 shows a concrete circuit structure of the control circuits 1 and 2.
Showing success. Items denoted by reference characters A to H in FIGS.
The stations are connected to each other. In the control circuit 1 of FIG.
Switching element Q output from child A₂Off signal
The transistor Q₃Is controlled by turning on / off the
It Transistor Q₃When the switch turns on, the switching element
Q ₂Turn off. Transistor Q₃ON / OFF is
Computer CP₁Is determined by the comparison operation of
Lator CP₁The potential of the non-inverting input terminal of the
When it is lower than the potential, the comparator CP₁Output is L
It becomes the ow level and the transistor Q₃Turns off. Reverse
And the comparator CP₁The potential of the non-inverting input terminal of is inverted
When the potential is higher than the input terminal potential, the transistor Q₃Is
It turns on. Comparator CP₁Of the non-inverting input terminal of
Pressure is resistance R₇And capacitor C₆Determined by the time constant of
In addition, the voltage at the inverting input terminal is the resistance R_TenAnd R₁₁Partial pressure of
It depends on the ratio. Here, the switching element Q₂Is o
Winding n₃When the induced voltage of
Transformer T₂Winding n_FiveThe induced voltage generated in
Transistor Q_FiveOff, Q_FourIs on, so
Indexer C₆Is not charged, comparator CP₁Output
Also goes low and transistor Q₃Is off
is there. Next, the switching element Q₂Is turned on,
Winding n₃When the induced voltage of
_FiveIs on, transistor Q_FourTurns off. This allows
Capacitor C₆Is resistance R₇It is charged with the charging current determined by
And the charging voltage is the resistance R_Ten, R₁₁Exceeds the voltage determined by
Then, the comparator CP₁Output is high level
Transistor Q₃Is turned on, the switching element
Child Q₂Turns off. That is, the capacitor C₆Charging power
Pressure is comparator CP₁Exceeds the voltage at the inverting input terminal of
Until switching element Q₂Is on, so this
The voltage at the inverting input terminal is the resistance R_TenAnd R₁₁Depending on the partial pressure ratio of
By adjusting, switching element Q₂On width of
It can be set freely. Transformer T₂Winding n_Four
Is for the power supply of the control circuit 1, and the induced voltage is
De D₆And capacitor C_FourRectifying and smoothing by the power circuit
Are configured.

Here, due to the voltage v generated in the primary winding of the transformer T ₃ at the time of load abnormality, the charging voltage is generated in the capacitor C ₃ of the power supply circuit 4 at the time of abnormality by the operation described above.
By applying a High-level voltage signal obtained by dividing by the resistance R _21, R ₂₂ of the control circuit 2 that voltage to the input terminal of the inverting circuit N _1, the output terminal of the inverting circuit N ₁ is Low level (ground potential) And the resistance R ₂₃ is the resistance R of the control circuit 1.
₁₁ connected in parallel. Therefore, the comparator CP
_When the voltage at the inverting input terminal of ₁ decreases and the charging voltage of the capacitor C ₆ is low, the output level of the comparator CP ₁ is inverted and the transistor Q ₃ is turned on, so that the switching element Q ₂ is turned off, and thus switching is performed. Element Q
On-time of ₂ will be shorter. Therefore, when an abnormal voltage occurs, the ON width of the switching element Q ₂ is shortened, the resonance of the inverter circuit is weakened, and the output of the inverter is suppressed.

As described above, in the present embodiment, the output of the inverter circuit at the time of abnormality is lowered and the discharge lamp R ₀ is turned on in the dimming state without being extinguished, thereby avoiding the stress state on the circuit. However, unlike the conventional example, it does not completely stop the oscillation of the inverter circuit. Also,
The control circuit 2 connects the resistor R ₂₃ to the terminal D of the control circuit 1 when an abnormality occurs.
Is connected to the control circuit 2 and the voltage at the terminal D is lowered by resistance voltage division, and the voltage at the terminal E of the control circuit 2 occurs only in the abnormal state.
Does not work at all. By connecting the diode D ₇ as shown in the figure, the control power supplied by the abnormal voltage is supplied to the power supply circuit of the control circuit 1, so that the energy of the abnormal voltage can be used more or less effectively. is there.

In the embodiment of FIG. 1, the output transformer T ₃
An example in which there is no is shown in FIG. Further, FIG. 7 shows an embodiment in which an output circuit T ₃ is not provided and a single-stone inverter circuit is used. These two examples show the inductor L for resonance.
₁ is provided with an intermediate tap to clamp an abnormal voltage exceeding the power supply voltage E ₀ generated in the inductor L ₁ .
Since the clamp operation is the same as the configuration example of FIG. 1, the description thereof will be omitted.

FIG. 8 shows the circuit configuration of the second embodiment of the present invention. In this embodiment, instead of the DC power source E0,
The output voltage of the boost chopper circuit is used as the power source of the inverter circuit. This boost chopper circuit uses AC power supply AC
Is full-wave rectified by the diode bridge DB, and the capacitor C ₀ is charged by the output of the chopper circuit including the inductor L ₀ , the switching element Q ₀ , and the diode D ₀ ,
The boosted DC voltage Vdc is used as the power source of the inverter circuit. This DC voltage Vdc is a voltage boosted higher than the DC voltage obtained by rectifying and smoothing the AC power supply AC. The switching element Q ₀ of the chopper circuit is controlled by the control circuit 3. The power supply of the control circuit 3 is obtained by providing a secondary winding on the inductor L _{0 of the} chopper circuit and rectifying and smoothing the induced voltage by the diode D ₉ , the resistor R ₁₇ , and the capacitor C ₉ . Further, the inverter circuit alternately turns on / off the switching elements Q ₁ and Q ₂ by the induced voltage in the secondary winding provided in the transformer T ₂ for resonance.
It is a self-excited circuit system that turns off.

In this embodiment, an abnormality occurs when the load is abnormal.
When voltage is generated, capacitor C₃The voltage is charged to
Resistance R due to the voltage₁₆Through transistor Q₆Is o
To reduce the power supply voltage of the control circuit 3 and
The operation of the circuit is stopped. For this reason,
Sensor C₀Charges only the voltage obtained by rectifying and smoothing the AC power supply AC
The voltage supplied to the inverter circuit is
Output of the inverter circuit decreases. Also, Inver
Since the power supply voltage of the digital circuit decreases, diode D ₃, D_Four
This increases the current that feeds back the abnormal voltage to the power supply, and
The operation for suppressing the normal voltage is performed.

FIG. 9 shows a circuit configuration of the third embodiment of the present invention.
is doing. In this embodiment, unnecessary power is supplied to the discharge lamp when an abnormality occurs.
It was used for pre-heating the filament during operation. Electric
When the power is turned on, the discharge lamp R₀It takes a short time to start lighting
Becomes a so-called no-load state, and the transformer T₃To the design of
Therefore, the diode D₃, D_FourThrough the tiger
T₁Current flows through the primary winding of the
Su T₁Induced voltage is generated in the secondary winding of the
Light load R₀Apply a preheating current to the filament of the discharge lamp
R₀It makes it easier to light up when starting. Also, during normal lighting
Is the diode D ₃, D_FourNo current flows through
Therefore, almost no current flows through the filament.

FIG. 10 shows the circuit configuration of the fourth embodiment of the present invention. In this circuit, the incandescent lamp Lp is lit by using the power supply circuit 4 at the time of abnormality, and unnecessary energy at the time of load abnormality is converted into light of the incandescent lamp Lp to provide a notification function to inform the abnormality. It is a thing. In the above embodiments, the bipolar transistor is used as the switching element, and the diode is connected in antiparallel between the collector and the emitter, but a power MOSFET may be used as the switching element. In that case, between the drain and the source. Since the anti-parallel diode is parasitic on, it is not necessary to connect the anti-parallel diode to the outside of the switching element.

[0021]

According to the present invention, when the discharge lamp comes off, or when there is a load abnormality such as at the end of life, the load abnormality is notified while the discharge lamp is kept lit, and the circuit for notifying the load abnormality is used when an abnormality occurs. Since it operates by only the power source supplied, there is no need to secure unnecessary power consumption during normal lighting,
There is an effect that a discharge lamp lighting device with good circuit efficiency can be provided.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a circuit diagram for explaining a first operation of the first exemplary embodiment of the present invention.

FIG. 3 is a circuit diagram for explaining a second operation of the first exemplary embodiment of the present invention.

FIG. 4 is a circuit diagram showing a specific configuration of the first exemplary embodiment of the present invention.

FIG. 5 is a circuit diagram of a control circuit used in the first embodiment of the present invention.

FIG. 6 is a circuit diagram showing a modification of the first embodiment of the present invention.

FIG. 7 is a circuit diagram showing another modification of the first embodiment of the present invention.

FIG. 8 is a circuit diagram of a second embodiment of the present invention.

FIG. 9 is a circuit diagram of a third embodiment of the present invention.

FIG. 10 is a circuit diagram of a fourth embodiment of the present invention.

FIG. 11 is a circuit diagram of a conventional example.

[Explanation of symbols]

E ₀ DC power supply R ₀ Discharge lamp load Q ₁ Switching element Q ₂ Switching element D ₁ diode D ₂ diode L ₁ Resonance inductor C ₂ Resonance capacitor D ₃ diode D ₄ diode 4 Abnormal power supply circuit

Claims (3)

[Claims] 1. A direct current power source is connected in parallel with a series circuit of first and second switching elements, and first and second switching elements are connected in reverse parallel with first and second diodes, respectively. A resonance circuit of an inductor and a capacitor is connected in parallel to the second switching element, and a discharge lamp load is connected to the secondary winding of a transformer having a primary winding connected in parallel with the inductor or the capacitor. A discharge lamp lighting device in which a series circuit of a fourth diode is connected in anti-parallel to the DC power source, and a connection point of the third and fourth diodes is connected to a tap provided in the primary winding of the transformer. In the case of abnormal load, the third and fourth
An abnormal power supply circuit that takes out the current flowing between the connection point of the diode and the tap of the primary winding of the transformer and generates a smoothed DC voltage is provided. A discharge lamp lighting device having a circuit for notifying. 2. A direct current power supply is connected in parallel with a series circuit of first and second switching elements, and first and second switching elements are connected in reverse parallel with first and second diodes, respectively. A resonance circuit of an inductor and a capacitor is connected in parallel to the second switching element, a discharge lamp load is connected in parallel to the inductor or the capacitor, and a series circuit of third and fourth diodes is connected to the DC power source in reverse. In a discharge lamp lighting device, which is connected in parallel and a connection point of third and fourth diodes is connected to a tap provided on the inductor, a connection point of the third and fourth diodes and the tap of the inductor when a load is abnormal. An abnormal power supply circuit is provided to take out the current flowing between the two and generate a smoothed DC voltage.The abnormal power supply circuit is energized to report a load abnormality. A discharge lamp lighting device having a circuit for knowing. 3. The discharge lamp lighting device according to claim 1, wherein one of the first and second switching elements is replaced with a resonance circuit composed of an inductor and a capacitor.