JPH10270184A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device where only a small current flows even if an electric shock current flows. SOLUTION: A control circuit 5 is supplied with power through a start-up resistor R1 to turn on a transistor Q1. A current flows through a resonance capacitor C2, a first inductor L1 of a resonance inductance circuit 4, and a primary winding Tr1a of a second inductor L2 and of a transformer Tr1 to induce a voltage in a secondary winding Tr1b of the transformer Tr1. The parallel resonance of the capacitor C2, the first inductor L1, and the primary winding of the second inductor L2 and of the transformer Tr1 induce a high-frequency voltage in the secondary winding Tr1b to effect the high-frequency lighting of a fluorescent lamp FL. When making contact with the fluorescent lamp FL, a potential difference of the secondary winding Tr1b of the inverter transformer Tr1 is lowered to keep a small electric shock current even if the electric shock current flows through a commercial AC power source (e), a full-wave rectification circuit 1, a floating capacity of the inverter transformer Tr1, the fluorescent lamp FL and a human body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp lighting device for lighting a discharge lamp.

[0002]

2. Description of the Related Art Conventionally, as a discharge lamp lighting device of this type, for example, a configuration shown in FIG. 10 is known.

In the discharge lamp lighting device shown in FIG. 10, a full-wave rectifier circuit 1 is connected to a commercial AC power supply e, and an output terminal of the full-wave rectifier circuit 1 is connected to a smoothing capacitor C1.
The inverter circuit 2 is connected to the capacitor C1.

[0004] A parallel resonance circuit 3 is connected to the inverter circuit 2. This parallel resonance circuit 3
A resonance inductance circuit 4 including a first inductor L1, a series circuit of a second inductor L2 and a primary winding Tr1a of a leakage flux type inverter transformer Tr1, and a resonance capacitor C2 which resonates with the resonance inductance circuit 4; And A transistor Q1 as a switching element is connected in series to the parallel resonance circuit 3. Further, a control circuit 5 is connected to the transistor Q1, and the control circuit 5 is magnetically connected to the starting resistor R1 and the inverter transformer Tr1.

[0005] The secondary winding of the inverter transformer Tr1
A load circuit 6 is connected to Tr1b. The load circuit 6 has a fluorescent lamp FL, and a filament FL of the fluorescent lamp FL.
1 and FL2 are connected to one end, and the other end of the filaments FL1 and FL2 is connected to a starting capacitor C3.

When the power is turned on, the starting resistor R1
The control circuit 5 starts the operation through the control circuit 5 and causes the transistor Q1 to perform a high-frequency switching operation by the control circuit 5, and the inverter transformer of the inductance circuit 4
The primary coil Tr1a of Tr1, the first inductor L1 and the second inductor L2 resonate with the capacitor C2, a resonance voltage is generated in the secondary winding Tr1b of the inverter transformer Tr1, and the fluorescent lamp FL is turned on at a high frequency. You. Further, the lighting of the fluorescent lamp FL is stabilized by the current limiting inductance generated by the leakage inductance of the inverter transformer Tr1.

[0007]

However, when the discharge lamp lighting device shown in FIG. 10 touches the fluorescent lamp FL, as shown in FIG. 11, the commercial AC power source e, the full-wave rectifier circuit 1, and the second The electric shock current Ia may flow through the inductor L1, the stray capacitance CTr of the inverter transformer Tr1, the fluorescent lamp FL, and the human body. If the electric shock current Ia flows, the potential difference Va increases due to the second inductor L2. Therefore, there is a problem that the electric shock current Ia may increase as shown in FIG.

The present invention has been made in view of the above problems, and has as its object to provide a discharge lamp lighting device that requires only a small current even if an electric shock current flows.

[0009]

According to a first aspect of the present invention, there is provided a discharge lamp lighting device comprising: a primary winding of an insulation type transformer having a discharge lamp connected to a secondary winding; and a negative potential of the primary winding. A resonance inductance circuit having an inductor connected in series on the side, a resonance capacitor resonating with the resonance inductance circuit, and a switching element located on the minus side of the resonance inductance circuit and generating a high-frequency voltage by a switching operation Is provided. The switching of the switching element is also controlled in accordance with the resonance of the resonance inductance circuit and the resonance capacitor, the discharge lamp is turned on at a high frequency, and even when the discharge lamp is touched, the inductor is located on the minus side of the transformer. The potential generated in the secondary winding of the transformer can be suppressed, the potential difference between the ground does not increase,
Even if an electric shock current flows, the current becomes small.

According to a second aspect of the present invention, there is provided a discharge lamp lighting device, comprising: a first capacitor connected to an AC power supply; a rectifier connected to the first capacitor; and a second capacitor connected to the rectifier. And a partial smoothing circuit having an inductance element and a charging capacitor, connected in parallel to the second capacitor that charges the charging capacitor with a voltage lower than the maximum instantaneous voltage value of the output of the rectifier. A resonance inductance circuit having a primary winding of an insulation type transformer having a discharge lamp connected to a secondary winding side and an inductor connected in series to a negative potential side of the primary winding; A resonance capacitor that resonates, and a high-frequency voltage generated by a switching operation that is located on the minus side of the resonance inductance circuit. Those equipped with an inverter circuit having a switching element. The inverter circuit supplies the input current from the first capacitor and the second capacitor when the output level of the rectifier is equal to or higher than the charge level of the charging capacitor, and the output level of the rectifier is lower than the charge level of the charging capacitor. Sometimes, the input current is supplied from the partial smoothing circuit, the switching element is also switched in accordance with the resonance of the resonance inductance circuit and the resonance capacitor, and the discharge lamp is turned on at a high frequency. Since it is located on the negative side, the potential generated in the secondary winding of the transformer can be suppressed, the potential difference between the grounds does not increase, and even if an electric shock current flows, the current becomes small.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first or second aspect, the resonance inductance circuit includes an inductor in parallel with a series circuit of the primary winding of the transformer and the inductor. It has the same function as the discharge lamp lighting device according to the first or second aspect.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A discharge lamp lighting device according to one embodiment of the present invention will be described below with reference to the drawings. Parts corresponding to those of the conventional example shown in FIG.

In the discharge lamp lighting device shown in FIG. 1, a full-wave rectifier circuit 1 as a rectifier is connected to a commercial AC power supply e, and an output terminal of the full-wave rectifier circuit 1 is connected to a smoothing capacitor C1. The inverter circuit 2 is connected to the capacitor C1.

The parallel resonance circuit 3 is connected to the inverter circuit 2. This parallel resonance circuit 3
A resonance inductance circuit 4 including a first inductor L1, a primary winding Tr1a of a leakage flux type inverter transformer Tr1 and a series circuit of a second inductor L2 on the minus side of the primary winding Tr1a, It has a resonance capacitor C2 that resonates with the circuit 4. A transistor Q1 as a switching element is connected in series to the parallel resonance circuit 3. Further, a control circuit 5 is connected to the transistor Q1, and the control circuit 5 is magnetically connected to the starting resistor R1 and the inverter transformer Tr1.

The secondary winding of the inverter transformer Tr1
A load circuit 6 is connected to Tr1b. The load circuit 6 has a fluorescent lamp FL, and a filament FL of the fluorescent lamp FL.
1 and FL2 are connected to one end, and the other end of the filaments FL1 and FL2 is connected to a starting capacitor C3.

Next, the operation of the above embodiment will be described.

First, a control circuit 5 is connected via a starting resistor R1.
, And the transistor Q1 is turned on. In this way, when the transistor Q1 is turned on, current flows through the resonance capacitor C2, the first inductor L1, the second inductor L2 of the resonance inductance circuit 4, and the primary winding Tr1a of the transformer Tr1, and the Secondary winding Tr1b
, A voltage is induced. Then, the parallel resonance of the capacitor C2, the first inductor L1, the second inductor L2, and the primary winding Tr1a of the transformer Tr1, induces a high-frequency voltage in the secondary winding Tr1b, and the fluorescent lamp FL is lit at a high frequency.

When the fluorescent lamp FL is touched, as shown in FIG. 2, the electric shock current flows through the commercial AC power supply e, the full-wave rectifier circuit 1, the stray capacitance CTr of the inverter transformer Tr1, the fluorescent lamp FL and the human body. Even if Ia flows, the potential difference Va of the secondary winding Tr1b of the inverter transformer Tr1 becomes small, so that the electric shock current Ia can be suppressed as shown in FIG.

Next, another embodiment will be described with reference to FIG.

The embodiment shown in FIG. 4 is obtained by removing the first inductor L1 from the embodiment shown in FIG.

As described above, even if the first inductor L1 is removed, the resonance can be performed by the second inductor L2, so that the operation is the same as that of the embodiment shown in FIG.

Next, another embodiment will be described with reference to FIG.

The embodiment shown in FIG. 5 differs from the embodiment shown in FIG. 1 in that a partial smoothing circuit 7 for valley filling is connected in place of the capacitor C1.

This partial smoothing circuit 7 has a full-wave rectifier circuit 1 having an output terminal connected to a series circuit of a charging capacitor C5, an inductor L5 and a diode D1, a connection point of the inductor L5 and the diode D1, a capacitor C2 and a transistor. The diode D2 is connected between the connection point of Q1.

When the voltage of the full-wave rectifier circuit 1 is higher than the voltage of the charging capacitor C5, power is supplied from the full-wave rectifier circuit 1, and the voltage of the full-wave rectifier circuit 1 is higher than the voltage of the charging capacitor C5. When it is low, power is supplied from the capacitor C5, and the inverter circuit 2 basically operates in the same manner as in FIG.

Another embodiment will be described with reference to FIG.

The embodiment shown in FIG. 6 differs from the embodiment shown in FIG. 5 in that a first capacitor C11 having a relatively large capacity is connected to a commercial AC power supply e via an inductor L6. The input terminal of the full-wave rectifier circuit 1 is connected to the capacitor C11, and the output terminal of the full-wave rectifier circuit 1 is connected to a second capacitor C12 having a smaller capacity than the first capacitor C11.
Are connected.

Next, the operation of the above embodiment will be described.

First, power is supplied to the control circuit 5 via the resistor R1, and the transistor Q1 is turned on.
When the transistor Q1 performs a switching operation and oscillates, a high frequency voltage is generated by the resonance action of the first inductor L1, the second inductor L2, the primary winding Tr1a of the transformer Tr1, the charging capacitor C5, and the resonance capacitor C2. Then, a high-frequency voltage is also induced in the secondary winding Tr1b.

When the transistor Q1 is turned on, the second
Current flows through the inductor L2 and the primary winding Tr1a of the transformer Tr1, and the current flows through the charging capacitor C5, the first inductor L1 and the diode D2, and the charging capacitor C5 is charged. And the charging capacitor
A DC voltage lower than the peak value of the pulsating voltage from the full-wave rectifier circuit 1 can be stored in C5.

Here, a description will be given of a section in which the pulsating voltage of the full-wave rectifier circuit 1 is higher than the charging voltage of the charging capacitor C5 and a section in which the pulsating voltage is lower than the charging voltage.

First, when the transistor Q1 of the inverter circuit 2 is turned on at an arbitrary time in a section where the pulsating voltage of the full-wave rectifier circuit 1 is higher than the charging voltage of the charging capacitor C5, the primary winding Tr1a of the transformer Tr1 is turned on. Most of the current is supplied from the first capacitor C11 and part of the current is supplied from the second capacitor C12, and is charged to the charging capacitor C5. Note that, in a section where the voltage value of the full-wave rectifier circuit 1 is high, the discharge is not performed from the charging capacitor C5 to the inverter circuit 2 side. The combined capacitance of the first capacitor C11 and the second capacitor C12 is sufficient to provide the energy required by the inverter circuit 2. These first capacitor C11 and second capacitor C1
Energy is supplied from the commercial AC power supply e side as an input current and flows in accordance with the current supply from the power supply 2. Then, an operation is performed so as to accompany the switching operation of the transistor Q1 in response to the change of the pulsating voltage, and the small and equal amplitude of the high frequency of the inverter operation of the inverter circuit 2 along the sine wave value of the AC voltage becomes full-wave. The voltage value of the rectifier circuit 1 is superimposed on all high sections.

That is, in the section where the voltage value of the full-wave rectifier circuit 1 is high, the first capacitor C11 and the second capacitor C11
12 is a value in which the energy given by the supplied pulsating voltage is satisfied with respect to the energy required by the inverter circuit 2.

Therefore, the first capacitor C11 and the second capacitor C11
Each of the capacitors C12 has a small ripple component, a small amount of heat generation, and can enhance the operation reliability.

Next, in a section where the voltage value of the full-wave rectifier circuit 1 is low, when the pulsating sine wave voltage of the full-wave rectifier circuit 1 starts to decrease with respect to the charging voltage of the charging capacitor C5, the transistor Q1 is turned on. When turned on, the primary winding Tr of the transformer Tr1
The current to 1a is first supplied from the second capacitor C12, and a current flows through the path of the charging capacitor C5, the inductor L5, the diode D1, and the transistor Q1, and the charging capacitor C5 is charged. DC voltage that is lower than the peak value of the pulsating voltage from. And the second
Since the capacity of the capacitor C12 is not enough to provide the energy required by the inverter circuit 2, the transistor
As the current flowing through the primary winding Tr1a increases after the turning on of Q1, the voltage of the second capacitor C12 decreases. Then, the voltage of the second capacitor C12 is changed to the first capacitor C1.
The first capacitor C11 supplies the energy to the inverter circuit 2 that is insufficient in the second capacitor C12 from the point in time when the voltage drops to 1.

The power is supplied until the transistor Q1 is turned off. However, the decrease in the voltage of the second capacitor C12 after the supply of energy from the first capacitor C11 is started is reduced. In addition, the energy supply from the first capacitor C11 to the inverter circuit 2 causes a corresponding amount of energy to flow as an input current from the commercial AC power supply e side.

On the other hand, the charging voltage of the charging capacitor C5 depends on the first inductor L1, the second inductor L2 and the transformer.
The release of energy is delayed by the transient impedance of the primary winding Tr1a of Tr1, and the energy is released immediately before the transistor Q1 is turned off. Then, when the transistor Q1 is turned off, the charging voltage of the charging capacitor C5 becomes the voltage to the series circuit of the first inductor L1, the second inductor L2, the primary winding Tr1a of the transformer Tr1, the diode D1, and the second capacitor C12. Supply source. Here, the series circuit of the first inductor L1, the second inductor L2, the primary winding Tr1a of the transformer Tr1, and the second capacitor C12 are set so as to obtain an oscillating resonance. Is charged to the capacitor C12 in a sinusoidal waveform. This charging is increased in the inverter circuit 2 to a voltage at which the energy supply does not become insufficient when the transistor Q1 is turned on next time. When the transistor Q1 is turned off, resonance occurs in the capacitor C2 and the series circuit of the first inductor L1, the second inductor L2, and the primary winding Tr1a of the transformer Tr1. This resonance current flows through the path of the diode D1, the diode D2, the primary winding Tr1a of the transformer Tr1, the second capacitor C12, and the capacitor C2, and the second capacitor C12 is charged to generate an oscillating voltage. . At this time, the second capacitor
The voltage at both ends of C12 is almost equal to the DC voltage at both the highest instantaneous voltage portion and the lowest instantaneous voltage portion of the commercial AC power supply e.

Then, as the voltage of the first capacitor C11 decreases with respect to the charging voltage of the charging capacitor C5, the voltage of the second capacitor C12 decreases, and the amplitude due to the first inductor L1 and the second capacitor C12. Becomes larger.
Further, although the input current decreases, the current flows continuously.

As described above, the continuous flow of the input current from the commercial AC power supply e prevents a harmonic component from intervening in the input current.

The operation of the inverter circuit 2 is basically the same as that of the embodiment shown in FIG.

As shown in FIG. 7, a starting capacitor at the other end of the filaments FL1 and FL2 of the fluorescent lamp FL is used.
C13 may be removed so that the filaments FL1 and FL2 are not preheated.

Further, as shown in FIG.
Alternatively, the starting capacitor C3 at the other end of the filaments FL1 and FL2 may be removed, and the starting capacitor C3 may be connected to one end of the filaments FL1 and FL2 so that the filaments FL1 and FL2 are not preheated.

Further, as shown in FIG. 9, one end of each of the filaments FL1 and FL2 of the fluorescent lamp FL is also provided with a capacitor.
C15 may be connected.

[0044]

According to the discharge lamp lighting device of the first aspect, even when the discharge lamp is touched, since the inductor is located on the minus side of the transformer, the potential generated in the secondary winding of the transformer is reduced. It can be suppressed, the potential difference between the grounds does not increase, and even if a lightning current flows, a small current can be obtained.

According to the discharge lamp lighting device of the second aspect,
Even when touching the discharge lamp, the inductor is located on the negative side of the transformer, so the potential generated in the secondary winding of the transformer can be suppressed, the potential difference between the ground does not increase, and the electric shock current flows Even a small current can be generated.

According to the discharge lamp lighting device of the third aspect,
In addition to the discharge lamp lighting device according to the first or second aspect, since an inductor is provided in parallel with the series circuit of the primary winding of the transformer and the inductor, the same effect as the discharge lamp lighting device according to the first or second aspect is obtained. Can play.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is an explanatory diagram showing the same operation.

FIG. 3 is a waveform chart showing the electric shock current.

FIG. 4 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 5 is a circuit diagram showing a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 6 is a circuit diagram showing a discharge lamp lighting device according to still another embodiment of the present invention.

FIG. 7 is a circuit diagram showing a part of a discharge lamp lighting device according to another embodiment.

FIG. 8 is a circuit diagram showing a part of a discharge lamp lighting device according to another embodiment of the present invention.

FIG. 9 is a circuit diagram showing a part of a discharge lamp lighting device according to still another embodiment.

FIG. 10 is a circuit diagram showing a conventional discharge lamp lighting device.

FIG. 11 is an explanatory diagram showing the same operation.

FIG. 12 is a waveform chart showing the electric shock current.

[Explanation of symbols]

 1. Full-wave rectifier circuit as rectifier 2. Inverter circuit 4. Resonance inductance circuit C2 Resonance capacitor C5 Charging capacitor C11 First capacitor C12 Second capacitor e Commercial AC power supply FL Fluorescent lamp as discharge lamp L1, L2 Inductor Q1 Transistor as switching element Tr1 Inverter transformer Tr1a Primary winding Tr1b Secondary winding

Claims (3)

[Claims] 1. A primary winding of an insulation type transformer having a discharge lamp connected to a secondary winding thereof, and a resonance inductance circuit having an inductor connected in series to a negative potential side of the primary winding. A discharge lamp lighting device comprising: a resonance capacitor that resonates with the resonance inductance circuit; and a switching element that is located on the minus side of the resonance inductance circuit and generates a high-frequency voltage by a switching operation. A first capacitor connected to the AC power supply, a rectifier connected to the first capacitor, a second capacitor connected to the rectifier, an inductance element and a charging capacitor. A partial smoothing circuit connected in parallel to the second capacitor for charging the charging capacitor with a voltage lower than the maximum instantaneous voltage value of the output of the rectifier, and a discharge lamp on the secondary winding side Is connected to a primary winding of an insulation type transformer and an inductor connected in series on the negative potential side of the primary winding, a resonance capacitor that resonates with the resonance inductance circuit, and A switching element that is located on the minus side of the resonance inductance circuit and generates a high-frequency voltage by switching operation. The discharge lamp lighting apparatus characterized by comprising a converter circuit. 3. The resonance inductance circuit has an inductor in parallel with a series circuit of a primary winding of the transformer and the inductor.
The discharge lamp lighting device as described in the above.