JP2001155883A - Power supply device, discharge lamp apparatus and bulb type fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp using small size and inexpensive power device that obtains half bridge type of inverter driving signal from feedback circuit of which current of load circuit is improved. SOLUTION: The power device comprises a load circuit having resonance inductance and resonance capacitance operated high frequency alternate current generated at two alternating switches of a first and a second and a second switching means, an unsaturation type of transformer NST in which current proportional to current of the load circuit is excited to a secondary coil, a resonance circuit DRC formed with inductance and capacitance a secondary coil of the unsaturation type of transformer, and a circuit alternatively driving the first and the second switching means with resonance output. When an inductance of a primary coil is Ln1, that of the secondary coil is Ln2, and equal value inductance being series to the secondary coil in short of the primary coil is Ln2δ, these relations is as follows: 100<=Ln2/Ln1, 0.5<=Ln2δ/Ln2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device having a half-bridge type inverter, a discharge lamp device using the same, and a bulb-type fluorescent lamp.

[0002]

2. Description of the Related Art In a discharge lamp lighting device provided with a half-bridge type inverter, a feedback voltage generated in a winding magnetically coupled to a current-limiting inductor of a load circuit is applied to at least one LC parallel oscillation circuit. Japanese Patent Laid-Open No. Hei 9-190891 discloses a self-oscillation type configuration in which a drive signal for alternately driving a pair of switching elements is obtained.

That is, FIG. 1 of the related art shows a load circuit having at least one inductance L2 and at least one capacitor C7, C8, C9,
A lamp lighting circuit device comprising an inverter, which can be formed as a half-bridge device having two switching elements T1, T2, and a driving circuit AS for driving the switching elements, wherein the driving circuit AS comprises: 2 provided for each switching element T1, T2
Circuit part AS1, including two circuit parts AS1, AS2
Are the auxiliary winding HW1 and the LC parallel oscillation circuits L3, C3
The circuit configuration in which the circuit portion AS2 includes an auxiliary winding HW2 and LC parallel oscillation circuits L4 and C4, and each of the auxiliary windings HW1 and HW2 is magnetically coupled to an inductance L2 of a load circuit is disclosed. Have been. (Prior Art 1) FIG. 3 of the above document shows at least one inductance L2 and at least one capacitor C7, C7.
8, a lighting circuit device for a lamp comprising a load circuit having C9, an inverter which can be formed as a half-bridge device having two switching elements T1, T2, and a driving circuit AS for driving the switching elements. The driving circuit AS includes an auxiliary winding HW1 magnetically coupled to the inductance L2 of the load circuit, and an LC that resonates with a feedback voltage induced in the auxiliary winding HW1 to form a driving signal.
A circuit configuration including parallel oscillation circuits L3 and C3 and a transformer TR that inverts and supplies a drive signal to the other switching element T2 is described. (Prior art 2) Further, Japanese Patent Laid-Open No. 10-162983, a half-bridge with a resonant load circuit 16 including a resonant inductor _{L R} and a resonant capacitance _{C R,} the two switches Q1, Q2 of complementary Gate drive circuit 30 of the inverter
A driving inductor L _D which is mutually coupled to the resonant inductor L _R of the resonant load circuit 16, a second inductor 32 connected in series to the driving inductor LD, complementary switches Q1,
The bidirectional voltage clamp 36 for clamping and limiting the gate voltage of Q2 includes a circuit configuration that allows a single gate drive circuit 30 to act commonly on the complementary switches Q1 and Q2. ing. (Prior art 3) Then, in the above-mentioned prior arts 1 to 3, the feedback for driving the switching element is a current-limiting inductance L2 (or a resonance inductor LR).
This is performed by magnetically coupling the auxiliary winding WH1 or WH2 (or the driving inductor LD).

On the other hand, conventionally, a circuit configuration in which a primary winding of a saturable current transformer is inserted in series with a load circuit, a feedback voltage is obtained from the secondary winding, and a drive signal for a switching element is formed. Is also known. (Prior art 4)

However, the prior art 1
In the cases of (3) to (3), a gap is generally provided in the magnetic circuit of the current-limiting inductance (inductor), and therefore, a position where the auxiliary winding WH1 or WH2 for feedback (or the driving inductor L _D ) is wound. (E.g., void or void-free areas), the properties of which vary, requiring fine-grained control during their manufacture,
Eventually, costs will increase.

Since a high voltage is applied to the current-limiting inductance (inductor) by resonance, a high dielectric strength is added to the feedback auxiliary winding WH1 or WH2 (or the driving inductor L _D ) to increase the voltage. Need to give reliability. For this reason, these winding components are increased in size and cost.

Next, in the prior art 4, since a ring core is used for the supersaturated current transformer in order to provide supersaturation characteristics, it is extremely difficult to wind the windings and the characteristics vary greatly. In addition, the difficulty of the design is high,
In addition to the increase in cost, there is a problem that the size of the winding component increases.

The present invention comprises a small and low cost feedback circuit having an improved feedback circuit for the current flowing in the load circuit, wherein the drive signal for the switching means of the half-bridge inverter is derived from the feedback circuit. An object of the present invention is to provide a power supply device, a discharge lamp device using the same, and a bulb-type fluorescent lamp.

[0008]

According to a first aspect of the present invention, there is provided a power supply apparatus comprising: a DC power supply; first switching means and second switching means connected in series between the DC power supplies; A load circuit having capacitance and operated by high-frequency alternating current generated by alternate switching of the first and second switching means; 1
An unsaturated transformer in which a secondary winding is connected to the load circuit and a voltage proportional to the current flowing in the load circuit is induced in the secondary winding;
A drive resonance circuit formed by the capacitance and the inductance of the secondary winding of the unsaturated transformer; and a drive circuit that alternately drives the first and second switching means by a resonance output of the drive resonance circuit. It is characterized by having.

In the present invention and the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

<Regarding DC Power Supply> The DC power supply may be either a rectified DC power supply in which AC is rectified or a battery power supply. In the case of a rectified DC power supply, it is desirable to have a smoothing means. As the smoothing means, a configuration in which a smoothing capacitor or an active filter is connected between the DC output terminals of the rectifier circuit, an active filter configured using first and second switching means to be described later, such as a partial smoothing circuit, etc. May be used, which is a half-bridge type inverter provided with.

<Regarding First and Second Switching Means> The first and second switching means are a pair of switching means for alternately turning on and off a half-bridge type inverter, and have the same polarity and complementary switching elements. Either may be used. Further, either voltage-driven switching means such as a MOSFET or current-driven switching means such as a bipolar transistor may be used.

Since the FET is a voltage drive type switching means, the drive is easy. Also, MOS
The FET is effective as a power switching means that is less restricted by a safe operation area. Further, the enhancement type MOSFET is easy as power-on processing, and is suitable as a power switching means. Furthermore, N-channel MOSFETs are advantageous because the current product lineup is abundant. However, a P-channel MOSFET can be used if desired.

By the way, the switching means is allowed to have a drive terminal. The drive is turned on when a drive signal of a predetermined polarity is supplied to the drive terminal. Enhancement type MOS
In a FET, when a gate voltage as a drive signal is applied between a gate as a drive terminal and a source, a channel is formed and the FET is turned on. Therefore, the off state is maintained when no gate voltage is applied.

"The first and second switching means are connected in series between the DC power supplies" means that the first and second switching means are in a series connection relationship as viewed from the DC power supply. Other circuit components such as inductors and resistors may be interposed between the first and second switching means and the DC power supply. Further, a circuit component may be interposed between the first and second switching means.

<Regarding the Load Circuit> The load circuit has at least a resonance inductance and a resonance capacitance. And it operates by the alternating current generated by the alternating switching of the first and second switching means. The load is connected to an appropriate point in the load circuit.

The resonance inductance and the resonance capacitance can resonate with the alternating current generated by the alternate switching of the first and second switching means. The resonance inductance and the resonance capacitance are at least 1 each.
Are connected to the load circuit, and if necessary, one or both of them can be constituted by a plurality.

When the load has a negative characteristic such as a discharge lamp, one of the resonance inductance and the resonance capacitance is used to act as a current-limiting impedance to compensate for the negative characteristic of the load. Can be configured.

<Regarding the Unsaturated Transformer> The unsaturated transformer has at least a primary winding and a secondary winding, and has a voltage proportional to the current flowing through the load circuit for driving the switching means. Acts on the secondary winding. Therefore, the number of turns on the primary winding side is relatively small, so that the inductance of the primary winding is small and does not substantially contribute as resonance inductance.

The "unsaturated transformer" has a core configured to be substantially free from magnetic saturation or is formed without using a core. Further, "configured so that the core is not saturated" means that the core has a substantially infinite gap length, such as a drum core or a rod core.

Next, the secondary winding of the unsaturated transformer forms a drive resonance circuit, which will be described later, to form a drive signal for the switching means based on the induced voltage.

Further, the unsaturated transformer used in the present invention can be constituted by winding a primary winding on a choke coil having a drum core or a rod core, if necessary. However, not only is the primary winding wrapped over the secondary winding,
It goes without saying that the next winding may be wrapped. Furthermore, the primary winding and the secondary winding of the unsaturated transformer may be wound not only in a lap winding but also adjacently. In this case, a winding frame can be used. Furthermore, the secondary winding may be single or multiple. For example, one secondary winding may be assigned to each of the first and second switching means to provide a drive resonance circuit and a drive circuit. However, even when a pair of secondary windings is provided, if a drive resonance circuit is formed by connecting a capacitance only to one of the secondary windings, the other secondary winding can be formed. Since this also induces a resonance output, there is no need to provide two drive resonance circuits.

<Drive Resonance Circuit> The drive resonance circuit is composed of an inductance and a capacitance as viewed from the secondary winding side of the unsaturated transformer. The resonance circuit in this case may be either a parallel resonance circuit or a series resonance circuit.

Next, the capacitance is determined by using a capacitor or the capacitance of the switching means, eg, MO
The capacitance between the gate and the source of the SFET can be used.

Thus, the drive resonance circuit generates a resonance output having positive and negative polarities by resonance, and supplies the resonance output to a drive circuit described later.

<Regarding the Drive Circuit> The drive circuit is a circuit for forming a drive signal to be supplied to the switching means.

When the pair of switching means have the same polarity, the switching means are turned on and off alternately when the resonance output of the drive resonance circuit is supplied to one switching means with a certain polarity. The other switching means may be supplied with the polarity inverted. For this purpose, for example, the polarity can be easily inverted by using a transformer.

When the pair of switching means has a complementary relationship, the resonance output of the drive resonance circuit can be supplied to both switching means without reversing the polarity.

Next, when the switching means is a voltage drive type, the drive circuit configures the drive circuit to supply a drive voltage. In the case of a current drive type, the drive circuit is configured to supply a drive current.

Further, in the case of using a voltage drive type switching means, if necessary, a voltage clamp circuit can be added to the drive circuit as a gate protection circuit in order to regulate the drive signal to a predetermined voltage. The gate protection circuit prevents an excessive voltage from being applied to the drive terminals of the first and second switching means, and may have any specific circuit configuration.

For example, at least two or more Zener diodes can be connected in series with opposite polarities to form a gate protection circuit. This gate protection circuit can perform a protection function with respect to the positive and negative bipolar resonance voltages.

When the complementary switching means is used, one gate protection circuit exerts a gate protection action on both the first and second switching means.

Further, the gate protection circuit can be configured by various similar circuit configurations as long as it is not a Zener diode as long as it is a constant voltage element.

Further, the number of constant voltage elements to be used may be determined according to the relation between the constant voltage and the gate voltage.

[0034] Then, the voltage that becomes overvoltage with respect to the gate is short-circuited and absorbed by the gate protection circuit, so that only an appropriate voltage is applied to each gate of the first and second switching means. Not done. When an overvoltage is applied to the switching means, the switching means may be destroyed. Therefore, it is preferable to add a gate protection means.

<Other Configurations> In order to start the half-bridge type inverter, a suitable starting circuit can be added. For example, a DC power supply voltage dividing circuit mainly composed of a resistor is configured to divide the DC power supply voltage into a drive terminal of a first switching means for conducting a current from the DC power supply and supply a predetermined start drive signal. Can be done. Further, a circuit mainly including a time constant circuit and a trigger element may be configured so that a predetermined drive signal is supplied from a DC power supply to a drive terminal of the first switching means.

When a rectified DC power supply is used as the DC power supply, a noise filter is provided between the low-frequency AC power supply and the AC input of the rectifier circuit so that high-frequency noise due to switching of the first and second switching means does not flow into the low-frequency AC power supply. It can be inserted between the ends.

<Function of the Present Invention> In the present invention, the load circuit operates by the high-frequency alternating current generated by the alternating switching of the first and second switching means, and the load circuit has a resonance inductance and a resonance capacitance. Since they are provided, they resonate and a sine wave or a current relatively close to the sine wave flows through the load circuit.

When the current flowing in the load circuit flows through the primary winding of the unsaturated transformer, a voltage proportional to the current flowing in the load circuit is induced in the secondary winding.

The drive resonance circuit includes the unsaturated transformer 2
Resonates at the fundamental frequency of the voltage induced in the next winding.

The drive circuit receives the supply of the resonance output of the drive resonance circuit, forms a drive signal, and supplies the drive signal to each switching means.

As a result, the pair of switching means alternately switches on and off, operates as a half-bridge inverter, and generates a high-frequency alternating current.

In the above circuit operation, since the primary winding of the unsaturated transformer is provided separately from the resonance inductance, a high voltage due to resonance of the load circuit is not applied. Therefore, high reliability can be obtained without imparting exceptionally high dielectric strength to the unsaturated transformer.

Also, unlike a supersaturated current transformer in which it is difficult to form a winding, the formation of a winding is easy in the unsaturated transformer, so that the cost can be reduced and the variation in characteristics is small. And design is relatively easy.

Further, the size of the unsaturated transformer can be reduced as compared with that of the supersaturated current transformer.

According to a second aspect of the present invention, there is provided the power supply unit according to the first aspect, wherein the primary winding of the unsaturated transformer is so small as to be negligible as compared with the resonance inductance of the load circuit. It is characterized by having an inductance.

The primary winding of the unsaturated transformer according to the present invention has a small inductance and is configured not to substantially contribute as a resonance inductance, and is arranged separately from the resonance inductance of the load circuit. Has been established. Note that "negligible" means that the inductance is 2% or less, preferably 1% or less, of the resonance inductance of the load circuit.

However, in mounting the circuit, it is desirable to dispose the unsaturated transformer at a distance from the resonance inductance so as not to be affected by the resonance inductance of the load circuit. Also, in this case, since another circuit component such as a capacitor is interposed between the unsaturated transformer and the resonance inductance, a kind of shielding effect is generated, which is more effective in suppressing interference by the resonance inductance. is there.

Thus, in the present invention, since the unsaturated transformer is configured as described above, unlike the resonance voltage of the load circuit, the voltage proportional to the current flowing through the load circuit is changed to the secondary voltage. Can be induced in the winding.

According to a third aspect of the present invention, there is provided the power supply unit according to the second aspect, wherein the unsaturated transformer has a ratio Ln2 / Ln1 of the inductance Ln2 of the secondary winding to the inductance Ln1 of the primary winding. Is 100 or more.

Thus, according to the present invention, the primary winding does not contribute to the resonance inductance of the load circuit by the above configuration, so that a voltage proportional to the current flowing through the load circuit is induced in the secondary winding. And a drive resonance circuit that resonates the inductance Ln2 of the secondary winding with the capacitance to obtain a resonance output required to form a drive signal.

Therefore, the inductance L of the primary winding
ratio Ln2 / L of the inductance Ln2 of the secondary winding to n1
If n1 is less than 100, the inductance L of the primary winding
Since n1 is relatively large, in such a case, the inductance Ln1 of the primary winding starts to contribute as a resonance inductance. Therefore, a voltage proportional to the current flowing through the load circuit is applied to the secondary winding. Can not be induced.
Alternatively, since the inductance Ln2 of the secondary winding is small, the inductance required by the drive resonance circuit cannot be provided.

Therefore, the inductance Ln2 of the secondary winding with respect to the inductance Ln1 of the primary winding of the unsaturated transformer is obtained.
The ratio Ln2 / Ln1 needs to be 100 or more, more preferably 300 to, more preferably 500 to 1.
A range of 000 is good.

According to a fourth aspect of the present invention, there is provided the power supply unit according to the second or third aspect, wherein the unsaturated transformer is connected to the secondary winding when the primary winding is short-circuited with respect to the inductance Ln2 of the secondary winding. The ratio Ln2δ / Ln2 of the equivalent inductance Ln2δ existing in series with the next winding is 0.5 or more.

When the primary winding of the unsaturated transformer is short-circuited, the equivalent inductance Ln2δ existing in series with the secondary winding
Indicates an inductance that contributes to forming a drive resonance circuit together with the capacitance.

In the present invention, the magnitude of the equivalent inductance Ln2δ is defined by the ratio Ln2δ / Ln2 to the inductance Ln2 of the secondary winding. Further, by providing the configuration of the present invention, a drive resonance circuit having a resonance frequency suitable for generating a high-frequency alternating current can be formed.

According to a fifth aspect of the present invention, in the power supply device according to any one of the first to fourth aspects, the first and second switching means are constituted by complementary MOSFETs. And

Since the MOSFET is a voltage drive type switching means, power consumption for driving is small and high speed switching is possible.
It is a switching means suitable for a power supply device that generates high-frequency AC.

The MOSFET may be either an enhancement type MOSFET or a depletion type MOSFET.

Further, the first and second switching means include a complementary type, that is, an N-channel type MOSFET and a P-type MOSFET.
Because it is combined with a channel type MOSFET,
A single drive circuit may be used. That is, when an AC drive voltage is supplied from the drive circuit to the gate and source of each MOSFET simultaneously and in parallel, the N-channel MOSFET turns on when a positive drive signal is applied to its gate. P-channel type MOSFE
T turns on when a negative drive signal is applied to its gate. Therefore, N-channel type MOSF
The ET and the P-channel MOSFET are turned on alternately,
Turn off.

Thus, in the present invention, since the first and second switching means are constituted by complementary MOSFETs, the drive circuit is simplified, so that the size and cost can be reduced. It is effective.

According to a sixth aspect of the present invention, in the power supply device according to any one of the first to fifth aspects, the first and second switching means comprise MOSFETs;
The LC series resonance circuit is characterized in that the capacitor is constituted by the gate-source capacitance of the first switching means.

The FET is known to have a relatively large capacitance between the gate and the source and between the gate and the drain. However, in the present invention, the capacitance between the gate and the source is determined by the drive resonance circuit. Used as capacitance. Therefore, apparently, since no capacitor is connected to the secondary winding of the unsaturated transformer, it does not appear that a drive resonance circuit is formed. However, when the configuration of the present invention is provided, a resonance voltage appears between the gate and the source, so that it can be identified.

Thus, in the present invention, since the capacitance between the gate and the source of the MOSFET is used for the capacitance of the drive resonance circuit, the number of circuit components is reduced, the circuit configuration is simplified, and the size is reduced. And contribute to cost reduction.

According to a seventh aspect of the present invention, in the power supply device according to any one of the first to sixth aspects, the drive resonance circuit includes an inductance and a capacitance of a secondary winding of the unsaturated transformer. Constitute a series resonance circuit.

The present invention defines a preferred configuration of the drive resonance circuit.

That is, the unsaturated transformer has an equivalent inductance when the primary winding is short-circuited by increasing the inductance of the secondary winding and reducing the electromagnetic coupling with the primary winding. Is increased, and this is connected in series with the capacitance to form a series resonance circuit.

Therefore, the drive signal can be generated by the drive circuit in response to the resonance output of the series resonance circuit and supplied to the switching means.

An eighth aspect of the present invention is directed to a discharge lamp device, comprising: the power supply device according to any one of the first to seventh aspects; and a discharge lamp connected to a load circuit.

In the present invention, the discharge lamp may be either a low-pressure discharge lamp or a high-pressure discharge lamp.

The low-pressure discharge lamp is a discharge lamp that utilizes the discharge of low-pressure metal vapor or gas. The low-pressure discharge lamp uses a filament electrode like a fluorescent lamp, and operates the discharge lamp by using the filament electrode as a hot cathode. When starting, the filament electrode is heated at the start,
There are the following two methods.

First, at startup, a resonance capacitance is connected in parallel with the discharge lamp via at least one filament electrode. Then, a current flows to the filament electrode via the resonance inductance and the resonance capacitance at the time of starting, so that the filament electrode is heated. At the same time, the resonance inductance and the resonance capacitance appropriately resonate in series, and the voltage between both ends of the resonance capacitance increases, so that the starting of the discharge lamp is promoted.

The second is to heat the filament electrode using a filament heating transformer. The filament heating transformer may be provided separately from the resonance inductance, but if necessary, the filament heating winding can be magnetically coupled to the resonance inductance. that way,
An increase in the number of circuit components can be suppressed.

Further, in any of the above-described heating methods of the two filament electrodes, not only both of the pair of filament electrodes but also one of the filament electrodes may be heated. This allows
By reducing the filament heating power, the power consumption can be reduced accordingly.

Further, an instant start in which the discharge lamp is started by applying a high voltage between a pair of electrodes without preheating the discharge lamp may be performed.

According to a ninth aspect of the present invention, there is provided a bulb-shaped discharge lamp comprising: a bulb-shaped discharge lamp main body; and the discharge lamp device according to the eighth aspect supported by the bulb-shaped discharge lamp main body. I have.

In the present invention, the term “bulb-shaped discharge lamp” means that the discharge lamp is integrated with its lighting circuit, ie, a ballast, and further provided with a base, which is mounted on a lamp socket adapted to the base. Means a lighting device configured to be used as if lighting an incandescent light bulb.

The discharge lamp may be a low-pressure discharge lamp such as a fluorescent lamp or a high-pressure discharge lamp such as a metal halide lamp.

Further, the “bulb-shaped discharge lamp body”
It refers to the remaining portion of the bulb-shaped discharge lamp excluding the discharge lamp device.

Furthermore, it is permissible to have a glove surrounding the discharge lamp. The glove may have both transparent and light diffusing optical properties. Further, the glove may be transparent or may have been subjected to a surface treatment such as transparent and prism cut.

However, if necessary, the discharge lamp may be directly exposed to the outside without using gloves.

Furthermore, the lighting circuit can be housed in a container-like base, and a base can be provided at an end of the base.

Further, a reflecting mirror for controlling light emission of the discharge lamp may be integrally provided.

Further, the discharge lamp and the lighting circuit are:
At the time of lighting, if it is used in a state of being integrally connected, it may be separable.

Thus, according to the present invention, the size of the discharge lamp device can be remarkably reduced, so that a compact bulb-type discharge lamp can be provided.

[0085]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a conceptual sectional view of the unsaturated transformer.

In each figure, AS is a low-frequency AC power source, f
Is an overcurrent fuse, NF is a noise filter, RD is a rectified DC power supply, Q1 is first switching means, Q2 is second switching means, LC is a load circuit, NST is an unsaturated transformer, and DRC is drive resonance. Circuit, DC is a drive circuit, and ST is a start circuit.

<Regarding Low Frequency AC Power Supply AS> The low frequency AC power supply AS is a commercial 100 V AC power supply.

<Regarding Overcurrent Fuse f> The overcurrent fuse f is formed by a pattern fuse integrally formed on a wiring board on which circuit components of a power supply device and a discharge lamp lighting device are mounted. Protects the circuit from being burned out when burned.

<Regarding Noise Filter NF> The noise filter NF includes a first portion interposed in series between the low-frequency AC power supply AS and the rectified DC power supply RD, and a rectified DC power supply RD and a first switching It is divided into a second portion interposed in series between the means Q1. Then, the high frequency noise generated by the alternate switching of the first and second switching means Q1 and Q2 is prevented from flowing out to the low frequency AC power supply AS.

The first part of the noise filter NF is a capacitor C connected in parallel between the low-frequency AC power supply lines.
1 and surge absorber SA.

The second part is composed of the inductor L1.

<Regarding the Rectified DC Power Supply RD> The rectified DC power supply RD includes a bridge type full-wave rectifier circuit BRC and a smoothing capacitor C2.

The bridge type full-wave rectifier circuit BRC has an AC input terminal connected to the low-frequency AC power supply AS and a DC output terminal connected to both ends of the smoothing capacitor C2.

The smoothing capacitor C2 includes a noise filter N
F is connected between the DC output terminals of the bridge-type full-wave rectifier circuit BRC via an inductor L1 which is a second part.

<First and Second Switching Means Q
1. Regarding Q2> The first switching means Q1 is composed of an enhancement-type N-channel MOSFET, the drain of which is connected to the positive electrode of the rectified DC power supply RD.

The second switching means Q2 also comprises an enhancement-type P-channel MOSFET, the source of which is connected to the source of the first switching means Q1, and the drain of which is connected to the negative electrode of the rectified DC power supply RD. ing. That is, the first and second switching means Q1, Q2 are complementarily connected to the rectified DC power supply RD.

Thus, the first and second switching means Q1 and Q2 constitute a half-bridge type inverter switching circuit, and turn on and off alternately to generate a high-frequency alternating current.

<About Load Circuit LC> Load Circuit LC
Is the resonance inductance L2 and the DC cut capacitor C
A discharge lamp is connected as a load DL to a series circuit including the resonance capacitor 3 and the resonance capacitor C4. The DC cut capacitor C3 and the resonance capacitor C4 constitute the resonance capacitance according to the present invention. However, since the DC cut capacitor C3 has a relatively large capacitance, the resonance capacitor C4 acts dominantly as the resonance capacitance.

The resonance inductance L2 has one end connected to one end of the primary winding p of the unsaturated transformer NST, the other end connected to one end of the DC cut capacitor C3, and constitutes a load DL. Provides a current limiting impedance to the discharge lamp.

The other end of the DC cut capacitor C3 is connected to one end of the discharge lamp DL.

In the present embodiment, a fluorescent lamp is used as a discharge lamp constituting the load DL. The power supply terminal of one filament electrode E1 of the discharge lamp as the load DL is connected to the other end of the DC cut capacitor C3, and the power supply terminal of the other filament electrode E2 is connected to the drain of the second switching means Q2. Connected to

The resonance capacitor C4 is connected between the power supply terminal of one filament electrode E1 of the discharge lamp DL and the non-power supply terminal of the other filament electrode E2. The non-power supply side terminal of the other filament electrode E2 is
It is open.

Thus, the load circuit LC forms a series resonance circuit including the resonance inductance L2, the DC cut capacitor C3, and the resonance capacitor C4.

<Regarding the Unsaturated Transformer NST> The unsaturated transformer NST includes a core CO, a secondary winding s, and a primary winding p.

As shown in FIG. 2, the core CO is formed of a drum-shaped ferrite core, and does not saturate because the magnetic path is open.

The secondary winding s is formed by winding an insulated conductor wire on a core CO for 270 turns. One end is connected to the sources of the first and second switching means Q1, Q2. The inductance Ln2 of the secondary winding s was 1857 μH. Further, when the primary winding p was short-circuited, the equivalent inductance Ln2δ existing in series equivalently to the secondary winding s was 1855 μH.

The primary winding p is formed by winding an insulated conductor 10 turns on the secondary winding s. One end is connected to one end of the secondary winding s, that is, the sources of the first and second switching means Q1, Q2, and the other end is connected to one end of the resonance inductance L1. Therefore, 1
The secondary winding p is inserted in series with the load circuit LC. The inductance Ln1 of the primary winding p is 2.1 μH, and the equivalent inductance Ln1δ existing in series equivalently to the primary winding p when the secondary winding s is short-circuited is 1.2 μH.
H.

Therefore, the ratio Ln2 of the inductance Ln2 of the secondary winding s to the inductance Ln1 of the primary winding p
/ Ln1 is 884.

The ratio Ln2δ / Ln2 of the equivalent inductance Ln2δ to the inductance Ln2 of the secondary winding is about 1.

The above inductances are values measured at a frequency of 1 kHz and a voltage of 1 V.

<Regarding the Drive Resonance Circuit DRC> The drive resonance circuit DRC is configured by connecting the secondary winding s of the unsaturated transformer NST and the capacitor C5 in parallel.
This is a series resonance circuit formed by the inductance Ln2 of the secondary winding s and the capacitance of the capacitor C5. Because
Although the secondary winding s of the unsaturated transformer NST and the capacitor C5 are connected in parallel, if the induced voltage of the secondary winding s is viewed as a power source, the equivalent inductance Ln2δ of the secondary winding s, the capacitor C5 and Are in a series relationship, and they act as a series resonance circuit.

<Regarding Drive Circuit DC> The drive circuit DC includes a capacitor C6 and a gate protection circuit GP.

The capacitor C6 has a relatively large capacitance, and one end has a secondary winding s of the drive resonance circuit DRC.
And the connection point of the capacitor C5 and the gates of the first and second switching means Q1 and Q2.

The gate protection circuit GP is composed of an inverse series circuit of a pair of Zener diodes ZD1 and ZD2, and is connected between the gates of the first and second switching means Q1 and Q2.

<About starting circuit ST> Starting circuit ST
Consists of resistors R1, R2 and R3.

The resistor R1 has one end connected to the positive electrode of the rectified DC power supply RD and the other end connected to the first switching means Q.
1 and the connection point of the capacitor C6 of the drive circuit DC.

The resistor R2 is connected in parallel with the capacitor C6.

The resistor R3 is connected to the second switching means Q
2 are connected in parallel between the drain and source. In addition,
A capacitor C7 is connected in parallel with the resistor R3.

Therefore, resistors R1, R2 and R3
Are connected in series to the rectified DC power supply RD.

<Circuit Operation> Low-frequency AC power supply AS
Is turned on, a DC voltage smoothed by the rectified DC power supply RD appears at both ends of the smoothing capacitor C2. Then, a DC voltage is applied between the drain and the source of the first and second switching means Q1 and Q2 connected in series. However, the first and second switching means Q1,
Q2 remains off because no gate voltage is applied.

The DC voltage of the rectified DC power supply RD is
At the same time, the voltage is applied to the series circuit of the resistors R1, R2 and R3, and a voltage drop corresponding to each resistance value is generated. As a result, the voltage drop of the resistor R2 causes the capacitor C6
Is charged, and the first and second switching means Q1, Q1 are connected via the primary winding p of the unsaturated transformer NST.
Applied between the gate and source of Q2.

The first switching means Q1 includes a resistor R
Since a voltage drop of 2 is applied in the forward direction, a channel is formed and turned on. At this time, the charge of the capacitor C6 flows into the gate-source capacitance of the second switching means Q1 and charges it, so that the ON operation of the first switching means Q1 is backed up.

On the other hand, the second switching means Q
2 maintains the off state because the voltage drop of the resistor R2 is in the opposite direction.

Then, when the first switching means Q1 is turned on, the drain / source of the first switching means Q1 and the primary winding p of the unsaturated transformer NST are connected in series from the positive electrode of the rectified DC power supply RD. A current flows through the load circuit LC, that is, the resonance inductance L2, the DC cut capacitor C3, the resonance capacitor C4, and the path of the negative electrode of the rectified DC power supply RD. At this time, the series resonance circuit of the resonance inductance L2 of the load circuit LC, the DC cut capacitor C3, and the resonance capacitor C4 resonates, and the terminal voltage of the resonance capacitor C4 increases and is charged.

The primary winding p of the unsaturated transformer NST
, A voltage having a waveform proportional to the current waveform is induced in the secondary winding s. This induced voltage is shown in FIG.
The terminal without the polarity symbol attached to is higher. Note that the voltage drop of the primary winding p is higher at the terminal to which the polarity symbol is not attached in the figure.

On the other hand, the secondary winding s of the unsaturated transformer NST
Since the inductance Ln2 forms the drive resonance circuit DRC with the capacitance of the capacitor C5, the induced voltage of the secondary winding s resonates. The resonance voltage is applied to the first switching means Q via the capacitor C6.
A forward voltage is continuously applied between the gate and the source of the one, and the ON state is maintained.

On the other hand, since the resonance voltage is applied in the opposite direction between the gate and the source of the second switching means Q2, the second switching means Q2 remains in the off state.

However, since the polarity of the resonance voltage of the drive resonance circuit DRC is inverted next due to the vibration caused by the resonance, the gate-source voltage of the first switching means Q1 becomes a reverse voltage and turns off. Then, the voltage between the gate and the source of the second switching means Q2 becomes the polarity in the drive direction and turns on.

Therefore, the first switching means Q1
Is ON time of the capacitor C of the drive resonance circuit DRC.
5 and the inductance Ln2 of the secondary winding s of the unsaturated transformer NST.

When the first switching means Q1 is turned off, the electromagnetic energy stored in the resonance inductance L2 is released, and the parasitic inductance of the DC cut capacitor C3, the resonance capacitor C4, and the second switching means Q2 is released from the resonance inductance L2. The current continues to flow through the path of the diode, the primary winding p of the unsaturated transformer NST and the resonance inductance L2, but when the current becomes zero, the charge of the resonance capacitor C4 is reduced to the DC cut capacitor C3 and the resonance Inductance L2, primary winding p of unsaturated transformer NST, second switching means Q2,
The path of the resonance capacitor C4 is discharged, and current flows in the opposite direction. At this time, the voltage induced in the secondary winding s of the unsaturated transformer NST is higher at the terminal to which the polarity symbol is attached in the figure and lower at the other terminal. The first switching means Q1 to which resonance occurs in the resonance circuit DRC and the resonance voltage of which is applied via the drive circuit DC maintains an off state, and the second switching means Q2 maintains an on state.

However, when the resonance voltage of the drive resonance circuit DRC oscillates and the polarity is inverted, the first switching means Q1 is turned on again, and the second switching means Q2 is turned off.

As a result, after the electromagnetic energy stored in the resonance inductance L2 is released, a current flows from the positive electrode of the rectified DC power supply RD to the load circuit LC again as described first. Hereinafter, the operation described above is repeated to operate as a half-bridge type inverter.

When the resonance voltage of the drive resonance circuit DRC is applied between the gate and the source of the switching means Q1, Q2, the overvoltage portion is absorbed by the gate protection circuit GP, so that the gate is protected from the overvoltage. Is done.

In the load circuit LC, when a current flows through the resonance capacitor C4 during the operation described above, the current flows through the filament of the other electrode E2 of the discharge lamp DL to energize and heat the filament. Becomes a thermionic emission state, and since a high voltage due to resonance is applied between the electrodes E1 and E2, the discharge lamp of the load DL starts and lights up like an instant start.

When the discharge lamp of the load DL is turned on, the voltage between the electrodes E1 and E2 becomes a lamp voltage that is about half of the DC voltage, so that the resonance of the resonance capacitor C4 is relaxed. Voltage induction in proportion to the lamp current is continued in the primary winding p of the NST.

Hereinafter, the voltage waveforms of the primary winding p and the secondary winding s of the unsaturated transformer according to the present embodiment will be described with reference to FIGS. .

FIG. 3 is a waveform diagram showing the voltage of the primary winding of the unsaturated transformer in the first embodiment of the power supply device and the discharge lamp lighting device of the present invention when there is no load.

FIG. 4 is a waveform diagram showing the voltage of the secondary winding when no load is applied.

FIG. 5 is a waveform diagram showing the voltage of the primary winding under the same rated load.

FIG. 6 is a waveform diagram showing the voltage of the secondary winding under the same rated load.

In each figure, the horizontal axis represents time, and the vertical axis represents voltage. However, the voltage represents a voltage per scale in units (V / d).

As can be understood from the figures, in the present embodiment, the feedback from the load circuit is performed through the unsaturated transformer and the inductance Ln1 of the primary winding is small, In addition, since the inductance Ln2 and the equivalent inductance Ln2δ of the secondary winding are large, both at the time of load and at the time of rated load,
It clearly shows that the drive resonance circuit resonates with the fundamental wave of the current waveform flowing through the load circuit and the voltage of the primary winding is low.

Further, for comparison with the present invention, voltage waveforms at relevant portions in a prototype example similar to prior arts 3 and 4 will be described with reference to FIGS. The horizontal axis and the vertical axis are the same as in FIGS.

[0146] Figure 7 is a waveform diagram showing the voltage of a driving inductor L _D at no load in the prior art 3.

FIG. 8 is a waveform diagram showing the voltage of the second inductor 32 when no load is applied.

[0148] Figure 9 is a same waveform diagram showing a voltage of a resonant inductor L _R at the rated load.

[0149] Figure 10 is a same waveform diagram showing the voltage of a driving inductor L _D at the rated load.

FIG. 11 is a waveform diagram showing the voltage of the second inductor 32 under the same rated load.

As can be understood from the figures, the prior art 3 shows that the voltage drop of the resonant inductor that performs the current limiting action of the discharge lamp is large, and that this voltage is fed back.

FIG. 12 is a waveform diagram showing the voltage of the primary winding at the time of no load in the prior art 4.

FIG. 13 is a waveform diagram showing the voltage of the secondary winding when no load is applied.

FIG. 14 is a waveform diagram showing the voltage of the primary winding under the same rated load.

FIG. 15 is a waveform diagram showing the voltage of the secondary winding under the same rated load.

As can be understood from each figure, the voltage waveform is clearly different from that of the present embodiment because the prior art 4 uses a saturable transformer.

FIG. 16 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 17 is a conceptual sectional view of the unsaturated transformer.

In each figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, the DC cut capacitor C3
Is connected between the unsaturated transformer NST and the resonance inductance L2, and a bar core CO 'is used for the unsaturated transformer NST.

That is, the connection position of the DC cut capacitor C3 is determined by connecting the unsaturated transformer NST and the resonance inductance L
2 makes it easy to separate the unsaturated transformer NST from the resonance inductance L2 and to interpose the DC cut capacitor C3 between them, even on mounting. Since a kind of shielding effect is also obtained, interference between the two can be sufficiently suppressed.

The unsaturated transformer NST has a rod core C
O ′ and the primary winding p on the coil bobbin CB
And the secondary winding s is wound adjacently.

FIG. 18 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a third embodiment of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description is omitted.

In the present embodiment, the drive resonance circuit DRC '
Is different.

That is, the drive resonance circuit DRC '
The capacitance of the forming element is the switching means Q
1 and Q2 using the gate-source capacitance.

FIG. 19 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a fourth embodiment of the present invention.

In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the second switching means Q
2 ′ is different.

That is, the second switching means Q2 '
Is configured using an N-channel MOSFET in the same manner as the first switching means Q1. Therefore, the drain of the second switching means Q2 is connected to the source of the first switching means Q1, and the source is connected to the negative electrode of the rectified DC power supply RD.

Further, each of the switching means Q1,
In order to drive Q2, a drive circuit is provided for each switching means.

Further, in order to supply a resonance output to each of the drive circuits DC 1 and DC 2,
The first and second secondary windings s1 and s2 are wound.
The first secondary winding s1 forms a drive resonance circuit DRC with the capacitor C5, and is connected to the first drive circuit DC1 including the capacitor C6. Note that the gate protection circuit GP is omitted.

On the other hand, the second switching means Q
The second drive circuit DC2 for 2 ′ includes a second secondary winding s2 and a gate protection circuit GP. The second secondary winding s2 has a polarity opposite to that of the first secondary winding s1, and has both ends connected between the gate and source of the second switching means Q2 '. Further, the gate protection circuit GP is connected in parallel to the second secondary winding s2.

Thus, when a forward drive signal is induced in the first secondary winding s1 with respect to the first switching means Q1, the second secondary winding s2 is supplied with the second drive signal. Since a reverse drive signal is induced in the switching means Q2 ', the first and second switching means Q2'
1, Q2 'alternately performs switching.

Further, since the gate protection circuit GP is connected in parallel with the second secondary winding s2, the gate protection circuit GP is connected to the first secondary winding s1 magnetically coupled to about two secondary windings s2. It also performs a gate protection function.

FIG. 20 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a fifth embodiment of the present invention.

In the figure, the same parts as those in FIG. 19 are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, the configuration of the first and second switching means Q1 "and Q2" is different.

That is, the first and second switching means Q1 ", Q2" are composed of bipolar transistors. Since the bipolar transistor is a current drive type switching means, the drive resonance circuit DRC "and the first and second drive circuits CD
1 "and CD2" are also different.

The first switching means Q1 "has a collector connected to the positive electrode of the rectified DC power supply RD, and an emitter connected to the collector of the second switching means Q2".

The emitter of the second switching means Q2 "is connected to the negative electrode of the rectified DC power supply RD.

The drive resonance circuit DRC "is composed of the first secondary winding s1 of the unsaturated transformer NST and the capacitor C5.
Of the series resonance circuit.

The first drive circuit CD1 "comprises a capacitor C6 and a base protection circuit BP.

One end of the capacitor C6 is connected to the end of the drive resonance circuit DRC "on the capacitor C5 side, and the other end is connected to the base which is the drive terminal of the first switching means Q1".

The base protection circuit BP is composed of a series circuit of a diode D1 and a resistor R4. The cathode of the diode D1 is connected to the base of the switching means Q1 ".
The end on the resistor R4 side is connected to the emitter of the switching means Q1 ".

Thus, the base protection circuit BP protects the base of the bipolar transistor constituting the switching means Q1 "from being applied with an overvoltage.

The second drive circuit DC2 "includes the second secondary winding s2 of the unsaturated transformer NST, the capacitor C5, and the base protection circuit BP.

The second secondary winding s2 is connected to the first secondary winding s
One end is connected to the emitter of the second switching means Q2 "with the opposite polarity to the one.

One end of the capacitor C5 is connected to the other end of the second secondary winding s2, and the other end is connected to the base of the second switching means Q2 ".

The structure of the base protection circuit BP is the same as that of the first drive circuit DC2 ″.

FIG. 21 is a front view showing a bulb-type fluorescent lamp as one embodiment of the bulb-type discharge lamp of the present invention.

FIG. 22 is an enlarged longitudinal sectional view of a relevant part.

In each figure, 1 is a fluorescent lamp, 2 is a discharge lamp lighting device, 3 is an envelope, and 4 is a base.

In the fluorescent lamp 1, three U-shaped glass tubes are equally arranged so that both legs of the U-shape are located concentrically, and one glass tube is formed by a thin connecting tube. And a light-transmitting discharge vessel formed in a compact shape in which a bent discharge path is formed therein, and a phosphor layer disposed on the inner surface side of the light-transmitting discharge vessel And a pair of electrodes sealed at both ends of the translucent discharge vessel, and an ionizing medium containing an appropriate amount of mercury and a rare gas sealed inside the translucent discharge vessel.

The discharge lamp lighting device 2 has the circuit configuration shown in FIG.

The envelope 3 includes a light-transmitting globe 3a, a light-shielding substrate 3b, and a partition 3c located between the light-transmitting globe 3a and the light-shielding substrate 3b.

The translucent globe 3a has a bottomed cylindrical shape made of glass with a light diffusing coating formed on the inner surface.

The light-shielding substrate 3b has a cup shape formed by molding a white synthetic resin, and a light-transmitting globe 3a is fixed to an opening end of the substrate 3 by using a silicone adhesive 3d.

The partition 3c is formed by molding a white synthetic resin, and is fixed to the opening end of the light-shielding base 3b of the envelope 3 together with the translucent glove 3a by the silicone adhesive 3d.

[0200] The partition 3c divides the inside of the envelope 3 into a light-emitting room A and a circuit storage room B. Further, a fluorescent lamp support hole 3c1 and the like are formed in the partition 3c.

Thus, the fluorescent lamp 1 is supported by being fixed at both ends by inserting the both ends into the fluorescent lamp support hole 3c1 of the partition 3c with the silicone adhesive from the light emitting chamber A side.
The main part is arranged in the light emitting room A of the envelope 31.

The discharge lamp lighting device 2 comprises a substrate 2a and a circuit component 2b mounted on the substrate 2a.
c and is disposed in the circuit storage room B of the envelope 3.

The base 4 is mounted on the base end of the light-shielding base 3b of the envelope 3 and connected to the AC input end of the discharge lamp lighting device 2. The output end of the discharge lamp lighting device is connected to both electrodes of the fluorescent lamp 1. Connected to

[0204]

According to the first to sixth aspects of the present invention, at least the resonance inductance and the high-frequency AC operated by the high-frequency AC generated by the alternating switching of the first and second switching means connected in series between the DC power supplies. A load circuit having a resonant capacitance; an unsaturated transformer in which a voltage proportional to a current flowing through the load circuit is induced in at least the secondary winding; an inductance of the secondary winding of the unsaturated transformer; By providing a drive resonance circuit formed by capacitance and a drive circuit for alternately driving the first and second switching means by a resonance output of the drive resonance circuit, feedback of a current flowing through the load circuit is provided. Since the unsaturated transformers used in the transformers are small and can be obtained at low cost, we propose a power supply unit that is small and low in cost as a whole. It can be.

According to the second aspect of the present invention, the primary winding of the unsaturated transformer has an inductance that is negligibly small compared to the resonance inductance of the load circuit. It is possible to provide a power supply device that induces a voltage different from the resonance voltage of the circuit and proportional to the current flowing in the load circuit.

According to the third aspect of the present invention, in addition, the ratio Ln2 / Ln1 of the inductance Ln2 of the secondary winding to the inductance Ln1 of the primary winding of the unsaturated transformer is 100 or more. It is possible to provide a power supply device that forms a drive resonance circuit with the winding and the capacitance and obtains a drive signal necessary for driving the switching means.

According to the invention of claim 4, in addition to the inductance Ln2 of the secondary winding of the unsaturated transformer, the equivalent inductance Ln2δ existing in series with the secondary winding when the primary winding is short-circuited. When the ratio Ln2δ / Ln2 is 0.5 or more, it is possible to provide a power supply device having a resonance frequency suitable for generating high-frequency alternating current.

According to the fifth aspect of the present invention, in addition, since the first and second switching means are composed of complementary MOSFETs, a power supply device with a simplified drive circuit can be provided.

According to the invention of claim 6, the first and second switching means are formed of MOSFETs, and the capacitance of the drive resonance circuit is constituted by the gate-source capacitance of the switching means. Thus, the number of circuit components is small and the circuit configuration is simplified, so that a more compact and low-cost power supply device can be provided.

According to the seventh aspect of the present invention, in addition, the drive resonance circuit is constituted by the series resonance circuit formed by the inductance and the capacitance of the secondary winding of the unsaturated transformer. It is possible to provide a power supply device having a simple circuit configuration and capable of easily generating a required drive signal for driving the switching means.

According to the eighth aspect of the present invention, it is possible to provide a discharge lamp lighting device having the effects of the first to seventh aspects.

According to the ninth aspect of the present invention, it is possible to provide a bulb-shaped discharge lamp having the effects of the first to seventh aspects.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a power supply device and a discharge lamp lighting device of the present invention.

FIG. 2 is a conceptual cross-sectional view of the same unsaturated transformer.

FIG. 3 shows the first embodiment of the power supply device and the discharge lamp lighting device according to the present invention when the unsaturated transformer is not loaded.
Waveform diagram showing the voltage of the next winding

FIG. 4 is a waveform chart showing a voltage of a secondary winding when no load is applied.

FIG. 5 is a waveform chart showing the voltage of the primary winding under the same rated load.

FIG. 6 is a waveform diagram showing the voltage of the secondary winding under the same rated load.

Figure 7 is a waveform chart showing the voltage of a driving inductor L _D at no load in the prior art 3

FIG. 8 is a waveform chart showing a voltage of the second inductor 32 when no load is applied.

[9] Also waveform diagram showing a voltage of a resonant inductor L _R at rated load

[10] Also waveform diagram showing the voltage of a driving inductor L _D at rated load

FIG. 11 is a waveform chart showing a voltage of a second inductor 32 at the time of a rated load.

FIG. 12 is a waveform chart showing the voltage of the primary winding at the time of no load in the prior art 4;

FIG. 13 is a waveform chart showing the voltage of the secondary winding when no load is applied.

FIG. 14 is a waveform chart showing the voltage of the primary winding under the same rated load.

FIG. 15 is a waveform chart showing the voltage of the secondary winding under the same rated load.

FIG. 16 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 17 is a conceptual cross-sectional view of the same unsaturated transformer.

FIG. 18 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 19 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 20 is a circuit diagram showing a power supply device and a discharge lamp lighting device according to a fifth embodiment of the present invention.

FIG. 21 is a front view showing a bulb-type fluorescent lamp as one embodiment of the bulb-type discharge lamp of the present invention.

FIG. 22 is an enlarged sectional view of a main part of the same.

[Explanation of symbols]

 AS: Low frequency AC power supply f: Overcurrent fuse NF: Noise filter SA: Surge absorber C1: Capacitor L1: Inductor RD: Rectified DC power supply BRC: Bridge type full-wave rectifier circuit C2: Smoothing capacitor Q1: First switching means Q2 ... second switching means LC ... load circuit L2 ... resonance inductance C3 ... DC cut capacitor (resonance capacitance) C4 ... resonance capacitor (resonance capacitance) DL ... load E1 ... one electrode E2 ... other electrode NST ... Unsaturated transformer CO: Core p: Primary winding s: Secondary winding DRC: Drive resonance circuit C5: Capacitor DC: Drive circuit C6: Capacitor GP: Gate protection circuit ZDI: Zener diode ZD2: Zener diode ST: Starting circuit R1… Resistor R2… Resistor R3… Resistor Vessel

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K072 AA05 BA05 BC01 DD04 GA01 GA02 GA03 GB12 GB14 GC02 HB04 5H007 BB03 CA02 CB17 CB22 CC01 CC32 DB03 DC02

Claims (9)

[Claims] A first switching means and a second switching means connected in series between the DC power supplies; a first switching means and a second switching means having a resonance inductance and a resonance capacitance; A load circuit operated by a high-frequency alternating current generated by the alternate switching of the above; an unsaturated transformer in which a primary winding is connected to the load circuit and a voltage proportional to a current flowing through the load circuit is induced in the secondary winding; A drive resonance circuit formed by the capacitance and the inductance of the secondary winding of the unsaturated transformer; and a drive circuit that alternately drives the first and second switching means by a resonance output of the drive resonance circuit. A power supply device comprising: 2. The power supply according to claim 1, wherein the unsaturated transformer has a primary winding having an inductance that is negligible compared to the resonance inductance of the load circuit. apparatus. 3. The power supply device according to claim 2, wherein the ratio Ln2 / Ln1 of the inductance Ln2 of the secondary winding to the inductance Ln1 of the primary winding of the unsaturated transformer is 100 or more. . 4. The unsaturated transformer has a ratio Ln2 of an equivalent inductance Ln2δ existing in series with the secondary winding when the primary winding is short-circuited to the inductance Ln2 of the secondary winding.
3. The method according to claim 2, wherein δ / Ln2 is 0.5 or more.
Or the power supply device according to 3. 5. The power supply device according to claim 1, wherein said first and second switching means are constituted by complementary MOSFETs. 6. The first and second switching means comprises: M
6. The drive resonance circuit according to claim 1, wherein the drive resonance circuit has at least a capacitance between a gate and a source of the first switching means. Power supply. 7. The drive resonance circuit according to claim 1, wherein the inductance and the capacitance of the secondary winding of the unsaturated transformer constitute a series resonance circuit. Power supply. 8. A discharge lamp device, comprising: the power supply device according to claim 1; and a discharge lamp connected to a load circuit. 9. A discharge lamp body according to claim 8, supported by said discharge lamp body;
A bulb-type discharge lamp comprising: