JPH10163042A - Transformer and switching power circuit - Google Patents

Abstract

(57) Abstract: providing a magnet MG against cost and size / weight A core of the orthogonal drive transformer T1 of the switching power supply circuit, a control current flowing through the control winding N _C The magnetic flux φ _{C2 in the} direction opposite to the magnetic flux φ _C1 generated by I _C is generated constantly. As a result, in a state where the control current does not flow through the control winding and the magnetic flux φ _C1 is not generated, the resonance impedance of the resonance type switching power supply circuit is maintained at a high state, thereby preventing the destruction of components such as the switching element. . This eliminates the need to provide a soft start circuit, an overvoltage protection circuit, and the like in the power supply circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer and a switching power supply circuit, for example, a self-excited switching power supply circuit and an orthogonal transformer provided for controlling a constant voltage in such a switching power supply circuit. It is.

[0002]

2. Description of the Related Art For example, as a drive transformer for driving a switching element of a self-excited current resonance type converter, a quadrature transformer having a quadrature saturable reactor is provided by the applicant of the present invention. A configuration that enables control has been proposed.

FIG. 6 shows an example of the configuration of such an orthogonal drive transformer. The orthogonal drive transformer T shown in this figure is provided with cores CR1 and CR2 each having four magnetic legs formed as shown in the drawing, and the four magnetic legs of the cores CR1 and CR2 are opposed to each other. To form the main body core CR. Then, the wound around the drive winding N _B as shown in FIG across magnetic leg of the predetermined two of the main body core CR as a controlled winding, its winding direction with respect to the controlled winding orthogonal so as to be formed by winding a control winding N _C over a predetermined 2 magnetic legs of. The drive winding N _B is, for example, an inductor having an inductance Lb of forming a self-oscillating circuit of the switching element. The control winding N _C, the control current I _C of the DC to that level in response to secondary side output voltage level of the power supply circuit to which the orthogonal drive transformer T is provided is variable is supplied.

[0004] The constant voltage control by the orthogonal drive transformer T having the above configuration is performed as follows. Here, a case where a self-excited current resonance type converter is employed as the switching converter will be described. In a self-excited current resonant converter, for example,
A converter for transmitting the switching output to the secondary side, a primary side series resonance circuit is formed by the inductance of the primary winding of the converter transformer and the capacitance of the series resonance capacitor connected in series to obtain a current resonance type operation. Is done.

The level of the control current I _C changes in accordance with the fluctuation of the output voltage level on the secondary side of the power supply circuit.
Assuming that the secondary-side output voltage level changes in the increasing direction, the control current I _C is also controlled to increase. Figure 7 is a view showing an inductance Lb drive winding N _B on the level of the control current I _C to be supplied to the control winding N _C, the level of the control current I _C as can be seen from this figure increases in response to the inductance Lb drive winding N _B is controlled to decrease. In this way, by the inductance Lb drive winding N _B is controlled to vary, for example, the capacitance of the capacitor that forms a self-oscillating circuit together with the inductance Lb When Cb, 1 / 2π (Lb · Cb) The oscillation frequency of the self-excited oscillation circuit determined by ^1/2 changes. That is, the switching frequency of the switching element is variably controlled. As a result, the switching frequency (the oscillation frequency of the self-excited oscillation circuit) changes with respect to the resonance frequency set for the above-described primary-side series resonance circuit. Therefore, the primary-side series resonance circuit viewed from the switching output side. (Hereinafter referred to as resonance impedance) also changes accordingly.

[0008] Such impedance characteristics are shown in FIG. 8, which shows the resonance impedance Z in relation to the switching frequency f. In this figure, the frequency fa is the resonance frequency of the primary side series resonance circuit, and the impedance becomes lowest at this frequency fa.
Then, the constant voltage control system provided with orthogonal drive transformer T, as the operating range corresponding to the level variable range of the control current I _C, as shown in FIG. 8, than the resonance frequency fa of the primary side series resonant circuit switching frequency is configured to be variable in a range of high frequency f ₁ (the upper-side). By variably controlling the resonance impedance in the operation range shown in this figure, the current level supplied to the primary winding forming the primary side series resonance circuit as a switching output changes. As a result, the output transmitted on the secondary side via the converter transformer changes, and the secondary side output voltage is controlled to be constant.

[0007] For example, when the secondary output voltage varies to rise, by the level of the control current I _C is increased accordingly, the inductance of the drive winding N _B is reduced. As a result, the impedance Z changes to increase as the switching frequency is controlled to increase within the operation range shown in FIG. As the impedance Z increases in this way, the level of the current flowing through the primary winding of the converter transformer forming the primary side series resonance circuit is suppressed, and the level of the secondary side output voltage is reduced. Is done.

[0008]

By the way, in the configuration for performing the constant voltage control of the self-excited power supply circuit by the above configuration, for example, at the time of startup, the control winding N _{C is} still required.
When the secondary side is temporarily short-circuited by an excessive charging current generated when the secondary side rectifying electrolytic capacitor is charged in a state where the control current I _C is not flowing to the secondary side,
This influence may affect the primary side, and component elements such as switching transistors may be destroyed. When the control current I _C does not flow due to a defect such as disconnection of the control winding N _C of the orthogonal drive transformer, as can be seen from FIG. 8, the oscillation frequency of the self-excited oscillation circuit of the switching element is changed to the primary side series. The resonance frequency fa of the resonance circuit becomes the closest, and the state where the impedance of the primary side resonance circuit is the lowest is maintained. In such a state, for example, a state in which an excessive switching output is supplied from the switching element to the primary-side series resonance circuit is continued.
Switching elements and the like may be destroyed.

As a countermeasure, for example, a soft start circuit that operates using an auxiliary power supply is provided to prevent a temporary short-circuit on the secondary side.
An overvoltage protection circuit is provided to protect the circuit by, for example, stopping the switching operation when the constant voltage control by the orthogonal drive transformer becomes impossible and the secondary output voltage rises abnormally. I have. However, by providing the soft start circuit and the overvoltage protection circuit, the number of components is increased accordingly, which hinders the promotion of cost reduction and reduction in size and weight of the power supply circuit itself.

[0010]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a controlled winding having a predetermined function and a winding direction orthogonal to the controlled winding. And a control winding supplied with a control current whose level is varied so as to obtain a predetermined control target value. A magnetic flux generating means for generating a second magnetic flux in a direction opposite to the direction of the first magnetic flux generated by flowing the current is provided. Further, the controlled winding is an inductance forming a self-excited oscillation circuit for driving the switching element in a self-excited manner.

Further, in a switching power supply circuit that performs a resonance type switching operation by inputting a rectified and smoothed voltage obtained by rectifying and smoothing a commercial power supply, a controlled winding having a predetermined function; A control winding provided with a winding direction orthogonal to the winding and supplied with a control current whose level is varied such that a predetermined control target value is obtained for a secondary output voltage level And a magnetic flux generating means for generating a second magnetic flux in a direction opposite to the first magnetic flux generated by passing a control current through the control winding. And an orthogonal transformer.

According to the above configuration, in a state where the control current does not flow through the control winding of the orthogonal transformer, the magnetic flux in the opposite direction to the magnetic flux generated when the control current flows through the control winding is effective. Become. Thus, for example, when the controlled winding is an inductor forming a self-excited oscillation circuit in a self-excited resonance type switching power supply circuit, control is performed so that the switching frequency is the highest in a predetermined operation range. As a result, the resonance impedance of the resonance type power supply circuit is maintained at the highest state corresponding to the switching frequency.

[0013]

FIG. 1 is a circuit diagram schematically showing a configuration example of a switching power supply circuit according to an embodiment of the present invention. The switching power supply circuit shown in this figure is provided with a self-excited current resonance type switching converter. The power supply circuit shown in this figure uses a DC power supply E1 as an operation power supply. This DC power supply E1 can be obtained, for example, by a rectifying and smoothing circuit that actually receives a commercial AC power supply and performs rectification and smoothing.

The self-excited current resonance type converter shown in FIG. ₁ is provided with _two switching elements Q ₁ and Q ₂ half-bridge-coupled as shown in the figure, and performs switching operation using the DC power supply E1 as an operation power supply. Do. In this case, the collector of the switching element Q ₁ is a direct current power source E1
Is connected to the positive electrode, the emitter is connected to the collector of the switching element Q _2. The emitter of the switching element Q ₂ is connected to the negative electrode of the DC power supply E1.

Further, starting resistors R _S1 and R _S2 are inserted between the collectors and the bases of the switching elements Q ₁ and Q ₂ , respectively. Further, a resistor R _B1 inserted between each base of the switching elements Q ₁ and Q ₂ and a self-excited oscillation circuit described later,
The R _B2, adjusts the base current of the switching element Q _1, Q ₂ (drive current). Further, the bases of the switching elements Q _1, Q ₂ - each clamp diode between the emitter D _B1, D _B2 is inserted. The resonance capacitors C _B1 and C _B2 together with the drive windings N _B1 and N _{B2 of} the orthogonal drive transformer T to be described below form a series resonance circuit (self-excited oscillation circuit) for driving the switching element by self-excited oscillation. Has formed. The collector of the switching element Q ₂ - capacitor C ₂ connected in parallel to emitter has a function of absorbing the switching noise generated by the switching operation of the switching element Q _1, Q _2.

An orthogonal drive transformer T (Power Regula)
The ting transformer drives the switching elements Q ₁ and Q ₂ and variably controls the switching frequency. The orthogonal drive transformer T includes drive windings N _B1 , N _B
An orthogonal type in which a control winding N _C wound so that the winding direction is orthogonal to _{B 2} and a resonance current detection winding N _D provided to wind up the drive winding N _B1 is provided. Saturable reactor. The drive winding N _B1 is
One end of the resonant capacitor C _B1 - is connected to the base of switching element Q ₁ via the resistor R _B1, the other end is connected to the emitter of the switching element Q _1. Further, one end of the drive winding N _B2 is grounded to the negative electrode of the DC power source E1,
The other end resonant capacitor C _B2 - via a resistor R _B2 is connected to the base of the switching element Q _2, drive winding N _B1
A voltage having a polarity opposite to that of the above is output.

The converter transformer T2 includes a primary winding N ₁
And the secondary windings N _2A and N _2B are wound. One end of the primary winding N ₁ of the converter transformer T2, series resonant capacitor C ₁ - resonance current detecting winding N through a series connection junction point of the emitter and collector of the switching element Q ₂ of the switching element to Q _{1 D} ( Switching output point). The other end of the primary winding N ₁ is connected to the negative electrode of the DC power supply E1. According to the above connection configuration, the primary winding N ₁ and the series resonant capacitor C ₁ of the converter transformer T2
Is to be connected in series, the inductance component of the converter transformer T2 which wound a primary winding N ₁ and the series resonant capacitor C ₁ by the capacitance to the switching converter and the operation of the current resonance type Form a series resonant circuit. Then, a switching output obtained by the switching operation of the switching elements Q ₁ and Q ₂ is supplied to this series resonance circuit.

On the secondary side of the converter transformer T2, a full-wave rectifier circuit including secondary windings N _2A and N _2B , rectifier diodes D ₁ and D ₂ and a smoothing capacitor C _O is formed. The switching output obtained in the primary winding N ₁ is excited by the secondary windings N _2A and N _2B , so that the DC secondary-side output voltage E _O is extracted from the full-wave rectifier circuit. .

The switching operation of the current resonance type converter described so far is as follows. First,
For example, when a commercial AC power supply is turned on, the DC power supply E1 is turned on.
Is obtained, the starting resistors R _S1 and R _{S2 are} supplied from the DC power supply E1.
A base current is supplied to the bases of the switching elements Q ₁ and Q ₂ via the switch. For example, if the switching element Q ₁ is turned on _first , the switching element Q ₂ is controlled to be turned off. Is done. And as the output of the switching element Q _1, the resonance current detecting winding N _D → series resonant capacitor C ₁ → primary winding N ₁ to the resonance current flows, but the switching element Q in the vicinity of the resonance current becomes 0
₂ is turned on, the switching element Q ₁ is controlled so as to be turned off. The reverse resonant current flows from the preceding through the switching element Q _2. Thereafter, a self-excited switching operation in which the switching elements Q ₁ and Q ₂ are turned on alternately is started. As described above, the switching elements Q ₁ and Q ₂ alternately open and close using the DC power supply E 1 as an operation power supply, thereby supplying a drive current close to the resonance current waveform to the primary winding N ₁ of the converter transformer T 2.

The control circuit 1 shown in FIG. 1 is composed of, for example, an error amplifier. The control circuit 1 supplies a control current I _C , which is a DC current of a variable level according to a change in the secondary output voltage E _O , to the control winding N _C of the orthogonal drive transformer T1. And the orthogonal drive transformer T
1, the switching elements Q ₁ and Q _{1 are} controlled by the control current I _C supplied to the control winding N _C as described later.
By changing the switching frequency of ₂ , the constant voltage control is performed.

FIG. 2 shows the structure of the orthogonal drive transformer T1 shown in FIG. 1, and the same parts as those in FIG. 6 are denoted by the same reference numerals. The orthogonal drive transformer T1 according to the present embodiment shown in this figure also has two cores CR1 and CR2 each formed to have four magnetic legs, similarly to the orthogonal drive transformer T shown in FIG. C
R2 is provided, and the main body CR is formed by combining the four magnetic legs of the cores CR1 and CR2 so as to face each other. Also in this case, the drive windings N _B1 and N _B2 are wound as controlled windings over two predetermined magnetic legs in the main body core CR as shown in FIG. its winding as directions are perpendicular, it is wound the control winding N _C over a predetermined 2 magnetic legs of Te. Incidentally, the second is the state where one set of windings is wound is illustrated in wound portion of this figure drive windings N _B1, N _B2, actually drive winding N _B1 and N _B2 A pair of windings are wound in a state where they are insulated from each other. Also,
According to FIG. 1, the actual orthogonal drive transformer T1 but is what is wound also current detecting winding N _D, where for convenience of description, are not shown.

In the orthogonal drive transformer T1 of the present embodiment, the magnet MG is provided so as to be attached to the outer side surface of the core CR2 as shown in the figure. In the present embodiment, for example, when the control current I _C is applied to the control winding N _C , the magnetic flux φ in the direction indicated by the dashed arrow in FIG.
_C1 is generated. On the other hand, the magnet MG constantly generates the magnetic flux φ _C2 to the main body core CR. The magnetic flux φ _C2 is attached, for example, so that a hatched portion of the magnet MG becomes an N pole, thereby generating a magnetic field in a direction indicated by a solid thick arrow in the drawing in the main body core CR. That is, the magnet MG is provided to generate a magnetic flux φ _C2 in a direction opposite to the magnetic flux φ _C1 .

FIG. 3 shows drive windings N _B1 , N _B in the orthogonal drive transformer T1 of the present embodiment shown in FIG.
The characteristics of each inductance Lb of _B2, shows the relationship between the level of the control current I _C. In orthogonal drive transformer T1, by constantly flux phi _C2 is generated by the magnet MG, the control current I to the control winding N _{C
In a} state where _C is not flowing, for example, the main body core CR is in a saturated state, and thus the inductance Lb of the drive windings N _B1 and N _B2 is very small as shown in FIG. When the control current I _C flows through the control winding N _C , the above-described magnetic flux φ _C1 is generated. As the level of the control current I _C increases, the magnetic field strength of the magnetic flux φ _C1 also increases. It will become stronger. Since the direction of this magnetic flux φ _C1 is opposite to the magnetic flux φ _{C2 of the} magnet MG, as the magnetic flux φ _C1 becomes stronger,
The function of canceling the magnetic flux φ _{C2 of the} magnet MG becomes stronger. As a result, as shown in FIG. 3, as the level of the control current I _C increases, the saturation of the main body core CR is weakened, and the inductance Lb
Means that the characteristics of increasing are obtained. This characteristic has, for example, the opposite characteristic to the inductance characteristic shown in FIG. 7 as a conventional example.

For this reason, in the switching power supply circuit of FIG. 1 provided with the orthogonal drive transformer T1 having the characteristic shown in FIG. 3, for example, as the secondary output voltage E _O fluctuates so as to increase, The control circuit 1 is configured to supply a control current I _C, which is varied so that the level falls within a predetermined range, to the control winding N _C. As a result, also in the present embodiment, it is possible to control the resonance impedance of the power supply circuit by changing the switching frequency within the same operation range as described above with reference to FIG. That is, if the secondary-side output voltage E _O fluctuates so as to increase, the control circuit 1 controls the level of the control current I _C to decrease, thereby decreasing the inductance Lb. . Thus, the switching frequency is the resonance impedance of the switching power supply circuit is increased as high resonance current flowing through the primary winding N ₁ is reduced. As a result, the level of the secondary output voltage E _O is suppressed, and the secondary output voltage E _O can be stabilized.

In the switching power supply circuit of the present embodiment having the orthogonal drive transformer T1, for example, when the secondary side is short-circuited by the initial charging of the smoothing capacitor at the time of startup, or when the control winding N _The control current I _C is changed to the control winding N
_Let's consider the situation where it does not flow to _C. In such a state, as described with reference to FIG. 3, the inductances Lb of the drive windings N _B1 and N _B2 are kept at the minimum. As a result, the switching frequency f (the oscillation frequency of the self-excited oscillation circuit) becomes the highest state corresponding to the value of the inductance Lb. Then, the resonance impedance described with reference to FIG. 8 is also controlled to have the highest value corresponding to the switching frequency. Thus, for example, the current level to be supplied to the primary winding N ₁ as switching output is limited, the possibility of component elements including the mentioned above switching elements and the like in the conventional example are destroyed so that extremely low Is done. Therefore, in the switching power supply circuit of the present embodiment as shown in FIG. 1, there is no need to provide a soft start circuit that operates using an auxiliary power supply or an overvoltage protection circuit.

FIG. 4 shows a configuration example of a quadrature drive transformer as another embodiment of the present invention. In this figure, the same parts as those in FIG. In orthogonal drive transformer T1-A shown in the figure, for example, with respect to a substantially central portion of the two magnetic legs which wound the control winding N _C, respectively attached so as to sandwich the magnet MG1, MG1 .
Also in this case, the mounting is performed in consideration of the polarity so as to generate a magnetic flux φ _C2 in a magnetic field direction indicated by a thick broken arrow in the drawing. Even with such a configuration, the same characteristic of the inductance Lb as in FIG. 3 can be obtained. Further, in the case of the orthogonal drive transformer T1-A, since the magnets MG1 and MG1 are attached so as to be sandwiched between the magnetic legs, the size and weight of the transformer itself are, for example, the conventional one shown in FIG. Is equivalent to
This is advantageous in terms of reducing the size and weight. During the manufacture of the orthogonal drive transformer T1-A, the magnets MG1, MG1
1 and then the cores CR1 and CR2 may be joined together. It is also conceivable to provide the magnet MG1, MG1 for the remaining two magnetic legs portion of which is not wound around the control winding N _C.

FIG. 5 shows an example of the configuration of a quadrature drive transformer as another embodiment of the present invention. Note that, in this figure, the same parts as those in FIGS. In the orthogonal drive transformer T1-B shown in this figure, a magnet is not provided, but a sub-control winding N _C1 is wound in a winding direction parallel to the control winding N _C. The sub-control winding N _C1 is configured to constantly flow the sub-control current I _C1 at a predetermined level having a polarity opposite to the control current I _C flowing through the control winding N _C. Thus, the magnetic flux φ _C2 is constantly generated during the operation of the power supply circuit, and the characteristic of the inductance Lb shown in FIG. 3 is obtained. When the orthogonal drive transformer T1-B shown in FIG. 5 is provided in the switching power supply circuit as shown in FIG.
For example, although not shown, it is necessary to add an auxiliary power supply circuit for obtaining the sub-control current I _C1 .

It should be noted that the present invention is not limited to the configuration of the embodiment described above, and various changes can be made. For example, the mounting position of the magnet MG, MG1 or the like depends on the actual use situation. It may be changed. Also, the shape and structure of the orthogonal transformer itself are shown in FIG.
The invention is not limited to those shown in FIGS. Further, the configuration of the switching power supply circuit having the orthogonal transformer as the present invention is not limited to the one shown in FIG. 1, and various types of configurations that can adopt various types of control by having the orthogonal transformer are provided. Switching power supply circuit,
Further, the present invention can be applied to various devices other than the power supply circuit.

[0029]

As described above, according to the present invention, the orthogonal transformer is provided with magnetic flux generating means for generating a magnetic flux in a direction opposite to a magnetic flux generated by passing a control current through the control winding. As a result, when no control current flows through the control winding, the inductance of the controlled winding is maintained at the lowest level by the action of the magnetic flux of the magnetic flux generating means. As a result, the resonance impedance of the resonant switching power supply circuit is reduced. Can be maintained at a high level, but this function prevents the destruction of components such as switching elements even when the control current is not supplied to the control winding due to a secondary short circuit at start-up or some failure. It is possible to do. Therefore, it is not necessary to provide a soft start circuit, an overvoltage protection circuit, and the like in the power supply circuit, so that the cost can be reduced and the size and weight of the circuit can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating a configuration example of a switching power supply circuit according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a structural example of an orthogonal drive transformer as an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an inductance characteristic with respect to a control current level of the orthogonal drive transformer of the present embodiment.

FIG. 4 is a perspective view showing a structural example of an orthogonal drive transformer as another embodiment.

FIG. 5 is a perspective view showing a structural example of an orthogonal drive transformer as still another embodiment.

FIG. 6 is a perspective view showing a structural example of a conventional orthogonal drive transformer.

FIG. 7 is an explanatory diagram showing inductance characteristics with respect to a control current level of the orthogonal drive transformer shown in FIG. 6;

FIG. 8 is an explanatory diagram showing a resonance impedance characteristic with respect to a switching frequency when a constant voltage control is performed with the orthogonal drive transformer.

[Explanation of symbols]

1 control circuit, E1 DC power supply, T1, T1-A, T1
−B orthogonal drive transformer, T2 converter transformer, Q ₁ , Q ₂ switching element, C ₁ series resonance capacitor, N ₁ primary winding, N _B1 , NB ₂ drive winding, N
_C control winding, I _C control current CR body core, CR
1, CR2 core, MG, MG1 magnet, N _C1 sub-control winding, I _C1 sub-control current, φ _C1 , φ _C2 magnetic flux

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[Procedure amendment]

[Submission date] November 28, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

The level of the control current I _C changes in accordance with the fluctuation of the output voltage level on the secondary side of the power supply circuit.
Assuming that the secondary-side output voltage level changes in the increasing direction, the control current I _C is also controlled to increase. Figure 7 is a view showing an inductance Lb drive winding N _B on the level of the control current I _C to be supplied to the control winding N _C, the level of the control current I _C as can be seen from this figure increases in response to the inductance Lb drive winding N _B is controlled to decrease. In this way, by the inductance Lb drive winding N _B is controlled to vary, for example, when the capacitance of the capacitor that forms a self-oscillating circuit together with the inductance Lb and Cb, 1 / {2π (Lb Cb) The oscillation frequency of the self-excited oscillation circuit determined by ^{1/2 1/2} changes. That is, the switching frequency of the switching element is variably controlled. As a result, the switching frequency (the oscillation frequency of the self-excited oscillation circuit) changes with respect to the resonance frequency set for the primary-side series resonance circuit described above, and thus the primary-side series resonance circuit viewed from the switching output side. (Hereinafter referred to as resonance impedance) also changes accordingly.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009] As a countermeasure, for example by providing a soft-start circuit to operate using an auxiliary power supply, temporarily Inn
Circuit for increasing the impedance Z and providing an overvoltage protection circuit to stop the switching operation when the secondary side output voltage rises abnormally due to the inability of the quadrature drive transformer to perform constant voltage control. We are trying to protect. However, by providing the soft start circuit and the overvoltage protection circuit, the number of components is increased accordingly, which hinders the promotion of cost reduction and reduction in size and weight of the power supply circuit itself.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

Further, starting resistors R _S1 and R _S2 are inserted between the collectors and the bases of the switching elements Q ₁ and Q ₂ , respectively. Further, a resistor R _B1 inserted between each base of the switching elements Q ₁ and Q ₂ and a self-excited oscillation circuit described later,
The R _B2, adjusts the base current of the switching element Q _1, Q ₂ (drive current). Further, the bases of the switching elements Q _1, Q ₂ - each clamp diode between the emitter D _B1, D _B2 is inserted. The resonance capacitors C _B1 and C _B2 together with the drive windings N _B1 and N _{B2 of} the orthogonal drive transformer T1 described below form a series resonance circuit (self-excited oscillation circuit) for driving the switching element by self-excited oscillation. Has formed. The collector of the switching element Q ₂ - capacitor C ₂ connected in parallel to emitter has a function of absorbing the switching noise generated by the switching operation of the switching element Q _1, Q _2.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

An orthogonal drive transformer T1 (Power Regu
lating Transformer) includes switching elements Q ₁ , Q ₂
And variably controls the switching frequency.
The orthogonal drive transformer T1 includes drive windings N _B1 , N _B
An orthogonal type in which a control winding N _C wound so that the winding direction is orthogonal to _{B 2} and a resonance current detection winding N _D provided to wind up the drive winding N _B1 is provided. Saturable reactor. The drive winding N _B1 is
One end of the resonant capacitor C _B1 - is connected to the base of switching element Q ₁ via the resistor R _B1, the other end is connected to the emitter of the switching element Q _1. Further, one end of the drive winding N _B2 is grounded to the negative electrode of the DC power source E1,
The other end resonant capacitor C _B2 - via a resistor R _B2 is connected to the base of the switching element Q _2, drive winding N _B1
A voltage having a polarity opposite to that of the above is output.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

FIG. 2 shows the structure of the orthogonal drive transformer T1 shown in FIG. 1, and the same parts as those in FIG. 6 are denoted by the same reference numerals. The orthogonal drive transformer T1 as the present embodiment shown in this figure also has the two cores CR1 and CR2 formed to have four magnetic legs, respectively, similarly to the orthogonal drive transformer T shown in FIG. C
R2 is provided, and the main body CR is formed by combining the four magnetic legs of the cores CR1 and CR2 so as to face each other. Also in this case, the drive windings N _B1 and N _B2 are wound as controlled windings over two predetermined magnetic legs in the main body core CR as shown in FIG. its winding as directions are perpendicular, it is wound the control winding N _C over a predetermined 2 magnetic legs of Te. Incidentally, the second is the state where one set of windings is wound is illustrated in wound portion of this figure drive windings N _B1, N _B2, actually drive winding N _B1 and N _B2 A pair of windings are wound in a state where they are insulated from each other. Also,
According to FIG. 1, the actual orthogonal drive transformer T1 but is what is wound also current detecting winding N _D, where for convenience of description, are not shown.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

In the orthogonal drive transformer T1 of the present embodiment, the magnet MG is provided so as to be attached to the outer side surface of the core CR2 as shown in the figure. In the present embodiment, for example, when the control current I _C is applied to the control winding N _C , the magnetic flux φ in the direction indicated by the dashed arrow in FIG.
_C1 is generated. On the other hand, the magnet MG constantly generates the magnetic flux φ _C2 with respect to the main body core CR . The magnetic flux φ _C2 is attached, for example, so that a hatched portion of the magnet MG becomes an N pole, thereby generating a magnetic field in a direction indicated by a solid thick arrow in the drawing in the main body core CR. That is, the magnet MG is provided to generate a magnetic flux φ _C2 in a direction opposite to the magnetic flux φ _C1 .

Claims (6)

[Claims] A controlled winding having a predetermined function and a winding direction perpendicular to the controlled winding are provided so that a predetermined control target value can be obtained. In a transformer of an orthogonal type in which a control winding to which a control current whose level is variable is supplied is wound, in a direction of a first magnetic flux generated by flowing the control current through the control winding, And a magnetic flux generating means for generating a second magnetic flux in a direction opposite to this. 2. The magnetic flux generating means according to claim 1, wherein the magnetic flux generating means is a magnet provided to a core forming the transformer so as to obtain the second magnetic flux.
Transformer. 3. The magnetic flux generating means is a winding wound around the transformer, and is configured to generate the second magnetic flux by a DC current supplied to the winding. The transformer according to claim 1, wherein: 4. The transformer according to claim 1, wherein the controlled winding is an inductance forming a self-excited oscillation circuit for driving a switching element in a self-excited manner. 5. A controlled winding assumed to have a predetermined function in a switching power supply circuit which performs a resonance type switching operation by inputting a rectified and smoothed voltage obtained by rectifying and smoothing a commercial power supply, A control winding provided with a winding direction orthogonal to the winding and supplied with a control current whose level is varied such that a predetermined control target value is obtained for a secondary output voltage level And a magnetic flux generating means for generating a second magnetic flux in a direction opposite to the first magnetic flux generated by flowing the control current through the control winding. A switching power supply circuit comprising: an orthogonal transformer. 6. The switching power supply circuit according to claim 5, wherein the controlled winding is an inductance forming a self-excited oscillation circuit for driving a switching element by a self-excited method.