JPS61161964A - Stabilized power source - Google Patents

Abstract

PURPOSE:To reduce the switching loss and to decrease a harmonic wave by loading a sinusoidal voltage between the collector and the emitter of a transistor, and applying a sinusoidal voltage to the primary coil of an inverter transformer. CONSTITUTION:When a DC voltage V0 is applied, transistors Q2, Q3 are alternately turned OFF to generate sinusoidal currents at the primary coils Np1, Np2 of an inverter transformer T1. The DC output V1 obtained from the secondary side of the transformer T1 is compared by an error amplifier A1 with a reference input voltage VR, and a signal output in response to the difference is supplied to the base of a transistor Q4. Since the collector of the transistor Q4 is connected with saturable reactors Ls1, Ls2, the reset amounts of the reactors Ls1, Ls2 are controlled to cancel the variation in the output V1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a multi-output type stabilized power supply device capable of outputting both stabilized direct current and stabilized alternating current.

[Technical background of the invention and its problems] Conventionally, a multi-output stabilized power supply device has been used as a multi-output type stabilized power supply device that supplies stabilized power to DC loads such as electronic devices and AC loads such as fluorescent lamps. The device shown in FIG. 2 is known.

The figure shows a stabilized power supply device with inverters provided on the primary and secondary sides, where Vo is the supplied DC, Ql is the switching transistor, and T1
is an inverter transformer, NP is its primary coil, Ns is its secondary coil, Di and C2 are rectifying diodes, LI is a choke coil, and C1 is a smoothing capacitor.

Further, A1 is an error amplifier circuit that compares the DC output V+ obtained from the secondary coil Ns with the reference voltage VR and outputs a signal according to the difference, O20 is an oscillation circuit that outputs a triangular wave,
PWM converts the triangular wave output from the oscillation circuit O8C into a pulse of the same frequency, and the pulse width of the pulse is combined with the triangular wave output from the oscillation circuit O8C and the error amplification circuit AI.
OR indicates a driver circuit that amplifies the pulse output from the pulse width modulation circuit PWM and applies it to the base of the transistor Q1.

Zarani INV is the DC output v obtained from the secondary coil N8
1 is input, an inverter performs switching to obtain alternating current, T2 is a transformer that transforms the obtained alternating current, Cp is a capacitor for waveform shaping, and RL is an alternating current load to which alternating current output v2 is applied.

In the stabilized power supply device configured in this way, the square wave current obtained by the switching action of the transistor Q1 is
It is rectified by diodes DI and C2 connected to the secondary coil Ns, smoothed by a choke coil L1 and a capacitor C1, and converted into a DC output v1.

The DC output V+ is then input to the error amplifier circuit A1 and compared with the reference input voltage VR, and a signal corresponding to the difference is output to the pulse width modulation circuit PWM.

As mentioned above, in the pulse width modulation circuit PWM, the triangular wave output from the oscillation circuit O8C is converted into a pulse of the same frequency, but at this time, the pulse width of this pulse is determined by the rising slope of the triangular wave and the output of the error amplifier circuit A1. It is varied based on the position of the cross point with the signal.

This pulse is amplified by the driver circuit OR and applied to the base of transistor Q1, so transistor Q
The duty factor of 1 is controlled according to the output of the error amplifier circuit A1, and as a result, the DC output
The voltage value of 1 is always held constant.

On the other hand, the stabilized DC output ■1 is inverter IN
It is input to V, is converted into AC by its switching action, is boosted by transformer T2, is roughly shaped by capacitor CF, and is applied to AC load RL.

Note that when driving a load RL such as a discharge lamp with such a stabilized power supply, an AC voltage that is 3 to 5 times higher than the steady state voltage is required at the start of discharge, but the voltage on the output side of the transformer T1 is Since a capacitor CF is inserted to lower the output voltage of the transformer T2 to obtain a steady voltage for the load RL, there is no voltage drop due to the capacitor CF at the start of discharge when no current is flowing through the load RL. At the start of discharge, high voltage alternating current is applied to load RL.

However, such a stabilized power supply device has a problem in that the circuit configuration is complicated because switching circuits are provided on the primary side and the secondary side, respectively, as described above.

Also, on the primary side, the primary coil N of the inverter transformer T1
Since a square wave voltage is applied to p, its primary coil NP
Ripple alternating current is generated due to the coupling capacitance Os between and the secondary coil Ns, but since this alternating current is in-phase alternating current, it returns to the primary coil Np side through the ground line on the secondary coil Ns side, and a corresponding It becomes in-mode noise containing high frequency components.

However, in such a device, there is a problem in that a large line filter must be provided on the input side in order to attenuate common mode noise.

[Object of the Invention] The present invention was made to solve the problems of the conventional stabilized power supply device as described above, and provides a stabilized power supply device that generates less common-mode noise and has a simple circuit configuration. It is an object.

[Summary of the Invention J In other words, the stabilized power supply device of the present invention includes a first coil to which direct current is applied, a first switching transistor connected in series to the coil, and a magnetic field connected to the first coil. at least two second coils coupled together;
a third coil magnetically coupled to the coil and connected to the base of the first transistor; a saturable reactor connected in series to either of the second coils; and a rectifier connected to the coil.・An error amplifier circuit that compares the output voltage of the same coil with a reference voltage and outputs a signal according to the difference, and a fourth circuit that controls the saturation timing of the saturable reactor using the same signal as a base current. It is characterized by having two transistors and a waveform shaping transistor connected in series to another coil.

[Embodiments of the Invention] Hereinafter, details of embodiments of the present invention will be described based on the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and parts common to those in FIG. 2 are given the same reference numerals.

In the same figure, Vo is the input DC current, Lr is the choke coil, Q2 and C3 are switching transistors that are turned on and off alternately, T+ is an inverter transformer,
NPI and NF2 are their primary coils, No is the drive coil connected to the bases of transistors Q2 and 03, CP
indicates a resonant capacitor inserted in parallel with primary coils NP1 and NF2.

The above part is a so-called resonant inverter, and can generate a sine wave voltage in the primary coils Np+ and NF2.

Note that the switching operation using two transistors as described above is generally called a push-pull operation.

Also, N+s+ and N82 are inverter transformer T1
The secondary coils, Ls+ and LS2 are the secondary coils Ns+
and a saturable reactor connected in series with N82, D
I, C2, and C3 are rectifying diodes, Ll is a choke coil, and C1 is a smoothing capacitor.

Further, Nss is a secondary coil for AC output, CF is a capacitor for waveform shaping, and RL is an AC load.

Furthermore, A1 is an error amplifier circuit that inputs the DC output v1, compares it with the reference voltage V, and outputs a signal according to the difference;
4 is the signal-base current, while the collector is connected to the saturable reactor LS via diodes D4 and 05.
It shows a transistor connected to I, Ls2 and whose emitter is connected to the DC output v1.

Next, the operation of the stabilized power supply device of this embodiment configured as described above will be explained.

First, when DC Vo is supplied, a current flows to the bases of transistors Qz and Qs via resistors R1 and R2, and one of transistors Q2 and Qs turns on (which one turns on first does not matter). not definitive).

Assume that transistor Q2 is first turned on and voltage Vo is applied to primary coil NP+ of inverter transformer T1.

In this case, a voltage obtained by dividing the DC human power Vo is induced in the drive coil NO magnetically coupled to the primary coil NP+ according to its turns ratio, and a reverse bias is applied to the base-emitter circle of the transistor Q3. The off state of transistor Q3 is maintained. At this time, 1 of inverter transformer T1
The voltage generated in the next coil Np+ is sinusoidal.

Here, the inductance of the primary coil NP1 of the inverter transformer T+ is LH% The conversion value to the primary coil NP+ of the resonant capacitor CP is CP'% The waveform shaping capacitor C
When the converted value of F to the primary coil Np+ is CF/, the self-excited oscillation angular frequency ω is given by ω1/M P+F.

When the voltage of the primary coil NP+ crosses 0 volts while drawing a sinusoidal arc and moves in the negative direction, the induced voltage of the drive coil No changes similarly.

Therefore, the induced voltage in the drive coil NO, which had been applied to the base of the transistor Q3 as a reverse bias voltage, now changes to a forward bias. Conversely, a reverse bias is applied to the base of transistor Q2, and as a result, transistor Q3 is turned on and transistor Q2 is turned off. This causes self-oscillation to enter a negative half cycle.

As the transistors Q2 and 03 are alternately turned on and off, a sine wave current is generated in the primary coils Np1 and NP+. And this current is the secondary coil N
st and Nsz.

At this time, if the saturable reactor Ls I N Ls z is not provided, the sine wave current is full-wave rectified by the diode D+, 03, and the choke coil L1
is smoothed by capacitor C1 and obtained as DC voltage ■1, but as it is, DC output V1 becomes DC human power Vo
It fluctuates as the .

Therefore, in order to stabilize this output voltage (1), saturable reactors Ls+ and LS2 are inserted in series with the secondary coils NSt and NS2, respectively, to control the phase.

For the saturable reactors Ls+ and Ls2, the phase control angle indicating the saturation timing is determined by the reset amount of the magnetic flux, and as the amount of reset increases, the phase control angle increases and the output voltage decreases.

The DC output ■1 is compared with the reference input voltage VR in the error amplifier circuit A1, and the signal output according to the difference is used as the base current of the transistor Q4, but the collector of the transistor Q4 is connected to the saturable reactors Ls+ and Lsz. Since it is connected, the reset amount of the saturable reactor LSI 182 is controlled to cancel the fluctuation of the DC output v1.

Therefore, the DC output v1 is always kept at a constant voltage.

Further, the AC obtained from the secondary coil Ns3 is supplied to the AC load RL via a waveform shaping capacitor Cp.

By the way, transistors Qz and Qs have an accumulation time, and transistors Q2 and Qs have storage time.
When the sine wave voltage generated at the terminal 2 becomes 0 port, the switch turns on at the same time, but a choke coil LP is provided on the DC input side to limit the short circuit current at this time.

In addition, in the embodiment described above, the secondary coil Nss for AC output
A capacitor CF is used as a waveform shaping element.
A choke coil may be inserted instead of the capacitor Cp.

In that case, the self-oscillation angular frequency ω′ is ω’-1/P//FP It is.

Note that / represents the inductance of the choke coil LP converted to the primary fill Np+, and LP//LF' represents the combined inductance of the choke coil LP and the inductances L and l.

As explained above, in the stabilized power supply device of this embodiment, the transistors Qz and Qs bear the sinusoidal voltage between the collector and emitter, so the voltage becomes approximately 0 volts at turn-on and turn-off, reducing switching loss.

Furthermore, since a sinusoidal voltage is applied to the primary coil of the inverter transformer T1, fewer harmonics are generated than when a square wave voltage is applied.

Furthermore, since the IBJ phase current flowing to the secondary coil side through the coupling chamber C8 between the primary coil and secondary coil of the inverter transformer is reduced, there is no need to increase the size of the input steel line filter.

Furthermore, as described above, since the switching loss is reduced, the switching frequency can be increased, and as a result, the inverter transformer T+ can be downsized.

[Effects of the Invention] As explained above, the stabilized power supply device of the present invention includes a first coil to which direct current is applied, a first switching transistor connected in series to the coil, and a first transistor. at least two second coils magnetically coupled to the coil; a third coil magnetically coupled to the first coil and connected to the base of the first transistor; connected in series to either of the second coils; a saturable reactor connected to the same coil, a rectifier/smoothing circuit connected to the same coil, an error amplification circuit that compares the output voltage of the same coil with a reference voltage and outputs a signal according to the difference, and a signal based on the same signal. It has a second transistor that controls the saturation timing of the saturable reactor as a current, and a waveform shaping element connected in series to another coil, so a sine wave is applied to the first coil, and as a result, , less conductive noise is generated, and the circuit configuration is simpler.

Furthermore, since the switching frequency can be increased, the transformer can be made smaller and the device itself can be made more compact.

In addition, since the number of transformers is reduced, the insulation area between the primary and secondary sides is reduced, simplifying the insulation design.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the stabilized power supply device of the present invention, and FIG. 2 is a circuit diagram showing the configuration of a conventional stabilized power supply device. Np + , NP 2...Primary fill N
il～N83・・・・・・Secondary coil No.
・・・・・・・・・・・・・・・・・・Drive coil Q1-Q4・・・・・・・・・・・・Transistor D1-D4・・・・・・・・・・・・・・・Diode L81. L82......Supersaturation reactor LP, Ll...Choke coil CP, CF N CI...Capacitor A+...・・・・・・・・・・・・・・・・・・
・Error amplification circuit RL・・・・・・・・・・・・・・・・
・・・・・・・・・AC Load Agent Patent Attorney Suyama
- Figure 1 Figure 2 Procedures Amendment Voluntary) March 5, 1986, Day 2, Title of the invention: Stabilized power supply device 3, Intermediary with the case of the person making the amendment/Patent applicant Yosaki, Kanagawa Prefecture Toshiba Corporation 4, 72 Horiyo-cho (307), Ichisaiwai-ku, Agent Address: 2-1 Kanda Tamachi, Chiyoda-ku, Tokyo 101 Full text and drawings of the specification/-16, Contents of amendments Revised
Correct details Maro 1, Title of the invention Stabilized power supply device 2, connected to the claimed error amplification circuit and the secondary coil of 1, and according to the output signal of the front surge difference increase circuit, generates a front surge.
(5) A resonance capacitor is connected in parallel to the first primary coil. (6) The stabilized power supply device W according to any one of Claims 1 to 5, wherein the waveform shaping element is a capacitor. - A stabilized power supply device according to any one of claims 1 to 5, wherein the waveform shaping element is a choke coil. 3. Detailed Description of the Invention [Technical Field of the Invention J The present invention relates to a multi-output stabilized power supply device capable of outputting both stabilized direct current and stabilized alternating current. [Technical background of the invention and its problems] Conventionally, a multi-output type stabilized power supply lIM that supplies stabilized power to DC loads such as electronic devices and AC loads such as fluorescent lamps has been used. The device shown in FIG. 2 is known. The figure shows a stabilized power supply device with inverters installed on the primary and secondary sides. In the figure, Vo is the supplied DC, Ql is the switching transistor, and T+
is an inverter transformer, NP is its primary coil, Ns is its secondary coil, D and D2 are rectifying diodes, L+ is a choke coil, and SC+ is a smoothing capacitor. Further, A1 is an error amplifier circuit that compares the DC output V+ obtained from the secondary coil N8 and the reference voltage vR and outputs a signal according to the difference, O20 is an oscillation circuit that outputs a triangular wave,
PM converts the triangular wave output from RWa times MO8C into a pulse of the same frequency, and the pulse width of the pulse is combined with the triangular wave output from the oscillation circuit O8C and the error amplification circuit A+.
OR indicates a driver circuit that amplifies the pulse output from the pulse modulation circuit PM and applies it to the base of the transistor Q+. Furthermore, INV is the DC output V obtained from the secondary coil Ns.
+ is input to an inverter that performs switching to obtain alternating current, T2 is a transformer that transforms the obtained alternating current, CF is a capacitor for waveform shaping, and RL is an alternating current load to which alternating current output ■2 is applied. In the stabilized power supply device configured in this way, the square wave current obtained by the switching action of the transistor Q+ is
Diodes D+ and Dzk connected to the secondary coil Ns:
II flows from choke coil [1 and capacitor C1
is converted into a DC output V+. Then, the DC output v1 is input to the error amplifier circuit A+ and compared with the reference input voltage VR, and a signal corresponding to the difference is generated J(
The signal is output to the pulse modulation circuit PM. As mentioned above, in the pulse modulation circuit PM, the triangular wave output from the oscillation circuit O8C is converted into a pulse of the same frequency, but at this time, the pulse width of this pulse is determined by the rising slope of the triangular wave and the output of the error amplifier circuit A1. It is varied based on the position of the cross point with the signal. This pulse is layer-width-widthed by the driver circuit OR and applied to the base of the transistor QI.
The duty factor of + is controlled according to the output of the error amplifier circuit A+, and as a result, the DC output ■
The voltage value of 1 is always held constant. On the other hand, the stabilized DC output V+ is connected to the inverter IN
The voltage is input to V, is converted into AC by its switching action, is boosted by transformer T2, is further shaped by capacitor CF, and is applied to AC load RL. In addition, when driving a negative r4RL such as a discharge lamp with such a stabilized power supply, an AC voltage that is 3 to 5 times higher than the normal voltage is required at the start of discharge, but the output side of the transformer T1 A capacitor CF is inserted in the transformer T2 to lower the output voltage of the transformer T2 to obtain a steady voltage for the load RL, so that the load RL1. :1I8i! At the start of discharge when no current is flowing, no voltage drop occurs due to the capacitor CF, and at the start of discharge, a high voltage alternating current is applied to the load RclC. However, such stabilization WIWAIIIll
As described above, since switching circuits are provided on the primary side and the secondary side, there is a problem in that the circuit configuration is complicated. Also, on the primary side, the primary coil N of the inverter transformer T+
Since a square wave voltage is applied to p, its primary coil NP
Ripple alternating current is generated due to the coupling capacitance ICg between and the secondary coil Ns, but since this alternating current is in-phase alternating current, it returns to the primary coil NP side through the ground line on the secondary coil Ns side, causing a corresponding It becomes in-mode noise containing high frequency components. However, in such a device, there is a problem in that a large line filter must be provided on the input side in order to attenuate common mode noise. [Object of the Invention] The present invention has been made in order to solve the problems of the conventional stabilized power supply device as described above. intended to provide. [11111 of the Invention That is, the stabilized power supply device of the present invention includes a first coil to which a direct current is applied, a secondary coil magnetically coupled to the first primary coil, and a secondary coil connected in series to the first primary coil. a first switching element connected to the first switching element, and by turning on/off a current flowing through the first primary coil by the first switching element, a desired voltage output is provided to the second secondary coil. In the stabilized power supply device configured to obtain the following, the first switching element has a control input terminal for switching control, and the primary coil is connected to at least a first secondary coil and a second secondary coil. a drive coil magnetically coupled to the first primary coil and connected to a control input terminal of the first switching element; a voltage output obtained at the first secondary coil; and a reference voltage. and an error amplification @ path which compares and outputs a signal according to the difference, and which is connected to the first secondary coil and which is connected to the
The on-width of the first secondary coil is adjusted and output according to the output signal of the I-difference amplifier circuit 1iIII! 11 circuit, a rectifying normal temperature circuit that rectifies and smoothes the output of this on-width IIIa circuit and outputs a DC voltage, and a waveform shaping element that is connected to the second secondary coil and outputs an AC voltage. It is characterized by the fact that [Embodiments of the Invention] Hereinafter, details of embodiments of the present invention will be described based on the drawings. FIG. 1 is a circuit diagram showing an embodiment of the present invention, and parts common to those in FIG. 2 are given the same reference numerals. In the figure, Vo is an input DC current, LP is a choke coil, Q2 and Q3 are switching transistors that are turned on and off alternately, T+ is an inverter transformer, and N
PI and Np2 are their primary coils, No is the drive coil connected to the bases of transistors Q2 and 03, CP
indicates a resonant capacitor inserted in parallel with primary coils NP1 and NF2. In this embodiment, bipolar transistors Q2 and Q3 are used as switching elements, but MOS-F
It is also possible to use switching elements such as ET, GTO thyristors, thyristors, etc. Note that when using a thyristor, a waveform shaping circuit may be required between the coil NO and the l1llII terminal of the thyristor or the like. Furthermore, when using a thyristor, it is necessary to add a commutation circuit for turn-off. The above part is a so-called resonant inverter, and can generate a sine wave voltage in the primary coils NP+ and NF2. Note that the switching operation using two transistors as described above is generally called push-pull operation. Also, N S + and Na3 are inverter transformer T
1 secondary coil, Ls+ and LS2 are secondary coil Ng
+ and a saturable reactor connected in series with Na3,
DI, D2. D3 is a rectifying diode, the tail is a choke coil, and C+ is a smoothing capacitor. Further, NS3 represents a secondary coil for AC output, OF represents a capacitor for waveform shaping, and RL represents an AC load. Furthermore, A+ is an error amplifier circuit that inputs the DC output V+, compares it with the reference voltage ■, and outputs a signal according to the difference.
4, the signal is passed to the base 2I, while the collector is connected to the saturable reactor L via diodes D4 and D5.
s+, Lsz, and the emitter is connected to the DC output V+. In this embodiment, the bipolar transistor Q4 is used as the current control element and IJ, but it may be replaced with an element such as a MOS-FET whose output current section can be controlled by a control signal. Next, the operation of the stabilized power supply device of this embodiment configured as described above will be explained. First, when DC Vo is supplied, a current flows to the bases of transistors Q2 and Qs via resistors R1 and R2, and one of transistors Q2 and Q3 turns on (which one turns on first does not matter). not definitive). Assume that transistor Q2 is first turned on and voltage Vo is applied to primary coil NpI of inverter transformer T1. In this case, a voltage obtained by dividing the DC human power Vo is induced in the drive coil NO magnetically coupled to the primary coil NP+ according to its turns ratio, and a reverse bias is applied to the base-emitter terminal of the transistor Q3. The off state of transistor Q3 is maintained. At this time, 1 of inverter transformer T1
The voltage generated in the next coil Np+ is sinusoidal. Here, the inductance of the primary coil NP of the inverter transformer T1 is LM, the conversion value of the resonant capacitor OP to the primary coil NP+ is Cr2, and the waveform shaping capacitor C
When the conversion value of F to the primary coil NP+ is CF2, the self-excited imaging angle frequency ω is given by ω-1/HP'+CF'). Then, when the voltage of the primary coil Np+ crosses O volts while drawing a sinusoidal arc and changes in the negative direction, the induced voltage of the drive coil No changes similarly. Therefore, the induced voltage in the drive coil No, which had been applied to the base of the transistor Q1 as a reverse bias voltage, now changes to a forward bias. Conversely, a reverse bias is applied to the base of transistor Q2, and as a result, transistor Q3 is turned on and Q2 is turned off. This causes the self-help lift to enter a negative half cycle. As the transistors Q2 and 03 are alternately turned on and off, a sine wave N current is generated in the primary coils Np and Np+. And this ms is the secondary coil N
It is extracted from s+ and NS2. At this time, if the saturable vectors Ls+ and Ls2 were not provided, the sine wave current would flow through the diode D+,
The DC voltage V+ is obtained by full-wave rectification by Os and smoothing by the choke coil L1 and capacitor CI, but if left as is, the DC output V+ will fluctuate as the DC input Vo changes. Therefore, in order to stabilize this output voltage ■1, the saturable reactor Ls+ and 182 are connected to the secondary coils Ns1 and NS12.
These are inserted in series with each other, and the phase 1ilIIIl is performed. For the saturable reactors Lg+ and Lgz, the phase l1m11 angle indicating the saturation timing is determined by the reset amount of magnetic flux, and as the reset peak becomes larger, the phase control angle becomes larger and the output voltage decreases. The DC output V+ is compared with the reference input voltage v in the error amplifier circuit A1, and a signal output according to the difference is made to flow to the transistor Q4, but the collector of the transistor Q4 is connected to the saturable reactor Lg+. , Lsz, the reset amount of the saturable reactors Ls + and Ls 2 is set to VtW so as to cancel the fluctuation of the DC output v1. In this way, the DC output v1 is always kept at a constant voltage. In this example, a saturable reactor is used to reduce noise on the secondary side of the transformer, but the saturable reactor functions as an on-time scheduler for the current flowing through the coil Ns 11Ns 2, and the transistor It may be replaced with a switching element such as. Further, the AC obtained from the secondary coil Ns3 is supplied to the AC load RL via a waveform shaping capacitor CF. By the way, transistors Q2 and Q3 have storage time, and transistors Q2 and Qs have storage time between primary coils NPI and Np.
When the sine wave voltage generated at the terminal 2 becomes O port, the switch turns on at the same time, but in order to limit the short circuit current at this time, a choke coil LP is provided on the DC input side. In addition, in the embodiment described above, the secondary coil Nss for AC output
A capacitor CF is used as a waveform shaping element.
A choke coil may be inserted in place of the capacitor CF. In that case, the self-oscillation angular frequency ω' is ω'=1/P/F p. Note that L F l represents the inductance of the choke coil LF converted to the primary coil NPI, and LPjLF' represents the combined inductance of the choke coil LP and the inductances L and l . As explained above, in the stabilized power supply device of this embodiment, the transistors Qz and Q3 bear the sinusoidal voltage at the collector-emitter stage, so the voltage becomes approximately 0 port at turn-on and turn-off, reducing switching loss. Furthermore, since a sinusoidal voltage is applied to the primary coil of the inverter transformer T+, fewer harmonics are generated than when a square wave voltage is applied. Furthermore, since the in-phase alternating current flowing to the secondary coil side through the coupling capacitance ICs between the primary coil and secondary coil of the inverter transformer is reduced, there is no need to increase the size of the line filter on the input side. Furthermore, as described above, since the switching loss is reduced, the switching frequency can be increased, and as a result, the inverter transformer T1 can be downsized. [Advantageous Effects of the Invention 1] As explained above, in the stabilized power supply device of the present invention, since a sine wave is applied to the first coil, less conductive noise is generated, and the circuit configuration is relatively pure. In addition, since the switching frequency can be increased, the transformer can be made smaller and the equipment itself can be made more compact.In addition, since the number of transformers is reduced, the connection between the primary and secondary sides can be reduced. 4. Brief explanation of the drawings Fig. 1 is a circuit diagram showing the configuration of an embodiment of the stabilized power supply device of the present invention, and Fig. 2 is a circuit diagram showing the configuration of an embodiment of the stabilized power supply device of the present invention. FIG. 2 is a circuit diagram showing the configuration of a stabilized power supply device.

Claims (5)

[Claims] (1) a first coil to which direct current is applied; a first switching transistor connected in series to the coil; at least two second coils magnetically coupled to the first coil; a third coil magnetically coupled to the first coil and connected to the base of the first transistor; a saturable reactor connected in series to either of the second coils; an error amplifier circuit that compares the output voltage of the coil with a reference voltage and outputs a signal according to the difference; and controls the saturation timing of the saturable reactor using the same signal as a base current. A stabilized power supply device comprising a second transistor and a waveform shaping element connected in series to another secondary coil. (2) The stabilized power supply device according to claim 1, wherein two first transistors are connected to the first coil, and switching is performed by a push-pull method. (3) The stabilized power supply device according to claim 1 or 2, wherein a resonance capacitor is connected in parallel to the first coil. (4) The stabilized power supply device according to any one of claims 1 to 3, wherein the waveform shaping element is a capacitor. (5) The stabilized power supply device according to any one of claims 1 to 3, wherein the waveform shaping element is a choke coil.