JP2002058244A - Switching power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the loss of a switching circuit part and improve the conversion efficiency. SOLUTION: This switching power supply device comprises: a rectifying smoothing means which generates rectified smoothed voltage across a smoothing capacitor, using the rectified current obtained by rectifying commercial AC power as a charge current; a switching means which performs the switching action, with the above rectified smoothed voltage as action power; an oscillation drive means which controls the switching frequency, being connected to the switching means; a switching output means which makes the above switching action a current resonance type, with a resonance capacitor connected in series to the primary winding of a converter transformer constituted in insulation type; a means which controls the switching frequency, using a control signal obtained from the output of a high-voltage rectifying circuit connected to high-voltage winding being provided as the secondary winding of the above converter transformer; an inductance control means which controls the inductance of a saturable reactor being connected to another secondary winding of the above converter transformer; and a means which performs the adjustment of amplitude in a horizontal deflection circuit and the compensation of bobbin distortion, using the above saturable reactor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply for supplying a plurality of output voltages including a high voltage for use in a television receiver or a monitor display device.

[0002]

2. Description of the Related Art In a computer display monitor for displaying a high-resolution video signal, the frequency has been further increased, and as a technical problem, power loss and heat generation of an insulation type switching power supply circuit, a horizontal deflection circuit, and a high voltage generation circuit have become problems. Has become.

[0003] In the case of a conventional high-definition deflection high-voltage device for displaying a high resolution, the high-voltage circuit is formed as a separate circuit while avoiding the influence on the deflection circuit. The reason is that the multi-scan system in which the operating frequency of the deflecting device automatically follows the input signal is generally used, and the deflection operation is not always constant, such as that the amplitude adjustment of the horizontal amplitude is open to the user. This is because a high voltage cannot be stably obtained from the deflection pulse.

A conventional switching power supply device will now be described with reference to FIGS. 10 to 1 showing the configuration and circuit operation of an insulated switching power supply circuit, a horizontal deflection circuit, and a high voltage generating circuit.
5 will be described. In a switching power supply device such as a television receiver or a monitor display device, as shown in FIG. 10, a circuit system for a horizontal deflection yoke 207 and a cathode ray tube 211 is roughly divided into a power supply circuit portion, a horizontal deflection circuit portion, and a high voltage generation circuit. A circuit section is provided. The power supply circuit section includes an AC rectifying / smoothing circuit 201, an oscillation driving circuit 2
02, a converter circuit 203 and a converter transformer circuit 204 are provided. The horizontal deflection circuit for the horizontal deflection yoke 207 includes a horizontal amplitude adjustment and pincushion distortion correction circuit 23.
9, a horizontal oscillation drive circuit 205 and a horizontal output circuit 206 are provided. The high voltage generation circuit section for the cathode ray tube 211
An oscillation drive circuit 208, a high voltage output circuit 209, and a high voltage transformer 210 are provided.

In the power supply circuit section, an AC rectifying / smoothing circuit 201
Supplies a rectified current obtained by rectifying a commercial AC power supply as a charging current to a smoothing capacitor, and generates a rectified smoothed voltage across the smoothing capacitor. The rectifying and smoothing voltage obtained from the AC rectifying and smoothing circuit 201 is used as an operation power source, and the converter circuit 203 is caused to perform a switching operation by using a driving pulse obtained from the oscillation driving circuit 202. The converter transformer in the converter transformer circuit 204 includes:
It is excited by the switching operation of converter circuit 203, and an output voltage is obtained from this converter transformer. The extracted output voltage is used as a power source for the horizontal deflection circuit and the high voltage generation circuit.

[0006] The output voltage from the converter transformer circuit 204 supplied as a power source for the horizontal deflection circuit unit is supplied to a horizontal output circuit 206 after voltage modulation is performed by a horizontal amplitude adjustment and pincushion distortion correction circuit 239. . The horizontal output circuit 206 is supplied with a driving pulse obtained from the horizontal oscillation driving circuit 205. The horizontal output circuit 206 performs a switching operation using the driving pulse, and supplies a deflection current to the horizontal deflection yoke 207. Further, the output voltage from the converter transformer circuit 204 supplied as the power supply of the high voltage generation circuit unit is supplied to the high voltage output circuit 209. The high-voltage output circuit 209 is supplied with a drive pulse obtained from the high-voltage oscillation drive circuit 208. The high-voltage output circuit 209 performs a switching operation by using the driving pulse, excites the high-voltage transformer 210, generates a high voltage in the high-voltage transformer 210, and supplies a high voltage to the anode of the cathode ray tube 211.

FIG. 11 shows the circuit configuration in each block of FIG. 10 in detail. AC rectification smoothing circuit 201
, A bridge rectifier diode 213 is provided for an AC power supply 212 to perform a full-wave rectification operation, and a rectified smoothed voltage is obtained by a smoothing capacitor 214. The rectified smoothed voltage is supplied to the oscillation drive circuit 2 via the resistor 215.
02 and to the converter circuit 203.

In the converter circuit 203, the switching elements Q1 and Q2 of the switching section 216 form a half-bridge circuit so that the switching elements Q1 and Q2
The resonance capacitor 219 and the choke coil 220 and the primary winding 22 of the insulation type converter transformer 221 are connected to the contact between the source of the switching element Q2 and the drain of the switching element Q2.
2 are connected in series. Damper diodes 217 and 218 are connected to switching elements Q1 and Q2. The drain of the switching element Q1 is connected so that a rectified and smoothed voltage from the AC rectifying and smoothing circuit 201 is supplied. Power is supplied to the oscillation drive circuit 202 from the rectified and smoothed voltage from the AC rectification and smoothing circuit 201 through the resistor 215. The oscillation drive circuit 202 is connected so that rectangular drive pulses having different polarities for alternately turning on and off every half cycle are supplied to the gates of the switching elements Q1 and Q2. An excitation type current resonance type converter circuit is configured.

The basic operation of the current resonance type converter circuit constituted by the half bridge circuit will be schematically described with reference to FIG. In FIG. 12A, the DC voltage source 274
Corresponds to a rectified smoothed voltage. The inductor 275 is
An inductor having a combined inductance formed by the choke coil 220 and the primary winding 222 of the converter transformer 221 is shown, and a resistor 276 is a resistor schematically showing the internal resistance of the circuit. 12B and 12C, the switches S1 and S2 of the switching unit 216 indicate the switching states of the switching elements Q1 and Q2, respectively, and the currents IQ1 and IQ2 are the switching elements Q1 and Q2.
, I1 indicates a current flowing through the resonance capacitor 219, the inductor 275, and the resistor 276.

In FIG. 12A, an oscillation driving circuit 202
FIG. 12B shows an equivalent circuit when a positive driving pulse is supplied to the re-switching element Q1 and the re-switching element Q1 is turned on. At this time, the switching element Q1 turns on and the switch S1
Is closed, the equivalent circuit includes a DC voltage source 274, a resonance capacitor 219, an inductor 275, and a resistor 276.
And a positive resonance current flows through the switch S1 using the DC voltage source 274 as a power supply. Next, an equivalent circuit when a positive drive pulse is supplied to the switching element Q2 and turned on is as shown in FIG. 12C, and a negative resonance current flows through the resonance capacitor 219, the inductor 275, and the resistor 276.

FIG. 13 shows a current waveform of each part flowing through the equivalent circuit shown in FIG. Switching elements Q1, Q2
The waveforms of the currents IQ1 and IQ2 flowing through and the resonance current I1 flowing through the series resonance circuit are as shown in the figure.

FIG. 14 shows the relationship between the current I1 flowing through the series resonance circuit shown in FIG. 12 and the frequency f. 14, f0 indicates the resonance frequency of the series resonance circuit of FIG. 12, and fsw indicates the repetition operation frequency of the switching unit 216 driven by the oscillation drive circuit 202.
Resonant capacitor 219, interactor 275, resistor 276
Are C, L, and R, respectively, and the admittance is obtained by setting the impedance of the series resonance circuit to each frequency ω as Z. The admittance Y is represented by (Equation 1).

(Equation 1)

The resonance frequency f0 of the series resonance circuit is expressed by (Equation 2).

(Equation 2)

In the above (Equation 1), since the current I is proportional to the admittance Y, the curve of FIG. 14 shows the magnitude of the current I1 with respect to the frequency using the current I, and the maximum of the resonance current at the resonance frequency f0 is shown. Give a value. The repetition operation frequency fsw of the switching unit 16 is set to satisfy fsw> f0 so as to move along the right side of the resonance curve.

The operation of the current resonance type converter circuit 203 in FIG. 11 will be described as follows based on the above basic operation. As the switching operation of the power supply circuit of FIG. 11, first, when the commercial AC power supply 212 is turned on, a rectified current obtained by rectifying the commercial AC power supply 212 with the bridge rectifier diode 213 is used as a charging current as described above. A rectified smoothed voltage is generated at both ends of the smoothing capacitor 214. The rectified and smoothed voltage is used as an operation power supply,
Power is supplied to the oscillation drive circuit 202 through 5, and a positive drive pulse is supplied from the oscillation drive circuit 202 to the switching element Q1 included in the re-switching unit 216 to be turned on. Then, a positive resonance current is supplied to the resonance capacitor 219 and the primary winding 222 of the converter transformer 221 through the switching element Q1. Next, a negative drive pulse is supplied to the switching element Q1, and conversely, a positive drive pulse is supplied to the other switching element Q2 forming the switching unit 216, and the switching element Q1 is turned off rapidly. Then, the switching element Q2 is turned on. As a result, a negative resonance current is supplied to the resonance capacitor 219 and the primary winding 222 of the converter transformer 221 through the switching element Q2, and the re-converter transformer 221 is excited by a series resonance current obtained by repeating this operation. Secondary windings 223, 2 wound on the secondary side of converter transformer 221
Alternating output voltages are extracted from 24, 225 and 226.

In the converter transformer circuit 204,
The converter transformer 221 includes the primary winding 222 to which the exciting current is supplied as described above, and the secondary windings 223, 2
A rectifying / smoothing circuit for extracting a DC voltage from the alternating output voltage is connected to 24, 225 and 226. For example, it becomes the power supply voltage of the horizontal deflection circuit section and high voltage generation circuit section,
It is configured to obtain a so-called + B voltage and another voltage used as a power supply voltage of a signal circuit. That is, a diode constituting the rectifier circuit 227 and the smoothing capacitors 230 and 231 are connected to the secondary winding 223 as shown in the figure, and the + B voltage E0 is extracted by the double voltage half-wave rectification method. For the secondary windings 224 and 225, a diode forming the rectifier circuit 228 and the smoothing capacitor 2
32 and 233 are connected as shown, and a positive voltage E3 and a negative voltage E4 are taken out. A voltage E2 by the half-wave rectification method is extracted from the secondary winding 226 by the rectifier diode 229 and the smoothing capacitor 234.

The constant + B voltage obtained from the secondary winding 223 of the converter transformer 221 and serving as the power supply voltage for the horizontal deflection circuit and the high voltage generating circuit is set as follows. For example, when the luminance of the image displayed on the cathode ray tube increases and the high voltage load fluctuates as a result, or when the horizontal amplitude of the image displayed on the cathode ray tube changes to increase, The load increases. As a result, the voltage value E0 of the + B voltage tends to fluctuate so as to decrease. Therefore, this voltage fluctuation is taken out by the voltage detection circuit unit composed of the resistors 235 and 236, and the control circuit 237 amplifies the error. The signal is sent to the oscillation drive circuit 202 which controls and drives the frequency of the switching unit 216 through a photocoupler 238 for insulating the control system. Then, the oscillation drive circuit 202
In accordance with the voltage from 38, the operation frequency of the drive pulse output to the switching unit 216 is controlled so as to decrease. As a result, the switching frequency fsw of the switching elements Q1 and Q2 decreases.

Conversely, the brightness of the image displayed on the cathode ray tube decreases, and as a result, the high-voltage load fluctuates so as to decrease, or the horizontal amplitude of the image displayed on the cathode green tube decreases. In this case, since the + B voltage E0 fluctuates so as to increase, the control signal is sent to the oscillation drive circuit 202 through the photocoupler 238 as described above, and the drive pulse output from the oscillation drive circuit 202 according to this voltage. Is controlled so as to increase the operating frequency. as a result,
Switching frequency fs of switching elements Q1, Q2
w rises.

In this power supply circuit, the series resonance capacitor 2
19, choke coil 220 and converter transformer 2
The switching frequency fsw of the switching unit 216 composed of a half-bridge converter is set higher than the resonance frequency of the series resonant circuit composed of the 21 primary windings 222. Therefore, in the case described above, + B
When the voltage load increases, the + B voltage E0 fluctuates so as to decrease. Therefore, the switching frequency fsw is controlled to decrease. At this time, the switching frequency fs is controlled with respect to the resonance frequency f0 of the series resonance circuit in FIG.
As w approaches, as a result, the excitation current flowing through the primary winding 222 increases, and a constant voltage is measured. Conversely, when the load of the + B voltage decreases, the + B voltage E
Since the switching frequency fsw changes to increase, the switching frequency fsw is controlled to increase, and the switching frequency fsw is separated from the resonance frequency f0 of the series resonance circuit. As a result, the exciting current flowing through the primary winding 222 of the converter transformer 221 is suppressed,
A constant voltage will be measured. At this time, the secondary windings 224, 225, 22
The other voltages E2, E3, E4 taken out from 6 are
By the so-called cross regulation, a constant voltage is roughly achieved.

The + B voltage thus obtained is supplied to a horizontal output circuit 206 after being subjected to voltage modulation by a horizontal amplitude adjustment and pincushion distortion correction circuit 239. Horizontal output circuit 2
To 06, a drive pulse obtained from the horizontal oscillation drive circuit 205 is supplied. Then, using the driving pulse, the horizontal output circuit 206 performs a switching operation to supply a deflection current to the horizontal deflection yoke 7. The + B voltage is further provided as a power supply for a high-voltage generation circuit unit including a high-voltage oscillation drive circuit 208, a high-voltage output circuit 209, and a high-voltage transformer circuit 210.

The operation of the horizontal amplitude adjustment and pincushion distortion correction circuit 239 in the horizontal deflection circuit section is performed by modulating the power supply of the + B voltage E0 to change the horizontal deflection current. This operation will be described. FIG. 15 is a circuit diagram showing details of the horizontal amplitude adjustment and pincushion distortion correction circuit 239 and the horizontal output circuit 206 in the horizontal deflection circuit section.

In FIG. 15, the + B voltage E0 is passed through a portion as a horizontal amplitude adjustment and pincushion distortion correction circuit 239,
It is supplied to the horizontal output circuit 206. Horizontal output circuit 206
Then, the + B voltage E0 passes through the horizontal output coil 344,
Horizontal output transistor 350, damper diode 35
1. Supplied to the site of the retrace resonance capacitor 352. To the collector of the horizontal output transistor 350, a detection transformer 345 for detecting a horizontal deflection current, a horizontal deflection coil 346 (horizontal deflection yoke 207), and an S-shaped correction capacitor 347 are connected. In the horizontal output circuit 206, the horizontal deflection current obtained by the switching operation of the horizontal output transistor 350 by the drive pulse from the horizontal oscillation drive circuit 205 flows through the horizontal deflection coil 346 forming the horizontal deflection yoke 207. Is done.

A horizontal deflection current flows on the primary side of the detection transformer 345, and a signal corresponding to the magnitude of the deflection current is supplied to a portion as a horizontal amplitude adjustment and pincushion distortion correction circuit 239 by the detection transformer 345. Handed over. That is, a rectifying / smoothing circuit including a rectifying diode 348 and a smoothing capacitor 349 is provided on the secondary winding side of the detection transformer 345 as the horizontal amplitude adjustment and pincushion distortion correction circuit 239. Is obtained. This signal voltage is applied to the resistors 235 and 2
Divided by 36 and applied to the inverting input terminal of the inverting comparison amplifier 283. Furthermore, a DC voltage for amplitude adjustment and a parabola voltage synchronized with a vertical cycle for pincushion distortion correction are applied to the non-inverting input terminal of the inverting comparison amplifier 283. The inverting comparison amplifier 283 supplies a signal obtained by comparing the signal voltage divided by the resistors 235 and 236 and the parabola voltage to the pulse width control circuit 353.

The signal pulse-modulated by the pulse width control circuit 353 is connected to a switching element 357 through a resistor 354 and a coupling capacitor 355. The diodes 358 and 359 are diodes for returning energy, and the resistor 356 is a resistor for starting. From the output of the switching element 357, a pulse width modulation voltage obtained by voltage-modulating the + B voltage is obtained, integrated by the horizontal output circuit 206, and the amplitude of the horizontal deflection current is modulated according to the signal voltage.

Next, the high voltage generating circuit will be described. The high-voltage generating circuit section is separated from the horizontal deflection circuit section so as not to be affected by the power supply voltage modulation of the + B voltage. In FIG. 11, the high-voltage generation circuit section is constituted by a separately excited current resonance type converter, and a switching section 242 is provided.
Switching element Q3 so that the two switching elements Q3 and Q4 constituting
Of the switching element Q4 and the source of the switching element Q4,
The resonance capacitor 245 and the high-voltage transformer 247 are connected in series. To the switching elements Q3 and Q4, rectangular drive pulses having mutually different polarities for alternately turning on and off are supplied from the high-voltage oscillation drive circuit 208 every half cycle.

The switching operation of the high-voltage generating circuit having the above configuration is as follows. When power is supplied from the + B voltage to the high-voltage oscillation drive circuit 208 through the resistor 241, a positive drive pulse is supplied to the switching element Q3 by the high-voltage oscillation drive circuit 208, and the switching element Q3 is turned on. Then, the resonance capacitor 245 and one of the high-voltage transformers 247 are connected through the switching element Q3.
A positive resonance current is supplied to the next winding 248. Next, the high-voltage oscillation drive circuit 208 supplies a negative drive pulse to the switching element Q3, and conversely, if a positive drive pulse is supplied to the switching element Q4, the switching element Q3 turns off rapidly and , Switching element Q
4 turns on. As a result, a negative resonance current is supplied to the resonance capacitor 245 and the primary winding 248 of the high-voltage transformer 247 through the switching element Q4. By repeating this operation, the high-voltage transformer 247 is excited by the series resonance current, and an alternating output voltage is extracted from the high-voltage windings 250 to 258 wound on the secondary side of the high-voltage transformer 247.

The high voltage transformer 247 includes the primary winding 248 to which the exciting current is supplied as described above. A high-voltage winding green 250 to 25 for obtaining a high-voltage output voltage EHT for supplying an anode voltage to a cathode ray tube (CRT) as a secondary winding.
8 and a secondary winding 249 for obtaining a voltage E1 used as a detection voltage of the protection circuit. The high-voltage windings 250 to 258 are configured to perform full-wave rectification on positive and negative alternating voltages.
And rectifier diodes 265 to 268 are connected in series,
The high-voltage windings 250 to 253 are connected to the high-voltage windings 255 to 258 after rectifier diodes 260 to 264 are connected in series so as to have the opposite polarity to the high-voltage windings 255 to 258. In the connection portion between the high-voltage winding 253 and the high-voltage winding 255,
A high-voltage winding 254 having one open end is wound thereon, and a smoothing capacitor is equivalently provided, and rectified voltages obtained from the high-voltage windings 250 to 253 and 255 to 258 are stacked in series to form a smoothing capacitor 270. Is configured to obtain a high output voltage EHT at one end.

The constant voltage of the high voltage output voltage EHT for supplying the anode voltage of the cathode ray tube (CRT) obtained from the high voltage windings 250 to 258 is the same as in the case of the + B voltage described above. Done.

For example, it is assumed that the brightness of the image displayed on the cathode ray tube increases and, as a result, the high-voltage load fluctuates so as to increase. At this time, since the high-voltage output voltage EHT fluctuates so as to decrease, the voltage fluctuation is taken out by a voltage detection circuit composed of the resistors 271 and 272, and a control signal obtained by the control circuit 273 is sent to the high-voltage oscillation drive circuit 208. Control is performed such that the operating frequency of the drive pulse output from the high-voltage oscillation drive circuit 208 decreases in accordance with this voltage. As a result, assuming that the switching frequency of the switching elements Q3 and Q4 is fsw1, this switching frequency fs
w1 decreases. Conversely, if the brightness of the image displayed on the cathode ray tube decreases, and as a result, the high voltage load fluctuates so as to decrease, the high voltage output voltage EHT fluctuates to increase. Is sent to the high-voltage oscillation driving circuit 208, and the high-voltage oscillation driving circuit 2
08 is controlled so as to increase the operating frequency of the driving pulse output. As a result, switching element Q3,
The switching frequency fsw1 of Q4 increases.

In such a high voltage generation circuit section, assuming that the resonance frequency of a series resonance circuit composed of the series resonance capacitor 245, the choke coil 246 and the primary winding 248 of the high voltage transformer 247 is f01, the resonance frequency f01
The switching frequency fsw1 of the switching circuit constituted by the half-bridge converter is set higher than that of the half-bridge converter. Therefore, in the case described above, when the brightness of the image displayed on the cathode ray tube increases and the high-voltage load increases,
Since the high-voltage output voltage EHT fluctuates to decrease, the switching frequency fsw1 is controlled to decrease. At this time, the switching frequency fsw1 approaches the resonance frequency f01 of the series resonance circuit,
As a result, the excitation current flowing through the primary winding 248 increases, and the constant voltage is measured. Conversely, when the brightness of the image displayed on the cathode ray tube decreases and as a result the high-voltage load fluctuates so as to decrease, the high-voltage output voltage EH
Since T fluctuates so as to increase, the switching frequency fsw1 is controlled to increase, and the switching frequency fsw is changed with respect to the resonance frequency f01 of the series resonance circuit.
1 are separated, and as a result, the exciting current flowing through the primary winding 248 is suppressed, so that a constant voltage is achieved.

[0031]

The conventional switching power supply device is configured as described above, for example. However, there is a point to be improved in terms of economical efficiency and effective utilization of energy resources. The first is the power loss of the switching unit, the second is the power loss associated with the amplitude adjustment pincushion distortion correction in the horizontal deflection circuit unit, and the third is the conversion efficiency of the switching converter output transformer, ie, the converter transformer 221 and the high-voltage transformer 247. .

The three problems will be described. First, this switching power supply device includes a power supply circuit unit having a function of providing a constant voltage output voltage and a high-frequency deflection circuit unit. It has a circuit configuration including a high-voltage generation circuit section separately. Therefore, the switching circuit system of the power supply circuit section (the oscillation drive circuit 202 and the converter circuit 203)
And the switching circuit system (the high-voltage oscillation drive circuit 208 and the high-voltage output circuit 209) of the high-voltage generation circuit section must be provided respectively. Although it is very advantageous in terms of characteristics to provide the switching circuit system of the high-voltage generation circuit unit separately from the power supply circuit unit, as a result, the disadvantage that the circuit configuration is complicated and the extra switching circuit system is required. There is a problem that power loss increases.

Secondly, as described above, in the case of the conventional high-definition deflection high-voltage device for displaying high resolution, the high-voltage circuit is formed as a separate circuit while avoiding the influence on the deflection circuit. Since the amplitude adjustment and the pincushion distortion correction operation are performed by the power supply modulation method, power loss results.

Third, the power supply circuit section has an insulation type converter transformer for insulation from the earth ground, and the high voltage generation circuit section has a non-insulation type high voltage transformer such as a flyback transformer. Because
The converter transformer 221 and the high-voltage transformer 247 must be provided in a double configuration. As a result, a DC / DC conversion efficiency is poor in a configuration in which a high-voltage output voltage is extracted using a switching unit that performs a switching operation using a rectified and smoothed voltage obtained from a commercial AC power supply as an operation power supply, and there is a problem in saving power. .

[0035]

SUMMARY OF THE INVENTION The switching power supply of the present invention solves the above-mentioned problems and reduces the power loss of the switching power supply and improves the conversion efficiency. In other words, the switching output circuit that performs the switching operation is operated with low loss, and the control means that uses the switching frequency control connected to the switching output circuit that performs the switching operation and the inductance control that can perform the operation with low loss is adopted. It is an object of the present invention to provide a switching power supply device that is practically suitable by simultaneously configuring the high-voltage generation circuit section and the horizontal deflection circuit to adjust the horizontal amplitude and correct the pincushion distortion.

To achieve this object, a switching power supply according to the present invention comprises a rectifying / smoothing means for generating a rectified / smoothed voltage across a smoothing capacitor using a rectified current obtained by rectifying a commercial AC power supply as a charging current; A switching means for performing a switching operation using the rectified smoothed voltage as an operating power supply; an oscillation driving means for controlling a switching frequency connected to the switching means for performing the switching operation; and a resonance in a primary winding of a converter transformer formed of an insulation type. A switching converter to which a capacitor is connected so that the switching operation of the switching means is of a resonance type is provided. A switching frequency control means for winding a high-voltage winding as a secondary winding green of the converter transformer and controlling the switching frequency using a control signal obtained from an output of a high-voltage rectifier circuit connected to the high-voltage winding. And an inductance control means for connecting a saturable reactor to another secondary winding of the converter transformer, and controlling the inductance of the saturable reactor. Amplitude adjustment and pincushion distortion in a horizontal deflection circuit using the saturable reactor. The switching power supply circuit is configured to include an adjustment / correction unit for performing the correction.

In the present invention having such a configuration, the switching output waveforms are compared in order to reduce the power loss of the switching power supply circuit that drives a plurality of constant-voltage outputs that require a high-precision load characteristic. Means to form a resonant switching circuit with characteristics that are smooth, low in switching noise and low in switching loss, and control high voltage output by frequency control to supply the anode voltage of the cathode ray tube, and constant voltage by temporary loss A circuit configuration with low loss and high efficiency by adopting a control means based on inductance control having a feature of being able to perform a control operation and comprising means for performing amplitude adjustment and pincushion distortion correction in a horizontal deflection circuit. Is possible.

[0038]

Embodiments of the present invention will be described below with reference to the drawings. Note that, in each drawing, the same reference numeral is given to a component having the same function. In the description, first, a basic block configuration of a switching power supply device according to an embodiment of the present invention will be described, and then, a specific circuit configuration according to various embodiments will be described.

<Basic Block Configuration> FIG. 1 shows a basic block configuration as an embodiment of the switching power supply of the present invention. The switching power supply of the embodiment is suitable as a switching power supply such as a television receiver or a monitor display using a cathode ray tube, and as shown in FIG. As a circuit system, a power supply circuit section, a horizontal deflection circuit section, and a high voltage generation circuit section are provided roughly.

The power supply circuit section includes an AC rectifying / smoothing circuit 1, an oscillation driving circuit 2, a converter circuit 3, and a converter transformer circuit 4. The horizontal deflection driving circuit 5 and the horizontal output circuit 6 are provided as a horizontal deflection circuit for the horizontal deflection yoke 7. A part of the converter transformer circuit 4 is formed as a circuit having the functions of the horizontal amplitude adjustment and pincushion distortion correction circuit 239 shown in FIG. In the high-voltage generating circuit section for the cathode ray tube 11, a part of the converter transformer circuit 4 has the functions of the high-voltage output circuit 209 and the high-voltage transformer 210 shown in FIG. That is, as can be seen from a comparison between FIG. 10 and FIG. 1, in the case of the present embodiment, when viewed from a block, an independent high-voltage generation circuit is not formed, and the high-voltage generation circuit is included in the converter transformer circuit 4 in the power supply circuit. It has a function as a part.
The function as the horizontal amplitude adjustment and pincushion distortion correction circuit is also realized by a part of the converter transformer circuit 4.

The AC rectifying / smoothing circuit 1 supplies a rectified current obtained by rectifying a commercial AC power supply to a smoothing capacitor as a charging current, and generates a rectified smoothed voltage across the smoothing capacitor. Using the rectified and smoothed voltage obtained from the AC rectifying and smoothing circuit 1 as an operating power supply, the converter circuit 3 is caused to perform a switching operation by using a driving pulse obtained from the oscillation driving circuit 2. The converter transformer in the converter transformer circuit 4 is excited by the switching operation of the converter circuit 3, and an output voltage is extracted from the converter transformer. As the output voltage to be taken out, in addition to the + B voltage used as a power supply for the horizontal deflection circuit section,
There is also a high voltage supplied to the anode of the cathode ray tube 11.
That is, the converter transformer also has a function as a transformer for generating a high voltage.

The output voltage from the converter transformer circuit 4 supplied as a power source for the horizontal deflection circuit is supplied to a horizontal output circuit 6. A driving pulse obtained from the horizontal oscillation driving circuit 5 is supplied to the horizontal output circuit 6. The horizontal output circuit 6 performs a switching operation using the driving pulse, and supplies a deflection current to the horizontal deflection yoke 7.

<First Embodiment> FIG. 2 shows a circuit configuration of a first embodiment corresponding to the configuration of FIG.
This will be described below.

In the AC rectifying / smoothing circuit 1, a bridge rectifying diode 13 is provided for an AC power supply 12 to perform a full-wave rectifying operation, and a rectifying / smoothing voltage is obtained by a smoothing capacitor 14. Rectified smoothing voltage is resistor 15
Is supplied to the oscillation drive circuit 2 through the inverter circuit 3 and to the converter circuit 3.

In the converter circuit 3, for example, a power MO
Using a switching element such as an SFET, two switching elements Q1,
Q2 forms a half bridge circuit. That is, the source of the switching element Q1 and the drain of the switching element Q2 are connected, and the resonance capacitor 19 and the choke coil 20 and the insulation type converter transformer 1
Forty primary windings 22 are connected in series. Damper diodes 17, 18 are connected to the switching elements Q1, Q2. A is connected to the drain of the switching element Q1.
It is connected so that a rectified and smoothed voltage from C rectifying and smoothing circuit 1 is supplied. Power is supplied to the oscillation drive circuit 2 from the rectified and smoothed voltage from the AC rectification and smoothing circuit 1 through the resistor 15. The oscillation drive circuit 2 is connected so that rectangular drive pulses having different polarities for alternately turning on and off every half cycle are supplied to the gates of the switching elements Q1 and Q2. An excitation type current resonance type converter circuit is configured.

The basic operation of the current resonance type converter circuit constituted by the half bridge circuit is the same as that described above with reference to FIG. Therefore, as the switching operation, first, when the commercial AC power supply 12 is turned on, a positive drive pulse is supplied from the oscillation drive circuit 2 to the re-switching element Q1 to be turned on. Then, the primary winding 2 wound on the primary side of the resonance capacitor 19, the choke coil 20, and the converter transformer 140 through the switching element Q1.
2 is supplied with a positive resonance current. Next, a negative drive pulse is supplied to the switching element Q1, and conversely, a positive drive pulse is supplied to the switching element Q2, and the switching element Q1 is rapidly turned off and the switching element Q2 is turned on. . As a result, the resonance capacitor 19 and the choke coil 20 pass through the switching element Q2.
A negative resonance current is supplied to the primary winding 22 of the converter transformer 140. By repeating this operation, the reconverter transformer 140 is excited by the series resonance current, and an alternating output voltage is obtained from each winding wound on the secondary side of the converter transformer 140.

The converter transformer 140 is of an insulation type, and has a primary winding 22 on the primary side to which an exciting current is supplied as described above. On the secondary side, high-voltage windings 50 to 58 having rectification circuits for obtaining a high-voltage output voltage EHT for supplying an anode voltage of the cathode ray tube (CRT) 11 as secondary windings, and mainly a horizontal deflection circuit Secondary winding 23 to obtain + B voltage and other voltages used as the power supply voltage of
26 and 49. The secondary winding 23 has
A saturable reactor 86 for performing amplitude adjustment and pincushion distortion correction in the horizontal deflection circuit is connected.

The high-voltage windings 50 to 58 are connected to the high-voltage winding 5 so that full-wave rectification is performed for each of the positive and negative alternating voltages.
5 to 58 and rectifier diodes 65 to 68 are connected in series, and the high voltage windings 50 to 53 are connected to the high voltage windings 55 to 58.
After the rectifier diodes 60 to 64 are connected in series so as to have the opposite polarity, the rectifier diodes 60 to 64 are connected to the high voltage windings 55 to 58.
A high-voltage winding 54 having one open end is wound around a connection portion between the high-voltage winding 53 and the high-voltage winding 55 in order to provide a smoothing capacitor equivalently using stray capacitance.
Using the equivalently provided capacitors, the rectified voltages obtained from the high-voltage windings 50 to 53 and the high-voltage windings 55 to 58 are stacked in series for each of the positive and negative alternating voltages. At one end, a high output voltage EHT is provided.

The constant voltage of the high output voltage EHT obtained from the high voltage windings 50 to 58 is performed as follows. For example,
When the input voltage value of the commercial AC power supply 12 decreases, or the brightness of the image displayed on the cathode ray tube 11 increases,
As a result, when the high-voltage load fluctuates so as to increase, the high-voltage output voltage EHT fluctuates so as to decrease. This voltage fluctuation is taken out by a voltage detection circuit composed of resistors 71 and 72, and a control signal obtained by a control circuit 73 is supplied to the oscillation drive circuit 2 through a photocoupler 38 for insulating a constant voltage control system. The oscillation drive circuit 2 responds to this control signal.
The control is performed so that the operating frequency of the driving pulse output from the driving pulse is reduced. As a result, assuming that the switching frequency of the switching elements Q1 and Q2 constituting the switching unit 16 is fsw2, the switching frequency fsw2 decreases. Conversely, when the input voltage of the commercial AC power supply 12 increases, or when the brightness of the image displayed on the cathode ray tube decreases, and as a result, the high-voltage load fluctuates so as to decrease, the high-voltage output voltage EHT is changed. It fluctuates to rise. This voltage fluctuation is similarly extracted by a voltage detection circuit composed of resistors 71 and 72, and the control circuit 73 supplies a control signal corresponding to the voltage fluctuation to the oscillation drive circuit 2 through the photocoupler 38. Then, control is performed so that the operating frequency of the drive pulse output from the oscillation drive circuit 2 increases according to the control signal. As a result, switching element Q1,
The switching frequency fsw2 of Q2 increases.

In this power supply circuit, the resonance capacitor 19,
The switching frequency fsw2 of the switching unit 16 composed of a half-bridge type converter is set higher than the resonance frequency of the series resonant circuit composed of the choke coil 20 and the primary winding 22 of the converter transformer. Therefore, in the case described above, when the luminance of the image displayed on the cathode ray tube 11 increases and the high-voltage load increases, the high-voltage output voltage EHT fluctuates so as to decrease, so that the switching frequency fsw2 is controlled to decrease. However, at this time, if the resonance frequency of the series resonance circuit is f02, the switching frequency fsw
2 approaches, and as a result, the excitation current flowing through the primary winding 22 increases, and the constant voltage is measured. Conversely, when the brightness of the image displayed on the cathode ray tube 11 decreases and the high-voltage load fluctuates to decrease, the high-voltage output voltage EHT fluctuates to increase, and the switching frequency fsw2 increases. And the switching frequency fsw2 is separated from the resonance frequency f02 of the series resonance circuit. As a result, the exciting current flowing through the primary winding 22 is suppressed, and the constant voltage is measured. become.

The converter transformer 140 is provided with a secondary winding 49 for obtaining a voltage E1 used as a detection voltage of the protection circuit. The half-wave rectifying and smoothing circuit by the smoothing capacitor 69 converts the voltage to a DC voltage,
1 is taken out.

A rectifying and smoothing circuit for extracting a DC voltage from the alternating output voltage is also connected to each of the secondary windings 23, 24, 25, and 26 of the converter transformer 140. That is, a diode constituting the rectifier circuit 27 and the smoothing capacitors 30 and 31 are connected to the secondary winding 23 as shown in the figure, and the + B voltage E0 is extracted by the double voltage half-wave rectification method. Diodes constituting the rectifier circuit 28 and smoothing capacitors 32, 3 are provided for the secondary windings 24, 25.
3 are connected as shown, and a positive voltage E3 and a negative voltage E4 are taken out. For the secondary winding 26, a voltage E2 by a half-wave rectification method is extracted by a rectifier diode 29 and a smoothing capacitor.

The + B voltage E0 taken out from the secondary winding 23 of the converter transformer 140 is a power supply voltage mainly used in the horizontal deflection circuit section. Voltage modulation for amplitude adjustment and pincushion distortion correction is performed.

The voltage modulation of the + B voltage E0 is performed as follows. A saturable reactor 86 is connected in series as means for performing amplitude adjustment and pincushion distortion correction in the horizontal deflection circuit to the secondary winding 23 of the converter transformer 140, and a method for controlling the inductance of this saturable reactor is described. I am taking. This saturable reactor is, for example, an orthogonal saturable reactor having a control winding NC and a control winding NR as shown in FIG. The controlled winding NR is connected in series to the secondary winding 23, and is configured such that the current flowing through the control winding NC is controlled by a control signal.

Secondary winding 23 of converter transformer 140
Is supplied to the horizontal output circuit 6. In the horizontal output circuit 6, the + B voltage E0 is supplied to the horizontal output transistor 150,
Damper diode 151, retrace resonance capacitor 15
2 to the site. Horizontal output transistor 15
The zero collector is connected to a detection transformer 145 for detecting a horizontal deflection current, a horizontal deflection coil 146 (horizontal deflection yoke 7), and an S-shaped correction capacitor 147. In the horizontal output circuit 6, the horizontal deflection current obtained by the switching operation of the horizontal output transistor 150 by the driving pulse from the horizontal oscillation drive circuit 5 is:
It is made to flow to the horizontal deflection coil 146 constituting the horizontal deflection yoke 7.

A horizontal deflection current flows on the primary side of the detection transformer 145, and a signal corresponding to the magnitude of the deflection current by the detection transformer 145 is used to perform horizontal amplitude adjustment and pincushion distortion correction. Passed to.
That is, a rectifying / smoothing circuit including a rectifying diode 148 and a smoothing capacitor 149 is provided on the secondary winding side of the detection transformer 145, so that a signal corresponding to the magnitude of the deflection current is obtained. This signal voltage is applied to the resistors 35 and 36.
And is applied to the inverting input terminal of the inverting comparison amplifier 83. Further, a DC voltage for amplitude adjustment and a parabola voltage synchronized with a vertical cycle for pincushion distortion correction are applied to the non-inverting input terminal of the inverting comparison amplifier 83. The inverting comparison amplifier 83 applies a signal obtained by comparing the signal voltage divided by the resistors 35 and 36 and the parabola voltage to the base of the control transistor 85 via the resistor 84. The collector of the control transistor 85 is connected to the control winding NC of the saturable reactor 86.
And the emitter is grounded. That is, the control transistor 85 has a function of controlling the inductance of the saturable reactor 86 by controlling the current amount of the control winding NC according to the base current from the inverting comparison amplifier 83.

The operation of pincushion distortion correction will be described by taking as an example a case where the parabola correction voltage is increased to increase the pincushion distortion correction. When the amplitude of the parabolic component of the correction signal applied to the non-inverting input terminal voltage of the inverting comparison amplifier 83 increases, the output of the inversion comparison amplifier 83 increases according to the parabolic waveform,
The collector current of the control transistor 85 increases. As described above, the collector of the control transistor 85 is connected to the control winding NC of the saturable reactor 86, and the emitter is grounded. An output voltage E3 is applied to the other end of the control winding NC as a voltage source. Therefore, when the collector current of the control transistor 85 increases, the control winding NC
Increases, and the inductance of the controlled winding NR of the saturable reactor 86 acts to decrease. As a result, the voltage drop due to the inductance decreases, and the + B voltage E0 is modulated by the inductance control so that the parabola voltage increases. For the amplitude adjustment, + B voltage E0 is controlled by the same operation. Also, the AC power supply 12
The + B voltage E0 is not affected by fluctuations in the AC input voltage or high-voltage load fluctuations. In this way, +
The B voltage E0 is modulated into a voltage corresponding to the horizontal amplitude adjustment of the horizontal deflection circuit unit and the pincushion distortion correction signal.
Is supplied with a desired current to perform amplitude modulation and pincushion distortion correction.

As described above, according to the first embodiment, the high-voltage windings 50 to 58 are provided as the secondary winding of the converter transformer 140, and the high-voltage output voltage EHT is obtained. The switching frequency of the switching unit 16 is controlled using a control signal obtained from the output of the high-voltage rectifier circuit connected to the high-voltage windings 50 to 58. Further, a saturable reactor 86 is connected to the secondary winding 23 of the converter transformer 140, and the inductance of the saturable reactor 86 is controlled to perform amplitude adjustment and pincushion distortion correction in the horizontal deflection circuit section. As a result, the + B voltage E0 and the other voltage E
1 to E4 and a high-voltage output voltage EHT, that is, the high-voltage generation circuit is integrated with the power supply circuit. Further, the amplitude adjustment and the pincushion distortion correction circuit can be integrated. As a result, the loss of the switching circuit can be reduced, and the conversion efficiency can be significantly improved by directly supplying the high-voltage output voltage EHT from the converter transformer 140. Of course, the circuit configuration can be simplified and downsized.

<Second Embodiment> A second embodiment will be described with reference to FIG. The description of the same parts as those in FIG. 2 will be omitted.

In the embodiment shown in FIG. 4, the converter transformer in the converter transformer circuit 4 comprises a plurality of insulated converter transformers 141 and 142.
The first converter transformer 141 has a primary winding 22 to which an exciting current is supplied, and as a secondary winding, for example, obtains a high output voltage EHT as an anode voltage of the cathode ray tube 11 (CRT). It comprises high voltage windings 50 to 58 and secondary windings 24, 25, 26, 49 for obtaining other voltages. The second converter transformer 142 includes a primary winding 106 to which an exciting current is supplied and a secondary winding 23 for obtaining a + B voltage E0 used as a power supply voltage of the horizontal deflection circuit.
And the second converter transformer 142
The secondary winding 23 is connected to a saturable reactor 86 for performing amplitude adjustment and pincushion distortion correction.

As shown in the figure, a resonance capacitor 19 is provided at the contact between the source of the switching element Q1 and the drain of the switching element Q2 so that the two switching elements Q1 and Q2 forming the switching section 16 form a half bridge circuit. Are connected in series. One end of a primary winding 22 of the first converter transformer 141 is connected to the other end of the resonance capacitor through a choke coil 20. The other end of the primary winding 22 is grounded. Further, one end of the primary winding 106 of the second converter transformer 142 is connected to the resonance capacitor 19 through the choke coil 143, and the other end of the primary winding 106 is grounded. Therefore, the choke coil 20 and the first
Primary winding 22 of converter transformer 141, and choke coil 143 and second converter transformer 142
Are configured to form a parallel circuit.

As the switching operation of the power supply circuit having such a configuration, first, when the commercial AC power supply 12 is turned on, a positive drive pulse is supplied from the oscillation drive circuit 2 to the switching element Q1 to be turned on. Then, the resonance capacitor 19 and the primary windings 22 and 1 of the first and second converter transformers 141 and 142 are passed through the switching element Q1.
06 is supplied with a positive resonance current corresponding to the inductance value of the combined inductor forming the series resonance circuit.
Next, a negative driving pulse is supplied to the switching element Q1, and a positive driving pulse is supplied to the switching element Q2, so that the switching element Q1 is turned off and the switching element Q2 is turned off.
Turns on. As a result, contrary to the above, the primary windings 22 and 1 of the resonance capacitor 19 and the first and second converter transformers 141 and 142 pass through the switching element Q2.
06 is supplied with a negative resonance current. By repeating this operation, the first and second converter transformers 141 and 142 are excited by the resonance current, and the alternating output voltages are respectively extracted from the secondary windings.

The high-voltage output voltage EHT taken out from the high-voltage windings 50 to 58 of the first converter transformer 141 is made constant in the following manner. For example, when the commercial AC voltage decreases, or when the brightness of the image displayed on the cathode ray tube increases, and as a result, the high-voltage load changes to increase, the high-voltage output voltage EHT changes to decrease. I do. This voltage fluctuation is taken out by a voltage detection circuit constituted by resistors 71 and 72, and a control signal obtained by a control circuit 73 is used by a photocoupler 38 for insulating a constant voltage control system.
Is supplied to the oscillation drive circuit 2 through the control circuit and is controlled so that the operating frequency of the drive pulse output from the oscillation drive circuit 2 is reduced according to the voltage. As a result, assuming that the switching frequency of the switching elements Q1 and Q2 is fsw3, the switching frequency fsw3 decreases. Conversely, when the commercial AC input voltage increases, or when the brightness of the image displayed on the cathode ray tube decreases, and as a result, the high-voltage load fluctuates to decrease, the high-voltage output voltage E
HT fluctuates ascending. Then, as described above, the control signal is sent to the oscillation drive circuit 2 through the photocoupler 38, and is controlled so that the operating frequency of the drive pulse output from the oscillation drive circuit 2 increases according to the voltage. As a result, the switching frequency fsw3 of the switching elements Q1, Q2 increases.

In this power supply circuit, the switching frequency fsw3 of the switching section 16 constituted by a half-bridge type converter depends on the resonance capacitor 19, the choke coil 20, the primary winding 22 of the first converter transformer 141, and the choke coil. 143 and the primary winding 106 of the second converter transformer 142 are set to be always higher than the resonance frequency f03 of the resonance circuit. Therefore, if the brightness of the image displayed on the cathode ray tube 11 increases, and as a result, the high-voltage load fluctuates to increase, the high-voltage output voltage EHT fluctuates to decrease, so that the switching frequency fsw3 decreases. And the switching frequency fsw3 approaches the resonance frequency f03 of the series resonance circuit. As a result, the exciting current flowing through the primary winding 22 increases,
A constant voltage will be measured. Conversely, if the brightness of the image displayed on the cathode ray tube 11 decreases, and as a result, the high-voltage load fluctuates to decrease, the high-voltage output voltage EHT fluctuates to increase, so that the switching frequency fs
Control is performed so that w3 increases. Therefore, the switching frequency fsw3 is higher than the resonance frequency f03 of the resonance circuit.
Are separated, and as a result, the excitation current flowing through the primary winding 22 is suppressed, so that a constant voltage is measured.

Secondary winding 23 of converter transformer 142
The voltage modulation of the + B voltage E0 taken out of is performed as follows. Secondary winding 23 of this converter transformer
Is connected to a saturable reactor 86 in series as a means for performing amplitude adjustment and pincushion distortion correction in the horizontal deflection circuit unit, and adopts a method of controlling the inductance of this saturable reactor. This saturable reactor includes, for example, a control winding NC and a controlled winding N as shown in FIG.
And an orthogonal saturable reactor having R. The controlled winding NR is connected in series to the secondary winding 23, and is configured such that the current flowing through the control winding NC is controlled by the control transistor 85.

The configuration for controlling the inductance of the saturable reactor 86 is the same as that of the first embodiment. That is, the collector of the horizontal output transistor 150 has a detection transformer 14 for detecting the horizontal deflection current.
The secondary winding of the detection transformer 145 is provided with a rectifying / smoothing circuit including a rectifying diode 148 and a smoothing capacitor 149, so that a signal corresponding to the magnitude of the deflection current is obtained. This signal voltage is divided by the resistors 35 and 36 and applied to the inverting input terminal of the inverting comparison amplifier 83. Further, a DC voltage for amplitude adjustment and a parabola voltage synchronized with a vertical cycle for pincushion distortion correction are applied to the non-inverting input terminal of the inverting comparison amplifier 83. The output of the inverting comparison amplifier 83 is connected through a resistor 84 to the base of a control transistor 85 that controls the inductance of a saturable reactor 86. Then, as described in the description of the first embodiment, the collector current of the control transistor 85 increases or decreases according to the output of the inverting comparison amplifier 83,
The control current of the control winding NC increases or decreases. This increases or decreases the inductance of the control winding NR of the saturable reactor, and as a result, the + B voltage E0 is modulated by the inductance control.

Such a second embodiment is similar to the first embodiment.
The same effect as that of the embodiment can be realized by a plurality of converter transformers. That is, the primary winding 22 of the first converter transformer 141 and the series resonance capacitor 1
9 and a series resonance circuit provided to make the switching operation of the switching unit 16 a current resonance type, and the primary winding 10 of the second converter transformer 142.
6 and a series resonance capacitor 19 are connected in parallel with a series resonance circuit provided so that the switching operation of the switching unit 16 is of the current resonance type. The saturable reactor 86 is connected to the second converter transformer 2. Connected to the next winding. Then, by controlling the inductance of the saturable reactor 86, amplitude adjustment and pincushion distortion correction in the horizontal deflection circuit section are performed. Thus, the same effects as those of the first embodiment can be obtained, and the degree of freedom and the productivity of the optimum design of the converter transformer can be improved.

<Third Embodiment> A third embodiment of the present invention will be described with reference to FIG. The description of the same parts as those in FIG. 2 will be omitted.

In the case of this embodiment, the oscillation driving circuit 2
Are configured using a self-oscillation type. In FIG.
The switching unit 16 is configured using, for example, bipolar transistors as the switching elements Q1 and Q2. The resonance capacitor 19 is connected to the contact point between the emitter of the switching element Q1 and the collector of the switching element Q2.
D, choke coil 20 and converter transformer 14
0 shows an example of a self-excited current resonance converter in which a primary winding 22 is connected in series to form a half-bridge type series resonance circuit.

As shown in FIG. 6, the drive transformer 82 is configured by winding drive windings NB1 and NB2, an exciting winding ND, and a control winding NC for controlling the inductance of each of these windings. Also, for example, an orthogonal saturable reactor is used. However, it may be constituted by an EI type or the like. One drive winding NB1 of the drive transformer 82
Is connected so that the resistor 80 and the resonance capacitor 78 form a series resonance circuit, is connected to the base of the switching element Q1, and has the other end connected to the switching element Q1.
Connected to one emitter. The drive winding NB2 has one end connected to form a series resonance circuit with the resistor 81 and the resonance capacitor 79 so as to have the opposite polarity to the drive winding NB1, and is connected to the base of the switching element Q2. Is grounded.

The re-switching elements Q1 and Q2 are driven by the oscillation driving circuit 2 configured as described above. That is, the switching element Q is determined by the resonance frequency of each series resonance circuit.
1 and Q2 are turned on / off. The switching operation frequency of the switching elements Q1 and Q2 is
B1 or NB2 inductance and resonance capacitor 78
Or 79 is determined by the resonance frequency of the series resonance circuit, and the driving winding NB1 is controlled so as to perform constant voltage control of the output voltage.
And NB2 to form a self-excited frequency control circuit.

In the switching operation of the current resonance type power supply circuit having the above configuration, first, when the commercial AC power supply 12 is turned on, a starting current is supplied to the base of the switching element Q1 through the resistor 77 for starting. Now
When the switching element Q1 is turned on,
Using the rectified output voltage as a DC power supply, the switching element Q1
Through the resonance capacitor 19, the exciting winding ND, the choke coil 20, and the primary winding 22 of the converter transformer 140. When the resonance current becomes zero, a positive pulse is generated in the drive winding NB2 of the drive transformer 82 so as to turn on the switching element Q2. Conversely, the switching element Q1 is provided in the drive winding NB1 of the drive transformer 82. A negative pulse is generated to turn off. Therefore, the switching element Q1 turns off rapidly and the switching element Q2 turns on. As a result, a negative resonance current flows through the switching element Q2. As described above, the switching elements Q1 and Q2 are alternately turned on and off alternately, so that an exciting current is supplied to the primary winding 22 of the converter transformer 140 and an alternating output is obtained on the secondary winding.

The converter transformer 140 has a primary winding 2
2, a high-voltage winding 89 for obtaining a high-voltage output voltage, and secondary windings 23 to 26 and 49 for obtaining other voltages. A saturable reactor 86 is connected as a means for performing amplitude adjustment and pincushion distortion correction. The high-voltage winding 89 includes, for example, rectifier diodes 90 to 97 and a smoothing capacitor 98.
To a high voltage output voltage EH is connected to a multiple voltage rectifier circuit such as a Cockcroft-Walton circuit composed of
It is configured to obtain T.

The constant voltage control of the high output voltage EHT is performed as follows. High voltage winding 89 and diodes 90-9
Assuming that the high-voltage output voltage EHT extracted from the eight-fold Cockcroft-Walton circuit constituted by the N.7 and smoothing capacitors 98 to 104 fluctuates so as to increase, this voltage fluctuation is caused by the voltage detection constituted by the resistors 71 and 72. The control signal obtained by the control circuit 73 after detection by the circuit is controlled so that the collector current of the control transistor 87 increases. One end of the control winding NC of the drive transformer 82 is connected to the collector of the transistor 87, and the other end is connected to the voltage source 88. Therefore, the collector current of the transistor 87 serves as the control current, and the control winding N of the drive transformer 82 composed of a saturable reactor is used.
C, the control current is controlled to increase, and the drive transformer 82 tends to saturate, and the drive windings NB1, NB
2 acts to reduce the inductance. As a result, the oscillation frequency of the self-excited oscillation circuit increases, and if the switching frequency at this time is fsw4, the switching frequency fsw4 is controlled to increase. Here, if the resonance frequency formed by the resonance capacitor 19, the choke coil 20, and the primary winding 22 of the converter transformer 140 is f04, the switching frequency fsw4 is higher than the resonance frequency f04 in the region similar to the above-described circuit. Therefore, when the switching frequency is increased, the switching frequency becomes farther than the resonance frequency fsw4, the exciting current supplied to the primary winding 22 is suppressed, and the secondary winding 8
9 is made constant.

Secondary winding 23 of converter transformer 140
The horizontal amplitude adjustment and the pincushion distortion correction of the + B voltage E0 taken out of the second embodiment are performed in the same manner as in the above-described first and second embodiments. That is, the saturable reactor 86 is connected to the secondary winding 23. And this saturable reactor 86
Is composed of a control winding NC and a control winding NR, a controlled winding NR is connected in series to the secondary winding 23,
The inductance of the controlled winding NR is controlled by supplying a control current according to the amplitude adjustment and the pincushion distortion correction signal to the control winding NC, and the + B voltage corresponds to the horizontal amplitude adjustment of the horizontal deflection circuit and the pincushion distortion correction signal. The voltage is then modulated to supply a desired current to the horizontal deflection yoke to perform amplitude modulation and pincushion distortion correction.

In the case of the third embodiment, the same effect as that of the first embodiment can be obtained, and the drive transformer 8 composed of a saturable reactor can be obtained.
2, the circuit configuration can be simplified. The rectifier circuit connected to the high-voltage winding 89 of the converter transformer 140 is provided with a multiple voltage rectification output circuit, so that a high voltage can be obtained. The degree of freedom in optimal design can be improved.

<Fourth Embodiment> A fourth embodiment will be described with reference to FIG. In this example, the switching unit 16 is formed of one switching element Q5, and the resonance capacitor 19 and the dambar diode 17 are connected in parallel to the switching element Q5. The rectified output voltage of the commercial AC power supply 12 is supplied to one end of the primary winding 22 of the converter transformer 140 through the choke coil 20, and the other end of the primary winding 22 of the converter transformer 140 is connected to the switching element Q 5 of the switching unit 16. Connected to collector. The resistor 15 supplies power to the oscillation drive circuit 2,
A drive pulse is sent from the oscillation drive circuit 2 to the base of the switching element Q5 of the switching unit 16, and the switching element Q5 is turned on and off, so that a resonance voltage is generated at the collector of the switching element Q5. A resonance current is supplied to the primary winding 22. Configuration of the site where high voltage output voltage EHT is generated, and + B
The configuration for adjusting the amplitude of the voltage E0 and controlling the pincushion distortion correction is the same as the example shown in FIG.

That is, in the fourth embodiment, a parallel resonance circuit is formed in the converter circuit 3 so that the same circuit operation as in the above embodiments can be performed by the voltage resonance switching converter circuit. It will be realized.

<Modifications> Various examples of the embodiments have been described above. However, the present invention is not limited to the configuration of each of the above embodiments, and the method of the resonance type converter is appropriately changed. It may be configured in such a manner. The choke coil 20 (143) connected in series to the converter transformer 140 (141, 142) performs a so-called on-on type operation in the resonance type converter, and therefore, stabilizes this operation. Converter transformer 140 (1).
41, 142) by changing the degree of coupling between the primary winding and the secondary winding to increase the leakage inductance, equivalently providing an inductance component and omitting the choke coil 20 (143). It is possible.

Further, the high-voltage rectifier circuit of the high-voltage generation circuit section is composed of a multiple voltage multiplier circuit or a plurality of high-voltage windings of a high-voltage transformer as shown in FIGS. 8 and 9, a plurality of rectifier diodes, and a smoothing capacitor. The configured high-voltage rectification method may be appropriately changed and configured. Further, the configuration of a control system for power supply modulation for performing amplitude adjustment and pincushion distortion correction is not limited to the configuration of the above-described embodiment using the detection transformer 145. The configuration may be changed as appropriate.

[0081]

As can be seen from the above description, the present invention
First, a converter output circuit is configured by using a resonant converter capable of high-frequency switching operation and having a characteristic that switching waveforms are very smooth and have little switching noise and switching loss, and a converter transformer having a high-voltage generating portion. To generate high pressure
This high voltage is regulated using frequency control means, and the high voltage output circuit is directly output from the converter transformer in the power supply circuit unit by integrating the high voltage generation circuit and the power supply circuit that supplies other voltages with a simple circuit configuration. Made it possible to get
As a result, there is an effect that the main purpose of reducing the power loss can be realized by simplifying the switching circuit configuration and reducing the operation loss in the circuit.

Secondly, power supply modulation for amplitude adjustment and pincushion distortion correction is realized by providing an inductance control means using a saturable reactor having a characteristic of low switching noise and switching loss, thereby achieving high voltage generation and amplitude adjustment. And a power supply modulating unit that performs pincushion distortion correction, which realizes independent operations with a greatly simplified circuit configuration, and is an extremely effective solution for improving power loss during power supply modulation. To provide.

Third, a high-voltage generating circuit section having a large high-voltage load fluctuation and a power supply circuit section for supplying other voltages are provided by a frequency control means using a resonance type converter circuit having a small switching noise and a small switching loss; Simultaneous provision of power supply modulation control means for amplitude adjustment and pincushion distortion correction using a small number of saturable reactors enables the integration of a high-voltage generation circuit unit and a power supply circuit unit that supplies other voltages with a simple circuit configuration. This makes it possible to obtain high-voltage output directly from the converter transformer in the power supply circuit. As a result,
A constant voltage obtained from the converter transformer
By using the B voltage as the power supply voltage and obtaining a high-voltage output from the high-voltage transformer, the DC / DC conversion, which had been performed twice in the conventional method, is greatly improved by performing the DC / DC conversion once as described above. In addition, the conversion efficiency can be improved.

As described above, according to the present invention, there is provided a resonance type converter, a saturable reactor for amplitude adjustment and pincushion distortion correction, an insulated constant voltage power supply circuit, a high voltage generation circuit, and a power supply for amplitude adjustment and pincushion distortion correction. By configuring the power supply circuit by integrating the modulation function, low-noise, low-cost, high-frequency switching operation is promoted to reduce the size and weight, and the switching circuit configuration and transformer configuration are simplified. As a result, it is possible to greatly reduce the power loss and improve the conversion efficiency, and have the effect of reducing the power consumption of the product.

[Brief description of the drawings]

FIG. 1 is a block diagram of a switching power supply according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of the switching power supply according to the first embodiment.

FIG. 3 is a schematic view of a saturable reactor according to the embodiment.

FIG. 4 is a circuit diagram of a switching power supply according to a second embodiment.

FIG. 5 is a circuit diagram of a switching power supply according to a third embodiment.

FIG. 6 is a schematic view of a drive transformer using a saturable reactor for performing frequency control according to the embodiment.

FIG. 7 is a circuit diagram of a switching power supply according to a fourth embodiment.

FIG. 8 is a circuit diagram showing another example of the high-voltage rectifier circuit used in the embodiment of the present invention.

FIG. 9 is a circuit diagram showing another example of the high-voltage rectifier circuit used in the embodiment of the present invention.

FIG. 10 is a block diagram of a conventional switching power supply device.

FIG. 11 is a circuit diagram of a conventional switching power supply device.

FIG. 12 is an equivalent circuit diagram for explaining the operation of the half-bridge circuit.

FIG. 13 is an explanatory diagram of a current waveform of a half-bridge circuit.

FIG. 14 is an explanatory diagram of a relationship between a resonance characteristic and a switching frequency.

FIG. 15 is a circuit diagram of a conventional portion for modulating a power supply voltage.

[Explanation of symbols]

1 AC rectification smoothing circuit, 2 oscillation drive circuit, 3 converter circuit, 5 horizontal oscillation drive circuit, 6 horizontal output circuit,
7 horizontal deflection yoke, 11 cathode ray tube, 12 commercial AC power supply, 15, 35, 36, 41, 71, 72, 77, 8
0, 81, 84, 154, 156 resistance, 16, 42,
157 switching elements, 17, 18, 43, 44,
151 Dunbar diode, 19, 45, 78, 7
9, 152 resonance capacitor, 20, 46, 143 choke coil, 22 primary winding, 4, 21, 140, 14
1,142 converter transformer, 23-26,49
Secondary winding, 50 to 58, 89, 106 to 110, 123
~ 126 High voltage winding, 13,27,28,29,59 ~
68, 90-97, 111-122, 127-135
Rectifier diode, 158, 159 diode, 14,
30-34,69,70,98-105,136-13
9 Smoothing capacitor, 155 coupling capacitor, 73
Control circuit, 88 voltage source, 38 photocoupler, 86
Saturable reactor, 82 drive transformer, 83 inverting comparison amplifier, 85, 87 transistor, 144 horizontal output coil, 145 detection transformer, 146 horizontal deflection coil, 147 S-shaped capacitor, 150 horizontal output transistor, 153 pulse width control circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) EE18 EE45 EE65 EE73 EE74 FD01 FF01 FF18 FF19 FG07 ZZ16 ZZ18

Claims (6)

[Claims] 1. A rectifying / smoothing means for generating a rectified smoothed voltage across a smoothing capacitor using a rectified current obtained by rectifying a commercial AC power supply as a charging current, and a switching means for performing a switching operation using the rectified smoothed voltage as an operating power supply. An oscillation driving means for controlling a switching frequency connected to the switching means for performing the switching operation; a primary winding of a converter transformer constituted by an insulation type and a resonance capacitor, whereby the switching operation of the switching means is set to a resonance type. A high-voltage winding as a secondary winding of the converter transformer, and using a control signal obtained from an output of a high-voltage rectifier circuit connected to the high-voltage winding, to switch the switching frequency. Switching frequency control means for controlling the A saturable reactor is connected to another secondary winding of the saturable reactor, and inductance control means for controlling the inductance of the saturable reactor; A switching power supply device comprising: 2. The switching output means, wherein a primary winding of the converter transformer and the resonance capacitor are connected in series, so that a switching operation of the switching means is of a current resonance type. The switching power supply according to claim 1. 3. The switching output means has a first converter transformer and a second converter transformer, and the resonance capacitor is connected in series with a primary winding of the first converter transformer, and The switching operation of the switching means is of a current resonance type, the primary winding of the second converter transformer is connected in parallel with the primary winding of the first converter transformer, and the saturable reactor is connected to the second winding of the second converter transformer. The switching power supply device according to claim 1, wherein the switching power supply device is connected to a secondary winding of the converter transformer. 4. The switching output means, wherein a primary winding of the converter transformer is connected in series with the switching means, and the resonance capacitor is connected in parallel with the switching element, and the switching of the switching means is performed. The switching power supply device according to claim 1, wherein the switching power supply device is configured to operate in a voltage resonance type. 5. The oscillation driving means includes: a driving winding for driving the switching means; an excitation winding connected in series to a resonance current path of the switching output means; and the driving winding and the excitation winding. 2. A self-excited type frequency control circuit using a drive transformer including a saturable reactor having a control winding for controlling an inductance of the self-excited type. Switching power supply. 6. The high-voltage rectifier circuit connected to the high-voltage winding of the converter transformer has a multiple voltage rectification output circuit configuration, and the switching frequency control means outputs a signal from the multiple voltage rectifier circuit output. The switching power supply device according to claim 1, wherein the switching frequency is controlled using an obtained high-voltage control signal.