JP2650999B2 - Horizontal deflection circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a horizontal deflection circuit in a display device using a cathode ray tube (CRT).

[Conventional technology]

Normally, a power supply voltage of a horizontal deflection drive circuit used for a television receiver or the like (hereinafter, referred to as a drive voltage).
Has a fixed voltage value. However, unlike a television receiver or the like, a CRT display used at the end of a computer or the like needs to adjust the horizontal display size in accordance with the specification required by the user. At this time, by changing the horizontal deflection current flowing through the horizontal deflection coil, it is possible to display screens having different horizontal display sizes with the same circuit.

However, in this case, the collector current flowing through the horizontal output transistor must also be changed. Therefore, in order to keep the driving conditions of the horizontal output transistor optimal (minimizing loss) for different collector currents, it is necessary to adjust the drive voltage according to the change in the collector current.

FIG. 6 shows the horizontal deflection current IDY and the optimum drive voltage EDO.
The relationship with (a drive voltage for minimizing the loss of the horizontal output transistor) is shown by a solid line. From FIG. 6, it can be seen that the optimum drive voltage EDO increases linearly with the increase of the horizontal deflection current IDY. That is, the horizontal deflection current I
Assuming that the optimum drive voltage EDO = ED1 when DY = I1 and the optimum drive voltage EDO = ED2 when the horizontal deflection current IDY = 12, Can be expressed as

FIG. 7 shows the relationship between the horizontal deflection current IDY and the loss PC of the horizontal output transistor. In FIG. 7, the solid line is when the drive voltage ED is the optimum drive voltage EDO (follows the change in the horizontal deflection current IDY), and the chain line is the fixed voltage ED2 (the optimum when the horizontal deflection current IDY = I2). , The dotted line indicates the case where the drive voltage ED is a fixed voltage ED1 (optimal when the horizontal deflection current IDY = I1).

In FIG. 7, when the drive voltage ED = ED0, the loss PC = P1 at the horizontal deflection current IDY = I1, and the loss PC = P2 at the horizontal deflection current IDY = I2, the drive voltage ED = ED1, the horizontal When the deflection current IDY = I1, the loss PC = P1,
At the horizontal deflection current IDY = I2, the loss PC increases to PC = P2 '. When the drive voltage ED = ED2, the loss PC = P2 at the horizontal deflection current IDY = I2, but the loss PC = P1 'at the horizontal deflection current IDY = I1.

That is, when the drive voltage ED = ED1, the saturation voltage increases due to insufficient driving due to the increase in the horizontal deflection current IDY, and when the drive voltage ED = ED2, the switching loss due to the overdrive due to the decrease in the horizontal deflection current IDY. (Accumulation time / fall time increases) becomes a problem.

As described above, when the drive voltage ED is fixed, a change in the horizontal deflection current IDY deviates from the optimum drive condition, so that a decrease in safety and reliability due to an increase in the loss PC becomes a problem.

On the other hand, as a conventional technique for automatically adjusting the drive voltage in accordance with a change in the horizontal deflection current (change in the collector current), there is a method disclosed in Japanese Utility Model Laid-Open No. 62-147959.

This conventional example is shown in FIG. In the figure, 200 is a horizontal drive circuit, 300 is a horizontal drive transistor, 400
a is a primary winding of a horizontal drive transformer, 400b is a secondary winding of a horizontal drive transformer, 500 is a horizontal output transistor, 600 and 600a are damper diodes, 700 and 700a are resonance capacitors, 800 and 800a are S-shaped capacitors, and 900 is a horizontal capacitor. A deflection coil, 900a is a dummy coil, 100A is a flyback transformer, 160 is a coil for blocking horizontal components, 170 is a transistor for horizontal amplitude modulation, 180 is a diode modulation circuit, 110 is a resistor, and 120 is a control transistor.

The operation of such a conventional circuit will be briefly described. By applying a modulation signal (b) such as a vertical period parabolic wave voltage or a constant DC voltage to the base of the modulation transistor 170, a voltage between both ends of the S-shaped correction capacitor 800a is increased. The voltage is changed to perform left / right pink distortion correction and / or horizontal amplitude adjustment. That is, when the modulation signal (b) increases the emitter potential of the modulation transistor 170, the amplitude of the horizontal deflection current flowing through the deflection coil 900 decreases, and when the emitter potential is opposite, the amplitude increases.

Therefore, if the emitter potential increases, the base voltage of the control transistor 120 also increases, and the current flowing through the transistor 120 increases, so that the voltage at the point C decreases. Therefore, the drive transistor 30
When 0 is on, the current flowing through the primary winding 400a of the drive transformer decreases, and therefore the horizontal output transistor 500
The base current to is also reduced. At this time, as described above, the amplitude of the horizontal deflection current is reduced, and the amplitude of the collector current of the horizontal output transistor 500 is also reduced accordingly, so that the horizontal output transistor 500 is not overdriven. . Conversely, when the emitter potential of the modulation transistor 170 decreases, the drive shortage of the horizontal output transistor 500 is eliminated.

In this conventional example, a diode-modulated horizontal deflection output circuit with little screen distortion is used, but the drive voltage is formed by inverting the emitter voltage of the transistor 170 for controlling the horizontal deflection current. As a result, an optimum drive voltage corresponding to the change in the horizontal deflection current can be formed.

[Problems to be solved by the invention]

When a high-speed horizontal deflection operation with a high horizontal frequency is performed by using the conventional circuit shown in FIG. 8, loss at the drive resistor 110 becomes a problem. In order to drive, the energy input to the drive circuit must be increased.
Therefore, the current supplied through the drive resistor is large,
The loss in drive resistance is also large).

As a solution to this, it is effective to separate the power supply for the drive circuit from the power supply for the horizontal deflection output circuit and remove the drive resistance. (The drive circuit power supply has a lower power supply voltage than the power supply for the horizontal deflection output circuit.) To use).

However, when the power supply voltages of the drive circuit and the horizontal deflection output circuit are separated, when the power of the display set is turned on,
If the drive circuit power supply rises faster than the horizontal deflection output circuit power supply, the horizontal deflection output circuit may not start up normally.

Hereinafter, the reason will be described. During the period in which the rises of the two power supplies are shifted (when the rise of the drive circuit power supply is earlier), the drive current is not supplied to the collector current of the horizontal output transistor which increases with the increase in the power supply voltage of the horizontal deflection output circuit. The forward base current that increases as the voltage rises is larger than the optimum value. In such an overdrive state, the accumulation time of the horizontal pressure transistor is longer than in the steady state. On the other hand, the allowable range of the accumulation time is determined by the horizontal frequency (horizontal cycle), the duty of the drive pulse, the horizontal retrace period, and the like. Therefore, in the above overdrive state, there is a high possibility that the accumulation time exceeds this allowable range and the horizontal deflection output circuit enters an abnormal mode and stops its operation. This problem is more likely to occur in a high-speed horizontal deflection circuit having a higher ratio of the accumulation time to the horizontal period.

An object of the present invention is to provide a horizontal deflection circuit having a function of automatically adjusting a drive voltage in accordance with a change in horizontal deflection current, even when a power supply for a drive circuit and a power supply for a horizontal deflection output circuit are separated from each other. An object of the present invention is to provide a horizontal deflection circuit capable of reliably starting a set when power is turned on.

[Means for solving the problem]

As a first technique for achieving the above object, in the horizontal deflection circuit (diode modulation type horizontal deflection circuit) of the present invention, a voltage (hereinafter, referred to as a horizontal size voltage) corresponding one-to-one with a change in horizontal deflection current. , A drive voltage output circuit connected to the horizontal size voltage detection circuit, and a drive voltage limiting circuit connected to the output terminal of the drive voltage output circuit.

Also, as a second method for achieving the above object,
In the horizontal deflection circuit (diode modulation type horizontal deflection circuit) of the present invention, the modulation voltage inversion circuit, the drive voltage output circuit connected to the modulation voltage inversion circuit, the switch means connected between the drive voltage output circuit and the drive transformer, A power supply voltage detecting circuit for detecting a power supply voltage of the deflection output circuit and comparing the detected voltage with a predetermined voltage and outputting the result to a control terminal of the switch means, and a drive voltage limiting circuit connected to a drive transformer are provided.

[Action]

First, the operation when the first method of the present invention is used will be described. The horizontal size voltage detection circuit detects a horizontal size voltage corresponding to a change in the horizontal deflection current on a one-to-one basis. This horizontal size voltage is appropriately adjusted in amplitude and DC level and output to the drive voltage output circuit. The drive voltage output circuit controls the drive voltage based on the output voltage of the horizontal size voltage detection circuit. Therefore, when the power supply of the display set is turned on, even if the power supply voltage of the horizontal deflection output circuit is lower than the steady state (transient state), the drive voltage is set to an appropriate value (corresponding to a change in the collector current of the horizontal output transistor). . As a result,
It is possible to solve the problem that the horizontal deflection output circuit stops operating due to the overdrive of the horizontal output transistor.

The drive voltage limiting circuit is used to supply a drive voltage in an initial state (when there is no drive voltage limit circuit, the horizontal size voltage is 0 V in the initial state, so the drive voltage is also 0 V, The output transistor cannot be driven).

Next, the operation when the second method of the present invention is used will be described. The modulation voltage inverting circuit inverts the modulation voltage for size adjustment and side pin correction, and at the same time, sets the amplitude and DC level appropriately and outputs it to the drive voltage output circuit. The drive voltage output circuit controls the drive voltage supplied to the drive transformer based on the output voltage of the modulation voltage inversion circuit. At this time, switch means is connected between the drive voltage output circuit and the drive transformer, and conduction / non-conduction of the switch means is controlled based on the output voltage of the power supply voltage detection circuit. The power supply voltage detection circuit detects a power supply voltage supplied to the horizontal deflection output circuit, and outputs a result of comparing the detected voltage with a predetermined voltage to a control terminal of the switch means.

Specifically, the switch means is non-conductive when the power supply voltage of the horizontal deflection output circuit is lower than a predetermined voltage, and is conductive when the power supply voltage is higher than the predetermined voltage. Accordingly, the power supply voltage of the horizontal deflection output circuit becomes higher than the predetermined voltage, and the drive voltage that follows the change of the modulation voltage is supplied only during the period when the switch means is conducting.

The drive voltage limiting circuit serves to supply a drive voltage during a period when the switch is non-conductive (immediately after the power supply voltage of the horizontal deflection output circuit is lower than a predetermined voltage).

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition,
In the drawings, those having the same function are denoted by the same reference numerals.

First, four specific embodiments for realizing the first method of the present invention will be described.

FIG. 1 is a circuit diagram showing a first embodiment of the first technique of the present invention. In FIG. 1, 1 is a drive DC voltage E1 input terminal, 2 is a drive pulse input terminal, 3 is a size / side pin control voltage input terminal, 4 is a power supply voltage input terminal of a horizontal deflection output circuit, and 5 is a high voltage output terminal. , 11 is a drive transistor, 12 is a drive transformer, 13 and 15 are diodes, 14 is a base resistor, 16 is a horizontal output transistor, 17 is a damper diode, 18 is a modulation diode, 19 is a first resonance capacitor, and 20 is a second resonance capacitor. Resonance capacitor, 21 is a horizontal deflection coil, 22 is a first scanning capacitor, 23 is a modulation coil, 24 is a second scanning capacitor, 25 is a flyback transformer, 26 is a high voltage rectifier diode, 27 is an amplifier circuit, 51, 52,
54, 56, 57, 60 are resistors, 53, 55 are capacitors, 58 is an operational amplifier circuit, 50 is a drive voltage output transistor, 61 is a diode, 62 is a voltage source, 100 is a horizontal deflection drive circuit, 101 is a horizontal deflection output Circuit, 102 is horizontal size voltage detection circuit, 103
Is a drive voltage output circuit, and 104 is a drive voltage limiting circuit.

1, a horizontal deflection drive circuit 100 includes a drive pulse input terminal 2, a drive transistor 11, a drive transformer 12, diodes 13, 15, and a base resistor 14. A horizontal deflection output circuit 101 includes a horizontal output transistor 16, a damper diode. 17, modulation diode 18, first resonance capacitor 19, second resonance capacitor 20, horizontal deflection wheel 21,
First scanning capacitor 22, modulation coil 23, second scanning capacitor 24, flyback transformer 25, high-voltage rectifier diode
26, a high-voltage output terminal 5; a horizontal size voltage detection circuit 102; resistors 51, 52, 54, 56, 57, capacitors 53, 55, and an operational amplifier 58;
Reference numeral 103 denotes a drive DC voltage E1 input terminal 1, a drive voltage output transistor 59, and a resistor 60. A drive voltage limiting circuit 104 includes a diode 61 and a voltage source 62.

Although the output of the amplifier circuit 27 is connected to the connection point between the modulation coil 23 and the second scanning capacitor 24, it may be connected to the connection point between the first scanning capacitor 22 and the modulation coil 23.

Hereinafter, the operation of the first embodiment of the first method of the present invention shown in FIG. 1 will be described. In FIG. 1, a horizontal size voltage detection circuit 102 detects a horizontal size voltage VDY corresponding one-to-one with a change in the horizontal deflection current IDY. The horizontal size voltage VDY is obtained by setting the power supply voltage of the horizontal deflection output circuit 101 to EB,
Assuming that the voltage at the connection point between the modulation coil 23 and the second scanning capacitor 24 (hereinafter, referred to as modulation voltage) is VCS2, it can be expressed as follows: VDY = EB−VCS2 (2) The horizontal deflection coil 21 shown in FIG.
Assuming that the voltage at the connection point of the scanning capacitor 22 is VCS1, VCS1EB (3) If the size / side pin control voltage input from the size / side pin control voltage input terminal 3 is VS, then VSS VCS2 ... ( 4) Therefore, the horizontal size voltage VDY can be obtained by substituting the equations (3) and (4) into the equation (2) (first).
(See the dotted line in the figure). In the horizontal size voltage detection circuit 102 shown in FIG. 1, a differential amplifier circuit is used, and resistors 51, 52, 5
With the values of 4, 56 and 57, the amplitude and the DC level of the voltage output from the operational amplifier circuit 58 can be set appropriately.

In the drive voltage output circuit 103, the drive transformer 12
Is controlled on the basis of the output voltage of the horizontal size voltage detection circuit 102. In addition, the drive voltage limiting circuit 104 functions to set an initial value of the drive voltage ED in an initial state immediately after the display set is turned on (when the drive voltage limiting circuit 104 is not provided, the horizontal value in the initial state is set). (Because the size voltage VDY is 0 V, the drive voltage ED also becomes 0 V and cannot be started.) However, the drive voltage supplied from the drive voltage limiting circuit 104 is not more than the drive voltage corresponding to the minimum value of the variable range of the horizontal deflection current IDY.

By the operation of the horizontal size voltage detection circuit 102, the drive voltage output circuit 103, and the drive voltage limit circuit 104, the optimum drive voltage ED following the change of the horizontal display size (change of the horizontal deflection current IDY) can be supplied. Even when the power supply for the drive circuit and the power supply for the horizontal deflection output circuit are separated, the display set can be reliably started when the power is turned on.

That is, at the time of startup, the voltage is applied to the input terminal 1 of the drive DC voltage E1 in advance, and the voltage EB applied to the power supply voltage input terminal 4 of the horizontal deflection output circuit rises. As a result, when the emitter voltage of the drive voltage output transistor 59 becomes higher than the voltage input from the voltage source 62 through the diode 61, it means that the control has been started. In the meantime, the voltage source 62 supplies a constant control voltage to the drive transformer 12 via the diode 61.

FIG. 2 is a circuit diagram showing a second embodiment of the first method of the present invention. In FIG. 2, reference numeral 80 denotes a current sensor, 81 denotes a resistor, 82 denotes a diode, and 83 denotes a capacitor. The first embodiment shown in FIG. Different from the embodiment.

In the second embodiment shown in FIG. 2, the collector current ICP of the horizontal output transistor 16 detected by the current sensor 80 is used instead of the horizontal size voltage VDY. The waveform of the collector current ICP is converted into a voltage by the resistor 81, peak-rectified by the diode 82 and the capacitor 83, and input to the operational amplifier circuit 58. The output of the operational amplifier circuit 58 is input to the drive voltage output circuit 103, and the drive voltage ED is controlled based on the output of the operational amplifier circuit 58.

In the case of using the second embodiment, in addition to the effect of the first embodiment, there is an effect that it is possible to cope with a signal having a different horizontal frequency without adjustment (in the first embodiment, a change in the horizontal frequency). As a result, the horizontal deflection current IDY for the same horizontal size voltage VDY changes, so adjustment is necessary when the horizontal frequency changes).

Note that the signals detected by the horizontal size voltage detection circuit 102 correspond to one-to-one changes in the horizontal size (for example, a horizontal deflection coil) other than those described in the first and second embodiments. 21, Modulation coil 23, Dipper diode
17, any voltage may be used as long as the voltage is generated in the modulation diode 18, the first resonance capacitor 19, the second resonance capacitor 20, and the like and the current flowing therethrough.

FIG. 3 is a circuit diagram showing a third embodiment of the first technique of the present invention. In FIG. 3, 30 and 31 are resistors, 32 is a high-voltage stabilizing circuit, 33 is a level shift circuit, 34 is a pulse width modulation circuit, 35 is an addition circuit, and 36 is a choke coil. This is different from the first embodiment.

In FIG. 3, the choke coil 36 is connected to the modulation coil 23.
Is connected to the connection point between the first scanning capacitor 22 and the modulation coil 23, but may be connected to the connection point between the first scanning capacitor 22 and the modulation coil 23.

In the third embodiment shown in FIG.
Controls the power supply voltage EB 'input to the flyback transformer 25 so that the high voltage detected by the resistors 30 and 31 becomes constant. Here, the variation ΔEB ′ of the power supply voltage EB ′ is input to the addition circuit 35 via the level shift circuit 33, and is superimposed on the size / side pin control voltage VS. The output voltage VS 'of the addition circuit 35 is supplied to the modulation coil 2 via the pulse width modulation circuit 34 and the choke coil 36.
3 and the connection point of the second scanning capacitor 24.

In this way, by superimposing the variation ΔEB ′ of the power supply voltage EB ′ on the size / side pin control voltage VS, the horizontal size variation ′ (fluctuation of the horizontal deflection current IDY) due to the variation of the power supply voltage EB ′ is corrected. be able to.

Note that the amplifier circuit 27 shown in FIG. 1 may be used instead of the pulse width modulation circuit 34 (however, the pulse width modulation circuit
Using 34 has the advantage of reducing loss.)

When the third embodiment according to the first method of the present invention shown in FIG. 3 is used, in addition to the effect of the first embodiment of the first method of the present invention shown in FIG. And a high quality image with little horizontal size fluctuation can be obtained. In the horizontal size voltage detection circuit 102, a horizontal deflection output circuit 101
Of the power supply voltage EB 'and the modulation voltage VCS2. For this reason, the drive voltage ED can follow the change of the output voltage EB 'of the high-voltage stabilizing circuit 32 (see FIG.
In the figure, since only the modulation voltage VCS2 is detected, when a high-voltage stabilization circuit of the power supply voltage control method is added, the drive voltage cannot follow a change in the output voltage of the high-voltage stabilization circuit.)

FIG. 4 is a circuit diagram showing a fourth embodiment of the first technique of the present invention. In FIG. 4, 40 capacitors, 41 is a diode, 42 is a resistor, 43 is a base-collector current (iBC) blocking switch (hereinafter referred to as a BC blocking switch) of a horizontal output transistor, and these are added. This is different from the third embodiment shown in FIG.

In FIG. 4, the inter-BC current blocking switch 43 is connected between the drive transformer 12 and GND (the emitter terminal of the horizontal output transistor 16), but is connected between the drive transformer 12 and the base terminal of the horizontal output transistor 16. You may connect.

Hereinafter, before describing the fourth embodiment of the first method of the present invention shown in FIG. 4, a problem caused by the inter-BC current iBC will be described.

The current iBC between BC is determined by the damper diode 17 and the modulation diode.
18 is the current flowing in parallel with the damper current iD flowing through
The current ratio between the inter-current iBC and the damper current iD is determined by the ratio of the impedance of the current paths through which both flow. The sum of the inter-BC current iBC and the damper current iD corresponds to the value of the modulation current im flowing through the modulation coil 23 in the first half of the horizontal scanning period. Therefore, the smaller the horizontal display size and the smaller the horizontal deflection current IDY, the larger the inter-BC current iBC.

Thus, the horizontal output transistor 16 supplies the BC current iBC
, The optimal drive voltage is not always linear with respect to the change in the horizontal deflection current IDY. In particular,
As shown by the one-dot chain line (ED = ED0 ') in FIG. 6, when the horizontal deflection current IDY is small, the optimum drive voltage becomes larger than ED0' expressed by the above equation (1). this is,
This is because the reverse bias must be increased in comparison with the case where the inter-BC current uBC does not flow in order to extract the accumulated charge of the horizontal output transistor 16 increased by the inter-BC current iBC at a high speed (when the drive voltage ED is increased). For example, the reverse bias applied to the base of the horizontal output transistor 16 can be increased).

On the other hand, by using the inter-BC current blocking switch 43, the inter-BC current iBC can be blocked. Therefore, the optimum drive voltage can be made linear with respect to the change in the horizontal deflection current as shown by the solid line in FIG. 6, and the tracking between the horizontal deflection current and the drive voltage can be improved.

Next, a specific example of the second method of the present invention will be described. FIG. 5 is a circuit diagram showing an embodiment of the second method of the present invention. In FIG. 5, 71 and 74 are power supplies, 72 is a comparator, 73 is a resistor, 75 is switch means, and 105 is a power supply voltage. A detection circuit 106 is a modulation voltage inversion circuit. In FIG. 5, a power supply voltage detection circuit 105 includes resistors 51 and 52, a capacitor 53, and a voltage source 7
1. The modulation voltage inverting circuit 106 includes a comparator 72, and includes resistors 54, 56, 57, 73, a capacitor 55, a voltage source 74, and an operational amplifier circuit 58.

Hereinafter, the operation of the circuit shown in FIG. 5 will be described. The modulation voltage inverting circuit 106 in FIG. 5 inverts the modulation voltage VCS2 (or the size / side pin control voltage VS), and at the same time, sets the amplitude and DC level appropriately, and outputs it to the drive voltage output circuit 103. ing. Drive voltage output circuit 1
In 03, the drive voltage ED supplied to the drive transformer 12 is controlled based on the output voltage of the modulation voltage inversion circuit 106.

At this time, switch means 75 is connected between the drive voltage output circuit 103 and the drive transformer 12, and the conduction / non-conduction of the switch means 75 is controlled based on the output voltage of the power supply voltage detection circuit 105. This power supply voltage detection circuit
In 105, the power supply voltage E supplied to the horizontal deflection output circuit 101
B, and compares the detected voltage with a predetermined voltage output from the voltage source 71.
(This switch means 75
May be a mechanical switch such as a relay or a semiconductor switching element such as a transistor.

As a result, when the power supply voltage EB of the horizontal deflection output circuit 101 is lower than a predetermined voltage, the switch means 75 is controlled to be non-conductive, and when it is higher, the switch means 75 is controlled to be conductive. Therefore, the drive voltage ED that follows the change in the modulation voltage VCS2 is supplied only during the period when the power supply voltage EB of the horizontal deflection output circuit 101 becomes higher than the predetermined voltage and the switch means 75 is conducting. Note that the drive voltage control circuit 104 functions to supply the drive voltage ED during a period when the switch means 75 is non-conductive (immediately after the power supply voltage EB is lower than a predetermined voltage and the power supply is turned on).

As described above, even when the embodiment of the second method of the present invention is used, the same effect as that of the first embodiment of the first method of the present invention can be obtained.

〔The invention's effect〕

According to the present invention, in a horizontal deflection circuit having a function of automatically adjusting a drive voltage according to a change in a horizontal deflection current, even when a power supply for a drive circuit and a power supply for a horizontal deflection output circuit are separated from each other, a display is provided. It is possible to reliably start the set when the power is turned on.

As a result, the drive resistance required when the power supply for the drive circuit and the power supply for the horizontal deflection output circuit are conventionally used can be eliminated. Therefore, there is an effect that the loss generated by the drive resistance can be eliminated.

[Brief description of the drawings]

1 to 5 are circuit diagrams showing one embodiment of the present invention, FIG. 6 is a graph showing a relationship between a horizontal deflection current and an optimum drive voltage, and FIG. 7 is a diagram showing a relationship between a horizontal deflection current and a horizontal output transistor. FIG. 8 is a graph showing a relationship with loss, and FIG. 8 is a circuit diagram showing a conventional example of a horizontal deflection circuit. EXPLANATION OF SYMBOLS 100: Horizontal deflection drive circuit, 101: Horizontal deflection output circuit, 102: Horizontal size voltage detection circuit, 103: Drive voltage output circuit, 104: Drive voltage limiting circuit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Michitaka Osawa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Home Appliance Research Laboratory, Hitachi, Ltd. (72) Inventor Katsuhiko Watananami 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi In Video Engineering Co., Ltd. (56) References JP-A-62-147959 (JP, A) JP-A-62-238597 (JP, A) JP-A-1-164174 (JP, A) JP, U) Japanese Patent Publication No. 54-27215 (JP, B2)

Claims (5)

(57) [Claims] 1. A horizontal deflection drive comprising a drive transformer (12) having an output winding connected to a base terminal of a horizontal output transistor (16) and one end of an input winding connected to a drive transistor (11). A circuit (100), a collector terminal of the horizontal output transistor (16), a cathode terminal of a damper diode (17), one end of a first resonant capacitor (19), and a horizontal deflection coil ( One end of a first resonance circuit comprising a first scanning capacitor (21) and one end of an input side winding of a flyback transformer (25) is connected to an anode of the damper diode (17). Terminal and the first
The other end of the resonance capacitor (19) and the other end of the first resonance circuit are connected together to form a common connection point, and the common connection point is connected to the cathode terminal of the modulation diode (18). One end of a second resonance capacitor (20) is connected to one end of a second resonance circuit including a modulation coil (23) and a second scanning capacitor (24) connected in series with each other; An anode terminal of a modulation diode (18);
A horizontal deflection output circuit (101) formed by interconnecting the other end of the second resonance capacitor (20) and the other end of the second resonance circuit; A horizontal size voltage detection circuit (102) for detecting a voltage between both ends of the first scanning capacitor (22) as a quantity representing a horizontal size on a screen;
02), a drive voltage output circuit (103), which amplifies the detected voltage and supplies it to the input winding of the drive transformer (12);
When the voltage supplied from 3) to the input winding of the drive transformer (12) falls below a certain limit, a drive that supplies the fixed limit voltage to the input winding of the drive transformer (12) instead. And a voltage limiting circuit (104). 2. The horizontal deflection circuit according to claim 1, wherein
A horizontal deflection circuit, wherein the horizontal size voltage detection circuit (102) comprises a voltage detection circuit for converting a collector current of the horizontal output transistor (16) into a voltage and detecting the voltage. 3. The horizontal deflection circuit according to claim 1, wherein the power supply voltage EB supplied to the input winding of the flyback transformer (25) is supplied to the flyback transformer (2).
5) A high-voltage stabilizing circuit (32) for controlling and supplying a high voltage output from the output side winding to be constant, and an input of the flyback transformer (25) from the high-voltage stabilizing circuit (32). A voltage fluctuation detecting circuit (33) for detecting a fluctuation of the voltage supplied to the side winding and applying the fluctuation to one of both ends of the modulation coil (23). Characteristic horizontal deflection circuit. 4. The horizontal deflection circuit according to claim 1, 2 or 3, wherein a current flowing from the base to the collector of the horizontal output transistor (16) during the turning off in synchronization with the input of the drive pulse is performed. A horizontal deflection circuit comprising a switch (43) for blocking iBC). 5. A horizontal deflection drive comprising a drive transformer (12) having an output winding connected to a base terminal of a horizontal output transistor (16) and one end of an input winding connected to a drive transistor (11). A circuit (100), a collector terminal of the horizontal output transistor (16), a cathode terminal of a damper diode (17), one end of a first resonant capacitor (19), and a horizontal deflection coil ( One end of a first resonance circuit comprising a first scanning capacitor (21) and one end of an input side winding of a flyback transformer (25) is connected to an anode of the damper diode (17). Terminal and the first
The other end of the resonance capacitor (19) and the other end of the first resonance circuit are connected together to form a common connection point, and the common connection point is connected to the cathode terminal of the modulation diode (18). One end of a second resonance capacitor (20) is connected to one end of a second resonance circuit including a modulation coil (23) and a second scanning capacitor (24) connected in series with each other; An anode terminal of a modulation diode (18);
A horizontal deflection output circuit (101) formed by interconnecting the other end of the second resonance capacitor (20) and the other end of the second resonance circuit; A modulation voltage inverting circuit (106) for detecting a voltage between both ends of the second scanning capacitor (24), inverting a change in the detected voltage and outputting the inverted voltage, and amplifying an output of the modulation voltage inverting circuit (106); A drive voltage output circuit (103) for outputting
Switch means (75) connected between the output side of the drive voltage output circuit (103) and the input side winding of the drive transformer (12), and the input side winding of the flyback transformer (25). A power supply voltage detection circuit (105) for detecting the supplied power supply voltage (EB) and comparing the detected voltage with a predetermined voltage (71) to control the opening and closing of the switch means (75); A drive voltage limiting circuit (104) that supplies a constant limiting voltage from a voltage source (62) to a input winding of the drive transformer (12) via a one-way switching element (61) when the drive transformer (75) is open. And a horizontal deflection circuit comprising: