JPH0586112B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a deflection device for a television receiver, etc., and particularly to a deflection device for a television receiver, etc. This invention relates to a deflection device comprising means for preventing the above.

[Conventional technology]

Figure 3 shows a television receiver and a general CRT.
A typical basic circuit of a deflection device used in a display device is shown.

This basic circuit has a horizontal deflection output circuit 1 and a high voltage circuit 2. The horizontal deflection output circuit 1 includes a horizontal output transistor 3, a damper diode 4, a resonant capacitor 5, a horizontal deflection coil 6,
It consists of an S-shaped correction capacitor 7. The horizontal output transistor 3 performs a switching action in response to voltage pulses sent from a horizontal drive circuit (not shown), and applies a sawtooth wave current to the horizontal deflection coil 6 in cooperation with the damper diode 4. On the one hand, the resonant capacitor 5 and the horizontal deflection coil 6 generate flyback pulses by their resonant action, which are applied to the high voltage circuit 2.

The high voltage circuit 2 consists of a flyback transformer 8 and a high voltage rectifier diode 10. One side terminal of the low voltage coil (primary coil) 12 of the flyback transformer 8 is connected to the cathode of the damper diode 4,
It is connected to a common terminal of the horizontal deflection coil 6 and the resonant capacitor 5, and the other end terminal of the low voltage coil 12 is connected to an input power source 13. On the other hand, the high voltage side terminal of the high voltage coil (secondary coil) 14 of the flyback transformer 8 is connected to the anode 16 of the cathode ray tube 15 via the high voltage rectifier diode 10.
It is connected to the. In this configuration, the high voltage circuit 2 uses the flyback transformer 8 to step up the flyback pulse applied from the horizontal deflection output circuit 1, rectifies the signal using the high voltage rectifier diode 10, and outputs the rectified output _EH . It is added to the anode 16.

[Problem that the invention seeks to solve]

When operating a deflection device having the above-mentioned basic circuit, if a mistake occurs during design or manufacturing, an abnormality such as a short circuit may occur in the high voltage circuit 14 of the flyback transformer 8, which may cause a disaster such as a fire. Possible design errors include abnormal heat generation in the core 11 of the flyback transformer 8 and the high-voltage coil 14, or poor withstand voltage between the coils 12 and 14 or between the coil stacks. In addition, manufacturing errors include the occurrence of rare shorts due to mistakes during the winding work of coils 12 and 14, or
It is possible that an internal discharge or the like is caused by an insulation treatment error in steps 2 and 14.

Although the design and manufacturing of the deflection device is controlled to prevent the above-mentioned mistakes from occurring, it is difficult to completely eliminate such mistakes even if sufficient care is taken. Therefore, for example, a temperature fuse connected in series to the low voltage coil 12 or the input power supply 13 is disposed in the flyback transformer 8,
When the flyback transformer generates abnormal heat due to the above-mentioned mistake, the abnormal high-temperature heat generation is used to blow out the fuse and prevent the application of voltage to the flyback transformer 8, thereby preventing the occurrence of the above-mentioned disaster. is possible.

However, when arranging the above-mentioned temperature fuse, there is an extremely large potential difference between the temperature fuse and the high voltage coil 14, so if the temperature fuse is placed close to the coil 14, there is a problem that discharge will occur between the two. However, insulation treatment to avoid such discharge is extremely difficult. Also, in order to prevent the discharge, it is possible to separate the temperature fuse from the high voltage coil 14, but in that case,
This is disadvantageous in that the temperature of abnormal heat generated by the rear end of the high voltage coil 14 is difficult to be transmitted to the temperature fuse, delaying safety operation (fuse blowing operation), and making it impossible to prevent fires and the like. Furthermore, the drive frequency of the flyback transformer 8 is generally
Since it is high at 15.75KHz to 130KHz, low voltage coil 12
It is necessary to increase the degree of electromagnetic coupling between the high-voltage coil 14 and the high-voltage coil 14, but as mentioned above, it is necessary to install a large-sized one such as a temperature fuse inside the flyback transformer (for example, between the coils 12 and 14). Then,
There is also the problem that the degree of electromagnetic coupling is reduced and the basic performance of the flyback transformer 8 is impaired.

The present invention has been made in order to solve the above-mentioned conventional problems, and its purpose is to provide a means for quickly and reliably detecting abnormalities caused by the rare shorts of flyback transformers and preventing disasters from occurring. Moreover, by taking such measures, it is an object of the present invention to provide a deflection device that has almost no adverse effect on the basic performance of a flyback transformer.

[Means for solving problems]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention includes a horizontal deflection output circuit that receives an output signal from a horizontal drive circuit and generates a flyback pulse; boosts the flyback pulse from the horizontal deflection output circuit and supplies the output power to the anode side of the cathode ray tube. a flyback transformer; a protection fuse connected to the low voltage side of the low voltage coil of the flyback transformer; a primary current detection circuit that detects a current flowing through the low voltage coil of the flyback transformer; a secondary current detection circuit that detects the high voltage current flowing through the high voltage coil of the flyback transformer; the current capacity detected by the primary current detection circuit is the current detected by the secondary current detection circuit; a gate circuit that opens the gate when the capacitance becomes larger than the reference capacity of the gate; and a gate circuit configured as a closed circuit including a series connection of the low-voltage coil, the protective fuse, and the gate circuit; It is characterized by having a protection circuit through which the current flows.

[Effect]

In the present invention configured as above,
Under normal conditions when there is no abnormality in the flyback transformer, the current capacity detected by the primary side current detection circuit is less than the reference capacity of the current detected by the secondary side current detection circuit. Therefore, the gate of the gate circuit is closed, and no blowing current flows through the protection fuse of the protection circuit.

On the other hand, if an abnormality such as a reduction occurs in the high-voltage coil of the flyback transformer, the current flowing through the low-voltage coil increases rapidly. As a result, the current capacity detected by the primary current detection circuit changes to the current detected by the secondary current detection circuit (this current hardly increases even if a short circuit occurs in the high voltage coil). becomes larger than the reference capacitance of , and the gate of the gate circuit is opened. When the gate is released, a large-capacity blowing current (pulse current) flows through the protection circuit, and the protection fuse is blown. By blowing the fuse, application of voltage to the low voltage coil is blocked. The operation of the flyback transformer is stopped, and the occurrence of a fire or the like due to abnormal heat generation of the flyback transformer is prevented.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. In the description of this embodiment, the same reference numerals are given to circuit parts that are the same as those of the conventional example, and redundant explanation thereof will be omitted.

FIG. 1 shows a circuit configuration of a deflection device showing one embodiment of the present invention. In the figure, the deflection device includes a horizontal oscillation circuit (not shown), a horizontal drive circuit 17, a horizontal deflection output circuit 1, and a high voltage circuit 2.
and an abnormality detection/safety circuit 18. Among these circuits, the circuits other than the abnormality detection/safety circuit 18 are known, so the description of these known circuits will be simplified.

The horizontal drive circuit 17 has a drive transistor 20 and a drive transformer 21, and amplifies the horizontal pulse sent from the horizontal oscillation circuit and sends the voltage pulse, which has been waveform-shaped, to the horizontal deflection output circuit 1. It is added to.

The horizontal deflection output circuit 1 is constructed in the same manner as in FIG.

The high voltage circuit 2 consists of a flyback transformer 8 and a high voltage rectifier diode 10, and as in the case of FIG. 3, the flyback pulse applied from the horizontal deflection output circuit 1 is boosted by the flyback transformer 8, and further Signal rectification is performed by the high voltage rectifier diode 10, and the rectified output is transferred to the anode 1.
Add to 6.

The abnormality detection/safety circuit 18 reliably detects abnormalities such as rare shorts occurring in the high voltage coil 14 of the flyback transformer 8, and is a characteristic circuit of this embodiment. This abnormality detection/safety circuit 1
8 is a primary side current detection circuit 22, a secondary side current detection circuit 23, a gate circuit 24, and a protection circuit 25.
It consists of

The primary side current detection circuit 22 includes a low voltage coil 1
It consists of a parallel circuit of an AC path capacitor 29 that removes the AC component of the current I _B flowing through the current I _B , and a first detection resistor 26 that detects the DC component of the current I B from which the AC component has been removed. One end side of the parallel circuit 22 is connected to the positive side of the input power supply 13,
The other end of the parallel circuit 22 is connected to the protection circuit 25 side. Note that the negative side of the input power source 13 is connected to the ground side.

The secondary current detection circuit 23 is connected to the high voltage coil 1
4, a bias power supply 28, an AC path capacitor 30 that removes the AC component of the high voltage current _IH , and resistors 31 and ₃₂ . 2 detection resistor 2
One end side of the detection resistor 27 is connected to one end side of each of the resistors 31 and 32, and the other end side of the detection resistor 27 is connected to the negative side of the bias power supply 28.
The positive side of the power source 28 is connected to one end of the primary current detection circuit 22, that is, the positive side of the input power source 13. The other end of the resistor 31 is branched into two, one end of which is connected to one end of the AC pass capacitor 30, and the other end of the capacitor 30 is connected to a reference potential (ground side in the figure). . The other branch side of the resistor 31 is connected to the low voltage side (winding start side) of the high voltage coil 14. Note that the connection between this resistor 31 and the high voltage coil 14 is ABL (Automatic).
It leads to the Briteness Limitter) side.

On the other hand, in this embodiment, the gate circuit 24 is composed of a thyristor 33 and a capacitor 34 for noise removal, and the cathode side of the thyristor 33 is connected to the output end of the primary current detection circuit 22, that is, the AC path It is connected to the common terminal side of one end of the capacitor 29 and one end of the first detection resistor 26 . Further, the gate side of the thyristor 33 is the output terminal of the secondary current detection circuit 23, that is, the resistor 32
is connected to the other end. Also, capacitor 3
4 is connected between the cathode and gate of the thyristor 33.

The protection circuit 25 includes the low voltage coil 12 , a protection fuse 35 , a diode 36 , a smoothing capacitor 37 , and the thyristor 33 .
The cathode of the thyristor 33, one end of the smoothing capacitor 37, and one end of the protective fuse 35 are commonly connected to one end of the primary current detection circuit 22, and the other end of the protective fuse 35 is connected to one end of the low voltage coil 12. side (low pressure side). An intermediate tap is provided at an appropriate position of this low voltage coil, and the anode side of the diode 36 is connected to this intermediate tap, and the cathode side of the diode 36 is connected to the anode side of the thyristor 33 and the other end side of the capacitor 37. By being connected to the common connection part, a closed protection circuit 25 is formed.

Note that 38 in FIG. 1 indicates a transformer unit, and P ₁ to _{P 5} indicate terminals of the transformer unit 38.

In this embodiment configured as described above, when the brightness of the cathode ray tube 15 is increased during the circuit driving operation, the high voltage output current I _H applied to the anode 16 of the cathode ray tube 15 increases. On the other hand, if this high voltage output current I _H increases, the current I _B flowing from the input power supply 13 to the low voltage coil 12 also increases. This current I _B includes an AC component and a DC component, and the relationship between the DC component current I _BDC and the high voltage output current I _H is shown in FIG. According to this diagram the current I _BDC
is a constant DC component I _BDCO plus a variable DC component i _B that increases in proportion to the increase in high voltage output current I _H , and I _H is from 0 to the maximum value of the operating range.
When it changes to I _HM , I _BDC changes by ΔI _BDC .
The actual current of this I _BDC includes a large sawtooth wave component, but in Figure 2, even the average current value is small.
I Represents _BDC .

As mentioned above, when the brightness of the cathode ray tube 15 changes, the current I B is applied to the low voltage coil 12, and the current I _B is applied to the high voltage coil 1.
A high voltage current _IH flows through each of the terminals 4 and 4. Then, the DC component current I _BDC of the current I _B flowing through the low voltage coil 12
is detected by the primary side current detection circuit 22 as follows. That is, as a result of the AC component current of I _B being removed by the AC path capacitor 29, it is completely smoothed at both ends of the capacitor 29.
I A DC voltage proportional to _BDC appears. (The polarity is positive on the + side in the figure). In other words, the DC component current
The product of I _BDC and the resistance value R ₁ of the first detection resistor 28,
In other words, a voltage of e _B =R ₁ ×I _BDC appears, and the current capacity I _BDC of the DC component is indirectly converted to a voltage value e _B and detected. This detected value e _B is added to the cathode of the thyristor 33.

On the other hand, the high voltage current _IH flowing through the high voltage coil 14 is detected by the secondary current detection circuit 23 as follows. That is, when the high voltage current _IH flows through the secondary current detection circuit 23, its AC component is removed by the AC path capacitor 30, and if the resistance value of the second detection resistor 27 is _R2 , then The same resistor 27
A ripple-free DC voltage of e _R2 = I _H × R ₂ appears. This means that the high voltage current I _H indirectly
This means that it is converted into e _R2 and detected, and this detected value e _R2 is passed through the resistor 32 to the thyristor 33.
has been added to the gate.

In this embodiment, a bias power supply 28 is connected to the secondary current detection circuit 23 in order to balance the detection current capacities of both detection circuits 22 and 23.

In other words, when point Q of the circuit in FIG. 1 is taken as a reference point, a negative DC component flowing through the low voltage coil 12 (when viewed from point Q as a reference point, the current flowing through the low voltage coil 12 becomes a negative current) I As mentioned above, _BDC is the sum of the constant component I _BDCO and the variable component i _B , and in order to balance this constant component I _BDCO , the bias power supply 28
A negative voltage corresponding to the _IBDCO is applied to the second detection resistor 27 from the IBDCO. As a result, e _B and e _H
The balanced relationship between the two is replaced by the relationship between the DC changing component i _B flowing through the low voltage coil 12 and the high voltage current I _H flowing through the high voltage coil 14 .

The thyristor 33 has a negative voltage e _B on the cathode side that is more negative than the sum e _H of the negative voltage of the detected voltage value e _R2 and the voltage value E _S of the bias power supply 28, with reference to the Q point of the circuit in FIG. The gate is opened when the applied voltage level on the gate side becomes larger than the applied voltage level on the cathode side.
Conversely, when the negative voltage e _H becomes more negative than the negative voltage e _B , in other words, when the thyristor 33
The gate is closed when the applied voltage level on the cathode side becomes larger than the applied voltage level on the gate side, |e _H |≧|e _B , that is, under normal conditions when there is no short circuit in the high voltage coil 14. Therefore, in the circuit of this embodiment, the detection resistors 26 and 27
The resistance values R ₁ and R ₂ and the voltage E _S of the bias power supply 28
The operating point of the thyristor 33 is determined depending on how .

The process of determining R ₁ and R _{2 ES} can be expressed using the following formula.

First, the DC component I _BDC flowing through the low voltage coil 12
is expressed as I _BDC = AI _H + I _BDCO (1) (where A is a constant).

Furthermore, when point Q is the reference point, e _H and e _B are expressed as follows.

-e _H = I _H ×R ₂ +E _S ...(2) -e _B = I _BDC ×R ₁ ...(3) Substituting equation (1) into equation (3), -e _B = A x I _H ×R ₁ +I _BDCO ×R ₁ In normal operation without a reduction in the flyback transformer, as a condition for balancing the current capacity of the DC component current I _BDC flowing through the low-voltage coil 12 and the current capacity of the current I _H flowing through the high-voltage coil 14. e _B =
Since we can write e _H , I _H ×R ₂ + E _S = A × I _H × R ₁ + I _BDCO × R ₁ , so I _H × R ₂ = A × I _H × R ₁ ∴R ₂ = A × R ₁ E _S =I _BDCO × R ₁ In other words, R ₁ , R ₂ , and E _S are the circuit constants to be determined. Now, if E _S is determined first, R ₁ and R ₂ are R ₁
= E _S /I _BDCO , R ₂ = A x E _S /I _BDCO .

In this embodiment, if the value of E _S is set appropriately large with a margin in consideration of circuit variations, the thyristor 33 always remains in the OFF state during normal operation with no reduction in the flyback transformer. However, the gate is never opened.

On the other hand, if an abnormality such as rare short occurs in the high voltage coil 14 of the flyback transformer 8,
The changing component i _B of the current flowing through the low-voltage coil 12 increases rapidly, and especially in the case of an abnormality that causes the flyback transformer 8 to ignite, the increase in i _B will be nearly twice as much as ΔI _BDC in Fig. 2. It also becomes. That is, when a rare shot occurs in the high voltage coil 14, the current flowing in the low voltage coil 12 increases significantly, as described above. On the other hand, on the high-voltage coil 14 side, a large current circulates around the local closed circuit part created by the coil short, but the current flowing through the entire high-voltage coil 14 hardly changes due to the occurrence of the rare short (( Of course, when the rare short part is short-circuited to the ground side, a large current flows to the high-voltage coil, but normally even if a rare short part occurs, this rare short part is not short-circuited to the ground. In the invention), the detected current of the high voltage coil 14, which hardly changes due to the rare short of the high voltage coil, is used as a reference value, and this reference value is compared with the detected value of the primary side (low voltage coil side) current to detect the occurrence of rare short. As mentioned above, as a result of the rapid increase in i _B due to the ratio short, the negative detection voltage e _B corresponding to the current capacity detected by the primary current detection circuit 22 is detected by the secondary current detection circuit 23. When the negative detection voltage e _H corresponding to the reference current capacity becomes larger on the negative side, the thyristor 33 is turned on and the gate is opened at a point sufficiently before ignition.The opening of this gate causes a large pulse to be generated in the protection circuit 25. A current (fusing current) flows, and the protective fuse 35 is immediately blown.The blowing of the protective fuse 35 stops the operation of the flyback transformer 8, and prevents the occurrence of a fire or the like due to the short circuit of the flyback transformer 8. will be prevented.

In the above embodiment, the circuits for detecting the short circuit and ensuring its safety, that is, the circuits such as the primary and secondary current detection circuits 22 and 23, the gate circuit 24, and the protection circuit 25, are connected to the transformer unit 38. The unit is compactly formed within the unit 3.
The desired purpose can be achieved without introducing any operating signals from outside the 8. Therefore, there is no need to increase the number of terminals of the transformer unit 38, and the above purpose can be achieved simply by adding a circuit within the conventional transformer unit, which simplifies manufacturing and assembly of the device, and also makes handling easier. It is also extremely convenient.

In the above embodiment, a circuit configuration is shown in which the high voltage circuit and the horizontal deflection output circuit are not separated, but if they are separated, the horizontal deflection coil 6 and the S-shaped correction capacitor 7 become unnecessary. However, even in this case, only the horizontal deflection coil 6 can be replaced with a dummy inductance.

Further, the present invention is not limited to the circuit configuration shown in FIG. 1, and various circuit changes are possible.
For example, in the above embodiment, the bias power supply 28 is provided on the side of the secondary current detection circuit 23 to balance the constant DC component I _BDCO of the current flowing through the low voltage coil 12. The bias power supply that adds DC voltage is connected to the primary current detection circuit 2.
2 to cancel out the negative DC current component _IBDCO .

Further, in the circuit shown in FIG. 1, the high-voltage coil 14 is not wound in multiple parts, but it may be wound in multiple parts to form a multi-singular type. In this case, diodes are connected in series between each divided coil.

Furthermore, in this embodiment, the resistor 32 is connected to the gate side of the thyristor 33, but this resistor 32 may be omitted. can also be omitted if necessary. Further, in this embodiment, the thyristor 33 is used as the gate circuit, but this may be constructed from other circuit elements such as a transistor.

Furthermore, in this embodiment, an intermediate tap is provided on the low voltage coil 12 and the anode of the diode 36 is connected thereto, but this intermediate tap is omitted and the anode of the diode 36 is connected to the high voltage side of the coil 12. Good too. However, in this case, a high voltage is applied to the thyristor 33, which may cause problems in terms of the withstand voltage of the thyristor 33. Therefore, if an intermediate tap is provided and the diode 36 is connected, the voltage applied to the thyristor 33 will be reduced, and no problem will arise in terms of withstand voltage. If this intermediate tap is provided, the tap position will depend on the stone used for the thyristor 33 and will be provided at a safe winding position in terms of its pressure resistance.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to quickly and reliably detect abnormalities caused by the rare shoot etc. of the flyback transformer, and take safety measures to prevent the abnormalities caused by the abnormality of the flyback transformer. It is possible to prevent disasters such as fires from occurring.

In addition, it is not necessary to install a temperature fuse inside the flyback transformer to detect the abnormality, so the basic performance of the flyback transformer is not impaired.Furthermore, the circuit configuration is simple, so it is easy to use technology. This makes it possible to provide a deflection device that is extremely superior both in terms of both commercial and economical aspects. Furthermore, in the present invention, we have focused on the fact that even if a short circuit occurs in the high-voltage coil of a flyback transformer, the current flowing through the high-voltage coil hardly changes. Since it functions as a reference capacity (reference value) for comparison with the current capacity detected by the detection circuit, there is no need to separately prepare a dedicated reference power supply for comparison with the primary current detection capacity. This makes it possible to simplify the circuit configuration and reduce the cost and size of the device.

Furthermore, in the present invention, the protection circuit is configured as a closed circuit, and the closed path includes the low voltage coil, the protective fuse, and the gate circuit. Therefore, when a short circuit occurs in the high voltage coil, the flyback transformer connected to the transformer is damaged. The closed circuit on the primary side functions as a short circuit, and an extremely large short current flows through the closed circuit, making it possible to instantly blow out the protective fuse, resulting in extremely excellent safety operation response to the occurrence of a short short. Become something.

Furthermore, the present invention detects the current flowing through the low-voltage coil of the flyback transformer and compares it with the reference current capacity to detect the reduction of the flyback transformer. In case,
This rare short can be reliably detected by detecting a rapid change in the current of the low voltage coil, and the safety reliability for the rare short will be much higher.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing an embodiment of the present invention.
The figure is a characteristic diagram showing the relationship between the DC component current I _BDC flowing through the low-voltage coil and the high-voltage current I _H flowing through the high-voltage coil, and FIG. 3 is a general basic circuit diagram of a deflection device. 1...Horizontal deflection output circuit, 2...High voltage circuit, 3...Horizontal output transistor, 4...Damper diode,
5... Resonance capacitor, 6... Horizontal deflection coil, 7...
S-shaped correction capacitor, 8... flyback transformer, 10... high voltage rectifier diode, 11... core, 1
2...Low voltage coil, 13...Input power supply, 14...High voltage coil, 15...Cathode ray tube, 16...Anode, 17
...Horizontal drive circuit, 18...Abnormality detection/safety circuit, 20...Drive transistor, 21...Drive transformer, 22...Primary side current detection circuit, 23...
Secondary current detection circuit, 24...gate circuit, 25...
protection circuit, 26...first detection resistor, 27...second
Detection resistor 28...Bias power supply, 29...AC path capacitor, 30...AC path capacitor, 3
1, 32...Resistor, 33...Thyristor, 34...Capacitor, 35...Protection fuse, 36...Diode, 37...Smoothing capacitor, 38...Transformer unit.

Claims (1)

[Claims] 1. A horizontal deflection output circuit that receives an output signal from a horizontal drive circuit and generates a flyback pulse; boosts the flyback pulse from this horizontal deflection output circuit and supplies the output power to the anode side of the cathode ray tube. a flyback transformer added to the deflection device; a protective fuse connected to the low voltage side of the low voltage coil of the flyback transformer;
a primary current detection circuit that detects a current flowing through a low voltage coil of the flyback transformer; a secondary current detection circuit that detects a high voltage current flowing through a high voltage coil of the flyback transformer; a gate circuit that opens the gate when the current capacity detected by the secondary current detection circuit becomes larger than the reference capacity of the current detected by the secondary current detection circuit; a series connection of the low voltage coil, the protective fuse, and the gate circuit; and a protection circuit configured as a closed circuit including a gate circuit, through which a fuse blowing current flows when the gate of the gate circuit is open. 2. The gate circuit is composed of a thyristor, and the protection circuit has the cathode side of the thyristor connected to one end of a protective fuse, the other end of the fuse connected to the low voltage side of the low voltage coil, and the intermediate tap position of the low voltage coil connected to the protective circuit. The anode of the diode is formed by connecting the cathode side of the diode to the anode side of the thyristor, and
Claim 1, characterized in that the cathode side of the thyristor is connected to the output end of the primary side current detection circuit, and the gate side of the thyristor is connected to the output end of the secondary side current detection circuit. Deflection device. 3. The primary current detection circuit and the secondary current detection circuit each include a capacitor that removes the alternating current component of the detected current, and a resistor that converts the detected direct current value obtained by the capacitor into a voltage value. The deflection device according to claim 2, wherein a voltage converted by a corresponding resistor of each current detection circuit is applied to the cathode side and the gate side of the thyristor. Device. 4. Any one of claims 1 to 3, characterized in that one side of the primary-side current detection circuit and the secondary-side current detection circuit is equipped with a bias power supply for applying a bias current. The deflection device according to one.