JP3363687B2 - Amplifier circuit for deflection circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical deflection circuit used in a color television, a projection television, etc.
The present invention relates to improvement of an amplification circuit used for a deflection circuit such as a convergence correction circuit.

[0002]

2. Description of the Prior Art Before describing an amplifier circuit for a deflection circuit according to a conventional example, a convergence correction circuit as an example of a deflection circuit equipped with the amplifier circuit will be described.
This circuit is a convergence correction circuit used in a color projection television,
It is a circuit that corrects the shift between the images displayed on the cathode ray tubes provided for the three colors of (red), G (green), and B (blue).

As shown in FIG. 3, this circuit includes an R deflection signal generation circuit (21R) and an R deflection output circuit (22R).
R), G deflection signal generation circuit (21G), G deflection output circuit (22G), B deflection signal generation circuit (21G)
B), a deflection output circuit (22B) for B, and R, G,
This is a circuit that supplies current to the deflection coils (Lr, Lg, Lb) provided in the cathode ray tubes of each color of B to deflect the electrons radiated to the cathode ray tube and corrects the convergence.

The respective functions, configurations and operations are R, G and B.
Therefore, only the R deflection signal generation circuit (21R) and the R deflection output circuit (22R) related to R will be described below, and description of the other circuits will be omitted. According to the R related circuit, the R deflection signal generation circuit (21R) allows various R related synchronization signals (Rsy).
nc) generates a deflection signal for R (Rs) and outputs it to the deflection output circuit for R (22R). Next, the R deflection output circuit (22R) amplifies the deflection signal (Rs), outputs the amplified signal to the R deflection coil (Lr), and deflects the electrons radiated to the cathode ray tube to perform convergence correction.

Subsequently, an amplifier circuit according to a conventional example used in the deflection output circuit of such a convergence correction circuit will be described. As shown in FIG. 4, this circuit includes a differential input section (1), a first constant current generating circuit (2),
It has a second constant current generation circuit (3) and an output amplification section (4), amplifies the deflection signal (AS) input to the differential input section (1) and outputs it to the deflection coil (L). Circuit.

First, when the power is turned on, a constant current is supplied from the first constant current generating circuit (2) to the differential input section (1) and an output amplifying section (4) is supplied from the second constant current generating circuit (3). ) Is supplied with a constant current, respectively, and thereby the differential input section (1) and the output amplification section (4) start operating. Next, the deflection signal (AS) is input to the base of the transistor (Q1) which is the non-inverting input of the differential input section (1), and the differential input section (1) is input.
The voltage is amplified by and is output to the output amplification unit (4).

Next, the output amplification section (4) current-amplifies the voltage-amplified deflection signal (AS) and outputs it to the deflection coil (L). The current flowing through the deflection coil (L) is converted into a voltage and fed back to the base of the transistor (Q2) which serves as the inverting input of the differential input section (1), and the operation is stabilized.

[0008]

However, in the above circuit, the positive power supply (+ Vcc) and the negative power supply (+ Vcc) rise imbalance when the differential amplifier circuit (1) is unstable when the power is turned on. The midpoint of the circuit shifts or the first and second constant current generating circuits (2, 3) do not start at the same time when the power is turned on, and one constant current generating circuit precedes the other constant current generating circuit. Often get up.

Particularly, when the second constant current generating circuit (3) starts up first, the output amplifying section (4) operates first when the differential input section (1) is not operating yet. Sisters,
Since the inrush current (Ik) flows through the path as shown in FIG. 5, there arises a problem that the circuit malfunctions and eventually leads to circuit breakdown. Such an inrush current occurs not only when the power is turned on but also when the power is turned off. Further, in the case of excessive input, that is, when a deflection signal (AS) of a large level exceeding the normal input level is input for some reason, a problem that an inrush current similarly flows occurs.

[0010]

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and as shown in FIG. 1, is an amplifier circuit for a deflection circuit for amplifying a deflection signal and outputting it to a deflection coil. A differential input section for voltage-amplifying the deflection signal, a first constant current generating circuit for supplying a constant current to the differential input section to operate the differential input section, and a current amplification for the voltage-amplified deflection signal. And an output amplification section for supplying the deflection coil to the deflection coil, and a second section for supplying a constant current to the output amplification section to operate the same.
After the constant current generating circuit and the circuit operation at power-on / off are unstable, the operations of the first and second constant current generating circuits are forcibly stopped to stabilize the circuit operation. An amplifier circuit for a deflection circuit having a mute circuit for simultaneously operating the first and second constant current generating circuits, and the first constant current generating circuit, the collector outputs the constant current. For supplying the differential input section to the first NP
The second constant current generation circuit has an N-type transistor, the second constant current generation circuit has a second NPN-type transistor whose collector serves as an output and supplies the constant current to the output amplification unit, and the mute circuit is turned on. The base-emitter potentials of the first and second NPN transistors are set to the same potential to stop these operations, and the power is turned off after a lapse of a fixed time from power-on to turn off the first and second NPN transistors. The potential between the base and emitter of the NPN transistor is set to
A second constant current generating circuit, a switching element for making the voltage operable, a resistor and a capacitor, and a differentiating circuit for determining the constant time when the switching element is turned on by the time constant of the resistor / capacitor. In the amplifier circuit for the deflection circuit according to the present invention and the first constant current generating circuit, a collector is an output and a first NPN transistor for supplying the constant current to the differential input section. In the second constant current generation circuit, the collector of the second constant current generation circuit serves as an output to supply the constant current to the output amplification unit.
The mute circuit has a PN transistor,
When turned on, the base-emitter potentials of the first and second NPN transistors are set to the same potential to stop these operations, and after a certain period of time has passed since the power was turned on, OF
F, a first switching element that sets the base-emitter potential of the first and second NPN transistors to a voltage at which the first and second constant current generating circuits can operate.
When turned on, the base-emitter potentials of the first and second NPN transistors are set to the same potential to stop these operations, and after a certain period of time has passed since the power was turned off, OF
Deflection according to the present invention, comprising: a second switching element that performs F, a resistor and a capacitor, and a differentiating circuit that determines the constant time when the switching element is turned on by the time constant of the resistor and the capacitor. The amplification circuit for the circuit and the deflection circuit are a vertical deflection circuit and a convergence correction circuit. / It is an object of the present invention to provide an amplifier circuit for a deflection circuit in which an inrush current caused by an imbalance of falling edges is suppressed and stable operation is possible.

[0011]

DETAILED DESCRIPTION OF THE INVENTION

(1) First Embodiment Hereinafter, an amplifier circuit for a deflection circuit according to a first embodiment of the present invention will be described with reference to the drawings. This amplifier circuit is a circuit which is mounted on the deflection output circuit of the general convergence correction circuit shown in FIG. 3 and which is used to amplify the deflection signal and output it to the deflection coil.

As shown in FIG. 1, the amplifier circuit includes a differential input section (11), a first constant current generating circuit (12), an output amplifying section (13), and a second constant current generating circuit (14). And a mute circuit (15) for amplifying the deflection signal (AS) input to the differential input section (11) and outputting it to the deflection coil (L). First, the configuration of the above circuit will be described. The differential input section (11) receives the deflection signal (A
S) is a circuit which voltage-amplifies and outputs it to the output amplifier (13).

This has NPN type transistors (Q11, Q12) having a common emitter. The base of the transistor (Q11) is a non-inverting input, and the deflection signal (AS) is input from here. Further, the base of the transistor (Q12) serves as an inverting input, and the current flowing through the deflection coil (L) is converted into a voltage and input.
The collector of the NPN transistor (Q11) is connected to a positive power source (+ Vcc) via a resistor, and this collector serves as the output of the differential input section (11). NP
The collector of the N-type transistor (Q12) is directly connected to the positive power supply (+ Vcc).

The first constant current generating circuit (12) is a circuit for supplying a constant current to the differential input section (11) to operate it. This circuit has a collector (Q
11, Q12) are connected to a common emitter, the emitter is connected to a negative power supply (-Vcc) via a resistor, and the base is connected to a negative power supply (-Vc) via a diode (D10).
c) the first NPN transistor (Q1
3).

The output amplification section (13) is a circuit for current-amplifying the voltage-amplified deflection signal (AS) and outputting it to the deflection coil (L). This circuit is a push-pull output stage composed of a driver transistor (Q15), a Darlington-connected NPN transistor (Q16, Q17) and a Darlington-connected PNP transistor (Q18, Q19). It is composed of

The second constant current generating circuit (14) is a circuit for supplying a constant current to the output amplifying section (13) to operate it. In this circuit, its collector is connected to a transistor (Q15), its emitter is connected to a negative power source (-Vcc) through a resistor, and its base is a diode (D
It has the 2nd NPN type transistor (Q13) connected to the negative power supply (-Vcc) via 10).

The mute circuit (15) includes a first constant current generating circuit (1) and a second constant current generating circuit (1) for a predetermined fixed time after the power is turned on.
It is a circuit for operating these after stopping the operation of (2, 14). This circuit has a resistor (R) connected in series,
It has a differentiation circuit composed of a capacitor (C) and an NPN type switching transistor (Q20).

The switching transistor (Q20) is O
N, the potential difference between the emitter and base of the transistor (Q13) and the emitter of the transistor (Q14)
By reducing the potential difference between the bases together, the
In the F state, the first and second constant current generating circuits (12, 1)
The operation of 4) is stopped. Further, the differentiation circuit composed of the resistor (R) and the capacitor (C) connected in series determines the ON time of the switching transistor (Q20) by the time constant of the resistor (R) and the capacitor (C). . This ON time is set to be longer than the time when the circuit operation is unstable when the power is turned on.
It is set to less than a second.

Next, the operation of the above circuit will be described. First, the circuit is powered on. Then, from power-on, a fixed time determined by the time constants of the resistor (R) and the capacitor (C) of the mute circuit (15), that is, about 1
During less than a second, the capacitor (C) is charged through the grounded resistor (R), and the charging current (Ij) as shown in FIG.
Flows and the switching transistor (Q20) is turned on.

The switching transistor (Q20) is O
Then, the potential difference between the emitter and the base of the first NPN transistor (Q13) decreases, and at the same time, the second NP
The potential difference between the emitter and the base of the N-type transistor (Q14) also decreases, and these first and second NPN-type transistors (Q13, Q14) are almost turned off, so that the first and second constant currents are generated. The circuits (12, 14) do not operate during this time.

Therefore, since a constant current is not supplied to the differential input section (11) and the output amplification section (13), these do not operate even when the power is turned on. Next, leave the period when the circuit operation is unstable when the power is turned on, and remove the positive power supply (+ Vc
c), the negative power supply (-Vcc) stabilizes at a predetermined voltage, and the switching transistor (Q21) is turned off after a certain period of time determined by the time constant of the resistor (R) and the capacitor (C).

Then, the potential difference between the emitter and the base of the transistor (Q13) of the first constant current generating circuit (12) rises to a constant voltage determined by the diode (D10),
At the same time, the potential difference between the emitter and the base of the transistor (Q14) of the second constant current generating circuit (14) also rises in the same manner, so that these simultaneously start operating as constant current elements, and the first and second Constant current generation circuit (12, 1
4) rises at the same time and starts operation. At this time, one of the constant current generation circuits does not start up first as in the conventional case.

Then, the differential input section (11) and the output amplifying section (13) simultaneously start their operations, and the amplifying circuit enters a normal operating state. After that, the deflection signal (AS) is input to the base of the transistor (Q11) which is the non-inverting input of the differential input section (11), and the voltage is amplified by the differential input section (11) to output the amplification section (13). Is output to.

Next, the output amplification unit (13) current-amplifies the voltage-amplified deflection signal (AS) and outputs it to the deflection coil (L). The current flowing through the deflection coil (L) is converted into a voltage and fed back to the base of the transistor (Q12) which serves as the inverting input of the differential input section (11), thereby contributing to the stabilization of the operation. As described above, according to the amplifier circuit for the deflection circuit of this embodiment, the mute circuit (15) is used during the period in which the operation of the circuit is unstable when the power is turned on. Since the operation of the current generating circuits (12, 14) is stopped, the differential input section (1
1), the output amplifier 13 does not operate, and after the unstable period is over, the mute circuit 15 starts the first and second constant current generating circuits 12 and 14 simultaneously.

As a result, the positive power supply (+ Vcc) and the negative power supply (+ Vcc) rise unbalanced during a period in which the circuit operation is unstable when the power is turned on, and the midpoint of the circuit shifts, or the first and second circuits move. Since the constant current generating circuits (12, 14) do not start at the same time, it is possible to suppress the problem that has occurred conventionally that an inrush current flows. Therefore, it is possible to prevent the malfunction of the circuit and the destruction of the circuit.

Further, since the period in which the operation of the first and second constant current generating circuits (12, 14) is stopped by the mute circuit (15) is as short as less than 1 second, the resistance (R) and the capacitor (C) are It is possible to set the muting period with a time constant. Therefore, it is possible to realize this mute with an extremely simple circuit configuration consisting only of a resistor and a capacitor. For example, it is more costly than when this is configured with a mute circuit having a complicated circuit configuration such as that installed in an audio amplifier. There is also an advantage that can be realized cheaply.

In the present embodiment, the case where the above circuit is used for the convergence correction circuit has been described, but the present invention is not limited to this, and may be applied to a deflection output circuit of another deflection circuit such as a vertical deflection circuit. The same effect can be obtained by applying the above circuit to the amplifier circuit used. (2) Second Embodiment An amplifier circuit for a deflection circuit according to a second embodiment of the present invention will be described below. Descriptions of matters common to the first embodiment will be omitted to avoid duplication.

The amplifier circuit for the deflection circuit according to this embodiment is used in the deflection output circuit of the convergence correction circuit as in the circuit of the first embodiment, and is used for amplifying the deflection signal and outputting it to the deflection coil. This is the circuit used. This circuit includes a differential input section (21), a first
Constant current generation circuit (22), output amplification section (23), second
The constant current generating circuit (24) and the mute circuit (25) of the deflection signal (A
S) is amplified and output to the deflection coil (L).

First, the configuration of the above circuit will be described.
The differential input section (21) is a circuit that voltage-amplifies the input deflection signal (AS) and outputs it to the output amplification section (23). This has NPN type transistors (Q21, Q22) with a common emitter, as in the first embodiment.
The base of the transistor (Q21) has a non-inverting input, and the deflection signal (AS) is input from here. Further, the base of the transistor (Q22) serves as an inverting input, and the current flowing in the deflection coil (L) is converted into a voltage and input. Furthermore, the output is an NPN transistor (Q2
Taken out from the collector in 2).

The first constant current generating circuit (22) is a circuit for supplying a constant current to the differential input section (21). In this circuit, the collector is connected to the common emitter of the transistors (Q21, Q22), the emitter is connected to the negative power supply (-Vcc) through the resistor, and the base is connected to the negative power supply (through the diode (D10)). It has a first NPN transistor (Q23) connected to -Vcc).

The output amplifying section (23) is a circuit for current-amplifying the voltage-amplified deflection signal (AS) and outputting it to the deflection coil (L). This circuit is a push-pull output stage including a driver transistor (Q25), a Darlington-connected NPN transistor (Q26, Q27), and a Darlington-connected PNP transistor (Q28, Q29). It is composed of

The second constant current generating circuit (24) is a circuit for supplying a constant current to the output amplifying section (23). In this circuit, the collector is connected to the collector of the transistor (Q25), and the emitter is connected to the negative power source (-Vc) through the resistor.
c) and has a second NPN transistor (Q23) whose base is connected to the negative power supply (-Vcc) through the diode (D10).

The mute circuit (25) is a circuit for operating the mute circuit (25) after stopping the operation of the first and second constant current generating circuits (22, 24) for a predetermined fixed time after the power is turned on / off. Is. This circuit is the first in terms of circuit configuration.
Different from the circuit according to the embodiment. This mute circuit (2
5) is a differential circuit composed of a resistor (R) and a capacitor (C) connected in series, an NPN first switching transistor (Q30), a PNP second switching transistor (Q31), and a diode (D11). Have.

The first switching transistor (Q3
0) turns on the first NPN transistor (Q
23) the potential difference between the emitter and the base, and the second NPN
The potential difference between the emitter and the base of the type transistor (Q24) is reduced to bring them into an almost OFF state. This turns on only for a certain period when the power is turned on.

Second switching transistor (Q3
By turning on 1) also, the potential difference between the emitter and the base of the first NPN transistor (Q23), the second NP
The potential difference between the emitter and the base of the N-type transistor (Q24) is reduced so that they are almost turned off. This is different from the first switching transistor (Q30) and is turned on for a certain period of time after the power is turned off.

The differentiating circuit consisting of the resistor (R) and the capacitor (C) connected in series determines the ON time of the first and second switching transistors (Q30, Q31) by its time constant. Diode (D11)
Lowers the base potential of the first switching transistor (Q30) during the normal operation of the circuit, and simultaneously reduces the second potential.
Is a constant voltage element for increasing the base potential of the switching transistor (Q31) so that these first and second switching transistors (Q30, Q31) are not turned on during normal operation.

Next, the operation of the above circuit will be described. First, the circuit is powered on. Then, from power-on, a fixed time determined by the time constants of the resistor (R) and the capacitor (C) of the mute circuit (25), that is, about 1
During less than a second, the capacitor (C) is charged through the grounded resistor (R), the charging current (Ij1) flows through the path as shown in FIG. 2, and the first switching transistor (Q30) is turned on. .

The first switching transistor (Q3
0) is turned on, the first NPN transistor (Q2
3) The potential difference between the emitter and the base of 3) is reduced, and at the same time, the potential difference between the emitter and the base of the second NPN transistor (Q24) is reduced to reduce these transistors (Q2).
3, Q24) is almost off, so the first and second
The constant current generation circuit (22, 24) does not operate during this period.

Therefore, since a constant current is not supplied to the differential input section (21) and the output amplification section (23), they do not operate even when the power is turned on. Next, the unstable period when the power is turned on is removed, the positive power source (+ Vcc) and the negative power source (-Vcc) stabilize at a predetermined voltage, and a fixed period determined by the time constant of the resistor (R) and the capacitor (C) is set. After the capacitor (C) has been charged after the elapse, the base potential of the first switching transistor (Q30) is lowered by the diode (D11) and at the same time the base potential of the second switching transistor (Q31) is increased. Therefore, both of them are turned off.

Then, the potential difference between the emitter and the base of the transistor (Q23) of the first constant current generating circuit (22) rises to a constant voltage determined by the diode (D10),
At the same time, the potential difference between the emitter and the base of the transistor (Q24) of the second constant current generating circuit (24) also rises in the same manner, so that these simultaneously start operating as constant current elements, and the first and second Constant current generation circuit (22, 2
4) will start up and operate at the same time.

As a result, the differential input section (21) and the output amplification section (23) start their operations at the same time. After that, the transistor (Q21) which becomes the non-inverting input of the differential input section (21)
The deflection signal (AS) is input to the base of the, the voltage is amplified by the differential input section (21), and the voltage is output to the output amplification section (23).

Next, the output amplification section (23) current-amplifies the voltage-amplified deflection signal (AS) and outputs it to the deflection coil (L). The current flowing in the deflection coil (L) is converted into a voltage and fed back to the base of the transistor (Q22) which serves as the inverting input of the differential input section (21), and the operation is stabilized. After that, the power supply is cut off and the negative power supply (-Vc
When c) falls, the capacitor (C) is discharged for a certain period of time determined by the time constants of the resistor (R) and the capacitor (C) of the mute circuit (25) from when the power is turned on, that is, for less than about 1 second. Then, the discharge current (Ij2) flows through the path as shown in FIG. 2, whereby the second switching transistor (Q31) is turned on.

The second switching transistor (Q3
When 1) turns on, the first NPN transistor (Q2
3) The potential difference between the emitter and the base of 3) is reduced, and at the same time, the potential difference between the emitter and the base of the second NPN transistor (Q24) is reduced to reduce these transistors (Q2).
3, Q24) is almost off, so the first and second
The constant current generation circuit (22, 24) does not operate during this period.

Therefore, after the power is turned off, the positive power source (+ Vc
c) and the negative power supply (-Vcc) fall unbalanced, the midpoint of the circuit shifts, and the circuit operation becomes unstable. Since both (22, 24) have stopped operating, it is possible to suppress the occurrence of inrush current as much as possible by stopping the operation of one of the constant current generating circuits first during this unstable period. Become.

As described above, according to the amplifier circuit for the deflection circuit of the present embodiment, not only the same operation and effect as those of the circuit of the first embodiment can be obtained, but also the unstable operation when the power is turned off. At the same time, the mute circuit (25) operates to
Since the operation of the second constant current generation circuit (22, 24) is stopped, generation of an inrush current, which is apt to occur when the power is turned off in the past as well as when the power is turned on, and a malfunction of the circuit that causes this It is possible to suppress circuit destruction as much as possible.

Further, since the muting period is as short as less than 1 second, the muting period can be set by the time constant of the resistor (R) and the capacitor (C), and this muting is realized with a simple circuit configuration. Therefore, there is an advantage that the cost can be reduced as compared with a case where the mute is configured by a mute circuit having a complicated circuit configuration such as that used in an audio amplifier.

In the present embodiment, the case where the above circuit is used as the convergence correction circuit has been described, but the present invention is not limited to this, and is also applicable to the deflection output circuit of another deflection circuit such as the vertical deflection circuit. The same effect can be obtained by applying the above circuit to the amplifier circuit used.

[0048]

As described above, according to the deflection circuit of the present invention, the mute circuit causes the first and second constant current generating circuits to operate during a period in which the circuit operation during power-on / off is unstable. Since the first and second constant current generation circuits are operated at the same time after the operation is forcibly stopped and the circuit operation is stabilized, the positive power supply is used during the period when the circuit operation is unstable at power-on / off. And the negative power supply rise to an imbalance and the midpoint of the circuit shifts, or the first and second constant current generation circuits do not rise at the same time, resulting in the inrush current flowing. It becomes possible to deter.

Therefore, it is possible to prevent the malfunction of the circuit and the circuit destruction.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an amplifier circuit for a deflection circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of an amplifier circuit for a deflection circuit according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a general convergence correction circuit.

FIG. 4 is a circuit diagram of an amplifier circuit for a deflection circuit according to a conventional example.

FIG. 5 is a diagram illustrating a problem of an amplifier circuit for a deflection circuit according to a conventional example.

[Explanation of symbols] (11) Differential input section (12) First constant current generation circuit (13) Output amplifier (14) Second constant current generation circuit (15) Mute circuit (21) Differential input section (22) First constant current generation circuit (23) Output amplifier (24) Second constant current generation circuit (25) Mute circuit (AS) Deflection signal (L) Deflection coil (+ Vcc) Positive power supply (-Vcc) Negative power supply (R) Resistance (C) Capacitor (Q20) Switching transistor (Q13) First NPN transistor (Q14) Second NPN transistor (Q30) First switching transistor (Q31) Second switching transistor (Q23) First NPN transistor (Q24) Second NPN transistor (D11) Diode (Ij, Ij1) charging current (Ij2) discharge current

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Claims (4)

(57) [Claims] 1. An amplification circuit for a deflection circuit, which amplifies a deflection signal and outputs it to a deflection coil, comprising: a differential input section for amplifying the voltage of the deflection signal; and a first transistor. A first constant current generation circuit for supplying a constant current to the input section to operate them, an output amplification section for current-amplifying the voltage-amplified deflection signal and supplying it to a deflection coil ; The base is connected to the base
A second constant current generating circuit which has a second transistor and supplies a constant current to the output amplifying section to operate it, and the first and the first constant circuit during a period in which the circuit operation when the power is turned on is unstable .
The potential between the base and emitter of the second transistor is the same.
And a mute circuit for forcibly stopping the operations of the first and second constant current generating circuits and simultaneously operating the first and second constant current generating circuits after the circuit operation is stabilized. An amplification circuit for a deflection circuit, characterized in that 2. The first constant current generating circuit has a first NPN transistor whose collector serves as an output and supplies the constant current to the differential input section, and the second constant current generating circuit comprises: , A second NPN-type transistor whose collector serves as an output and supplies the constant current to the output amplifying section, and the mute circuit is turned on to output the first and second N-type transistors.
The base-emitter potential of the PN-type transistor is set to the same potential to stop these operations, and after a certain period of time has elapsed since the power was turned on, the power is turned off to turn off the first and second NPs.
A switching element for setting the potential between the base and the emitter of the N-type transistor to a potential at which the first and second constant current generating circuits can operate, a resistor and a capacitor, and the switching element is turned on.
An amplifier circuit for a deflection circuit according to claim 1, further comprising a differentiating circuit that determines the fixed period of time by a time constant of the resistor / capacitor. 3. The first constant current generating circuit includes a first NPN transistor, whose collector serves as an output and supplies the constant current to the differential input section, and the second constant current generating circuit. The circuit has a second NPN-type transistor whose collector serves as an output and supplies the constant current to the output amplification section, and the mute circuit is turned on to provide the first and second N-type transistors.
The base-emitter potential of the PN-type transistor is set to the same potential to stop these operations, and after a certain period of time has elapsed since the power was turned on, the power is turned off to turn off the first and second NPs.
A switching element for setting the potential between the base and the emitter of the N-type transistor so that the first and second constant current generating circuits can operate; and the base of the first and second NPN-type transistors which are turned on. The potentials of the emitters are set to the same potential to stop these operations, and the OF
A second switching element that turns on, a resistor and a capacitor are provided, and the switching element is turned on.
An amplifier circuit for a deflection circuit according to claim 1, further comprising a differentiating circuit that determines the fixed period of time by a time constant of the resistor / capacitor. 4. The amplifier circuit for a change circuit according to claim 1, wherein the deflection circuit is a vertical deflection circuit or a convergence correction circuit.