JPS6031149B2 - Oscillation frequency and voltage switching circuit in picture tube deflection circuit - Google Patents

Description

Detailed Description of the Invention The present invention relates to an oscillation frequency and exposure pressure switching circuit in a picture tube deflection circuit, and the output oscillation frequency can be reduced by providing one switching means between the oscillation means and the voltage circuit. It is an object of the present invention to provide a switching circuit configured to prevent abnormal voltage from occurring in a deflection coil by preventing a state in which the frequency is switched to a high voltage and a state in which the applied voltage is switched to a high voltage to not exist at the same time.

FIG. 1 shows a circuit diagram of an example of a conventional horizontal deflection circuit. In the figure, an output oscillation frequency synchronized with a horizontal synchronization signal from a horizontal oscillation circuit 1 is supplied to a horizontal output circuit 3 via a horizontal excitation circuit 2, and a deflection current with an intermittent sawtooth waveform is output from the horizontal output circuit 3. It is taken out. This deflection current is supplied to the horizontal deflection coil L, the linearity correction capacitor C, and the flyback transformer T. On the other hand, the power supply voltage +EB of the power supply voltage terminal 4 is voltage-adjusted by the power supply voltage adjustment circuit 5 and applied to the primary side of the flyback transformer T and the horizontal output circuit 3. The voltage boosted by the flyback transformer T is sent to a picture tube (not shown) via a high voltage rectifier circuit 6. Here, the oscillation frequency changeover switch S is changed to change the horizontal scanning period to Ts. From Ts2(
However, if Ts2>Ts. ), the transformer T,
The voltage applied to the horizontal output circuit 3 from the primary side of
When the inductance of the horizontal deflection coil L is Ly, the peak values ly and ly2 of the deflection current flowing through the capacitor C during the horizontal scanning period Tg and Ts2 are
, y. = Shimao・ , y2 Hanju 2.

At this time, assuming that the voltage E and the inductance Ly are constant, when switching to a shorter horizontal scanning period Ts and a longer horizontal scanning period Ts2, the amplitude of the horizontal deflection in the period Ts2 is compared to the amplitude in the period Ts. and become big. Therefore, conventionally, a switch S and a power supply voltage change-over switch S2 that operate in conjunction with the switch S are provided, and the movable saddle piece of the switch S is connected to the terminal b.
to obtain a high frequency and open the switch S2 to set the voltage E. In addition, the switch S, is connected to the terminal a to obtain a low frequency, and the switch S2 is closed to reduce the voltage E, thereby increasing the voltage E, according to the respective horizontal scanning periods Ts, , Ts2. A voltage is applied to the horizontal output circuit 3. However, since the switches S and S2 are separate switches, they may not operate at the same time, or chattering may occur, making it impossible to perform a reliable switching operation.

For example, as shown in FIG. 2A, at time t, switch S,
When the horizontal oscillation frequency is switched from a high frequency f, to a low frequency f,', for some reason, as shown in Fig. Assume that the voltage of the power supply voltage circuit 5 is switched from a high voltage E,' to a low voltage E,'. At this time, during the period from time t to t2, the horizontal oscillation frequency is low, that is, the horizontal scanning period is long, and the voltage is high.
Therefore, during this period, the deflection current ly
There were drawbacks such as an abnormal increase in the amount of noise and overloading of the horizontal output circuit 3. Furthermore, since the pulse voltage Vp generated on the primary side of the transformer T is proportional to the deflection current ly, the pulse voltage Vp also becomes abnormally high during this period, as shown in Figure D, and the voltage on the secondary side of the transformer T2 increases. There were drawbacks such as damage to the elements of the picture tube (not shown) and the elements of the tertiary side circuit of the transformer T. These phenomena occur at time t3 in FIG.
As shown below, this problem may also occur when the switches S, , S2 are switched in the opposite direction to the above. The present invention eliminates the above-mentioned drawbacks, and each embodiment thereof will be described with reference to FIG. 3 and subsequent figures.

FIG. 3 shows a circuit diagram of a first embodiment of the oscillation frequency and applied voltage conversion circuit in the deflection circuit according to the present invention. In the figure, the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted. In the figure, S3 is a single-pole dual-purpose make-after-break type switch, and its terminal c is connected to capacitor C2.
It is connected to the capacitor C3 and the horizontal oscillation circuit 1 through the capacitor C3, its movable saddle piece is grounded, and its terminal d is connected to the base of the transistor X through the resistor R. The emitter of transistor X is grounded, and its collector is connected via resistor R2 to the base of transistor X2 and to resistor R3. Power supply voltage terminal 4
is connected to the base of transistor X through resistor R4, and is also connected to resistor R3 and the collector of transistor X2. The collector of the transistor C5, and its emitter is connected to capacitor C4 and diode D. connected to the connection point. Note that the movable rear piece of switch S3 is terminal d.
If the movable rear half of switch S3 is connected to terminal c, transistor X, turns on and transistor X2 turns off. Yo,
The resistance values of each of the resistors R and R4 are set. The rest of the structure is the same as the conventional example shown in FIG. In the same figure,
The circuit surrounded by the broken line is the power supply voltage adjustment circuit 7, which together with the switch S3 constitutes a main part of the circuit of the present invention. Next, the operation of the above-mentioned constituent circuit will be explained.

In the figure, when scanning at a high horizontal oscillation frequency, when the movable piece of switch S3 is connected to terminal d, the horizontal oscillation frequency f, determined by the time constant of resistor R and capacitor C3, is output from horizontal oscillation circuit 1. Served. On the other hand, since the transistor X is off and the transistor X2 is on, the current from the power supply voltage terminal 4 passes through the transistor
Supplied to terminal q of the next winding. Note that the capacitor C4 is provided to bypass the alternating current flowing through the diode D without going through the transistor X2. In this case, the number of turns between the terminals p and q of the primary winding of the transformer L is n,
, qr, the number of turns between them is n2, and the voltage at the power supply voltage terminal 4 is EB, then the voltage E between the terminal p and the ground is E.
The voltage becomes the B+ band EB, which is higher than the voltage EB of the power supply voltage terminal 4.

This voltage E is applied to the horizontal output circuit 3, and a well-known horizontal deflection operation is performed at a high horizontal oscillation frequency f and a high voltage E. On the contrary, when scanning at a low horizontal oscillation frequency, when the movable piece of switch S3 is connected to terminal c, the horizontal oscillation circuit 1 connects resistor R and capacitor C2,
Horizontal oscillation frequency f determined by the time constant by C3,
' is extracted.

On the other hand, transistor X, is on, and transistor
2 is off, the current from the power supply voltage terminal 4 is supplied to the terminal p of the primary winding of the transformer T2 via the diode D2. In this case, the voltage E between terminal p and ground,
' is a voltage substantially equal to the voltage EB of the power supply voltage terminal 4.
This voltage E,' is applied to the horizontal output circuit 3, and a well-known horizontal deflection operation is performed at a low horizontal oscillation frequency f,' and a low voltage E,'. Here, if the movable twill of switch S3 is connected from terminal d to terminal c at time t, then the movable twill is connected between terminal d and terminal c for a period (from time t to t2).
), the output oscillation frequency of the horizontal oscillation circuit 1 is still a high frequency f. However, since the transistor X2 shifts from on to off, the current from the power supply voltage terminal 4 is supplied to the terminal p of the transformer T2 via the diode D2.

Therefore, during this period, the voltage at the terminal p becomes a low voltage E,' as shown in FIG. Eventually, the movable twill piece will move up to 2
When connected to terminal c, the output oscillation frequency from the horizontal oscillation circuit 1 becomes a low frequency f,' at time as shown in A of the same figure.
become. Therefore, during the period from time t to time ratio 2, the horizontal oscillation frequency is high and the voltage at terminal p is low, so the fourth
As shown in FIG. C, the pulse voltage Vp generated in the primary winding of the transformer T2 is smaller than the steady value. Next, if the movable piece of the switch S3 is connected from the terminal c to the terminal d at time t3, the period when the movable piece is between the terminal c and the terminal d (from time t4 to t4) is The output oscillation frequency switches to a higher frequency f at time t3 as shown in A in the figure, but since the transistors X, X2 remain in the same state, the voltage at terminal p of the primary winding of the transformer L is as shown in the figure. As shown in B, the voltage E,' remains unchanged.

Eventually, when the movable piece is connected to the terminal d, the transistor X2 changes from off to on, so the current from the power supply voltage terminal 4 flows through the transistor
, to the terminal q of the transformer T2. Therefore, the voltage at the iron terminal p becomes a high voltage E as shown in FIG. Therefore, as in the case from time 3 to time t2, the horizontal oscillation frequency is high and the voltage at terminal p is low during the period from time 3 to time t2, so as shown in Figure C, the primary winding of transformer L The pulse voltage Vp generated on the line is smaller than the steady value. As described above, in the above embodiment, the output oscillation frequency supplied from the deflection oscillation means to the deflection output means is switched according to the scanning period, and the voltage applied to the deflection output means is switched according to the scanning period. In a picture tube deflection circuit configured to obtain signals of oscillation frequency and voltage according to a scanning period, the voltage circuit is connected between the deflection oscillation means and the voltage circuit that supplies the voltage to be applied to the deflection output means, and either one of the By grounding the contact, the output oscillation frequency is lowered and the applied voltage is lowered when the scanning period is long. Therefore, when the applied voltage is switched from high to low, the output oscillation frequency decreases after a predetermined time delay. By switching from high to low and by grounding one of the other points, the output oscillation frequency is set high and the applied voltage is set high when the scanning period is short. When switched to high, it includes a single switching means consisting of a double pole single throw switch that switches the applied voltage from low to high after a predetermined time delay; switching the switching means ensures that the output oscillation frequency is low at any time. Since the configuration is such that the state in which the applied voltage has changed and the state in which the applied voltage has become high do not exist at the same time, the first
As in the follow-up example shown in the figure, the Calo voltage does not become large when the horizontal oscillation frequency is low. Therefore, the deflection current does not increase abnormally or excessive voltage occurs, and the picture tube, etc. Damage can be prevented.

FIG. 5 shows a circuit diagram of a second embodiment of the oscillation frequency and applied voltage switching circuit according to the present invention. In the figure, the same components as those in FIG. 3 are designated by the same reference numerals, and their explanations will be omitted. In the figure, S4 is a single-pole single-immersion switch, whose movable acid piece is grounded, and its terminal e is connected to capacitor C2 and to the base of transistor X3 via resistor R5. There is. The power supply voltage terminal 4 is connected to the base of the transistor X3 via a resistor R6, and
Connected to the collector of transistor X3. The collector of the transistor , and the connection point of capacitor C4. The rest of the structure is the same as that of the first embodiment shown in FIG. In the figure, the circuit surrounded by a broken line is the power supply voltage adjustment circuit 7'
This constitutes a main part of the circuit of the present invention together with the switch S4.
Next, the operation of the above circuit will be explained. In the same figure, when scanning at a high horizontal oscillation frequency, switch S
4, the horizontal oscillation frequency f, determined by the time constant of the resistor R and capacitor C3, is extracted from the horizontal oscillation circuit 1. On the other hand, the current from the power supply voltage terminal 4 is supplied to the base of the transistor X3 via the resistor R6, and the transistor X3 is turned on. The current from terminal 4 is supplied to terminal q of transformer T2 via transistor X3 and diode D. Here, as in the case of the first embodiment shown in FIG. 3, the high voltage E at the terminal p is applied to the horizontal output circuit 3, and the horizontal deflection is An action is taken. When scanning at a low horizontal oscillation frequency, when switch S4 is opened, the horizontal oscillation circuit 1 connects resistor R and capacitor C2.
, C3, the horizontal oscillation frequency f,' determined by the time constant is extracted.

On the other hand, since the current from the power supply voltage terminal 4 is grounded via the resistors R6, R5 and the switch S4, the transistor X3
is off. The current from terminal 4 is supplied to terminal p of transformer L via diode D2. Here, as in the case of the first embodiment shown in FIG.
,' are applied to the horizontal output circuit 3, and a horizontal deflection operation is performed at a low horizontal oscillation frequency f,' and a low voltage E,'. Here, since the switch S4 is a single-pole, single-throw type, the movable piece has only two states when it opens and closes: one is connected to the terminal e, and the other is not, so the output of the horizontal oscillation circuit 1 is The switching of the oscillation frequency and the switching of the voltage applied to the horizontal output circuit 3 are performed simultaneously and instantaneously.

In this way, the output oscillation frequency supplied from the deflection oscillation means to the deflection output means is switched according to the scanning period, and the voltage applied to the deflection output means is switched according to the scanning period, thereby generating oscillation according to the scanning period. In a picture tube deflection circuit configured to obtain frequency and voltage signals, the deflection oscillation means is connected to a connection line between the deflection oscillation means and the voltage circuit that supplies the voltage applied to the deflection means, and the connection line is grounded or ungrounded. Therefore, when the scanning period is long, the output oscillation frequency is lowered and the applied voltage is lowered. Therefore, when the applied voltage is switched from high to low, the output oscillation frequency is also switched from high to low. In order to shorten the output oscillation frequency and sometimes increase the applied voltage, a switching device consisting of a single-pole single-immersion switch that switches the output oscillation frequency from low to high and simultaneously switches the applied voltage from low to high. and a state in which the output oscillation frequency is switched to low, a state in which the applied voltage is switched to high, and a state in which the applied voltage is switched to high at any time by switching the switching means. Since it is configured so that it does not exist, the applied voltage is always small when the oscillation frequency is low, and furthermore, as there is no period corresponding to times L~t2 and ~t4 as in the first embodiment shown in FIG. 3, the pulse voltage There is almost no variation in Vp, and more stable switching can be performed. Note that when switch S4 is in the open state, the AC voltage generated at the connection point between capacitor C2 and switch S4 is usually a few volts, which is sufficiently small, and the resistance value of resistor R5 is sufficiently high, at 100 kilohms or more. The AC voltage has no effect on the on/off state of the transistor X3.

On the other hand, since the DC component supplied from the base of the transistor X3 to the capacitor C2 via the resistor R5 is blocked by the capacitor C2, there is no effect on the horizontal oscillation circuit 1. 6th
The figure shows a circuit diagram of a third embodiment of the oscillation frequency and applied voltage switching circuit according to the present invention. In the figure, the same components as those in FIG. 5 are denoted by the same reference numerals, and the explanation thereof will be omitted. In the same figure,
X4 is a transistor whose base is connected to the channel selector output terminal 8, whose emitter is grounded, and whose collector is connected to the diode D3 and the resistor R7.
It is connected to the horizontal oscillation circuit 1 via the diode D3 and the resistor R8, and is also connected to the resistor R5 of the power supply voltage adjustment circuit 7'. In addition, resistance R? When the connection point between R8 and R8 is grounded, the bias condition of the horizontal oscillation circuit 1 changes, and the output oscillation frequency is set to be lowered. The rest of the structure is the same as that of the second embodiment shown in FIG. next,
The operation of the above configuration circuit will be explained.

In the figure, when scanning at a high horizontal oscillation frequency, when the signal input to the channel selector output terminal 8 is turned off and the transistor X4 is turned off, the horizontal oscillation circuit 1 causes the resistance R? A horizontal oscillation frequency f2 determined by the bias conditions of R8 and R8 is extracted. On the other hand, the current from the power supply voltage terminal 4 is supplied to the terminal q of the transformer T2 as in the second embodiment, and the horizontal deflection operation is performed at a high horizontal oscillation frequency f2 and a high voltage E. When scanning at a low horizontal oscillation frequency, when a signal is supplied to the channel selector output terminal 8 to turn on the transistor Served. On the other hand, the current from the power supply voltage terminal 4 is supplied to the terminal p of the transformer T2 as in the second embodiment, and the horizontal deflection operation is performed at a low horizontal oscillation frequency ' and a low voltage E,'. Here, the switch for changing the horizontal oscillation frequency and the applied voltage is the transistor X4, and the effect is exactly the same as in the second embodiment.

Note that the diode D3 in the third embodiment is provided to prevent the current from the base of the transistor X3 from being supplied to the horizontal oscillation circuit 1 and changing its bias condition.

Further, a transistor or a thyristor may be used in place of the switch S4 in FIG. 5, which generally has a longer life than a switch using a contact and requires less power for control.

Furthermore, a mechanical switch, a thyristor, or the like may be used in place of the transistor X4 shown in FIG. As described above, the oscillation frequency and pressure switching circuit in the picture tube deflection circuit according to the present invention is connected between the deflection oscillation means and the voltage circuit that supplies the voltage to be applied to the deflection output means. When the scanning period is long, the output oscillation frequency is lowered and the applied voltage is lowered. Therefore, when the applied voltage is switched from high to low, the output oscillation frequency is switched from high to low at the same time or after a predetermined time delay, and In order to shorten the scanning period and sometimes increase the output oscillation frequency and the applied voltage, the applied voltage is switched from low to high at the same time as the output oscillation frequency is switched from low to high or after a predetermined time delay. A single switching means is provided, and the output oscillation frequency is switched to a low state and the applied voltage is switched to a high state at no time at the same time by switching the switching means. So,
No abnormal pulse is generated in the deflection means at any point during the switching operation of the switching means, and therefore no abnormal current flows through the deflection coil, which prevents damage to the picture tube and furthermore, The configuration is such that a single switching means consisting of a pole single-throw switch is connected to a voltage circuit that supplies voltage to be applied to the deflection oscillation means and the deflection output means and a connecting line, and the connecting line is grounded or ungrounded. , there is almost no fluctuation in the pulse voltage, resulting in more stable switching.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a circuit diagram of an example of a conventional horizontal deflection circuit and a diagram for explaining its operation, and FIGS.
The figures are a circuit diagram of the first embodiment of the oscillation frequency and haze pressure switching circuit in the picture tube deflection circuit according to the present invention, and a diagram for explaining its operation, and Figures 5 and 6 are respectively the present invention. It is a circuit diagram of the 2nd and 3rd Example of a kirinsuma circuit. 1...Horizontal oscillation circuit, 3...Horizontal output circuit, 4...Power supply voltage terminal, 7...Power supply voltage adjustment circuit, L...Flyback transformer, L... ...Horizontal deflection coil, S3, S4...Switch switch, X, ~
X4...transistor. Figure 1 Figure 2 Figure 4 Figure 3 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. The output oscillation frequency supplied from the deflection oscillation means to the deflection output means is switched according to the scanning period, and the voltage applied to the deflection output means is switched according to the scanning period. In a picture tube deflection circuit configured to obtain signals of oscillation frequency and voltage according to a period, the voltage circuit is connected between the deflection oscillation means and the voltage circuit for supplying a voltage to be applied to the deflection output means, and the scanning period is When the scanning period is longer, the output oscillation frequency is lowered and the applied voltage is lowered. Therefore, when the applied voltage is switched from high to low, the output oscillation frequency is switched from high to low at the same time or after a predetermined time delay. When the output oscillation frequency is short, the output oscillation frequency is set high and the applied voltage is set high. Therefore, a single switching means is provided that switches the applied voltage from low to high at the same time as the output oscillation frequency is switched from low to high or after a predetermined time delay. The image receiving apparatus is characterized in that, by switching the switching means, a state in which the output oscillation frequency is switched to low and a state in which the applied voltage is switched to high do not exist at the same time. Oscillation frequency and voltage switching circuit in tube deflection circuit. 2. By switching the output oscillation frequency supplied from the deflection oscillation means to the deflection output means according to the scanning period and at the same time switching the voltage applied to the deflection output means according to the scanning period, the oscillation frequency according to the scanning period is set. and a picture tube deflection circuit configured to obtain a voltage signal, which is connected between the deflection oscillation means and a voltage circuit that supplies a voltage to be applied to the deflection output means, and one of the contacts is grounded. Therefore, when the scanning period is long, the output oscillation frequency is lowered and the applied voltage is lowered. Therefore, the applied voltage is switched from high to low, and after a predetermined time delay, the output oscillation frequency is switched from high to low. By grounding one contact and the other, when the scanning period is short, the output oscillation frequency is made high and the applied voltage is made high. Therefore, the output oscillation frequency is switched from low to high and applied after a predetermined time delay. A single switching means consisting of a double-pole single-throw switch is provided to switch the voltage from low to high, and by switching the switching means, the output oscillation frequency is switched to low and the applied voltage is switched to high at any time. An oscillation frequency and voltage switching circuit in a picture tube deflection circuit, characterized in that the oscillation frequency and voltage switching circuit is configured such that a switched state does not exist at the same time. 3. The output oscillation frequency supplied from the deflection oscillation means to the deflection output means is switched according to the scanning period, and the voltage applied to the deflection output means is switched according to the scanning period, thereby changing the oscillation frequency according to the scanning period. and a picture tube deflection circuit configured to obtain a voltage signal, which is connected to a connection line between the deflection oscillation means and a voltage circuit that supplies a voltage to be applied to the deflection means, and the connection line is grounded or ungrounded. Therefore, when the scanning period is long, the output oscillation frequency is set low and the applied voltage is set low. When the period is short, the output oscillation frequency is set high and the applied voltage is set high.
A switching means is provided for switching the output oscillation frequency from low to high and at the same time switching the applied voltage from low to high, and by switching the switching means, the output oscillation frequency is switched to low at any time. An oscillation frequency and voltage switching circuit in a picture tube deflection circuit, characterized in that the circuit is configured such that a state in which the voltage is switched to high does not exist at the same time. 4. The oscillation frequency and voltage switching circuit in a picture tube deflection circuit according to claim 3, wherein the switching means includes a switching means made of a transistor.