JPH01282971A - Horizontal deflection output circuit - Google Patents

Abstract

PURPOSE:To cause a horizontal deflecting width to be variable without inviting heating due to the large current of a horizontal deflecting coil by providing a means to switch the value of a resonance capacitor, which is parallelly connected with the horizontal deflecting coil of a deflection yoke. CONSTITUTION:Capacitors 21 and 22 to be serially connected constitute a resonance capacitor 5 of a horizontal deflecting coil 3. Since the transistor of a photo-coupler 26 is turned on in a condition that a switch 28 is closed, a semiconductor 23 goes to a turning-off condition and the capacitors 21 and 22 go to a serial condition for the resonance capacitor 5. Since the transistor of the photo-coupler 26 is turned off when the switch 28 is opened, the semiconductor element 23 goes to a turning-on condition. Then, since the resonance capacitor 22 goes to a short-circuit condition, the resonance capacitor 5 of the horizontal deflecting coil 3 is only the capacitor 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a horizontal deflection output circuit for a cathode ray tube display device.

[Conventional technology]

FIG. 2 is a diagram showing a horizontal deflection output circuit using a conventional diode modulator. In the figure, (1) is the water output transistor, (2) is the flyback transformer, (3) is the water deflection coil of the deflection yoke, (4) is the three-figure correction capacitor that also serves as a DC blocking capacitor, ( 5)
is the resonant capacitor of the horizontal deflection coil (3), (6) is the damper diode of the resonant circuit consisting of the wood wool deflection coil (3) and capacitor (5), (7) is the coil, and (8) is the DC blocking capacitor, (9) is the coil (7
) resonant capacitor, (101 is a dambada r-ode of a resonant circuit consisting of a coil (7) and a capacitor (9), (11) is a transistor, which modulates the voltage of the capacitor (8) by a human input signal. Wait for left and right pincushion distortion correction and width adjustment.

Next, the operation will be explained. Normally, horizontal deflection coils (3
) and its resonant capacitor (5) are selected to be the same as those of the coil (7) and its resonant capacitor (9), and the power supply voltage is set to Vcc and the capacitor (
When the voltages of 41i8) are respectively Vy and Vm, the following q equations hold true.

Vcc=Vy+Vm-=(1) The voltages of Vy and Vm serve as a power source for causing sawtooth wave current to flow through the water-V deflection coils (3) and (7). When the charging voltage Vm of the capacitor (8) is modulated by the transistor (11), the horizontal deflection current flowing to the horizontal deflection coil (3) is modulated based on the relationship of equation (1), and the water pincushion distortion is corrected. Further, by changing the DC operating point of the transistor (11), the horizontal deflection width can be changed.

Now, in display devices that are configured to accommodate various horizontal deflection frequencies and wide screen display widths,
In order to obtain an appropriate screen display width for the horizontal drive signal of each frequency, a transistor (11
) and appropriate voltage modulation for pincushion ↑ correction are required, and in this case the operating voltage range of the transistor (11) is in the range of 0 to Vm.

+j: As mentioned in i, if the resonant frequencies of the horizontal deflection coil (3) and the capacitor (5) and the resonant frequencies of the coil (7) and the capacitor (9) are the same, then the homo deflection coil (3) and the coil The inductance of (7) is ly
, Lm, then L y : L m = V y : V m --(
It has been well known that 21 holds true.

In a cathode ray tube display device, which maintains a constant high voltage output voltage even when the frequency of the horizontal drive signal manually applied to the horizontal output transistor (1) is switched, the high voltage is maintained by changing Vcc with respect to the frequency of the manually applied horizontal drive signal. The transistor (11) is configured to maintain the output type r) Z constant, and the operating voltage range of the transistor (11) satisfies equations (1) and (2). Then, the pincushion distortion correction and the variable range of the water/P deflection width within the operating voltage range are determined.

[Problem to be solved by the invention]

Since the conventional water deflection output circuit using a diode modulator is constructed as described above, the variable range of the water deflection width is limited by the operating voltage range of the transistor (11). In order to expand the variable range of water/V and deflection width, it is sufficient to increase the ratio of Vm to Vcc. It is necessary to increase the withstand voltage and increase the current of the horizontal deflection coil (3), which causes problems such as heat generation of the element and increase in price.

This is because, as shown in equation (2), an increase in the ratio of Vm means an increase in the ratio of l-m to y. Ly,
The sum of Lm is the horizontal output transistor (11 loads,
Since it must be constant under certain drive conditions, it is necessary to decrease y by increasing Lm. However, in order to obtain the same water fε deflection width, the water
When l and y of the deflection coil (3) decrease, a commensurate increase in current is required.

In this way, the conventional horizontal deflection output circuit that supplies a high output voltage from the flyback transformer (2) is a low frequency water drive signal, and when a wide horizontal deflection width is required. , L, and y, otherwise the operating range of the transistor (11) would be narrow and a sufficient horizontal width variable range could not be achieved.

This invention was made to solve the above-mentioned problems, and it does not require the pincushion distortion correction circuit and the water/L width variable circuit to have a high withstand voltage, and also does not require changing the ratio of Ly to 1, m. It is an object of the present invention to provide a water 1'-deflection output circuit which can flow an appropriate deflection current without any problems and has a wide variable range of horizontal deflection width.

[Means to solve the problem]

The water deflection output circuit according to the present invention is characterized in that it includes a horizontal deflection coil, IP, and means for switching the values of the resonant capacitors connected to the column.

[Operation] The resonant capacitor switching means in the present invention switches the value of the resonant capacitor connected in parallel with the horizontal deflection coil in accordance with the frequency of the large-force horizontal drive signal.

Therefore, most of the change in Vcc, which is changed to keep the high output voltage constant, becomes the voltage applied to the horizontal deflection coil, which increases the voltage resistance of the pincushion distortion correction circuit and the horizontal width variable circuit. Furthermore, the variable range of the water γ horizontal deflection width can be expanded without the need for a water-deflection coil and without generating heat due to a large current in the water-de polarizing coil.

[Embodiments of the invention]

An embodiment of the present invention will now be described with reference to the drawings. In FIG. 1, +211. (221 is a capacitor connected in series and constitutes the resonant capacitor (5) of the water f deflection coil (3). (23) is the resonant capacitor (22)
a semiconductor element connected in parallel to the semiconductor element (23), f241 is a Zener diode that maintains the drive voltage of the semiconductor element (23) constant, (25) is a resistor that supplies the drive voltage to the conductor element (23) from the capacitor (4), (26) drives (ON) the semiconductor element (23) without direct current coupling.
(27) is a resistor for driving the photocoupler (26), and (28) is a switch that turns the operation of the photocoupler (26) ON to 10FF.

Next, the operation will be explained.

When the switch (28) is closed, the transistor of the photocoupler (26) is turned on, so the semiconductor element (
23) is in the OFF state, and the resonant capacitor (5) is connected to the capacitors (211 and (221) in series. On the other hand, when the switch (28) is opened, the photocoupler (26)
Since the transistor is turned off, the semiconductor element (23)
is in the ON state and the resonant capacitor (22) is short-circuited, so that the only resonant capacitor (5) of the horizontal deflection coil (3) is the capacitor (21).

The pulse height value Vcp of the horizontal output transistor (1) is
Assuming that the high voltage output voltage is constant due to being kept constant, try: Retrace period of the horizontal deflection coil ts7: Scanning period of the horizontal deflection coil tryl: Horizontal deflection coil when the capacitor (22) is short-circuited retrace period tste1: scanning period trm of horizontal deflection coil when capacitor (22) is short-circuited: retrace period tgm of capacitor (9) and coil (7): retrace period of capacitor (9) and coil (7) It is expressed as a scanning period. When the capacitor (22) is short-circuited, its resonant frequency falls under t ry < t ryl, and the relationship in parentheses of the first term on the right side of equations (4) and (5) is as follows, and Vy<Vyl. .

The horizontal deflection current at this time is, and the increase in Vy is large compared to the decrease in Ls! <r
yt, therefore, by closing the semiconductor element (23) and shorting the capacitor (22), the horizontal polarization current increases and the horizontal polarization width can be increased.

In the above embodiment, a semiconductor element is used to switch the value of the resonant capacitor, but the same effect can be obtained by using a mechanical relay.

〔Effect of the invention〕

As described above, according to the present invention, a means for switching the resonant capacitor of the horizontal polarizing coil according to the frequency of the input horizontal drive signal is provided, so that the pincushion distortion correction circuit and the horizontal width variable circuit can be made to withstand high voltage, and the horizontal This has the effect of providing a horizontally polarized light output circuit that can change the width of horizontally polarized light without causing heat generation due to large electrification of the polarizing coil.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an embodiment of the present invention, and FIG. 2 is a block circuit diagram of a horizontal polarization output circuit using a conventional diode modulator. (1)...Horizontal output transistor, (2)...Flyback transformer, (3)...Horizontal polarizing coil, (5
). (21), (22)...resonant capacitor, (23)...
... Semiconductor element, (24) ... Zener diode,
(26)...Photocoupler, (28)...Switch. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A horizontal deflection output circuit using a diode modulator, characterized in that the horizontal deflection output circuit includes means for switching the value of a resonant capacitor connected in parallel with the horizontal deflection coil of the deflection yoke.