JPH04188959A - Deflection circuit - Google Patents

Abstract

PURPOSE:To dispense with a switching circuit, etc., by changing a source voltage by a voltage control part at every MUSE system or NTSC system. CONSTITUTION:The appropriate value of a supply source voltage is set at every MUSE system and NTSC system, or every horizontal deflection circuit 10 and high voltage generation circuit 2. Furthermore, voltages different at every system and circuit from the voltage control part 4 which inputs a DC voltage Vcc, right and left pin-cushion distortion correction voltage, and a system switching signal are supplied to the high voltage generation circuit 2 and the horizontal deflection circuit 10, and the required high voltage and horizontal defecting current can be obtained. Thereby, it is possible to dispense with the switching circuit and a coil.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is applicable to HDTV (MUSE system) and E
In a television receiver that can receive both DTV (NTSC system), a voltage control circuit is provided that adjusts the power supply voltage supplied to the circuit to an appropriate voltage for each system and generates a power supply voltage with left and right binction distortion correction voltages superimposed. The present invention relates to a deflection circuit provided.

[Conventional technology]

Conventionally, in a deflection circuit of an HDTV receiver or the like, a horizontal deflection circuit and a high voltage generation circuit have separate circuit configurations, as shown in FIG. 3, due to the amount of power handled. Here, HD
If the TV is also used, the horizontal oscillation frequency is HDTV.
(33,7KHz) and EDTv (31,5KH7), the optimum power supply voltage for both is different.
In the case of HDTV, it may be lower than that in HDTV, but it was generally used in common. Therefore, if no measures are taken during EDTV, there will be a problem that overscanning (excessive horizontal scanning fluctuation) will occur and the high voltage (cathode ray tube anode voltage) will become too high than necessary. In order to deal with this problem, a first switching circuit S-1, a second switching circuit SW2, and coils L32 and L34 are provided in both the high voltage generation circuit and the horizontal deflection circuit as shown in FIG. According to the switching signal input to 33, stv, , and sw2 are switched to the ■ side for EDTV and HDT.
When it is V, switch to the ■ side. In other words, EDTV
Only in this case, the above problem was solved by inserting coils L32 and L34 as a circuit. Further, the left and right binction distortion is corrected by the left and right binction distortion correction circuit 38 in FIG.
A method is generally used in which the sawtooth current flowing through the deflection yoke is controlled by the correction voltage input to the correction voltage input terminal 37 as shown in FIG.

[Problem to be solved by the invention]

Therefore, both the high voltage generation circuit and the horizontal deflection circuit require the switching circuit and the coil, but these circuits handle large currents and voltages, and therefore require large component ratings. Furthermore, switching the switching circuit while the receiver is operating may cause spark discharge due to the large currents and voltages being handled, which not only shortens the life of the switching circuit, but is undeniably dangerous. It had the following drawbacks. Furthermore, the left-right binction distortion correction also had the disadvantage of requiring a socket-rated component to directly control the deflection yoke current.

In view of the above-mentioned drawbacks, the present invention does not use the switching circuit and the coil, but sets the original supply power voltage to an appropriate value for each method and each circuit, and further applies a correction voltage to the voltage supplied to the horizontal deflection circuit. It is an object of the present invention to provide a deflection circuit which also corrects left and right binction distortion by superimposing the left and right binction distortion, and eliminates the left and right binction distortion correction circuit.

[Means to solve the problem]

The present invention provides an HDTV (MUSE system) and an H
In a television receiver that can receive both DTV (NTSC system), the input DC voltage is changed to the DC voltage for each system and each circuit according to the switching signal for each system, and the left and right binction distortion correction voltage is changed to the horizontal deflection voltage. The present invention provides a deflection circuit that is provided with a voltage control circuit that generates a power supply voltage that is superimposed on a circuit DC voltage and is supplied to the horizontal deflection circuit and the high voltage generation circuit.

[Function] As shown in FIG. 1, the voltage control unit 4 inputs the DC voltage VCC, the left and right binction distortion correction voltages, and the system switching signal, and outputs different output voltages for each system and each circuit from the high voltage generation circuit and Supplied to the horizontal deflection circuit to obtain the required high voltage and horizontal deflection current.

〔Example〕

Hereinafter, a deflection circuit according to the present invention will be explained based on the drawings. FIG. 1 is a deflection circuit diagram showing one embodiment of the present invention, FIG. 2(A) is a voltage control circuit diagram showing a specific example of the voltage control section 4 in FIG. Output and H in figure (A)
It is a correlation diagram which shows the correlation with DTV time etc. In Figure 1, 1 is a horizontal drive signal input terminal, 2 is a high voltage generation circuit, 3 is a high voltage output, 4 is a voltage control section, and 5 is a DC voltage (■c
c) Input terminal 6 is an input terminal for a system switching signal that distinguishes between HDTV and EDTV (hereinafter referred to as "mode");
Reference numeral 7 indicates an input terminal for the left and right binction distortion correction (hereinafter referred to as "PC correction") voltage, 8 indicates a DC voltage output terminal of the voltage control section 4 that is supplied to the high voltage generation circuit 2, and 9 indicates the horizontal deflection circuit 1.
0, a DC voltage output terminal of the voltage control section 4, and 10 a horizontal deflection circuit. 0 In FIG. 2, the same parts as those shown in FIG. 1 are designated by the same symbols.

FIG. 2(A) is a voltage control circuit diagram consisting of two broncs whose circuit configurations are almost similar. A circuit made up of TR21 to TR24 etc. outputs a voltage for the high voltage generation circuit to the output terminal 8, and a circuit made up of TR25 to TR28 etc. outputs the voltage for the horizontal deflection circuit to the output terminal 9. Since the PC correction voltage is not necessary for the high voltage generation circuit, it is input only to the circuit that outputs the voltage for the horizontal deflection circuit. Other inputs (■66, v bb, mode switching signal) are used in common. Here, v bb is a DC voltage for operating each transistor. The mode switching signal is a voltage that is at a "high level" for HDTV and "low level" for EDTV. Therefore, TR21 and Tl125 are "ON J" during HDTV.
Acts as a switch that turns off when using an LED TV.
Reference numerals 21 and 22 indicate inverting circuits that invert the phase of the mode switching signal, and connect TR22 and TR26 to TR21, , T
It performs an on/off switch action that is opposite in timing to R25. In this way, TR21 and TR22 and T
The reason why R25 and TR26 are turned on and off alternately is to obtain appropriate biases for TR23 and TR27. TR23 and TR24 and TR27 and TR28 are always in the "on" state, but their collector currents differ depending on the mode. As explained above, the collector voltages (that is, the outputs) of TR24 and TR28 are high during HDTV<low during EDTV, and the output terminal 9 becomes a voltage on which the PC correction voltage (parabolic voltage) is superimposed. FIG. 2 CB) illustrates the correlation between each mode and the output voltage for each circuit. Different voltage display codes mean different voltage values. The need for differences between HDTV and EDTV is as described above. The reason why the values for the high voltage generation circuit and the horizontal deflection circuit are different is due to circuit design reasons, and the values are not absolute and may be the same. The voltage waveform for the horizontal deflection circuit is a parabolic voltage superimposed on an average voltage as shown in the figure. The reason why the parabolic voltage is set in the illustrated direction is that for PC correction purposes, it is necessary to make the voltage relatively higher in the central part of the vertical scan than in the upper and lower parts.

The high voltage generation circuit 2 and the horizontal deflection circuit 10 are operated by the horizontal drive input using the output voltage of the voltage control section 4 as described above. These circuits use general horizontal deflection circuits used in ordinary television receivers, etc., separately for high voltage generation and horizontal deflection, and their basic operations are the same. However, in the case of the embodiment shown in Fig. 1, since the horizontal drive input signal is commonly used, the high voltage generation circuit and the horizontal deflection circuit are equipped with coils LL, C1, and L2 in the same figure.The drive conditions seen from the horizontal drive circuit are be almost the same. The coil L1 corresponds to the deflection yoke of the horizontal deflection circuit, and the coil L2 corresponds to the flyback transformer of the high voltage generation circuit. In this way, a high voltage output is output to the output terminal 3 of the high voltage generation circuit 2, and horizontal scanning is performed by the horizontal deflection circuit 10.

〔Effect of the invention〕

As explained above, according to the present invention, HDTV (M
Changes in horizontal amplitude, etc. for each system due to differences in the high voltage generation circuit and horizontal deflection circuit of a TV receiver that switches between USE system and HDTV (NTSC system) are measured using coils, switching circuits, etc. However, since the voltage control section changes the power supply voltage for each method, the switching circuit, etc. is no longer necessary, which greatly contributes to the safety and longevity of the equipment.

[Brief explanation of the drawing]

Figure 1 is a deflection circuit diagram showing one embodiment of the present invention, and Figure 2 (
A) is a voltage control circuit diagram, Fig. 2 (B) is a correlation diagram showing the correlation between the output of Fig. 2 (A) and H'D TV time, etc., and Fig. 3 is a conventional deflection circuit diagram for explanation. It is. In the figure, 1 is a horizontal drive signal input terminal, 2.31 is a high voltage generation circuit, 3 is a high voltage output terminal, 4 is a voltage control section, 5 is a DC voltage (V CC) input terminal, and 6.33 is a system switching signal input. terminals, 7.37 is the input terminal for left and right binction distortion correction voltage, 8.9 is the DC voltage output terminal, 10.3
4 is a horizontal deflection circuit, 11.35 is a deflection yoke, 32 is a first switching circuit, 36 is a second switching circuit, 38 is a left and right binction distortion correction circuit, Ll, L2, L31
L34 to L34 are coils, R21 to R32 are resistors, TR2
1 to TR2B are transistors, 21 and 22 are inverting circuits, and C1 and C21 are capacitors. Patent applicant: Fujitsu General Ltd.

Claims (1)

[Claims] HDTV (MUSE method) and EDTV (NT
SC method) In a television receiver that can receive both signals, the input DC voltage is set to the DC voltage for each method and each circuit according to the switching signal for each method, and the left and right pincushion distortion correction voltages are set to the horizontal deflection circuit. 1. A deflection circuit comprising a voltage control circuit that generates a power supply voltage superimposed on a direct current voltage for use in the horizontal deflection circuit and the high voltage generation circuit.