JPS6030471B2 - television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A television receiver has been proposed in which a horizontal deflection circuit and a high voltage generation circuit are provided separately.

In such a television receiver, the anode voltage of the cathode ray tube changes in response to changes in the beam current of the cathode ray tube, thereby changing the size of the image receiving screen. Various proposals have been made to avoid this problem. FIG. 1 shows an example of this, and to explain it, 1 is a DC power supply, 2 is an oscillator, and from these, a pulse approximately corresponding to a horizontal period can be obtained.

A signal obtained by this oscillator 2 is supplied to a high voltage generation circuit 3a and a horizontal deflection circuit 3b. These circuits 3a, 3
4a and 4b are drive transistors, 5a and 5b are damper diodes, and 6a and 6b are capacitors.
The collector of the transistor 4a is a flyback transformer 7
It is connected to the DC power supply 1 through the primary coil 7a, and one end of the secondary coil 7b is connected to the high voltage output terminal 9 through a diode 8 (high voltage rectifier). This is connected to an address of a cathode ray tube (not shown). The other end of the coil 7b is grounded through a resistor 10. On the other hand, in the horizontal deflection circuit 3b, 11 is a horizontal deflection coil, and 12 is a capacitor.

The signal (DC level) obtained across the resistor 10 described above is supplied to an intensifier 13 (DC intensifier), the output of which is supplied to the base of a transistor 14, and the emitter of this transistor 14 is transmitted through a coil 15. The above-mentioned horizontal deflection circuit 11 is connected to the collector of the transistor 4b, and the outside of the collector of the transistor 14 is connected to the power supply 1.

16 is a capacitor.

Note that the base of the transistor 14 is connected to a terminal 17 to which a parabolic signal that changes with a vertical period is supplied. In such a configuration, as the transistor 4a performs a switching operation by the pulse from the oscillator 2,
The output terminal of the high voltage generation circuit 3a has a high voltage. A piezoelectric voltage is generated,
Although not shown, this is supplied to the anode of the cathode ray tube.

On the other hand, since the pulse from the oscillator 2 is supplied to the transistor 4b, a deflection current is supplied to the gutter coil 11, which is known to perform horizontal scanning. In such an operating state, when the voltage obtained at terminal 9 fluctuates due to changes in the beam current of the cathode ray tube, the voltage across resistor 10 changes, which is multiplied by intensifier 13 and applied to the transistor. 14 bases supplied. Therefore, if the beam current increases and the voltage at the terminal 9 decreases, the internal impedance of the transistor 14 will increase, the current supplied to the deflection coil 11 will decrease, and the deflection output will also decrease. As a result, the change in the voltage at the terminal 9 and the change in the deflection output correspond to each other, thereby preventing the screen size from changing due to a change in the beam current. FIG. 2 shows this state, where a solid line 20 shows the high voltage obtained at the terminal 9, and a dotted line 21 shows the deflection output. However, according to such a configuration, since a so-called feedback circuit is used, a change in the deflection output to the deflection coil 11 in response to a change in the voltage at the terminal 9 is delayed in time.

That is, a phase shift occurs, which has the drawback of causing screen distortion. The present invention avoids such drawbacks, and an example thereof will be explained with reference to FIG. 3. Parts corresponding to those in FIG. 1 will be given the same reference numerals and their explanation will be omitted.

In the present invention, the flyback transformer 7 of the high voltage generating circuit 3a is provided with another secondary coil 7c in addition to the secondary coil for obtaining the high voltage shown in FIG. The circuit 3b is designed to supply operating current, and the coil 7b as seen from the primary side of the flyback transformer 7.
The leakage inductances of 7c and 7c are made equal to each other.

18 is a diode for rectification, 19 is a smoothing capacitor, and a DC power supply terminal for operation of the horizontal deflection circuit 3b.

FIG. 4 shows an equivalent circuit regarding the secondary coils 7b and 7c seen from the primary side of the flyback transformer 7, where Lo is inductance, Co is capacitance, and Ls
is the leakage inductance on the one secondary coil 7b side, LH is the leakage inductance on the other secondary coil 7c side, Cs is the high voltage rectification side capacitance, and CH is the capacitance of the capacitor 19. In order to construct the flyback transformer 7 so that the leakage inductances Ls and LH are equal to each other in this way, for example, as shown in FIG. If the secondary coils 7b and 7c described above are wound around the abutting portions 22a and 22b, respectively, the IJ-cage inductances of the respective IJs viewed from the primary coil 7a side can be selected to be equal to each other. It becomes possible.

In addition, as shown in FIG. 6, when each coil 7a, 7b, 7c is wound on a common magnetic core 21b, the coils 7b and 7c are wound on the coil 7a, and in this case, either one of the coils 7b and 7c is wound on the coil 7a. By interposing the insulator 23 between the coil (7c in the example of the drawing) and the coil 7a and appropriately selecting the thickness of the tube, the leakage inductance of the coils 7b and 7c as seen from the coil 7a can be made mutual. can be made equal to

In such a configuration, since the glue-cage inductances of the coils 7b and 7c are equal, when the voltage of the high-voltage state 9 changes with a change in the anode current, the coil 7c power source changes. The voltage fluctuation at the terminal 201 also follows this, and therefore the deflection coil 11
Since the current supplied to the anode also changes accordingly, that is, the horizontal deflection output changes in accordance with the magnitude of the anode voltage, it is possible to avoid the screen size from changing due to this.

Note that Cs and CH do not necessarily have to be equal. In this case, according to the present invention, as explained in FIG. 1, since no feedback circuit is used, voltage fluctuations at terminal 9 and terminal 201 are
There is no phase shift with respect to voltage fluctuations, and therefore, the drawbacks of the conventional method explained in FIG. 1 can be easily avoided.

Furthermore, according to the present invention, the purpose can be achieved only by winding yet another coil 7c around the flyback transformer 7 and selecting it so that its IJ cage inductance is equal to that of the coil 7b. There is no risk of structural complexity.

In the embodiment shown in FIG. 3, the coils 7b and 7c are wound so that their mutual IJ-cage inductances are equal as shown in FIGS. 5 and 6, but if necessary, It will be obvious that an inductance element may be inserted on the load side of the coil 7c, for example, between the emitter of the transistor 14 and the collector of the transistor 4b to perform a leakage effect.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an example of a conventional television receiver, FIG. 2 is a waveform diagram for explaining its operation, and FIG. 3 is a connection diagram showing an example of a television receiver according to the present invention. FIG. 4 is an equivalent circuit diagram thereof, and FIGS. 5 and 6 are side views each showing an embodiment of the flyback transformer. 3a is a high voltage generation circuit, 3b is a horizontal deflection circuit, 7 is a flyback transformer, and 9 is a DC voltage supply terminal to the anode terminal of the cathode ray tube. Figure 1 Figure 3 Figure 2 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. In a television receiver in which a high voltage generation circuit and a horizontal deflection circuit are separately provided, at least two secondary coils are provided in the transformer of the high voltage generation circuit, and the cathode rays are connected to one of the secondary coils. A current is supplied to the tube, and a current is supplied from the other secondary coil to the horizontal deflection circuit, and one of the two secondary coils is
The leakage inductances for the secondary coil and the other secondary coil are selected so that they are approximately equal, and the voltage fluctuations at the high voltage output end of the high voltage generation circuit and the operating current supply end to the horizontal deflection circuit correspond to each other. A television receiver characterized by being made to change depending on the direction of the image.