JPH0110055Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a television receiver, and particularly aims to improve the horizontal output stage.

In current television receivers, the horizontal deflection section and the voltage generation section of the horizontal output stage are generally configured to be driven by the same horizontal output transistor. In addition, there are devices in which the horizontal deflection section and the voltage generation section are each driven by separate horizontal output transistors, but even in such devices, both the horizontal deflection section and the voltage generation section operate at the horizontal frequency. It's becoming like that.

Incidentally, although the horizontal deflection section naturally needs to be operated at a horizontal frequency, the voltage generation section does not necessarily need to be operated at a horizontal frequency due to its function. Nevertheless, the reason why the voltage generator is operated at the horizontal frequency is that the configuration of the horizontal output stage is simplified.

However, when the operating frequency of the voltage generator is as high as the horizontal frequency, power loss due to collector loss of the horizontal output transistor and hysteresis loss of the flyback transformer becomes a problem.

Therefore, the present invention provides a horizontal deflection section and a voltage generation section separately, drives the voltage generation section at a lower frequency than the horizontal deflection section, and sets the resonant frequency of the voltage generation section to be lower than the resonant frequency of the horizontal deflection section. By selecting a low value, the above-mentioned drawbacks can be solved. Hereinafter, details of the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 1 denotes a horizontal oscillation circuit, the output of which drives a horizontal deflection section 3 via a drive circuit 2. This deflection section 3 includes a horizontal output transistor Tr ₁ , a damper diode Dd ₁ , a deflection coil Ly, an S-shaped correction capacitor Cs, and a resonance capacitor.
Although it is equipped with Cr ₁ and Chiyoke transformer CT,
In this respect, there is no difference from a conventional horizontal deflection circuit. However, it should be noted that since a choke transformer CT is used instead of the conventional flyback transformer, the primary inductance can be selected to be larger than that of the conventional one, but the reason for this will be explained later. explain.

On the other hand, numeral 4 is a frequency step-down circuit that steps down the output of the oscillation circuit 1 to a suitable frequency, for example, 1/2, and its output drives the voltage generation section 6 via the drive circuit 5. . This voltage generating section 6 includes a horizontal output transistor Tr ₂ , a damper diode Dd ₂ , a resonant capacitor Cr ₂ , and a flyback transformer FT. The flyback transformer FT has a secondary winding N ₂ for picture tube anode voltage with a rectifier diode D ₀ etc. connected between the divided windings, a DC low voltage transistor connected with a diode D ₁ and a capacitor C ₁ . A tertiary winding N ₃ for power supply and a winding N ₄ for taking out horizontal pulses are provided.
The picture tube screen voltage is taken out from the primary winding _N1 by a diode _D2 and a capacitor _C2 , and the primary winding _N1 is connected to a DC high power supply with a diode _D3 and a capacitor _C3 . There is an intermediate tap for use. However, this embodiment is not characterized by the configuration of the voltage generating section 6 itself, but by the following points. That is, one of them is, as mentioned above, in order to operate the voltage generating section 6, that is, the horizontal output transistor Tr ₂ at a frequency sufficiently lower than the horizontal oscillation frequency, the horizontal oscillation frequency obtained from the horizontal oscillation circuit 1 is used to operate the horizontal output transistor Tr ₂ . One point is that it is driven by the output of the down-down circuit 4, which steps down the frequency.The other point is that the resonant frequency determined by the resonant capacitor _Cr2 of the voltage generator 6 and the primary inductance of the flyback transformer FT is controlled by horizontal deflection. Section 3 resonant capacitor
Cr ₁ and Chiyoke transformer CT and horizontal deflection coil Ly
This point is selected to be lower than the resonant frequency determined by

Another feature is that a secondary winding Nc is provided in the horizontal deflection transformer CT of the horizontal deflection unit 3, and the horizontal pulses extracted from this winding are used as a heater power source for the picture tube. Depends on the reason. That is, when the horizontal pulse for the heater power source is taken out from the flyback transformer FT of the voltage generating section 6, this horizontal pulse changes depending on the increase or decrease of the picture tube anode high voltage, that is, the beam current, as is well known. This is because it is not preferable as a heater power source.

As explained above, the present invention provides the horizontal deflection section of the horizontal output stage separately from the horizontal deflection section, drives the voltage generation section at a lower frequency than the horizontal deflection section, and drives the resonant frequency of the voltage generation section at the horizontal deflection section. Since the resonant frequency is lower than the resonant frequency of the horizontal deflection section, the collector loss of the horizontal output transistor in the voltage generation section and the hysteresis loss of the flyback transformer can be reduced. Since it is not necessary to carry out wave tuning, the inductance of this transformer can be increased, and the loss of this horizontal deflection section can also be reduced, so there is an advantage that the power consumption of the entire horizontal output stage can be reduced.

In addition, in the present invention, since the resonant frequency of the voltage generating section is set low, the retrace period width becomes long, but this retrace period width, that is, the horizontal pulse width Tr and its amplitude Vr
There is an inversely proportional relationship between the When the retrace period width Tr becomes longer, the horizontal pulse amplitude Vr
becomes smaller. Since the collector loss of the horizontal output transistor is determined by the product of the collector current and the collector voltage, that is, the horizontal pulse voltage at turn-off, when the retrace period width Tr becomes longer and the amplitude of the horizontal pulse becomes smaller, the horizontal output transistor's collector loss increases. Collector loss is reduced. Therefore, in the voltage generating section, the power loss is significantly reduced due to the synergistic effect of the reduction in switching loss due to the low drive frequency of the horizontal output transistor and the reduction in collector loss due to the low resonance frequency. Become.

Moreover, as the retrace period width Tr becomes longer, the pulse width of the horizontal pulse for extracting the anode voltage, etc. becomes larger. This means that the conduction period of each diode that rectifies this pulse increases, so the rectification of this pulse increases. Smoothing also improves the voltage generation efficiency of the voltage generation section that obtains the anode voltage and the like.

Furthermore, in the present invention, the horizontal oscillation frequency obtained from the horizontal oscillation circuit is directly lowered by the frequency down-down circuit, so that the horizontal pulse generated in the horizontal deflection section and the voltage generation section can be easily adjusted without installing a separate correction circuit. There is no time difference between the generated horizontal pulses and therefore no undesirable effects on the screen.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. 1, 1': Horizontal oscillation circuit, 2, 5: Drive circuit, 3: Horizontal deflection section, 4: Frequency down-down circuit, 6:
Voltage generator.

Claims (1)

[Scope of utility model registration request] The horizontal deflection section and the voltage generation section of the horizontal output stage are provided separately, and a frequency step-down circuit is provided that steps down the frequency of the horizontal frequency signal from the horizontal oscillation circuit. , a horizontal deflection coil, and a resonant capacitor; the voltage generating section includes a horizontal output transistor, a flyback transformer, and a resonant capacitor; the horizontal deflection section is driven by a horizontal frequency signal from the horizontal oscillation circuit; is driven by the output signal of the frequency down-converting circuit, and the resonant frequency of the voltage generating section is selected to be lower than the resonant frequency of the horizontal deflection section.