JP2001333393A - Horizontal deflection circuit and television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal deflection circuit that can achieve low power consumption without increasing the dielectric strength of a horizontal deflection current supplying means for supplying a horizontal deflection current to a horizontal deflecting coil and to provide a television receiver having the horizontal deflection circuit. SOLUTION: The video signal converting part 5A of this horizontal deflection circuit 5 eliminates a prescribed number of horizontal scanning lines that are not displayed on a screen among horizontal scanning lines in the effective video area of the vertical scanning period of a video signal TVS1 to be inputted, extends the horizontal blanking period of each horizontal scanning line by allocating time that corresponds to the eliminated horizontal scanning line to the horizontal blanking period of another horizontal scanning line and outputs a video signal TVS2. A synchronizing signal isolating circuit 3 extracts a horizontal synchronizing signal SH2 and a vertical synchronizing signal SV2 from the video signal TVS2. The outputting part 5B of the circuit 5 supplies a saw tooth horizontal deflection current synchronized with the signal SH2 outputted from the circuit 3 to a horizontal deflection york LH.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal deflection circuit and a television receiver having the same.

[0002]

2. Description of the Related Art In recent years, in television receivers,
There is a tendency for larger screens. In addition, the number of horizontal scanning lines on one screen tends to increase for the purpose of improving image quality. further,
A television receiver is also required to be able to display a video signal having a high horizontal scanning frequency, such as a high-vision signal.

A CRT (cathode ray tube) for a television receiver
Is provided with a horizontal deflection yoke and a vertical deflection yoke to deflect the electron beam, a horizontal deflection circuit is supplied with a horizontal deflection current by a horizontal deflection circuit to scan the electron beam horizontally, and the electron beam is vertically scanned. The vertical deflection circuit supplies a vertical deflection current to the vertical deflection coil.

Since the power consumption increases with the increase in the screen size and the number of horizontal scanning lines, lower power consumption is demanded. In particular, since the power consumption of the horizontal deflection circuit is large, it is necessary to reduce the power consumption of the horizontal deflection circuit.

[0005]

In the horizontal deflection circuit, since the switching power of the horizontal deflection current occupies most of the power consumption, the power consumption of the horizontal deflection circuit is required to reduce the power consumption of the horizontal deflection circuit. It is conceivable to increase the voltage to reduce the horizontal deflection current.

The horizontal deflection circuit has a transistor (hereinafter, referred to as a horizontal output transistor) for supplying a horizontal deflection current to a horizontal deflection yoke. At the time of switching of the horizontal output transistor, a large pulse voltage is generated at the collector during the horizontal blanking period. Since this pulse voltage is applied between the collector and the emitter of the horizontal output transistor, it is necessary to make the breakdown voltage between the collector and the emitter of the horizontal output transistor higher than the peak value of the pulse voltage.

Therefore, when the power supply voltage of the horizontal deflection circuit is increased to reduce the horizontal deflection current, the pulse voltage generated at the collector of the horizontal output transistor increases. Therefore, it is necessary to increase the breakdown voltage of the horizontal output transistor, and the cost increases.

Therefore, it is desired to reduce the power consumption of the horizontal deflection circuit without increasing the breakdown voltage of the horizontal output transistor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a horizontal deflection circuit which achieves low power consumption without increasing the withstand voltage of a horizontal deflection current supply means for supplying a horizontal deflection current to a horizontal deflection coil, and a television receiver having the same. Is to provide a machine.

[0010]

Means for Solving the Problems (1) First invention A horizontal deflection circuit according to a first invention has an input means for inputting a video signal, and a validity of a vertical scanning period in the video signal input by the input means. By deleting a predetermined number of horizontal scanning lines that are not displayed on the screen among the horizontal scanning lines in the video area and allocating a time corresponding to the deleted horizontal scanning line to a horizontal blanking period of another horizontal scanning line, each horizontal scanning line is deleted. A video signal converting means for extending the horizontal blanking period of the scanning line, and a horizontal deflection current is supplied to the horizontal deflection coil so that the electron beam is retraced in each horizontal blanking period extended by the video signal converting means. And a horizontal deflection current supply means for supplying.

In the horizontal deflection circuit according to the present invention, a predetermined number of horizontal scanning lines which are not displayed on the screen among the horizontal scanning lines in the effective image area are deleted by the video signal converting means.
Since the time corresponding to the deleted horizontal scanning line is allocated to the horizontal blanking period of another horizontal scanning line, the horizontal blanking period of each horizontal scanning line is extended. The pulse width of the pulse voltage generated in the horizontal deflection coil is extended. Thereby, without increasing the height of the pulse voltage generated in the horizontal deflection coil,
The power supply voltage can be increased. In other words, if the withstand voltage of the horizontal deflection current supply means for supplying the horizontal deflection current to the horizontal deflection coil is the same, a higher power supply voltage can be used. Therefore, the power supply voltage can be increased and the horizontal deflection current can be reduced without increasing the breakdown voltage of the horizontal deflection current supply means, and the power consumption of the horizontal deflection circuit can be reduced without damaging the image on the screen. Can be.

(2) Second invention In the horizontal deflection circuit according to the second invention, in the configuration of the horizontal deflection circuit according to the first invention, the input means performs analog-to-digital conversion and outputs a digital signal. A video signal converting means, the video signal converting means storing a digital signal output from the analog-to-digital converting means, and controlling the writing and reading of the digital signal to and from the storing means, thereby forming a horizontal scanning line in the effective video area. Control means for deleting a predetermined number of horizontal scanning lines which are not displayed on the screen and extending a horizontal blanking period of each horizontal scanning line, and converting the digital signal read from the storage means from digital to analog to analog signal And digital-to-analog conversion means for outputting

In this case, a simple function of controlling the writing and reading of digital signals to and from the storage means by the control means eliminates a predetermined number of horizontal scanning lines which are not displayed on the screen among the horizontal scanning lines in the effective image area, and controls each horizontal scanning line. Since the horizontal blanking period of the scanning line can be extended, the configuration of the horizontal deflection circuit is not complicated.

(3) Third invention A horizontal deflection circuit according to a third invention is the horizontal deflection circuit according to the first or second invention, wherein a predetermined number of horizontal scanning lines are arranged at a start portion of an effective image area. Or the horizontal scanning line at the end of the effective image area.

In this case, horizontal scanning lines outside the upper end of the screen or horizontal scanning lines outside the lower end of the screen are deleted. Therefore, the horizontal scanning lines in the effective image area can be deleted without affecting the image on the screen.

(4) Fourth Invention A television receiver according to a fourth invention is an input means for inputting a video signal, and horizontal scanning of an effective video area in a vertical scanning period in the video signal input by the input means. By deleting a predetermined number of horizontal scanning lines that are not displayed on the screen from the lines and allocating a time corresponding to the deleted horizontal scanning line to a horizontal blanking period of another horizontal scanning line, the horizontal scanning line of each horizontal scanning line is deleted. Video signal converting means for extending the line erasing period, video signal processing means for extracting video information, a horizontal synchronizing signal and a vertical synchronizing signal from the video signal output by the video signal converting means, and a horizontal deflection coil and a vertical deflection coil. A cathode ray tube having a horizontal deflection coil and a vertical deflection coil to scan an electron beam and display an image according to video information output from the video signal processing means; Horizontal deflection current supply means for supplying a horizontal deflection current to a horizontal deflection coil of a cathode ray tube in synchronization with the horizontal synchronization signal output from the video signal processing means; and horizontal and vertical synchronization signals output from the video signal processing means Vertical deflection current supply means for supplying a vertical deflection current to a vertical deflection coil of a cathode ray tube in synchronization with the vertical deflection current.

In the television receiver according to the present invention, a predetermined number of horizontal scanning lines which are not displayed on the screen among the horizontal scanning lines in the effective video area in the vertical scanning period are deleted by the video signal conversion means, and are deleted. The time corresponding to the horizontal scanning line is allocated to the horizontal blanking period of another horizontal scanning line, so that the horizontal blanking period of each horizontal scanning line is extended. , The pulse width of the pulse voltage generated is extended. Thus, the power supply voltage can be increased without increasing the height of the pulse voltage generated in the horizontal deflection coil. In other words, if the withstand voltage of the horizontal deflection current supply means for supplying the horizontal deflection current to the horizontal deflection coil is the same, a higher power supply voltage can be used. Therefore, it is possible to increase the power supply voltage and reduce the power consumption of the horizontal deflection current supply unit without damaging the image on the screen and without increasing the withstand voltage of the horizontal deflection current supply unit.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a television receiver according to one embodiment of the present invention.

The television receiver shown in FIG. 1 has a video signal processing circuit 1, a color signal reproducing circuit 2, a synchronizing signal separating circuit 3, a cathode ray tube (CRT) 4, a horizontal deflection circuit 5, and a high voltage output circuit 6.
And a vertical deflection circuit 7. The cathode ray tube 4 is provided with a horizontal deflection yoke LH and a vertical deflection yoke LV.

The video signal processing circuit 1 separates and outputs a luminance signal and a color difference signal from a video signal TVS2 supplied from a horizontal deflection circuit 5, which will be described later, and outputs the video signal TV.
S2 is given to the synchronization signal separation circuit 3. Color signal reproduction circuit 2
Reproduces a color signal from the luminance signal and the color difference signal output from the video signal processing circuit 1, and outputs the display signal C to the cathode ray tube 4.
Give as. The synchronization signal separation circuit 3 extracts a horizontal synchronization signal SH2 and a vertical synchronization signal SV2 from the video signal TVS2 provided from the video signal processing circuit 1.

The horizontal deflection circuit 5 receives the input video signal T
Video signal converter 5 for converting VS1 to video signal TVS2
A and an output section 5B for supplying a sawtooth-like horizontal deflection current _IH to the horizontal deflection yoke LH in synchronization with the horizontal synchronization signal SH2 output from the synchronization signal separation circuit 3. The configurations and operations of the video signal conversion unit 5A and the output unit 5B will be described later.

The high voltage output circuit 6 includes a high voltage drive circuit, a flyback transformer, a dynamic autofocus control circuit and a dynamic autofocus output circuit, and outputs a high voltage to the cathode ray tube 4 for focus control and the like.

The vertical deflection circuit 7 includes a vertical output circuit,
The horizontal synchronization signal SH2 output from the synchronization signal separation circuit 3.
In addition, in order to deflect the electron beam in the cathode ray tube 4 in the vertical direction in synchronization with the vertical synchronization signal SV2, a sawtooth vertical deflection current _IV is supplied to the vertical deflection yoke LV.

In the present embodiment, the video signal conversion section 5A corresponds to the input means and the video signal conversion means, the output section 5B corresponds to the horizontal deflection current supply means, and the horizontal deflection yoke LH corresponds to the horizontal deflection coil. I do. A video signal processing circuit 1, a color signal reproducing circuit 2, and a synchronizing signal separating circuit 3;
Constitute a video signal processing means, the vertical deflection circuit 7 corresponds to a vertical deflection current supply means, and the vertical deflection yoke LV corresponds to a vertical deflection coil.

FIG. 2 is a diagram showing horizontal scanning lines on the surface of the cathode ray tube 4. FIG. 3 shows the video signal converter 5A of FIG.
FIG. 6 is a waveform chart for explaining conversion of a video signal in the embodiment. FIG. 4 is an enlarged view of a part of the video signal of FIG.

In the NTSC system, the number of horizontal scanning lines in one vertical scanning period is 262.5, of which 240 is the number of horizontal scanning lines in the effective image area (corresponding to a period other than the vertical blanking period), and the number of horizontal scanning lines is 240. The number of horizontal scanning lines during the line erase period is 2
2.5. FIG. 2 shows 240 horizontal scanning lines in the effective image area. The horizontal scanning lines in the effective image area are called effective scanning lines.

Of the horizontal scanning lines in the effective image area, the upper and lower horizontal scanning lines protrude from the screen (the surface of the cathode ray tube 4) 4a. The horizontal scanning line that extends off the screen 4a is called overscan. Screen 4 for overscan
Not displayed in a.

The overscan amount is set to, for example, about 8% of the number of horizontal scanning lines in the effective image area. That is, when the number of horizontal scanning lines in the effective image area is 240, the overscan amount is about 19. FIG.
In the example, the overscan amount outside the upper end of the screen 4a is nine, and the overscan amount outside the lower end of the screen 4a is nine. In the present embodiment, the screen 4a
5 out of the 9 horizontal scan lines outside the top edge of
Five of the nine horizontal scanning lines outside the lower end of the screen 4a are deleted.

FIGS. 3A and 3B show the waveforms of the video signals TVS1 and TVS2 before and after the vertical blanking period. In the present embodiment, it is assumed that the video signal TVS1 is an NTSC video signal.

In the video signal TVS1 input to the video signal converter 5A of FIG. 1, as shown in FIG.
For example, the number of horizontal scanning lines in one vertical scanning period is 262.5.
It is assumed that the number of effective scanning lines is 240 and the vertical scanning frequency is 60 Hz. In this case, the number of horizontal scanning lines existing in the vertical blanking period is 22.5. Here, the effective scanning line is a horizontal scanning line in an effective image area (corresponding to a period other than the vertical blanking period) in the vertical scanning period.

The video signal TVS1 is converted into a video signal TVS2 by the video signal converter 5A of the horizontal deflection circuit 5. In the video signal TVS2, as shown in FIG. 3B, for example, the number of horizontal scanning lines in one vertical scanning period is 25.
2.5, the number of effective scanning lines is 230, and the vertical scanning frequency is 60 Hz. In this case, the number of horizontal scanning lines existing in the vertical blanking period of the video signal TVS2 is 22.5. As described above, in the video signal TVS2, the number of horizontal scanning lines in the vertical blanking period is ten less than the number of horizontal scanning lines in the vertical blanking period of the video signal TVS1.

As shown in FIG. 4A, in the video signal TVS1, the horizontal blanking period (no signal period)
Is about 10 μsec. And the video signal period (horizontal scanning period) is about 53.6 μsec. The horizontal scanning line period including the horizontal blanking period and the video signal period is about 63.
6 μsec. It is. In this case, the horizontal scanning frequency of the video signal TVS1 is 15.734 kHz.

On the other hand, as shown in FIG. 4B, in the video signal TVS2, the horizontal blanking period is about 12.5 μm.
sec. And the video signal period is about 53.6 μsec.
And the horizontal scanning line period is about 66.1 μsec. It is. That is, the horizontal blanking period of the video signal TVS2 is about 2.5 μm longer than the horizontal blanking period of the video signal TVS1.
sec. Has been extended. Thereby, the video signal TVS
2 is approximately 2.5 μsec. Longer than the horizontal scanning line period of the video signal TVS1. It is getting longer. In this case, the horizontal scanning frequency of the video signal TVS2 is 15.734.
× 252.5 / 262.5 = 15.13 kHz.

As described above, a predetermined number, for example, 10 horizontal scanning lines which are not displayed on the screen among the horizontal scanning lines in the effective video area in the vertical scanning period of the video signal TVS1 are deleted, and correspond to the deleted horizontal scanning lines. This time is allocated to the horizontal blanking period of another horizontal scanning line, so that the horizontal blanking period of each horizontal scanning line is extended.

FIG. 5 is a block diagram showing the configuration of the video signal converter 5A. The video signal conversion unit 5A includes a sampling clock generation circuit 11, an analog / digital (A / D)
It includes a converter 12, a video memory 13, a digital / analog (D / A) converter 14, a synchronizing signal separation circuit 15, a video memory write control circuit 16, an expanded horizontal synchronization pulse generation circuit 17, and a video memory read control circuit 18.

The sampling clock generation circuit 11 generates a sampling clock CK having a predetermined frequency. A / D
The converter 12 includes a sampling clock generation circuit 11
Sampling is performed in response to the sampling clock CK output from the device, and the video signal TVS1 is converted into a digital signal. The video memory 13 converts the digital signal output from the A / D converter 12 into a sampling clock CK.
Memorize in response to The D / A converter 14 converts the digital signal read from the video memory 13 into an analog signal in response to the sampling clock CK, and outputs the analog signal as a video signal TVS2.

The synchronizing signal separating circuit 15 outputs the video signal TVS
1, the horizontal synchronization signal SH1 and the vertical synchronization signal SV1 are extracted. The video memory write control circuit 16 controls the A / D converter 1 based on the horizontal synchronization signal SH1 and the vertical synchronization signal SV1 output from the synchronization signal separation circuit 15.
2 is written into the video memory 13.

The expanded horizontal synchronizing pulse generating circuit 17 outputs a horizontal synchronizing signal SH3 having a lower frequency than the horizontal synchronizing signal SH1 and a vertical synchronizing signal SV1 based on the vertical synchronizing signal SV1 output from the synchronizing signal separating circuit 15.
Is output. The frequency of the horizontal synchronization signal SH1 is, for example, 1
The frequency of the horizontal synchronization signal SH3 is, for example, 15.13 kHz.

The video memory read control circuit 18 starts reading digital signals for one vertical scanning period from the video memory 13 in response to the vertical synchronizing signal SV1 output from the expanded horizontal synchronizing pulse generation circuit 17, and performs vertical retrace. After reading out digital signals corresponding to 22.5 horizontal scanning lines in the erasing period, a predetermined number of starting portions of the effective image area, for example, digital signals corresponding to 5 horizontal scanning lines are skipped, and 6 The digital signals corresponding to the first to 235th horizontal scanning lines are sequentially read, and the address signal is read so as to skip a predetermined number of the end portions of the effective image area, for example, the digital signals corresponding to five horizontal scanning lines. This is given to the video memory 13. As a result, the number of horizontal scanning lines in one vertical scanning period of the digital signal read from the video memory 13 is 252.5.

At this time, the video memory read control circuit 1
Reference numeral 8 determines a read timing for each horizontal scan based on the horizontal synchronization signal SH3 output from the expanded horizontal synchronization pulse generation circuit 17. That is, the video memory read control circuit 18 delays the read start timing of the video memory 13 in the horizontal blanking period (no signal period) by a predetermined time. The delay time at that time is the horizontal synchronization signal S
This corresponds to the difference between the cycle of H1 and the cycle of the horizontal synchronization signal SH3, and in the example of FIG. It is. Thereby, the horizontal blanking period is about 12.5 μsec. The digital signal corresponding to each horizontal scanning line is read out in synchronization with the horizontal synchronizing signal SH3.

In this case, the total of the horizontal scanning line periods of the ten deleted horizontal scanning lines is equal to the total of the extended periods of the horizontal blanking period of the remaining 252.5 horizontal scanning lines. Therefore, the vertical scanning frequencies of the video signals TVS1 and TVS2 become equal at 60 Hz.

In the present embodiment, the A / D converter 12 corresponds to an input means and an analog-to-digital conversion means, and includes a video memory 13, a D / A converter 14, a synchronizing signal separation circuit 15, a video memory write control circuit 16, The expanded horizontal synchronizing pulse generation circuit 17 and the video memory read control circuit 18 constitute video signal conversion means. Also,
The video memory 13 corresponds to storage means, the video memory write control circuit 16, the expanded horizontal synchronizing pulse generation circuit 17 and the video memory read control circuit 18 constitute control means, and the D / A converter 14 corresponds to digital-to-analog conversion means. I do.

FIG. 6 is a block diagram showing the configuration of the output section 5B. FIG. 7 is a waveform chart for explaining the operation of the output unit 5B.

The output section 5B includes a horizontal AFC (automatic frequency control) circuit 20, a horizontal oscillation circuit 21, and a horizontal drive circuit 2.
2, horizontal output transistor 23, power supply terminal 24, choke coil 25, damper diode 26, resonance capacitance 27
And an S-shaped correction capacitor 28.

The horizontal AFC circuit 20 prevents the horizontal synchronization signal SH2 output from the synchronization signal separation circuit 3 shown in FIG. Thereby, the stability of the oscillation frequency of the horizontal oscillation circuit 21 described later is improved. The horizontal oscillation circuit 21 includes the horizontal AFC circuit 2
A pulse signal is generated in synchronization with the horizontal synchronizing signal SH2 provided via the signal 0. The horizontal drive circuit 22 amplifies the pulse signal output from the horizontal oscillation circuit 21 to perform waveform shaping, and converts the pulse signal into a horizontal output transistor 23.
Give to the base.

The horizontal output transistor 23 performs switching in response to a pulse signal given from the horizontal drive circuit 22. The emitter of the horizontal output transistor 23 is grounded. The collector of the horizontal output transistor 23 is connected to a power supply terminal 24 via a choke coil 25. The power supply terminal 24 is _supplied with a power supply voltage V _CC .

The cathode of the damper diode 26 is connected to the collector of the horizontal output transistor 23,
The anode is grounded. This damper diode 2
6, a resonance capacitor 27 is connected in parallel. A series circuit of a horizontal deflection yoke LH and an S-shaped correction capacitor 28 is connected between the collector of the horizontal output transistor 23 and the ground terminal.

In this embodiment, the horizontal output transistor 23 corresponds to horizontal deflection current supply means.

FIG. 7A shows the video signal TVS2, and FIG. 7B shows the horizontal deflection current I flowing through the horizontal deflection yoke LH.
_H , and FIG. 7C shows a horizontal deflection pulse voltage V _C generated at the collector of the horizontal output transistor 23.

[0050] in synchronization with the horizontal synchronizing signal SH2 of the video signal TVS2 shown in FIG. 7 (a), the horizontal AFC circuit 20, the pulse voltage V _B to the base of horizontal output transistor 23 by the horizontal oscillation circuit 21 and the horizontal drive circuit 22 The switching operation of the horizontal output transistor 23 is performed. By the action of the switching operation and the damper diode 26 and resonant capacitor 27 of the horizontal output transistor 23, sawtooth horizontal deflection current I _H shown in FIG. 7 (b) flows to the horizontal deflection yoke LH. Peak value i _p of the horizontal deflection current I _H is given by the following equation.

I_p = W / (t_s× V_CC(1) where w is the horizontal deflection sensitivity (unit) of the horizontal deflection yoke LH.
Is HA^Two ) And t _s Is the horizontal deflection current I_HHorizontal scanning
Period (unit: seconds), V_CCIs the power supply of the horizontal deflection circuit 5
Voltage (unit is volt). In the above equation (1)
Horizontal deflection sensitivity w and horizontal scanning period t_sIs the deflection yoke
It is constant if the system and the scanning method are the same. I
Therefore, the power supply voltage V_CCBy increasing the horizontal deflection
Current I_HPeak value i_pCan be reduced
I understand.

[0052] peak value V _p of the horizontal deflection pulse voltage V _C generated in the collector of the horizontal output transistor 23 by passing a horizontal deflection current I _H to the horizontal deflection yoke LH shown in FIG. 7 (b) is given by: .

[0053] _{V p = {(π / 2} ) × (t s / t r) +1} × V CC ... (2) where, t _r is the horizontal blanking period, the horizontal deflection pulse voltage V _C It corresponds to the pulse width. From the above equation (2), the higher the power supply voltage V _CC is, it can be seen that the peak value V _p of the horizontal deflection pulse voltage V _C increases. Peak value V _p of the horizontal deflection pulse voltage V _C is applied between the collector and emitter of the horizontal output transistor 23 of FIG.

However, the horizontal output transistor 23
It can not be applied in the peak value V _p of the pressure specification more horizontal deflection pulse voltage V _C between the collector and emitter between the collector and emitter. Thus, under the constraint that the peak value V _p of the horizontal deflection pulse voltage V _C does not exceed the breakdown voltage specifications of the collector-emitter of the horizontal output transistor 23, the power supply in order to reduce the peak value i _p of the horizontal deflection current I _H It is necessary to increase the voltage V _CC .

It can be seen from the above equation (2) that the ratio t _s / t _r between the horizontal scanning period t _s and the horizontal blanking period t _r should be reduced. In this embodiment, the video horizontal blanking interval t _r of the video signal TVS2 signal TVS1
About 0.61μsec than of the horizontal blanking period t _r.
By extending, the ratio t _s / t _r is reduced.

The power supply voltage V _{CC is set} to 100 V, and the video signal T
T _s = 53.6 [μsec in VS1. ] And t
_r = 10 [μsec. Substituting the above equation (2)], the peak value V _p of the horizontal deflection pulse voltage V _C is given by the following equation.

V _p = ｛(π / 2) × 53.6 / 10) +
1｝ × 100 = 942 [V] Next, the horizontal deflection sensitivity w is set to 30 mHA ^2, and t _s = 5.
3.6 [μsec. ] And V _cc = 100 by the above equation (1)
Substituting the peak value i _p of the horizontal deflection current I _H is expressed by the following equation.

I _p = {30 / (53.6 × 100)} ×
10 ³ = 5.60 [A _pp ] Next, the above equation (2) is modified to obtain the following equation.

V_CC= V_p/ ｛(Π / 2) × (t_s/ T_r) +1｝ (3) In equation (3), V_p= 942 [V], to the video signal TVS2
T_s= 53.6 [μsec. ] And t_r= 1
2.5 [μsec. ], The power supply voltage V _CCIs next
It looks like an expression.

V _CC = 942 / [(π / 2) × 53.6 /
12.5) +1] = 121.8 [V ] Accordingly, the peak value i _p of the horizontal deflection current I _H is expressed by the following equation from the above equation (1).

I _p = 30 / (53.6 × 121.8) =
4.60 [A _pp ] As described above, by increasing the pulse width (horizontal blanking period) of the horizontal deflection pulse voltage V _C , the breakdown voltage between the collector and the emitter of the horizontal output transistor 23 can be increased. the peak value i _p of the horizontal deflection current I _H 5.60
It can be reduced from A _pp to 4.60A _pp. Thereby, the power consumed by the horizontal deflection circuit 5 can be reduced.

According to the television receiver of this embodiment, the video memory 13, the D / A converter 14, the synchronization signal separation circuit 15, the video memory write control circuit 16, the expanded horizontal synchronization pulse generation circuit 17, and the video memory read Since the horizontal blanking period is extended by the control circuit 18, the horizontal output transistor 2 is turned on during the horizontal blanking period.
3 can extend the pulse width of the horizontal deflection pulse voltage V _C generated at the collector. Thereby, without increasing the peak value V _p of the horizontal deflection pulse voltage V _C, the horizontal deflection current I by increasing the power supply voltage V _CC of the horizontal deflection circuit 5
It is possible to reduce the peak value i _p of _H. Accordingly, without increasing the breakdown voltage between the collector and emitter of the horizontal deflection current I _H for supplying the horizontal output transistor 23 to the horizontal deflection yoke LH, it is possible to reduce the power consumption of the horizontal deflection circuit 5.

In the above embodiment, a composite signal including a luminance signal and a color difference signal has been described as an example of a video signal. However, for example, a component signal is used, and a plurality of video signal converters are used to output a component signal. May be configured to perform the conversion.

In the above-described embodiment, the horizontal synchronization signal and the vertical synchronization signal are stored in the video memory 13 together with the video information. The horizontal synchronization signal and the vertical synchronization signal may be generated, and the video information stored in the video memory and the horizontal synchronization signal and the vertical synchronization signal may be combined later.

[0065]

According to the present invention, a predetermined number of horizontal scanning lines which are not displayed on the screen among the horizontal scanning lines in the effective image area during the vertical scanning period are deleted, and the time corresponding to the deleted horizontal scanning lines is reduced. Is assigned to the horizontal blanking period of the horizontal scanning line, the horizontal blanking period of each horizontal scanning line is extended, so that the pulse width of the pulse voltage generated in the horizontal deflection coil during the horizontal blanking period is reduced. It is extended. Thus, the power supply voltage can be increased without increasing the height of the pulse voltage generated in the horizontal deflection coil. Therefore, the power supply voltage can be increased and the horizontal deflection current can be reduced without increasing the withstand voltage of the horizontal deflection current supply unit that supplies the horizontal deflection current to the horizontal deflection coil. As a result, it is possible to reduce the power consumption of the horizontal deflection circuit without damaging the image on the screen.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a television receiver according to an embodiment of the present invention.

FIG. 2 is a diagram showing horizontal scanning lines on the surface of a cathode ray tube.

FIG. 3 is a waveform chart for explaining conversion of a video signal in the video signal conversion unit of FIG. 1;

FIG. 4 is an enlarged view of a part of the video signal of FIG. 3;

FIG. 5 is a block diagram showing a configuration of a video signal converter of the horizontal deflection circuit of FIG. 1;

FIG. 6 is a block diagram showing a configuration of an output unit of the horizontal deflection circuit of FIG. 1;

FIG. 7 is a waveform chart for explaining the operation of the output unit in FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 video signal processing circuit 2 color signal reproduction circuit 3 synchronization signal separation circuit 4 cathode ray tube 5 horizontal deflection circuit 5A video signal conversion unit 5B output unit 7 vertical deflection circuit 11 sampling clock generation circuit 12 A / D converter 13 video memory 14 D / A converter 16 Video memory write control circuit 17 Extended horizontal synchronization pulse generation circuit 18 Video memory read control circuit LH Horizontal deflection yoke LV Vertical deflection yoke

Claims (4)

[Claims] An input means for inputting a video signal, and a predetermined number of horizontal scanning lines which are not displayed on a screen among horizontal scanning lines in an effective video area in a vertical scanning period in a video signal input by the input means are deleted. Video signal converting means for extending a horizontal blanking period of each horizontal scanning line by allocating a time corresponding to the deleted horizontal scanning line to a horizontal blanking period of another horizontal scanning line; and A horizontal deflection current supply means for supplying a horizontal deflection current to a horizontal deflection coil so that the electron beam is retraced in each horizontal blanking period extended by the means. 2. The input means includes analog-to-digital conversion means for converting a video signal from analog to digital to output a digital signal, wherein the video signal conversion means stores a digital signal output from the analog-to-digital conversion means. By controlling the writing and reading of digital signals to and from the storage means, the predetermined number of horizontal scanning lines that are not displayed on the screen among the horizontal scanning lines in the effective image area are deleted, and 2. The control method according to claim 1, further comprising: a control unit that extends a horizontal blanking period; and a digital-to-analog conversion unit that performs digital-to-analog conversion of the digital signal read from the storage unit and outputs an analog signal. Horizontal deflection circuit. 3. The horizontal scanning line according to claim 1, wherein the predetermined number of horizontal scanning lines is a horizontal scanning line at a start portion of the effective video area or a horizontal scanning line at an end portion of the effective video area. Horizontal deflection circuit. 4. An input means for inputting a video signal, wherein a predetermined number of horizontal scanning lines which are not displayed on a screen among horizontal scanning lines in an effective video area in a vertical scanning period in the video signal input by the input means are deleted. Video signal converting means for extending a horizontal blanking period of each horizontal scanning line by allocating a time corresponding to the deleted horizontal scanning line to a horizontal blanking period of another horizontal scanning line; and Video signal processing means for extracting video information, a horizontal synchronizing signal and a vertical synchronizing signal from the video signal output by the means, and a horizontal deflection coil and a vertical deflection coil, and the electron beam is generated by the horizontal deflection coil and the vertical deflection coil. A cathode ray tube for scanning and displaying an image in accordance with the video information output from the video signal processing means; A horizontal deflection current supply unit that supplies a horizontal deflection current to the horizontal deflection coil of the cathode ray tube in synchronization with the horizontal synchronization signal, and a horizontal synchronization signal and a vertical synchronization signal output from the video signal processing unit. A vertical deflection current supply means for supplying a vertical deflection current to the vertical deflection coil of the cathode ray tube.