KR950010736B1 - Aspect ration converting apparatus - Google Patents

Abstract

The aspect ratio converting device for a television receiver set having a horizontal oscillator for generating a horizontal driving pulse for a high voltage and deflection driving; a high voltage driving unit for inputting the horizontal driving pulse and supplying driving current for a high voltage output; and a high voltage output unit for inputting the high voltage driving current and supplying a power to a Braun tube having a horizontal deflection coil, comprises a boost up voltage selecting unit for inputting a control signal according to the change of the aspect ratio and controlling a boost up unit to select a boost up voltage according to the aspect ratio; the boost up unit for inputting the voltage control signal and a power supply voltage and controlling a deflection output unit to output deflection current adequate to the selected aspect ratio; and a deflection output unit for inputting the horizontal driving pulse, making the deflection current flow to the deflection coil and increasing or decreasing the current flowing to the deflection coil according to the selected aspect ratio under the control of the boost up unit.

Description

Aspect ratio converter of TV receiver

1 is a block diagram of an aspect ratio conversion apparatus of a conventional television receiver.

2 is a block diagram of an aspect ratio converting apparatus of the present invention.

3 is a CRT deflection current waveform diagram according to an apparatus of the present invention.

4 is a circuit diagram of a first embodiment of an aspect ratio converting apparatus of the present invention.

5 is a circuit diagram of a second embodiment of an aspect ratio converting apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

13: horizontal oscillation unit 14: high pressure drive unit

15: CRT tube 16: high pressure output unit

17: deflection driving unit 18: deflection coil

19: deflection output unit 20: boost-up voltage selector

21: boost-up part 22: power supply

The present invention relates to an apparatus for converting an aspect ratio of a 16: 9 image and an aspect ratio 4: 3 image from a wide screen television (HDTV) receiver through a deflection current level control.

In the conventional WSTV receiver, referring to FIG. 1, the apparatus for converting an aspect ratio includes an image processor 2 for performing channel selection, intermediate frequency amplification, and image detection of a broadcast signal received by the antenna 1, and digitally converting the image signal. An A / D converter 3 for converting into a signal, a line memory 4 for reading / writing the digital video signal, a D / A converter 5 for converting the stored digital video signal into an analog signal, A clock generator 6 for supplying the A / D and D / A conversion clocks and a memory read / write clock, an aspect ratio switching switch 7 for selectively supplying and controlling the clock according to an aspect ratio, and the D / A conversion An image amplifier 9 for amplifying the analog video signal and supplying it to the CRT 8, a deflection processing unit 11 for flowing a deflection current to the deflection coil 10 of the CRT 8 in response to the analog video signal; From the output of the deflection processing section 11 Lai back creating a pulse consists of a video display high-pressure generating section 12 for supplying a high voltage necessary for cathode ray tube (8), whereby the aspect ratio conversion operation in accordance with the following:

In the broadcast signal received by the antenna 1, a channel is tuned by the image processing unit 2, and the video signal of the tuned channel is converted to an intermediate frequency and amplified to detect the video signal, and then the analog video signal is converted into an A / D converter ( 3) is supplied.

The A / D converter 3 converts the input analog video signal into a digital video signal in accordance with an 18 MHz memory write clock NMR supplied from the clock generator 6, and the digital video signal is converted into a memory light clock (MWR). ) Is stored in the line memory 4 in units of one horizontal period (1H).

The memorized video signal is read by the memory lead clock (MRD). When the 16: 9 aspect ratio is outputted, the aspect ratio changeover switch 7 selects the 18 MHz clock of the clock generator 6, and the aspect ratio 4: 3 image outputs. Select 24 MHz clock.

Therefore, when outputting an image with a 16: 9 aspect ratio, an 18 MHz clock, which is the same as the memory write clock MWR, is supplied to the line memory 4 as the read clock MRD, and the video signal is read. The A converter 5 converts the analog video signal to a clock of 18 MHz.

On the other hand, in the 4: 3 aspect ratio video output, a 24 MHz clock faster than the memory write clock (18 MHz) is supplied to the line memory 4 as a read clock (MRD) so that the video signal is read and the read video signal is read. Is converted into an analog video signal in accordance with a clock of 24 MHz in the D / A converter 5.

In other words, when 4: 3 video output is performed, the video signal time-compressed by 4: 3 (= 12: 9) is outputted by performing a memory read at a faster speed than the 16: 9 video output. : Images of three screens can be displayed.

In this way, the analog video signal output from the D / A converter 5 is amplified by the video amplifier 9 and supplied to the CRT 8, and the deflection processor 11 supplies a deflection current to the deflection coil 10. The high voltage generating unit 12 supplies the high voltage necessary for displaying images to the CRT 8 to reproduce the image signal.

However, the aspect ratio converting apparatus through time compression has the following problems.

First of all, the digital signal processing system required for supply and selection of clocks, A / D and D / A conversion, etc. becomes complicated for time compression, and after the blacking period when the aspect ratio is converted to 4: 3 (the section where the beam current is zero). Is increased from about 25% to 45%, so the brightness and contrast are reduced and the resolution is weakened. Even though the aspect ratio is changed to 4: 3, the deflection current is fully deflected at 16: 9. Because of this, unnecessary deflection power consumption is caused unless a blacking section that is as wide as compressed is used as a picture out picture (POP).

The present invention eliminates the above-mentioned time compression method and adjusts the deflection current itself according to the aspect ratio conversion mode to increase / decrease the aspect ratio to perform aspect ratio conversion, simplifying circuit configuration, image brightness, and the like. An object of the present invention is to provide an aspect ratio converting apparatus for a television receiver capable of preventing contrast reduction and reducing power consumption of a deflection. The configuration and operation effects of the apparatus of the present invention will be described below with reference to the accompanying drawings.

First, referring to FIG. 2, the aspect ratio converting apparatus of the present invention includes a horizontal oscillation unit 13 for generating a driving pulse of a horizontal period for high pressure and deflection driving, and a driving current for the high voltage output by receiving the horizontal driving pulse. The high-pressure driving unit 14 for supplying the high-voltage driving unit and the high-voltage output unit 16 for supplying power for displaying an image to the CRT 15 by receiving the high-voltage driving current, and the horizontal driving pulse to receive a horizontal deflection drive A deflection driver 17 for performing a deflection driving pulse, a deflection output unit 19 for supplying a deflection current to the horizontal deflection coil 18, and a boost for selecting a boost-up voltage according to aspect ratio switching. A boost-up unit 21 for controlling the deflection output unit 19 to supply a deflection current suitable for the aspect ratio under the control of the up-voltage selector 20 and the boost-up voltage selector 20, and the high-voltage output. (16), deflection drive And a power supply unit 22 for supplying power to the unit 17 and the boost-up unit 21.

The aspect ratio conversion device operation of the present invention configured as described above is as follows.

The horizontal oscillator 13 generates pulses of the horizontal period 1H necessary for the high pressure driving and the deflection driving, and supplies them to the high pressure driving unit 14 and the deflection driving unit 17 as driving pulses.

The high voltage driving unit 14 converts the input driving pulse into a driving current capable of switching the high voltage output unit 16 and supplies the same to the high voltage output unit 16. Accordingly, the high voltage output unit 16 converts the input driving pulse into the high voltage output unit 16. Rectifies and smoothes the flyback pulse generated during the return period by switching operation, and supplies the smoothed power to the CRT 15 to supply the high pressure and focus required for the electron beam to be scanned on the screen, and to operate the screen, heater, and CRT. To supply.

Meanwhile, at this time, the power supply unit 22 rectifies and smoothes the commercial AC power as a switching mode power supply circuit (SMPS) to supply the stabilized power supply (B +) to the high voltage output unit (16), the deflection driving unit (17), and the boost-up unit. It also supplies a stabilized power source (B +) to (21).

The deflection driver 17 converts the driving pulse supplied from the horizontal oscillation unit 13 into a current required for the deflection output to drive the deflection output unit 19 for switching, and the deflection output unit 19 drives the deflection driver 17. By the deflection current flows to the horizontal deflection coil 18, the image is represented.

Meanwhile, the boost-up voltage selector 20 controls the boost-up unit 21 according to the aspect ratio conversion control signal MODE, and the boost-up unit 21 is controlled by the boost-up voltage selector 20. ) Increases / decreases the power supply B + supplied to the deflection output unit 19 to a deflection current level suitable for each aspect ratio.

Correspondingly, the deflection output unit 19 adds or subtracts a deflection current level flowing to the horizontal deflection coil 18 so as to achieve a horizontal deflection for each aspect ratio.

That is, when the aspect ratio conversion control signal MODE is applied as a low signal when the screen is 16: 9 and high when the screen is 4: 3, the boost-up voltage selector 20 which receives the signal is the boost-up unit 21. In the case of controlling the 16: 9 screen, the boosted-up voltage is increased to supply the increased boost-up voltage to the deflection output unit 19, thereby flowing an increased deflection current for the 16: 9 screen (see FIG. 3). In the case of 4: 3 screen, the boost up voltage is reduced to supply the reduced boost up voltage to the deflection output unit 19, thereby flowing the reduced deflection current according to 4: 3 screen. (See Figure 3)

In this way, in the case of 4: 3 screen, the image displayed on the CRT 15 is compressed to the aspect ratio 4: 3 (= 12: 9) due to the reduced horizontal deflection current.

FIG. 3 shows the waveform of the horizontal deflection current which is varied as described above. When the aspect ratio is changed from 16: 9 to 4: 3, the main picture width needs to be reduced by 25%, and the reduction amount for S-shaped correction is considered. The actual deflection current reduction is 18%.

Therefore, the inductance of the horizontal deflection coil in a circuit operating at 2f _H (f _H : horizontal frequency); L = 35 μH, horizontal retrace range; Required voltage for 6 μsec, deflection current 10.6 A _PP ; V = 35μH × (10.6A _{PP /} 25.78μsec) ≒ 144V, which is the boost of the boost-up section 21 supplied to the deflection output section 19 when the 144V voltage is fully deflected to 16: 9 screen. If the output voltage is the up voltage and the output power source B + of the power supply unit 22 is 110V, 144V is supplied when 34V is boosted up.

On the other hand, 4: required supply voltage when converted to three screens; V = 350 μH × (8.7 A _PP /25.78 μsec) ≒ 118 V. Therefore, in this case, 8 V must be boosted to supply 118 V to the deflection output unit 19. As described above, the boost-up voltage is supplied under the control of the boost-up voltage selector 20 by the boost-up unit 21, and thus the aspect ratio conversion is performed by adjusting the horizontal deflection current.

4 shows a circuit configuration of the first embodiment of the present invention.

In this circuit, the high voltage output section 16 includes a switching transistor Q1 switched by a driving pulse of the high voltage driving section 14, a damper diode D1 and a resonant capacitor C2 of high voltage output, and each circuit section. Flyback transformer (T1) for power supply, rectifier diode (D2) and smoothing capacitor (C3) for supplying CRT drive power, condenser (C1) for stabilization of high voltage output power, and flyback transformer (T1) The rectifier diode (D3), the smoothing capacitor (4) and the resistor (R3) for supplying power to the boost-up voltage selector 20 on the secondary side of the), the deflection output unit 19 is a deflection driver ( The horizontal output transistor Q2 switched by the driving pulse of 17), the deflection coil L1 through which the deflection current by the horizontal output transistor Q2 flows, the damper diode D4 of the deflection output, and the S correction Condenser (C8) and diode (D5) for raster correction It consists of a coil L2, a capacitor C7, C9, and a diode D5. In addition, the boost-up voltage selector 20 is turned on / off by the input aspect ratio control control signal MODE and the transistor Q3 is turned on / off by the boost-up unit 21. The booster 21 is configured to change a boost-up voltage, and the boost-up unit 21 is configured to change a winding ratio according to the relay RL1 on / off, so that the boost-up voltage 19 corresponds to a boost-up voltage. A boost up transformer (T2) and a capacitor (C01) to be supplied to the same, a smoothing capacitor (C5) to supply the boost-up power supply, and a reverse current prevention diode (D6).

In FIG. 4, reference numerals R1, R2, and R4 are resistors.

The circuit diagram of the first embodiment of the present invention configured as described above is as follows.

The switching transistor Q1 is turned on / off by the driving pulse of the high voltage driver 14, and the switching transistor Q1 is turned on and off by the switching operation of the damper diode D1 and the resonant capacitor C2. The scan current flows and a flyback pulse is generated by the flyback transformer T1 and the resonant capacitor C2 during the return period.

The voltage induced by the flyback transformer T1 is supplied to the CRT, the focus stage, the screen stage, the heater, and the like, rectified by the diode D2 and smoothed by the capacitor C3 to supply the CRT driving circuit power, and the diode D3. The power rectified by the capacitor and smoothed by the capacitor C4 is supplied to the relay RL1 through the resistor R3. The power required for the high voltage output is applied to the stable power source B + output from the power supply unit 22 via the smoothing capacitor C1, and the power source that is stepped down through the resistor R1 is the operating power source of the high voltage drive unit 14. Is supplied.

On the other hand, the horizontal output transistor Q2 of the deflection output unit 19 is turned on / off by the driving pulse of the deflection driver 17, and is connected to the on / off of the transistor Q2 to energize the damper diode D4. According to the charge / discharge operation, a deflection current of a sawtooth wave flows through the deflection coil L1.

At this time, the capacitor C6 corrects the S curve of the deflection current to ensure deflection linearity, and the coil L2, the diode D5, and the capacitor C7 and C9 perform raster correction of the deflection current.

The operating power of the deflection driving unit 17 is supplied with the output power B + of the power supply unit 22 stepped down through the resistor R2, and the operating power of the deflection output unit 19 controls the boost-up unit 21. The current flowing through the deflection coil L1 varies depending on the aspect ratio.

That is, in the case of the 16: 9 screen, the aspect ratio conversion control signal MODE is inputted as a low signal, so that the transistor Q3 is turned off and the relay RL1 is also turned off. When the relay RL1 is turned off, the boost up transformer ( The three windings N1, N2 and N3 of T2 are connected in series.

Since the output power B + of the power supply unit 22 is applied to the connection terminal of the windings N1 and N2 through the capacitor C5 and the reverse current prevention diode D6 of the boost-up voltage, it is applied to the deflection coil L1. The power supply voltage is boosted by the winding ratio of the dummy transformer T2 and supplied to the power supply B + at a voltage charged in the capacitor C10.

That is, a boost-up voltage determined by (N1 + N2) / (N1 + N2 + N3) × (B +) × ŋ (where л is the boost-up trans efficiency) is supplied to the 16: 9 screen as shown in FIG. A corresponding deflection current flows, wherein the three windings N1 (N2) N3 of the boost-up transformer T2 are continuous coils and their respective turns ratios are determined by the voltages boosted up as described above.

On the other hand, in the case of 4: 3 screen, since the aspect ratio conversion control signal MODE is input as a high signal, the transistor Q3 is turned on so that the relay RL1 is turned on. Thus, when the relay RL1 is turned on, the boost-up transformer ( The winding N2 of T2) is shorted.

Therefore, the boost-up voltage supplied in this case is reduced and supplied to the voltage determined as N3 (N1 + N2 + N3) × (B +) × ŋ, so that the deflection current corresponding to 4: 3 screen as shown in FIG. Shed.

5 shows a circuit configuration of a second embodiment of the device of the present invention.

In this circuit, since the high voltage output section 16 and the deflection output section 19 perform the same configuration and operation as in the first embodiment, the same parts are denoted by the same reference numerals.

However, in the second embodiment of the present invention, the boost-up voltage selector 20 includes transistors Q4 and Q5 which are turned on and off in opposition to each other by the aspect ratio conversion control signal MODE, and the transistor Q4. It is composed of a relay (RL2) (RL3) to be turned on / off by (Q5) to convert the boost-up voltage of the boost-up section 21, the boost-up section 21 by the relay (RL2) (RL3) A boost-up transformer T3 and a capacitor C10 for supplying a boost-up voltage corresponding to the aspect ratio to the deflection output unit 19 by the boost-up operation on / off, and a smoothing capacitor C5 for supplying the boost-up power supply. And a reverse current prevention diode D6.

The operation of the second embodiment of the present invention configured as described above is as follows.

Since the aspect ratio conversion control signal MODE is input as a low signal in the case of a 16: 9 screen, the transistor Q4 is turned on, the transistor Q5 is turned off, the relay RL2 is turned on, and the relay RL3 is turned off. Therefore, the windings N1 and N2 of the boost-up transformer T3 are connected in series, and the boost-up voltage determined by the winding ratio N2 / (N1 + N2) is charged to the capacitor C10 and the power supply B + As the power is boosted to the deflection coil L1 by being superimposed on the voltage, the deflection current suitable for the 16: 9 screen is flowed as shown in FIG. In other cases, the aspect ratio conversion control signal MODE is input as a high signal in the case of 4: 3 screen, so the transistor Q4 is turned off, the transistor Q5 is turned on, the relay RL2 is turned off, and the relay RL3 is turned on. Comes on. Therefore, since the winding N2 of the boost-up transformer T3 is separated from the main winding 1, it does not generate a boost-up voltage, and the capacitor C5 and the reverse current prevention diodes D6 and C10 of the boost-up voltage are prevented. In addition, since it is separated from the deflection output unit 19, the output power source B + of the power supply unit 22 is directly applied to the deflection coil L1 through the relay RL3 and the winding N1, so as in FIG. The deflection current of the screen is reduced to the screen.

As described above, the screen through time compression excludes conversion and performs aspect ratio conversion through deflection current control, thereby simplifying circuit configuration, and reducing deflection current during 4: 3 screen, thereby reducing deflection power. It is possible to reduce, and to reduce the luminance due to the increase in the blanking period of the conventional video signal.

Claims (3)

Horizontal oscillation unit 13 for generating a drive pulse of a horizontal period for high pressure and deflection drive, and a high-voltage drive unit 14 for supplying a drive current for high voltage output by receiving the horizontal drive pulses output from the horizontal oscillation unit 13 And a high voltage output unit 16 that receives the high voltage driving current output from the high voltage driver 14 and supplies power to the CRT 15 including the horizontal deflection coil 18 to express an image. In a television receiver circuit including a deflection driver 17 for receiving a horizontal driver's output output from the oscillator 13 and performing horizontal deflection driving, a control signal MODE according to aspect ratio conversion is received and different from the aspect ratio. The boost-up voltage selector 20 which controls the boost-up unit 21 to select the boost-up voltage, the voltage control signal of the boost-up voltage selector 20, and the power supply B + voltage are respectively received. line The boost-up unit 21 controls the deflection output unit 19 to output the deflection current corresponding to the aspect ratio, and the horizontal driving pulse output from the deflection driver 17 receives the deflection current to the deflection coil 18. Under the control of the boost-up unit 21, and characterized in that it comprises a deflection output unit 19 for increasing or decreasing the amount of current flowing in the deflection coil in accordance with the selected aspect ratio. The aspect ratio converter of the TV receiver. The booster voltage selector 20 of claim 1, wherein the boost-up voltage selector 20 is turned on / off by an input aspect ratio control control signal MODE and boosted by being turned on / off by the transistor Q3. The relay RL1 converts the boost-up voltage of the up part 21. The boost-up part 21 deflects the boost-up voltage whose winding ratio corresponds to the aspect ratio according to the relay RL1 on / off. An aspect ratio converting apparatus for a television receiver comprising a boost-up transformer (T2) and a capacitor (C10) supplied to a unit (19), a smoothing capacitor (C5) and a reverse current prevention diode (D6) for supplying the boost-up power supply. 2. The transistor according to claim 1, wherein the boost-up voltage selector (20) includes transistors (Q4) (Q5) and (Q4) (Q5) that are turned on and off in opposition to each other by an aspect ratio conversion control signal (MODE). It is configured by the relay (RL2) (RL3) to be turned on / off by the boost-up unit 21 to change the boost-up voltage, the boost-up unit 21 is a boost-up operation by the relay (RL2) (RL3) The boost-up transformer T3 and the capacitor C10 that turn on / off the boost-up voltage corresponding to the aspect ratio to the deflection output unit 19, the smoothing capacitor C5 and the reverse current that supply the boost-up power supply. Aspect ratio converter of television receiver composed of prevention diode (D6).