JP2002354280A - Deflection/high voltage integrated type circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the variation of deflection range due to high voltage variation by adding a high voltage stabilizing function and a horizontal deflection current stabilizing function to a deflection/high voltage circuit integrated type circuit. SOLUTION: The integrated type circuit is provided with a high voltage variation detection part for detecting the variation of anode electrode high voltage connected to the secondary winding side of an FBT, a comparison part for comparing the variation of high voltage connected between a high voltage variation detection part and a power supply for a high voltage circuit with reference voltage and an input voltage control part arranged in the high voltage circuit power supply to variably control the input voltage of the primary winding side of the FBT in accordance with the compared result of the comparison part and provided also with an input voltage detection part for detecting the variation of input voltage connected to the primary winding side of the FBT, a voltage shifting part for shifting the changed voltage only by a fixed value by using DC voltage and an addition part for adding the variation voltage shifted from the voltage shifting part to horizontal pin distortion correcting voltage generated from an EW waveform generation part and outputting the added voltage to a PIN output part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection / high voltage circuit used in a TV set using a cathode ray tube, and more particularly to an improvement of a deflection / high voltage integrated circuit in which a deflection circuit and a high voltage circuit are integrated.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a main part of a conventional deflection / high voltage circuit. In the figure, 1 is a power supply for a high-voltage circuit, 2 is a flyback transformer, 3 is a collector pulse generator, and 4 is an EW.
5 is a PIN generator, 6 is a horizontal deflection coil,
It is. HD is a horizontal drive pulse, VD is a vertical drive pulse, HV is an anode voltage, and Vcp is a collector pulse.

[0003] Flyback transformer (hereinafter, FBT) 2
Is supplied with a predetermined DC voltage V1 from the high-voltage circuit power supply 1. Collector pulse generator (hereinafter, Vcp generator)
3 is the input of the horizontal drive pulse HD and the collector pulse Vc
The collector pulse Vcp is supplied to the primary winding of the FBT 2. DC voltage V1 and collector pulse Vc
Due to p, a pulsating current is generated in the primary winding of the FBT 2, and as a result, a high voltage is generated in the secondary winding, and further, the anode voltage HV is generated through the rectifier. Further, the collector pulse Vcp is also supplied to one end of the horizontal deflection coil 6 to generate a deflection current in the horizontal deflection coil 6.

The EW waveform generator 4 generates a correction waveform (EW (East-West) waveform) for correcting horizontal pincushion distortion based on the input vertical drive pulse VD, and generates a PI.
It is supplied to the N output unit 5. The EW waveform is buffered by the PIN output unit 5 and supplied to the other end of the horizontal deflection coil 6. As described above, the high-voltage circuit necessary for driving a cathode ray tube (CRT) and the horizontal deflection circuit are integrally formed by one circuit.

FIG. 5 is a circuit diagram of an embodiment of a conventional deflection / high voltage circuit, and FIGS. 6A to 6D are signal and voltage waveform diagrams at respective points in FIG. In FIG. 5, B + denotes a high-voltage circuit power supply, B1 denotes an EW waveform generator, and B2 denotes Vcp.
A phase comparator B3 corresponding to the generating unit 3 is a horizontal driving unit. M surrounded by a broken line is a diode modulator,
It corresponds to the PIN output unit 5.

In such a configuration, the collector pulse Vcp is subjected to a horizontal drive pulse (horizontal synchronization) as shown in FIGS. Signal) generated as a pulse synchronized with HD. The transistor Tr1 is switched by a pulse from the horizontal drive unit B3 receiving Vcp.

A high voltage circuit power supply B + is input to the primary winding of the FBT, and the transistor T connected to the primary winding is
Due to the switching action of r1, a pulsating current is generated in the primary winding, and a high voltage is generated in the secondary winding. At this time, a half-wave sine wave horizontal retrace pulse is generated on the Vcp line by the transistor Tr1 and the diode modulator M (see FIG. 6C). The peak value of this horizontal retrace pulse is
Since the B + power supply is constant, the voltage is constant, and the anode voltage HV is constant unless there is a load change.

On the other hand, the horizontal deflection coil (HDY) is supplied with a DC power at one end and an output voltage of the buffer A1 (horizontal PIN distortion correction waveform, that is, a vertical period parabolic waveform) at one end. ) Is supplied, and a horizontal deflection current whose PIN distortion has been corrected by the Vcp pulse flows. By the way, in the deflection / high voltage integrated circuit, if the anode voltage HV is constant and the horizontal deflection current is constant, the image on the CRT screen has a constant amplitude and the image is stable. However, a current proportional to the video signal (corresponding to the beam impedance Rb) applied to the cathode of the CRT flows through the HV of the anode voltage. In contrast, in general, FBT
Since the output impedance of the HV terminal is not small enough, the anode voltage (HV) fluctuates as shown in FIG. Due to such a voltage fluctuation, the amplitude of the screen changes depending on the high voltage. In this case, the low HV /
For high, the amplitude is large / small.

[0009]

In order to solve the above-mentioned conventional problems, conventionally, the HV fluctuation is simply accepted or the fluctuation is detected (for example, by using the G terminal current in FIG. 5). For example, a rough video signal can be detected, and therefore, the HV fluctuation can be detected indirectly. Using this, the horizontal deflection current is corrected (for example, the signal S1 (see FIG. 6C)).
To compensate for the change in amplitude on the screen.

However, there is a problem that the display quality is impaired if it is simply allowed as it is. In addition, in the case of correcting with a horizontal deflection current, in a situation where a high-voltage fluctuation actually exists, an independent system (horizontal deflection circuit) is corrected in an open loop, so that the correction becomes excessive, resulting in poor response. There has been a problem that it is difficult to request sufficient accuracy and the design is difficult.

In view of the above problems, an object of the present invention is to add a high voltage stabilization circuit and a horizontal deflection current stabilization circuit to a deflection / high voltage circuit integrated circuit, thereby providing a deflection width caused by a high voltage fluctuation. To reduce the fluctuation of

[0012]

In order to solve the above-mentioned problems, an integrated deflection / high voltage circuit according to the present invention is connected to a secondary winding of a flyback transformer and detects a fluctuation of a high voltage for an anode electrode. A high-voltage fluctuation detection unit, a comparison unit connected between the high-voltage fluctuation detection unit and the high-voltage circuit power supply and comparing the high-voltage fluctuation with a reference voltage, and a flywheel provided in the high-voltage circuit power supply according to the comparison result. An input voltage control unit that variably controls an input voltage on a primary winding side of the back transformer. With such a configuration, high pressure can be stabilized.

An input voltage detecting unit connected to the primary winding of the flyback transformer for detecting a change in input voltage, a DC voltage for shifting the changed voltage by a constant value, and A voltage shift unit that performs a high-voltage stabilization of a high voltage by adding the fluctuating voltage shifted from the voltage shift unit and the horizontal pin distortion correction voltage from the EW waveform generation unit and outputting the same to a PIN output unit. In addition to stabilization, horizontal deflection can be stabilized, and the interaction between high pressure and deflection can be reduced.

[0014] Preferably, the high voltage fluctuation detecting section is composed of two resistors connected in series, and a common contact of the two resistors is connected to the input side of the comparing section. Preferably, the input voltage control unit is connected between the collector and the base, and a transistor having the collector connected to the B + power supply, the emitter connected to the primary winding, and the base connected to the output of the comparison unit. It is composed of the resistor.

More preferably, the input voltage detection section and the voltage shift section are constituted by a constant voltage diode having a cathode connected to the primary winding, and a resistor connected to the anode of the constant voltage diode. And the common contact of the resistor is connected to the adder.

[0016]

FIG. 1 is a block diagram showing a main part of a deflection / high voltage circuit according to the present invention. As shown, the high voltage detector 17 and the reference voltage unit 1 are different from the conventional circuit of FIG.
8, a comparator 19, a DC voltage shifter 20, an adder 21, and the like are added. The high voltage detector 17 has an anode voltage HV
And the detected voltage is input to the comparator 19. Also,
The reference voltage section 18 generates a reference voltage and is input to the comparator 19. The comparator 19 compares the reference voltage with the anode detection voltage, and inputs the comparison result to the high-voltage circuit power supply 11. The output voltage V1 from the high-voltage circuit power supply 11 is supplied to the FBT 12 as well as to the DC voltage shifter 20 and further to the adder 21 as the voltage S2. Further, the output S1 of the EW waveform generator 14 is input to the adder 21, and the addition result of the adder 21 is input to the PIN output unit 15.

FIG. 2 is a circuit diagram of one embodiment of the deflection / high voltage circuit according to the present invention, and FIGS. 3A to 3D are signal and voltage waveform diagrams at respective points in FIG. In FIG.
R is a regulator in the high-voltage circuit power supply 11, D corresponds to the high-voltage detector 17, and S corresponds to the DC voltage shifter 20. Vref corresponds to the reference voltage 18 and A3
Corresponds to the comparator 19, and A2 corresponds to the adder 21.
As described above, B + is a power supply for a high-voltage circuit, and B1 is E
A W waveform generator, B2 is a phase comparator corresponding to the Vcp generator, B3 is a horizontal driver, and M surrounded by a broken line is a diode modulator.

The regulator R comprises a transistor Tr2 and a resistor R4, the high voltage detector D comprises resistors R2 and R3, and the DC voltage shifter S comprises a constant voltage diode D3 and a resistor R1. The high-voltage detector D detects the voltage fluctuation by appropriately dividing the anode voltage HV by the resistors R2 and R3 in order to stabilize the anode voltage HV that receives a load fluctuation due to the video signal. The comparator A3 compares the detection voltage S3 of the high voltage detector D with the reference voltage Vref, and inputs the comparison result to the base of the transistor Tr2. Therefore, the high-voltage input voltage V1 to the primary winding is closed-loop controlled by the high-voltage detector D and the comparator A3, whereby the HV can be stabilized. Although the voltage is appropriately divided by the resistors R2 and R3, three resistors may be connected in series, or a capacitor may be connected in parallel with the resistors.

As described above, since the anode voltage HV can be stabilized by following the load fluctuation of the video signal, as shown by the envelopes of the peak values of the voltage V1 and the pulse Vcp in FIG. The input voltage V1 has a voltage change of the opposite polarity corresponding to the change. If this Vcp is applied to the horizontal deflection coil HDY as it is, the horizontal deflection current undergoes unnecessary modulation. Therefore, in the present invention, a stabilizing circuit described below is further added.

The DC voltage shifter S shifts the voltage fluctuation of the input voltage V1 by an appropriate DC level and generates a detection voltage S2 in which the fluctuation width of the voltage V1 is maintained. The voltage D3 in FIG. 3C is the difference between the voltage V1 and the detection voltage S2. Adder A2
Adds the detected voltage S2 and the horizontal PIN distortion correction signal S1 in a DC manner and inputs the result to the buffer A1. As a result, as the voltage applied to the horizontal deflection coil HDY, a constant voltage (equal to the voltage D3) having the same fluctuation at both ends is applied in terms of DC. Therefore, the horizontal deflection current can be stabilized (constant).

[0021]

As described above, according to the present invention,
In a deflection / high voltage integrated circuit in a TV set using a cathode ray tube, high voltage and horizontal deflection can be stabilized, and the interaction between high voltage and deflection can be eliminated. There is an advantage that fluctuation (distortion) can be effectively suppressed and the design is easy.

[Brief description of the drawings]

FIG. 1 is a main block diagram of a deflection / high voltage circuit according to the present invention.

FIG. 2 is a circuit diagram of one embodiment of a deflection / high voltage circuit according to the present invention.

FIGS. 3A to 3D are signal and voltage waveform diagrams at respective points in FIG.

FIG. 4 is a block diagram of a main part of a conventional deflection / high voltage circuit.

FIG. 5 is a circuit diagram of one embodiment of a conventional deflection / high voltage circuit.

6 (A) to 6 (D) are signal and voltage waveform diagrams at respective points in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Power supply for high voltage circuits 12, FBT ... Flyback transformer 13 ... Collector pulse generation part 14 ... EW waveform generation part 15, M ... PIN output part 16 ... Horizontal deflection coil 17, D ... High voltage detection part 18 ... Reference voltage part 19 , A3 Comparator 20, S DC voltage shifter 21, A2 Adder HD Horizontal drive pulse VD Vertical drive pulse HV Anode voltage Vcp Collector pulse PIN Pincushion distortion

Claims (5)

[Claims] 1. A power supply for at least a high-voltage circuit, a flyback transformer connected to the power supply for the high-voltage circuit and generating a high voltage for an anode electrode, and a collector pulse receiving a horizontal drive pulse and generating a collector pulse in the flyback transformer A generation unit, a horizontal deflection coil for inputting the collector pulse and outputting a horizontal deflection current, an EW waveform generation unit for inputting a vertical drive pulse and outputting a correction signal, and correcting by inputting a sum of a detection voltage and a correction signal PIN to output signal
A deflection / high voltage integrated circuit having an output unit, wherein the high voltage fluctuation detection means is connected to the secondary winding side of the flyback transformer and detects a fluctuation of the high voltage for the anode electrode; Comparing means connected between the high-voltage circuit power supply and comparing the high-voltage variation with a reference voltage; primary winding of the flyback transformer provided in the high-voltage circuit power supply according to the comparison result of the comparing means And an input voltage control means for variably controlling an input voltage on the side. 2. A power supply for at least a high-voltage circuit, a flyback transformer connected to the power supply for the high-voltage circuit and generating a high voltage for an anode electrode, and a collector pulse receiving a horizontal drive pulse and generating a collector pulse in the flyback transformer A generation unit, a horizontal deflection coil for inputting the collector pulse and outputting a horizontal deflection current, an EW waveform generation unit for inputting a vertical drive pulse and outputting a correction signal, and correcting by inputting a sum of a detection voltage and a correction signal PIN to output signal
A deflection / high voltage integrated circuit having an output unit, wherein the high voltage fluctuation detection means is connected to the secondary winding side of the flyback transformer and detects a fluctuation of the high voltage for the anode electrode; Comparing means connected between the high-voltage circuit power supply and comparing the high-voltage variation with a reference voltage; primary winding of the flyback transformer provided in the high-voltage circuit power supply according to the comparison result of the comparing means Input voltage control means for variably controlling the input voltage on the input side; input voltage detection means connected to the primary winding of the flyback transformer for detecting a change in the input voltage; Voltage shift means for shifting by voltage; adding the shifted fluctuation voltage from the voltage shift means and the horizontal pin distortion correction voltage from the EW waveform generation unit; Deflection-pressure integrated circuit comprising adding means for outputting the IN output unit. 3. The high-voltage fluctuation detecting means according to claim 1, wherein the high-voltage fluctuation detecting means comprises two resistors connected in series, and a common contact of the two resistors is connected to an input side of the comparing means. Deflection / high voltage integrated circuit. 4. The input voltage control means includes: a transistor having a collector connected to a B + power supply, an emitter connected to the primary winding, and a base connected to an output side of the comparison means; 3. The deflection / high voltage integrated circuit according to claim 1 or 2, wherein the integrated circuit comprises a resistor connected between the two. 5. The input voltage detecting means and the voltage shifting means are constituted by a constant voltage diode having a cathode connected to the primary winding, and a resistor connected to an anode of the constant voltage diode. 3. The deflection / high voltage integrated circuit according to claim 2, wherein a common contact between the anode side and the resistor is connected to the adding means.