JPH03100592A - Crt display device - Google Patents

Abstract

PURPOSE:To eliminate the irregularities of an image by performing a switching operation synchronized with horizontal oscillation output for both a low voltage output power source and a high voltage output power source. CONSTITUTION:The output of a horizontal oscillation circuit 5 is supplied to a horizontal output circuit 6 and the transistor 29 of the low voltage output power source 2, and the output of the transistor 29 is applied to the trigger input terminal of an oscillator 27 with a transformer 28, and the output of the oscillator 27 is synchronized with the horizontal oscillation output, and the output pulse of the low voltage output power source 2 is synchronized with the horizontal oscillation output. An output voltage is supplied from a tertiary winding provided at the output transformer 24 of the low voltage output power source 2 to the base of the output transistor 33 of the high voltage output power source 3, and output is generated at the high voltage output power source 3 similarly as in the low voltage output power source 2, and the output transistors 23, 33 are energized or deenergized simultaneously, and the output synchronized with the horizontal oscillation output are issued from them. In such a way, it is possible to stably display the image without the irregularities due to a noise.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a CRT display device used in a combiator terminal, particularly to a power supply device.

BACKGROUND OF THE INVENTION This type of device uses a so-called switching power supply circuit (or switching generator) in which a rectified voltage is converted into a high-frequency alternating current by switching and then rectified to obtain a direct current. In order to avoid noise generated by power supply switching from disturbing the horizontal period, conventionally the horizontal output pulse is used as a trigger to synchronize switching.

Furthermore, a low voltage output power source is sometimes used as a power source for circuits other than the horizontal output circuit, but in this case, switching is free-running because it cannot be triggered by a horizontal output pulse. The reason is that if the horizontal output circuit or its power supply fails, the horizontal output pulse will not be generated, so if that pulse triggers the low voltage output power supply, that power supply will also not work properly and the entire device will fail. It is from. Therefore, the switching noise generated by the low voltage output TL source is not synchronized with the horizontal output circuit.

Problems to be Solved by the Invention As described above, in conventional CRT display devices, there is a problem in that the noise generated by the low voltage output power source is not synchronized with the horizontal output circuit and disturbs the operation of the horizontal oscillation circuit and the horizontal output circuit. It existed.

In view of the above problems, the present invention attempts to eliminate image disturbances caused by disturbances in the horizontal output circuit.

Means for Solving the Problems The CRT display device of the present invention includes means for triggering a low voltage output power supply with a horizontal oscillation output signal and means for triggering a high voltage output power supply using an output pulse of the low voltage output power supply. establish.

OPERATION By means of the above-described means, the CRT display device of the present invention performs switching operations in synchronization with the horizontal oscillation output for both the low voltage output power source and the high voltage output power source. Therefore, it is possible to eliminate image blur.

Embodiment FIG. 1 shows a block diagram in an embodiment of the present invention.
The configuration of the CRT display device of the present invention will be explained below with reference to FIG.

In the figure, 1 is an AC power supply, 2 is a low voltage output power supply, and 3 is a high voltage output power supply, and each DC output voltage is supplied to each circuit as shown in the figure.

4 is an external signal source, and each signal is supplied to each circuit as shown in the figure. 5 is a horizontal oscillation circuit whose output is supplied to the horizontal output circuit 6 and low voltage output type #i2. 7 is a vertical oscillation circuit, 8
9 is a vertical output circuit, 9 is a video processing circuit, and 10 is a video output circuit. Each output of the horizontal output circuit 6 and the vertical output circuit 8 is supplied to the deflection yoke 11, and each output of the horizontal output circuit 6 and the video output circuit 10 is supplied to the CRT 12.

FIG. 2 shows an embodiment of the low voltage output power source 2 and the high voltage output power source 3 used in the present invention.

The power source used in the present invention will be explained below based on FIG.

In the figure, 2 is a low voltage output power supply, and 3 is a high voltage output power supply. 21.31 is Bringe rectification that rectifies AC input:
'L 22.32 is a capacitor that smoothes the rectified voltage, 2
3.33 is an output transistor that acts as a switch, 24
．． 34 is an output transformer that generates and transforms alternating current by the switching action of the transistor 23.33, 2535 is a rectifier that rectifies the output of the output transformer 24.34, 26, 36
is a capacitor that smoothes the rectified voltage. 27 is an externally triggerable oscillator, 28 is a transformer that supplies pulse voltage to the oscillator 27, and 29 is a transformer.

In the above configuration, when AC voltage is applied, 2
527 oscillates and supplies an alternating voltage to the output transistor 23. Since the output transistor 23 repeats conduction and disconnection according to the input, a pulse current corresponding to the inductance of the output transformer 24 flows. This current is amplified by the action of the output 1 lance 24 and supplied to each circuit that operates at low voltage. As a result, when the horizontal oscillation circuit 5 operates,
Its output is supplied to transistor 29, and the output of transistor 29 is applied by transformer 28 to the trigger input of oscillator 27, so that the output of oscillator 27 is synchronized with the horizontal oscillation output. In this way, the output pulses of the low voltage output power supply 2 are synchronized with the horizontal oscillation output.

The output transistor 33 of the high voltage output power supply 3 has a transistor 33 provided in the output transistor 24 of the low voltage output power supply 2.
The output voltage is supplied from the next winding. During the period when the power is positive, the transistor 33 is conductive, and during the period when the power is negative, it is cut off. Therefore, an output is generated in the high voltage output power supply 3 similarly to the low voltage output type a2.

When the output transistor 23 becomes conductive, its collector voltage becomes O, and the voltage of the tertiary winding of the output transformer 24 becomes positive, so that the output transistor 33 becomes conductive.

When the output transistor 23 is cut off, its collector voltage becomes positive, and the voltage of the tertiary winding of the output transformer 24 becomes negative, so that the output transistor 33 is cut off.

In this way, the two output transistors 23, 33 are simultaneously turned on or turned off, so that they both generate outputs that are synchronized with the horizontal oscillation output.

Effects of the Invention According to the CRT display device of the present invention, both the low-voltage output power source and the high-voltage output power source can be operated in synchronization with the horizontal oscillation circuit with a simple configuration, resulting in stable images without disturbances caused by noise. can be displayed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a CRT display device according to an embodiment of the present invention, and FIG. 2 is a specific circuit diagram of an embodiment of a power supply used in the present invention. 2...Low voltage output power supply, 3...High voltage output power supply, 5...Horizontal oscillation circuit, 23.33.
...Output L transistor, 24.34...
・Output Lance.

Claims (1)

[Claims] A CRT display device having a first switching power supply circuit triggered by an output of a horizontal oscillation circuit and a second switching power supply circuit triggered by an output pulse of the first switching power supply circuit.