KR930000997Y1 - Input signal selecting circuit of display - Google Patents

Abstract

No content.

Description

Input signal selection circuit of the monitor

1 is a block diagram of an input signal selection circuit of a conventional monitor.

2 is a block diagram of an input signal selection circuit of a monitor according to the present invention.

* Explanation of symbols for main parts of the drawings

1: switching unit 10: interface circuit

2 signal processing unit 3 control unit

4 interface 5 color processing unit

SW1: first switch SW2: second switch

Q1: transistor

The present invention relates to a monitor of a computer, and more particularly, to an input signal selection circuit of a monitor which prevents interference between TTL logic signals and analog signals by switching means so that the monitor can maintain a clear picture quality.

With the development of the technology related to personal computers, various devices for improving the image quality of monitors have been developed, and these devices are mounted in the form of a card in the main body of the computer.

The type of computer card is VGA, CGA, EGA, etc. At this time, the signal output from the card is output with the VGA in an anaload state, and the CGA, EGA card, etc. are output as a TTL digital logic signal. Therefore, the conventional monitor is configured to accommodate changes in signals as these various types of cards are exchanged and mounted in the main body of the computer.

That is, the conventional monitor is configured to be able to input both the analog signal and the TTL logic signal to display on the CRT. FIG. 1 is a block diagram of the input signal selection circuit of the conventional monitor. In order to explain the operation thereof, the analog signal AN or the TTL logic signal TTL input through the terminals A and B is controlled by the first switch SW1 that is switched according to the driving of the user. ) Or to interface 4.

That is, in the case of the analog signal (AN), the signal is directly applied to the signal processing unit (2), and converted into a signal that can be displayed on the cathode ray tube by being processed. The signal processing unit (2) is used for the TTL logic signal (TTL). In order to process the signal, the signal must be input as an analog signal, and then converted into an analog signal at the interface 4 and then applied to the signal processing unit 2.

At this time, the interface 4 is connected to the color processing unit 5 consisting of various switches for controlling the operation of the interface 4, the user is controlling the color processing unit 5, the TTL logic signal is displayed on the cathode ray tube Color, color, etc. can be controlled.

However, in the conventional monitor input signal selection circuit, a constant voltage VCC is always applied to the interface 4 even when the signal input through the first switch SW1 is an analog signal. In the case of operating (5), the interface 4 may malfunction, and a false signal may be applied to the signal processing unit 2 so that the cathode ray tube may generate noise when displaying an analog signal. There is a problem that can cause a failure of the interface.

The present invention is to solve this problem, and the object of the present invention is to configure the controller to cut off the power applied to the interface when the switch inputs an analog signal to remove noise generated on the cathode ray tube while The present invention provides an input signal selection circuit of a monitor that can prevent a malfunction.

A feature of the present invention for achieving this object is a first switch for selectively applying an analog signal or a TTL logic signal to a rear end, and a TTL logic signal connected to the first switch and applied from the first switch. An interface circuit for converting into a log signal, a signal processor connected to the interface circuit and a first switch to drive a cathode ray tube according to a signal applied from the interface circuit and the first switch, and a current connected to the signal processor and the interface circuit. 11. A monitor input signal selection circuit comprising a power supply for supplying a power supply, comprising: a switching unit comprising: a second switch which is turned on when the first switch inputs a TTL logic signal; Switching of the second switch connected between the interface circuit and the power supply made of the switching unit According to the present invention, there is provided an input signal selection circuit of a monitor further comprising control means for controlling the power applied to the interface.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 2 is a block diagram of an input signal selection circuit of a monitor according to the present invention, which comprises a switching unit 1, an interface circuit 10, a signal processing unit 2, and a control unit 3.

In more detail, the switching unit 10 selectively applying the input signals to the rear end may include a first switch SW1 and a second switch SW2, and the first switch SW1 may be a terminal ( When connected to B) the second switch is made to be connected to the terminal (C). In addition, the terminal B of the switching unit 10 may control an interface 4 for converting an input logic signal into a digital signal and outputting the output signal of the interface 4. It is connected to the interface circuit 10 consisting of a color processing unit (5). The switching unit 1 terminal A and the interface 4 are connected to a signal processing unit 2 which processes an input signal as a signal which can be displayed on a cathode ray tube. The second switch SW2 of the switching 1 is connected to the switching transistor Q1 so that power is applied to the interface 4 through the transistor Q1 according to the switching of the second switch SW2. Is done.

The input signal selection circuit of the monitor according to the present invention made as described above has the same function as the conventional one. However, the second switch SW2 of the switching unit 1 is switched together with the first switch SW1 to control the driving of the transistor Q1, thereby preventing power from being applied to the interface when an analog signal is input. Done.

That is, when the first switch SW1 is connected to the terminal A so that the input analog signal AN is applied to the signal processor 2, the second switch SW2 is in an open state. Therefore, since the potential at the base side of the transistor Q1 rises and is in the off state, the power supply VCC is not applied to the interface 4, and the interface 4 stops driving.

Therefore, even when the user input signal is mistaken for the TTL logic signal and the color processor 5 is adjusted, the interface 4 does not output any signal, and thus the signal processor 2 is disconnected from the interface 4. The noise is not applied, and the analog signal AN applied from the terminal A is displayed on the cathode ray tube, so that no noise is generated on the cathode ray tube.

When the first switch SW1 is connected to the terminal B to apply the input TTL logic signal TTL to the interface 4, the second switch SW2 is connected to the terminal C. By lowering the base-side potential of the transistor Q1, the transistor Q1 is driven to apply power to the interface 4. Accordingly, the interface 4 converts the input TTL logic signal TTL into an analog signal, and converts the value of the analog signal output according to the adjustment of the color controller 5 to adjust colors and colors. You can adjust it as you want. The analog signal output from the interface 4 is displayed on the cathode ray tube by the signal processor 2.

In this way, the input signal selection circuit of the monitor according to the present invention constitutes a second switch in the switching unit, and configures a control unit for supplying power to the interface according to the driving of the second switch. By stopping the driving, it is possible to prevent the generation of a false signal generated by the interface, so that the monitor can always maintain a clear picture quality.

Claims (2)

A first switch unit SW1 for selecting an analog signal AN or a TTL logic signal TTL, and a TTL logic signal TTL connected to the first switch SW1 and applied from the first switch SW1. ) Is converted into an analog signal and connected to the interface circuit 10 and the first switch SW1 according to a signal applied from the interface circuit 10 and the first switch SW1. A signal processor (2) for driving a cathode ray tube and a power supply (VCC) connected to the signal processor (2) and the interface circuit (10) for supplying current to the signal processor (2) and the interface circuit (10); And a switching unit (1) comprising a second switch (SW1) which is turned on when the first switch (SW1) inputs a TTL logic signal. It is connected between the interface (4) and the power supply (VCC) to the switching unit (1). Control means for controlling the application of the power supply (VCC) to the interface circuit (10) in accordance with the switching of the second switch (SW2) made, characterized in that it further comprises a. The transistor of claim 1, wherein the control unit is connected between the second switch SW2 and the power supply VCC to control the power supply of the interface 4 according to the driving of the second switch SW2. And an input signal selection circuit of the monitor consisting of (Q1) and (Q1).