KR19990015875U - Monitor's video circuit - Google Patents

Abstract

The present invention relates to an image system of a monitor in which an on-screen display integrated circuit is omitted.

In the conventional video circuit, data transfer is performed by the I ² C protocol between the microcomputer and the on-screen display integrated circuit, and the OSD IC transmits the OSD video signal to the video preamplifier and RGB bias for controlling the bias IC. Since the signal is output, the assembly process and the unit cost increase.

Accordingly, the present invention is a microcomputer capable of outputting an OSD video signal, and receives the OSD video signal and the data transmission with the microcomputer through the I ² C protocol and the RGB bias signal for controlling the bias IC Configure the monitor's video circuit using a video preamplifier that can output.

As described above, the circuit of the present invention can implement the same function as a small number of components, thereby simplifying the assembly process and reducing the price of the product.

Description

Video system of a monitor

The present invention relates to a video circuit of a monitor for displaying a video signal input from the computer main body on a CRT screen.

In general, the monitor is divided into a video system for processing a video signal, a deflection system for vertical and horizontal deflection, and a power system for supplying power required for each circuit, which requires careful attention in relation to image quality. The part is the video lineage.

1 is a block diagram showing a conventional video circuit in a monitor, which is a video preamplifier 11, a video power amplifier 12, a microcomputer 13, a key input unit 14, an on-screen display integrated circuit 15 ) And the bias integrated circuit 16 and the like.

Referring to FIG. 1, when the user presses a menu key of the key input unit 14, the microcomputer 13 recognizes this and controls the on-screen display integrated circuit 15 to display menus related to parameter adjustment on the CRT screen. If the user selects the parameter to be adjusted by using the selection key, the current setting status of the parameter is indicated by the bar, and the user can change the data value of the parameter that is set by using the up-down key.

For example, if the user views the menu, selects the contrast adjustment, and sets the appropriate data with the up-down key, the microcomputer 13 transmits to the on-screen display integrated circuit 15 via the I ² C bus and the OSD IC 15 An OSD image signal (OSD RGB) is output to the video preamplifier 11, and the video preamplifier 11 mixes and amplifies the OSD image signal and the main image signal input through the de-sub connector.

Meanwhile, when the image bias is adjusted in the OSD menu, the microcomputer 13 transmits it to the OSD IC 15 through the I ² C bus, and the OSD IC 15 transmits an RGB bias signal to the bias IC 16. Output so that the adjusted bias value is passed to the CRT.

Here, I ² C, which transmits data between the microcomputer and the OSD IC, is an industry standard bus proposed by Philips, and includes an SDA signal line, an SCL clock line, and a reset signal line for resetting an integrated circuit.

Typically, on an I ² C bus, the SDA bus and SCL bus are pulled up in a "high" state and the data on the SDA bus is supposed to change only while the SCL bus is in a "low" period, where the SCL bus is in a "high" period. Transitioning data from the SDA bus from "high" to "low" indicates a "START" of the data transfer cycle, and a transition from "low" to "high" means the "STOP" of the data transfer cycle. ".

In addition, data or addresses are transmitted in units of 8-bit words on the I ² C bus. A receiver receiving an 8-bit word drops the SDA bus to "low" at the ninth clock of the SCL bus to "ACKNOWLEDGE". Is displayed.

Based on this basic protocol, the write operation and the read operation are performed. In general, the device address, word address, and data are sequentially transmitted in 8-bit units following "START", and finally, the end of transmission is notified by "STOP". At this time, the LSB "0" bit of the device address indicates a read / write operation. If "high", it indicates a read operation from the corresponding device. If it is "low", it indicates a "write" operation to the corresponding device. Each time a data or address is received, an "ACK" signal is transmitted.

However, since the image circuit is a circuit using an integrated circuit having a low density and a single function, the assembly process is complicated due to the large number of parts, and the possibility of failure increases, which causes the monitor quality to deteriorate.

Accordingly, an object of the present invention is to provide a video circuit of a monitor using a high-density, multi-functional integrated circuit.

In order to achieve the above object, a circuit of the present invention includes: a microcomputer that outputs an OSD image signal according to a user input signal input through a key input unit, and is provided with an I2C bus signal line;

A video preamplifier which receives the OSD video signal and the main video signal of the sub-connector, mixes and amplifies them, and outputs a bias control signal to a bias integrated circuit;

A video power amplifier for amplifying a predetermined level or more of an OSD video signal and a main video signal output from the video preamplifier; And

And the bias integrated circuit configured to receive the bias control signal and adjust the light emission balance of the image signal accordingly.

1 is a block diagram showing a conventional video circuit in a monitor;

2 is a block diagram illustrating an image circuit according to the present invention in a monitor.

* Explanation of symbols for main parts of the drawings

21: key input unit 22: micom

23: Video Preamplifier 24: Video Power Amplifier

25: bias IC

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 shows an image circuit according to the present invention in a monitor, which includes a key input unit 21, a microcomputer 22, a video preamplifier 23, a video power amplifier 24, and a bias integrated circuit 25. And the like.

The microcomputer 22 functions as a conventional OSD IC for outputting an OSD image signal according to a user input signal input through the key input unit 21, and transmits data with the video preamplifier 23 of the present invention. I ² C bus signal line is provided.

The video preamplifier 23 is configured to receive and mix and amplify the OSD video signal and the main video signal of the sub-connector, and to output a bias control signal to the bias integrated circuit 25. As the video preamplifier 23, Philips 'TDA4885' is used.

The operation and effects of the present invention configured as described above are as follows.

When the user operates the menu key of the key input unit 21, the microcomputer 22 outputs the OSD image signal to the video preamplifier 23 and outputs a control signal through the I ² C bus.

At this time, the 'TDA4885' used as the video preamplifier 23 has an OSD input terminal for inputting an OSD image signal and an I ² C bus signal line. The main image inputted from the OSD image signal and the sub-connector is provided. The signals are mixed and amplified to a predetermined level and then output to the video power amplifier 24.

That is, since the OSD video signal and the main video signal are low signals of about 1V or less, the video preamplifier 23 amplifies the AC gain of about 4 to 10, respectively, and then the cathode of the CRT in the video power amplifier 24 Amplify the signal from approximately 30V to 50V to drive.

The video signal output from the video power amplifier 24 is loaded on the DC bias voltage output from the bias IC 25 to drive the cathode of the CRT. An OSD menu is displayed on the screen together with the main video signal.

Here, the bias IC 25 is a circuit for reproducing a faithful color image by adjusting the light emission balance of red, green, blue (R, G, B). B There are three electron guns, each of which has different characteristics, even if there is some imbalance in its structure. In addition, since each of the light emitting elements of the R, G, and B light emitting tubes has different light emission rates, different electrode voltages are applied to adjust the R, G, B three-color light emission to be balanced when the screen is bright or dark.

If the user adjusts the image bias in the OSD menu, the microcomputer 22 transmits it to the video preamplifier 23 through the I ² C bus, and the video preamplifier 23 controls the bias IC 25. Causes the bias voltage to be adjusted, which is supplied to the cathode of the CRT.

As described above, the circuit of the present invention can implement the same function as a small number of components, thereby simplifying the assembly process and reducing the price of the product.

Claims (1)

A microcomputer that outputs an OSD video signal according to a user input signal input through a key input unit and is provided with an I2C bus signal line; A video preamplifier which receives the OSD video signal and the main video signal of the sub-connector, mixes and amplifies them, and outputs a bias control signal to a bias integrated circuit; A video power amplifier for amplifying the OSD video signal output from the video preamplifier and a predetermined level or more; And And the bias integrated circuit configured to receive the bias control signal and adjust the light emission balance of the video signal accordingly.