KR980009339U - Display monitor device - Google Patents

Abstract

The display monitor device of the present invention is a voltage supply control circuit 58 for controlling a current flowing through the primary winding by receiving a voltage induced in the secondary winding of the transformer 54 when a frequency exceeding an allowable range is input. ) To prevent the image adjustment circuit 40 from being damaged. As a result, the monitor device may be prevented from being damaged due to the use of a host and a display monitor device which are not compatible with each other.

Description

Display monitor device

1 shows the appearance of a typical display monitor device.

2 is a block diagram showing a circuit configuration of the monitor device shown in FIG.

3 is a circuit diagram showing a power circuit around the monitor device according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

40: video adjustment circuit 50: power supply circuit 52: full-wave rectifier

54: smoothing part 56: multiple secondary winding transformer

58: voltage supply control unit 58a: switching unit

58b: pulse width modulation control IC 58c: feedback control unit

58d: IC voltage supply unit 60: protection circuit

[Purpose of designation]

The technical field to which the design belongs and the prior art in the field

The present invention relates to a monitor device which is mainly connected to a host such as a main unit, a game device, an image device, etc. of a personal computer system to display image information.

Conventional monitor apparatuses have only a simple image display function, but current display monitor apparatuses have various functions. As multi-media functions have been added to personal computer systems, various functions have been added to display monitor devices. FIG. 1 shows the appearance of a typical cathode ray tube (CRT) display monitor device, and FIG. 2 shows the circuit configuration of the CRT display monitor device. The monitor device 10 shown in FIG. 1 is a speaker integrated device in which the speakers 12a and 12b are incorporated. In the figure, reference numeral 14 denotes a front control panel for controlling various functions, and numeral 16 denotes a CRT. Although not shown in the drawing, input / output terminals for external microphone input / output, sound input, head-phone, and the like are provided at one side or the rear of the monitor device 10. The front control panel 14 has various adjustment functions such as contrast, brightness, image vertical / horizontal size, horizontal / vertical position, A number of keypads (or buttons) are provided for controlling such as vertical linearity.

Referring to FIG. 2, the monitor device 10 includes a CRT 16, a video signal processing circuit 20, a horizontal / vertical synchronization signal processing circuit 22, a main control circuit 24, and an on screen display (OSD). The control circuit 30, the video mixer circuit 32, the video adjustment circuit 40, and the power supply circuit 50 are provided. Currently, most monitor devices 10 have an OSD function, which refers to displaying menus or adjustment functions in a generally small independent window on the screen of the CRT 16. In the monitor device having the above configuration, the main control circuit 24 receives the monitor driving information from the host, and the control signals necessary for processing the R (red), G (green), and B (bule) signals, and horizontal / Control signals required for the processing of the vertical synchronization signals Hsync and Vsync and a diaplay power management signaling (DPMS) control signal for performing a power saving function of the monitor device are output. The monitor control circuit 24 typically consists of a microcomputer or microprocessor. The video signal processing circuit 20 amplifies the R, G, and B video signals input from the host by the control signal output from the main control circuit 24, respectively. The video signals amplified by this circuit 20 are provided via the video mixer circuit 32 to the R, G and B electron guns of the CRT 16 respectively. The horizontal / vertical sync signal processing circuit 22 converts the horizontal / vertical sync signals Hsync and Vsync input from the host to have a predetermined polarity by using a control signal input from the main control circuit 24 and uses them. Control the horizontal and vertical deflection of the electron beam irradiated from the electron guns. The main control circuit 24 provides the OSD output data to the OSD control circuit 30 in response to the input of the adjustment keys provided in the front control panel 14, whereby the OSD control circuit 30 supplies the R, The G and B video signals are output to the video mixer circuit 32. The video mixer circuit 32 mixes the outputs of the video signal processing circuit 20 and the outputs of the OSD control circuit 30 to the CRT 16. The image adjustment circuit 40 adjusts contrast, brightness, vertical / horizontal size, horizontal / vertical, according to the information output by the main control circuit 24 in response to the user pressing the buttons of the front control panel 14. Position, vertical linearity, horizontal / vertical focus, degauss, video cutoff, video gain, tilt, parallelogram, trapezoidal distortion ( trapezoid). Although not shown in the drawing, most monitor devices have audio amplifying circuits that receive and amplify sound signals from a host and output them to the speakers 12a and 12b.

The power supply circuit 50 of most modern monitor devices operates in the DPMS method established by the Video Electronics Standard Association (VESA). As is well known, the DPMS scheme is divided into a normal mode, a standby mode, a suspend mode, and a power-off mode. When no video signals are input from the host, the power supply circuit 50 enters the standby mode, and when the vertical synchronization signal Vsync is not input, the power supply circuit 50 enters the pause mode, and the horizontal synchronization signal Hsync and the vertical synchronization signal Vsync. The power down mode is entered when none is input. In addition, power consumption is defined for each mode. For example, in the case of a 17-inch monitor, power consumption in the normal mode is defined as about 90 W, and power consumption in the power-off mode is defined as about 8 W. Although not shown, the power supply circuit 50 is, as is well known, a fullwave rectifier section for converting alternating current (AC) to direct current (DC), and pulse width modulation (PWM) control. A secondary, multiple secondary windings transformer, a voltage output that rectifies the voltages respectively derived from the secondary windings or coils of the transformer and outputs a plurality of regulated voltages. A feedback control section for controlling the feedback of the pulse width modulation section, and a DPMS control section for controlling power saving according to a predetermined DPMS control signal provided from the main control circuit 24. It is composed.

On the other hand, in a monitor having various signal timing modes, the size, position, geometric distortion, etc. of a display image or display pattern displayed on a screen may be horizontally input from a host. It depends on the timing of the sync, vertical sync and video signals. The timing of the input signals is determined by the video card mounted on the host and its display mode. In order to obtain an appropriate screen pattern according to the timing change of the input signals as described above, a manufacturer generally selects a timing mode of the corresponding monitor product, that is, a frequency band of the input signal, and displays screen control information related to the frequency band. (Ie screen size, position, and geometric distortion information for each mode) are stored in the monitor (typically, the microprocessor or microcomputer's internal memory) in a predetermined order between the maximum and minimum frequencies of the selected frequency band. This is referred to as 'factory preset mode settings', and the memory area in which screen control information is stored is called a 'factory mode area'. The manufacturing company adjusts and ships a monitor to the screen pattern used as a standard according to its model.

[Technical Challenges to be Done]

While the monitor is operating, the main control circuit 24 detects the frequency of the current input signal using the horizontal and vertical synchronizing signals, and finds the screen control information corresponding to the detected frequency. At this time, if screen control information related to the frequency is stored, the main control circuit 24, that is, the microcomputer, controls the image adjustment circuit 40 according to the information, thereby contrast, brightness, vertical / horizontal size, and horizontal. Adjust vertical position, vertical linearity, horizontal / vertical focus, degauss, video cut off, video gain, tilt, parallelism, trapezoidal distortion, etc. to ensure proper display.

However, when a frequency outside the permitted range (mainly a frequency far exceeding the maximum allowed frequency) is input from the host to the monitor device, the main control circuit 24 cannot find information corresponding to the input frequency and thus stored information. Any of these information is output to the image adjustment circuit 40. Thus, in this case, as the oscillation voltage is rapidly increased above the allowable value, components of the image adjusting circuit 40 which perform the adjustment of the various functions described above, for example, a deflection circuit component and the like are damaged.

The present invention has been made to solve such a conventional problem, and to provide a display monitor device that can prevent circuit components from being damaged when a frequency exceeding an allowable range is input.

[Configuration and Action of Design]

According to a feature of the present invention for achieving the above object, a display monitor device comprises: a primary winding to which a rectified voltage is applied and a plurality of voltages for outputting a plurality of voltages induced by mutual induction with the primary winding; A transformer having secondary windings; An image adjusting circuit operated by the induced voltages to adjust various functions; Voltage supply control means for receiving any one of the induced voltages of the transformer and controlling a current flowing through the primary winding to control the induced voltages; Frequency detecting means for detecting whether the frequencies of the horizontal and vertical synchronizing signals input from the host are allowed ones, and outputting a predetermined control signal when the frequencies are not the allowed ones; And protection means for stopping the operation of the voltage supply control means in response to the control signal to prevent damage to the image adjustment circuit.

In this monitor device, the voltage supply control means includes a transistor having a current path connected between a control terminal and the primary winding of the transformer and ground, and through the current path connected to the control terminal of the transistor. A pulse width modulation control integrated circuit for controlling the flowing current; The protection means supplies a ground voltage to a power supply terminal of the pulse width modulation control integrated circuit in response to the control signal.

In this monitor apparatus, the said protection means is provided with the switch means connected between the said power supply terminal of the said pulse width modulation control integrated circuit, and the said ground voltage, and turned on / off in response to the said control signal.

Next, an embodiment of the present invention will be described in detail with reference to FIG. 3.

EXAMPLE

3 shows a periphery of a power circuit of a display monitor device according to an embodiment of the present invention. Referring to FIG. 3, the novel display monitor apparatus according to the present embodiment receives a voltage induced in the secondary winding of the transformer 56 through a primary winding when a frequency exceeding an allowable range is input. A protection circuit 60 is provided to stop the operation of the voltage supply control circuit 58 that controls the flowing current to prevent the image adjustment circuit 40 from being damaged.

Referring back to FIG. 3, the power supply circuit 50 according to the present embodiment includes a full wave rectifying unit 52 for converting an AC voltage into a DC voltage, and a smoothing unit for smoothing the output of the rectifying unit 52. 54, a multiple secondary winding transformer 56, and a voltage supply control unit 58 for controlling voltages induced in the secondary windings of the transformer. The full wave rectifying unit 52 is formed of a bridge diode circuit, and the smoothing unit 54 is formed of a capacitor C1. The voltage supply control unit 58 is composed of a switching unit 58a, a pulse width modulation (PWM) control IC 58b, a feedback control unit 58c, and an IC voltage supply unit 58d. On the other hand, as is well known, the image adjustment circuit 40 is connected to the secondary windings of the transformer 56. As previously described, this image adjustment circuit 40 is controlled by the main control circuit 24 to provide contrast, brightness, vertical / horizontal size, horizontal / vertical position, vertical linearity, horizontal / vertical focus, degauss, and video cut. Adjust off, video gain, tilt, parallelism, trapezoidal distortion, etc to ensure proper display.

The main control circuit 24, which is composed of a microcomputer or a microprocessor, detects whether the frequencies of the horizontal and vertical synchronization signals Hsync and Vsync input from the host are allowed frequencies, and the input frequencies are not allowed frequencies. Outputs a predetermined control signal FC. The protection circuit 60 is connected to the main control circuit 24. This protection circuit 60 stops the operation of the voltage supply control circuit 58 when the control signal FC is generated from the main control circuit 24, thereby preventing the image adjustment circuit 40 from being damaged. In this embodiment, the protection circuit 60 has a control terminal (i.e., a base terminal) connected to the control signal FC, and a current path (i.e. emitter-collector terminals) is the power supply of the PWM control IC 58b. It is composed of a pnp-type bipolar transistor TR2 connected between the terminal B + and the ground voltage and serving as a switch that is turned on / off in response to the control signal FC. Of course, it will be appreciated that the protection circuit 60 may be composed of npn type transistors, field effect transistors, or other switching elements. In this embodiment, the main control circuit 24 outputs a high level control signal FC when the frequencies of the horizontal and vertical synchronization signals Hsync, Vsync input from the host are allowed. In the opposite case, a low level signal FC is output. Therefore, when the frequencies of the horizontal and vertical synchronization signals Hsync and Vsync are not those allowed, the control signal FC goes low, whereby the transistor TR2 is turned on to cut off the power supply to the voltage supply control circuit 58. do. As a result, the power supply to the image adjustment circuit 40 is also cut off, thereby preventing the image adjustment circuit 40 from being damaged by the application of an unacceptable frequency.

[Effect of design]

According to the present invention, it is possible to prevent the monitor device from being damaged by connecting and using an incompatible host and the monitor device.

Claims (4)

A transformer having a primary winding to which a rectified voltage is applied and a plurality of primary windings for outputting a plurality of voltages induced by mutual induction with the primary winding; A display monitor device having an image adjustment circuit operated by the induced voltages to adjust various functions, the display monitor device comprising: controlling any current flowing through the primary winding by receiving any one of the induced voltages of the transformer; Voltage supply control means for causing the induced voltages to be controlled; Frequency detecting means for detecting whether the frequencies of the horizontal and vertical synchronizing signals input from the host are allowed ones, and outputting a predetermined control signal when the frequencies are not the allowed ones; And a protection means for stopping the operation of the voltage supply control means in response to the control signal to prevent the image adjustment circuit from being damaged. 2. The apparatus of claim 1, wherein the voltage supply control means comprises a transistor having a current path connected between a control terminal and the primary winding of the transformer and ground, and through the current path connected to the control terminal of the transistor. A pulse width modulation control integrated circuit for controlling the flowing current; And said protection means supplies a ground voltage to a power supply terminal of said pulse width modulation control integrated circuit in response to said control signal. The said protection means is provided with the switch means connected between the said power supply terminal of the said pulse width modulation control integrated circuit, and the said ground voltage, and turned on / off in response to the said control signal. Display monitor device. 4. The switch means according to claim 3, characterized in that the switch means comprises a transistor having a current path connected between the control terminal to which the control signal is applied and the power supply terminal of the pulse width modulation integrated circuit and the ground voltage. Display monitor device. ※ Note: This is to be disclosed based on the first application.