KR19980015197A - The monitor's automatic power control circuit for use with a monitor - Google Patents

Abstract

The present invention relates to an automatic power control circuit for a monitor for controlling power of a monitor according to whether a PC signal generated from a computer main body is generated to reduce power consumed in a monitor and includes a bridge diode for rectifying an AC output from a commercial AC input terminal, A PWM IC for receiving a direct current output from the bridge diode and modulating a pulse width to output a pulse signal; a switch for receiving a pulse signal output from the PWM IC to output a switching signal; A rectifier for rectifying a current output from the switching transformer and outputting a direct current; a rectifier for receiving a PC signal output from the PC to receive the PWM signal, Control the power of monitor by controlling IC A power control switch for detecting whether a PC signal output from the PC is generated by using a switch and automatically turning on / off the monitor, thereby reducing power consumption.

Description

Monitor's automatic power control circuit (AUTOMATIC POWER CONTROL CIRCUIT FOR USE WITH A MONITER)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic power control circuit for a monitor and, more particularly, to an automatic power control circuit for controlling power of a monitor according to whether a personal computer (PC) To an automatic power control circuit of a monitor.

Generally, a central processing unit (CPU) in a computer main body has various output devices for processing one program or data and outputting processed results. Of the display devices, among the output devices, which are capable of confirming the results directly processed by the PC user, monitors require a large amount of power consumption. These monitors use high voltages to display data output from the computer's main body, which makes the manufacturers producing monitors a great deal of effort to conserve the power consumed by high voltages.

One of such efforts is to reduce the power consumed by the monitor by using Display Power Management Signaling (DPMS) of the display device. The DPMS detects whether horizontal and vertical synchronizing signals output from a video card, which is a video signal generating device in a computer main body, are generated using a microcomputer, and generates a DPMS mode signal according to the sensed result.

The DPMS mode signal output from the microcomputer includes a standby mode in which the video signal output from the monitor is blocked when the horizontal synchronization signal is off, a suspend mode in which the deflection voltage is shut off when the vertical synchronization signal is off, When the synchronizing signal is turned off, a power-off mode is executed to shut off the secondary side power supply of the transformer using the pulse width modulation circuit, thereby saving power consumed by the monitor.

The general DPMS control circuit will be described with reference to the accompanying drawings.

1 is a block diagram showing an internal circuit of a conventional monitor which is generally used. As shown in the figure, the PC 100 includes a CPU 110 for receiving and processing a keyboard signal used by a user and generating data according to a processed result, (H-SYNC) for synchronizing the processed video signals R, G and B with the video signals R, G and B and a vertical synchronizing signal V- And a video card 120 for outputting a video signal SYNC.

The monitor 200 receiving the video signals R, G and B and the horizontal synchronizing signal H-SYNC and the vertical synchronizing signal V-SYNC output from the video card 120 in the PC 100 A microcomputer 210 for receiving a horizontal synchronization signal H-SYNC and a vertical synchronization signal V-SYNC, a control button for generating a screen control signal for controlling the monitor screen and outputting the generated monitor screen control signal A horizontal and vertical output circuit 230 for synchronizing a raster with a monitor screen control signal output from the microcomputer 210 and a reference oscillation signal; A power circuit unit 240 for supplying a driving voltage to the microcomputer 210, the horizontal and vertical output circuit units 230 and the video signal processing unit 240; 250).

Each block in the monitor 200 having such a structure will be described in more detail as follows.

The microcomputer 210 receives the horizontal synchronizing signal H-SYNC and the vertical synchronizing signal V-SYNC output from the video card 120. The microcomputer 210 receiving the horizontal synchronization signal H-SYNC and the vertical synchronization signal V-SYNC incorporates various monitor screen control data. When the monitor screen control signal is applied to the microcomputer 210 by the control button unit 220, the microcomputer 210 outputs an upper adjustment signal for adjusting the image displayed on the monitor screen according to the applied screen control signal .

The control button unit 220 outputs horizontal and vertical position control signals, horizontal and vertical size adjustment signals, and the like. The microcomputer 210 receiving the monitor screen control signal outputs a phase adjustment signal and a reference oscillation signal according to the monitor screen control signal applied thereto. The reference oscillation signal outputted from the microcomputer 210 is applied to the horizontal and vertical oscillation signal processor 230-1 in the horizontal and vertical output circuit unit 230. [ In addition, the horizontal and vertical oscillation signal processor 230-1 receives horizontal and vertical oscillation signals applied from horizontal and vertical oscillation circuits (not shown).

The horizontal and vertical oscillation signal processor 230-1 receiving the horizontal and vertical oscillation signals generates a sawtooth wave based on the horizontal synchronizing signal H-SYNC and the vertical synchronizing signal V-SYNC applied from the video card 110, The switching speed of the on / The vertical pulse output from the horizontal and vertical oscillation signal processor 230-1 is applied to the vertical drive circuit 230-2.

The vertical drive circuit 230-2, which receives the vertical oscillation signal, generally uses one stage of the vertical amplification type. The emitter follower 230-2 applies an input to the base terminal of the transistor and extracts an output voltage from the emitter terminal. The mold is used a lot. Therefore, the linearity improving operation is performed rather than the gain. The vertical output circuit 230-3 receiving the current signal output from the vertical drive circuit 230-2 generates a sawtooth current corresponding to the vertical synchronization pulse flowing through the V-DY 230-4, The vertical scanning period is determined.

In addition, the horizontal drive circuit 230-5 receives the horizontal oscillation signal output from the horizontal and vertical oscillation signal processor 230-1. The horizontal drive circuit 230-5 supplies the horizontal oscillation signal with sufficient current to turn on / off the horizontal output circuit 230-6. The horizontal drive circuit 230-6 is an in-phase (polarity) type in which the output stage is turned on when the drive stage is on, and a reverse phase (reverse polarity) mode in which the output stage is also off when the drive stage is currently in use have. The horizontal output circuit 230-6 receiving the current output from the horizontal drive circuit 230-5 generates a sawtooth current in the H-DY 230-7. The horizontal scanning period is determined by the sawtooth current.

A retrace collector is used through a flyback transformer (FBT) 230-9 to supply a stable DC voltage to the anode of the CRT 240-3 and a leakage inductance A large high voltage is generated even when the collector pulse is small, and the anode voltage of the cathode terminal of the cathode ray tube (hereinafter referred to as CRT) 240-4 is increased by using harmonics due to the distributed capacitance of the high voltage circuit 230-8. (240-4-1).

A process of displaying a video signal on the CRT 240-3 in the video signal processor 240 receiving the high voltage through the anode terminal 240-3-1 will be described below. The OSD unit 240-1 receiving the OSD gain signal generated by the screen control through the microcomputer 210 generates and outputs the OSD gain signal.

The video preamplifier 240-2, which receives the OSD gain signal output from the OSD unit 240-1 and the video signals R, G, and B applied from the video card 120, (R, G, B) are amplified to maintain a constant voltage level. For instance, for example to amplify a signal of less than 1V _PP into a signal of 4 ~ 6V _PP. Thus, the video output amplifier that amplifies a signal of 4 ~ 6V _PP (240-3) will supply the energy in each pixel to amplify a signal of 40 ~ 60V _PP. The video signal amplified by the video output amplifier 240-3 is applied to the cathode of the CRT 240-4 and the video signals R, G, and B are displayed on the monitor screen.

The power supply circuit unit 250 for supplying the driving voltage for displaying the video signals R, G, and B through the monitor screen includes an alternating current (AC) input terminal 250-1 ). The degaussing coil 250-2 receiving the AC output through the AC input terminal 250-1 can recover the color blurring state caused by the color purity of the monitor screen or the external condition to the original color . When an alternating current is applied to the degaussing coil 250-2 instantaneously for 2-8 seconds to perform this operation, the magnetic field formed in the shadow mask in the monitor 200 is disturbed, .

Also, the alternating current outputted through the AC rectifier 250-3 is rectified through the rectifier 250-3 and applied to the switching transformer 250-4. The switching transformer 250-4 receiving the DC applied through the rectifier 250-3 performs switching operation to supply various driving voltages required in the monitor 200 through the voltage output terminal 250-5 . At this time, if the vertical synchronization signal H-SYNC is not applied from the video card 120, the microcomputer 210 applies the suspend mode signal to the voltage regulator 250-6 to cut off the deflection voltage.

At this time, the pulse width modulation (PWM) unit 250-7 allows the on / off drive operation of the switching device, and the pulse width changes the conduction time by increasing or decreasing the conduction time Thereby stabilizing the voltage. If the PWM unit 250-7 does not detect the horizontal synchronization signal H-SYNC and the vertical synchronization signal V-SYNC in the microcomputer 210, the microcomputer 210 outputs a power off mode signal . The PWM unit 250-7, which has received the power off mode signal, enters the low level state to shut off the voltage supplied to the monitor 200. [ Thus, the power consumed in the monitor 200 is saved.

The DPMS control circuit will now be described in more detail with reference to the accompanying drawings.

2 is a block diagram showing a conventional power supply control circuit, which processes an image signal for displaying data processed in a PC 100 (shown in FIG. 1) and outputs the image signals R, G, A video card 120 for outputting a signal H-SYNC and a vertical synchronization signal V-SYNC and an AC input terminal 250-1 constituting a monitor 200, A line filter 250-7 for eliminating noise input into the commercial AC output from the commercial AC input terminal 250-1 and rectifying the AC output from the line filter 250-7, A switching transformer 250-4 for applying a current rectified and output from the rectifying circuit 250-3 and backing up the current, a horizontal synchronizing signal H -SYNC) and the vertical synchronization signal (V-SYNC) are detected, and according to the detected result, A microcomputer 210 for outputting a standby mode signal output from the microcomputer 210 and an output terminal for outputting an English mute signal according to an applied standby mode signal, A luminance controller 260-2 for receiving a video mute signal output from the video mute circuit 260-1 to adjust a brightness of a video signal, a video mute circuit 260-1 for outputting the video mute signal, A contrast controller 260-2 which receives the image mute signal output from the microcomputer 260-2 and adjusts the contrast of the image signal according to the applied image mute signal, A voltage regulator 250-6 for receiving a control signal and for interrupting a driving voltage of the deflection circuit in accordance with an applied suspend mode signal, A PWM unit 250-7 that receives a power off mode signal and blocks the output of the switching transformer 250-4 according to an applied power off signal, A video preamplifier 240-2 for receiving a contrast control signal output from the contrast controller 200-9 and amplifying the contrast control signal to a predetermined level, A video main amplifier 240-3 for finally amplifying the signals R, G and B and a video signal R, G and B finally amplified and outputted in the video main amplifier 240-3, And a CRT 240-4 that receives a luminance gain control signal output from the luminance controller 260-2 and incorporates a first grid G1 for adjusting the brightness of the video signals R, G, and B .

The operation of the conventional power supply control circuit configured as described above will be described below.

The commercial AC inputted through the AC input terminal 250-1 is removed through the line filter 250-7 and the noise flowing along with the use AC. The commercial AC having no noise through the line filter 250-7 is applied to the switching transformer 250-4 through the DC voltage rectified through the rectifying circuit 250-4. The switching transformer 250-4, to which the DC voltage is applied, is controlled by the PWM 250-11 to output a current. In addition, the degaussing circuit receiving the AC output from the line filter 250-7 makes it possible to eliminate the color blurring phenomenon occurring on the screen of the monitor.

Meanwhile, the microcomputer 210 in the monitor 200 detects a horizontal synchronizing signal (H-SYNC) and a vertical synchronizing signal (V-SYNC) generated in the video card 120 in the computer main body. If the microcomputer 210 detecting the horizontal synchronizing signal H-SYNC and the vertical synchronizing signal V-SYNC does not detect the horizontal synchronizing signal H-SYNC, the standby mode signal is supplied to the video mute circuit 260-1, . The video mute circuit 260-1 receiving the standby mode signal controls the brightness controller 260-2 to adjust the first lead G1 in the CRT 240-4 to block the brightness of the displayed image do.

Also, the contrast controller 260-2, which receives the video mute signal output from the video mute circuit 260-1, controls the video preamplifier 240-2. The video preamplifier 240-2 under the control of the controller 260-2 amplifies and outputs the contrast control signal, that is, the brightness control signal of the video signal, at a constant level, A standby mode is performed in a DPMS mode signal for reducing the power consumed in the monitor 200 by shutting off the video signals R, G, and B displayed on the CRT 240-4 by adjusting the video signals.

If the vertical synchronization signal V-SYNC output from the video card 120 is not generated, the microcomputer 210 senses the vertical synchronization signal and outputs a suspend mode signal. The voltage regulator 250-6, which receives the suspend mode signal output from the microcomputer 210, cuts off the power supplied to the deflection circuit (not shown) to shut off the high voltage circuit part in the monitor 200, Span mode will be executed.

If the horizontal synchronizing signal H-SYNC and the vertical synchronizing signal V-SYNC are not outputted from the video card 120, the microcomputer 210 detects the signal and outputs a power-off mode signal. The power off mode signal output from the microcomputer 210 is applied to the PWM 250-3. The PWM 250-3 having received the power-off mode signal controls the switching transformer 250-4 to perform a power-off mode during the DPMS mode in which the monitor is turned off by shutting down the power consumed in the monitor.

This conventional DPMS control circuit saves power consumed by the monitor depending on whether a horizontal synchronizing signal (H-SYNC) and a vertical synchronizing signal (V-SYNC) output from the video card 120 are generated.

In the conventional power saving mode, a control program is separately used for a microcomputer, so that a capacity for realizing another function using a microcomputer must be increased.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a circuit for detecting whether a signal outputted from a computer main body is generated using a simple switching means and for turning on / off the power of an LCD and a monitor do.

1 is a block diagram showing an internal circuit of a conventional monitor which is generally used;

2 is a block diagram showing a conventional power supply control circuit,

3 is a circuit diagram showing automatic power control of a monitor according to the present invention.

FIG. 3 is a circuit diagram showing an automatic power control of a monitor according to the present invention. The automatic AC power supply control circuit includes a commercial AC input terminal 10 to which commercial AC is input, a bridge diode 20 to rectify the AC output from the commercial AC input terminal 10, A PWM IC 30 receiving a direct current output from the bridge diode 20 and modulating the pulse width to output a pulse signal, a control IC 30 receiving a pulse signal output from the PWM IC 30, A switching transformer 50 which receives a switching signal output from the switch 40 and generates a current according to an applied switching signal and outputs the induced current; A rectifier 60 for rectifying the current to output a direct current (DC), a PC 70 for outputting a PC signal, and a controller 70 for receiving the PC signal from the PC 70 and controlling the PWM IC 30, And a power source control switch 80 for controlling the power source of the power source.

In this configuration, the bridge diode 10 includes a plurality of diodes D1 to D4, and the switch 40 is a field effect transistor Q1.

The switching transformer 50 is composed of a plurality of coils L11, L21 and L31 and the power source control switch 80 is a transistor Q2 and a capacitor C.

The operation according to this will be described as follows.

And rectifies the AC signal inputted through the commercial AC input terminal 10 through the bridge diode 20. When a positive AC waveform is applied to the bridge diode 20 in an alternating current waveform, the bridge rectifier 20 rectifying the alternating current is rectified through the diode D1 to output a positive half wave and a diode D3) flows through the auxiliary AC input terminal. When a negative AC waveform is input from the commercial AC input terminal 10, a positive half wave is rectified through the diode D4, and a negative half wave flows through the diode D2 to the commercial AC input terminal.

Thus, the positive half wave rectified and outputted through the bridge diode 40 is smoothed through the capacitor C2. The smoothed direct current through the capacitor C1 is induced through the resistor R for the starting voltage and is applied to the PWM IC 30. [ The PWM IC 30, which receives the induced DC through the resistor R for the starting voltage, controls the pulse width when the overload occurs and outputs the controlled pulse.

The pulse output from the PWM IC 30 is applied to the switch 40, and the switch 40 to which the pulse is applied performs a switching operation. When the switch 40 performs the switching operation, the switching transformer 50 induces a direct current input according to the switching operation. That is, when a high level signal is output from the switching signal outputted from the switch 40, electric charge is accumulated in the coil L1. When a low level signal is outputted from the switching signal outputted from the switch 40 again, A back electromotive force is generated and is induced through the diode L2 via the diode D5 to output a DC voltage.

The DC voltage thus outputted supplies the voltage required for driving the monitor.

At this time, if the user does not use the PC 70, the PC 70 does not generate the PC signal. When a PC signal is not output from the PC 70, a low level signal is applied to the base end of the transistor Q2 in the power source control switch 80. [ When a low level signal is applied to the base stage, the transistor Q2 is turned on. When the transistor Q2 is turned on, the PWM IC 30 enters the low level state. Therefore, the operation of the switching transformer 50 is stopped as the switch 40 is stopped and the switch 40 is stopped due to the low level state of the PWM IC 30. At this time, charges are accumulated in the coil L3 in the switching transformer 50. [

Conversely, when the PC 70 is in the off state and the PC signal is generated, the generated PC signal is supplied to the base terminal of the transistor Q2 in the power supply control switch 80 as a high level signal The transistor Q2 is turned off. At this time, a counter electromotive force is generated in the coil L31 in the switching transformer 50 to supply the driving voltage of the transistor Q2. When the transistor Q2 driven by the counter electromotive force outputted from the coil 31 is turned off, the PWM IC 30 performs a normal operation and supplies power to each circuit through the switching transformer 50 to turn on the monitor .

At this time, the capacitor C2 in the power supply control switch 80 is used for noise removal.

As described above, the present invention has the effect of reducing power consumption by sensing whether a PC signal output from a PC is generated using a switch and automatically turning on / off the monitor.

Claims (2)

A PWM IC for receiving a direct current outputted from the bridge diode and modulating a pulse width to output a pulse signal, and a pulse signal output from the PWM IC A switching transformer that receives a switching signal output from the switch and generates a current according to an applied switching signal and outputs the current; and a rectifier that rectifies a current output from the switching transformer to output a direct current And a power supply control switch for receiving a PC signal output from the PC and controlling the power supply of the monitor by controlling the PWM IC. The automatic power control circuit for a monitor according to claim 1, wherein the power control switch unit is a transistor that receives a PC signal output from a PC and performs a switching operation.