KR19980085723A - Power supply circuit of ultra low power monitor - Google Patents

Abstract

The present invention relates to a power supply circuit for a monitor, comprising: a bridge diode (63) for rectifying an input AC power; an SMPS (1) for receiving a rectified voltage and supplying a necessary voltage to each part of the monitor; And a switching unit 20 for switching the sensing unit 10 so that the rectified voltage is not applied to the SMPS when the sensing unit 10 senses that the monitor is in the off mode and outputs a high level control signal Even if the microcomputer stops driving when the monitor is in the off mode and the microcomputer stops driving, the SMPS is driven again when there is a horizontal synchronizing signal input from the PC, The power consumption can be greatly reduced.

Description

Power supply circuit of ultra low power monitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit of a power saving monitor, and more particularly, to a power supply circuit of an ultra-miniature monitor that minimizes power consumption wasted in a power saving mode.

In recent years, various technologies have been proposed to reduce power consumption when environmental energy issues are becoming internationally recognized. As a result, various efforts have been made to reduce the power consumption of monitors that have become one of the most widely used electric products due to the influence of office automation (OA). As a result of these efforts, VESA has become an international standard And the proposed DPMS standard.

As already well known, in Display Power Management Signaling (DPMS), four power states are defined and identified in response to the state of Advanced Power Management (APM) operating in the computer main body as shown in the following Table 1 Horizontal and vertical synchronization signals are used. Here, APM is a computer power management processor set by Microsoft and IBM.

[Table 1]

condition signal Degree of demand Power saving Normal recovery time Horizontal sync Vertical synchronization video On has exist has exist Normal input compulsion Save money - Standby none has exist Blanking option small short Suspend has exist none Blanking compulsion versus Kim off none none Blanking compulsion maximum -

As shown in Table 1, in DPMS, the status (or mode) is on, stand-by, suspend, off, and the monitor accepts at least on, suspend, shall.

Here, the four states will be briefly described as follows. First, the on-state (mode) is a state in which both the horizontal synchronizing signal and the vertical synchronizing signal input from the computer through the D-sub and the video signal are normally input and displayed on the screen.

The standby state (mode) is a state in which there is no horizontal synchronizing signal input from the computer through the D-sub, but only a vertical synchronizing signal, the video signal is blanked and nothing is displayed on the screen. It is a state where power is saved.

The suspended state (mode) is a state in which there is a horizontal synchronous signal input from the computer through the D-sub, there is no vertical synchronous signal, the video signal is blanked and nothing is displayed on the screen. . Finally, the off state (mode) is a state in which the power is off, there are no vertical and horizontal sync signals, the video signal is blanked, and the power is saved to the maximum.

Meanwhile, each state defined by the DPMS as described above is only schematically defined, and a specific technique for implementing each state can be implemented in various forms by the monitor manufacturer.

As one of such various technologies, there are an output voltage drop method in which the total power consumption is reduced by drastically lowering the primary voltage of the monitor power supply circuit (SMPS) in a power saving mode such as the suspend mode and the off mode, An output voltage open method for reducing unnecessary power consumption in power saving mode to reduce power consumption has been proposed.

1 is a circuit diagram showing a power supply circuit of a power saving type monitor implemented by a general output voltage drop method. Referring to the operation of the power supply unit 60, first, a commercial AC power of 100 V or 220 V is supplied from a power input unit 61, The line filter L1 and the X capacitor C1, the line filter L2 and the Y capacitors C2 and C3 of the input filter unit 62 are connected to each other through the AC power source Remove the incoming noise.

The Y capacitors C2 and C3 and the line filter L2 of the input filter unit 62 are connected in parallel to each other by the high frequency noise generated when the bridge diode D1 63 and the control IC 67 operate, . The AC voltage having passed through the line filter L1 and the Y capacitor C2 is rectified by the bridge diode D1 63 and smoothed by the smoothing capacitor C4 through the resistor R1 for preventing the inrush current to generate a DC voltage And is then applied to the primary coil of the transformer 65. [

At the same time, the rectified voltage rectified by the bridge diode D1 (63) is applied to the control IC 67 Resistance to stage And the power transistor 66 is turned on / off by a control signal output from the control IC 67. The control IC 67 is operated by the control IC 67, That is, the DC voltage ( Is applied to the capacitor C5, a DC voltage ( ) Is charged, the supply voltage of the control IC 67 Reaches the starting voltage, the control IC 16 is activated to generate the PWM control signal, and the power transistor 66 is turned on / off by the PWM control signal.

When the power transistor 66 is turned on and off for a predetermined period of time according to the oscillator period in the control IC 67, an induced electromotive force induced in the secondary winding of the primary winding of the transformer 65 is generated .

Therefore, the transformer 65 is controlled by the PWM control signal so that the AC voltage ( .

By repeating the above operation, the alternating-current voltage (?) Output from the secondary winding of the transformer 65 Is rectified by the DC voltage ( ).

That is, the AC voltage (?) Input to the rectifying circuit Are rectified by rectifying diodes D2 and D3 and smoothing capacitors C6 and C7 , 100 V) and supplied to the horizontal / vertical deflection unit 20, the video amplifier 30, and the heater H of the CRT to operate the circuit.

Meanwhile, the power supply voltage 100V supplied to the video amplifier 30 is also branched and applied to the power saving mode controller 50. Accordingly, the power saving mode controller 50 receives a high level of power saving from the microcomputer 40 The first transistor 11 is turned on and the power supply voltage of 100 V is inputted to the collector terminal of the first transistor Q1 through the Zener diode D4 and flows to the emitter terminal to be grounded.

At this time, since the collector terminal of the first transistor Q1 and the base terminal of the second transistor Q2 are connected in parallel, the current passing through the Zener diode D4 flows only toward the first transistor Q1, The second transistor Q2 does not flow toward the transistor Q2, so that the second transistor Q2 maintains the turn-off state.

Therefore, the voltage (100 V) output from the power supply unit 60 is directly supplied to the horizontal / vertical deflection unit 20, the video amplifier 30 and the heater H to operate the circuits normally.

However, when the low-level power saving signal is input from the microcomputer 40 to the power saving mode control unit 50 in the suspend mode or the off mode, the first transistor Q1 is turned off, The voltage can not flow toward the first transistor Q1 and is applied to the base end of the second transistor Q2.

Accordingly, the second transistor Q2 is turned on and the 100V power supply voltage is input to the collector terminal of the second transistor Q2 through the diode D5 and flows to the emitter terminal to be grounded.

At this time, more current flows in the photocouplers 69-1 and 69-2 located between the output of the power supply unit 60 and the collector of the second transistor Q2 than in the normal mode, and the overcurrent flows through the control IC 67) ).

Thus, the feedback stage of the control IC 67 The on time of the power transistor 66 is shortened and outputted to the transformer 65 so that the transformer 65 outputs a voltage smaller than 100V.

While the low-level power saving signal is input from the microcomputer 40, the process is repeatedly performed until the power saving voltage falls below a predetermined power saving voltage level, that is, 30 V or less, and supplies the power to the horizontal / vertical deflection unit 20 and the audio amplifier 30.

At this time, since the heater H is not easily heated as described above, the rated voltage is applied to the heater H even if the power saving function is performed on the monitor, The supply voltage to be supplied is cut off.

However, the power supply circuit of the power saving monitor realized by the output voltage drop method as described above is complicated in the circuit for obtaining the voltage required at the secondary side of the transformer in the power saving mode, and the power supply unit continuously drives the power supply in the power saving mode The power consumption can not be reduced to a certain level or less.

It has been mentioned that the DPMS of the output voltage open type is used together with the output voltage drop method as described above. The power supply circuit of the power saving monitor to which the output voltage open method is applied can reduce power consumption by turning off an unnecessary output voltage in the power saving mode.

However, this is because it is difficult to control because the switching element of the primary side of the transformer must secure the minimum on-time, and the power supply portion continuously drives even in the suspend mode or the off mode, There is a problem.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to minimize the power consumption by causing the power supply unit to operate in response to the horizontal synchronization signal output from the PC, Power supply circuit of a monitor which is capable of reducing power consumption.

According to an aspect of the present invention, there is provided a monitor power supply circuit for rectifying input AC power from a bridge diode, applying the rectified voltage to the SMPS, and supplying a necessary voltage to each part of the monitor through the SMPS ,

Sensing means for sensing when the monitor enters the off mode,

And a switching unit for switching the sensing unit to prevent the rectified voltage from being applied to the SMPS when the sensing unit senses that the monitor is in the off mode and outputs a high level control signal,

And the SMPS stops driving when the monitor enters the off mode.

1 is a circuit diagram showing a general power-saving type monitor,

2 is a circuit diagram showing a power supply circuit of an ultra-miniature monitor according to the present invention,

3 is a graph showing a horizontal synchronous signal in a steady state,

4 is a graph showing a horizontal synchronization signal in the off mode.

DESCRIPTION OF THE REFERENCE NUMERALS

1: SMPS10: sensing means

11: light emitting portion 12: light receiving portion

20: switching section 21: SCR

TR1, TR2, TR3: transistor D1: Zener diode

C11, C12: Capacitor

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

FIG. 2 shows a power supply circuit of an ultra-miniature monitor according to the present invention. The power supply unit 61 receives a commercial input AC power of 110V or 220V through a fuse, A bridge diode 63 for rectifying and rectifying the input AC power and outputting a rectified voltage, and a rectifier circuit 63 for receiving a rectified voltage outputted from the bridge diode 63, A sensing unit 10 for sensing when the monitor enters the off mode, and a sensing unit 10 for sensing that the monitor is in the off mode and outputting a high level control signal And a switching unit 20 for switching the rectified voltage so as not to be applied to the SMPS 1.

Here, the sensing unit 10 includes a light emitting unit 11 that is turned on when a normal horizontal synchronizing signal H.sync is input from the PC, and a switching unit 12 that is turned on when the light emitting unit 11 emits light, And a high level control signal (OFF) output from the microcomputer when the monitor is in the normal mode or the suspend mode, and is turned on to turn on the light emitting unit A Zener diode D1 for controlling the voltage applied to the light receiving unit 12 to be constant at all times; a first transistor TR1 for causing the first transistor TR1 to emit light, And a first capacitor C11 for blocking the high level DC signal from being applied to the light emitting unit 11 when a horizontal synchronizing signal is inputted.

When a high level control signal is output from the light receiving unit 12 of the sensing means 10, the switching unit 20 applies a high level to the gate terminal G and outputs a rectified voltage An SCR 21 which is applied to the anode stage A and to which the cathode stage K and the SMPS 1 are connected and an SCR 21 which is connected between the cathode stage K of the SCR 21 and the SMPS 1, A second capacitor C12 for storing a peak voltage of the rectified voltage while the first switch 21 is turned on and a second capacitor C12 for turning on the gate of the SCR 21 when the control signal of high level is outputted from the light receiving unit 12, And a second transistor TR2 and a third transistor TR3 for applying a high level to the scan line G. [

The operation and effect of the present invention configured as described above will now be described in detail when the monitor is in the normal mode, when the mute function is performed, when the monitor is in the off mode, and again when the monitor is in the normal mode.

First, the horizontal synchronization signal, the suspend control signal, and the off control signal will be briefly described. There are two waveforms of the horizontal synchronization signal H.sync in the steady state output from the PC to the monitor, There are a pulse waveform that transits from a low level to a high level and a pulse waveform that transitions from a high level to a low level as shown in FIG. 3B.

There are two waveforms of the horizontal synchronizing signal in the off mode output from the PC to the monitor. As shown in FIG. 4A, there are a high level DC waveform and a low level DC waveform as shown in FIG. 4B.

The microcomputer of the monitor outputs a high-level suspend control signal and a high-level off control signal in a normal mode in which a horizontal synchronizing signal and a vertical synchronizing signal are input from the PC, and outputs a low level Level control signal, and outputs a low-level suspend control signal and a low-level off-control signal in an off mode in which neither the horizontal synchronizing signal nor the vertical synchronizing signal is input from the PC.

1, when the monitor is in the normal mode,

The microcomputer outputs a high level off control signal (OFF) when a normal horizontal synchronizing signal H.sync is inputted from the PC, and the first transistor TR1 is turned on by the high level off control signal (OFF) The light emitting unit 11 is turned on and the horizontal synchronizing signal H.sync that is rectified by the resistor R and the first capacitor C11 becomes high level and the light emitting unit 11 is turned on .

The light receiving unit 12 is turned on and the switching unit 20 outputs a high level control signal to the second transistor TR2 and the third transistor TR3, Are turned on and a high level is applied to the gate terminal G of the SCR 21 to turn on the SCR 21.

That is, when the anode terminal A and the cathode terminal K of the SCR 21 are short-circuited and a rectified voltage rectified by the bridge diode 63 is applied to the SMPS 1 and the SMPS 1 is driven in a steady state And the peak voltage of the rectified voltage is accumulated in the second capacitor C12.

2, When performing the mute function,

The mute function in the monitor means that if the voltage (rated voltage) necessary for each monitor circuit is supplied at a time when the monitor is powered on / off or in a mode change, the monitor circuit will cause an abnormality, Or to supply the rated voltage after supplying the preparatory voltage lower than the rated voltage so that each monitor circuit warms up at the initial stage of mode conversion and can perform normal operation.

In particular, if the monitor mode is changed while the monitor is operating in the normal mode, the PC temporarily does not output the horizontal synchronization signal H.sync. Even if the horizontal synchronization signal H.sync is not input The first transistor TR1 is turned on by the high level off control signal OFF so that the light emitting portion 11 and the light receiving portion 12 are electrically connected to the gate terminal G of the SCR 21, The rectified voltage of the bridge diode 63 is applied to the SMPS 1 so that the SMPS 1 can be driven in a steady state.

3, in the off mode,

If the PC user does not strike the keyboard for a long time, the PC outputs a high level DC signal or a low level DC signal as a horizontal synchronization signal (H.sync) so that the monitor is switched to the off mode. Mode, the microcomputer outputs an OFF control signal (OFF) of a low level.

That is, the first transistor TR1 is turned off by the OFF control signal (OFF) of the low level, and the low level direct current signal and the high level direct current signal, which are input with the horizontal synchronous signal H.sync, The light emitting portion 11 is turned off because it is cut off by the capacitor C11 and is not applied to the light emitting portion 11. [

That is, since the light emitting unit 11 and the light receiving unit 12 of the sensing means 10 are turned off and a low level control signal is applied to the switching unit 20, Level is applied and the rectified voltage outputted from the bridge diode 63 becomes lower than the peak voltage accumulated in the second capacitor C12, the SCR 21 is turned off and the high level is applied to the gate terminal G Off state until it is turned on.

When the SCR 21 is turned off as described above, since the rectified voltage output from the bridge diode 63 is not applied to the SMPS 1, the SMPS 1 stops driving, Since the driving voltage is not supplied, the microcomputer stops driving.

4, when the normal mode is set again,

When a normal horizontal synchronizing signal H.sync is outputted from the PC in the state where the microcomputer is not driven as described above, the horizontal synchronizing signal H.sync is rectified by the resistor R and the first capacitor C11, The second transistor TR2 and the third transistor TR3 are sequentially turned on so that the SCR 21 is turned on and the bridge diode 63 is turned on, The SMPS 1 is driven in a steady state.

That is, even if the microcomputer stops driving, when the normal horizontal synchronizing signal H.sync is inputted, the SMPS 1 starts to drive again and supplies the driving voltage required by each part of the monitor.

As described above, according to the present invention, even if the microcomputer stops driving during the off mode of the monitor, if there is a horizontal synchronizing signal input from the PC, the SMPS is driven again, There is an effect that can be greatly reduced.

Claims (7)

A power supply circuit for a monitor which rectifies input AC power from a bridge diode (63) and applies the rectified voltage to the SMPS (1) to supply necessary voltages to the respective parts of the monitor through the SMPS (1) A sensing means 10 for sensing when the monitor enters the off mode, And a switching unit (20) for switching the sensing unit to prevent the rectified voltage from being applied to the SMPS when the sensing unit detects that the monitor is in the off mode and outputs a high level control signal, And the SMPS stops driving when the monitor enters the off mode. 2. The apparatus according to claim 1, wherein the sensing means comprises: a light emitting portion (11) for conducting and emitting light when a normal horizontal synchronizing signal is inputted from a PC; And a light receiving unit (12) which conducts when the light emitting unit emits light and outputs a high level control signal to the switching unit. 3. The apparatus according to claim 2, wherein the sensing means (10) receives an OFF control signal (OFF) of a high level outputted from the microcomputer when the monitor is in the normal mode or the suspend mode, And a first transistor (TR1) for allowing the first transistor (TR1) to be turned on. The power supply circuit of an ultra-miniature monitor according to claim 2, wherein the sensing means (10) comprises a Zener diode (D1) for controlling the voltage applied to the light receiving unit (12) to be constant. The apparatus according to claim 2, wherein when the horizontal synchronization signal (H.sync), which is a high level DC signal, is input from the PC in the off mode of the monitor, the sensing means (10) And a first capacitor (C11) for blocking the first capacitor (C11) from being applied to the power supply circuit. 2. The method of claim 1, wherein when the control unit outputs a high level control signal from the sensing unit, the switching unit applies a high level to the gate terminal G and a rectified voltage to the anode terminal A And an SCR (21) connected to the cathode terminal (K) and the SMPS (1). The switching power supply according to claim 6, wherein the switching unit (20) is connected between the cathode terminal (K) of the SCR (21) and the SMPS (1) and accumulates the peak voltage of the rectified voltage while the SCR And a second capacitor (C12) When the gate terminal G of the SCR 21 transitions to the low level and the rectified voltage becomes lower than the peak voltage accumulated in the second capacitor C12, the SCR 21 is turned off Power supply circuit of ultra low power monitor.