GB2343823A - Power saving circuit for computer monitor has separate power supply and control for CRT heater - Google Patents

Power saving circuit for computer monitor has separate power supply and control for CRT heater Download PDF

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Publication number
GB2343823A
GB2343823A GB9926852A GB9926852A GB2343823A GB 2343823 A GB2343823 A GB 2343823A GB 9926852 A GB9926852 A GB 9926852A GB 9926852 A GB9926852 A GB 9926852A GB 2343823 A GB2343823 A GB 2343823A
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United Kingdom
Prior art keywords
power
monitor
voltage
circuit
controller
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Granted
Application number
GB9926852A
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GB2343823B (en
GB9926852D0 (en
Inventor
Yeo Sung Yun
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LG Electronics Inc
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LG Electronics Inc
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Publication of GB2343823A publication Critical patent/GB2343823A/en
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Publication of GB2343823B publication Critical patent/GB2343823B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/26—Power supply means, e.g. regulation thereof
    • G06F1/32—Means for saving power
    • G06F1/3203—Power management, i.e. event-based initiation of a power-saving mode
    • G06F1/3206—Monitoring of events, devices or parameters that trigger a change in power modality
    • G06F1/3215—Monitoring of peripheral devices
    • G06F1/3218—Monitoring of peripheral devices of display devices
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/26—Power supply means, e.g. regulation thereof
    • G06F1/32—Means for saving power
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/26—Power supply means, e.g. regulation thereof
    • G06F1/32—Means for saving power
    • G06F1/3203—Power management, i.e. event-based initiation of a power-saving mode
    • G06F1/3234—Power saving characterised by the action undertaken
    • G06F1/325—Power saving in peripheral device
    • G06F1/3265—Power saving in display device
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/021—Power management, e.g. power saving
    • G09G2330/022—Power management, e.g. power saving in absence of operation, e.g. no data being entered during a predetermined time
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0032—Control circuits allowing low power mode operation, e.g. in standby mode
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/50—Reducing energy consumption in communication networks in wire-line communication networks, e.g. low power modes or reduced link rate

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Controls And Circuits For Display Device (AREA)
  • Control Of Voltage And Current In General (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

A PC monitor includes a power saving circuit comprising: a DC power supply, a first transformer to provide a first power supply, a second transformer to provide a power supply for the Cathode Ray Tube heater, and a computer means to generate a control signal dependant on the mode of the monitor. In a normal mode both first and second power supplies are energised, if the monitor is idle for a period the first supply is switched off, if the monitor is idle for a further period the second supply is also switched off.

Description

POWER SAVING CIRCUIT AND METHOD FOR A MONITOR The present invention relates to a power saving circuit and method for a monitor, and more particularly, to a power saving circuit and method which is capable of automatically turning off main power to the monitor in accordance with a plurality of display power management (hereinafter, referred to as 'DPM') signals, when a computer does not operate for a predetermined period of time.
Generally, a power saving circuit of a monitor is automatically changed into a power saving mode, when a computer does not operate for a predetermined time period. It cuts off the power supplied to the monitor until key manipulation is restarted by a user, to thereby reduce unnecessary power consumption. Monitors, which have been recently sold in the market, adopt such a power saving function, but since the reliability between the monitor and the computer in the power saving mode should be essentially ensured, research into enhanced quality power saving on the monitor has continued.
FIG. 1 is a block diagram illustrating the construction of a conventional monitor power circuit.
As shown, in construction, the conventional monitor power circuit includes: a power input part 1 for decreasing the voltage of input power (AC); a noise filter 2 for inputting an output voltage of the power input part 1, if a main power switch SW1 is turned on, to thereby eliminate noise in the output voltage; a rectifying and smoothing part 3 for rectifying and smoothing the output voltage of the noise filter 2 by using a bridge diode BD 1 and a condenser C 1 to thereby convert the output voltage into a DC voltage Vd and for dividing the DC voltage Vd by means of resistors R1 to R3 to thereby output the divided voltage; a power switching part 4 for outputting a switching signal by means of the divided voltage V1 of the rectifying and smoothing part 3; and a voltage output part 5 for inducing the output of the rectifying and smoothing part 3 to a secondary side of a transformer T1 in accordance with the switching signal of the power switching part 4, to thereby output a plurality of voltages (+B 1, +B2, +B3,...) having different levels and an operation voltage to a microcomputer of the monitor. Herein, a reference numeral'C2'denotes a condenser.
Under the above construction, when the voltage of the input power (AC) is decreased through the power input part 1, the main power switch SW1 is turned on, and the noise filter 2 then inputs the output voltage of the power input part 1 and eliminates the power noise to thereby output the noise eliminated voltage to the rectifying and smoothing part 3.
At this time, the output voltage of the noise filter 2 is rectified by means of the bridge diode BD1 of the rectifying and smoothing part 3 and then smoothed by means of the condenser Cl thereof to the DC voltage Vd, to thereby output the DC voltage Vd to a primary side of the transformer T1 of the power output part 5. The DC voltage is divided by means of the resistors R1 and R2 and the ground resistors R3 and is outputted as the divided voltage VI to the power switching part 4 through the condenser C2.
As a switching transistor (not shown) in the power switching part is repeatedly turned on/off, the DC voltage of the rectifying and smoothing part 3, which has been applied to the primary side of the transformer T1 of the power output part 5, is induced to the secondary side of the transformer T1 to be thereby outputted as the plurality of voltages having different levels and as the operation voltages of the microcomputer of the monitor.
The conventional monitor power circuit has, however, the following disadvantages: firstly, the power consumption is continued unless the power of monitor is turned off, in the case where the computer does not operate, which fails to prevent unnecessary power consumption; and secondly, since the power supply is continued even in the case where the monitor is not used, the life span of devices within the circuit is reduced to thereby degrade the reliability of the power circuit.
Accordingly, the present invention is directed to a power saving circuit and method for a monitor that substantially obviates one or more of the problems due to limitations and disadvantages of the prior art.
An object of the invention is to provide a power saving circuit and method which is capable of automatically turning off main power and/or heater power of the monitor in accordance with a plurality of DPM signals, in the case where a computer does not operate for a predetermined period of time, thereby reducing power consumed in the monitor.
Another object of the invention is to provide a power saving circuit and method which does not need any separate circuit for the supply of power to a microcomputer in a power saving mode, thereby reducing production costs.
According to an aspect of the present invention, there is provided a power saving circuit of a monitor including: a power supply part for supplying a direct current (DC) power; a first transformation part for inputting the DC power to thereby output a plurality of different voltages; a second transformation part for inputting the DC power to thereby supply microcomputer power, heater power and the operation power of the first transformation part; a microcomputer for determining a normal mode and a power saving mode in accordance with a video signal of equipment connected to the monitor to thereby output a control signal; a first power saving part for controlling the operation of the first transformation part in accordance with the control signal of the microcomputer; and a second power saving part for cutting the heater power outputted from the second transformer part in accordance with the control signal of the microcomputer.
According to another aspect of the present invention, there is provided a power saving method for a monitor having a first transformation part for supplying a plurality of voltages and a second transformation part for supplying heater power, comprising the steps of : if the input of a video signal is continued from a computer, operating the first and second transformation parts; if the input of the video signal is not generated for a first time period, stopping the operation of the first transformation part; and if the input of the video signal is not generated for a second time period, stopping the heater power.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the drawings.
In the drawings: FIG. 1 is a block diagram illustrating the construction of a conventional monitor power circuit; FIG. 2 is a block diagram illustrating a power saving circuit of a monitor according to the present invention; FIG. 3 is a detailed circuit diagram illustrating the main parts of FIG. 2 ; FIG. 4 is an exemplary diagram illustrating the voltage output state by operation modes in FIG. 2; and FIG. 5 is a flowchart illustrating an operation order of the power saving circuit of the monitor according to the present invention.
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
FIG. 2 is a block diagram illustrating a power saving circuit of a monitor according to the present invention, and FIG. 3 is a detailed circuit diagram illustrating the main parts of FIG. 2.
Firstly, the monitor power saving circuit according to the present invention includes: a power supply part 20 for supplying direct current (DC); a first transformer part 30 for receiving the DC power to output a plurality of different voltages; a second transformer part 40 for receiving the DC power to output it as microcomputer power, heater power and operation power for the first transformation part 30; a microcomputer 18 for determining a normal mode and a power saving mode in accordance with a video signal from equipments connecte to the monitor and for outputting a control signal ; a first power saving part 14 (a main power switching part) for controlling the operating of the first transformation part 30 in accordance with the control signal of the microcomputer 18; and a second power saving part 16 (a switching part) for cutting the heater power outputted from the second transformation part 40 in accordance with the control signal of the microcomputer 18.
A rectifier 11 rectifies and smoothes the AC power (e. g. AC 100-220V) inputted to output the DC. A power factor controller 12 compensates a power factor of the DC voltage to output the compensated voltage as the start operation voltages of a main power controller and a subpower controller. The compensated voltage is applied to a primary coil of the main transformer T1 and the subtransformer T2. The main transformer T1 receives the DC voltage from the power factor controller 12 at the primary side coil and outputs the plurality of different voltages (+B1, +B2, +B3, +B4,...) in accordance with the winding ratio of the coils. The main power controller 13 controls the operation of the main transformer T1 with the DC voltage from the power factor controller 12 as the initial start operation power. The subtransformer T2 receives the DC voltage from the power factor controller 12 at the primary coil to produce the microcomputer power and the heater power through the secondary coil. The controller 12 also provides the operational voltage of the main power controller 13 and the subpower controller 15. The subpower controller 15 receives the start operation voltage from the power factor controller 12 to control the operation of the subtransformer T2. A subpower switching part 17 rectifies and smoothes the output voltage of the subtransformer T2 and supplies the rectified and smoothed DC power as the operation voltage Vcc to the subpower controller 15 by means of an external control signal. The microcomputer 18 controls the overall power circuit and outputs first and second DPM control signals in a power saving mode in accordance with the existence/non-existence of the video signal (horizontal/vertical synchronizing signals) from the computer. The switching part 16 turns on/off the heater power from the subtransformer T2 in accordance with a first DPM control signal from the microcomputer 18. The main power switching part 14 receives the power from the subtransformer T2 to thereby supply or cut the operation voltage of the main power controller 13 in accordance with a second DPM control signal from the microcomputer 18.
In this case, each of the main power controller 13 and the subpower controller 15 includes a switching mode power supply (SMPS) function for inducting the DC voltage applied to the primary side coil of each transformer T1 and T2 to the secondary side coil thereof.
FIG. 3 is a detailed circuit diagram illustrating the main parts of FIG. 2.
In more detail, the main transformer T1 outputs the plurality of different voltages in accordance with the winding ratio of the coils in which a constant voltage integrated circuit 19 is installed to output a voltage of 12V.
The subtransformer T2 inputs the DC voltage from the power controller 12 to the primary coil to output the microcomputer power +B7 and the heater power +Bg through the secondary coil to induce the voltage of the secondary coil to output the operation voltage Vcc of the main power controller 13 and the subpower controller 15.
The subpower switching part 17 comprises a diode D2, a capacitor C3, and a photocoupler (a light emitting diode PD1 and a light receiving transistor PR1). If the microcomputer power +B7 is outputted from the subtransformer T2, the light emitting diode PD1 causes the transistor PT1 to conduct, such that the operation voltage of the subpower controller 15 is continuously supplied.
The main power switching part 14 is constituted by a diode D1 and a condenser Cl and includes a rectifier and smoother 14a for rectifying and smoothing the output voltage of the subtransformer T2, a switch 14b comprised of a light emitting diode PD2, a light receiving transistor PT2, resistors R2, R2, R4 and a switching transistor Ql for supplying the DC voltage of the rectifier and smoother 14a as the operation voltage Vcc to the main power controller 13 in accordance with the output signal of the microcomputer 18. A stabilizer 14c comprised of a capacitor C2 and a Zener diode ZDI stabilizes the outpower power from the switch 14b. In this case, the switching transistor Q1 is a PNP transistor.
An explanation of operation of the monitor power saving circuit of the present invention will be discussed with reference to FIGS. 4 and 5.
FIG. 4 illustrates the voltage output state by operation modes in FIG. 2.
FIG. 5 is a flowchart illustrating the operational order of the power saving mode. The first and second DPM control signals DPMI and DPM2 are outputted at the logic"high"state. In the stand-by mode the second DPM control signal DPM2 is outputted at the logic"low"state. In the off mode the first and second DPM control signals DPM1 and DPM2 are outputted at the logic"low"state.
The input AC power is rectified and smoothed to the DC voltage by means of the rectifier 11. The DC voltage is power factor-compensated by means of the power factor controller 12 and applied to the main transformer T1 and the subtransformer T2 and as the start voltage to the main power controller 13 and the subpower controller 15, respectively.
The main transformer T1 is operated under the control of the main power controller 13 to provide the plurality of different voltages +Bl, +B2, +B3, +B4, +B5, +B6.
On the other hand, the subtransformer T2 changes the voltage of the power factor controller 12 by means of the subpower controller 15 to provide the microcomputer power +B7 and the heater power +Bg and the operation voltage Vcc of the main power controller 13 and the subpower controller 15.
At this time, upon the normal mode, the microcomputer 18 outputs the first and second DPM control signals at the logic ; high level. As a result, the switching part 16 supplies the heater power +B ; outputted from the subtransformer T2 to the heater in response to the first DPM control signal.
The main power switching part 14 operates the light emitting diode PD2 in response to the second DPM control signal to turn on the light receiving transistor PT2. Thus, a bias current is supplied to the base of the switching transistor Ql to turn it on. Hence, the DC voltage outputted from the rectifier and smoother 14a is applied to the main power controller 13, such that the main transformer Tl outputs the plurality of power supply voltages +Bl, +B2, +B ;, +B4, +B5, +B6 in accordance with the switching operation of the main power controller 13.
During the above process, if the horizontal and vertical synchronizing signals are not inputted for a predetermined time period from the computer, the microcomputer 18 determines the state as suitable for the stand-by mode.
For the stand-by mode, the microcomputer 18 outputs the first DPM control signal at the logic"high"level and the second DPM control signal at the logic"low"level, respectively. As a result, the switching part 16 continually supplies the heater power +Bg in response to the first DPM control signal, and the main power switching part 14 does not operate the light emitting diode PD2.
The light receiving transistor PT2 is kept off. The bias current is not supplied to the base of the switching transistor Q 1, keeping off the switching transistor Ql.
Hence, the operation power Vcc is not supplied to the main power controller 13, such that the main power controller 13 does not execute the switching operation to operate the main transformer T1. There is no voltage output from the secondary side of the main transformer T 1.
During the above process, if the horizontal and vertical synchronizing signals are not inputted over a predetermined time period from the computer, the microcomputer 18 then determines if it is appropriate for the off mode.
In the off mode, the microcomputer 18 outputs the first and second DPM control signals at the logic"low"level. As a result, the switching part 16 cuts the supply of the heater power +B8 in response to the first DPM control signal, and the main power switching part 14 does not operate the light emitting diode PD2, thereby turning off the light receiving transistor PT2. Thus, the bias current is not supplied to the base of the switching transistor Ql keeping the switching transistor Q 1 turned off.
Hence, the operation power Vcc is not supplied to the main power controller 13, such that the main power controller 13 does not execute the switching operation to operate the main transformer T1. There is no voltage output from the secondary side of the main transformer T 1.
At this time, irrespective of the DPM control signal, the subpower controller 15 operates the subtransformer T2. In other words, since the light emitting diode PD 1 of the subpower switching part 15 is operated, the operation power Vcc is continually supplied to the subpower controller 15, and the subtransformer T2 outputs the microcomputer power +B7 to thereby prevent crashing of the power circuit.
As discussed above, a monitor power saving circuit and method of the present invention has the following advantages: Firstly, it can reduce power consumption because of a selective output of the heater power.
Secondly, it does not need any separate circuit for operating power for the microcomputer, thereby reducing production costs, because the subtransformer continually supplies the operation power for the microcomputer even in the power saving mode.
Thirdly, because of the cut-off of the heater power, it can satisfy the standard of 3W in the power saving mode of ultra-power saving energy 2000 international standard and add a USB (universal serial bus) function.
The monitor power saving circuit of the present invention can be the subject of various modifications and variations without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (9)

  1. CLAIMS 1. A power saving circuit for a monitor, comprising: power supply means for supplying DC power; first transformation means for deriving a plurality of voltages from the DC power; second transformation means for deriving a monitor heater supply from the DC power; computer means for determining a normal mode and a power saving mode of the monitor and operable to generate a control signal in accordance with the mode; first power saving means for controlling the operation of the transformation means in accordance with the control signal; and second power saving means for controlling the heater supply from the second transformation means in accordance with the control signal.
  2. 2. The circuit as defined in claim 1, wherein the power supply part comprises a rectifier for rectifying and smoothing AC power to output the DC power, and a power factor controller for compensating a power factor of the DC power to provide compensated DC power.
  3. 3. The circuit as defined in claim 1 or 2, wherein the first transformation means comprises a main transformer for receiving the DC power from the power supply means to drive the plurality of voltages, and a main power controller for controlling the operation of said main transformer.
  4. 4. The circuit as defined in claim 1, 2 or 3 wherein the second transformation part comprises a subtransformer for receiving the DC power from the power supply means to drive the heater power and further to derive microcomputer power and an operational voltage for the first and second transformation means, a subpower controller for receiving a start operation voltage from the power supply means to control the operation of the said subtransformer, and subpower switching means for rectifying and smoothing the output voltage of the subtransformer to produce an operational voltage for the subpower controller.
  5. 5. The circuit as defined in claim 4, wherein the subpower switching means is synchronized to the microcomputer power outputted from the subtransformer to supply the operational voltage of the subpower controller
  6. 6. The circuit as defined in any of claims 1 to 5, wherein the first power saving means comprise a photocoupler operable in accordance with the control signal of the microcomputer, and a main power switching means for supplying the DC power to the first transformation means in accordance with the operation of said photocoupler.
  7. 7. The circuit as defined in claim 6, wherein the main power switching means comprises a rectifier and smoother for rectifying and smoothing the output voltage of the subtransformer, a switch for supplying the output of the rectifier and smoother as the operational voltage of the first transformation means in accordance with the output of the photocoupler, and a stabilizer for stabilizing the output power from the switch.
  8. 8. A power saving method for a monitor having first transformation means for supplying a plurality of voltages and a second transformation means for supplying heater power, comprising the steps of : if a video signal is passed to the monitor, operating the first and second transformation means; if the video signal is not generated for a first period, stopping operation of the first transformation means; and if the video signal is not generated for a second period, stopping the heater power.
  9. 9. The method as defined in claim 8, where the video signal comprises horizontal and vertical synchronizing signals.
GB9926852A 1998-11-12 1999-11-12 Power saving circuit and method for a monitor Expired - Fee Related GB2343823B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1019980048370A KR100282333B1 (en) 1998-11-12 1998-11-12 Monitor power-saving circuit

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Publication Number Publication Date
GB9926852D0 GB9926852D0 (en) 2000-01-12
GB2343823A true GB2343823A (en) 2000-05-17
GB2343823B GB2343823B (en) 2001-01-10

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JP (1) JP3471683B2 (en)
KR (1) KR100282333B1 (en)
CN (1) CN1112627C (en)
BR (1) BR9907513A (en)
GB (1) GB2343823B (en)
ID (1) ID24865A (en)
MX (1) MXPA99010360A (en)

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EP1420332A2 (en) * 2002-11-15 2004-05-19 LG Electronics Inc. Power controlling system
US9513683B2 (en) 2011-12-14 2016-12-06 Universal Scientific Industrial (Shanghai) Co., Ltd. Control circuitry used in a computing system, and power supply having the control circuitry

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Publication number Priority date Publication date Assignee Title
KR100332043B1 (en) * 2000-07-04 2002-04-10 구자홍 Circuit for stabilization voltage of video appliance on display power management mode
JP4601186B2 (en) * 2001-02-19 2010-12-22 シャープ株式会社 Display device
KR100839851B1 (en) * 2001-10-17 2008-06-19 엘지전자 주식회사 Circuit for power supply
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CN1254117A (en) 2000-05-24
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BR9907513A (en) 2000-09-05
ID24865A (en) 2000-08-31
MXPA99010360A (en) 2005-07-25
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KR100282333B1 (en) 2001-03-02
KR20000032045A (en) 2000-06-05

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