KR19990003849A - Monitor power circuit - Google Patents

Abstract

The present invention relates to a power supply circuit for a monitor, comprising: a bridge diode for rectifying an input AC power to output a rectified voltage; a control IC for turning on / off a power transistor while operating with the rectified voltage; And a transformer for supplying a necessary voltage to each part of the monitor through the secondary winding when the monitor is off, the power circuit comprising: a microcomputer for outputting a low level power saving signal when the monitor is in a power saving mode; A switching unit 10 for disconnecting at least two power supply voltages applied to the video circuit from the low-level power saving signal output from the power supply unit and disconnecting the lower power supply voltage from the power supply voltage, and a horizontal deflection circuit and a microcomputer It senses the power supply voltage of 15V and feeds it back to the control IC. And a power supply voltage control unit (20) for sensing the B + voltage applied to the horizontal deflection circuit and feeding back the voltage to the control IC when the monitor is in the power save mode, The power consumption can be greatly reduced by cutting off some of the power supply voltages outputted from the windings. In the power saving mode as described above, the high voltage B + voltage is fed back to the control IC while sensing the voltage, There is an effect that can be.

Description

A power supply of a monitor

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a power supply circuit of a power saving monitor, and more particularly, to a power supply circuit of a power saving 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 refers to the power management processor of a computer set by Microsoft and IBM.

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 to the bridge diode 63 and the control IC 67 in such a manner that the high- Block outgoing. The AC voltage that has passed through the line filter L1 and the Y capacitor C2 is rectified by the bridge diode 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 63 is supplied 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 outputs the AC voltage (for example, .

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 , 200V) and supplied to the horizontal / vertical deflection unit, the video amplifier, and the heater H of the CRT to operate the circuit.

Meanwhile, the 15V power supply voltage is branched and applied to the power saving mode control unit 50. The power saving mode control unit 50 receives the power saving signal of high level from the microcomputer in the normal mode, and the first transistor 11 is turned on , The power supply voltage of 15V is input 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, the collector terminal of the first transistor Q1 and the base terminal of the second transistor Q2 are connected in parallel so that the current passing through the Zener diode D4 flows only to 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 power supply voltage outputted from the power supply unit 60 is supplied to the horizontal / vertical deflection unit, the video amplifier and the heater as it is and operates normally.

However, when the low-level power saving signal is input from the microcomputer to the power saving mode controller 50 in the suspend mode or the off mode, the first transistor Q1 is turned off, so that the voltage passing through the Zener diode D4 1 transistor Q1 and is applied to the base end of the second transistor Q2.

Accordingly, the second transistor Q2 is turned on and the 15V 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, 69-2) located between the output terminal of the power supply unit (60) and the collector terminal of the second transistor (Q2) than in the normal mode, (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 15V.

While the low-level power saving signal is input from the microcomputer, the process is repeatedly performed to reduce the power saving voltage level to less than 30% of the predetermined power saving voltage level, that is, 15V, and supplies the power to the horizontal / vertical deflection unit and the audio amplifier.

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, in the power supply circuit of the power saving monitor realized by the output voltage drop method as described above, the circuit for obtaining the voltage required by the secondary side of the transformer in the power saving mode becomes complicated, and even in the power saving mode, There is a problem that the power consumption can not be reduced to a certain level or less because the voltage is outputted.

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 provide a power saving mode in which a power supply voltage, which is not needed at a secondary side of a transformer, And a power supply circuit of a power-saving type monitor.

According to an aspect of the present invention, there is provided an apparatus including a bridge diode for rectifying an input AC power to output a rectified voltage, a control IC for turning on / off a power transistor while operating with the rectified voltage, And a transformer for supplying a necessary voltage to each part of the monitor through the secondary winding during on / off,

A microcomputer for outputting a low-level power saving signal when the monitor is in the power saving mode,

A switching unit that receives a low-level power saving signal output from the microcomputer and disconnects at least two power supply voltages applied to the video circuit and its negative ends,

When the monitor is in the normal mode, the power supply voltage of 15V applied to the horizontal deflection circuit and the micom is sensed and fed back to the control IC. When the monitor is in the power saving mode, the B + voltage applied to the horizontal deflection circuit is sensed, And a power supply voltage control unit for feeding back the power supply voltage.

1 is a circuit diagram showing a power supply circuit of a general monitor,

2 is a circuit diagram showing a power supply circuit of a monitor according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

61: power supply input unit 62: input filter unit

63: bridge diode 65: transformer

66: Power transistor 67: Control IC

10: Switching section 20: Power supply voltage control section

21: light emitting element 22: light receiving element

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 a monitor according to the present invention, which includes a power input unit 61 to which a commercial input AC power of 110 V or 220 V is applied through a fuse, A bridge diode 63 for rectifying and rectifying the input AC power to output a rectified voltage and a control IC 67 for turning on and off the power transistor 66 while operating by the rectified voltage A transformer 65 for supplying a necessary voltage to each part of the monitor through the secondary side winding while the power transistor 66 is turned on and off, and a low-level power saving signal when the monitor is in the power saving mode output and the microcomputer, at least two power supply voltage receives the sleep signal of a low level is output from the microprocessor is applied to a video circuit for (V _a, V _B, ...) with its lower end portion is connected to the car When the monitor is in the normal mode, the power supply voltage of 15V applied to the horizontal deflection circuit and the micom is sensed and fed back to the control IC 67. In addition, when the monitor is in the power saving mode, it is applied to the horizontal deflection circuit And a power supply voltage control unit 20 that senses the B + voltage and feeds back the voltage to the control IC 67.

Here, the switching unit 10 is applied a power saving signal of high level, turning on the eleventh transistor (Q11) and the first transistor is turned on when one is turned on at least two or more supply voltages (V _A is, V _B, ...) and the twelfth transistor (Q12) for connecting its portion at the bottom, the first 11 of the eleventh resistor (R11) connected between the base end and the emitter teodan of the transistor (Q11), and the twelfth transistor (Q12 And a twelfth resistor R12 connected between the base end and the emitter end.

The power supply voltage control unit 20 includes a 15V sensing unit for sensing a power supply voltage of 15V when the monitor is in a normal mode and outputting the sensing voltage to a feedback unit, a B + sensing unit for sensing a B + voltage when the monitor is in a power saving mode, A B + switch for controlling the driving of the B + sensing unit to be turned on / off according to a mode of the monitor; and a control IC 67 for, when the power supply voltage of 15V rises excessively or the B + voltage rises excessively, So that the secondary side voltage of the transformer 65 is lowered.

The 15V sensing unit includes a twenty-first transistor Q21 turned on by a high level power saving signal, a twenty-first resistor R21 connected between the collector terminal of the twenty-first transistor Q21 and the 15V line, A twenty-second resistor R22 connected between the emitter terminal and the ground terminal of the transistor Q21 and a zener diode ZD turned on when the voltage applied to the twenty-second resistor R22 is higher than the Zener voltage .

The B + switching unit includes a twenty-second transistor Q22 turned on by a high level power saving signal, a twenty-fifth resistor R25 connected between a base end and an emitter end of the twenty-second transistor Q22, And a 26th resistor R26 connected between the collector terminal of the transistor Q22 and the 15V line.

The B + sensing unit includes a twenty-third transistor Q23 turned on inversely with the twenty-second transistor Q22, a twenty-third resistor R23 connected between the collector terminal of the twenty-third transistor Q23 and the B + line, A twenty-second resistor R22 connected between the emitter terminal and the ground terminal of the twenty-third transistor Q23, and a zener diode ZD (ZD), which is turned on when the voltage applied to the twenty- ).

The feedback unit includes a light emitting device 21 that emits light when the power supply voltage of 15V rises excessively or when the B + voltage rises excessively, and a control IC 67 that photoelectrically converts light output from the light emitting device 21, And a light receiving element 22 applied to a feed back end Vfb of the photoreceptor.

The operation and effect of the present invention configured as described above will now be described in more detail by dividing the monitor into a normal mode and a power saving mode.

1, when the monitor is in the normal mode,

The general operation states of the power input unit 61, the input filter unit 62, the bridge diode 63, the control IC 67, the power transistor 66 and the transformer 65 used in the present invention are the same as those in the prior art Therefore, the description thereof will be omitted in the present invention, and only a part necessary for explaining the new technology of the present invention will be described as necessary.

When the monitor is in the normal mode, the microcomputer outputs a high level power saving signal. The eleventh transistor Q11 is turned on by the high level power saving signal, and when the eleventh transistor Q11 is turned on 12 current flows through the resistor R12. When the voltage applied to the 12th resistor R12 exceeds 0.7 V, the 12th transistor Q12 is turned on.

When the twelfth transistor Q12 is turned on, the power supply voltages V _A , V _B ,... Outputted from the transformer 65 are connected to the lower ends of the transistors, and the circuits of the monitor normally operate.

Meanwhile, the high level power saving signal is applied to the base end of the twenty first transistor Q21 and the base end of the twenty second transistor Q22, and the twenty first transistor Q21 and the twenty second transistor Q22 are turned on do.

When the twenty-second transistor Q22 is turned on, the emitter terminal of the twenty-second transistor Q22 is grounded while the 15-V power supply voltage is applied to the twenty-sixth resistor R26. And the 23rd transistor Q23 is turned off.

At the same time, when the 21st transistor Q21 is turned on, the 15V power supply voltage is branched by the 21st resistor R21 and the 22nd resistor R22, If the voltage applied to the photodiode R22 is lower than the zener voltage of the zener diode ZD, the zener diode ZD is turned off, so that the current does not flow to the phototransistor 21.

However, when the 15V power supply voltage is excessively increased beyond the normal value, the voltage applied to the 22nd resistor R22 becomes higher than the Zener voltage of the Zener diode ZD, and the Zener diode ZD is turned on, The current flows to the light emitting element 21 of the photocoupler.

When a current flows to the light emitting element 21 as described above and the light emitting element 21 emits light, an overcurrent flows to the feed back end Vfb of the control IC 67 through the light receiving element 22, The inverter 67 outputs a PWM signal having a short on-time, thereby lowering the power supply voltage output from the secondary winding of the transformer 65. [

That is, when the power supply voltage output from the secondary winding of the transformer 65 becomes high, the 15V power supply voltage is sensed and fed back to the control IC 67. The control IC 67 controls the PWM And outputs it to the power transistor 66 so that the power supply voltage output from the secondary winding of the transformer 65 is in a steady state.

2, When the monitor is in power save mode,

When the monitor is in the power saving mode, the microcomputer outputs a low level power saving signal. When the low level power saving signal is inputted to the switching unit 10, the eleventh transistor Q11 and the twelfth transistor Q12 turn The connection of the power supply voltage (V _A , V _B , ...) output from the secondary winding of the transformer 65 and its negative terminal is cut off.

At this time, the B + voltage applied to the horizontal deflection circuit and the 15V power supply voltage supplying power to the microcomputer remain connected to their load stages, respectively. This is because, in the power saving mode, This is because it is not necessary to switch and the 15V power supply voltage is necessary for driving the microcomputer.

As mentioned above, since the negative terminal of the B + voltage does not consume power in the power saving mode, the magnitude of the B + voltage becomes higher than the normal value. If the B + voltage becomes excessively high, the horizontal deflection circuit is adversely affected.

Therefore, it is necessary to control this to a certain level. This is because, when the low-level power saving signal is inputted to the base end of the twenty-second transistor Q22 in the power saving mode, the twenty-second transistor Q22 is turned off, When the transistor 22 is turned off, a 15V power supply voltage is applied to the base end of the 23rd transistor Q23 through the 26th resistor R26 to turn on the 23rd transistor Q23.

The low level power saving signal is applied to the base end of the twenty first transistor Q21 so that the twenty first transistor Q21 is turned off and the 15V power supply voltage can not flow to the twenty first resistor R21.

When the 23rd transistor Q23 is turned on, the B + voltage is grounded after passing through the 23rd resistor R23, the 23rd transistor Q23 and the 22nd resistor R22, Is lower than the Zener voltage, the Zener diode ZD is turned off.

However, when the B + voltage excessively rises and the voltage applied to the twenty-second resistor Q22 becomes higher than the Zener voltage, the Zener diode ZD is turned on and a 15V power supply voltage flows to the light emitting device 21, The element 21 emits light.

When the light emitting element 21 emits light, it is input to the feedback stage Vfb of the control IC 67 through the light receiving element 22. The control IC 67 outputs a PWM signal having a short on-time, So that the power supply voltage output from the secondary winding of the inverter 65 becomes a normal state.

As described above, according to the present invention, when the monitor is in the power saving mode, it is possible to significantly reduce the power consumption by shutting off some of the power source voltages among the power source voltages outputted from the secondary side winding of the transformer. In such a power saving mode, The B + voltage is fed back to the control IC while sensing the B + voltage, so that a more stable B + voltage can be obtained.

Claims (6)

A control IC for turning on / off the power transistor while operating by the rectified voltage, and a control IC for controlling the angle of the monitor through the secondary side winding while the power transistor is on / The power supply circuit of a monitor including a transformer for supplying a necessary voltage to the power supply unit, the power supply circuit comprising: a microcomputer for outputting a low-level power saving signal when the monitor is in a power saving mode; A switching unit 10 for disconnecting at least two power supply voltages applied to the video circuit and a negative terminal thereof, and a controller 15 for sensing a power supply voltage of 15 V applied to the horizontal deflection circuit and the microcomputer when the monitor is in a normal mode, And when the monitor is in the power saving mode, the B + voltage applied to the horizontal deflection circuit Sensing the power of the monitor circuit according to and characterized by consisting of a power supply voltage control unit 20 for feedback to the control IC. The power supply according to claim 1, wherein the switching unit (10) comprises: an eleventh transistor (Q11) turned on when a high level power saving signal is applied; And a twelfth transistor (Q12) for connecting the negative terminal of the first transistor and the negative terminal of the second transistor. The apparatus of claim 1, wherein the power supply voltage control unit (20) comprises: a 15V sensing unit sensing a power supply voltage of 15V when the monitor is in a normal mode and outputting the sensed power supply voltage to a feedback unit; A B + sensing unit for outputting the B + voltage to the B + sensing unit, and a B + switch for controlling the B + sensing unit to be turned on / off according to the mode of the monitor. When the power voltage of 15V rises excessively or the B + And the feedback circuit is fed back to the IC so that the secondary side voltage of the transformer is lowered. The semiconductor device according to claim 3, wherein the 15V sensing unit comprises: a twenty-first transistor (Q21) turned on by a high level power saving signal; a twenty-first resistor (R21) connected between a collector terminal of the twenty- A twenty-second resistor R22 connected between the emitter terminal and the ground terminal of the twenty-first transistor, and a Zener diode ZD turned on when the voltage applied to the twenty-second resistor is higher than the Zener voltage. The power supply circuit of the monitor. The semiconductor memory device according to claim 3, wherein the B + switching unit includes a twenty-second transistor (Q22) turned on by a high level power saving signal, and the B + sensing unit includes a twenty-third transistor A second resistor R22 connected between the emitter terminal and the ground terminal of the thirteenth transistor; a third resistor R22 connected between the collector terminal and the B + And a Zener diode (ZD) that is turned on when the voltage applied to the twenty second resistor becomes higher than the Zener voltage. The organic light emitting display as claimed in claim 3, wherein the feedback unit comprises: a light emitting device (21) which emits light when the power supply voltage of 15V rises excessively or when the B + voltage rises excessively; And a photocoupler composed of a light receiving element (22) applied to a feed back end of the IC.