KR0161136B1 - Power supply circuit - Google Patents

Abstract

The present invention provides an auxiliary winding unit for outputting a voltage 10 times higher than the winding unit of the main voltage output circuit in order to be able to supply a stable power to the internal circuit of the electronic device that requires the same power supply voltage in the power saving mode; A voltage transfer unit for supplying an output voltage of the auxiliary winding unit to an output terminal in a power saving mode, a voltage transfer control unit for controlling an operation of the voltage transfer unit by sensing a voltage change of the output terminal, and a voltage transfer unit and a voltage transfer control unit. The auxiliary voltage output circuit is implemented as a ignition prevention unit mounted on a connection node to prevent the voltage transfer unit from operating in the normal mode due to a malfunction of the voltage transfer control unit.

Description

Ignition-proof auxiliary voltage output circuit

1 is a circuit diagram showing a power supply unit including a conventional auxiliary voltage output circuit.

2 is a circuit diagram showing a power supply unit including an auxiliary voltage output circuit according to the present invention.

* Explanation of symbols for main parts of the drawings

10: external power input unit 20: primary winding unit

30: power stabilization part 40: secondary main winding part

50: voltage adjusting unit 60: secondary auxiliary winding unit

70: voltage transfer unit 80: voltage transfer control unit

90: comparison stage 100: fire prevention unit

200A, 200B: Auxiliary Voltage Output Circuit

The present invention relates to an auxiliary voltage output circuit for supplying stable power to an internal circuit of an electronic device in a power saving mode. In particular, an auxiliary voltage is changed by changing a potential of another internal power supply voltage as a maximum voltage of the internal power supply voltage changes. The present invention relates to an auxiliary voltage output circuit including an ignition prevention unit for preventing an internal circuit from being ignited by malfunctioning an output circuit.

In general, the electronic device converts an AC power supplied from the outside into a DC voltage inside the device and supplies the same to an internal circuit, and uses an internal power source having various electric potentials according to the type of the device. It also drives internal circuits in mode.

Among them, a monitor, which is one of computer peripheral devices, is a representative example. Hereinafter, the monitor will be described as an example.

As computers become more popular, the necessity of computers is increasing in many fields, and the use of lightweight notebook PCs or laptop computers to handle tasks efficiently is increasing. The power consumed when performing a function and the power consumed by a portable computer are increasing due to the effect on the efficient use of the computer. In particular, power loss in a portable battery or a portable computer designed as a rechargeable battery has a tendency to be considered more important since it directly affects the use.

Therefore, even when the user does not use the computer for a certain period of time, information is displayed on the screen unnecessarily, and power consumption when an incomplete composite video signal enters the monitor due to unstable connection between the computer and the monitor. The current trend is to implement automatic power saving modes to reduce monitor power.

In order to realize the newly added power saving mode, the proper operation of the power supply circuit of the monitor is a display power management system (DPMS), and the power saving mode is used for the horizontal and vertical synchronization signals transmitted from the computer. It is divided into three modes depending on the presence or absence (the power consumption exemplified below is an example in which the monitor is 15 inches or less).

First, when the horizontal and vertical synchronization signals are normally transmitted, it is a normal mode, and all internal circuits necessary for displaying information on the screen operate normally, and power consumption of about 80 to 100W is generated.

Secondly, when neither the horizontal nor vertical synchronization signal is transmitted, it is an off mode. At this time, the monitor consumes minimum power (about 5 W).

Third, when only one of the horizontal and vertical synchronizing signals is transmitted, it is a suspend mode, which requires slightly higher power (about 15 W) than the off mode to operate necessary circuits.

In the normal mode, that is, when both horizontal and vertical synchronization signals are input, the information is displayed on the screen. However, in the off mode or the suspend mode, the information is not displayed on the screen. There is no reason to amplify the color signal. Therefore, in such a case, under the control of the microprocessor, the driving power transmitted from the power supply circuit to the internal circuits involved in vertical and horizontal deflection is cut off or the voltage is lowered. By reducing the supply by about 10%, power is not properly supplied to the internal circuits.

However, even when the monitor is operating in the power saving mode, the heater, synchronous IC chip, microprocessor, etc. used to deflect the electron beam should operate normally. Therefore, the supplied power supply voltage maintains the same potential as in the normal mode. Should be maintained. To this end, a method of transferring the output of a power supply circuit that outputs a high potential to a power supply voltage terminal such as a heater, a synchronous IC chip, a microprocessor, or the like in a power saving mode such as an off mode or a suspend mode is used, or during normal operation. If the high potential drops to about 10% in the power saving mode by using an auxiliary voltage output circuit that continuously outputs a potential higher than 10 times higher than the power supply voltage required by the above part, it should operate normally even in the power saving mode. A method of driving the parts is used.

1 is a circuit diagram showing a conventional power supply unit including an auxiliary voltage output circuit which realizes the second method described above, wherein an external power input unit 10 for transferring an AC voltage transmitted from the outside of the monitor to the inside and the external The primary winding unit 20 for smoothing the external voltage transmitted through the power input unit 10 to the internal circuit and the primary winding unit 20 for stably outputting the power voltage supplied to the internal circuit. Power supply stabilization unit 30 for controlling the operation of the main body, the secondary main winding unit 40 for inducing the internal power supplied to the internal circuit, and the voltage output from the main winding unit 40 is required in the internal circuit A voltage adjusting unit 50 for outputting a power supply voltage Vn of a constant potential by adjusting to a voltage equal to and a power supply for supplying a stable voltage Vs to an internal power supply terminal in place of the power supply voltage Vn in the power saving mode. Auxiliary voltage output And including a (200A).

Referring to the operation of each part schematically, first, if the primary winding unit 20 delivers the external power applied through the external power input unit 10 to the secondary side under the control of the power stabilizer 30. The main winding unit 40 outputs a power supply voltage to be supplied to the internal circuit, and the power adjustment unit 50 receives the output voltage of the main winding unit 40 and supplies a power supply voltage Vn of a constant potential required by the internal circuit. After readjustment, it is transferred to the internal power voltage terminal. Simultaneously with the operation of the main winding unit 40, the auxiliary voltage output circuit 200A also operates to output a power supply voltage having a potential 10 times higher than the output voltage of the main winding unit 40. However, the high voltage output through the auxiliary voltage output circuit 200A is controlled to be transferred to the internal power supply voltage terminal only in the power saving mode.

The auxiliary voltage output circuit 200A, which delivers a stable voltage to an internal power supply voltage stage in a power saving mode, is further provided with a secondary auxiliary winding unit 60 for supplying a power supply voltage required in a power saving mode, and the secondary side auxiliary winding. The voltage transfer unit 70 transfers the voltage output from the winding unit 60 to the power saving mode power supply voltage terminal Vs, and the output of the auxiliary winding unit 60 is transferred to the power supply voltage terminal Vs only in the power saving mode. It may be divided into a voltage transfer controller 80 that controls the operation of the voltage transfer unit 70 so as to.

The secondary auxiliary winding unit 60 has the same structure as the secondary main winding unit 40, and includes a transformer coil L2 and a diode D2 connected forward from the transformer coil L2 to the node N1. And a capacitor C2 connected between the node N1 and the ground voltage terminal.

The voltage transfer part 70 includes a resistor R3 connected to the output node N1 of the auxiliary winding part 60, the other node N11 of the resistor R3, and the auxiliary voltage output circuit 200A. A transistor Q2 connected between an output terminal Vs and a base end connected to a node N14, a transistor connected between the node N1 and a node N13 and a base end connected to a node N12 ( Q1), a resistor R4 connected between the node N1 and the node N12, a resistor R5 connected between the node N13 and a node N14, and the node N14. Resistor R6 connected between and output terminal Vs, and transistor Q3 connected between node N12 and node N15 and having a base terminal connected to output node N2 of voltage transfer controller 80. ) And a zener diode ZD1 connected forward from the node N15 to the ground voltage terminal, wherein the voltage transfer control unit 80 has a voltage at the output terminal Vn of the voltage adjusting unit 50. (Dc) is composed of an input load stage (R1, R2) to properly drop the voltage when it is transmitted through (Dc) and a comparison stage 90, the operation is controlled in accordance with the potential of the voltage delivered from the input load stage (R1, R2) The node N2 to which the voltage transfer unit 70 and the voltage transfer control unit 80 are connected is connected to a fixed voltage terminal Vcc.

As the fixed voltage terminal Vcc, a power supply voltage terminal for driving the microprocessor of the monitor is commonly used, and the diode Dc has a high voltage output from the auxiliary winding unit 60 of the voltage adjusting unit 50. It prevents the transfer to the output terminal (Vn).

The operation of the auxiliary voltage output circuit 200A having the above structure is divided into the normal mode and the power saving mode as follows.

First, in the normal mode in which the monitor operates normally, the voltage Vn output from the voltage adjusting unit 50 maintains a constant potential, and thus, the comparison stage of the voltage transfer control unit 80 via the diode Dc is thus maintained. Since the voltage delivered to 90 is higher than the internal reference voltage of the comparison unit 90, the comparison unit 90 operates so that the output node N2 of the voltage transfer control unit 80 becomes low. When the node N2 has a low state, all of the transistors Q1, Q2, and Q3 constituting the voltage transfer unit 70 are turned off, and the high voltage output from the auxiliary winding unit 60 is applied to the auxiliary voltage output terminal ( Vs) is not delivered.

However, when the monitor operating in the normal mode is switched to the power saving mode, the voltage output from the main winding part 40 and the auxiliary winding part 60 drops by about 10% compared to the normal mode, so that the internal power voltage In order to keep the potential constant at all times, the output voltage of the auxiliary winding part 60 outputting a voltage 10 times higher than the voltage output from the main winding part 40 should be transferred to the internal power supply voltage stage. Since the output voltage of the unit 40 drops to about 10% in the normal mode in the power saving mode, the output Vn of the voltage adjusting unit 50 is also lowered, thereby lowering the voltage applied to the voltage transfer control unit 80. Therefore, the voltage transmitted to the comparison stage 90 becomes lower than the internal reference voltage, so that the comparison stage 90 no longer operates. Then, the potential of the node N2 is increased by the current applied from the fixed voltage terminal Vcc, so that the transistors Q3, Q1, and Q2 of the voltage transmission unit 70 are sequentially turned on so that the auxiliary winding unit ( The voltage output from the 60 is transferred to the output terminal Vs of the auxiliary voltage output circuit 200A.

Therefore, as a result, the output voltage Vs of the auxiliary voltage output circuit 200A is applied to the internal power supply voltage terminal instead of the output voltage Vn of the voltage adjusting unit 50.

When the monitor is switched from the power saving mode to the normal mode again, the potential delivered through the diode Dc is increased again to operate the comparison terminal 90 of the voltage transfer control unit 80, so that each transistor of the voltage transfer unit 70 is operated. It is turned off again so that the output voltage of the auxiliary winding unit 60 is no longer transmitted to the output terminal Vs of the auxiliary voltage output circuit 200A.

When the monitor continuously switches the mode, the above operation is repeatedly performed, and a constant voltage is always output to the internal power supply voltage terminal.

However, although not shown in FIG. 1, the output Vn of the voltage adjusting unit 50 is below the threshold value in the normal mode due to various problems occurring in the internal circuit to which the internal power voltage output from the power supply unit is applied. Since the comparison terminal 90 of the voltage transfer control unit 80 stops the operation, the potential of the node N2 increases so that the transistors Q1, Q2 and Q3 of the voltage transfer unit 70 are turned on. In the normal mode, since the output voltage of the auxiliary winding unit 60 having a potential 10 times higher than the output voltage of the main winding unit 40 passes through the voltage transfer unit 70, the voltage transfer unit 70. Each part of the unit does not withstand excessive voltage and is destroyed, causing a problem of ignition.

Therefore, in the present invention, even if the output voltage of the voltage adjusting unit drops below a threshold due to an error occurring in an internal circuit to which a power supply voltage is applied, an auxiliary voltage including an ignition prevention unit for preventing the potential of the output node of the voltage transfer control unit from increasing By implementing the output circuit, there is a purpose to solve the problems of the conventional auxiliary voltage output circuit.

In order to achieve the above object, in the present invention, an auxiliary winding unit for outputting an auxiliary voltage, a voltage transmission unit connected to the auxiliary winding unit and transferring an output voltage of the auxiliary winding unit to an output terminal in a power saving mode, and a main winding unit A voltage transfer controller which senses an output change and controls an operation of the voltage transfer unit; The auxiliary voltage output circuit includes a ignition prevention unit mounted on a node to which the voltage transfer unit and the voltage transfer control unit are connected to always connect the connection node to the ground voltage terminal in the normal mode.

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

FIG. 2 is a circuit diagram showing a power supply unit including an auxiliary voltage output circuit according to the present invention. As in FIG. 1, an external power input unit 10 for transferring an AC voltage transmitted from the outside of the monitor to the inside thereof; The primary winding unit 20 for smoothing the external voltage transmitted through the external power input unit 10 and transmitting the internal voltage to the internal circuit, and the primary winding unit for stably outputting the power voltage supplied to the internal circuit. The power supply stabilization unit 30 for controlling the operation of the operation 20, the secondary main winding unit 40 for inducing a power supply voltage supplied to the internal circuit, and the voltage output from the main winding unit 40 to the internal circuit It is provided with a voltage adjusting unit 50 for outputting the power supply voltage (Vn) of a constant potential by adjusting to the voltage required by the, and in the power saving mode, a stable voltage at the internal power supply voltage terminal in place of the power supply voltage (Vn) Delivering The auxiliary voltage output circuit 200B of the present invention realizes stable operation even in a normal mode in which an abnormal operation in which the output voltage of the voltage adjusting unit 50 drops below a threshold occurs.

The auxiliary voltage output circuit 200B according to the present invention includes a secondary side auxiliary winding unit 60, a voltage transfer unit 70, a voltage transfer control unit 80, and the voltage transfer unit 70 having the same structure as that of FIG. 1. And the voltage transfer control unit 80 is composed of a ignition prevention unit 100 mounted to the node to which the connection is made.

Since the configuration and operation of the auxiliary winding unit 60, the voltage transfer unit 70 and the voltage transfer control unit 80 are the same as those described with reference to FIG. 1, further descriptions thereof will be omitted. Only the configuration and operation of 100 will be described.

In the newly added ignition preventing unit 100 according to the present invention, the voltage applied to the voltage transfer control unit 80 in the normal mode is lowered below the threshold value, so that the potential of the output node N2 cannot maintain the lowest state. It is to prevent the ignition phenomenon caused by being raised to the potential to operate the voltage transfer unit 70, the transistor (Q4) connected between the node (N2) and the ground voltage terminal, and the base of the transistor (Q4) The operation of the transistor Q4 is controlled by the power saving mode signal SUSb, which is composed of the input load stages R7 and R8 connected to the stage.

Therefore, since the power saving mode signal SUSb is applied in the high state during the normal mode operation, the transistor Q4 is turned on to always maintain the node N2 at the lowest state, and is applied in the low state during the power saving mode. The transistor Q4 is turned off by the power saving mode signal SUSb so that the potential of the node N2 is increased by the fixed voltage terminal Vcc as described in FIG.

As described above, when the auxiliary voltage output circuit according to the present invention described with reference to FIG. 2 is mounted on a power supply unit of an electronic device such as a monitor which executes a power saving mode operation, the internal circuit always performs a constant operation regardless of mode switching. Not only can the power supply voltage of the same potential be supplied, but also the abnormal operation of the internal circuit in the normal mode lowers the main power supply voltage below the threshold, thereby preventing the auxiliary voltage output circuit from being ignited by the operation of the ignition prevention section. Can be.

Claims (6)

A main voltage output circuit for supplying a voltage to the internal power supply voltage terminal in the normal mode, and an auxiliary voltage output circuit for supplying a voltage to the internal power supply voltage terminal in the power saving mode, and an auxiliary voltage at the output terminal of the main voltage output circuit. A power supply unit comprising a diode component forward connected to an output terminal of an output circuit, the power supply unit comprising: an auxiliary winding portion for outputting a voltage 10 times higher than the winding portion of the main voltage output circuit; and an output of the auxiliary winding portion in a power saving mode. A voltage transfer unit for supplying a voltage to an output terminal, a voltage transfer control unit configured to sense a voltage change of the output terminal to control an operation of the voltage transfer unit, and a connection node of the voltage transfer unit and the voltage transfer control unit to be mounted on the voltage transfer control unit. Comprising a ignition prevention portion for preventing the voltage transfer portion from operating in the normal mode due to malfunction of the Auxiliary voltage output circuit, characterized in that. 2. The auxiliary winding unit of claim 1, wherein the auxiliary winding unit comprises: a transformer coil for generating an induced voltage when a transformer operation is performed, a diode component forwardly connected from the transformer coil to an output terminal, and a capacitor component connected between the output terminal and the ground voltage terminal. Auxiliary voltage output circuit comprising a. The first node of claim 1, wherein the voltage transfer unit is connected between a first resistor connected to an output node of the auxiliary winding unit, the other node of the first resistor, and an output terminal of the auxiliary voltage output circuit. A first transistor connected to the first transistor, a second transistor connected between an output node of the auxiliary winding part and a second node, and having a base end connected to a third node, and connected between an output node of the auxiliary winding part and the third node. Connected second resistor, a third resistor connected between the second node and the first node, a fourth resistor connected between the first node and the output terminal, and connected between the third node and the fourth node. And a third transistor connected at a base end to an output node of the voltage transfer controller, and a zener diode connected to the ground voltage terminal at the fourth node in a forward direction. 4. The auxiliary voltage output circuit according to claim 3, wherein the first and third transistors have opposite operating characteristics from the second transistor. The method of claim 1, wherein the voltage transfer controller determines whether to operate by comparing an input load stage for appropriately lowering the output voltage of the main voltage output circuit delivered to the input stage with a voltage transmitted from the input load stage and an internal reference voltage. An auxiliary voltage output circuit comprising a comparison stage. The base circuit of claim 1, wherein the ignition prevention unit is configured to connect a transistor connected between a connection node of the voltage transfer unit, a voltage transfer control unit, and a ground voltage terminal, and a power saving mode signal applied to the base terminal of the transistor. An auxiliary voltage output circuit comprising an input load stage for transmitting to the stage.