KR100735498B1 - Power supply composing over voltage protection circuit - Google Patents

Abstract

A power supply apparatus having an over-voltage protection circuit is provided to prevent an over-voltage by controlling a controller of a power factor correction unit and to prevent a short circuit of an element by determining whether an over-voltage occurs based on an output voltage divided by a voltage division unit. A power supply apparatus having an over-voltage protection circuit includes a rectifying unit(220), a PFC(Power Factor Correction) unit(230), and an over-voltage protection circuit(240). The rectifying unit(220) receives an AC voltage from the outside and rectifies the received AC voltage to an input voltage of a DC component. The PFC unit(230) has a controller, a switch transistor, and input/output voltage division units. The PFC unit(230) is connected to the rectifying unit(220) and boosts up the input voltage applied from the rectifying unit(220). The over-voltage protection circuit(240) is connected to the PFC unit(230), and protects a circuit by breaking an over-voltage when the over-voltage occurs in an output voltage outputted from the PFC unit(230). An over-voltage determination unit(241) is connected to the output voltage division unit of the PFC unit(230), and receives the output voltage divided by the output voltage division unit. The over-voltage determination unit(241) determines whether the over-voltage occurs in the output voltage. A control unit(242) is connected to the over-voltage determination unit(241), and controls a controller of the PFC unit(230) by a signal which is applied from the over-voltage determination unit(241).

Description

Power supply with overvoltage protection circuit {Power Supply composing Over Voltage Protection Circuit}

1 is a circuit diagram of a power supply having a conventional overvoltage protection circuit.

2 is a circuit diagram of a power supply having an overvoltage protection circuit according to a first embodiment of the present invention.

3 is a circuit diagram of a power supply having an overvoltage protection circuit according to a second embodiment of the present invention.

4 is a circuit diagram of a power supply device having an overvoltage protection circuit according to a third embodiment of the present invention.

5 is a graph showing a change in output voltage of a power supply having an overvoltage protection circuit of FIG.

<Description of Symbols for Major Parts of Drawings>

210: power supply 220: rectifier

230: PFC stage 231: controller

232: input voltage divider 233: output voltage divider

240: overvoltage protection circuit 241: overvoltage determination unit

242 control unit 243 comparator

The present invention relates to a power supply having an overvoltage protection circuit, and more particularly, to a power supply for preventing an overvoltage generated in the power supply by adding an overvoltage protection circuit.

In general, a power supply device is a device for rectifying and supplying an AC power of a DC component to a DC power of a DC component in order to supply DC power of a DC component to be used in the devices connected thereto, for example, a motor, a computer, a TV, and the like. .

Recently, with the rapid development of electronic technology centering on computers, products with high controllability of small size and low power consumption have been developed, and the spread of a power supply device for safely supplying power to home appliances has been spreading.

Therefore, research is being actively conducted on a method of stably supplying a DC power of a DC component to drive an electronic circuit in a product using a power supply device.

Next, a power supply device having a conventional overvoltage protection circuit will be described in detail with reference to the related drawings.

1 is a circuit diagram of a power supply device having a conventional overvoltage protection circuit.

First, as shown in FIG. 1, the power supply device 100 including the conventional overvoltage protection circuit includes a rectifier 120, a PFC stage (Power Factor Correction 130), an output capacitor (Cout), and an overvoltage protection circuit. 140.

The rectifier 120 includes four rectifier diodes, and rectifies and outputs an AC input voltage vin of an AC component applied from the outside through the power supply unit 110 to an input voltage Vin of a DC component.

The PFC stage 130 includes an inductor L, first and second diodes D1 and D2, a controller 131, an input voltage divider 132, an output voltage divider 133, and a switch transistor SW. ) Is connected to the rectifier 120, improves the power factor by adjusting the waveform of the input voltage Vin, and boosts the input voltage Vin applied from the rectifier 120. Output a stable DC voltage.

Here, the first diode D1 is connected to the rectifier 120 to output an input voltage Vin applied from the rectifier 120, and the inductor L is connected to the rectifier 120. The input voltage Vin applied by the rectifier 120 is accumulated or output.

The output capacitor Cout is connected to the first and second diodes D1 and D2, and the input capacitor Cout is applied through the input voltage Vin and the second diode D2 applied through the first diode D1. The energy output from the inductor L is applied and accumulated.

The input voltage divider 132 includes a plurality of resistors and diodes, is connected to the rectifier 120, and distributes an input voltage Vin applied from the rectifier 120.

The output voltage divider 133 is composed of a plurality of resistors, is connected to the output capacitor Cout, and distributes the output voltage Vout output through the output node n1.

The controller 131 is connected to the input voltage divider 132, the output voltage divider 133, and the switch transistor SW, and input voltage Vin distributed by the input voltage divider 132. When the output voltage Vout distributed by the output voltage divider 133 is applied, the switch transistor SW is turned on when the input voltage Vin and the output voltage Vout are higher than or equal to a preset reference voltage. The magnitude of the output voltage Vout is maintained at the reference voltage.

The overvoltage protection circuit 140 includes first, second and third rated diodes ZD1, ZD2, ZD3, and ZD4, and is connected to the second diode D2 and the output capacitor Cout. When overvoltage occurs in the output voltage Vout, the first, second and third rated diodes ZD1, ZD2, ZD3, and ZD4 are shorted to ground the overvoltage.

Hereinafter, the operation of the power supply device 100 having the conventional overvoltage protection circuit of FIG. 1 will be described.

The rectifier 120 receives the AC input voltage vin of the AC component applied from the outside through the power supply 110 and rectifies the DC voltage to the input voltage Vin of the DC component.

Then, the switch transistor SW of the PFC stage 130 is turned on when the initial input voltage Vin is applied to accumulate energy in the inductor L, and is turned off when energy is accumulated in the inductor L. The energy accumulated in the inductor L is accumulated in the output capacitor Cout through the second diode D2. At this time, the output capacitor Cout boosts and outputs the input voltage Vin by storing an input voltage Vin applied through the first diode D1 and energy applied through the inductor L. .

In addition, the input voltage divider 132 distributes the input voltage Vin and applies the divided voltage to the input voltage detection terminal Vins of the controller 131 to divide the input voltage higher than a preset voltage. When applied, the switch transistor SW is turned on to prevent the output voltage Vout from rising above a certain voltage.

In addition, the output voltage distribution unit 133 distributes the output voltage Vout and applies the divided voltage to the output voltage detection terminal Vsense of the controller 131 to divide the voltage higher than a preset voltage. When applied, the switch transistor SW is turned on to prevent the output voltage Vout from rising above a predetermined voltage.

If an overvoltage is generated in the output voltage Vout, the output capacitor Cout is shorted by the overvoltage and the shorted output capacitor Cout generates heat, causing the power supply device 100 to malfunction. .

In order to prevent the malfunction, the first, second and third rated diodes ZD1, ZD2, and ZD3 of the overvoltage protection circuit 140 are short-circuited when an overvoltage of a predetermined voltage or more occurs, thereby causing the overvoltage generated. By grounding it, it is possible to prevent the malfunction of the power supply device 100 due to the overvoltage.

However, when the first, second and third rated diodes ZD1, ZD2, and ZD3 are short-circuited by an overvoltage, reuse of the first, second, and third rated diodes ZD1, ZD2, and ZD3 is not possible.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to configure the conventional overvoltage protection circuit as an overvoltage determiner and a controller to control the operation of the controller when overvoltage occurs in the output voltage. It is to provide a power supply with an overvoltage protection circuit that blocks overvoltage and can be used continuously without replacing a new device.

According to an aspect of the present invention, there is provided a power supply device including an overvoltage protection circuit, the rectifying unit configured to receive an AC voltage from the outside and rectify the input voltage to a DC component; A PFC stage including a controller, a switch transistor, an input and an output voltage divider, connected to the rectifier, and boosting an input voltage applied from the rectifier; And an overvoltage protection circuit connected to the PFC stage and protecting the circuit by blocking the overvoltage when an overvoltage is generated in the output voltage output from the PFC stage, wherein the overvoltage protection circuit includes an output voltage of the PFC stage. An overvoltage determination unit connected to the distribution unit and receiving an output voltage distributed by the output voltage distribution unit to determine whether an overvoltage is generated in the output voltage; And a control unit connected to the overvoltage determination unit and controlling the controller of the PFC stage by a signal applied from the overvoltage determination unit.

In addition, in the power supply device having an overvoltage protection circuit according to the present invention, the overvoltage determination unit is applied to the non-inverting signal input terminal the output voltage distributed by the voltage distribution unit, and distributes the drive power of the controller The comparator is applied to the inverted signal input terminal.

In addition, in the power supply having an overvoltage protection circuit according to the present invention, the overvoltage determiner outputs a high level signal when the voltage applied to the non-inverting signal input terminal is greater than the voltage applied to the inverting signal input terminal. It is done.

In addition, in the power supply having an overvoltage protection circuit according to the present invention, the overvoltage determination unit, a first resistor connected to the voltage divider of the PFC stage; A diode having an anode connected to the first resistor; And a first rated diode having a cathode connected to the cathode of the diode and an anode connected to the control unit.

In addition, in the power supply having an overvoltage protection circuit according to the present invention, the overvoltage determiner, when the overvoltage occurs in the output voltage is characterized in that for outputting a predetermined signal by conducting the first rated diode. .

In addition, the power supply device having an overvoltage protection circuit according to the present invention, the control unit includes: a first transistor connected to the overvoltage determiner and the collector, the base and the emitter in parallel with the first resistor and the first capacitor; A second resistor connecting the emitter of the first transistor and a driving power supply of the controller; A second transistor connected with a base of the first transistor, a collector of the first transistor connected with a base, and an emitter connected with a ground terminal; And a third resistor and a second capacitor connected in parallel with the base and the ground terminal of the second transistor.

In addition, in the power supply having an overvoltage protection circuit according to the present invention, the control unit is characterized in that for controlling the controller by turning on the second transistor by a predetermined signal applied from the overvoltage determination unit.

Further, in the power supply having an overvoltage protection circuit according to the present invention, the overvoltage determiner, the fifth resistor and the cathode connected to the output voltage divider of the PFC stage is connected to the second rated diode connected to the fifth resistor. Characterized in that made.

In addition, in the power supply having an overvoltage protection circuit according to the present invention, the overvoltage determiner further comprises a third capacitor, one end of which is connected to an anode of the second rated diode and the other end of which is connected to a ground terminal. It is done.

In addition, in the power supply having an overvoltage protection circuit according to the present invention, the overvoltage determiner is characterized in that when the overvoltage occurs in the output voltage, the second rated diode conducts and outputs a predetermined signal.

In addition, in the power supply having an overvoltage protection circuit according to the invention, the control unit, the gate is connected to the anode of the second rated diode, the anode is connected to the input voltage sensing terminal of the controller of the PFC stage The cathode may include a switching diode connected to a ground terminal.

In addition, in the power supply having an overvoltage protection circuit according to the invention, the control unit is characterized in that for controlling the controller by turning on the switching diode by a predetermined signal applied from the overvoltage determination unit.

Then, the related drawings will be described in detail with reference to the power supply device having an overvoltage protection circuit according to the present invention.

Example 1

2 is a circuit diagram of a power supply having an overvoltage protection circuit according to a first embodiment of the present invention.

First, as shown in FIG. 2, the power supply device 200 including the overvoltage protection circuit according to the first embodiment of the present invention includes a rectifier 220, a PFC stage 230, an output capacitor Cout, and the like. And an overvoltage protection circuit 240.

The rectifier 220 is composed of four rectifier diodes, connected to the PFC stage 230, the AC input voltage (vin) of the AC component applied from the outside through the power supply unit 210 of the DC component It rectifies with the input voltage Vin and outputs it.

The PFC stage 230 includes an inductor L, first and second diodes D1 and D2, a controller 231, an input voltage divider 232, an output voltage divider 233, and a switch controller SW. It is configured to be connected to the rectifier 220, improve the power factor by adjusting the waveform of the input voltage (Vin), boost the input voltage (Vin) to increase the output voltage (Vout) of a stable DC component Output

Here, the first diode D1 is connected to the rectifier 220 to output an input voltage Vin applied from the rectifier 220, and the inductor L is connected to the rectifier 220. The input voltage Vin applied by the rectifier 220 is accumulated or output.

The input voltage divider 232 includes a diode and a plurality of resistors, is connected to the rectifier 220 and the controller 231, and distributes an input voltage Vin applied from the rectifier 220 to the controller. To 231.

The output voltage divider 233 includes a plurality of resistors, is connected to the output capacitor Cout and the controller 231, and distributes the output voltage Vout to the controller 231.

The controller 231 is connected to the input voltage divider 232, the output voltage divider 233, and the switch transistor SW, and the input voltage Vin distributed by the input voltage divider 232 is An input voltage sensing terminal Vins is applied, and an output voltage Vout distributed by the output voltage distribution unit 233 is applied to an output voltage sensing terminal Vsense, and the divided input / output voltage is set in advance. When the reference voltage is higher than or equal to, the switch transistor SW is turned on.

The switch transistor SW is connected to the inductor L and the controller 231, and is turned on or off by the controller 231 to block a voltage output from the inductor L or the output capacitor. Apply to (Cout).

The overvoltage protection circuit 240 includes an overvoltage determiner 241 and a controller 242, and is connected to the controller 231 and the output voltage divider 233 of the PFC stage 230, and the output voltage. When overvoltage occurs in Vout, the controller 231 is controlled to protect the power supply device 200 by turning on the switch transistor SW.

The overvoltage determiner 241 includes first to third resistors R1, R2, and R3, a first capacitor C1, and a comparator 243, and is connected to the output voltage divider 233. The output voltage Vout distributed by the output voltage divider 233 is applied to the non-inverting signal input terminal (+) of the comparator 243, and the driving power supply Vcc of the PFC terminal 231 is It is distributed through the first to third resistors R1, R2, and R3 and applied to the inverting signal input terminal (-).

At this time, when the output voltage Vout applied to the non-inverting signal input terminal (+) of the comparator 243 is greater than the driving voltage applied to the inverting signal input terminal (-), an overvoltage is generated in the output voltage Vout. The control unit 242 outputs a high level signal to the controller 242 through the third diode D3.

The controller 242 of the overvoltage protection circuit 240 includes first and second transistors Q1 and Q2, fourth through sixth resistors R4, R5, and R6, and second and third capacitors C2 and C3. And a low level signal from the overvoltage determiner 241 through the third diode D3 and the third diode D3 and the controller 231. When the two transistors Q1 and Q2 are turned off to apply the driving power supply Vcc to the controller 231, and a high level signal is applied from the overvoltage determiner 241, the first transistor Q1 is applied. Is turned on to stop the operation of the controller 231 by grounding the driving power source Vcc applied to the controller 231.

In this case, the first transistor Q1 is connected to one end of a fifth resistor R5 and a second capacitor C2 having emitters connected in parallel, and a base is connected to the fifth resistor R5 and the second capacitor C2. And the collector is connected to the overvoltage determiner 241.

In addition, the second transistor Q2 has an emitter connected to a ground terminal, a base connected to a collector of the first transistor Q1, and a collector connected to a base of the first transistor Q1.

In addition, the controller 242 may include a fourth resistor R4 and a base of the second transistor Q2 connecting the emitter of the first transistor Q1 and the driving power supply Vcc of the controller 231. And a sixth resistor and a third capacitor C3 connected in parallel between the ground terminal and the ground terminal.

Next, the operation of the power supply device 200 including the overvoltage protection circuit according to the present invention will be described in detail.

The rectifier 220 receives an AC input voltage vin of an AC component applied from the outside through the power supply 210 and rectifies the input voltage Vin of the DC component to the PFC terminal 230.

The PFC stage 230 accumulates the input voltage Vin applied from the rectifier 210 in the output capacitor Cout through the first diode D1 and stores the voltage accumulated in the inductor L. By accumulating in the output capacitor Cout through the two diodes D2, the input voltage Vin is boosted to output the output voltage Vout.

In this case, the controller 231 receives an input voltage Vin distributed through the input voltage divider 232 as an input voltage sensing terminal Vin, and the divided voltage is higher than a preset voltage. By turning on the switch transistor SW to ground the voltage output through the inductor L, the output voltage Vout is controlled to be maintained at a constant voltage.

In addition, the controller 231 receives the output voltage Vout distributed through the output voltage divider 233 as an output voltage sensing terminal Vsense, and the divided output voltage Vout is set in advance. When the voltage is higher than the voltage, the switch transistor SW is turned on to ground the voltage output through the inductor L, thereby controlling the output voltage Vout to be maintained at a constant voltage.

If an overvoltage occurs in the output voltage Vout, the voltage applied to the non-inverting signal input terminal (+) of the comparator 243 is greater than the divided voltage applied to the inverting signal input terminal (-). The comparator 243 outputs a high level signal.

Then, the second transistor Q2 of the controller 242 is turned on by receiving the high level signal through the third diode D3 to ground the driving power Vcc applied to the controller 231. Let's do it.

As a result, the controller 231 does not receive the driving power supply Vcc and stops its operation. Accordingly, the switch transistor SW is turned on to ground the voltage output from the inductor L.

When the overvoltage is generated as described above, the overvoltage protection circuit 240 cuts the driving power Vcc of the controller 231 to turn on the switch transistor SW, thereby outputting the output voltage Vout by the overvoltage. ) To prevent it from rising.

If the overvoltage is not generated and the output voltage Vout in the steady state is output, the comparator 243 of the overvoltage determiner 241 outputs a low level signal, and at this time, the second transistor of the controller 242. Since Q2 is turned off, the controller 231 receives the driving power Vcc, and accordingly, the power supply device 200 operates normally.

Next, a second embodiment of the present invention will be described in more detail with reference to FIG. 3. However, the description of the same parts as those of the first embodiment of the configuration of the second embodiment will be omitted, and only the configuration that is different from the second embodiment will be described in detail.

Example 2

3 is a circuit diagram of a power supply device having an overvoltage protection circuit according to a second embodiment of the present invention.

As shown in FIG. 3, the power supply device 300 including the overvoltage protection circuit according to the second embodiment of the present invention is largely divided into a rectifier 320, a PFC stage 330, and an overvoltage protection circuit 340. It is composed.

The overvoltage protection circuit 340 includes an overvoltage determiner 341 and a controller 342, is connected to the controller 331 and the output voltage divider 333, and an overvoltage is generated in the output voltage Vout. If so, the drive power (Vcc) of the controller 331 is cut off.

The overvoltage determiner 341 may include a first resistor R1 connected to the output voltage divider 333, a third diode D3 connected to an anode of the first resistor R1, and a cathode connected to the third resistor D1. It consists of a rated diode (ZD1) connected to the cathode of the diode (D3).

In addition, the control unit 342 of the overvoltage protection circuit 340 has the same structure as the control unit (see reference numeral 242 in FIG. 2) of the first embodiment described above.

Hereinafter, the operation of the power supply device 300 including the overvoltage protection circuit according to the second embodiment of the present invention will be described in detail.

When overvoltage occurs in the output voltage Vout, the output voltage Vout distributed by the output voltage divider 333 is applied through the first resistor R1, and the rated diode ZD1 is It is conducted by the output voltage Vout applied through the first resistor R1 and the third diode D3.

The second transistor Q2 is turned on by the output voltage Vout applied through the rated diode ZD1 to ground the driving power supply Vcc applied to the controller 331.

As a result, the controller 331 does not receive the driving power supply Vcc and stops its operation. Accordingly, the switch transistor SW is turned on to ground the voltage output from the inductor L, thereby outputting the output. The increase of the voltage Vout is blocked.

If the overvoltage is not generated and the output voltage Vout in the steady state is applied, the rated diode ZD1 is cut off and the second transistor Q2 is turned off. By operating under the application of Vcc), the power supply device 300 operates normally.

Next, a third embodiment of the present invention will be described in more detail with reference to FIGS. 4 and 5. However, the description of the same parts as those of the first and second embodiments of the configuration of the third embodiment will be omitted, and only the configuration different from the third embodiment will be described in detail.

Example 3

FIG. 4 is a circuit diagram of a power supply device having an overvoltage protection circuit according to a third embodiment of the present invention, and FIG. 5 shows a change in output voltage Vout of the power supply device having an overvoltage protection circuit of FIG. It is a graph.

As shown in FIG. 4, the overvoltage protection circuit 300 according to the third embodiment of the present invention includes a rectifier 420, a PFC stage 430, and an overvoltage protection circuit 440.

The overvoltage protection circuit 440 includes an overvoltage determiner 441 and a controller 442, is connected to the controller 431 and the output voltage divider 433, and an overvoltage is applied to the output voltage Vout. When generated, the driving power source Vcc of the controller 331 is cut off.

The overvoltage determiner 441 includes a first resistor R1 connected to the output voltage divider 443, a cathode of the rated diode ZD1 connected to the first resistor R1, and an anode of the rated diode ZD1. And a capacitor C1 connected to the controller 431. The capacitor C1 is connected to the controller 431 and the output voltage distribution unit 443. When the overvoltage occurs in the output voltage Vout, the rated diode ZD1 is conducted.

In addition, the control unit 442, the gate is connected to the contact of the rated diode (ZD1) and the capacitor (C4), the anode of the input voltage sensing terminal (Vins) and the input voltage distribution unit 432 of the controller 431. A switching diode ZD2 connected to a contact point of the cathode and a cathode connected to the ground terminal, connected to the controller 431 and the input voltage divider 432, and applied by a signal applied from the overvoltage determiner 441. It is connected to the input voltage sensing terminal (Vins) of the controller 431 is applied to ground the input voltage (Vin) applied.

As described above, the power supply device 400 of the third embodiment is configured to supply power by configuring the overvoltage protection circuit 440 only with the first resistor R1, the rated diode ZD1, the capacitor C1, and the switching diode ZD2. This has the advantage of reducing the size of the device 400.

Hereinafter, the operation of the power supply device 400 including the overvoltage protection circuit according to the present invention will be described in detail.

If overvoltage occurs in the output voltage Vout, the rated diode ZD1 is conducted by the output voltage Vout applied through the first resistor R1.

The switching diode ZD2 is turned on by the conductive rated diode ZD1, and thus the output voltage Vout applied to the input voltage sensing terminal Vins of the controller 431 is grounded.

Therefore, the controller 431 determines that an overvoltage has occurred and applies a turn on signal to the switch transistor SW. The switch transistor SW turned on by the signal cuts off the output voltage Vout by grounding the voltage output from the inductor L.

If an overvoltage is not generated and a normal output voltage Vout is applied, the rated diode ZD1 is cut off and the switching diode ZD2 is also cut off by the blocked rated diode ZD1. The controller 431 is operated by receiving the divided input voltage Vin to operate the power supply 430 normally.

In addition, as shown in FIG. 5, when an overvoltage is generated at the time 'A' while the output voltage Vout of 380V is supplied to the power supply device 400 of FIG. 4, the overvoltage protection circuit 440. The rated diode ZD1 and the switching diode ZD2 are conducted so that the controller 431 turns on the switch transistor SW to be cut off at 488V. Although not shown, when compared to the conventional 744V up and off, it can be seen that the cut off at a significantly lower voltage, thereby protecting the power supply 400 more effectively.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, but various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also within the scope of the present invention.

As described above, the power supply device having the overvoltage protection circuit according to the present invention comprises the overvoltage protection circuit as an overvoltage determining unit and a control unit to prevent overvoltage by controlling the controller of the PFC stage when overvoltage occurs in the output voltage. It can work.

In addition, the power supply device, by using the output voltage distributed by the voltage divider and the over-voltage determination unit and the control unit to determine the occurrence of the overvoltage by preventing the short circuit of the device can be used continuously without replacement of a new device There is.

Claims (12)

Rectifying unit for receiving the AC voltage from the outside to rectify the input voltage of the DC component; A PFC stage including a controller, a switch transistor, an input and an output voltage divider, connected to the rectifier, and boosting an input voltage applied from the rectifier; And an overvoltage protection circuit connected to the PFC stage and protecting the circuit by blocking the overvoltage when an overvoltage is generated in an output voltage output from the PFC stage. The overvoltage protection circuit, An overvoltage determiner connected to the output voltage divider of the PFC stage and receiving an output voltage distributed by the output voltage divider to determine whether an overvoltage is generated in the output voltage; And A control unit connected to the overvoltage determination unit and controlling a controller of the PFC stage by a signal applied from the overvoltage determination unit; Power supply having an overvoltage protection circuit comprising a. The method of claim 1, The overvoltage determining unit is an overvoltage protection circuit, characterized in that the comparator receives the output voltage distributed by the output voltage divider to the non-inverting signal input terminal, distributes the driving power of the controller and is applied to the inverting signal input terminal. One power supply. The method of claim 2, And the overvoltage determiner outputs a high level signal when the voltage applied to the non-inverting signal input terminal is greater than the voltage applied to the inverting signal input terminal. The method of claim 1, The overvoltage determination unit, A first resistor connected to the voltage divider of the PFC stage; A diode having an anode connected to the first resistor; And And a cathode connected to the cathode of the diode, and an anode connected to the control unit, the first rated diode being connected to the cathode of the diode. The method of claim 4, wherein And the overvoltage determiner is configured to conduct the first rated diode and output a predetermined signal when an overvoltage occurs in the output voltage. The method according to claim 3 or 5, The control unit, A first transistor having an emitter connected to one end of a second resistor and a first capacitor connected in parallel, a base connected to the other end of the second resistor and a first capacitor, and a collector connected to the overvoltage determiner; A third resistor connecting the emitter of the first transistor and the driving power of the controller; A second transistor having an emitter connected to a ground terminal, a base connected to a collector of the first transistor, and a collector connected to a base of the first transistor; And And a fourth resistor and a second capacitor connected in parallel between the base and the ground terminal of the second transistor. The method of claim 6, And the control unit controls the controller by turning on the second transistor according to a signal applied from the overvoltage determining unit. The method of claim 1, The overvoltage determination unit, And a fifth resistor and a cathode connected to the output voltage divider of the PFC stage, and a second rated diode connected to the fifth resistor. The method of claim 8, And the overvoltage determiner further comprises a third capacitor connected to an anode of the second rated diode and the other end connected to a ground terminal. The method of claim 9, And the overvoltage determiner is configured to conduct the second rated diode and output a predetermined signal when an overvoltage occurs in the output voltage. The method of claim 10, The control unit, the overvoltage protection circuit characterized in that the gate is connected to the anode of the second rated diode, the anode is connected to the input voltage sensing terminal of the controller of the PFC stage, the cathode is made of a switching diode connected to the ground terminal. Power supply having a. The method of claim 11, And the control unit controls the controller by turning on the switching diode according to a predetermined signal applied from the overvoltage determining unit.

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