KR20170076266A - Protection Circuit for Power Supply - Google Patents

Abstract

The present invention relates to a surge protection circuit for a power supply device capable of effectively discharging an abnormal voltage exceeding a preset voltage level, including a surge voltage, through an AC power input terminal, thereby protecting a power source connected to a subsequent stage, An AC power input terminal; At least one filter unit electrically connected to a rear end of the AC power input terminal and suppressing noise introduced into the AC power input terminal; And a surge protector electrically connected to the AC power input terminal and the filter unit to discharge a voltage exceeding a preset voltage level including a surge, the filter unit comprising: a live input unit And a common mode choke (CMC) which is composed of a pair of inductors connected in series to a neutral input terminal and removes the same phase noise introduced into the AC power input terminal, And an arrestor (ARRESTER) connected in parallel to each inductor of the common mode choke (CMC).

Description

[0001] The present invention relates to a surge protection circuit for a power supply device,

The present invention relates to a surge protection circuit for a power supply device capable of effectively discharging an abnormal voltage exceeding a preset voltage level, including a surge voltage, through an AC power input terminal, thereby protecting a power source connected to a subsequent stage.

Recently, the installation of information communication devices including computers, central processing units (CPU) and microprocessors that are vulnerable to high voltage such as information, communication, signal and image systems has been rapidly increased due to high integration and automation of building and industrial facilities And the quality of the supplied power is very important.

Therefore, the social demand for the stable supply of electric power and the qualitative securing of the information communication network is increasing due to the advanced information system, the urban functionalization, and the high - tech use of the electric energy.

For example, there is a need for a power supply device that stably supplies input power required for operation of electric or electronic products such as LED lighting lamps, various display devices, and PCs installed indoors and outdoors.

The power supply unit adopted in the electric or electronic product converts AC power to suit the input power of the required equipment, and supplies the AC power to each circuit in the product. At this time, A surge voltage or a surge current may be inputted to cause serious damage such as breakage of the electronic parts inside the product, fatal damage of the electric and electronic equipment, malfunction of the program, and the like.

In order to solve the above problems, researches on a surge protection circuit for protecting an internal part, for example, a power supply device, by interrupting a surge input to the power supply device have been actively conducted.

Korean Patent Publication No. 10-2008-0013527 (Feb. 13, 2008)

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a surge protection circuit for a power supply device capable of effectively discharging an abnormal voltage exceeding a predetermined voltage level including a surge voltage through an AC power input terminal, .

According to an aspect of the present invention, there is provided a surge protection circuit for a power unit, the surge protection circuit comprising: an AC power input terminal; At least one filter unit electrically connected to a rear end of the AC power input terminal and suppressing noise introduced into the AC power input terminal; And a surge protector electrically connected to the AC power input terminal and the filter unit to discharge a voltage exceeding a preset voltage level including a surge, the filter unit comprising: a live input unit And a common mode choke (CMC) which is composed of a pair of inductors connected in series to a neutral input terminal and removes the same phase noise introduced into the AC power input terminal, And an arrestor (ARRESTER) connected in parallel to each inductor of the common mode choke (CMC).

As one example, the AC power input terminal is electrically connected between the live input terminal and the ground (FG) terminal and between the neutral input terminal and the ground (FG) terminal, And a first and a second bypass unit for bypassing an abnormal voltage exceeding the level to the ground (FG) terminal.

As an example, the first and second bypass units may be configured such that a varistor and an arrester are connected in series.

For example, the overcurrent protection unit may include at least one fuse connected in series to a live input terminal or a neutral input terminal of the AC power input terminal.

As an example, the surge protector may further include at least one varistor connected in parallel with the common mode choke (CMC) between a live input and a neutral input at the AC power input terminal .

As an example, the overcurrent protection unit may include first and second fuses connected in series to a live input terminal of the AC power input terminal, and a varistor of the surge protection unit may include a first fuse and a second fuse, As shown in FIG.

As one example, the filter unit may include first and second capacitors connected in parallel between a live input terminal and a neutral input terminal on a primary side and a secondary side, respectively, of the common mode choke (CMC) An X-cap for eliminating normal mode noise; And third and fourth capacitors connected in parallel between the live input terminal and the ground (FG) terminal and between the neutral input terminal and the ground (FG) terminal, and common mode noise cap (Y-cap) that removes common mode noise.

The surge protection circuit for a power supply device of the present invention is characterized in that an arrestor is connected in parallel to each inductor of a common mode choke (CMC) applied as a filter section.

Accordingly, when an abnormal voltage exceeding a predetermined voltage level including a surge voltage is input to the filter unit through the AC power input terminal, it is possible to effectively prevent the filter unit from being charged by the abnormal voltage, So that it is possible to protect not only the filter unit itself but also a circuit or a power supply unit connected to the rear end.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing the configuration of a surge protection circuit according to an embodiment of the present invention; Fig.
2 is a view showing a configuration of a filter unit according to an embodiment of the present invention;

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

FIG. 1 is a view illustrating a configuration of a surge protection circuit according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating a configuration of a filter unit according to an embodiment of the present invention.

As shown in FIG. 1, the surge protection circuit (hereinafter, referred to as 'protection circuit') of the present invention includes an AC power input terminal 100 for receiving an AC power, And a filter unit 200 connected to the AC power input terminal 100 and the filter unit 200. The filter unit 200 includes at least one filter unit 200 for suppressing noise introduced into the AC power input terminal 100, And a surge protection unit 300 for discharging the voltage. A power unit for receiving AC power output from the filter unit 200 and processing and outputting the AC power may be provided at a rear end thereof have.

The AC power input terminal 100 includes a live input terminal AC-L and a neutral input terminal AC-N for receiving AC power, and a configuration for preventing noise (FG).

The filter unit 200 includes a pair of inductors connected in series to each AC power input terminal 100, that is, a live input terminal AC-L and a neutral input terminal AC-N, And a common mode choke (CMC) for removing noise of the same phase drawn into the input terminal 100. The filter unit may be selectively provided at least one.

Here, the filter unit 200 may further include first to fourth capacitors C1 to C4 in addition to the common mode choke (CMC) in order to effectively remove noise from the input voltage.

More specifically, as shown in FIG. 2, the filter unit 200 includes first and second capacitors C1 and C2 on the primary side and the secondary side, respectively, of a common mode choke (CMC) The two capacitors C1 and C2 are formed of an X-cap.

In this case, the first and second capacitors C1 and C2 are all configured in the present invention. However, the present invention is not limited thereto, and the first and second capacitors C1 and C2 may be formed by only one capacitor, The primary side or the secondary side first capacitor C1 or the second capacitor C2 of the choke CMC may be constituted.

A third capacitor C1 is connected between the live input terminal AC-L and the ground terminal FG of the AC power input terminal 100 at the front end of the first capacitor C1 or at the rear end of the second capacitor C2. And a fourth capacitor C4 is formed between the neutral input terminal AC-N and the ground terminal FG of the AC power input terminal 100. [

At this time, the third and fourth capacitors C3 and C4 are formed of a Y-cap for connection with the ground terminal FG.

To simplify the filtering operation of the filter unit 200, the common mode choke (CMC) increases the impedance when a high frequency surge voltage is applied, while preventing the surge voltage from being transmitted to the rear end or the secondary side, (AC-L) and a neutral (AC-N) input terminal (AC-N) of the AC power input terminal 100 have a high impedance in a frequency range and have an excellent noise suppression function. When they come in, they cancel each other out.

The X-cap composed of the first and second capacitors C1 and C2 may be formed by a conductive noise such as a lightning surge, high frequency noise of other electric / electronic equipment, pulse noise, That is, normal mode noise, when it is introduced along the power supply line of the live input (AC-L) and the neutral (AC-N) do.

In the case of a Y-cap composed of the third and fourth capacitors C3 and C4, common mode noise such as high-frequency switching noise, which may occur when high-frequency switching is performed for converting from the power supply, mode noise to the outside.

There are usually two types of conduction modes, "Differential Mode" and "Common Mode", for conduction noise flowing through power lines and signal lines.

Differential mode noise, that is, normal mode noise refers to a noise transmitted through two stranded conductors, in which noises are present only in the V + line of a signal line or a power source. (Here, Direction are different from each other).

The common mode noise is a noise that is generated when noise of the same phase is induced between a reference point such as the ground FG and a ground.

As described above, in the case of the filter unit 200 according to the present embodiment, the first and second capacitors C1 and C2 are formed in X-cap in addition to the common mode choke CMC, (AC-L) and a neutral input terminal (AC-N) are provided in the AC power input terminal 100 by configuring the first and fourth capacitors C3 and C4 as Y- ), The common mode signal is canceled by attenuating the flow, the differential mode signal can pass the signal without attenuation, and the normal mode noise and the common mode noise can be eliminated .

As shown in FIG. 1, the protection circuit according to an embodiment of the present invention includes an overcurrent protection unit 400 configured to protect a circuit from an overcurrent at the front end of a surge protection unit 300, The first and second bypass units 500 and 510 for bypassing an abnormal voltage exceeding the ground voltage to the ground (FG) terminal.

The overcurrent protection unit 400 may include one or more fuses connected in series to the live input AC-L or the neutral input AC-N at the AC input. have.

The fuse is designed to be short-circuited by heat generation when an over-current exceeding a predetermined current level is inputted to the AC power input terminal 100, thereby protecting circuits and components connected to the subsequent stage from the overcurrent. The fuse is immediately reflected to the AC power input terminal 100 when an abnormal voltage or a current including a surge is inputted, thereby preventing an excessive current from flowing continuously.

The surge protector 300 is connected to the common mode choke CMC between the live input terminal AC-L and the neutral input terminal AC-N of the AC power input terminal 100, And at least one varistor connected in parallel with the output terminal.

The varistor clamps the overvoltage when an overvoltage exceeding a predetermined voltage level including a surge voltage due to lightning or opening and closing of a power system is drawn through both ends of the AC power input terminal 100.

Such a varistor may have a structure in which a pair of zener diodes having a function of a constant voltage diode are connected opposite to each other and the current-voltage characteristic of the varistor is substantially symmetrical in the forward and reverse directions and excellent current- Respectively.

In addition, the varistor is a characteristic in which the resistance value changes flexibly according to the input voltage. When the voltage input between both terminals, that is, the live input terminal and the neutral input terminal, is in a steady state below a predetermined voltage level, For example, a lightning surge or the like, an instantaneous surge-like abnormal voltage is applied. However, when the voltage applied across both ends exceeds a predetermined voltage level, So that the rising surge voltage is clamped to have a constant voltage level.

According to a preferred embodiment of the present invention, the overcurrent protection unit 400 includes a first and a second fuses (not shown) connected to a live input AC-L of the AC power input terminal 100, F1 and F2 are connected in series and the surge protection unit 300 shows an example where the first varistor VA1 is connected between the secondary side of the first fuse F1 and the primary side of the second fuse F2 So that the overcurrent cutoff and the clamping of the output voltage to the surge can be performed step by step.

The first bypass unit 500 is electrically connected between the live input terminal AC-L and the ground terminal FG at the AC power input terminal and includes a surge, When the voltage is pulled, it is bypassed to the ground (FG) terminal.

The second bypass unit 510 is electrically connected between the neutral input terminal AC-N and the ground terminal FG at the AC power input terminal. The second bypass unit 510 includes a surge, To the ground (FG) stage.

As shown in FIG. 1, the first and second bypass units 500 and 510 are configured such that a varistor VA and an arrestor AR are connected in series, An abnormal voltage may be induced to the first or second bypass unit 500 or 510 depending on the characteristic of the varistor when the voltage is inputted to a live input terminal or a neutral input terminal, By allowing the abnormal voltage to be bypassed to ground after discharging, the damage to the circuit connected to the subsequent stage is minimized.

The output voltage clamped according to the first varistor VA1 of the surge protection unit 300, that is, the rapidly changing high voltage, can be instantaneously charged between both ends of the filter unit 200. [ As described above, since the abnormal voltage charged in the filter unit 200 is not provided with a separate discharging means, the discharge can not be performed, the discharge is generated between the connection pins of the filter unit 200, and the abnormal discharge Not only the damage to the filter unit 200 itself but also the power unit at the rear end associated with the filter unit 200 may be affected, which results in various problems such as abnormal operation of the power supply unit and shortening of the life span.

1, the surge protector 300 of the present invention includes an arrestor electrically connected to the filter unit 200 to solve the above-mentioned problems, The filter unit 200 and the like to protect the power supply unit.

The arresters AR1 and AR2 of the surge protector 300 are connected in parallel to the respective inductors of the common mode choke CMC so as to be connected to the AC power input terminal 100 So that the discharge can be performed.

The arresters AR1 and AR2 maintain the state of the insulator at a predetermined voltage level, that is, below a predetermined discharge start voltage, and when the discharge start voltage is exceeded, they change into conductors to instantaneously perform a discharge operation, The abnormal voltage including the surge is prevented from being introduced into the unit 200 and the abnormal voltage is restored to a predetermined voltage or less.

Also, the arresters AR1 and AR2 can be shut off by the characteristic of returning to the insulator state immediately after the discharge is completed in order to prevent a ground fault that may occur after the discharge.

The power unit is electrically connected to a secondary side of the filter unit 200 and receives AC power that has passed through the filter unit 200. As described above, the power unit processes the input AC power, for example, by switching it by a PWM (Pulse Width Modulation) method and converts the DC power to a DC power suitable for the device to be powered.

As described above, the protection circuit according to the present invention is characterized in that the arrestors AR1 and AR2 are connected in parallel to the respective inductors of the common mode choke (CMC) applied to the filter unit 200, When an abnormal voltage exceeding a preset voltage level is drawn into the filter unit 200 through the AC power input terminal 100, the filter unit 200 is charged by the abnormal voltage that has not completely disappeared even with the conventional surge protection circuit So that it is possible to protect the filter unit 200 itself as well as a circuit or a power source unit connected to the rear end.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

100: AC power input terminal 200:
300: surge protection unit 400: overcurrent protection unit
500: first bypass unit 510: second bypass unit

Claims (7)

AC power input; At least one filter unit electrically connected to a rear end of the AC power input terminal and suppressing noise introduced into the AC power input terminal; And a surge protector electrically connected to the AC power input terminal and the filter unit for discharging a voltage exceeding a predetermined voltage level including a surge,
The filter unit includes:
And a common mode choke (CMC) which is composed of a pair of inductors connected in series to a live input terminal and a neutral input terminal and removes the same phase noise introduced into the AC power input terminal,
The surge protector includes:
And an arrester (ARRESTER) connected in parallel to each inductor of the common mode choke (CMC).
The method according to claim 1,
The AC power input terminal is electrically connected between the live input terminal and the ground (FG) terminal and between the neutral input terminal and the ground (FG) terminal. Further comprising a first and a second bypass for bypassing the voltage to the ground (FG) when the voltage is drawn.
3. The method of claim 2,
Wherein the first and second bypass units are arranged in a matrix,
Characterized in that the VARISTOR and the ARRESTER are connected in series.
The method of claim 3,
Further comprising an overcurrent protection unit formed of one or more fuses connected in series to a live input terminal or a neutral input terminal of the AC power input terminal.
5. The method of claim 4,
The surge protector includes:
Further comprising at least one varistor connected in parallel with the common mode choke (CMC) between a live input terminal and a neutral input terminal of the AC power input terminal, .
6. The method of claim 5,
The overcurrent protection unit includes:
The first and second fuses are serially connected to a live input terminal of the AC power input terminal,
And a varistor of the surge protection unit is connected between the first fuse and the second fuse.
The method according to claim 6,
The filter unit includes:
First and second capacitors are connected in parallel between a live input terminal and a neutral input terminal on the primary side and the secondary side of the common mode choke (CMC), respectively, to remove normal mode noise X-cap; And
The third and fourth capacitors are connected in parallel between the live input terminal and the ground (FG) terminal, between the neutral input terminal and the ground (FG) terminal, and common mode noise common to the switching noise, (Y-cap) that removes power supply noise and mode noise of the surge protection circuit.

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