Abnormal signal blocking device and power conversion device

Abstract

An abnormal signal blocking device disclosed herein may include: a voltage sensing circuit that is connected to a first power line, a second power line, and a first node and senses an input side voltage between the first power line and the second power line; a constant current source connected to the first node; and a detection circuit that is connected to the first node and detects an abnormal signal on the basis of the voltage of the first node, wherein the voltage of the first node changes according to the sensed input side voltage. The constant current source can supply a current mirror to the first node so that the voltage of the first node changes according to the sensed input side voltage.

Description

Abnormal signal blocking device and power conversion device

[0001] The embodiment relates to an abnormal signal blocking device and a power conversion device.

[0002] Power conversion devices are widely used in most industries. Power conversion devices use multiple switching elements to convert and output power.

[0003] Power conversion devices are exposed to external environments, subject to abnormal signals, such as surge voltages ranging from thousands to tens of thousands of volts. Failure to proactively block these surge voltages can damage circuit components, such as switching elements, leading to malfunctions, failures, or even breakdowns in electronic devices containing the power conversion device.

[0004] Conventional techniques have been proposed to block surge voltages by detecting current through a current sensing unit installed on one side of a switching element. However, conventional techniques detect avalanche currents flowing due to the breakdown voltage of the switching element caused by the surge voltage. Consequently, there is a risk of damage to the switching element, the driving unit, or the circuit components connected to the switching element due to the avalanche current.

[0005] The present invention aims to solve the above-mentioned and other problems.

[0006] Another object of the present invention is to provide an abnormal signal blocking device and a power conversion device capable of improving product reliability by blocking abnormal signals in advance.

[0007] The technical problems of the embodiment are not limited to those described in this article, but include those that can be understood through the description of the invention.

[0008] According to one aspect of the embodiment to achieve the above or other purposes, the abnormal signal blocking device includes: a voltage detection circuit connected to a first power line, a second power line, and a first node, and detecting an input-side voltage between the first power line and the second power line; a constant current source connected to the first node; and a detection circuit connected to the first node, and detecting an abnormal signal based on a voltage of the first node that varies according to the detected input-side voltage; wherein the constant current source supplies a current mirror to the first node so that the voltage of the first node varies according to the detected input-side voltage.

[0009] The above detection circuit may include a comparator.

[0010] The abnormal signal blocking device may further include a driving unit that outputs a switching signal to drive a first switching element and a second switching element. The first switching element and the second switching element are connected in series between the first power line and the second power line, and the driving unit may drive the first switching element and the second switching element based on the detected abnormal signal.

[0011] The above driving unit can, during normal operation, turn on one of the first switching element and the second switching element and turn off the other switching element according to the switching signal. The detection circuit can, when the voltage of the first node is equal to or higher than the first set value, transmit the abnormal signal to the driving unit, and the driving unit can turn off the switched-on switching element according to the transmitted abnormal signal.

[0012] The above detection circuit transmits a maintenance signal to the driving unit when the voltage of the first node is less than the first set value, and the driving unit can maintain the turned-off switching element based on the transmitted maintenance signal.

[0013] The driving unit can turn on the switching element that maintains the off state based on the second set value set by using the hysteresis characteristics of each of the first switching element and the second switching element.

[0014] The above abnormal signal blocking device may include a constant voltage source connected to the driving unit and obtaining the first set value.

[0015] The above constant current source can be connected to the driving unit to receive power voltage.

[0016] The voltage sensing circuit may include a first impedance element between the first power line and the second node; a second impedance element between the second node and the second power line; and a protection element between the first node and the second node.

[0017] The above protection element may include a reverse voltage prevention element connected to the second node.

[0018] The above protection element may further include a voltage sensing element connected to the reverse voltage prevention element.

[0019] The above protection element may further include a DC voltage blocking element connected between the voltage sensing element and the first node.

[0020] The above protection element may further include a frequency filter element connected in parallel with the voltage sensing element at the first node.

[0021] According to another aspect of the embodiment to achieve the above or other objects, a power conversion device includes a switching circuit including a first switching element and a second switching element connected in series between a first power line and a second power line; a voltage detection circuit connected to the first power line, the second power line and a first node, and configured to detect an input-side voltage; a constant current source connected to the first node; and a detection circuit connected to the first node, and configured to detect an abnormal signal based on a voltage of the first node that varies according to the detected input-side voltage; wherein the constant current source supplies a current mirror to the first node so that the voltage of the first node varies according to the detected input-side voltage.

[0022] The power conversion device may further include a driving unit that outputs a switching signal to drive the first switching element and the second switching element. The driving unit may drive the first switching element and the second switching element based on the detected abnormal signal.

[0023] The above driving unit can, during normal operation, turn on one of the first switching element and the second switching element and turn off the other switching element according to the switching signal. The detection circuit can, when the voltage of the first node is equal to or higher than the first set value, transmit the abnormal signal to the driving unit, and the driving unit can turn off the switched-on switching element according to the transmitted abnormal signal.

[0024] The effects of the abnormal signal blocking device and power conversion device according to the embodiment are described as follows.

[0025] According to at least one of the embodiments, a surge voltage can be detected and quickly blocked before the switching element is damaged by the surge voltage. Accordingly, damage to the switching circuit as well as to circuit elements such as a driving unit connected to the switching circuit can be prevented.

[0026] According to at least one of the embodiments, when an abnormal signal is detected by the abnormal signal detection circuit, the driving unit can block the surge voltage based on the abnormal signal. Accordingly, damage to the switching circuit as well as damage to circuit components such as the driving unit connected to the switching circuit can be prevented.

[0027] According to at least one of the embodiments, when an abnormal signal is detected, the surge voltage is not exposed to components within the abnormal signal detection circuit, such as a constant current source and a detection circuit, thereby preventing damage to these components.

[0028] According to at least one of the embodiments, a protection element can be used to prevent current from flowing to a detection circuit or a constant current source due to a distributed voltage distributed by a surge voltage. Accordingly, damage to components within an abnormal signal detection circuit, a constant current source, a detection circuit, etc. can be prevented by preventing them from being exposed to these components.

[0029] Fig. 1 is a circuit diagram illustrating an inverter according to an embodiment.

[0030] Fig. 2 is a circuit diagram illustrating a power conversion device according to the first embodiment.

[0031] Fig. 3a shows the waveform of the drain-source voltage of the second switching element in the first embodiment.

[0032] Fig. 3b shows the operation waveform of the first switching in the first embodiment.

[0033] Fig. 4 is a circuit diagram illustrating a power conversion device according to the second embodiment.

[0034] Figures 5a to 5c are circuit diagrams showing a protection element according to an embodiment.

[0035] Fig. 6a is a circuit diagram illustrating a constant current source according to an embodiment.

[0036] Fig. 6b is a circuit diagram illustrating a constant voltage source according to an embodiment.

[0037] Fig. 7a shows the waveform of the drain-source voltage of the second switching element in the second embodiment.

[0038] Fig. 7b shows the waveform of the voltage of the second node in the second embodiment.

[0039] Fig. 7c shows the operation waveform of the first switching in the second embodiment.

[0040] The sizes, shapes, and dimensions of components depicted in the drawings may differ from the actual components. Furthermore, even if the same components are depicted with different sizes, shapes, and dimensions across drawings, this is merely an example within the drawings, and the same components may have the same sizes, shapes, and dimensions across drawings.

[0041] Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers and redundant descriptions thereof will be omitted. The suffixes 'module' and 'part' used for components in the following description are given or used interchangeably in consideration of the ease of writing the specification, and do not have distinct meanings or roles in themselves. In addition, the attached drawings are intended to make it easier to understand the embodiments disclosed in the present specification, and the technical ideas disclosed in the present specification are not limited by the attached drawings. In addition, when an element such as a layer, region, or substrate is referred to as existing 'on' another element, this includes that it may be directly on the other element or that other intermediate elements may exist therebetween.

[0042] Hereinafter, “module”, “part”, etc. may be composed of “circuit” or “integrated circuit”. Accordingly, “module”, “part”, etc. may be used interchangeably with “circuit” or “integrated circuit”.

[0043]

[0044] Fig. 1 is a circuit diagram illustrating an inverter according to the first embodiment.

[0045] Referring to FIG. 1, the inverter (1000) according to the first embodiment can be applied to applications such as three-phase motors or compressors. The inverter (1000) may be a power conversion device or may be included in a power conversion device. The inverter (1000) may include a switching circuit.

[0046] The inverter (1000) according to the first embodiment can convert DC power into AC power and supply the converted AC power to the load (1200) to drive the load (1200). In the inverter (1000) according to the first embodiment, a converter may be connected to the input side to convert AC power into DC power. In this case, the DC power converted by the converter can be converted into AC power by the inverter (1000) and then used to drive the load (1200). The load (1200) may be a motor or an electric motor, but is not limited thereto.

[0047] The inverter (1000) according to the first embodiment may include a three-phase inverter, but is not limited thereto. At this time, a phase difference of 120 degrees may be present between the first phase, the second phase, and the third phase. The inverter (1000) according to the first embodiment may include a plurality of legs (100A, 100B, 100C). For example, the first leg (100A), the second leg (100B), and the third leg (100C) may be connected in parallel to a load (1200), i.e., a motor, through a first node (N1), a second node (N2), and a third node (N3), respectively. The first leg (100A) may include a first arm (100a) and a second arm (100b) that are connected in series to each other, the second leg (100B) may include a third arm (100c) and a fourth arm (100d) that are connected in series to each other, and the third leg (100C) may include a fifth arm (100e) and a sixth arm (100f) that are connected in series to each other. Here, the first arm (100a), the third arm (100c), and the fifth arm (100e) may be referred to as upper arms, and the second arm (100b), the fourth arm (100d), and the sixth arm (100f) may be referred to as lower arms. Each of the first arm (100a) to the sixth arm (100f) may be referred to as a switching module, a submodule, or the like.

[0048] The first arm (100a) to the sixth arm (100f) may each include switching elements (Q1 to Q6) and diodes (100a-2, 100b-2, 100c-2, 100d-2, 100e-2, 100f-2). The switching elements (Q1 to Q6) and the diodes (100a-2, 100b-2, 100c-2, 100d-2, 100e-2, 100f-2) may be formed simultaneously using the same semiconductor process. The switching elements (Q1 to Q6) may include power semiconductor elements.

[0049] In order for DC power to be converted into AC power by the inverter according to the first embodiment, the switching elements (Q1 to Q6) of each of the first arm (100a) to the sixth arm (100f) can be controlled to turn on / off.

[0050] For example, when the first switching element (Q1) of the first arm (100a) of the first leg (100A) is in the ON state, the fourth switching element (Q4) of the fourth arm (100d) of the second leg (100B) and / or the sixth switching element (Q6) of the sixth arm (100f) of the third leg (100C) may be in the ON state. Accordingly, DC power may be supplied to the first phase inductor of the motor.

[0051] For example, when the third switching element (Q3) of the third arm (100c) of the second leg (100B) is turned on, the sixth switching element (Q6) of the sixth arm (100f) of the third leg (100C) and / or the second switching element (Q2) of the second arm (100b) of the first leg (100A) may be turned on. Accordingly, DC power may be supplied to the second phase inductor of the motor. The second phase may be 120 degrees behind the first phase.

[0052] For example, when the fifth switching element (Q5) of the fifth arm (100e) of the third leg (100C) is turned on, the second switching element (Q2) of the second arm (100b) of the first leg (100A) and / or the fourth switching element (Q4) of the fourth arm (100d) of the second leg (100B) may be turned on. Accordingly, DC power may be supplied to the third phase inductor of the motor. The third phase may be 120 degrees behind the second phase.

[0053] Accordingly, AC power can be generated by the DC power supplied to each of the first phase inductor, the second phase inductor, and the third inductor.

[0054] Meanwhile, although not shown, in order to increase the internal pressure characteristics, the switching elements of each of the first arm (100a) to the sixth arm (100f), i.e., the power semiconductor elements (Q1 to Q6), may be provided in multiple numbers, each connected in series with each other.

[0055] Although not shown, in order to increase the current characteristics, the switching elements of each of the first arm (100a) to the sixth arm (100f), i.e., the power semiconductor elements (Q1 to Q6), may be provided in multiple numbers connected in parallel with each other.

[0056] Meanwhile, the switching elements (Q1 to Q6) and diodes (100a-2, 100b-2, 100c-2, 100d-2, 100e-2, 100f-2) constituting the first arm (100a) to the sixth arm (100f) can be packaged to form a power semiconductor module.

[0057] As an example, the first leg (100A), the second leg (100B), and the third leg (100C) can each be configured as power semiconductor modules. That is, the first arm (100a) and the second arm (100b) of the first leg (100A) can be packaged to configure a first power semiconductor module. The third arm (100c) and the fourth arm (100d) of the second leg (100B) can be packaged to configure a second power semiconductor module. The fifth arm (100e) and the sixth arm (100f) of the third leg (100C) can be packaged to configure a third power semiconductor module.

[0058] As another example, the first leg (100A), the second leg (100B), and the third leg (100C) can be configured as a single power semiconductor module. That is, the first arm (100a) and the second arm (100b) of the first leg (100A), the third arm (100c) and the fourth arm (100d) of the second leg (100B), and the fifth arm (100e) and the sixth arm (100f) of the third leg (100C) can be packaged to configure a single power semiconductor module.

[0059] Meanwhile, VDC is the input voltage, which can be, for example, DC voltage or surge voltage. CDC acts as a capacitor and can charge the input voltage (VDC).

[0060]

[0061] Fig. 2 is a circuit diagram illustrating a power conversion device according to the first embodiment. Fig. 3a shows the waveform of the drain-source voltage of the second switching element in the first embodiment. Fig. 3b shows the operating waveform of the first switching element in the first embodiment.

[0062] Referring to FIG. 2, the power conversion device (200) according to the first embodiment may include a switching circuit (210), an abnormal signal blocking device (207), etc. The abnormal signal blocking device (207) may be configured as a single integrated circuit as a controller, but is not limited thereto.

[0063] The switching circuit (210) may include a first switching element (Q1) and a second switching element (Q2) connected in series between a first power line (201) and a second power line (203). As illustrated in FIG. 1, a node between the first switching element (Q1) and the second switching element (Q2) may be connected to a load (1200). Each of the first switching element (Q1) and the second switching element (Q2) may include a power semiconductor element. The power semiconductor element may be formed of a silicon (Si) series, a silicon carbide (SiC) series, gallium nitride (GaN), or the like.

[0064] The six switching elements (Q1 to Q6) illustrated in FIG. 1 may be configured in pairs of two in the switching circuit (210) illustrated in FIG. 2. That is, the first switching element (Q1) and the second switching element (Q2) may be connected in series to each other as a first pair. The third switching element (Q3) and the fourth switching element (Q4) may be connected in series to each other as a second pair. The fifth switching element (Q5) and the sixth switching element (Q6) may be connected in series to each other as a third pair.

[0065] For convenience of explanation below, the description is limited to the first switching element (Q1) and the second switching element (Q2), but the remaining switching elements (Q3 to Q6) can also be applied equally to the embodiments described below.

[0066] When a surge voltage or the like is introduced through the input side (205), the abnormal signal blocking device (207) can quickly turn off the switching element that is currently on in the switching circuit (210), for example, the first switching element (Q1), thereby preventing damage to circuit elements such as the driving unit (220) or the switching circuit (210) due to the surge voltage or the like. Here, the surge voltage or the like may include at least one of a surge voltage, static electricity, overvoltage, and ripple voltage. For example, when lightning or friction occurs or the power supply is unstable, a surge voltage, static electricity, overvoltage, ripple voltage, and the like may be introduced through the input side (205).

[0067] Unless otherwise stated herein, surge voltage may mean at least one of surge voltage, static electricity, overvoltage and ripple voltage.

[0068] As illustrated in Fig. 1, when a surge voltage is applied through the input side (205) while the first switching element (Q1) and the fourth switching element (Q4) are currently on during normal operation, the abnormal signal blocking device (207) can turn off the first switching element (Q1) and the fourth switching element (Q4), which are each in the on state. In addition, the abnormal signal blocking device (207) can continuously maintain the second switching element (Q2), the third switching element (Q3), the fifth switching element (Q5), and the sixth switching element (Q6), which are each currently in the off state. Accordingly, since the surge voltage is not supplied into the switching circuit (210), damage to circuit elements such as the switching circuit (210), the driving unit (220), etc. can be prevented.

[0069] The abnormal signal blocking device (207) may include a driving unit (220), an abnormal signal detection circuit (230), etc. The driving unit (220) and the abnormal signal detection circuit (230) may be configured as one integrated circuit or may be configured as individual integrated circuits.

[0070] In an embodiment, the driving unit (220) may control not only the detection of an abnormal signal but also the switching operations of the first switching element (Q1) and the second switching element (Q2) of the switching circuit (210). Alternatively, the driving unit (220) may perform the detection operation of the abnormal signal, and a controller provided separately from the driving unit (220) may perform the switching operations of the first switching element (Q1) and the second switching element (Q2) of the switching circuit (210). In an embodiment, the driving unit (220) may drive the first switching element (Q1) and the second switching element (Q2) of the switching circuit (210) differently depending on normal operation or abnormal operation. For example, during normal operation, one of the first switching element (Q1) and the second switching element (Q2) may be turned on and the other may be turned off. For example, during abnormal operation, the first switching element (Q1) and the second switching element (Q2) may be turned off.

[0071] The driving unit (220) can output a switching signal to drive the first switching element (Q1) and the second switching element (Q2) during normal operation. The first switching element (Q1) and the second switching element (Q2) can be complementarily driven in response to the switching signal. For example, when the first switching element (Q1) is turned on, the second switching element (Q2) can be turned off. In this case, the fourth switching element (Q4) and / or the sixth switching element (Q6) can be turned on. The third switching element (Q2) and the fifth switching element (Q5) can be turned off. For example, when the first switching element (Q1) is turned off, the second switching element (Q2) can be turned on. In this case, the third switching element (Q3) and / or the fifth switching element (Q5) can be turned on. The fourth switching element (Q4) and the sixth switching element (Q6) can be turned off.

[0072] The abnormal signal detection circuit (230) can detect an abnormal signal. The abnormal signal can be detected based on one of surge voltage, static electricity, overvoltage, and ripple voltage.

[0073] When a surge voltage is introduced through the input side (205), the surge voltage can be quickly blocked to protect circuit elements such as the driving unit (220) and switching circuit (210).

[0074] To this end, in the embodiment, when a surge voltage is introduced through the input side (205), the abnormal signal detection circuit (230) can detect the surge voltage and detect an abnormal signal based on the detected surge voltage. The driving unit (220) can quickly turn off the switching element that is currently on, for example, the first switching element (Q1), based on the detected abnormal signal, thereby protecting circuit elements such as the driving unit (220) and the switching circuit (210). For example, the driving unit (220) can output an abnormal control signal based on the detected abnormal signal. The first switching element (Q1) that is currently on can be quickly turned off by the abnormal control signal.

[0075] Meanwhile, an abnormal signal detection circuit (230) may be connected between the first power line (201) and the second power line (203). When a surge voltage is input through the input side (205), the surge voltage may be supplied to the abnormal signal detection circuit (230). The abnormal signal detection circuit (230) may detect an abnormal signal based on the surge voltage. The detected abnormal signal may be transmitted to the driving unit (30).

[0076] The driving unit (220) can drive the switching circuit (210) according to the abnormal signal. That is, the driving unit (220) can output the abnormal signal to drive the first switching element (Q1) and the second switching element (Q2) in the switching circuit (210). For example, when the first switching element (Q1) is in the on state, the driving unit (220) can turn off the first switching element (Q1) in the on state according to the abnormal signal. For example, when the second switching element (Q2) is in the off state, the driving unit (220) can continuously maintain the second switching element (Q2) in the off state according to the abnormal signal.

[0077] As illustrated in FIGS. 3A and 3B, the abnormal signal blocking device (207) according to the first embodiment can be operated by dividing it into a normal section (TNO) and an abnormal section (TAB). The abnormal signal detection circuit (230) can detect the input side voltage (VDC) during the normal section (TNO) and detect the surge voltage during the abnormal section (TAB).

[0078] During the normal operation period (TNO), the first switching element (Q1) may be turned on and the second switching element (Q2) may be turned off. Alternatively, during the normal operation period (TNO), the first switching element (Q1) may be turned off and the second switching element (Q2) may be turned on.

[0079] If the first switching element (Q1) is turned on and the second switching element (Q2) is turned off, the input side voltage (VDC) can be supplied to the second switching element (Q2) via the first switching element (Q1). Accordingly, the drain-source voltage (VDS) of the second switching element (Q2) can have a predetermined level.

[0080] Meanwhile, the abnormal section (TAB) may be a section in which a surge voltage is introduced and the corresponding surge voltage is blocked. Specifically, the abnormal section (TAB) may include a first section (ST1), a second section (ST2), etc. The first section (ST1) may be a section in which a surge voltage is introduced and an abnormal signal is detected. The second section (ST2) may be a section in which the surge voltage is blocked based on the detected abnormal signal.

[0081] <Section 1 (ST1)>

[0082] When the switching circuit (210) is driven in normal operation, i.e., when the first switching element (Q1) is turned on and the second switching element (Q2) is turned off, a surge voltage may be introduced through the input side (205). In this case, the surge voltage may be supplied to the second switching element (Q2) through the first switching element (Q1). Accordingly, the drain-source voltage (VDS) of the second switching element (Q2) may increase from the level generated by the input side voltage (VDC). The abnormal signal detection circuit (230) may detect an abnormal signal by monitoring a change in the surge voltage.

[0083] <Second Section (ST2)>

[0084] Since the input side voltage (VDC) and the surge voltage are different, the abnormal signal detection circuit (230) can detect the input side voltage (VDC) and the surge voltage by distinguishing them from each other. For example, the surge voltage may be much higher than the input side voltage (VDC). For example, the input side voltage (VDC) may be several hundred volts, and the surge voltage may be at least several thousand volts.

[0085] A setpoint can be set to determine whether a surge voltage exists. The abnormal signal detection circuit (230) can detect an abnormal signal if the surge voltage is greater than the setpoint. The surge voltage may be greater than the input voltage (VDC) and may increase toward a peak. If the surge voltage increases in this manner and is greater than the setpoint, the abnormal signal detection circuit (230) can detect an abnormal signal. The abnormal signal can be transmitted to the driving unit (220).

[0086] Since the surge voltage is a very large voltage, when detecting an abnormal signal through the surge voltage, the abnormal signal detection circuit (230) or the driving unit (220) may be damaged by the surge voltage. Therefore, the surge voltage may be reduced to a stable voltage using a distribution method or the like, and the abnormal signal may be detected by comparing the reduced voltage with a set value, but this is not limited thereto.

[0087] The driving unit (220) can block the surge voltage based on the abnormal signal. That is, the driving unit (220) can turn off the first switching element (Q1) in the on state according to the abnormal signal. In addition, the driving unit (220) can continuously maintain the second switching element (Q2) in the off state. Since the surge voltage is blocked by the first switching element (Q1) and is not supplied to the second switching element (Q2), the drain-source voltage (VDS) of the second switching element (Q2) can be reduced. Since the drain-source voltage (VDS) of the second switching element (Q2) is reduced, the surge voltage becomes lower than the breakdown voltage of the second switching element (Q2), so that damage to the second switching element (Q2) can be prevented. Accordingly, damage to not only the switching circuit (210) but also the driving unit (220) can be prevented.

[0088] As illustrated in FIG. 3, the level of the reduced drain-source voltage (VDS) may be greater than the level of the drain-source voltage (VDS) during the normal period (TNO). The level of the reduced drain-source voltage (VDS) may discharge over time to become equal to the level of the drain-source voltage (VDS) during the normal period (TNO).

[0089] According to an embodiment, when a surge voltage is introduced through the input side (205), the abnormal signal detection circuit (230) detects the abnormal signal, and the driving unit (220) can quickly turn off the switching element that is currently on, for example, the first switching element (Q1), thereby protecting circuit elements such as the driving unit (220) and the switching circuit (210). As described above, when the first switching element (Q1) is on, the second switching element (Q2) is turned off, and therefore, the driving unit (220) can continuously maintain the off state of the second switching element (Q2).

[0090]

[0091] Fig. 4 is a circuit diagram illustrating a power conversion device according to a second embodiment. Figs. 5a to 5c are circuit diagrams illustrating a protection element according to an embodiment. Fig. 6a is a circuit diagram illustrating a constant current source according to an embodiment. Fig. 6b is a circuit diagram illustrating a constant voltage source according to an embodiment. Fig. 7a shows a waveform of a drain-source voltage of a second switching element according to the second embodiment. Fig. 7b shows a waveform of a voltage of a second node according to the second embodiment. Fig. 7c shows an operation waveform of a first switching element according to the second embodiment.

[0092] In the second embodiment, the detailed components of the abnormal signal detection circuit (230) are the same as in the first embodiment. In the second embodiment, components having the same functions as in the first embodiment are given the same drawing reference numerals and detailed descriptions are omitted.

[0093] Referring to FIG. 4, the power conversion device (201) according to the second embodiment may include a switching circuit (210), an abnormal signal blocking device (207), etc.

[0094] The switching circuit (210) may include a first switching element (Q1) and a second switching element (Q2) that are connected in series between the first power line (201) and the second power line (203). As described above, in addition to the first switching element (Q1) and the second switching element (Q2), third to sixth switching elements (Q3 to Q6 in FIG. 1) may also be included in the switching circuit (210).

[0095] The abnormal signal blocking device (207) may include a driving unit (220), an abnormal signal detection circuit (230), etc.

[0096] The driving unit (220) can drive the first switching element (Q1) and the second switching element (Q2) of the switching circuit (210) differently depending on normal or abnormal operation. For example, during normal operation, one of the first switching element (Q1) and the second switching element (Q2) may be turned on and the other may be turned off. For example, during abnormal operation, the first switching element (Q1) and the second switching element (Q2) may be turned off.

[0097] During normal operation, the driving unit (220) can output a switching signal to drive the first switching element (Q1) and the second switching element (Q2). For example, depending on the switching signal, one of the first switching element (Q1) and the second switching element (Q2) can be turned on and the other can be turned off. For example, when the first switching element (Q1) is turned on, the second switching element (Q2) can be turned off.

[0098] In the case of abnormal operation, the driving unit (220) can output various output signals, such as an abnormal signal, a maintenance signal, etc., of the abnormal signal detection circuit (230) to drive the first switching element (Q1) and the second switching element (Q2).

[0099] As a first example, when an abnormal signal is output from the abnormal signal detection circuit (230), the driving unit (220) can turn off the first switching element (Q1) currently in the on state according to the abnormal signal and maintain the second switching element (Q2) currently in the off state.

[0100] As a second example, when a maintenance signal is output from the abnormal signal detection circuit (230), the driving unit (220) can continuously maintain the first switching element (Q1) in the off state and the second switching element (Q2) in the off state according to the maintenance signal.

[0101] Meanwhile, although not shown, a maintenance state can be maintained for a certain period of time and then restored to the normal state using a maintenance signal and additionally set settings. This is described in detail with reference to Fig. 7.

[0102] Referring to FIG. 4, the abnormal signal detection circuit (230) may include a voltage detection circuit (235), a constant current source (270), a detection circuit (280), etc.

[0103] The constant current source (270) and the detection circuit (280) may be included in the driving unit (220) and configured as a single integrated circuit. The constant current source (270) and the detection circuit (280) may be configured as separate integrated circuits, independently of the driving unit (220).

[0104] The voltage detection circuit (235), the constant current source (270), and the detection circuit (280) may be included in the driving unit (220) and configured as a single integrated circuit. The voltage detection circuit (235), the constant current source (270), and the detection circuit (280) may be independently separated from the driving unit (220) and configured as separate integrated circuits.

[0105] The voltage detection circuit (235) may include a first impedance element (240), a second impedance element (250), a protection element (260), etc. The voltage detection circuit (235) may detect a voltage input to the input side (205). The protection element (260) may not be included in the voltage detection circuit (235) but may be provided separately. The voltage detection circuit (235), the constant current source (270), and the detection circuit (280) may be commonly connected to the first node (N11). The voltage (Vb) detected by the voltage detection circuit (235) is provided to the detection circuit (280), so that an abnormal signal can be detected by the detection circuit (280).

[0106]

[0107] Meanwhile, the first impedance element (240) and the second impedance element (250) can be connected between the first power line (201) and the second power line (203).

[0108] The first impedance element (240) may be connected between the first power line (201) and the second node (N21). The first impedance element (240) may be connected in parallel with the first switching element (Q1). When a surge voltage is applied through the input side (205), the surge voltage may be supplied to the first switching element (Q1) or the first impedance element (240).

[0109] A second impedance element (250) may be connected between a second node (N21) and a second power line (203). The second impedance element (250) may be connected in parallel with a second switching element (Q2). When a surge voltage is applied through the input side (205), the surge voltage may be supplied to the second switching element (Q2) or the second impedance element (250).

[0110] The first impedance element (240) and the second impedance element (250) may each include one or more resistors and / or one or more capacitors. The capacitors may block DC voltage and pass AC voltage. For example, when a surge voltage, which is an AC voltage, is introduced through the input side (205), the surge voltage may be supplied to the second node (N21) through the first impedance element (240) or the second impedance element (250).

[0111] The input side voltage (VDC) or surge voltage may be distributed by the first impedance element (240) and the second impedance element (250), so that the distributed voltage (Va) may be generated at the second node (N21). The distributed voltage (Va) may be smaller than the input side voltage (VDC) or the surge voltage. The degree of the smaller distributed voltage (Va) may vary depending on the design of the first impedance element (240) or the second impedance element (250). When the surge voltage is a high voltage of, for example, 1,000 V or more, the distributed voltage (Va) may be reduced to several tens of V to several hundred V.

[0112] The protection element (260) can protect the constant current source (270), the detection circuit (280), the driving unit (220), etc. from the surge voltage. As described above, the surge voltage is distributed by the first impedance element (240) and the second impedance element (250), so that the distributed voltage (Va) can be generated at the second node (N21). Although the distributed voltage (Va) is smaller than the surge voltage, it can still be large enough to damage the constant current source (270), the detection circuit (280), the driving unit (220), etc.

[0113] That is, when a surge voltage is introduced through the input side (205), the voltage (Va) distributed from the surge voltage is greater than the voltage of the second node (Vb), so that the current may flow to the first node (N11) instead of the second impedance element (250). The constant current source (270), the detection circuit (280), the driving unit (220), etc. may be damaged by this current.

[0114] To solve this problem, a protection element (260) may be provided. The protection element (260) may be connected between the first node (N11) and the second node (N21).

[0115] The protection element (260) prevents current from flowing from the second node (N21) to the first node (N11), thereby preventing damage to the constant current source (270), detection circuit (280), driving unit (220), etc. The detailed configuration of the protection element (260) will be described later.

[0116] A constant current source (270) may be connected to the first node (N11). The rectifier (270) may be connected between the driving unit (270) and the first node (N11). In the drawing, the constant current source (270) is provided separately from the driving unit (220), but may be included in the driving unit (220).

[0117] The constant current source (270) is connected to the driving unit (220) and can receive a power voltage from the driving unit (220). The constant current source (270) can output a mirror current (Iref) using the voltage supplied from the driving unit (220). The mirror current (Iref) output from the constant current source (270) can be supplied to the first node (N11). As illustrated in Fig. 6a, the constant current source (270) can include a voltage generation circuit (310) and a current mirror circuit (320). The voltage generation circuit (310) can generate a predetermined voltage using the power voltage supplied from the constant current source (270) and supply the generated voltage to the current mirror circuit (320). The current mirror circuit (320) can generate a mirror current (Iref) using the corresponding voltage. A constant mirror current (Iref) can be output by the current mirror circuit (320). The current mirror circuit (320) illustrated in the drawing is composed of two transistors, but may be composed of more transistors and various modifications may be possible.

[0118] A detection circuit (280) may be connected to a first node (N11). The detection circuit (280) may include, for example, a comparator, but is not limited thereto. For example, the voltage (Vb) of the first node (N11) may be supplied to a non-inverting (+) terminal of the comparator, and the first set value (Vref) may be supplied to an inverting (-) terminal of the comparator.

[0119] The detection circuit (280) can detect a detection signal based on the voltage (Vb) of the first node (N11) and the first set value (Vref). The detection signal may include an abnormal signal. The abnormal signal may be a signal that blocks a surge voltage so as not to damage the aforementioned circuit elements. The abnormal signal may be transmitted to the driving unit (220).

[0120] Specifically, the voltage (Va) of the second node (N21) may vary depending on the input side voltage (VDC). That is, the input side voltage (VDC) during normal operation and the input side voltage (VDC) during abnormal operation may be different. For example, the input side voltage (VDC) during abnormal operation may be much higher than the input side voltage (VDC) during normal operation. If the input side voltage (VDC) varies, the voltage (Va) of the second node (N21) may also vary. The voltage (Vb) of the first node (N11) may vary depending on the voltage (Va) of the second node (N21). If the voltage (Va) of the second node (N21) varies, the voltage (Vb) of the first node (N11) may also vary. Therefore, the detection circuit (280) can detect an abnormal signal based on the voltage (Vb) of the first node (N11) that varies depending on the input side voltage (VDC). That is, the voltage (Va) of the second node (N21) may fluctuate depending on the input side voltage (VDC), and accordingly, the voltage (Vb) of the first node (N11) may fluctuate. In this case, the detection circuit (280) may detect an abnormal signal based on the fluctuated voltage (Vb) of the first node (N11). The method of detecting the abnormal signal will be described in detail later.

[0121] The driving unit (220) can output an abnormal signal to drive the first switching element (Q1) and the second switching element (Q2) in the switching circuit (210). When an abnormal signal due to a surge voltage is detected while the first switching element (Q1) is turned on and the second switching element (Q2) is turned off during normal operation, the driving unit (220) can turn off the first switching element (Q1) in the turned-on state. The driving unit (220) can keep the second switching element (Q2) in the turned-off state turned off. Accordingly, the surge voltage is blocked, so that the switching circuit (210), the controller, etc. can be protected.

[0122]

[0123] Meanwhile, the protection element (260) can have various modification examples as shown in FIGS. 5a to 5c.

[0124] As illustrated in Fig. 5a, the protection element (260) may include a reverse voltage prevention element (301) connected to the second node (N21). The reverse voltage prevention element (301) may be connected between the first node (N11) and the second node (N21). The reverse voltage prevention element (301) may include a diode, but is not limited thereto. The cathode of the diode is connected to the second node (N21), so that reverse current does not flow from the second node (N21) to the first node (N11).

[0125] When a surge voltage is introduced through the input side (205), the voltage (Va) of the second node (N21) distributed by the surge voltage may be greater than the voltage (Vb) of the first node (N11). The reverse voltage prevention element (301) of the embodiment can protect the constant current source (270), the detection circuit (280), the driving unit (220), etc. by preventing current from flowing from the second node (N21) to the first node (N11).

[0126] The protection element (260) may include a voltage sensing element (302). The voltage sensing element (302) may be connected between the first node (N11) and the reverse voltage prevention element (301).

[0127] The voltage sensing element (302) may include a resistor. The resistor may have a predetermined resistance. The voltage of the second node (N21) and the voltage (Vb) of the first node (N11) may be different due to the resistor. The voltage sensing element (302) may generate a voltage (Vb) of the first node (N11) that is different from the voltage of the second node (N21).

[0128] The voltage of the second node (N21) may change during normal or abnormal operation. The voltage (Vb) of the first node (N11) may also change according to the change in the voltage of the second node (N21).

[0129] Below, the relationship between the voltage of the second node (N21) and the voltage (Vb) of the first node (N11) is explained using a formula.

[0130] The voltage of the second node (N21) can be expressed by mathematical expression 1.

[0131] [Mathematical Formula 1]

[0132] Va = (I1*Z2) + (I2*Z2)

[0133] Va is the voltage of the second node (N21), I1 is the current flowing through the protection element (260), and I1 may be the current flowing through the first impedance element (240) and the second impedance element (250). I2 may be the current flowing through the protection element. I2 may be the same as the mirror current (Iref), but is not limited thereto. I1 may be the first current, and I2 may be the second current.

[0134] I1 can be expressed by mathematical formula 2.

[0135] [Equation 2]

[0136] I1 = VDC / (Z1+Z2)

[0137] VDC is the input side voltage, Z1 may be the value of the first impedance element (240), and Z2 may be the value of the second impedance element (250). Vb may be the voltage (Vb) of the first node (N11), and Z3 may be the value of the third impedance element included in the protection element (260). The third impedance element may be a resistor included in the voltage sensing element (302).

[0138] If we substitute mathematical expression 2 into mathematical expression 1 and rearrange it, it can be expressed as mathematical expression 3.

[0139] [Equation 3]

[0140] Va = [VDC / (Z1+Z2)]*Z2 + (I2*Z2)

[0141] Meanwhile, the voltage (Vb) of the first node (N11) can be expressed by mathematical expression 4.

[0142] [Equation 4]

[0143] Vb = (I2*Z3) + Va

[0144] If we substitute mathematical expression 3 into mathematical expression 4 and rearrange it, we can express it as mathematical expression 5.

[0145] [Equation 5]

[0146] Vb = (Z2+Z3)*I2 + [VDC / (Z1+Z2)]*Z2

[0147] Meanwhile, since I2 is equal to Iref, Equation 5 can be expressed as Equation 6.

[0148] [Equation 6]

[0149] Vb = (Z2+Z3)*Iref + [VDC / (Z1+Z2)]*Z2

[0150] Z1, Z2, Z3, and Iref can be constants. From Equation 6, the voltage (Vb) of the first node (N11) can change according to a change in the input side voltage (VDC).

[0151] As shown in mathematical expression 6, since the mirror current (Iref) provided from the constant current source (270) has a constant value, the voltage (Vb) of the first node (N11) is related only to the input side voltage (VDC), so that the detection performance of an abnormal signal can be improved.

[0152] The input side voltage (VDC) may be a DC voltage output from a front end, such as a converter, during normal operation. A surge voltage may also flow into the input side (205). Therefore, as the input side voltage (VDC) changes, such as a DC voltage or a surge voltage, the voltage (Vb) of the first node (N11) may also change.

[0153] As described above, the voltage of the second node (N21) may be a DC voltage or a voltage (Va) to which a surge voltage is distributed.

[0154] As an example, the voltage of the second node (N21) distributed by the DC voltage may be less than the voltage (Vb) of the first node (N11).

[0155] As another example, when a surge voltage is introduced through the input side (205), the voltage of the second node (N21) may become greater than the voltage of the second node (N21) distributed by the DC voltage. That is, the voltage of the second node (N21) changes, and accordingly, the voltage (Vb) of the first node (N11) may change. As described above, the detection circuit (280) may monitor whether the voltage (Vb) of the first node (N11) is higher than the first set value (Vref). If the voltage (Vb) of the first node (N11) is higher than the first set value (Vref), an abnormal signal for protecting the circuit elements may be output to the driving unit (220).

[0156]

[0157] Meanwhile, as illustrated in FIG. 5b, the protection element (260) may include a reverse voltage prevention element (301), a voltage sensing element (302), a DC voltage blocking element (303), etc. For example, the reverse voltage prevention element (301), the voltage sensing element (302), and the DC voltage blocking element (303) may be connected between the second node (N21) and the first node (N11). The connection order of the reverse voltage prevention element (301), the voltage sensing element (302), and the DC voltage blocking element (303) may be changed.

[0158] Since the reverse voltage prevention element (301) and the voltage sensing element (302) are illustrated in Fig. 5a, further description is omitted.

[0159] The DC voltage blocking element (303) is connected between the voltage sensing element (302) and the first node (N11), and can block the DC voltage among the voltages of the second node (N21).

[0160] As illustrated in FIG. 5c, the protection element (260) may include a reverse voltage prevention element (301), a voltage sensing element (302), a frequency filter element (304), etc. For example, the reverse voltage prevention element (301) and the voltage sensing element (302) may be connected between the second node (N21) and the first node (N11). For example, the frequency filter element (304) may be connected in parallel with the voltage sensing element (302) at the first node (N11).

[0161] Since the reverse voltage prevention element (301) and the voltage sensing element (302) are illustrated in Fig. 5a, further description is omitted.

[0162] The frequency filter element (304) can selectively supply a voltage of a specific frequency band among the voltages of the second node (N21) to the first node (N11).

[0163] The DC voltage blocking element (303) or the frequency filter element (304) is a component for removing noise, and a voltage with noise removed for detecting an abnormal signal can be generated at the first node (N11) by the DC voltage blocking element (303) or the frequency filter element (304).

[0164]

[0165] Meanwhile, the first set value (Vref) may be provided from a constant voltage source (290). The constant voltage source (290) may be connected to the ground of the driving unit (220), thereby allowing the constant voltage source (290) to operate stably and more efficiently. The constant voltage source (290) may provide a predetermined power voltage relative to the ground voltage from the driving unit (220) and output the first set value (Vref) using the power voltage. The constant voltage source (290) may include a voltage generation circuit (330), a constant voltage generation circuit (330), a voltage regulator (340), etc., as illustrated in FIG. 6B. FIG. 6B is an example, and various modifications of the constant voltage source (290) are possible.

[0166] The voltage generation circuit (330) can generate a voltage for generating a constant voltage. The constant voltage generation circuit (330) includes, but is not limited to, two transistors (331, 333) and one resistor (332). One of the two transistors may be a driving transistor (331), and the other may be a diode-type transistor (333). When the driving transistor is turned on by the voltage generated by the voltage generation circuit (330), a constant voltage determined by the resistance value of the resistor (332) and the current flowing through the diode-type transistor (333) may be output through the node (N31). A constant constant voltage may be generated by the resistor (332) and the diode-type transistor (333). The voltage regulator (340) can adjust the magnitude of the constant voltage output from the node (N31).

[0167]

[0168] Hereinafter, the operation of the abnormality detection blocking device according to the embodiment will be described in detail with reference to FIGS. 1 and 7.

[0169] Referring to FIG. 1 and FIG. 7, the abnormal signal blocking device (207) according to the second embodiment can be operated by dividing it into a normal section (TNO) and an abnormal section (TAB).

[0170] The operation of the normal section (TNO) has been described in the first embodiment (Fig. 2, Fig. 3), so a detailed description is omitted.

[0171] The abnormal section (TAB) may be a section in which a surge voltage is introduced and the corresponding surge voltage is blocked. Specifically, the abnormal section (TAB) may include a first section (ST1), a second section (ST2), a third section (ST3), a fourth section (ST4), etc. The first section (ST1) may be a section in which a surge voltage is introduced and an abnormal signal is detected. The second section (ST2) may be a section in which the surge voltage is blocked based on the detected signal. The third section (ST3) may be a section in which the return to normal operation is delayed in consideration of a surge voltage margin, etc. The fourth section (ST4) may be a section in which the drain-source voltage (VDS) of the switching element that was turned on from off is discharged when the normal operation is returned.

[0172] <Section 1 (ST1)>

[0173] As described above, during the normal period (TNO), the first switching element (Q1) can be turned on and the second switching element (Q2) can be turned off.

[0174] When a surge voltage is introduced through the input side (205), the surge voltage can be supplied to the second switching element (Q2) through the first switching element (Q1). Accordingly, the drain-source voltage (VDS) of the second switching element (Q2) can increase.

[0175] The surge voltage may be distributed by the first impedance element (240) and the second impedance element (250), so that the distributed voltage (Va) may be generated at the second node (N21). As the surge voltage increases during the first section (ST1), the voltage at the second node (N21) may increase, and thus the voltage (Vb) at the first node (N11) may increase.

[0176] <Second Section (ST2)>

[0177] For example, the detection circuit (280) can detect an abnormal signal when the surge voltage is higher than the first set value (Vref). The abnormal signal can be transmitted to the driving unit (220).

[0178] The driving unit (220) can block the surge voltage based on the abnormal signal. That is, the driving unit (220) can turn off the first switching element (Q1) in the on state according to the abnormal signal. The driving unit (220) can maintain the off state of the second switching element (Q2) according to the abnormal signal. Accordingly, since the surge voltage is not supplied to the second switching element (Q2), the drain-source voltage (VDS) of the second switching element (Q2) can be reduced. Since the drain-source voltage (VDS) of the second switching element (Q2) is reduced, damage to the second switching element (Q2) due to the drain-source voltage (VDS) exceeding the breakdown voltage of the second switching element (Q2) can be prevented. In addition, damage to the control circuit, etc. due to the current rapidly increased by the breakdown voltage can be prevented.

[0179] <Section 3 (ST3)>

[0180] The surge voltage may decrease after passing the peak. Accordingly, the voltage of the second node (N21) may decrease, and the voltage (Vb) of the first node (N11) may also decrease.

[0181] The detection circuit (280) can detect a maintenance signal when the voltage of the first node (N11) is lower than the first set value (Vref). The maintenance signal can be transmitted to the driving unit (220).

[0182] Meanwhile, a second set value (SV) may be set in consideration of the hysteresis characteristics of each of the first switching element (Q1) and the second switching element (Q2) within the switching circuit (210). The hysteresis characteristics may mean that the on level determined by increasing the input voltage and the off level determined by decreasing the input voltage are different.

[0183] Accordingly, the second set value (SV) can be set by considering the hysteresis characteristics of each of the first switching element (Q1) and the second switching element (Q2) in the switching circuit (210).

[0184] As an example, the second set value (SV) can be set to a value smaller than the first set value (Vref) in consideration of the hysteresis characteristics of each of the first switching element (Q1) and the second switching element (Q2).

[0185] As another example, the second setpoint (SV) may be set to a point in time delayed by a certain amount of time from when the voltage (Vb) of the first node (N11) is less than the first setpoint (Vref).

[0186] When the driving unit (220) receives a maintenance signal, it can maintain the first switching element (Q1) in the off state during the third period (ST3). The driving unit (220) can maintain the second switching element (Q2) in the off state.

[0187] <Section 4 (ST4)>

[0188] The driving unit (220) can turn on the first switching element (Q1) in the off state based on the second set value (SV). At this time, the off state of the second switching element (Q2) can be maintained. If the second switching element (Q2) in the off state is turned on, the off state of the first switching element (Q1) can be maintained.

[0189] As described above, the second set value (SV) may be set to a value smaller than the first set value (Vref) in consideration of the hysteresis characteristics of each of the first switching element (Q1) and the second switching element (Q2). In addition, although not shown, the voltage (Vb) of the first node (N11) may be transmitted to the driving unit (220). In this case, the driving unit (220) determines whether the voltage (Vb) of the first node (N11) is less than the second set value (SV), and if the voltage (Vb) of the first node (N11) is less than the second set value (SV), the driving unit may turn on the first switching element (Q1) in the off state. In addition, the off state of the second switching element (Q2) may be maintained. Accordingly, the first switching element (Q1) and the second switching element (Q2) may operate normally after the surge voltage is removed.

[0190] Meanwhile, as described above, the second set value (SV) may be set to a point in time delayed by a certain amount of time from when the voltage (Vb) of the first node (N11) is less than the first set value (Vref). In this case, the driving unit (220) may receive a sustain signal from the detection circuit (280) when the voltage (Vb) of the first node (N11) is less than the first set value (Vref). The driving unit (220) may count from the point in time of receiving the sustain signal, and when the counted value becomes the second set value (SV), the driving unit may turn on the first switching element (Q1) in the off state.

[0191]

[0192] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the embodiments should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalency range of the embodiments are intended to be included within the scope of the embodiments.

Claims

1. A voltage detection circuit connected to a first power line, a second power line, and a first node, and detecting an input side voltage between the first power line and the second power line; a constant current source connected to the first node; and A detection circuit connected to the first node and detecting an abnormal signal based on the voltage of the first node that fluctuates according to the detected input side voltage; The above constant current source is, Supplying a current mirror to the first node so that the voltage of the first node varies according to the sensed input side voltage. Anomaly signal blocking device.

2. In paragraph 1, The above detection circuit includes a comparator, Anomaly signal blocking device.

3. In paragraph 1, Further comprising a driving unit that outputs a switching signal to drive the first switching element and the second switching element; The first switching element and the second switching element are connected in series between the first power line and the second power line, The above driving part, Driving the first switching element and the second switching element based on the detected abnormal signal. Anomaly signal blocking device.

4. In paragraph 3, The above driving part, During normal operation, one of the first switching element and the second switching element is turned on and the other switching element is turned off according to the switching signal. The above detection circuit, If the voltage of the first node is greater than or equal to the first set value, the abnormal signal is transmitted to the driving unit, The above driving part, Turning off the switched element according to the transmitted abnormal signal. Anomaly signal blocking device.

5. In paragraph 4, The above detection circuit, If the voltage of the first node is less than the first set value, a maintenance signal is transmitted to the driving unit, The above driving part, Maintaining the off switching element based on the transmitted maintenance signal; Anomaly signal blocking device.

6. In paragraph 5, The above driving part, Turning on the switching element that maintains the off state based on the second set value set by using the hysteresis characteristic of each of the first switching element and the second switching element, Anomaly signal blocking device.

7. In paragraph 4, A constant voltage source connected to the ground of the above driving unit and obtaining the first set value; Anomaly signal blocking device.

8. In paragraph 3, The above constant current source is connected to the driving unit to receive the power voltage. Anomaly signal blocking device.

9. In paragraph 1, The above voltage detection circuit, A first impedance element between the first power line and the second node; a second impedance element between the second node and the second power line; and A protection element is included between the first node and the second node; Anomaly signal blocking device.

10. In paragraph 9, The above protection device is, including a reverse voltage prevention element connected to the second node; Anomaly signal blocking device.

11. In paragraph 10, The above protection device is, further comprising a voltage sensing element connected to the reverse voltage prevention element; Anomaly signal blocking device.

12. In paragraph 11, The above protection device is, Further comprising a DC voltage blocking element connected between the voltage sensing element and the first node; Anomaly signal blocking device.

13. In paragraph 11, The above protection device is, Further comprising a frequency filter element connected in parallel with the voltage sensing element at the first node; Anomaly signal blocking device.

14. A switching circuit including a first switching element and a second switching element connected in series between a first power line and a second power line; A voltage detection circuit connected to the first power line, the second power line and the first node, and detecting an input side voltage; a constant current source connected to the first node; and A detection circuit connected to the first node and detecting an abnormal signal based on the voltage of the first node that fluctuates according to the detected input side voltage; The above constant current source is, Supplying a current mirror to the first node so that the voltage of the first node varies according to the sensed input side voltage. Power conversion device.

15. In paragraph 14, Further comprising a driving unit that outputs a switching signal to drive the first switching element and the second switching element; The above driving part, Driving the first switching element and the second switching element based on the detected abnormal signal. Power conversion device.

16. In paragraph 15, The above driving part, During normal operation, one of the first switching element and the second switching element is turned on and the other switching element is turned off according to the switching signal. The above detection circuit, If the voltage of the first node is greater than or equal to the first set value, the abnormal signal is transmitted to the driving unit, The above driving part, Turning off the switched element according to the transmitted abnormal signal. Power conversion device.

17. In paragraph 16, The above detection circuit, If the voltage of the first node is less than the first set value, a maintenance signal is transmitted to the driving unit, The above driving part, Maintaining the off switching element based on the transmitted maintenance signal; Power conversion device.

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