Abnormal signal blocking device and power conversion device

Abstract

This abnormal signal blocking device may include a voltage detection circuit, a constant voltage source, and a detection circuit. The voltage detection circuit may be connected to a first power line, a second power line, and a first node to output a detection voltage according to a voltage input from an input side between the first power line and the second power line. The constant voltage source may be connected to a second node to supply a constant voltage. The detection circuit may be connected to the first node and the second node to detect an abnormal signal.

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 current, which flows due to the breakdown voltage of the switching element due to the surge voltage. Consequently, there is a problem that the switching element, or the driving unit or circuit elements connected to the switching element, may be damaged by 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 outputting a detection voltage according to a voltage input from an input side between the first power line and the second power line; a constant voltage source connected to a second node, and supplying a constant voltage; and a detection circuit connected to the first node and the second node, and detecting an abnormal signal.

[0009] The detection circuit may include an amplifier having a non-inverting terminal connected to the second node and an inverting terminal connected to the first node.

[0010] The above abnormal signal blocking device further includes a driving unit that outputs a switching signal to drive a first switching element and a second switching element, wherein the first switching element and the second switching element can be connected in series between the first power line and the second power line.

[0011] The above driving unit can turn off the switching element currently in the on state among the first switching element and the second switching element when an abnormal signal is detected based on the comparison result between the constant voltage and the detection voltage.

[0012] The above driving unit can turn on the switching element in the off state again when it is detected that the abnormal signal has disappeared based on the comparison result between the constant voltage and the detection voltage.

[0013] The above abnormal signal blocking device may further include a protection circuit connected between the first node and the second node to block an abnormal voltage.

[0014] The above protection circuit may include a reverse voltage prevention element connected to the first node.

[0015] The above protection circuit may further include a voltage sensing element connected to the reverse voltage prevention element.

[0016] The above protection circuit may further include a direct current voltage blocking element connected to the voltage sensing element.

[0017] The above protection circuit may further include a frequency filter element connected to the reverse voltage prevention element.

[0018] According to another aspect of the embodiment, 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 outputting a detection voltage according to a voltage input at an input side between the first power line and the second power line; a constant voltage source connected to the second node, and supplying a constant voltage; and a detection circuit connected to the first node and the second node, and detecting an abnormal signal.

[0019] The power conversion device further includes a driving unit that outputs a switching signal to drive the first switching element and the second switching element, and the driving unit can turn off a switching element that is currently on among the first switching element and the second switching element when an abnormal signal is detected based on a comparison result between the constant voltage and the detection voltage.

[0020] The power conversion device may further include a protection circuit connected between the first node and the second node to block an abnormal voltage.

[0021] The effects of the abnormal signal blocking device and power conversion device according to the embodiment are described as follows.

[0022] 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.

[0023] According to at least one of the embodiments, when an abnormal signal is detected in the 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.

[0024] According to at least one of the embodiments, when an abnormal signal is detected, the surge voltage is not exposed to components within the signal detection circuit, such as a voltage source and a detection circuit, thereby preventing damage to these components.

[0025] According to at least one of the embodiments, a protection circuit can be used to prevent current from flowing to a detection circuit or a voltage regulator due to a distributed voltage caused by a surge voltage. Accordingly, damage to components within a signal detection circuit, a voltage regulator, a detection circuit, etc. can be prevented by preventing them from being exposed to these components.

[0026] Fig. 1 is a circuit diagram illustrating an inverter according to an embodiment.

[0027] FIG. 2 is a circuit diagram illustrating an abnormal signal blocking device and a power conversion device according to the first embodiment.

[0028] Fig. 3a shows the waveform of the drain-source voltage of the second switching element in the first embodiment.

[0029] Fig. 3b shows the operating waveform of the first switching element in the first embodiment.

[0030] Fig. 4 is a circuit diagram illustrating an abnormal signal blocking device and a power conversion device according to the second embodiment.

[0031] Figure 5a shows the current flowing in the protection circuit when a surge voltage occurs.

[0032] Figure 5b shows the voltage of the protection circuit when a surge voltage occurs.

[0033] Figure 5c shows the voltage of the first node and the voltage of the second node when a surge voltage occurs.

[0034] Figures 6a to 6c are circuit diagrams illustrating a protection circuit according to an embodiment.

[0035] Fig. 7 is a circuit diagram illustrating a constant voltage source according to an embodiment.

[0036] Fig. 8a shows the waveform of the drain-source voltage of the second switching element in the second embodiment.

[0037] Figure 8b shows the waveforms of the voltage of the first node and the voltage of the second node in the second embodiment.

[0038] Fig. 8c shows the operating waveform of the first switching element in the second embodiment.

[0039] Fig. 9 is a circuit diagram illustrating an abnormal signal blocking device and a power conversion device according to the third 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] Unless otherwise stated herein, surge voltage may mean at least one of surge voltage, static electricity, overvoltage and ripple voltage.

[0045] Fig. 1 is a circuit diagram illustrating an inverter according to the first embodiment.

[0046] Referring to FIG. 1, an inverter (1000) according to an embodiment can be applied to applications such as a three-phase motor or a compressor. The inverter (1000) can be included in a power conversion device or a power conversion device. The inverter (1000) can include a switching circuit.

[0047] An inverter (1000) according to an embodiment may convert DC power into AC power and supply the converted AC power to a load (1200) to drive the load (1200). In the inverter (1000) according to an 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 may 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.

[0048] The inverter (1000) according to the embodiment may include a three-phase inverter, but is not limited thereto. In this case, 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 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 the load (1200), i.e., the motor, through the first node (N1), the second node (N2), and the 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.

[0049] 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.

[0050] In order for DC power to be converted into AC power by the inverter (1000) according to the 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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).

[0061]

[0062] [Example 1]

[0063] Fig. 2 is a circuit diagram illustrating an abnormal signal blocking device and 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.

[0064] 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, but is not limited thereto.

[0065] 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.

[0066] In the switching circuit (210), a plurality of switching elements (Q1 to Q6) illustrated in FIG. 1 may be configured in pairs of two. That is, a first switching element (Q1) and a second switching element (Q2) may be connected in series to each other as a first pair. A third switching element (Q3) and a fourth switching element (Q4) may be connected in series to each other as a second pair. A fifth switching element (Q5) and a sixth switching element (Q6) may be connected in series to each other as a third pair.

[0067] 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.

[0068] When an abnormal signal, such as a surge voltage, 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, etc. Here, the surge voltage, etc. 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, etc. may be introduced through the input side (205).

[0069] As illustrated in Fig. 1, when a surge voltage is introduced through the input side (205) while the first switching element (Q1) and the fourth switching element (Q4) are each turned on during normal operation, the abnormal signal blocking device (207) can turn off the first switching element (Q1) and the fourth switching element (Q4) that are currently on. 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) that are currently off. Accordingly, since the surge voltage is not supplied into the switching circuit (210), damage to circuit elements such as the switching circuit (210) and the driving unit (220) can be prevented.

[0070] The abnormal signal blocking device (207) may include a driving unit (220), a signal detection circuit (230), etc. The driving unit (220) may not be included in the abnormal signal blocking device (207) and may be provided separately. The driving unit (220) and the signal detection circuit (230) may be configured as a single integrated circuit or may be configured as individual integrated circuits.

[0071] In an embodiment, the signal detection circuit (230) can detect an abnormal signal, such as a surge voltage, input through the input side (205).

[0072] In an embodiment, the driving unit (220) can control not only the detection of an abnormal signal based on a signal provided from a signal detection circuit (230), but also the switching operation of each of the first switching element (Q1) and the second switching element (Q2) of the switching circuit (210).

[0073] 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. Normal operation may refer to an operation when an input side voltage (VDC) is input through the input side (205), and abnormal operation may refer to an operation when an abnormal signal such as a surge voltage is input through the input side (205).

[0074] 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.

[0075] Specifically, 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, as shown in FIG. 1, the fourth switching element (Q4) and / or the sixth switching element (Q6) can be turned on, and 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, and the fourth switching element (Q4) and the sixth switching element (Q6) can be turned off.

[0076] The signal detection circuit (230) can detect an abnormal signal input through the input side (205). The abnormal signal may be one of surge voltage, static electricity, overvoltage, and ripple voltage.

[0077] 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).

[0078] To this end, in the embodiment, when a surge voltage is introduced through the input side (205), the signal detection circuit (230) can detect the surge voltage and detect an abnormal signal based on the detected surge voltage. When an abnormal signal is detected, the signal detection circuit (230) can output an abnormal control signal to the driving unit (220). The signal detection circuit (230) can include a controller to determine whether or not an abnormal signal is present and to generate an abnormal control signal, etc.

[0079] The driving unit (220) can protect circuit elements such as the driving unit (220) and the switching circuit (210) by quickly turning off a switching element that is currently on, for example, the first switching element (Q1), based on an abnormal control signal provided from the signal detection circuit (230). For example, the driving unit (220) can output an abnormal driving signal based on the abnormal control signal provided from the signal detection circuit (230). The first switching element (Q1) that is currently on can be quickly turned off by the abnormal driving signal.

[0080] Meanwhile, a 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 signal detection circuit (230). The signal detection circuit (230) may detect an abnormal signal through a detection voltage obtained based on the surge voltage, and may generate an abnormal control signal when an abnormal signal is detected. The abnormal control signal may be transmitted to the driving unit (220).

[0081] The driving unit (220) can output an abnormal driving signal to drive the switching circuit (210) based on the abnormal control signal transmitted from the signal detection circuit (230). That is, the driving unit (220) can output an abnormal driving 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 currently in an on state, the driving unit (220) can turn off the first switching element (Q1) in the on state according to the abnormal driving signal. For example, when the second switching element (Q2) is currently in an off state, the driving unit (220) can continuously maintain the off state of the second switching element (Q2) according to the abnormal driving signal. Therefore, since the surge voltage is not supplied into the switching circuit (210), damage to circuit elements such as a controller can be prevented.

[0082] 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). During the normal section (TNO), the first switching element (Q1) and the second switching element (Q2) in the switching circuit (210) can be normally driven according to the switching signal provided from the driving unit (220). During the abnormal section (TAB), both the first switching element (Q1) and the second switching element (Q2) in the switching circuit (210) can be turned off according to the abnormal driving signal provided from the driving unit (220), thereby blocking the surge voltage.

[0083] The signal detection circuit (230) can perform a signal detection operation in a normal section (TNO) and an abnormal section (TAB). For example, the signal detection circuit (230) can detect the input side voltage (VDC) input through the input side (205) during the normal section (TNO). The signal detection circuit (230) can detect the surge voltage introduced through the input side (205) during the abnormal section (TAB).

[0084] Specifically, during the normal 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 period (TNO), the first switching element (Q1) may be turned off and the second switching element (Q2) may be turned on.

[0085] When 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 (hereinafter, referred to as the first level).

[0086] Meanwhile, the abnormal section (TAB) may be a section where a surge voltage is applied 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 where a surge voltage is applied and an abnormal signal is detected. The second section (ST2) may be a section where the surge voltage is blocked when an abnormal signal is detected.

[0087] <Section 1 (ST1)>

[0088] During the normal operation (TNO), when the first switching element (Q1) of the switching circuit (210) 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 first level. Meanwhile, the signal detection circuit (230) may monitor the change in the surge voltage to obtain an abnormal control signal.

[0089] <Second Section (ST2)>

[0090] Since the input side voltage (VDC) and the surge voltage are different, the 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 hundreds of V, and the surge voltage may be at least thousands of V or more. The signal detection circuit (230) can obtain an abnormal control signal by using a change in voltage or current considering the surge voltage. This will be described in detail in the second embodiment (Fig. 4) and the third embodiment (Fig. 9). The abnormal control signal may be transmitted to the driving unit (220).

[0091] When an abnormal signal is detected by directly utilizing a surge voltage, the signal detection circuit (230) or the driving unit (220) may be damaged by a surge voltage of at least several thousand V or more. Therefore, after the surge voltage is reduced to a stable voltage using a distribution method, an abnormal signal can be detected by utilizing a change in voltage or current that takes into account the reduced voltage.

[0092] The driving unit (220) can block the surge voltage based on the abnormal control signal. That is, the driving unit (220) can turn off the first switching element (Q1) in the on state according to the abnormal control signal. In addition, the driving unit (220) can continuously maintain the off state of the second switching element (Q2). Since the surge voltage is not supplied to the switching circuit (210), the drain-source voltage (VDS) of the second switching element (Q2) is reduced, so that an avalanche current due to the breakdown voltage is not generated. Accordingly, damage to not only the switching circuit (210) but also the signal detection circuit (230) connected to the switching circuit (210) or the driving unit (220) can be prevented.

[0093] 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), i.e., the first level. The level of the reduced drain-source voltage (VDS) may discharge over time to become equal to the first level, but is not limited thereto.

[0094] According to an embodiment, when a surge voltage is introduced through the input side (205), the signal detection circuit (230) can detect an abnormal signal. That is, the signal detection circuit (230) can output an abnormal control signal to the driving unit (220). The driving unit (220) can protect circuit elements such as the driving unit (220), the switching circuit (210), etc. by quickly turning off the first switching element (Q1) currently in the on state and maintaining the second switching element (Q2) currently in the off state according to the abnormal control signal.

[0095]

[0096] [Example 2]

[0097] Fig. 4 is a circuit diagram illustrating an abnormal signal blocking device and a power conversion device according to a second embodiment. Figs. 6a to 6c are circuit diagrams illustrating a protection circuit according to an embodiment. Fig. 7 is a circuit diagram illustrating a constant voltage source according to an embodiment. Fig. 8a shows a waveform of a drain-source voltage of a second switching element according to the second embodiment. Fig. 8b shows waveforms of a voltage of a first node and a voltage of a second node according to the second embodiment. Fig. 8c shows an operating waveform of the first switching element according to the second embodiment.

[0098] In the second embodiment, the detailed components of the 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.

[0099] 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.

[0100] 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).

[0101] The abnormal signal blocking device (207) may include a driving unit (220), a signal detection circuit (230), etc.

[0102] 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 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.

[0103] Specifically, 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.

[0104] In the case of abnormal operation, the driving unit (220) can output various output signals of the signal detection circuit (230), such as an abnormal control signal, a return control signal, etc., to drive the first switching element (Q1) and the second switching element (Q2).

[0105] When an abnormal control signal is output from the 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 control signal and maintain the off state of the current second switching element (Q2).

[0106] When a return control signal is output from the signal detection circuit (230), the driving unit (220) can turn on the first switching element (Q1) in the off state according to the return control signal.

[0107] Meanwhile, at the time of occurrence of a normal return signal, the first switching element (Q1) may be turned off and the second switching element (Q2) may be turned on during normal operation. In this case, the driving unit (220) may turn on the second switching element (Q2) in the off state and maintain the first switching element (Q1) in the off state according to the return control signal.

[0108] Referring to FIG. 4, the signal detection circuit (230) may include a voltage detection circuit (235), a protection circuit (260), a constant voltage source (270), a detection circuit (280), etc.

[0109] The constant voltage source (270) and the detection circuit (280) may be included in the driving unit (220) and configured as a single integrated circuit. The constant voltage source (270) and the detection circuit (280) may be configured as separate integrated circuits, independently of the driving unit (220).

[0110] The voltage detection circuit (235), the protection circuit (260), the constant voltage 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 protection circuit (260), the constant voltage source (270), and the detection circuit (280) may be independently separated from the driving unit (220) and configured as separate integrated circuits.

[0111] The voltage detection circuit (235) may include a first impedance element (240), a second impedance element (250), etc. The voltage detection circuit (235) may detect a voltage input to the input side (205) and output a detection voltage (Va). The voltage detection circuit (235) and the detection circuit (280) may be commonly connected to a first node (N11). The detection voltage (Va) detected by the voltage detection circuit (235) is provided to the detection circuit (280), so that the difference value between the positive voltage and the detection voltage (Va) may be obtained by the detection circuit (280). The first node (N11) may be an output terminal of the voltage detection circuit (235) or may be connected to an output terminal. The first node (N11) may be an inverting (-) terminal of the detection circuit (280) or may be connected to an inverting (-) terminal. The detection voltage (Va) can change depending on the change in the voltage input to the input side (205). That is, the detection voltage (Va) can change depending on the voltage input to the input side, such as the input side voltage (VDC) or surge voltage.

[0112] 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).

[0113] A first impedance element (240) may be connected between a first power line (201) and a first node (N11). The first impedance element (240) may be connected in parallel with a first switching element (Q1). When a surge voltage is introduced through the input side (205), the surge voltage may be supplied to the first switching element (Q1) or the first impedance element (240).

[0114] A second impedance element (250) may be connected between the first node (N11) and the second power line (203). The second impedance element (250) may be connected in parallel with the second switching element (Q2). When a surge voltage is introduced through the input side (205), the surge voltage may be supplied to the second switching element (Q2) or the second impedance element (250).

[0115] 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 capacitor may block DC voltage and pass AC voltage. The capacitor may pass DC voltage as well as AC voltage. For example, when a surge voltage, which is an AC voltage, is input through the input side (205), the surge voltage may be supplied to the first node (N11) through the first impedance element (240) or the second impedance element (250). For example, when an input side voltage (VDC), which is a DC voltage, is input through the input side (205), the input side voltage (VDC) cannot be supplied to the first node (N11) through the first impedance element (240) or the second impedance element (250).

[0116] 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 first node (N11). The distributed voltage (Va) may be a detection voltage of the voltage detection circuit (235). 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 hundreds of V.

[0117] The protection circuit (260) can protect the constant voltage 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 first node (N11). Although the distributed voltage (Va) is smaller than the surge voltage, it can still be large enough to damage the constant voltage source (270), the detection circuit (280), the driving unit (220), etc.

[0118] That is, when a surge voltage is introduced through the input side (205), the voltage (Va) distributed from the surge voltage, i.e., the voltage (Va) of the first node (N11), is greater than the voltage (Vb) of the second node (N21), so that a current (I2) may flow from the first node (N11) to the second node (N21) in the second impedance element (250). The constant voltage source (270), the detection circuit (280), the driving unit (220), etc. may be damaged by this current (I2). The voltage (Va) of the first node (N11) may be a detection voltage detected by the voltage detection circuit (235), and the voltage (Vb) of the second node (N21) may be a constant voltage (Vref) output from the constant voltage source (270).

[0119] To solve this problem, a protection circuit (260) may be provided. The protection circuit (260) may be connected between the first node (N11) and the second node (N21). The protection circuit (260) may prevent damage to the constant voltage source (270), the detection circuit (280), the driving unit (220), etc. by preventing the current (I2) from flowing from the first node (N11) to the second node (N21). The detailed configuration of the protection circuit (260) will be described later.

[0120] A constant voltage source (270) may be connected to a second node (N21). The constant voltage source (270) may supply a constant voltage to the second node (N21). The constant voltage source (270) and the detection circuit (280) may be commonly connected to the second node (N21). The second node (N21) may be an output terminal of the constant voltage source (270) or may be connected to an output terminal. The second node (N21) may be a non-inverting (+) terminal of the detection circuit (280) or may be connected to a non-inverting (+) terminal.

[0121] A constant voltage source (270) is connected to the driving unit (220) and can receive power voltage from the driving unit (220). The constant voltage source (270) can output a constant voltage (Vref) using the voltage supplied from the driving unit (220).

[0122] Although the constant voltage source (270) is provided separately from the driving unit (220) in the drawing, it may be included in the driving unit (220). The constant voltage source (270) can provide a constant voltage (Vref). The constant voltage (Vref) can be supplied to the protection circuit (260) and the detection circuit (280) through the second node (N21). The detailed configuration of the constant voltage source (270) will be described later.

[0123] The detection circuit (280) can be connected to the first node (N11) and the second node (N21). The detection circuit (280) can include, for example, an amplifier, but is not limited thereto. For example, the non-inverting (+) terminal of the amplifier can be connected to the second node (N21), and the inverting (-) terminal of the amplifier can be connected to the first node (N11). In this case, the voltage (Vb) of the second node (N21), i.e., the positive voltage (Vref), can be supplied to the non-inverting (+) terminal of the amplifier, and the voltage (Va) of the first node (N11) can be supplied to the inverting (-) terminal of the amplifier. As described above, the positive voltage (Vref) has a constant value, whereas the voltage (Va) of the first node (N11), i.e., the detection voltage, can change according to a change in the voltage input to the input side (205). Accordingly, the difference between the voltage at the non-inverting (+) terminal of the amplifier and the voltage at the inverting (-) terminal of the amplifier can be changed. As the voltage (Va) of the first node (N11) increases, the difference between the voltage at the non-inverting (+) terminal of the amplifier and the voltage at the inverting (-) terminal of the amplifier can increase.

[0124] For example, when the input side voltage (VDC) is input through the input side (205), the voltage (Va) of the first node (N11) may be smaller than the voltage (Vb) of the second node (N21), i.e., the constant voltage (Vref). For example, when a surge voltage is input through the input side (205), the voltage (Va) of the first node (N11) may increase and be larger than the voltage (Vb) of the second node (N21), i.e., the constant voltage (Vref).

[0125] The detection circuit (280) can output a comparison result, i.e., a difference value, between the voltage of the non-inverting (+) terminal of the amplifier and the voltage of the inverting (-) terminal of the amplifier. In this case, the signal detection circuit (230) can obtain an abnormal control signal by using the difference value between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11). The abnormal control signal may be a signal to block a surge voltage so as not to damage the circuit elements described above. The signal detection circuit (230) can transmit the abnormal control signal to the driving unit (220).

[0126] The signal detection circuit (230) can output an abnormal control signal to the driving unit (220) when the voltage (Va) of the first node (N11) increases due to the surge voltage and matches the voltage (Vb) of the second node (N21), i.e., the constant voltage (Vref), i.e., when the difference value is 0.

[0127] The driving unit (220) can output an abnormal driving signal to drive the switching circuit (210) in response to the abnormal control signal. That is, the driving unit (220) can output an abnormal driving 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 currently in an on state, the driving unit (220) can turn off the first switching element (Q1) in the on state according to the abnormal driving signal. For example, when the second switching element (Q2) is currently in an off state, the driving unit (220) can continuously maintain the off state of the second switching element (Q2) according to the abnormal driving signal. Therefore, since the surge voltage is not supplied into the switching circuit (210), damage to circuit elements such as the driving unit can be prevented.

[0128] Meanwhile, when the surge voltage is reduced and extinguished, the voltage (Va) of the first node (N11) may be reduced. The signal detection circuit (230) may obtain a recovery control signal when the voltage (Va) of the first node (N11) is lower than the voltage (Vb) of the second node (N21). The driving unit (220) may turn on the first switching element (Q1) in the off state again according to the recovery control signal. The driving unit (220) may maintain the off state of the second switching element (Q2) according to the recovery control signal.

[0129] For example, the ideal control signal may be “1” and the return control signal may be “0”, but this is not limited thereto. In Fig. 4, I1 may be the current flowing in the first impedance element (240).

[0130] Meanwhile, the protection circuit (260) can have various modification examples as shown in FIGS. 6a to 6c.

[0131] As illustrated in Fig. 6a, the protection circuit (260) may include a reverse voltage prevention element (301) connected to a first node (N11). 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 first node (N11), so that reverse current does not flow from the first node (N11) to the second node (N21).

[0132] When a surge voltage flows in through the input side (205), the voltage (Va) of the first node (N11) distributed by the surge voltage may be greater than the voltage (Vb) of the second node (N21). The reverse voltage prevention element (301) of the embodiment can protect the constant voltage source (270), the detection circuit (280), the driving unit (220), etc. by preventing current from flowing from the first node (N11) to the second node (N21).

[0133] The protection circuit (260) may include a voltage sensing element (302). The voltage sensing element (302) may be connected between the second node (N21) and the reverse voltage prevention element (301).

[0134] The voltage sensing element (302) may include an impedance element, such as a resistor. The resistor may have a predetermined resistance value.

[0135] During normal or abnormal operation, the voltage (Va) of the first node (N11) changes, and the voltage (Vb) of the second node (N21), i.e., the constant voltage (Vref), can be fixed. When the input side voltage (VDC) is input to the input side (205), normal operation can be performed. When a surge voltage is input to the input side (205), abnormal operation can be performed. The voltage (Va) of the first node (N11) can vary depending on the input side voltage (VDC) or the surge voltage.

[0136] The voltage of the protection circuit (260) can be expressed by mathematical expression 1.

[0137] [Mathematical Formula 1]

[0138] V2 = Vb - Va

[0139] V2 may be the voltage of the protection circuit (260), Vb may be the voltage of the second node (N21), and Va may be the voltage of the first node (N11).

[0140] The voltage (Vb) of the second node (N21) is equal to the constant voltage (Vref), so it can have a constant voltage. The voltage (Va) of the first node (N11) can change depending on the voltage input through the input side (205).

[0141] As shown in mathematical expression 1, as the voltage (Va) of the first node (N11) increases, the voltage (V2) of the protection circuit (260) may decrease. That is, as shown in FIG. 5b, when a surge voltage occurs, the voltage (Va) of the first node (N11) increases, and thus the voltage (V2) of the protection circuit (260) may decrease.

[0142] The current flowing in the protection circuit (260) can be expressed by mathematical expression 2.

[0143] [Equation 2]

[0144] I2 = (Vb-Va) / Z3

[0145] I2 is the current flowing in the protection circuit (260), and Z3 may be the value of the impedance element included in the protection circuit (260).

[0146] As shown in mathematical expression 2, as the voltage (Va) of the first node (N11) increases, the current (I2) flowing in the protection circuit (260) may decrease. That is, as shown in FIG. 5a, when a surge voltage occurs, since the voltage (Va) of the first node (N11) increases, the current (I2) flowing in the protection circuit (260) may decrease.

[0147] Meanwhile, when the voltage (Va) of the first node (N11) is a distribution voltage of the input side voltage (VDC), the voltage (Vb) of the second node (N21) is greater than the voltage (Va) of the first node (N11), so that current (I2) can flow from the second node (N21) to the first node (N11) through the protection circuit (260).

[0148] When the voltage (Va) of the first node (N11) is the distribution voltage of the surge voltage, since the voltage (Va) of the first node (N11) is greater than the voltage (Vb) of the second node (N21), a current (I2) may flow from the first node (N11) to the second node (N21) in the protection circuit (260). However, according to an embodiment, the current (I2) flowing from the first node (N11) to the second node (N21) is blocked by the reverse voltage prevention element (301) provided in the protection circuit (260), so that the constant voltage source (270), the detection circuit (280), the driving unit (220), etc. may be protected. In the embodiment, the signal detection circuit (230) may output an abnormal control signal to the driving unit (220) by using the difference value between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11). In an embodiment, the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11) may be equal to the voltage (V2) of the protection circuit (260). In an embodiment, the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11) may be equal to the difference between the voltage of the non-inverting (+) terminal and the voltage of the inverting (-) terminal of the amplifier of the detection circuit (280).

[0149] As illustrated in Fig. 5c, when a surge voltage is applied, the voltage (Va) of the first node (N11) may increase. In this case, since the voltage (Vb) of the second node (N21), i.e., the constant voltage (Vref), is constant, the difference between the voltage (V2) of the protection circuit (260), i.e., the voltage (Vb) of the second node (N21), and the voltage (Va) of the first node (N11) may decrease. When the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11) becomes 0, the difference between the voltage of the non-inverting (+) terminal and the voltage of the inverting (-) terminal of the amplifier also becomes 0, so the signal detection circuit (230) can output an abnormal control signal to the driving unit (220).

[0150] As described above, the voltage (Va) of the first node (N11) may be a DC voltage or a voltage to which a surge voltage is distributed through the input side (205). While the voltage (Va) of the first node (N11) may be changed, the voltage (Vb) of the second node (N21) may be fixed.

[0151] As an example, the voltage (Va) of the first node (N11) distributed by the DC voltage may be less than the voltage (Vb) of the second node (N21), i.e., the constant voltage (Vref).

[0152] As another example, when a surge voltage is introduced through the input side (205), the voltage (Va) of the first node (N11) may become greater than the voltage (Vb) of the second node (N21). The detection circuit (280) may monitor the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11). The signal detection circuit (230) may monitor the detection circuit (280) and output an abnormal control signal to the driving unit (220) to protect at least one circuit element when the voltage (Va) of the first node (N11) increases and matches the voltage (Vb) of the second node (N21).

[0153] Meanwhile, as illustrated in FIG. 6b, the protection circuit (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 a first node (N11) and a second node (N21). 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.

[0154] Since the reverse voltage prevention element (301) and the voltage sensing element (302) are illustrated in Fig. 6a, further description is omitted.

[0155] The DC voltage blocking element (303) is connected between the voltage sensing element (302) and the second node (N21) and can block the DC voltage among the voltages (Va) of the first node (N11).

[0156] As illustrated in FIG. 6c, the protection circuit (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 a first node (N11) and a second node (N21). For example, the frequency filter element (304) may be connected to the second node (N21) and connected in parallel with the voltage sensing element (302).

[0157] Since the reverse voltage prevention element (301) and the voltage sensing element (302) are illustrated in Fig. 6a, further description is omitted.

[0158] The frequency filter element (304) can selectively supply a voltage of a specific frequency band among the voltages (Va) of the first node (N11) to the second node (N21).

[0159] The DC voltage blocking element (303) or the frequency filter element (304) is a component for removing noise, and a voltage with noise removed by the DC voltage blocking element (303) or the frequency filter element (304) can be generated at the second node (N21).

[0160] Meanwhile, the constant voltage source (270) may include a voltage generation circuit (330), a constant voltage generation circuit (330), a voltage regulator (340), etc., as illustrated in FIG. 7. FIG. 7 is an example, and various modifications of the constant voltage source (270) are possible.

[0161] The voltage generation circuit (330) can generate a voltage used to generate a constant voltage (Vref). The voltage generation circuit (330) can generate a predetermined voltage using a power voltage provided from the driving unit (220). The constant voltage generation circuit (330) includes two transistors (331, 333) and one resistor (332), but is not limited thereto. 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 (Vref) 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). The constant voltage (Vref) may be generated by the resistor (332) and the diode-type transistor (333). The voltage regulator (340) can adjust the size of the constant voltage (Vref) output from the node (N31).

[0162] Hereinafter, the operation of the abnormality detection blocking device according to the embodiment will be described in detail with reference to FIG. 4 and FIG. 8a to FIG. 8c.

[0163] Referring to FIG. 4 and FIG. 8a to FIG. 8c, 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).

[0164] The operation of the normal section (TNO) has been described above, so redundant explanation is omitted.

[0165] 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), etc. The first section (ST1) may be a section in which a surge voltage is introduced and an abnormal control signal for detecting an abnormal signal is obtained. The second section (ST2) may be a section in which the surge voltage is blocked based on the abnormal control signal. The third section (ST3) may be a section in which normal operation is restored and operation is performed.

[0166] <Section 1 (ST1)>

[0167] As described above, the first switching element (Q1) may be turned on and the second switching element (Q2) may be turned off during the normal period (TNO). Alternatively, the first switching element (Q1) may be turned off and the second switching element (Q2) may be turned on during the normal period (TNO).

[0168] 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.

[0169] 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 first node (N11). As the surge voltage increases during the first section (ST1), the voltage (Va) of the first node (N11) may increase. The voltage (Va) of the first node (N11) and the voltage (Vb) of the second node (N21) may be supplied to the detection circuit (280). While the voltage (Vb) of the second node (N21) is constant as a voltage (Vref), the voltage (Va) of the first node (N11) increases, so that the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11) may decrease.

[0170] <Second Section (ST2)>

[0171] The detection circuit (280) can monitor the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11).

[0172] When the voltage (Va) of the first node (N11) increases and matches the voltage (Vb) of the second node (N21), the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11) may become 0. In this case, the signal detection circuit (230) may output an abnormal control signal to the driving unit (220).

[0173] The driving unit (220) can block the surge voltage based on the abnormal control signal. That is, the driving unit (220) can turn off the first switching element (Q1) that is currently on according to the abnormal control signal. The driving unit (220) can maintain the off state of the second switching element (Q2) according to the abnormal control 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, the generation of an avalanche current due to the breakdown voltage of the second switching element (Q2) is prevented, so that damage to not only the switching circuit (210) but also the signal detection circuit (230) connected to the switching circuit (210) or the driving unit can be prevented.

[0174] <Section 3 (ST3)>

[0175] As time passes, the surge voltage may decrease and disappear. As the surge voltage disappears, the voltage (Va) of the first node (N11) decreases, so the voltage (Va) of the first node (N11) becomes smaller than the voltage (Vb) of the second node (N21), and the difference between the voltage (Vb) of the second node (N21) and the voltage (Va) of the first node (N11) may increase.

[0176] When the voltage (Va) of the first node (N11) decreases and becomes lower than the voltage (Vb) of the second node (N21), the detection circuit (280) can obtain a return control signal. The return control signal can be transmitted to the driving unit (220).

[0177] When the driving unit (220) receives a return control signal, it can turn on the first switching element (Q1) that is in an off state during the third period (ST3). The driving unit (220) can maintain the off state of the second switching element (Q2).

[0178]

[0179] [Example 3]

[0180] Fig. 9 is a circuit diagram illustrating an abnormal signal blocking device and a power conversion device according to the third embodiment.

[0181] The third embodiment is identical to the second embodiment except for the current measurement circuit (290). In the third embodiment, components having the same functions as those in the second embodiment are given the same drawing reference numerals and detailed descriptions are omitted.

[0182] Referring to FIG. 9, the power conversion device (202) according to the third embodiment may include a switching circuit (210), an abnormal signal blocking device (207), etc.

[0183] The abnormal signal blocking device (207) may include a driving unit (220), a signal detection circuit (230), etc.

[0184] The signal detection circuit (230) may include a first impedance element (240), a second impedance element (250), a protection circuit (260), a constant voltage source (270), a current measurement circuit (290), etc.

[0185] The signal detection circuit (230) can obtain an abnormal control signal by using the current (I2) flowing in the protection circuit (260).

[0186] The current measurement circuit (290) is connected to the first node (N11) and the second node (N21) and can measure the current (I2) flowing in the protection circuit (260). The signal detection circuit (230) can obtain an abnormal control signal using the measured current (I2). The abnormal control signal can be provided to the driving unit (220).

[0187] As described above, the voltage (Va) of the first node (N11) changes according to the voltage input through the input side (205), whereas the voltage (Vb) of the second node (N21) can be fixed as a constant voltage (Vref). Accordingly, the voltage (Vb) of the second node (N21) can be less than, equal to, or greater than the voltage (Va) of the first node (N11) depending on the increase or decrease in the voltage (Vb) of the second node (N21).

[0188] For example, when the input side voltage (VDC) is input through the input side (205), the voltage (Va) of the first node (N11), which is a distribution voltage of the input side voltage (VDC), may be lower than the voltage (Vb) of the second node (N21). Accordingly, the current (I2) may flow from the second node (N21) to the first node (N11) through the protection circuit (260).

[0189] As another example, when a surge voltage is introduced through the input side (205), the voltage (Va) of the first node (N11), which is a distribution voltage of the surge voltage, may increase and be greater than the voltage (Vb) of the second node (N21). Accordingly, the current (I2) may flow from the first node (N11) to the second node (N21) in the protection circuit (260). However, in an embodiment, the protection circuit (260) may include a reverse voltage prevention element (301 of FIGS. 6A to 6C). The reverse voltage prevention element (301) may prevent the current (I2) from flowing from the first node (N11) to the second node (N21).

[0190] According to an embodiment, the signal detection circuit (230) can obtain an abnormal control signal using the current (I2) measured for the protection circuit (260). For example, when the current (I2) measured in the protection circuit (260) is 0, the abnormal control signal can be output to the driving unit (220). The driving unit (220) can turn off the first switching element (Q1) currently in the on state according to the abnormal control signal. The driving unit (220) can maintain the second switching element (Q2) currently in the off state according to the abnormal control signal.

[0191] As the surge voltage decreases and dissipates, the voltage (Va) of the first node (N11) may decrease. When the voltage (Va) of the first node (N11) decreases and becomes smaller than the voltage (Vb) of the second node (N21), the current (I2) may flow from the first node (N11) to the second node (N21). In this case, the signal detection circuit (230) may obtain a return control signal and output the obtained return control signal to the driving unit (220). The driving unit (220) may turn on the first switching element (Q1) in the off state according to the return control signal. The driving unit (220) may turn off the second switching element (Q2) in the off state according to the return control signal.

[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 outputting a detection voltage according to a voltage input from an input side between the first power line and the second power line; A constant voltage source connected to the second node and supplying constant voltage; and A detection circuit connected to the first node and the second node, and configured to detect an abnormal signal; Anomaly signal blocking device.

2. In paragraph 1, The above detection circuit comprises an amplifier having a non-inverting terminal connected to the second node and an inverting terminal connected to the first node. 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. Anomaly signal blocking device.

4. In paragraph 3, The above driving part, If an abnormal signal is detected based on the comparison result between the above-mentioned constant voltage and the above-mentioned detection voltage, the switching element currently in the on state among the first switching element and the second switching element is turned off. Anomaly signal blocking device.

5. In paragraph 4, The above driving part, When it is detected that the abnormal signal has disappeared based on the comparison result between the above-mentioned constant voltage and the above-mentioned detection voltage, the switching element in the off state is turned on again. Anomaly signal blocking device.

6. In paragraph 1, Further comprising a protection circuit connected between the first node and the second node to block abnormal voltage; Anomaly signal blocking device.

7. In paragraph 1, The above protection circuit, including a reverse voltage prevention element connected to the first node; Anomaly signal blocking device.

8. In paragraph 7, The above protection circuit, further comprising a voltage sensing element connected to the reverse voltage prevention element; Anomaly signal blocking device.

9. In paragraph 8, The above protection circuit, Further comprising a DC voltage blocking element connected to the voltage sensing element; Anomaly signal blocking device.

10. In paragraph 8, The above protection circuit, Further comprising a frequency filter element connected to the above reverse voltage prevention element; Anomaly signal blocking device.

11. 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 outputting a detection voltage according to a voltage input from an input side between the first power line and the second power line; A constant voltage source connected to the second node and supplying constant voltage; and A detection circuit connected to the first node and the second node, and configured to detect an abnormal signal; Power conversion device.

12. In paragraph 11, 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, If an abnormal signal is detected based on the comparison result between the above-mentioned constant voltage and the above-mentioned detection voltage, the switching element currently in the on state among the first switching element and the second switching element is turned off. Power conversion device.

13. In paragraph 12, Further comprising a protection circuit connected between the first node and the second node to block abnormal voltage; Power conversion device.

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