A dual-function detection circuit and protection circuit for power devices

Abstract

This invention discloses a dual-function detection circuit and protection circuit for power devices. When the power device is in the ON state, the first switch circuit of the short-circuit detection circuit is locked, and the second switch circuit of the overvoltage detection circuit is unlocked. The detection module determines whether the power device is short-circuited by detecting the voltage of the short-circuit detection circuit. When the power device is in the OFF state, the first switch circuit of the short-circuit detection circuit is unlocked, and the second switch circuit of the overvoltage detection circuit is locked. The detection module determines whether the power device is over-voltage by detecting the voltage of the overvoltage detection circuit. This invention achieves dual-function short-circuit and overvoltage detection protection through only one loop by setting the short-circuit detection circuit and overvoltage detection circuit in corresponding states for different power device states. The circuit structure is simple and easy to implement.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, specifically to a dual-function detection circuit and protection circuit for power devices. Background Technology

[0002] Series connection of power devices is the most direct technical means to improve the capacity and voltage level of power electronic converters. It simplifies the main circuit structure of the converter, significantly reduces the number of devices, lowers control complexity and DC capacitor energy, thereby greatly improving the power density and technical economy of high-voltage, high-capacity power electronic devices. It has broad application prospects in ultra-high voltage and extra-high voltage flexible AC transmission, flexible DC transmission, and renewable energy grid connection. However, due to differences in the internal parameters and turn-on / turn-off drive pulse times of each series-connected power device, dynamic and steady-state voltage unevenness will occur between the series-connected devices. In severe cases, this can lead to overvoltage and damage to the equipment. Therefore, overvoltage detection and protection of power devices is very important. However, traditional power device drive circuits only have short-circuit detection and protection functions, but lack overvoltage detection and protection. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect of traditional drive circuits in the prior art that lack overvoltage detection and protection, thereby providing a dual-function detection circuit and protection circuit for power devices.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] In a first aspect, embodiments of the present invention provide a dual-function detection circuit for a power device, comprising: a short-circuit detection circuit, an overvoltage detection circuit, a control module, and a detection module; both the short-circuit detection circuit and the overvoltage detection circuit are connected to the power device, the control module, and the detection module; when the power device is in a conducting state, the first switch circuit controlling the short-circuit detection circuit is locked, the second switch circuit controlling the overvoltage detection circuit is unlocked, and the detection module determines whether the power device is short-circuited by detecting the voltage of the short-circuit detection circuit; when the power device is in a turning-off state, the first switch circuit controlling the short-circuit detection circuit is unlocked, the second switch circuit controlling the overvoltage detection circuit is locked, and the detection module determines whether the power device is over-voltage by detecting the voltage of the overvoltage detection circuit.

[0006] In one embodiment, the dual-function detection circuit for the power device further includes a voltage divider circuit; the power device is connected to both the short-circuit detection circuit and the overvoltage detection circuit via the voltage divider circuit.

[0007] In one embodiment, the voltage divider circuit includes: a resistor branch consisting of multiple series-connected voltage divider resistors and a capacitor branch consisting of multiple series-connected voltage divider capacitors; the resistor branch is connected to the power device and the short-circuit detection circuit respectively; and the capacitor branch is connected to the power device and the ground terminal respectively.

[0008] In one embodiment, the power device dual-function detection circuit further includes: a voltage regulator circuit; the voltage divider circuit is connected to the overvoltage detection circuit through the voltage regulator circuit.

[0009] In one embodiment, the voltage regulator circuit includes a plurality of Zener diodes connected in series.

[0010] In one embodiment, the short-circuit detection circuit further includes: a first energy storage circuit; the first energy storage circuit is connected to a voltage divider circuit and a ground terminal respectively; a first switching circuit is connected to the first energy storage circuit, a control module and a ground terminal respectively; when the power device is in the off state, the control module controls the first switching circuit to be turned on; when the power device is in the on state, the control module controls the first switching circuit to be turned off, and the detection module determines whether the power device is short-circuited by detecting the voltage of the first energy storage circuit.

[0011] In one embodiment, the first switching circuit includes: a first pull-up resistor and a first controllable switch; a first terminal of the first controllable switch is connected to a first energy storage circuit through the first pull-up resistor, a second terminal of the first controllable switch is connected to a ground terminal, and a control terminal of the first controllable switch is connected to a control module; when the power device is in the off state, the control module controls the first controllable switch to be turned on; when the power device is in the on state, the control module controls the first controllable switch to be turned off.

[0012] In one embodiment, the first energy storage circuit includes: a first grounding resistor, a short-circuit detection resistor, and a short-circuit detection capacitor; the first end of the short-circuit detection resistor is connected to a voltage divider circuit, and the first end of the short-circuit detection resistor is also grounded through the first grounding resistor; the second end of the short-circuit detection resistor is connected to a first switching circuit, and the second end of the short-circuit detection resistor is also grounded through the short-circuit detection capacitor.

[0013] In one embodiment, the overvoltage detection circuit further includes: a second energy storage circuit; the second energy storage circuit is connected to a voltage regulator circuit and a ground terminal respectively; a second switching circuit is connected to the second energy storage circuit, a control module, and a ground terminal respectively; when the power device is in the on state, the control module controls the second switching circuit to be on; when the power device is in the off state, the control module controls the second switching circuit to be off, and the detection module determines whether the power device is overvoltage by detecting the voltage of the second energy storage circuit.

[0014] In one embodiment, the second switching circuit includes: a second pull-up resistor and a second controllable switch; the first terminal of the second controllable switch is connected to the second energy storage circuit through the second pull-up resistor, the second terminal of the second controllable switch is connected to the ground terminal, and the control terminal of the second controllable switch is connected to the control module; when the power device is in the off state, the control module controls the second controllable switch to be off; when the power device is in the on state, the control module controls the second controllable switch to be on.

[0015] In one embodiment, the second energy storage circuit includes: a second grounding resistor, an overvoltage detection resistor, and an overvoltage detection capacitor; the first end of the overvoltage detection resistor is connected to the voltage regulator circuit, and the first end of the overvoltage detection resistor is also grounded through the second grounding resistor; the second end of the overvoltage detection resistor is connected to the second switching circuit, and the second end of the overvoltage detection resistor is also grounded through the overvoltage detection capacitor.

[0016] Secondly, embodiments of the present invention provide a protection circuit for a power device, comprising: a dual-function detection circuit and a protection circuit body; the protection circuit body is connected to the power device and the dual-function detection circuit respectively; when the dual-function detection circuit determines that the power device is short-circuited or over-voltage, the protection circuit body executes a corresponding protection mechanism.

[0017] The technical solution of this invention has the following advantages:

[0018] The present invention provides a dual-function detection circuit for power devices, comprising a short-circuit detection circuit, an overvoltage detection circuit, a control module, and a detection module. Both the short-circuit detection circuit and the overvoltage detection circuit are connected to the power device, the control module, and the detection module. When the power device is in the ON state, the first switch circuit of the short-circuit detection circuit is locked, and the second switch circuit of the overvoltage detection circuit is unlocked. The detection module determines whether the power device is short-circuited by detecting the voltage of the short-circuit detection circuit. When the power device is in the OFF state, the first switch circuit of the short-circuit detection circuit is unlocked, and the second switch circuit of the overvoltage detection circuit is locked. The detection module determines whether the power device is overvoltaged by detecting the voltage of the overvoltage detection circuit. This invention achieves dual-function short-circuit and overvoltage detection protection through a single loop by setting the short-circuit detection circuit and overvoltage detection circuit to corresponding states for different power device states. The circuit structure is simple and easy to implement. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A composition diagram of a specific example of a dual-function detection circuit provided in an embodiment of the present invention;

[0021] Figure 2 A composition diagram of another specific example of the dual-function detection circuit provided in an embodiment of the present invention;

[0022] Figure 3A detailed circuit structure diagram of the dual-function detection circuit provided in the embodiments of the present invention;

[0023] Figure 4 A composition diagram of another specific example of the dual-function detection circuit provided in an embodiment of the present invention;

[0024] Figure 5 This is a composition diagram of another specific example of a dual-function detection circuit provided in an embodiment of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Example 1

[0030] This invention provides a dual-function detection circuit for power devices, such as... Figure 1 As shown, it includes: a short-circuit detection circuit 1, an overvoltage detection circuit 2, a control module 3, and a detection module 6.

[0031] Furthermore, Figure 1In the circuit, both the short-circuit detection circuit 1 and the overvoltage detection circuit 2 are connected to the power device (T1), the control module 3, and the detection module 6.

[0032] It should be noted that, Figure 1 The power devices mentioned are exemplified by IGBTs, but this is only used as an example and is not a limitation.

[0033] Furthermore, when the power device is in the on state, the first switch circuit of the short circuit detection circuit 1 is locked, the second switch circuit of the overvoltage detection circuit 2 is unlocked, and the detection module 6 determines whether the power device is short-circuited by detecting the voltage of the short circuit detection circuit 1.

[0034] Furthermore, when the power device is in the off state, the first switch circuit of the short circuit detection circuit 1 is unlocked, the second switch circuit of the overvoltage detection circuit 2 is locked, and the detection module 6 determines whether the power device is overvoltage by detecting the voltage of the overvoltage detection circuit 2.

[0035] Specifically, as can be seen from the working principle of power devices, short-circuit faults only occur during the power device's conduction period, while overvoltage faults only occur during the power device's turn-off period. Therefore, in order to achieve accurate detection of short-circuit faults and overvoltage faults, this embodiment controls the operating state of the first switching circuit of the short-circuit detection circuit 1 and the second switching circuit of the overvoltage detection circuit 2, so that only short-circuit fault detection is performed during the power device's conduction period, and only overvoltage fault detection is performed during the power device's turn-off period.

[0036] Specifically, such as Figure 1 As shown in the embodiment of the present invention, during the power device conduction period, the second switch circuit of the overvoltage detection circuit 2 is unlocked and the first switch circuit of the short circuit detection circuit 1 is locked, so only the short circuit detection circuit 1 performs the detection work at this time; during the power device turn-off period, the second switch circuit of the overvoltage detection circuit 2 is locked and the first switch circuit of the short circuit detection circuit 1 is unlocked, so only the overvoltage detection circuit 2 performs the detection work at this time.

[0037] It should be noted that, in this embodiment of the invention, the detection module 6 determines whether the power device is short-circuited by monitoring the voltage of the short-circuit detection circuit 1 (which can actually be the voltage of the first energy storage circuit of the short-circuit detection circuit), and determines whether the power device is over-voltage by monitoring the voltage of the overvoltage detection circuit 2 (which can actually be the voltage of the second energy storage circuit of the overvoltage detection circuit). However, other electrical parameters can still be used to determine whether there is a short circuit or overvoltage, which will not be elaborated here.

[0038] Furthermore, when the detection module 6 determines that the power device is short-circuited or over-voltage, it can report the fault information.

[0039] It should be noted that the control module 3 in this embodiment of the invention may include a driving circuit for the power device, which drives the power device to turn on and off.

[0040] In one specific embodiment, such as Figure 2 As shown, the dual-function detection circuit for power devices also includes: voltage divider circuit 4.

[0041] Furthermore, such as Figure 2 As shown, the power device is connected to the short-circuit detection circuit 1 and the overvoltage detection circuit 2 respectively through the voltage divider circuit 4.

[0042] Specifically, due to the electrical characteristics of the internal components of the short-circuit detection circuit 1 and the overvoltage detection circuit 2, a voltage divider circuit 4 can be set up as needed to realize short-circuit detection and overvoltage detection based on the voltage divider voltage.

[0043] In one specific embodiment, the voltage divider circuit 4 includes:

[0044] A resistor branch consisting of multiple series-connected voltage-dividing resistors and a capacitor branch consisting of multiple series-connected voltage-dividing capacitors; the resistor branch is connected to the power device and the short-circuit detection circuit 1 respectively; the capacitor branch is connected to the power device and the ground terminal respectively.

[0045] Specifically, in this embodiment of the invention, a voltage divider circuit 4 is formed by connecting multiple voltage divider units in series, and each voltage divider power supply is composed of a voltage divider resistor and a voltage divider capacitor.

[0046] Optionally, such as Figure 3 As shown, the voltage divider resistors R1 to Rn are connected in series to form a resistor branch, and the voltage divider capacitors C1 to Cp are connected in series to form a capacitor branch.

[0047] It should be noted that, Figure 3 Other structures can also be shown, and no restrictions are imposed here.

[0048] In one specific embodiment, such as Figure 4 As shown, the dual-function detection circuit for power devices also includes: a voltage regulator circuit 5; and a voltage divider circuit 4 connected to the overvoltage detection circuit 2 via the voltage regulator circuit 5.

[0049] Specifically, voltage instability may cause overvoltage in power devices. Therefore, in order to accurately detect this, this embodiment of the invention includes a voltage regulator circuit 5 to maintain a constant voltage. Furthermore, to prevent damage to the overvoltage detection circuit 2 caused by overvoltage, the voltage regulator circuit 5 can also reduce the overvoltage before making a judgment.

[0050] In one specific embodiment, such as Figure 3 As shown, the voltage regulator circuit 5 includes a plurality of Zener diodes (D1 to Dn) connected in series.

[0051] It should be noted that since Zener diodes are greatly affected by temperature, and Zener diodes of different voltage levels have different temperature characteristics, they can be matched according to the temperature characteristics of Zener diodes of different voltage levels to achieve an overall Zener diode voltage that does not change with temperature.

[0052] In one specific embodiment, such as Figure 5 As shown, the short circuit detection circuit 1 includes: a first switching circuit 11 and a first energy storage circuit 12; the first energy storage circuit 12 is connected to the voltage divider circuit 4 and the ground terminal respectively; the first switching circuit 11 is connected to the first energy storage circuit 12, the control module 3 and the ground terminal respectively.

[0053] Furthermore, when the power device is in the off state, the control module 3 controls the first switching circuit 11 to be turned on; when the power device is in the on state, the control module 3 controls the first switching circuit 11 to be turned off, and the detection module 6 determines whether the power device is short-circuited by detecting the voltage of the first energy storage circuit 12.

[0054] Specifically, during the power device's off-state period, the control module 3 controls the first switching circuit 11 to turn on. At this time, current does not flow through the first energy storage circuit 12, and the first energy storage circuit 12 is not charged. During the power device's on-state period, the control module 3 controls the first switching circuit 11 to turn off. At this time, current flows through the first energy storage circuit 12, charging the first energy storage circuit 12. When the power device is short-circuited, the short-circuit current charges the first energy storage circuit 12. Therefore, the detection module 6 determines whether the power device is short-circuited by detecting the voltage of the first energy storage circuit 12. The determination method is not limited to the threshold comparison method.

[0055] In one specific embodiment, such as Figure 3 As shown, the first switching circuit 11 includes: a first pull-up resistor R U1 and the first controllable switch Q1; the first terminal of the first controllable switch Q1 is connected to the first pull-up resistor R. U1 It is connected to the first energy storage circuit 12, the second end of the first controllable switch Q1 is connected to the ground terminal, and the control terminal of the first controllable switch Q1 is connected to the control module 3.

[0056] Furthermore, when the power device is in the off state, the control module 3 controls the first controllable switch Q1 to turn on; when the power device is in the on state, the control module 3 controls the first controllable switch Q1 to turn off.

[0057] Specifically, when the power device is in the off state, the control module 3 controls the first controllable switch Q1 to be turned on, and the current of the power device flows through the first controllable switch Q1 and does not charge the first energy storage circuit 12; when the power device is in the on state, the control module 3 controls the first controllable switch Q1 to be turned off, and the current of the power device does not flow through the first controllable switch Q1 and does not charge the first energy storage circuit 12.

[0058] It should be noted that, Figure 3 The first controllable switch Q1 in this example uses an IGBT device, but other controllable switches are also possible and are not limited here.

[0059] In one specific embodiment, such as Figure 3 As shown, the first energy storage circuit 12 includes: a first grounding resistor R G1 Short-circuit detection resistor R div_SC and short-circuit detection capacitor C div_SC Short-circuit detection resistor R div_SC The first terminal is connected to voltage divider circuit 4, and short-circuit detection resistor R. div_SC The first end is also connected to the first grounding resistor R G1 Grounding, short circuit detection resistor R div_SC The second terminal is connected to the first switching circuit 11, and the short-circuit detection resistor R div_SC The second end is also grounded through a short-circuit detection capacitor.

[0060] Specifically, the energy storage component of the first energy storage circuit 12 is actually a short-circuit detection capacitor. When the power device is in the off state, the control module 3 controls the first switching circuit 11 to be turned on, and the current of the power device flows through the first controllable switch Q1 and does not charge the short-circuit detection capacitor. When the power device is in the on state, the control module 3 controls the first switching circuit 11 to be turned off, and the current of the power device does not flow through the first controllable switch Q1 and does not charge the short-circuit detection capacitor. Therefore, the short-circuit detection capacitor voltage is monitored to determine whether the power device is short-circuited.

[0061] based on Figure 3 The short-circuit detection circuit 1 shown in this embodiment of the invention has the following short-circuit detection principle:

[0062] Short-circuit faults only occur during the IGBT device T1's on-state. During the IGBT device T1's off-state, control module 3 controls the first controllable switch Q1 to be in the on-state, at which time the short-circuit detection capacitor C... div_SC It will not be charged, and there will be no false short-circuit fault alarms; during the IGBT device T1 turn-on period, the first controllable switch Q1 is turned off by the control module 3. If there is no short-circuit fault during the T1 turn-on period, the short-circuit detection capacitor C... div_SC No voltage; when a short circuit fault occurs during the turn-on period of T1, the short circuit detection capacitor C... div_SC It is being charged, therefore it can be detected by C. div_SC Voltage is used to determine whether a short circuit fault has occurred. By uploading the fault information, short circuit protection for devices can be achieved.

[0063] In one specific embodiment, such as Figure 5As shown, the overvoltage detection circuit 2 includes: a second switching circuit 21 and a second energy storage circuit 22; the second energy storage circuit 22 is connected to the voltage regulator circuit 5 and the ground terminal respectively; the second switching circuit 21 is connected to the second energy storage circuit 22, the control module 3 and the ground terminal respectively.

[0064] Furthermore, when the power device is in the off state, the control module 3 controls the second switching circuit 21 to turn off; when the power device is in the on state, the control module 3 controls the second switching circuit 21 to turn on, and the detection module 6 determines whether the power device is over-voltage by detecting the voltage of the second energy storage circuit 22.

[0065] Specifically, during the power device's off-state period, the control module 3 controls the second switching circuit 21 to turn off. At this time, current does not flow through the second switching circuit 21 but instead charges the second energy storage circuit 22. During the power device's on-state period, the control module 3 controls the second switching circuit 21 to turn on. At this time, current flows through the switching circuit but does not charge the second energy storage circuit 22. When the power device experiences overvoltage, the overvoltage charges the second energy storage circuit 22. Therefore, the detection module 6 determines whether the power device is overvoltage by detecting the voltage of the second energy storage circuit 22. The determination method is not limited to the threshold comparison method.

[0066] In one specific embodiment, such as Figure 3 As shown, the second switching circuit 21 includes: a second pull-up resistor R U2 and the second controllable switch Q2; the first terminal of the second controllable switch Q2 is connected to the second pull-up resistor R. U2 It is connected to the second energy storage circuit 22, the second terminal of the second controllable switch Q2 is connected to the ground terminal, and the control terminal of the second controllable switch Q2 is connected to the control module 3.

[0067] Furthermore, when the power device is in the off state, the control module 3 controls the second controllable switch Q2 to turn off; when the power device is in the on state, the control module 3 controls the second controllable switch Q2 to turn on.

[0068] Specifically, during the power device turn-off period, the control module 3 controls the second controllable switch Q2 to turn off. At this time, the current will not flow through the second switching circuit 21, but will charge the second energy storage circuit 22. During the power device turn-on period, the control module 3 controls the second controllable switch Q2 to turn on. At this time, the current flows through the switching circuit and will not charge the second energy storage circuit 22.

[0069] It should be noted that, Figure 3 The second controllable switch Q2 in this example uses an IGBT device, but other controllable switches are also possible and are not limited here.

[0070] In one specific embodiment, such as Figure 3As shown, the second energy storage circuit 22 includes: a second grounding resistor RG2 and an overvoltage detection resistor R. div_OV and overvoltage detection capacitor C div_OV Overvoltage detection resistor R div_OV The first terminal is connected to the voltage regulator circuit 5, and the overvoltage detection resistor R div_OV The first terminal is also grounded through the second grounding resistor RG2, and the overvoltage detection resistor R div_OV The second terminal is connected to the second switching circuit 21, and the overvoltage detection resistor R div_OV The second terminal also uses an overvoltage detection capacitor C div_OV Grounding.

[0071] Specifically, the energy storage component of the second energy storage circuit 22 is actually an overvoltage detection capacitor C. div_OV When the power device is in the off state, the control module 3 controls the second switching circuit 21 to turn off, and the current of the power device does not flow through the second switching circuit 21, which is the overvoltage detection capacitor C. div_OV Charging; when the power device is in the on state, the control module 3 controls the second switching circuit 21 to conduct, and the current of the power device flows through the second switching circuit 21 and the overvoltage detection capacitor C. div_OV Charging, therefore, by monitoring the overvoltage detection capacitor C div_OV Voltage is used to determine whether power devices are over-voltage.

[0072] based on Figure 3 The overvoltage detection circuit 2 shown in this embodiment of the invention has the following overvoltage detection principle:

[0073] Overvoltage faults only occur during the IGBT device T1 turn-off period. During the IGBT device T1 turn-on period, the control module 3 controls the second controllable switch Q2 to be in the on state, at which time the overvoltage detection capacitor C... div_SC It will not be charged, and there will be no false overvoltage fault reports; during the IGBT device T1 turn-off period, the second controllable switch Q2 is turned off by the control module 3. By selecting the Zener diodes D1 to Dn, the overvoltage detection capacitor C can be activated when there is no overvoltage fault during the T1 turn-off period. div_OV No voltage; if an overvoltage fault occurs during the T1 turn-off period, the overvoltage detection capacitor C... div_OV It is being charged, therefore it can be detected by C. div_OV The voltage is used to determine whether an overvoltage fault has occurred. By uploading the fault information, overvoltage protection for the device can be achieved.

[0074] Example 2

[0075] This invention provides a protection circuit for a power device, comprising: a dual-function detection circuit as described in Embodiment 1, and a protection circuit body; the protection circuit body is connected to the power device and the dual-function detection circuit respectively; when the dual-function detection circuit determines that the power device is short-circuited or over-voltage, the protection circuit body executes the corresponding protection mechanism.

[0076] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dual-function detection circuit for power devices, characterized in that, include: Short circuit detection circuit, overvoltage detection circuit, control module, detection module, voltage divider circuit and voltage regulator circuit; Both the short-circuit detection circuit and the overvoltage detection circuit are connected to the power device, the control module, and the detection module. When the power device is in the on state, the first switch circuit of the short circuit detection circuit is locked and the second switch circuit of the overvoltage detection circuit is unlocked. The detection module determines whether the power device is short-circuited by detecting the voltage of the short circuit detection circuit. When the power device is in the off state, the first switch circuit of the short circuit detection circuit is unlocked and the second switch circuit of the overvoltage detection circuit is locked. The detection module determines whether the power device is overvoltage by detecting the voltage of the overvoltage detection circuit. The power device is connected to the short-circuit detection circuit through the voltage divider circuit; The power device is connected to the overvoltage detection circuit through the voltage divider circuit, the voltage regulator circuit, and the overvoltage detection circuit. The short-circuit detection circuit includes: a first energy storage circuit; the first energy storage circuit is connected to the voltage divider circuit and the ground terminal respectively; a first switching circuit is connected to the first energy storage circuit, the control module and the ground terminal respectively; when the power device is in the off state, the control module controls the first switching circuit to be turned on; when the power device is in the on state, the control module controls the first switching circuit to be turned off, and the detection module determines whether the power device is short-circuited by detecting the voltage of the first energy storage circuit; The overvoltage detection circuit also includes: Second energy storage circuit; The second energy storage circuit is connected to the voltage regulator circuit and the ground terminal respectively; The second switching circuit is connected to the second energy storage circuit, the control module, and the grounding terminal, respectively. When the power device is in the ON state, the control module controls the second switching circuit to ON; when the power device is in the OFF state, the control module controls the second switching circuit to OFF, and the detection module determines whether the power device is over-voltage by detecting the voltage of the second energy storage circuit.

2. The dual-function detection circuit for power devices according to claim 1, characterized in that, The voltage divider circuit includes: A resistor branch consisting of multiple series-connected voltage-dividing resistors and a capacitor branch consisting of multiple series-connected voltage-dividing capacitors.

3. The dual-function detection circuit for power devices according to claim 1, characterized in that, The voltage regulator circuit includes: Multiple Zener diodes connected in series.

4. The dual-function detection circuit for power devices according to claim 1, characterized in that, The first switching circuit includes: First pull-up resistor and first controllable switch; The first terminal of the first controllable switch is connected to the first energy storage circuit through the first pull-up resistor, the second terminal of the first controllable switch is connected to the ground terminal, and the control terminal of the first controllable switch is connected to the control module. When the power device is in the off state, the control module controls the first controllable switch to be turned on; when the power device is in the on state, the control module controls the first controllable switch to be turned off.

5. The dual-function detection circuit for power devices according to claim 1, characterized in that, The first energy storage circuit includes: First grounding resistance, short-circuit detection resistor, and short-circuit detection capacitor; The first end of the short-circuit detection resistor is connected to the voltage divider circuit, and the first end of the short-circuit detection resistor is also grounded through the first grounding resistor. The second end of the short-circuit detection resistor is connected to the first switching circuit, and the second end of the short-circuit detection resistor is also grounded through the short-circuit detection capacitor.

6. The dual-function detection circuit for power devices according to claim 1, characterized in that, The second switching circuit includes: Second pull-up resistor and second controllable switch; The first terminal of the second controllable switch is connected to the second energy storage circuit through the second pull-up resistor, the second terminal of the second controllable switch is connected to the ground terminal, and the control terminal of the second controllable switch is connected to the control module. When the power device is in the off state, the control module controls the second controllable switch to turn off; when the power device is in the on state, the control module controls the second controllable switch to turn on.

7. The dual-function detection circuit for power devices according to claim 1, characterized in that, The second energy storage circuit includes: Second grounding resistor, overvoltage detection resistor and overvoltage detection capacitor; The first end of the overvoltage detection resistor is connected to the voltage regulator circuit, and the first end of the overvoltage detection resistor is also grounded through the second grounding resistor. The second end of the overvoltage detection resistor is connected to the second switching circuit, and the second end of the overvoltage detection resistor is also grounded through the overvoltage detection capacitor.

8. A protection circuit for a power device, characterized in that, include: The dual-function detection circuit and protection circuit body as described in any one of claims 1-7; The protection circuit body is connected to the power device and the dual-function detection circuit respectively; When the dual-function detection circuit determines that the power device is short-circuited or over-voltage, the protection circuit body executes the corresponding protection mechanism.

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