Latch protection circuit and switch protection system
By acquiring and comparing the switching equipment signals through a latching protection circuit, and continuously blocking the drive signal, the problem of overcurrent recurrence in the switching equipment after the fault disappears is solved, thus achieving equipment safety protection and reliability improvement.
Patent Information
- Application Number
- CN202423062160.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-12-11
AI Technical Summary
In the existing technology, even after the fault disappears when the current of the switching equipment is lower than the protection value, overcurrent may still occur again, leading to equipment damage, and there is a lack of an effective continuous protection mechanism.
A latching protection circuit is adopted. The sampling module collects the signal to be tested and generates a voltage signal. The judgment module performs threshold comparison. When there is an abnormality, the fault latching module continuously outputs a blocking signal. The output module controls the drive signal to block until a reset signal is received and the system returns to normal.
It enables fault latching of switching equipment, ensuring that the equipment stops working before the signal under test returns to normal, thus avoiding damage and improving the reliability and safety of the equipment.
Smart Images
Figure CN223729728U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of power electronics, and particularly relates to a latch protection circuit and a switching protection system. BACKGROUND
[0002] With the development of power electronics technology, the power level of power supply equipment is gradually improved, and the current level faced is also increased, and the overcurrent protection of the switching semiconductor becomes particularly important. At present, the common protection is post-overcurrent trigger protection, and the fault disappears when the current is lower than the protection value. However, at this time, the current is still at a large current value, and the switching tube may overcurrent again after the fault disappears, resulting in damage. CONTENT OF THE UTILITY MODEL
[0003] The present application aims to at least solve one of the technical problems in the prior art. To this end, the present application needs to provide a latch protection circuit and a switching protection system.
[0004] The latch protection circuit of the present application embodiment is used for protecting a switching device, and the latch protection circuit comprises:
[0005] a sampling module, configured to collect a to-be-tested signal output by the switching device and generate a voltage signal according to the to-be-tested signal;
[0006] a determination module, connected to the sampling module, configured to generate a first level signal when the voltage signal is greater than a first preset threshold, or generate a second level signal when the voltage signal is less than the first preset threshold;
[0007] a fault latch module, connected to the determination module, configured to continuously output a fault latch signal after receiving the first level signal, or output the second level signal in the case of receiving the second level signal and receiving a reset signal; and
[0008] an output module, connected to the fault latch module, configured to output a lock signal for locking a driving signal according to the fault latch signal, or output an unlock signal for unlocking the driving signal according to the second level signal, the driving signal being used for driving the switching device to work.
[0009] In some embodiments, the fault latch module comprises:
[0010] a first resistor, one end of which is connected to a power supply end, and the other end of which is connected to the determination module;
[0011] a second resistor, one end of which is connected to the other end of the first resistor and the determination module;
[0012] a third resistor, one end of which is connected to a ground end, and the other end of which is connected to the other end of the second resistor and an input end of the output module.
[0013] a first diode, a positive electrode of the first diode being connected to the other end of the third resistor;
[0014] a fourth resistor, one end of the fourth resistor being connected to a negative electrode of the first diode, and the other end of the fourth resistor being connected to an output end of the output module.
[0015] In some embodiments, the determination module comprises:
[0016] a first comparator, a first input end of the first comparator being connected to the sampling module, a second input end of the first comparator being connected to a first reference voltage end, and an output end of the first comparator being connected to the fault latch module;
[0017] the first comparator is configured to generate the first level signal in a case where the voltage signal is greater than a first reference voltage of the first reference voltage end, or generate a second level signal in a case where the voltage signal is greater than the first preset threshold value, the first reference voltage being equal to the first preset threshold value.
[0018] In some embodiments, the output module comprises:
[0019] a second comparator, a first input end of the second comparator being connected to the fault latch module, and a second input end of the second comparator being connected to a second reference voltage end;
[0020] a fifth resistor, one end of the fifth resistor being connected to a power supply end, and the other end of the fifth resistor being connected to an output end of the second comparator;
[0021] the second comparator is configured to output the lockout signal in a case where a signal output by the fault latch module is less than a second reference voltage of the second reference voltage end, or generate the unlock signal in a case where the signal output by the fault latch module is greater than the second reference voltage of the second reference voltage end, the second level signal being greater than the second reference voltage, and the fault latch signal being less than the second reference voltage.
[0022] In some embodiments, the latch protection circuit further comprises:
[0023] a controller, the controller being connected to the fault latch module, and the controller being configured to provide the reset signal to the fault latch module.
[0024] In some embodiments, the fault latch module further comprises a second diode, a positive electrode of the second diode being connected to the controller, and a negative electrode of the second diode being connected to an input end of the output module.
[0025] In some embodiments, the latch protection circuit further comprises:
[0026] The driver is connected with the controller and the output module, and is used for outputting a driving signal according to the unlocking signal and the reset signal, or stopping outputting the driving signal according to the blocking signal.
[0027] In some embodiments, the signal to be detected is one of a current signal or a voltage signal.
[0028] In some embodiments, the sampling module comprises a Hall sensor.
[0029] The switch protection system of the embodiments of the present application comprises a switch device and the latch protection circuit of any of the above embodiments.
[0030] In the latch protection circuit and the switch protection system of the embodiments of the present application, the signal to be detected is collected by the sampling module and is generated into a voltage signal, so that the determination module can compare the voltage signal with a first preset threshold to determine whether the signal to be detected is abnormal, and can generate a first level signal when the voltage signal is greater than the first preset threshold (i.e. when it is confirmed that the signal to be detected is abnormal), so that the fault latch module continuously outputs a fault latch signal after receiving the first level signal, so that the output module can continuously output a blocking signal to block the driving signal according to the fault latch signal. In this way, even if the signal to be detected returns to normal, the driving signal is still in a blocked state, and the switch device stops working, thereby realizing fault latching of the switch device and protecting the safety of the switch device. Until the fault latch module receives a reset signal and receives a second level signal representing that the signal to be detected returns to normal, the switch device can work according to the driving signal.
[0031] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS
[0032] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings.
[0033] Figure 1 is a module schematic diagram of the fault latch circuit of the embodiments of the present application.
[0034] Figure 2 is a circuit schematic diagram of the fault latch circuit of the embodiments of the present application.
[0035] Explanation of main element symbols:
[0036] 10 - latch protection circuit, Vcc - power terminal, Vref1 - first reference voltage terminal, Vref2 - second reference voltage terminal, GND - ground terminal, 11 - sampling module, 12 - determination module, U1 - first comparator, 13 - fault latch module, R1 - first resistor, R2 - second resistor, R3 - third resistor, R4 - fourth resistor, R5 - fifth resistor, D1 - first diode, D2 - second diode, 14 - output module, U2 - second comparator, R5 - fifth resistor, 15 - controller, 16 - driver. DETAILED DESCRIPTION
[0037] Embodiments of the present application are described below in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.
[0038] Referring to Figure 1 The embodiment of the present application provides a latch protection circuit 10 for protecting a switching device, the latch protection circuit 10 comprising a sampling module 11, a determination module 12, a fault latch module 13 and an output module 14, wherein the sampling module 11 is configured to collect a to-be-tested signal output by the switching device and generate a voltage signal according to the to-be-tested signal; the determination module 12 is connected to the sampling module 11 and configured to generate a first level signal when the voltage signal is greater than a first preset threshold, or generate a second level signal when the voltage signal is less than the first preset threshold; the fault latch module 13 is connected to the determination module 12 and configured to continuously output a fault latch signal after receiving the first level signal, or output the second level signal when receiving the second level signal and receiving a reset signal; and the output module 14 is connected to the fault latch module 13 and configured to output a lock signal for locking a driving signal according to the fault latch signal, or output an unlock signal for unlocking the driving signal according to the second level signal, the driving signal being used to drive the switching device to work.
[0039] In the latch protection circuit 10 of the embodiment, the sampling module 11 collects the to-be-tested signal of the switching device and generates a voltage signal from the to-be-tested signal, so that the determination module 12 can compare the voltage signal with a first preset threshold value, determine whether the to-be-tested signal is abnormal, and generate a first level signal when the voltage signal is greater than the first preset threshold value (i.e., when it is confirmed that the to-be-tested signal is abnormal), so that the fault latch module 13 continuously outputs a fault latch signal after receiving the first level signal, so that the output module 14 can continuously output a blocking signal to block the driving signal according to the fault latch signal, control the switching device to stop working, and thus even if the to-be-tested signal returns to normal, the switching device can also be prevented from working, the fault latch of the switching device is realized, and the safety of the switching device is protected. Until the fault latch module 13 receives a reset signal and receives a second level signal representing that the to-be-tested signal returns to normal, the fault latch is released, and the switching device normally works under the driving of the driving signal.
[0040] The switching device can be a semiconductor power device. In the embodiment, the switching device can be taken as an example of an insulated gate bipolar transistor (IGBT), that is, the latch protection circuit 10 of the application is used to protect the IGBT. It can be understood that when overcurrent or overvoltage occurs in the circuit of the IGBT, the IGBT is easily damaged, and therefore, the IGBT needs to be controlled to stop working, thereby protecting the IGBT from damage.
[0041] The driving signal is a signal for driving the switching device to work, and the driving signal can be a pulse width adjustment signal. After the driving signal is blocked, the switching device can stop working. The to-be-tested signal can be an analog signal such as a voltage or current signal. For example, in the embodiment, the to-be-tested signal can be taken as an example of a current, that is, the latch protection circuit 10 can collect the current signal output by the switching device and determine whether the switching device needs to be protected according to the current signal output by the switching device.
[0042] The sampling module 11 can be connected to the switching device. For example, when the switching device is an IGBT, the sampling module 11 can be connected to the emitter of the IGBT, used to collect the to-be-tested signal output by the switching device, and convert the to-be-tested signal into a voltage signal.
[0043] The first preset threshold is used to determine whether the to-be-tested signal is abnormal. When the voltage signal is greater than the first preset threshold, it indicates that the to-be-tested signal is abnormal, which is easy to cause damage to the switch device. When the voltage signal is less than the first preset threshold, it indicates that the to-be-tested signal is normal. The first preset threshold can be pre-stored in the determination module 12, or the determination module 12 can obtain it from other modules or circuits when receiving the voltage signal. Understandably, the size of the first preset threshold can be set as needed, and the specific value is not limited. In this way, the determination module 12 can compare the voltage signal with the first preset threshold. Thus, it is determined whether the to-be-tested signal is abnormal. That is, the determination module 12 outputs a first level signal when the voltage signal is greater than the first preset threshold, and outputs a second level signal when it is less than the first preset threshold.
[0044] The first level signal can be a low level signal, and the second level signal is a high level signal. That is, the determination module 12 outputs a high level signal when the to-be-tested signal is normal, and outputs a low level signal when the to-be-tested signal is abnormal.
[0045] It should be noted that the blocking drive signal means that the drive signal is blocked and cannot reach the switch device. The unlocking drive signal means that the drive signal can reach the switch device and drive the switch device to work.
[0046] The fault latching module 13 continuously outputs the fault latching signal after receiving the first level signal, so that the output module 14 can continuously output the blocking signal of the blocking drive signal according to the fault latching signal, so that the switch device stops working without the drive signal. Because the fault latching module 13 only outputs the second level signal to control the output module 14 to output the unlocking signal when it receives the reset signal and the second level signal, so that the switch device can receive the drive signal and work normally. Therefore, even when the to-be-tested signal returns to normal, that is, when the determination module 12 outputs the second level signal, the switch device can still stop working. In this way, the latch protection circuit 10 provides a reliable and continuous protection signal, which improves the reliability of the switch device.
[0047] Further, the latch protection circuit 10 further includes a controller 15 and a driver 16. The controller 15 can be connected to the fault latching module 13, the output module 14 and the driver 16. The controller 15 can output a reset signal to the driver 16 and output a reset signal to the fault latching module 13, so that the fault latching module 13 realizes the unlocking of the fault state. The reset signal can be generated by the controller 15 after receiving the blocking signal and completing the fault disposal, or according to user input. The controller 15 can also receive the blocking signal and the unlocking signal output by the output module 14. In this way, the controller 15 can know whether the switch device has an abnormal condition.
[0048] The driver 16 is connected to the controller 15, the output module 14 and the switching device, and is configured to output a driving signal according to the unlocking signal and the reset signal, so as to control the switching device to work, and the driver 16 is further configured to stop outputting the driving signal according to the blocking signal, so as to control the switching device to stop working, that is, the blocking signal is used to block the driver 16 from outputting the driving signal.
[0049] Referring to Figure 2 In some embodiments, the determination module 12 comprises a first comparator U1, a first input end of the first comparator U1 is connected to the sampling module 11, a second input end of the first comparator U1 is connected to a first reference voltage end Vref1, and an output end of the first comparator U1 is connected to the fault latching module 13. The first comparator U1 is configured to generate a first level signal in a case that the voltage signal is greater than a first reference voltage of the first reference voltage end Vref1, or generate a second level signal in a case that the voltage signal is less than a first preset threshold value, and the first reference voltage is equal to the first preset threshold value.
[0050] The first comparator U1 can be an open-drain comparator. The first input end can be a positive input end of the open-drain comparator, and the second input end can be a negative input end of the open-drain comparator. It can be understood that the open-drain comparator is an electronic circuit for comparing the sizes of two voltage signals and outputting a corresponding logic level, and the output end has an open-drain characteristic, that is, the output end is an open circuit (high impedance state) or a ground state (low impedance state). That is, when the first comparator U1 outputs the first level signal, the output end of the first comparator U1 is in the ground state, and when the first comparator U1 outputs the second level signal, the output end of the first comparator U1 is in the high impedance state.
[0051] In this way, the determination module 12 can accurately output a level signal representing whether the switching device is abnormal according to the voltage signal generated by the sampling module 11 through the setting of the first comparator U1, and the structure is simple and reliable compared with logic gates, transistors and other components.
[0052] Further referring to Figure 2 In some embodiments, the fault latching module 13 comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first diode D1. One end of the first resistor R1 is connected to a power supply end Vcc, and the other end of the first resistor R1 is connected to the determination module 12. One end of the second resistor R2 is connected to the other end of the first resistor R1 and the determination module 12; one end of the third resistor R3 is connected to a ground end GND, and the other end of the third resistor R3 is connected to the other end of the second resistor R2 and an input end of the output module 14; a positive electrode of the first diode D1 is connected to the other end of the third resistor R3; one end of the fourth resistor R4 is connected to a negative electrode of the first diode D1, and the other end of the fourth resistor R4 is connected to an output end of the output module 14.
[0053] In this embodiment, the first level signal, the fault latching signal and the blocking signal are low level signals, and the second level signal, the reset signal and the unblocking signal are high level signals.
[0054] Specifically, one end of the first resistor R1 is connected to the power supply end Vcc, the other end of the first resistor R1 is connected to the output end of the first comparator U1, and one end of the second resistor R2 is connected to the other end of the first resistor R1 and the output end of the first comparator U1. After the first level signal is output at the output end of the first comparator U1, that is, when the output end of the first comparator U1 is in a low resistance state, a loop is formed by the first resistor R1, the second resistor R2 and the third resistor R3, at this time, a voltage is formed on the third resistor R3 by the power supply end Vcc passing through the first resistor R1, the second resistor R2 and the third resistor R3 to the ground end GND. Since the output end of the first comparator U1 outputs a low resistance state, the voltage at the connection between the third resistor R3 and the output module 14 is a low level signal, that is, the fault latching signal is output to the input end of the output module 14, so that the output module 14 can output the blocking signal according to the fault latching signal, that is, output a low level signal, thereby controlling the switch device to stop working. After the second level signal is output at the output end of the first comparator U1, that is, when the output end of the first comparator U1 is in a high resistance state, since the output module 14 outputs the blocking signal (low level signal), at this time, the third resistor R3 is actually connected in parallel with the first capacitor and the fourth resistor R4, and the voltage of the third resistor R3 is low (the fault latching signal), so that the output module 14 can continue to output the blocking signal according to the fault latching signal, thereby controlling the switch device to stop working.
[0055] Further, the other end of the third resistor R3 can also be connected to the controller 15, when the fault needs to be recovered, the controller 15 can output the reset signal to the other end of the third resistor R3. When the reset signal is received at the other end of the third resistor R3, since the other end of the third resistor R3 is connected to the input end of the output module 14, the input end of the output module 14 inputs a high level signal, and the output end of the output module 14 outputs the unblocking signal (high level signal), at this time, the fault latching module 13 is reset.
[0056] In some embodiments, the output module 14 includes a second comparator U2 and a fifth resistor R5, wherein the first input end of the second comparator U2 is connected to the fault latching module 13, the second input end of the second comparator U2 is connected to the first reference voltage end Vref2, one end of the fifth resistor R5 is connected to the power supply end Vcc, and the other end of the fifth resistor R5 is connected to the output end of the second comparator U2.
[0057] The second comparator U2 is configured to output a blocking signal when the signal output by the fault latching module 13 is less than the second reference voltage of the second reference voltage terminal Vref2, or generate an unblocking signal when the signal output by the fault latching module 13 is greater than the second reference voltage of the second reference voltage terminal Vref2, the second level signal being greater than the second reference voltage, and the fault latching signal being less than the second reference voltage.
[0058] In this way, the output module 14 can accurately output the level signal representing whether the switching device is abnormal according to the voltage signal generated by the sampling module 11 through the second comparator U2 and the fifth resistor R5, and the structure is simple and reliable compared with components such as logic gates and transistors.
[0059] As shown in FIG. 1, in some embodiments, the fault latching module 13 further comprises a second diode D2, the positive electrode of the second diode D2 being connected to the controller 15, and the negative electrode of the second diode D2 being connected to the input terminal of the output module 14. Figure 2
[0060] In this way, the second diode D2 can prevent the voltage of the input terminal of the output module 14 from flowing back to the controller 15, thereby ensuring the safety of the controller 15.
[0061] In some embodiments, the sampling module 11 comprises a Hall sensor. As can be understood by those skilled in the art, the Hall sensor is a sensor based on the Hall effect, which detects the presence or strength of a magnetic field by using the potential difference generated by the movement of charged particles in a magnetic field, and the Hall sensor can convert the current in the circuit into a voltage signal.
[0062] In this way, the sampling module 11 can detect the current output by the switching device and generate a voltage signal, thereby ensuring that the latching protection circuit 10 provides a protection signal to protect the switching device when the switching device has an overcurrent or short circuit phenomenon.
[0063] The switching protection system of the embodiments of the present application comprises a switching device and the latching protection circuit 10 of any of the above embodiments.
[0064] In the switch protection system of the embodiment of the present application, the sampling module 11 collects the to-be-tested signal and generates a voltage signal from the to-be-tested signal, so that the determination module 12 can compare the voltage signal with the first preset threshold, determine whether the to-be-tested signal is abnormal, and generate a first level signal when the voltage signal is greater than the first preset threshold (i.e., when it is confirmed that the to-be-tested signal is abnormal), so that the fault latching module 13 continuously outputs the fault latching signal after receiving the first level signal, so that the output module 14 can continuously output the blocking signal to block the driving signal according to the fault latching signal. In this way, even when the to-be-tested signal returns to normal, the driving signal is still in a blocked state, and the switch device stops working, thereby realizing fault latching of the switch device and protecting the safety of the switch device. Until the fault latching module 13 receives the reset signal and receives a second level signal representing that the to-be-tested signal returns to normal, the switch device can work according to the driving signal.
[0065] In the description of the present specification, the description of the terms "one embodiment", "certain embodiments", "exemplary embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0066] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.
Claims
1. A latch protection circuit for protecting a switching device, characterized by The latch protection circuit comprises: a sampling module, configured to collect a to-be-tested signal output by the switching device and generate a voltage signal according to the to-be-tested signal; a determination module connected to the sampling module, configured to generate a first level signal if the voltage signal is greater than a first preset threshold, or generate a second level signal if the voltage signal is less than the first preset threshold; a fault latch module connected to the determination module, configured to continuously output a fault latch signal after receiving the first level signal, or output the second level signal if the second level signal is received and a reset signal is received; and an output module connected to the fault latch module, configured to output a lock signal for locking a driving signal according to the fault latch signal, or output an unlock signal for unlocking the driving signal according to the second level signal, the driving signal being used for driving the switching device to work.
2. The latch protection circuit of claim 1, wherein, The determination module comprises: a first comparator, a first input end of the first comparator being connected to the sampling module, a second input end of the first comparator being connected to a first reference voltage end, and an output end of the first comparator being connected to the fault latch module; the first comparator being configured to generate the first level signal if the voltage signal is greater than a first reference voltage of the first reference voltage end, or generate the second level signal if the voltage signal is less than the first preset threshold, the first reference voltage being equal to the first preset threshold.
3. The latch protection circuit according to claim 1 or 2, characterized in that, The fault latch module comprises: a first resistor, one end of the first resistor being connected to a power supply end, and the other end of the first resistor being connected to the determination module; a second resistor, one end of the second resistor being connected to the other end of the first resistor and the determination module; a third resistor, one end of the third resistor being connected to a ground end, and the other end of the third resistor being connected to the other end of the second resistor and an input end of the output module; a first diode, a positive electrode of the first diode being connected to the other end of the third resistor; a fourth resistor, one end of the fourth resistor being connected to a negative electrode of the first diode, and the other end of the fourth resistor being connected to an output end of the output module.
4. The latch-up protection circuit of claim 2, wherein, The output module comprises: a second comparator, a first input end of the second comparator being connected to the fault latch module, and a second input end of the second comparator being connected to a second reference voltage end; a fifth resistor, one end of the fifth resistor being connected to a power supply end, and the other end of the fifth resistor being connected to an output end of the second comparator; the second comparator being configured to output the lock signal if a signal output by the fault latch module is less than a second reference voltage of the second reference voltage end, or generate the unlock signal if the signal output by the fault latch module is greater than the second reference voltage of the second reference voltage end, the second level signal being greater than the second reference voltage, and the fault latch signal being less than the second reference voltage.
5. The latch-up protection circuit of claim 1, wherein, The latch protection circuit further comprises: a controller connected to the fault latch module, the controller being configured to provide the reset signal to the fault latch module.
6. The latch protection circuit of claim 5, wherein, The fault latch module further comprises a second diode, a positive electrode of the second diode being connected to the controller, and a negative electrode of the second diode being connected to an input end of the output module.
7. The latch-up protection circuit of claim 5, wherein, The latch protection circuit further comprises: A driver is connected between the controller and the output module, for outputting a driving signal according to the unlocking signal and the reset signal, or stopping outputting the driving signal according to the blocking signal.
8. The latch-up protection circuit of claim 1, wherein, The signal to be measured is one of a current signal or a voltage signal.
9. The latch-up protection circuit of claim 1, wherein, The sampling module comprises a Hall sensor.
10. A switch protection system characterized by, The switch protection system comprises a switch device and the latch protection circuit according to any one of claims 1-9.