Protection circuit and vehicle
By designing the discharge unit and the driving unit in the protection circuit, the charge stored in the parasitic capacitance of the P-type MOS tube is quickly released, which solves the problem of the MOS tube remaining on when the reverse connection or negative surge voltage, resulting in equipment damage, and achieves rapid shutdown protection in the event of abnormal situations.
Patent Information
- Application Number
- CN202311506758.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-13
- Publication Date
- 2025-05-13
AI Technical Summary
In application scenarios where MOS tubes are used to prevent reverse connection, the MOS tube may remain on because the charge stored in the parasitic capacitor is not released, causing the equipment to be powered to be damaged when the power supply unit is reversed or negative surge voltage.
A protection circuit is designed, including a P-type MOS tube, a discharge unit and a drive unit. By quickly releasing the charge between the gate and source of the P-type MOS tube by the discharge current of the discharge unit, the MOS tube is quickly turned off.
When the power supply unit is reversed or negative surge voltage, the protection circuit can quickly turn off the P-type MOS tube to prevent damage to the equipment to be powered.
Smart Images
Figure CN119994827A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of vehicle technology, and in particular to a protection circuit and a vehicle. Background Art
[0002] Protection circuits are generally used to prevent the power supply unit from being reversely connected to the device to be powered, preventing the device to be powered from being damaged. Protection circuits are widely used in automotive electronic systems. In related solutions, for some application scenarios with low power supply current, diodes can be directly used to prevent reverse connection. For some application scenarios with low power supply current, diodes are generally no longer applicable, so MOS tubes are used to prevent reverse connection.
[0003] However, in the application scenario where MOS tubes are used to prevent reverse connection, there will be certain problems. Specifically, since there is a certain parasitic capacitance between the gate and source of the MOS tube, and the charge stored in the parasitic capacitance is not released, the MOS tube will still remain in the on state until the charge stored in the parasitic capacitance is released. Therefore, if the power supply unit is suddenly reversed, or a negative surge voltage occurs due to some unexpected factors, since the MOS tube will remain on for a period of time, it is still possible to damage the device to be powered. Summary of the invention
[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a protection circuit and a vehicle.
[0005] In a first aspect, the present disclosure provides a protection circuit, comprising:
[0006] P-type MOS tube, discharge unit and drive unit;
[0007] The source of the P-type MOS tube is used to electrically connect to a power supply unit, and the drain of the P-type MOS tube is used to electrically connect to a device to be powered; the discharge unit and the drive unit are connected in parallel, and are both electrically connected between the gate of the P-type MOS tube and a control terminal of a protection circuit;
[0008] The source potential of the P-type MOS tube is greater than the drain potential of the P-type MOS tube, the path where the driving unit is located is turned on, and the path where the discharge unit is located is turned off; the source potential of the P-type MOS tube is less than or equal to the drain potential of the P-type MOS tube, the path where the driving unit is located and the path where the discharge unit is located are both turned on, and the discharge current of the path where the discharge unit is located is greater than the discharge current of the path where the driving unit is located.
[0009] Optionally, the discharge unit includes a first resistor and a first diode;
[0010] The first end of the first resistor is electrically connected to the gate of the P-type MOS tube, the second end of the first resistor is electrically connected to the cathode of the first diode, and the anode of the first diode is electrically connected to the control end of the protection circuit.
[0011] Optionally, the driving unit includes a second resistor, a first end of the second resistor is electrically connected to the gate of the P-type MOS tube, and a second end of the second resistor is electrically connected to the control end of the protection circuit.
[0012] Optionally, a resistance value of the first resistor is smaller than a resistance value of the second resistor.
[0013] Optionally, further comprising a second diode;
[0014] An anode of the second diode is electrically connected to a first end of the second resistor, and a cathode of the second diode is electrically connected to a source of the P-type MOS tube.
[0015] Optionally, a reverse breakdown voltage of the second diode is less than or equal to a maximum withstand voltage between the gate and the source of the P-type MOS tube.
[0016] Optionally, the first resistor is an adjustable resistor.
[0017] Optionally, a third diode is further included;
[0018] The cathode of the third diode is electrically connected to the source of the P-type MOS tube, and the anode of the third diode is electrically connected to the control end of the protection circuit.
[0019] Optionally, it also includes a first capacitor and / or a second capacitor, the first capacitor is electrically connected between the drain of the P-type MOS tube and the control end of the protection circuit; the second capacitor is electrically connected between the source of the P-type MOS tube and the control end of the protection circuit.
[0020] In a second aspect, the present disclosure further provides a vehicle, comprising a protection circuit as described in any one of the first aspects.
[0021] The present disclosure provides a protection circuit and a vehicle. In the protection circuit, when the source potential of the P-type MOS tube is greater than the drain potential of the P-type MOS tube, the power supply unit normally supplies power to the device to be powered in a positive connection manner, and the path where the drive unit is located is turned on, that is, the P-type MOS tube can be controlled to be turned on normally. When the drain potential of the P-type MOS tube is greater than the source potential of the P-type MOS tube, it means that the power supply unit is reversely connected or a negative surge voltage occurs, the paths where the discharge units are located are all turned on, and the discharge current of the path where the discharge units are located is greater than the discharge current of the path where the drive unit is located, so the charge between the gate and the source of the P-type MOS tube can be released in a faster manner, that is, the charge stored in the parasitic capacitance between the gate and the source of the P-type MOS tube. After the charge stored in the parasitic capacitance is released, the P-type MOS tube can be quickly turned off to prevent the device to be powered from being damaged due to the reverse connection of the power supply unit or the occurrence of a negative surge voltage. In summary, the protection circuit provided by the present disclosure can quickly turn off the P-type MOS tube in the event of a reverse connection of the power supply unit or a negative surge voltage, thereby preventing damage to the device to be powered. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A schematic diagram of a protection circuit structure provided by an embodiment of the present disclosure;
[0023] Figure 2 A schematic diagram of another protection circuit structure provided in an embodiment of the present disclosure;
[0024] Figure 3 A schematic diagram of another protection circuit structure provided in an embodiment of the present disclosure;
[0025] Figure 4 A schematic diagram of another protection circuit structure provided in an embodiment of the present disclosure;
[0026] Figure 5 A schematic diagram of another protection circuit structure provided in an embodiment of the present disclosure. DETAILED DESCRIPTION
[0027] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.
[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.
[0029] The protection circuit and the vehicle provided in the embodiments of the present disclosure are exemplarily described below with reference to the accompanying drawings.
[0030] Figure 1 A schematic diagram of a protection circuit structure provided in an embodiment of the present disclosure, the protection circuit includes:
[0031] P-type MOS tube 101 , discharge unit 102 and drive unit 103 .
[0032] The source of the P-type MOS tube 101 is used to electrically connect to the power supply unit 104, and the drain of the P-type MOS tube 101 is used to electrically connect to the device to be powered 105. The discharge unit 102 and the drive unit 103 are connected in parallel and are both electrically connected between the gate of the P-type MOS tube 101 and the control terminal 106 of the protection circuit.
[0033] The source potential of the P-type MOS tube 101 is greater than the drain potential of the P-type MOS tube 101, the path where the driving unit 103 is located is turned on, and the path where the discharge unit 102 is located is turned off. The source potential of the P-type MOS tube 101 is less than or equal to the drain potential of the P-type MOS tube 101, the path where the driving unit 103 is located and the path where the discharge unit 102 is located are both turned on, and the discharge current of the path where the discharge unit 102 is located is greater than the discharge current of the path where the driving unit 103 is located.
[0034] Exemplarily, the power supply unit 104 represents a functional unit or device that can provide electric energy to the device to be powered 105, for example, it can be a battery, etc. In the embodiment of the present disclosure, the power supply unit 104 can provide direct current to the device to be powered 105. The device to be powered 105 represents a functional unit that needs to receive electric energy, such as a motor, a controller, etc. The discharge unit 102 represents a functional unit that can provide charge to the gate of the P-type MOS tube 101 to eliminate the parasitic capacitance of the gate of the P-type MOS tube 101. The driving unit 103 represents a functional unit that can make the source and drain of the P-type MOS tube 101 conductive. The control terminal 106 of the protection circuit represents an end that can control the P-type MOS tube 101 to be turned on or off. In the embodiment of the present disclosure, the P-type MOS tube 101 is a low-level conductive device, so the control terminal 106 can be a fixed low-level terminal, such as a ground terminal.
[0035] When the P-type MOS tube 101 needs to be turned on, that is, the power supply unit 104 needs to supply power to the device to be powered 105, the power supply unit 104 provides a high level. At this time, the source potential of the P-type MOS tube 101 is greater than the drain potential of the P-type MOS tube 101, and is also greater than the gate potential of the P-type MOS tube 101. There is a voltage difference between the source and the gate of the P-type MOS tube 101, which charges the parasitic capacitance between the gate and the source of the P-type MOS tube 101. When the parasitic capacitance is stably full, the potential of the source is equal to the potential output by the power supply unit 104. , for example, it can be VBAT. Since the driving unit 103 is turned on, the gate potential of the P-type MOS tube 101 can be pulled to the potential of the control end 106. Since it is a P-type MOS tube 101, the gate potential of the P-type MOS tube 101 can be 0 at this time. Since the gate potential of the P-type MOS tube 101 is lower than the source potential of the P-type MOS tube 101 (the potential difference between the gate potential and the source potential needs to reach a certain difference), the P-type MOS tube 101 is turned on, and the power supply unit 104 can normally supply power to the device to be powered 105.
[0036] If the source potential of the P-type MOS tube 101 is less than or equal to the drain potential of the P-type MOS tube 101, it indicates that an abnormality occurs in the power supply unit 104, for example, the power supply unit 104 is reversely connected or a negative surge voltage occurs. The essence of the power supply unit 104 being reversely connected or the negative surge voltage occurring is similar, and both can be simply considered that the power supply unit 104 suddenly changes from providing a high level to the source of the P-type MOS tube 101 to providing a low level. Due to the existence of parasitic capacitance between the source and the gate of the P-type MOS tube 101, and because the charge stored in the parasitic capacitance has not been fully released, the P-type MOS tube 101 will remain turned on at this time, and the device to be powered 105 may be damaged at this time.
[0037] In this regard, the discharge unit 102 in the embodiment of the present disclosure can remain turned on when the source potential of the P-type MOS tube 101 is less than or equal to the drain potential of the P-type MOS tube 101, and the discharge current of the path where the discharge unit 102 is located is greater than the discharge current of the path where the driving unit 103 is located. Since the discharge current is larger, the charge stored in the parasitic capacitance between the gate and the source of the P-type MOS tube 101 can be released at a faster rate, thereby enabling the P-type MOS tube 101 to be turned off at a faster rate, thereby protecting the device 105 to be powered.
[0038] In summary, the protection circuit provided in the embodiment of the present disclosure can quickly shut down the P-type MOS tube 101 when the power supply unit 104 is reversely connected or a negative surge voltage occurs, thereby preventing damage to the device to be powered 105.
[0039] Figure 2A schematic diagram of another protection circuit structure provided by an embodiment of the present disclosure is shown in FIG. 1 . In some embodiments, the discharge unit 102 includes a first resistor 201 and a first diode 202 .
[0040] A first end of the first resistor 201 is electrically connected to the gate of the P-type MOS transistor 101 , a second end of the first resistor 201 is electrically connected to the cathode of the first diode 202 , and an anode of the first diode 202 is electrically connected to the control terminal 106 of the protection circuit.
[0041] Exemplarily, due to the presence of the first diode 202, when the source potential of the P-type MOS tube 101 is greater than the drain potential of the P-type MOS tube 101, the path where the discharge unit 102 is located is cut off, and when the source potential of the P-type MOS tube 101 is less than or equal to the drain potential of the P-type MOS tube 101, the path where the discharge unit 102 is located is turned on. Specifically, the function of the first resistor 201 is to limit the current of the path where it is located to prevent excessive current, but in order to achieve rapid discharge and make the P-type MOS tube 101 turn off quickly, the resistance of the first resistor 201 cannot be too large. The resistance of the first resistor 201 can be set between tens and hundreds of ohms, for example, it can be between 50 ohms and 500 ohms. The forward conduction of the first diode 202 should be as small as possible, for example, it can be 0.2V, or even less than 0.2V.
[0042] Based on the above solution, the P-type MOS tube 101 can be quickly turned off.
[0043] In some embodiments, the driving unit 103 includes a second resistor, a first end of the second resistor is electrically connected to the gate of the P-type MOS transistor 101 , and a second end of the second resistor is electrically connected to the control end 106 of the protection circuit.
[0044] Exemplarily, the second resistor can be set at more than 1000 ohms. In some embodiments, in order to enable the path where the first resistor 201 is located to turn off the P-type MOS tube 101 at a faster rate, the resistance of the first resistor 201 is smaller than the resistance of the second resistor. Since the resistance of the first resistor 201 is smaller than the resistance of the second resistor, the discharge current is larger, and the charge stored in the parasitic capacitor between the gate and the source of the P-type MOS tube 101 can be released at a faster rate, that is, the P-type MOS tube 101 can be turned off at a faster rate.
[0045] Figure 3 A schematic diagram of another protection circuit structure provided by an embodiment of the present disclosure. In some embodiments, a second diode 301 is further included.
[0046] An anode of the second diode 301 is electrically connected to the first end of the second resistor, and a cathode of the second diode 301 is electrically connected to the source of the P-type MOS transistor 101 .
[0047] For example, when the P-type MOS tube 101 works normally, that is, the power supply unit 104 can provide a high level to the device to be powered 105 and the P-type MOS tube 101 is turned on, the voltage output by the power supply unit 104 may be too high, which may also cause damage to the P-type MOS tube 101.
[0048] To this end, the second diode 301 can be used to prevent the voltage output by the power supply unit 104 from being too high. Specifically, the second diode 301 can be reversely broken down when the output voltage of the power supply unit 104 is too high, thereby protecting the P-type MOS tube 101 from being damaged.
[0049] In some embodiments, the reverse breakdown voltage of the second diode 301 is less than or equal to the maximum withstand voltage between the gate and the source of the P-type MOS transistor 101 .
[0050] Specifically, if the reverse breakdown voltage of the second diode 301 is less than or equal to the maximum withstand voltage between the gate and the source of the P-type MOS tube 101, then when the output voltage of the power supply unit 104 reaches the reverse breakdown voltage, the second diode 301 will reversely break down, and the current will be limited by the second resistor to keep the voltage between the gate and the source of the P-type MOS tube 101 near the reverse breakdown voltage of the second diode 301 and will not exceed the maximum withstand voltage between the gate and the source of the P-type MOS tube 101. The second resistor can also be set to a kilo-ohm resistor to prevent the power consumption of the second diode 301 from being too high.
[0051] Through the above solution, it is possible to prevent the P-type MOS tube 101 from being damaged due to the overly high output voltage of the power supply unit 104 .
[0052] In some embodiments, the first resistor 201 is an adjustable resistor.
[0053] For example, the higher the resistance of the first resistor 201, the smaller the discharge current and the lower the discharge rate, and the lower the resistance of the first resistor 201, the larger the discharge current and the higher the discharge rate. Therefore, based on the above scheme, the turn-off time of the P-type MOS tube 101 can be adjusted by the adjustable first resistor 201, which can not only achieve the effect of timely turning off the MOS tube 101, but also perform current limiting.
[0054] Figure 4 A schematic diagram of another protection circuit structure provided by an embodiment of the present disclosure. In some embodiments, a third diode 401 is further included.
[0055] The cathode of the third diode 401 is electrically connected to the source of the P-type MOS transistor 101 , and the anode of the third diode 401 is electrically connected to the control terminal 106 of the protection circuit.
[0056] Exemplarily, the third diode 401 may be a clamping diode for clamping. Specifically, the protection circuit may not be able to completely prevent the negative surge voltage from damaging the device to be powered 105, for example, the P-type MOS tube 101 is not turned off in time, etc. To this end, the negative surge voltage of the power supply unit 104 can be clamped at a lower negative voltage by the third diode 401 to prevent the negative voltage from being too high and damaging the device to be powered 105.
[0057] Figure 5 A schematic diagram of another protection circuit structure provided by an embodiment of the present disclosure. In some embodiments, a first capacitor 501 and / or a second capacitor 502 are further included, wherein the first capacitor 501 is electrically connected between the drain of the P-type MOS tube 101 and the control terminal 106 of the protection circuit. The second capacitor 502 is electrically connected between the source of the P-type MOS tube 101 and the control terminal 106 of the protection circuit.
[0058] Exemplarily, the first capacitor 501 and the second capacitor 502 can play a filtering role, filtering out stray AC signals with too high frequency that may be output by the power supply unit 104, and filtering out stray AC signals with too high frequency that may be received by the device to be powered 105, to prevent damage to the device to be powered 105.
[0059] An embodiment of the present disclosure further provides a vehicle, the vehicle comprising a protection circuit as described in any one of the above protection circuit embodiments.
[0060] Specifically, since the vehicle includes the above-mentioned protection circuit, it can also achieve the same or at least similar technical effects as the above-mentioned protection circuit, which will not be repeated here.
[0061] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
[0062] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.
Claims
1. A protection circuit, characterized in that: include: P-type MOS tube, discharge unit and drive unit; The source of the P-type MOS tube is used to electrically connect to a power supply unit, and the drain of the P-type MOS tube is used to electrically connect to a device to be powered; the discharge unit and the drive unit are connected in parallel, and are both electrically connected between the gate of the P-type MOS tube and the control end of the protection circuit; The source potential of the P-type MOS tube is greater than the drain potential of the P-type MOS tube, the path where the driving unit is located is turned on, and the path where the discharge unit is located is turned off; the source potential of the P-type MOS tube is less than or equal to the drain potential of the P-type MOS tube, the path where the driving unit is located and the path where the discharge unit is located are both turned on, and the discharge current of the path where the discharge unit is located is greater than the discharge current of the path where the driving unit is located.
2. The protection circuit according to claim 1, characterized in that: The discharge unit includes a first resistor and a first diode; The first end of the first resistor is electrically connected to the gate of the P-type MOS tube, the second end of the first resistor is electrically connected to the cathode of the first diode, and the anode of the first diode is electrically connected to the control end of the protection circuit.
3. The protection circuit according to claim 2, characterized in that: The driving unit includes a second resistor, a first end of the second resistor is electrically connected to the gate of the P-type MOS tube, and a second end of the second resistor is electrically connected to the control end of the protection circuit.
4. The protection circuit according to claim 3, characterized in that: The resistance value of the first resistor is smaller than the resistance value of the second resistor.
5. The protection circuit according to claim 3, characterized in that: Also including a second diode; An anode of the second diode is electrically connected to a first end of the second resistor, and a cathode of the second diode is electrically connected to a source of the P-type MOS tube.
6. The protection circuit according to claim 5, characterized in that: The reverse breakdown voltage of the second diode is less than or equal to the maximum withstand voltage between the gate and the source of the P-type MOS tube.
7. The protection circuit according to claim 2, characterized in that: The first resistor is an adjustable resistor.
8. The protection circuit according to claim 1, characterized in that: Also including a third diode; The cathode of the third diode is electrically connected to the source of the P-type MOS tube, and the anode of the third diode is electrically connected to the control end of the protection circuit.
9. The protection circuit according to claim 1, characterized in that: It also includes a first capacitor and / or a second capacitor, wherein the first capacitor is electrically connected between the drain of the P-type MOS tube and the control end of the protection circuit; and the second capacitor is electrically connected between the source of the P-type MOS tube and the control end of the protection circuit.
10. A vehicle, characterized in that: The vehicle comprises a protection circuit as claimed in any one of claims 1 to 9.