CN210468823U - Reverse voltage prevention circuit - Google Patents
Reverse voltage prevention circuit Download PDFInfo
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- CN210468823U CN210468823U CN201921014760.2U CN201921014760U CN210468823U CN 210468823 U CN210468823 U CN 210468823U CN 201921014760 U CN201921014760 U CN 201921014760U CN 210468823 U CN210468823 U CN 210468823U
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Abstract
The utility model discloses a prevent reverse voltage's circuit. The circuit includes: the drain electrode of the first MOSFET is connected with the cathode of the battery pack, the grid electrode of the first MOSFET is connected with the drain electrode of the second MOSFET and one end of the first current limiting module, and the source electrode of the first MOSFET is connected with a load; the grid electrode of the second MOSFET is connected with one end of the second current limiting module, and the source electrode of the second MOSFET is connected with the anode of the battery pack; the other end of the first current limiting module is connected with the anode and the load of the battery pack; the other end of the second current limiting module is connected with the negative electrode of the battery pack; the first MOSFET is an N-channel MOSFET, and the second MOSFET is an N-channel MOSFET. According to the utility model provides an embodiment, can prevent the inside reverse voltage that or group battery place return circuit produced of group battery fast.
Description
Technical Field
The utility model relates to a new forms of energy field especially relates to a prevent reverse voltage's circuit.
Background
Electric vehicles have become a trend in the automotive industry to replace fuel-powered vehicles. The endurance mileage, the service life and the use safety of the battery pack are particularly important for the use of the electric automobile. A common power supply scheme for an electric vehicle is to use two batteries, one battery is a high-voltage battery pack used for supplying power to high-power devices such as a motor, and the other battery is a low-voltage battery pack used for supplying power to a controller, such as a vehicle control unit and a battery management system. In practical use, it is necessary to prevent the load from being damaged by a reverse voltage generated inside the battery pack or in a circuit in which the battery pack is placed.
As shown in fig. 1, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is connected in series with the negative output terminal of the battery pack to prevent the load from being damaged by the reverse voltage generated inside the battery pack or in a circuit where the battery pack is located. Wherein, the current limiting module connected with the MOSFET in series plays a role of current limiting. However, due to the parasitic capacitance parameter inside the MOSFET, the reverse voltage suddenly applied to the battery pack or the circuit in which the battery pack is located cannot be quickly prevented.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a prevent reverse voltage's circuit can stop the reverse voltage that the inside or group battery place return circuit of group battery produced fast.
According to an aspect of the present invention, there is provided a reverse voltage prevention circuit, the circuit including:
the drain electrode of the first MOSFET is connected with the cathode of the battery pack, the grid electrode of the first MOSFET is connected with the drain electrode of the second MOSFET and one end of the first current limiting module, and the source electrode of the first MOSFET is connected with a load;
the grid electrode of the second MOSFET is connected with one end of the second current limiting module, and the source electrode of the second MOSFET is connected with the anode of the battery pack;
the other end of the first current limiting module is connected with the anode and the load of the battery pack;
the other end of the second current limiting module is connected with the negative electrode of the battery pack;
the first MOSFET is an N-channel MOSFET, and the second MOSFET is an N-channel MOSFET.
In one embodiment, the first current limiting module includes a first resistor network having one end connected to the gate of the first MOSFET and the other end connected to the positive terminal of the battery pack and the load.
In one embodiment, the second current limiting module includes a second resistor network disposed between the gate of the second MOSFET and the cathode of the battery pack.
In one embodiment, the circuit for preventing reverse voltage further comprises:
the first overvoltage protection module is arranged between the grid electrode of the first MOSFET and the source electrode of the first MOSFET and used for providing overvoltage protection for the first MOSFET.
In one embodiment, the first overvoltage protection module includes:
and the anode of the first diode is connected with the source electrode of the first MOSFET, and the cathode of the first diode is connected with the grid electrode of the first MOSFET.
In one embodiment, the circuit for preventing reverse voltage further comprises:
and the second overvoltage protection module is arranged between the source electrode of the second MOSFET and the grid electrode of the second MOSFET.
In one embodiment, the second overvoltage protection module includes:
and the bidirectional clamping diode is arranged between the source electrode of the second MOSFET and the gate electrode of the second MOSFET.
In one embodiment, the circuit for preventing reverse voltage further comprises:
the first high-voltage filtering module is arranged between the anode of the battery pack and the cathode of the battery pack and used for filtering transient high voltage to protect the first MOSFET and the second MOSFET;
and/or the presence of a gas in the gas,
and the second high-voltage filtering module is arranged between the source electrode of the first MOSFET and the anode of the battery pack and used for filtering transient high voltage to protect the first MOSFET and the second MOSFET.
In one embodiment, the first high voltage filter module comprises a first capacitor disposed between the positive pole of the battery pack and the negative pole of the battery pack.
In one embodiment, the second high voltage filter module includes a second capacitor disposed between the source of the first MOSFET and the anode of the battery pack.
According to the embodiment of the utility model provides a prevent reverse voltage's circuit, if the inside reverse voltage that produces of group battery, because second MOSFET's grid voltage is greater than second MOSFET's source voltage, so second MOSFET switches on, and the parasitic capacitance of first MOSFET discharges with higher speed that switches on of second MOSFET to shorten first MOSFET's off-time, thereby realize stopping the reverse voltage that the inside or group battery place return circuit of group battery produced fast, in order to prevent the damage of reverse voltage to the load.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a reverse voltage prevention circuit;
fig. 2 is a schematic structural diagram of a reverse voltage prevention circuit according to a first embodiment of the present invention;
FIG. 3 is an equivalent circuit diagram of the reverse voltage prevention circuit of FIG. 2;
fig. 4 is a schematic structural diagram of a reverse voltage prevention circuit according to a second embodiment of the present invention;
fig. 5 is a schematic structural diagram of a reverse voltage prevention circuit according to a third embodiment of the present invention;
fig. 6 is a schematic structural diagram of a reverse voltage prevention circuit according to a fourth embodiment of the present invention;
fig. 7 is a schematic structural diagram of a reverse voltage prevention circuit according to a fifth embodiment of the present invention;
fig. 8 is a schematic structural diagram of a reverse voltage prevention circuit according to a sixth embodiment of the present invention.
Detailed Description
The features and exemplary embodiments of various aspects of the present invention will be described in detail below, and in order to make the objects, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Fig. 2 is a schematic structural diagram of a reverse voltage prevention circuit according to a first embodiment of the present invention. As shown in fig. 2, the circuit for preventing directional voltage provided by the embodiment of the present invention includes:
the drain of the first MOSFET Q1, the drain of the first MOSFET Q1 are connected with the cathode of the battery pack P1, the gate of the first MOSFET Q1 is connected with the drain of the second MOSFET Q2 and one end of the first current limiting module L1, and the source of the first MOSFET Q1 is connected with the load.
And a second MOSFET Q2, wherein the gate of the second MOSFET Q2 is connected with one end of the second current limiting module L2, and the source of the second MOSFET Q2 is connected with the anode of the battery pack P1.
And the other end of the first current limiting module L1, L1, is connected with the anode of the battery pack P1 and the load.
And the other end of the second current limiting module L2, L2, is connected with the negative pole of the battery pack P1.
The first MOSFET is an N-channel MOSFET, and the second MOSFET is also an N-channel MOSFET.
Fig. 3 shows an equivalent schematic diagram of the reverse voltage prevention circuit in fig. 2. The principle that the reverse voltage preventing circuit provided by the present invention can rapidly block the reverse voltage generated inside the battery pack P1 or the circuit in which the battery pack P1 is located is explained in detail with reference to fig. 3.
As shown in fig. 3, the first MOSFET Q1 may be equivalent to the on-resistance RDS and the parasitic capacitance C1 in fig. 3.
With continued reference to fig. 3, the second MOSFET Q2 may be equivalent to the switch K1 and the parasitic diode D1 of the second MOSFET Q2 in parallel with the switch K1.
As shown in fig. 3, one end of the resistor RDS is connected to the negative electrode of the battery pack P1 and one end of the second current limiting module L2, and the other end of the resistor RDS is connected to one end of the capacitor C1 and the load.
The other end of the parasitic capacitor C1 is connected to one end of the switch K1, the cathode of the diode D1, the other end of the second current limiting module L2, and one end of the first current limiting module L1, respectively. The other end of the switch K1 is connected to the positive electrode of the battery pack P1. The anode of the diode D1 is connected to the anode of the battery P1. The other end of the first current limiting module L1 is connected to the positive electrode of the battery pack P1 and the load.
In an embodiment of the present invention, when the voltage of the battery pack P1 is applied to the first MOSFET Q1, the first battery pack P1 starts charging the parasitic capacitance C1. The parasitic capacitor C1 needs to reach a certain charge before the first MOSFET Q1 will turn on. Similarly, when a reverse voltage is generated in the battery P1 or in the circuit of the battery P1, the parasitic capacitor C1 is required to discharge all the charges, and the first MOSFET Q1 is turned off.
Since the first MOSFET Q1 is damaged by a large charging current of the parasitic capacitor C1, the first current limiting module L1 is provided. However, if a reverse voltage is generated in the battery pack P1 or the circuit in which the battery pack P1 is located, the first current limiting module L1 limits the turn-off speed of the first MOSFET Q1.
If the second MOSFET Q2 is not included in fig. 3, when a reverse voltage is generated inside the battery pack P1 or in a loop where the battery pack P1 is located, the battery pack P1, the on-resistance RDS, the parasitic capacitor C1 and the first current limiting module L1 form a discharging loop of the parasitic capacitor C1, and the off-time t of the first MOSFET Q1 can be determined by the following expression:
t＝C1(RDS+R0) (1)
wherein C1 is the capacitance of the parasitic capacitance of the first MOSFET Q1, R0Is the resistance value of the first current limiting module L1. Therefore, the resistance of the first current limiting module L1 limits the turn-off speed of the first MOSFET Q1.
Referring to fig. 3, due to the presence of the second MOSFET Q2, when a reverse voltage is generated inside the battery pack P1 or in a loop where the battery pack P1 is located, the second MOSFET Q2 is turned on, i.e., the switch K1 is in a closed state, because the gate voltage of the second MOSFET Q2 is greater than the voltage at the source of the second MOSFET Q2. The battery pack P1, the on-resistance RDS, the parasitic capacitor C1 and the closed switch K1 form a discharge loop of the parasitic capacitor C1, and the off-time t of the first MOSFET Q1 can be determined by the following expression:
t＝C1×RDS (2)
when a reverse voltage is generated inside the battery pack P1 or in a loop where the battery pack P1 is located, due to the conduction of the second MOSFET Q2, the reverse voltage generated inside the battery pack P1 will form a back voltage across the parasitic capacitor C1 through the conducting second MOSFET Q2, thereby avoiding the influence of the first current limiting module L1 on the turn-off time of the first MOSFET Q1, and accelerating the discharge of the parasitic capacitor C1.
Generally, the resistance of the first current limiting module L1 is much larger than the resistance of the on-resistance RDS of the first MOSFET Q1. As can be seen from the expressions (1) and (2), due to the conduction of the N-channel MOSFET Q2, the off time of the first MOSFET Q1 is greatly reduced, so that the off speed of the first MOSFET Q1 is increased, the reverse voltage generated inside the battery pack P1 or in a loop where the battery pack P1 is located is quickly prevented, and the load is effectively protected from the reverse voltage.
Fig. 4 is a schematic structural diagram of a reverse voltage prevention circuit according to a second embodiment of the present invention. Fig. 4 shows a specific structure of the first current limiting module L1.
As shown in fig. 4, the first current limiting module L1 includes a resistor network N1. One end of the resistor network N1 is connected to the gate of the first mosfet q1, and the other end of the resistor network N1 is connected to the positive terminal of the battery P1 and the load.
Continuing to refer to fig. 4, as a specific example, the resistor network N1 includes a resistor R1, one end of the resistor R1 is connected to the gate of the first MOSFET Q1, and the other end of the resistor R1 is connected to the positive terminal of the battery P1 and the load.
The embodiment of the present invention is not particularly limited to the structure of the resistor network N1.
Fig. 5 is a schematic structural diagram of a reverse voltage prevention circuit according to a third embodiment of the present invention. The reverse voltage prevention circuit of fig. 5 is different from the reverse voltage prevention circuit of fig. 4 in that fig. 5 illustrates a specific structure of the second current limiting module L2.
In some embodiments, the second current limiting module L2 includes a resistor network N2, one end of the resistor network N2 is connected to the gate of the second MOSFET Q2, and the other end of the resistor network N2 is connected to the cathode of the battery P1.
In the embodiment of the present invention, by providing the second current limiting module L2, the second MOSFET Q2 can be prevented from being destroyed by too large current, so as to limit the current.
Continuing to refer to fig. 5, as a specific example, the resistor network N2 includes a resistor R2, one end of the resistor R2 is connected to the gate of the second MOSFET Q2, and the other end of the resistor R2 is connected to the cathode of the battery P1.
The embodiment of the present invention is not particularly limited to the structure of the resistor network N2.
Fig. 6 is a schematic structural diagram of a reverse voltage prevention circuit according to a fourth embodiment of the present invention. The reverse voltage prevention circuit of fig. 6 is different from the reverse voltage prevention circuit of fig. 5 in that the reverse voltage prevention circuit of fig. 6 includes a first overvoltage protection module E1 disposed between the source of the first MOSFET Q1 and the gate of the first MOSFET Q1.
The first overvoltage protection module E1 is used to provide overvoltage protection for the first MOSFET Q1, and prevent the first MOSFET Q1 from being damaged due to an excessively high voltage between the gate of the first MOSFET Q1 and the source of the first MOSFET Q1.
As an example, with continued reference to fig. 6, the first overvoltage protection module E1 includes a diode D2, an anode of the diode D2 connected to the source of the first MOSFET Q1, and a cathode of the diode D2 connected to the gate of the first MOSFET Q1. The diode D2 may be a clamping diode.
As for the structure of the first overvoltage protection module E1, the embodiment of the invention is not particularly limited as long as the first MOSFET Q1 can be prevented from being damaged by an excessively high voltage between the gate of the first MOSFET Q1 and the source of the first MOSFET Q1.
Fig. 7 shows a reverse voltage prevention circuit according to a fifth embodiment of the present invention. The reverse voltage prevention circuit of fig. 7 is different from the reverse voltage prevention circuit of fig. 6 in that the reverse voltage prevention circuit of fig. 6 further includes a second overvoltage protection module E2 disposed between the gate of the second MOSFET Q2 and the source of the second MOSFET Q2.
The second overvoltage protection module E2 is used to provide overvoltage protection for the second MOSFET Q2, and prevent the second MOSFET Q2 from being damaged due to the excessive voltage between the gate of the second MOSFET Q2 and the source of the second MOSFET Q2.
With continued reference to fig. 7, the second overvoltage protection module E2 includes a bidirectional clamping diode D3. A bidirectional clamp diode D3 is disposed between the source of the second MOSFET Q2 and the gate of the second MOSFET Q2.
As for the structure of the second overvoltage protection module E2, the embodiment of the invention is not particularly limited as long as the second MOSFET Q2 can be prevented from being damaged by an excessively high voltage between the gate of the second MOSFET Q2 and the source of the second MOSFET Q2.
Fig. 8 shows a reverse voltage prevention circuit according to a sixth embodiment of the present invention. The reverse voltage preventing circuit of fig. 8 is different from the reverse voltage preventing circuit of fig. 7 in that the reverse voltage preventing circuit of fig. 8 further includes a first high voltage filtering module F1 and a first high voltage filtering module F2.
The first high-voltage filtering module F1 is disposed between the positive electrode of the battery P1 and the negative electrode of the battery P1, and is configured to filter a transient high voltage to protect the first MOSFET Q1 and the second MOSFET Q2.
The second high-voltage filtering module F2 is disposed between the source of the first MOSFET Q1 and the positive electrode of the battery P1, and is used for filtering a transient high voltage to protect the first MOSFET Q1 and the second MOSFET Q2.
In some embodiments, the reverse voltage protection circuit may include only one of the first high voltage filtering module F1 and the first high voltage filtering module F2, and may also filter transient excessive voltages to protect the first MOSFET Q1 and the second MOSFET Q2 from high voltage.
In one example, the first high pressure filtration module F1 includes a capacitance C2 disposed between the positive pole of the battery pack P1 and the negative pole of the battery pack P1.
In one example, the second high pressure filtration module F2 includes a capacitor C3 disposed between the source of the first mosfet q1 and the positive terminal of the battery P1.
In the embodiment of the present invention, the transient over-voltage can be filtered by providing the capacitor C2 and the capacitor C3, so as to further protect the first MOSFET Q1 and the second MOSFET Q2 better.
It will be appreciated by persons skilled in the art that the above embodiments are illustrative and not restrictive. Different features which are present in different embodiments may be combined to advantage. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art upon studying the drawings, the specification, and the claims. Any reference signs in the claims shall not be construed as limiting the scope. The functions of the various parts appearing in the claims may be implemented by a single hardware or software module. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope of the present invention, and these modifications or replacements should be covered within the protection scope of the present invention.
Claims (10)
1. A circuit for preventing reverse voltage, the circuit comprising:
the drain electrode of the first MOSFET is connected with the negative electrode of the battery pack, the grid electrode of the first MOSFET is respectively connected with the drain electrode of the second MOSFET and one end of the first current limiting module, and the source electrode of the first MOSFET is connected with a load;
the grid electrode of the second MOSFET is connected with one end of a second current limiting module, and the source electrode of the second MOSFET is connected with the anode of the battery pack;
the other end of the first current limiting module is connected with the anode of the battery pack and the load respectively;
the other end of the second current limiting module is connected with the negative electrode of the battery pack;
the first MOSFET is an N-channel MOSFET, and the second MOSFET is an N-channel MOSFET.
2. The circuit of claim 1, wherein the first current limiting module comprises a first resistor network having one end connected to the gate of the first MOSFET and another end connected to the positive electrode of the battery pack and the load.
3. The circuit of claim 1, wherein the second current limiting module comprises a second resistor network disposed between the gate of the second MOSFET and the cathode of the battery pack.
4. The circuit of claim 1, further comprising:
the first overvoltage protection module is arranged between the grid electrode of the first MOSFET and the source electrode of the first MOSFET and used for providing overvoltage protection for the first MOSFET.
5. The circuit of claim 4, wherein the first overvoltage protection module comprises:
a first diode, an anode of the first diode being connected to a source of the first MOSFET, and a cathode of the first diode being connected to a gate of the first MOSFET.
6. The circuit of claim 1, further comprising:
and the second overvoltage protection module is arranged between the source electrode of the second MOSFET and the grid electrode of the second MOSFET.
7. The circuit of claim 6, wherein the second overvoltage protection module comprises:
a bidirectional clamping diode disposed between the source of the second MOSFET and the gate of the second MOSFET.
8. The circuit of claim 1, further comprising:
the first high-voltage filtering module is arranged between the anode of the battery pack and the cathode of the battery pack and used for filtering transient high voltage to protect the first MOSFET and the second MOSFET;
and/or the presence of a gas in the gas,
and the second high-voltage filtering module is arranged between the source electrode of the first MOSFET and the anode of the battery pack and used for filtering transient high voltage to protect the first MOSFET and the second MOSFET.
9. The circuit of claim 8, wherein the first high voltage filtering module comprises a first capacitor disposed between a positive pole of the battery and a negative pole of the battery.
10. The circuit of claim 8, wherein the second high voltage filter module comprises a second capacitor disposed between the source of the first MOSFET and the positive terminal of the battery pack.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921014760.2U CN210468823U (en) | 2019-07-02 | 2019-07-02 | Reverse voltage prevention circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921014760.2U CN210468823U (en) | 2019-07-02 | 2019-07-02 | Reverse voltage prevention circuit |
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| Publication Number | Publication Date |
|---|---|
| CN210468823U true CN210468823U (en) | 2020-05-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921014760.2U Active CN210468823U (en) | 2019-07-02 | 2019-07-02 | Reverse voltage prevention circuit |
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| CN (1) | CN210468823U (en) |
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- 2019-07-02 CN CN201921014760.2U patent/CN210468823U/en active Active
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Effective date of registration: 20220118 Address after: 352100 science and technology building, No. 2, Xingang Road, Zhangwan Town, Jiaocheng District, Ningde City, Fujian Province Patentee after: Ningde Shidai Runzhi Software Technology Co.,Ltd. Address before: 352100 Xingang Road, Zhangwan Town, Jiaocheng District, Ningde, Fujian 2 Patentee before: Contemporary Amperex Technology Co.,Ltd. |