CN210468777U - Reverse voltage prevention circuit - Google Patents

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 the driving power supply, and the source electrode of the second MOSFET is connected with the anode of the battery pack; the driving power supply is used for providing a driving voltage for the second MOSFET so as to drive the second MOSFET to be conducted; the other end of the first current limiting module is connected with the anode and the load of the battery pack; the first MOSFET is an N-channel MOSFET, and the second MOSFET is a P-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

Reverse voltage prevention circuit

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 existing inside the MOSFET, the reverse voltage suddenly applied by the battery pack 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 the driving power supply, and the source electrode of the second MOSFET is connected with the anode of the battery pack;

the driving power supply is used for providing a driving voltage for the second MOSFET so as to drive the second MOSFET to be conducted;

the other end of the first current limiting module is connected with the anode and the load of the battery pack;

the first MOSFET is an N-channel MOSFET, and the second MOSFET is a P-channel MOSFET.

In one embodiment, the circuit for preventing reverse voltage further comprises:

and the second current limiting module is arranged between the driving power supply and the grid electrode of the second MOSFET.

In one embodiment, the second current limiting module includes a first resistor network, one end of the first resistor network is connected to the driving power supply, and the other end of the first resistor network is connected to the gate of the second MOSFET.

In one embodiment, the circuit for preventing reverse voltage further comprises:

and the voltage division module is arranged between the grid electrode of the second MOSFET and the cathode of the battery pack.

In one embodiment, the voltage dividing module comprises a second resistor network, one end of the second resistor network is connected with the grid electrode of the second MOSFET, and the other end of the second resistor network is connected with the negative electrode of the battery pack.

In one embodiment, the circuit for preventing reverse voltage further comprises a voltage dividing module disposed between the gate of the second MOSFET and the cathode of the battery pack, the driving power source is the battery pack, and the gate of the second MOSFET is connected to the anode of the battery pack.

In one embodiment, the driving power source is a power chip supplied with power by a battery pack, one end of the power chip is connected with the anode of the battery pack, and the other end of the power chip is connected with the grid electrode of the second MOSFET.

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 capacitor is arranged between the anode of the battery pack and the cathode of the battery pack;

and/or the presence of a gas in the gas,

and the second capacitor is arranged between the source electrode 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 inside or the group battery place return circuit of group battery produces reverse voltage, parasitic diode through utilizing the second MOSFET forms the back pressure at first MOSFET's parasitic capacitance both ends, can discharge with higher speed first MOSFET's parasitic capacitance to the off-time that has shortened first MOSFET, thereby realize stopping the reverse voltage that the inside or the 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;

fig. 9 is a schematic structural diagram of a reverse voltage prevention circuit according to a seventh embodiment of the present invention;

fig. 10 is a schematic structural diagram of a reverse voltage prevention circuit according to an eighth embodiment of the present invention;

fig. 11 is a schematic structural diagram of a reverse voltage prevention circuit according to a ninth embodiment of the present invention;

fig. 12 is a schematic structural diagram of a reverse voltage prevention circuit according to a tenth 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 P2, 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 the driving power supply P1, and the source of the second MOSFET Q2 is connected with the anode of the battery pack P2.

And the driving power supply P1 is used for providing a driving voltage to the second MOSFET Q2 so as to drive the second MOSFET Q2 to be conducted.

And the other end of the first current limiting module L1, L1, is connected with the anode of the battery pack P2 and the load.

The first MOSFET is an N-channel MOSFET, and the second MOSFET is a P-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 is explained in detail with reference to fig. 3.

As shown in fig. 3, the first MOSFET Q1 can 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. Wherein the driving power supply P1 is used to drive the switch K1 to close.

As shown in fig. 3, one end of the resistor RDS is connected to the negative electrode of the battery P2, 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 anode of the diode D1, 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 P2. The cathode of the diode D1 is connected to the anode of the battery P2. The other end of the first current limiting module L1 is connected to the positive electrode of the battery pack P2 and the load.

In an embodiment of the present invention, when the voltage of the battery P2 is applied to the first MOSFET Q1, the battery P2 starts charging the parasitic capacitor 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 P2 or in the circuit of the battery P2, 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 P2 or the circuit in which the battery pack P2 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 P2 or in a loop where the battery pack P2 is located, the battery pack P2, 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 P2 or in a loop where the battery pack P2 is located, the battery pack P2, the on-resistance RDS, the parasitic capacitance C1 and the parasitic diode D1 form a discharge loop of the parasitic capacitance C1, and the off-time t of the first MOSFET Q1 may be determined by the following expression:

t＝C1×RDS(2)

due to the existence of the second MOSFET Q2, a reverse voltage generated inside the battery pack P2 or in a loop where the battery pack P2 is located will form a back voltage across the parasitic capacitor C1 through the parasitic diode D1 of the 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 RDS of the on-resistance of the first MOSFET Q1. As can be seen from the expressions (1) and (2), due to the P-channel MOSFET Q2, the turn-off time of the first MOSFET Q1 is greatly reduced, so that the turn-off speed of the first MOSFET Q1 is increased, and the reverse voltage generated inside the battery pack P2 or in a loop where the battery pack P2 is located is quickly prevented, thereby effectively protecting the load from the reverse voltage.

In the embodiment of the present invention, the second MOSFET Q2 can not only increase the turn-off speed of the first MOSFET Q1, but also increase the turn-on speed of the first MOSFET Q1. After the battery pack P2 powers the first MOSFET Q1, the battery pack P2 charges the parasitic capacitance C1 of the first MOSFET Q1. When the parasitic capacitor C1 starts to charge, the driving power source P1 drives the second MOSFET Q2 to turn on. Due to the conduction of the second MOSFET Q2, the charging current of the parasitic capacitor C1 is increased, so that the charging speed of the parasitic capacitor C1 is increased, and the conduction time of the first MOSFET Q1 is reduced. That is, the turn-on of the second MOSFET Q2 may increase the turn-on speed of the first MOSFET Q1.

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 anode of the battery P2 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 P2 and the load.

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 preventing circuit of fig. 5 is different from the reverse voltage preventing circuit of fig. 4 in that the reverse voltage preventing circuit of fig. 5 further includes a second current limiting module L2 disposed between the driving power source P1 and the gate of the second MOSFET Q2.

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.

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 preventing circuit of fig. 6 is different from the reverse voltage preventing circuit of fig. 5 in that fig. 6 illustrates a specific structure of the second current limiting module L2.

With continued reference to fig. 6, the second current limiting module L2 includes a resistor network N2, one end of the resistor network N2 is connected to the driving power source P1, and the other end of the resistor network N2 is connected to the gate of the second MOSFET Q2. As a specific example, the resistor network N2 includes a resistor R2, one end of the resistor R2 is connected to the driving power source P1, and the other end of the resistor R2 is connected to the gate of the second MOSFET Q2.

Fig. 7 is a schematic structural diagram of a reverse voltage prevention circuit according to a fifth embodiment of the present invention. The reverse voltage preventing circuit of fig. 7 is different from the reverse voltage preventing circuit of fig. 6 in that the reverse voltage preventing circuit of fig. 7 further includes a voltage dividing block disposed between the gate of the second MOSFET Q2 and the cathode of the battery pack P2.

With continued reference to fig. 7, the voltage divider module includes a resistor network N3, one end of the resistor network N3 is connected to the gate of the second MOSFET Q2, and the other end of the resistor network N3 is connected to the cathode of the battery P2. As a specific example, the resistor network N3 includes a resistor R3, one end of the resistor R3 is connected to the gate of the second MOSFET Q2, and the other end of the resistor R3 is connected to the cathode of the battery P2.

The utility model discloses an in some embodiments, through setting up the partial pressure module, can set up the driving voltage that drive second MOSFET Q2 switched on in a flexible way, the suitability scope is wider, and the flexibility is higher.

Fig. 8 is a schematic structural diagram of a reverse voltage prevention circuit according to a sixth embodiment of the present invention. The reverse voltage prevention circuit in fig. 8 is different from the reverse voltage prevention circuit in fig. 7 in that fig. 8 shows an exemplary structure of the driving power source P1.

Referring to fig. 8, the driving power source P1 is a battery pack P2. Wherein, the gate of the second MOSFET Q2 is connected with the anode of the battery P2.

By using the battery pack P2 as a driving power supply of the second MOSFET Q2, the structure of the circuit is simplified and the cost is reduced.

Fig. 9 is a schematic diagram illustrating a reverse voltage prevention circuit according to a seventh embodiment of the present invention. The reverse voltage prevention circuit in fig. 9 is different from the reverse voltage prevention circuit in fig. 4 in that fig. 9 shows another exemplary structure of the driving power source P1.

Referring to fig. 9, the driving power supply P1 is a power chip supplied with power from the battery pack P2. One end of the power chip is connected with the positive electrode of the battery pack P2, and the other end of the power chip is connected with the grid electrode of the second MOSFET Q2.

By using the power chip supplied with power from the battery pack as the driving power source of the second MOSFET Q2, the driving voltage of the second MOSFET Q2 can be flexibly set, and the application range is wider.

In some embodiments of the present invention, the power chip in fig. 9 may not be powered by the battery pack P2, and may have an independent power supply.

Fig. 10 shows a reverse voltage prevention circuit according to an eighth embodiment of the present invention. The reverse voltage prevention circuit of fig. 10 is different from the reverse voltage prevention circuit of fig. 8 in that the reverse voltage prevention circuit of fig. 10 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, preventing the first MOSFET Q1 from being damaged by excessive 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. 10, 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.

Fig. 11 shows a reverse voltage prevention circuit according to a ninth embodiment of the present invention. The reverse voltage prevention circuit of fig. 11 is different from the reverse voltage prevention circuit of fig. 10 in that the reverse voltage prevention circuit of fig. 11 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, preventing the second MOSFET Q2 from being damaged by excessive voltage between the gate of the second MOSFET Q2 and the source of the second MOSFET Q2.

With continued reference to fig. 11, 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.

Fig. 12 shows a reverse voltage prevention circuit according to a tenth embodiment of the present invention. The reverse voltage prevention circuit of fig. 12 is different from the reverse voltage prevention circuit of fig. 11 in that the reverse voltage prevention circuit of fig. 12 further includes a capacitor C2 disposed between the anode of the battery pack P2 and the cathode of the battery pack P2, and a capacitor C3 disposed between the source of the first mosfet q1 and the anode of the battery pack P2.

In some examples, the reverse voltage prevention circuit may include only one of the capacitor C2 or the capacitor C3, thereby filtering out transient over-voltages to protect the first MOSFET Q1 and the second MOSFET Q2.

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 (12)

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 a driving power supply, and the source electrode of the second MOSFET is connected with the anode of the battery pack;

the driving power supply is used for providing a driving voltage for the second MOSFET so as to drive the second MOSFET to be conducted;

the other end of the first current limiting module is connected with the anode of the battery pack and the load respectively;

the first MOSFET is an N-channel MOSFET, and the second MOSFET is a P-channel MOSFET.

2. The circuit of claim 1, further comprising:

and the second current limiting module is arranged between the driving power supply and the grid electrode of the second MOSFET.

3. The circuit of claim 2, wherein the second current limiting module comprises a first resistor network, one end of the first resistor network being connected to the driving power supply, the other end of the first resistor network being connected to the gate of the second MOSFET.

4. The circuit of claim 1, further comprising:

and the voltage division module is arranged between the grid electrode of the second MOSFET and the negative electrode of the battery pack.

5. The circuit of claim 4, wherein the voltage divider module comprises a second resistor network, one end of the second resistor network is connected to the gate of the second MOSFET, and the other end of the second resistor network is connected to the negative terminal of the battery pack.

6. The circuit of claim 2, further comprising a voltage divider module disposed between a gate of the second MOSFET and a cathode of the battery pack, wherein the driving power source is the battery pack, and the gate of the second MOSFET is connected to the anode of the battery pack.

7. The circuit of claim 1, wherein the driving power source is a power chip supplied with power from the battery pack, one end of the power chip is connected to the positive electrode of the battery pack, and the other end of the power chip is connected to the gate of the second MOSFET.

8. 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.

9. The circuit of claim 8, 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.

10. 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.

11. The circuit of claim 10, 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.

12. The circuit of claim 1, further comprising:

the first capacitor is arranged between the positive electrode of the battery pack and the negative electrode of the battery pack;

and/or the presence of a gas in the gas,

and the second capacitor is arranged between the source electrode of the first MOSFET and the anode of the battery pack.

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