CN210007435U

CN210007435U - Reverse voltage prevention circuit

Info

Publication number: CN210007435U
Application number: CN201920976644.2U
Authority: CN
Inventors: 傅焱辉; 楚乐
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Ningde Shidai Runzhi Software Technology Co ltd
Priority date: 2019-06-26
Filing date: 2019-06-26
Publication date: 2020-01-31
Anticipated expiration: 2029-06-26

Abstract

The utility model discloses an prevent reverse voltage's circuit, this circuit includes metal oxide semiconductor field effect transistor MOSFET, MOSFET's drain electrode is connected with the positive pole of group battery, MOSFET's grid and the end of the one-way module of conducting and the end of current-limiting module are connected, MOSFET's source electrode and load are connected, the one-way module of conducting, the other end of the one-way module of conducting is connected with the negative pole of group battery, the current direction of the one-way module of conducting is the other end of the one-way module of conducting and flows to the end of the one-way module of conducting, current-limiting module, the other end of current-limiting module is connected with the negative pole and the load of group battery.

Description

Reverse voltage prevention circuit

Technical Field

The utility model relates to a new forms of energy field especially relates to prevent reverse voltage's circuit.

Background

The driving range, service life and use safety of the battery pack are particularly important for the use of the electric automobile, the common scheme of power supply of the electric automobile is that two batteries are used for supplying power, batteries are high-voltage battery packs which are used for supplying power to high-power equipment such as a motor, and batteries are low-voltage battery packs which are used for supplying power to a controller such as a whole vehicle controller and a battery management system.

As shown in fig. 1, it is now possible to prevent the load from being damaged by the reverse voltage generated inside the battery pack or in a circuit in which the battery pack is located by connecting Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs) in series at the positive output terminal of the battery pack.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides an kinds of reverse voltage's circuit prevents, 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 at , there are provided kinds of reverse voltage prevention circuits, including:

the drain electrode of the MOSFET is connected with the anode of the battery pack, the grid electrode of the MOSFET is connected with the end of the unidirectional conduction module and the end of the current-limiting module, and the source electrode of the MOSFET is connected with a load;

the other end of the unidirectional conduction module is connected with the negative electrode of the battery pack, and the current direction of the unidirectional conduction module is that the other end of the unidirectional conduction module flows to the end of the unidirectional conduction module;

the other terminals of the th and th current limiting modules are connected to the negative pole and load of the battery pack.

In embodiments, the unidirectional turn-on module includes a th diode, an anode of the th diode is connected to a cathode of the battery pack, and a cathode of the th diode is connected to a gate of the MOSFET.

In embodiments, the circuitry for preventing reverse voltage further comprises:

the th end of the switch module is connected with the driving power supply, the second end of the switch module is connected with the grid electrode of the MOSFET, and the third end of the switch module is connected with the negative electrode of the battery pack;

the driving power supply is used for providing driving voltage for the switch module so as to drive the switch module to be in a closed state;

and the pull-down module is arranged between the th end of the switch module and the negative electrode of the battery pack.

In embodiments, the switch module comprises a transistor, wherein the terminal of the switch module is a base of the transistor, the second terminal of the switch module is a collector of the transistor, and the third terminal of the switch module is an emitter of the transistor.

In embodiments, the circuitry for preventing reverse voltage further comprises:

and the second current limiting module is arranged between the driving power supply and the th end of the switch module.

In embodiments, the second current limiting module includes a resistor network, a terminal of the resistor network is connected to the driving power source, and another terminal of the resistor network is connected to a terminal of the switch module.

In embodiments, the pull-down module includes a second resistor network, wherein a terminal of the second resistor network is connected to a terminal of the switch module, and another terminal of the second resistor network is connected to the negative terminal of the battery pack.

In embodiments, the driving power source is a battery pack, and the terminal of the switch module is connected to the positive terminal of the battery pack.

In embodiments, the driving power source is a power chip powered by the battery pack, a terminal of the power chip is connected to the positive electrode of the battery pack, and another terminal of the power chip is connected to the terminal of the switch module.

In embodiments, the circuitry for preventing reverse voltage further comprises:

and the overvoltage protection module is arranged between the source electrode of the MOSFET and the end of the current limiting module and is used for providing overvoltage protection for the MOSFET.

In embodiments, the overvoltage protection module includes:

and the anode of the second diode is connected with the end of the current-limiting module, and the cathode of the second diode is connected with the source of the MOSFET.

In embodiments, the circuitry for preventing reverse voltage further comprises:

an th capacitor disposed 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 MOSFET and the cathode 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, form the back pressure at MOSFET's parasitic capacitance both ends through the one-way module that switches on to MOSFET's parasitic capacitance discharges with higher speed, has shortened MOSFET's off-time, thereby realizes 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 protection circuit according to an 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.

Detailed Description

The features and exemplary embodiments of various aspects of the present invention will be described in detail below to make the objects, aspects, and advantages of the present invention more apparent, and the present invention will be described in step detail below with reference to the accompanying drawings and embodiments.

It should be noted that, in this document, relational terms such as , second and the like are only used to distinguish entities or operations from another entities or operations, but not necessarily requires or implies any such actual relationship or order between these entities or operations, furthermore, 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 family of elements does not include only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 2 shows a schematic structural diagram of a reverse voltage preventing circuit according to an embodiment of the present invention , as shown in fig. 2, the reverse voltage preventing circuit according to an embodiment of the present invention includes:

the drain electrode of the MOSFET Q1, the drain electrode of the MOSFET Q1 and the anode of the battery pack P2 are connected, the gate electrode of the MOSFET Q1 is connected with the end of the unidirectional turn-on module G and the end of the current-limiting module L1, and the source electrode of the MOSFET Q1 is connected with a load.

And the other end of the unidirectional conduction module G is connected with the negative electrode of the battery pack P2, and the current direction of the unidirectional conduction module G is that the other end of the unidirectional conduction module G flows to the end of the unidirectional conduction module G.

The other ends of the th current limiting module L1 and the th current limiting module L1 are connected with the negative pole and the load of the battery pack P2.

The MOSFET Q1 is a P-channel MOSFET.

Fig. 3 shows an equivalent circuit 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 P2 or the circuit in which the battery pack P2 is located is explained in detail with reference to fig. 3.

As shown in fig. 3, the MOSFET Q1 may be equivalent to the on-resistance RDS and the parasitic capacitance C1 in fig. 3.

As shown in fig. 3, an terminal of the resistor RDS is connected to the positive electrode of the battery P2, another terminal of the resistor RDS is connected to the load, a terminal of the parasitic capacitor C1 is connected to another terminal of the resistor RDS, another terminal of the parasitic capacitor C1 is connected to the terminal of the unidirectional conducting module G, and another terminal of the unidirectional conducting module G is connected to the negative electrode of the battery P2.

In the embodiment of the present invention, when the voltage of the battery P2 is applied to the MOSFET Q1, the battery P2 starts to charge the parasitic capacitor C1, the parasitic capacitor C1 needs to reach fixed charge, and the MOSFET Q1 is turned on, similarly, when the reverse voltage is generated inside the battery P2 or in the loop where the battery P2 is located, the parasitic capacitor C1 is needed to discharge all the charge, and the MOSFET Q1 is turned off.

Since excessive charging current from the parasitic capacitor C1 may damage the MOSFET Q1, the th current limiting module L1 is provided, but if a reverse voltage is generated inside the battery pack P2 or in a loop where the battery pack P2 is located, the th current limiting module L1 may limit the turn-off speed of the MOSFET Q1.

If the unidirectional turn-on module G 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 th current-limiting module L1, the parasitic capacitor C1 and the on-resistance RDS form a discharge loop of the parasitic capacitor C1, and the off-time t of the MOSFET Q1 can be determined by the following expression:

t＝C1(RDS+R₀) (1)

wherein C1 is the capacitance of parasitic capacitance of MOSFET Q1, R₀It is known that the resistance of the current limiting module L1 at limits the turn-off speed of the MOSFET Q1.

Referring to fig. 3, due to the existence of the unidirectional module G, and the current direction of the unidirectional module G is from the other end of the unidirectional module G to the end of the unidirectional module G, 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 unidirectional module G, the parasitic capacitor C1 and the on-resistance RDS form a discharge loop of the parasitic capacitor C1, and the off-time t of the MOSFET Q1 can be determined by the following expression:

t＝C1×RDS (2)

due to the existence of the unidirectional conduction module G, a reverse voltage generated inside the battery pack P2 or in a loop where the battery pack P2 is located forms a back voltage at two ends of the parasitic capacitor C1 through the unidirectional conduction module G, so that the influence of the th current-limiting module L1 on the off time of the MOSFET Q1 is avoided, and the discharge of the parasitic capacitor C1 is accelerated.

Under the normal condition, the resistance value of the current-limiting module L1 is far larger than the resistance value RDS of the on-resistance of the MOSFET Q1, as can be seen from the expressions (1) and (2), the off-time of the MOSFET Q1 is greatly reduced by utilizing the unidirectional turn-on module G, so that the off-speed of the MOSFET Q1 is increased, the reverse voltage generated in the loop in which the battery pack P2 or the battery pack P2 is located is quickly prevented, and the load is effectively protected from the reverse voltage of the battery pack P2.

Fig. 4 is a schematic structural diagram of a circuit for preventing reverse voltage according to a second embodiment of the present invention, and fig. 4 shows specific structures of a unidirectional conducting module G and an th current limiting module L1.

As shown in fig. 4, the unidirectional turn-on module G includes a diode D1, an anode of the diode D1 is connected to a cathode of the battery P2, and a cathode of the diode D1 is connected to a gate of the MOSFET Q1. If a reverse voltage is generated in the battery pack P2 or in a loop where the battery pack P2 is located, the battery pack P2, the diode D1, the parasitic capacitor C1 and the on-resistance RDS form a discharging loop of the parasitic capacitor C1, and a reverse voltage generated in the battery pack P2 or in the loop where the battery pack P2 is located forms a back voltage at two ends of the parasitic capacitor C1 through the diode D1, so that the discharging of the parasitic capacitor C1 is accelerated, the disconnection speed of the MOSFET Q1 is accelerated, and the reverse voltage of the battery pack P2 is quickly prevented.

With continued reference to fig. 4, the th current limiting module L1 includes a resistor network N1. having a terminal of a resistor network N1 connected to the gate of the MOSFET Q1, and another terminal of the resistor network N1 connected to the negative terminal of the battery P2 and the load.

As specific examples, the resistor network N1 includes a resistor R1, a terminal of the resistor R1 is connected to the gate of the MOSFET Q1, and another terminal of the resistor R1 is connected to the negative 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 prevention circuit in fig. 5 is different from the reverse voltage prevention circuit in fig. 4 in that the reverse voltage prevention circuit in fig. 5 further includes a switching module K, a driving power supply P1, and a pull-down module M.

The th end of the switch module K is connected with a driving power supply P1, the second end of the switch module K is connected with the grid electrode of the MOSFET Q1, the third end of the switch module K is connected with the negative electrode of the battery pack P2, the driving power supply P1 is used for providing driving voltage for the switch module K so as to drive the switch module K to be in a closed state, and the pull-down module M is arranged between the th end of the switch module K and the negative electrode of the battery pack P2.

After the MOSFET Q1 is powered by the battery pack P2, the parasitic capacitance C1 of the MOSFET Q1 is charged by the battery pack P2. After the parasitic capacitor C1 starts to charge, the driving power source P1 drives the switch module K to be in a closed state. Because the switch module K is in the closed state, the charging current of the parasitic capacitor C1 is increased, so that the charging speed of the parasitic capacitor C1 is increased, and the on-time of the MOSFET Q1 is reduced. That is, the closing of the switch module K may increase the turn-on speed of the MOSFET Q1.

The embodiment of the present invention provides a pull-down module M for preventing the switch module K from being affected by noise signals, and when the input signal at the th end of the switch module K is not determined, effective grounding can be realized.

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 in fig. 6 is different from the reverse voltage prevention circuit in fig. 5 in that the reverse voltage prevention circuit in fig. 5 shows a schematic configuration diagram of the switching module K and the pull-down module M.

Referring to fig. 6, the switch module K includes a transistor Q2, the th terminal of the switch module K is a base of a transistor Q2, the second terminal of the switch module K is a collector of a transistor Q2, and the third terminal of the switch module K is an emitter of a transistor Q2, that is, the base of the transistor Q2 is connected to the driving power source P1, the collector of a transistor Q2 is connected to a gate of a MOSFET Q1, and the emitter of the transistor Q2 is connected to a cathode of a battery P2.

After the MOSFET Q1 is powered by the battery pack P2, the parasitic capacitance C1 of the MOSFET Q1 is charged by the battery pack P2. When the parasitic capacitor C1 starts to charge, the driving power source P1 drives the transistor Q2 to conduct. Due to the fact that the triode Q2 is conducted, the charging current of the parasitic capacitor C1 can be increased, the charging speed of the parasitic capacitor C1 is increased, and the conducting speed of the MOSFET Q1 is increased.

With continued reference to fig. 6, the pull-down module M includes a resistor network N2, wherein a terminal of the resistor network N2 is connected to the base of the transistor Q2, and another terminal of the resistor network N2 is connected to the negative terminal of the battery P2. as a specific example of , the resistor network N2 includes a pull-down resistor R2, a terminal of the pull-down resistor R2 is connected to the base of the transistor Q2, and another terminal of the pull-down resistor R2 is connected to the negative terminal of the battery P2.

The embodiment of the utility model provides an in, can prevent that triode Q2 from receiving noise signal's influence and producing the malfunction through setting up pull-down resistance R2, make ending of triode more reliable.

Fig. 7 shows a schematic diagram of a reverse voltage prevention circuit according to a fifth embodiment of the present invention, the reverse voltage prevention circuit in fig. 7 is different from the reverse voltage prevention circuit in fig. 6 in that fig. 7 shows exemplary structures of a driving power source P1.

Referring to fig. 7, the driving power source P1 is a battery pack P2. The base electrode of the triode Q2 is connected with the anode of the battery pack P2.

By using the battery pack P2 as the driving power supply P1 of the triode Q2, the structure of the circuit is simplified, and the cost is reduced.

Fig. 8 is a schematic diagram illustrating a structure of a reverse voltage prevention circuit according to a sixth embodiment of the present invention, the reverse voltage prevention circuit of fig. 8 is different from the reverse voltage prevention circuit of fig. 6 in that fig. 8 illustrates another exemplary structures of a driving power source P1.

Referring to fig. 8, the driving power source P1 is a power chip powered by the battery pack P2, wherein a terminal of the power chip is connected to the positive electrode of the battery pack P2, and another terminal of the power chip is connected to the base of the transistor Q2.

By using the power chip supplied with power by the battery pack P2 as the driving power P1 of the triode Q2, the driving voltage of the triode Q2 can be conveniently and flexibly set, and the application range is more .

In the embodiments of the present invention, the power chip in fig. 8 may not be powered by the battery pack P2, and may have an independent power supply.

In the utility model discloses an some embodiments, too big in order to prevent triode Q2's input current, lead to damaging triode Q2, the utility model provides a prevent reverse voltage's circuit is still including setting up the second current limiting module between the th end of drive power supply P1 and switch module K.

Fig. 9 is a schematic diagram illustrating a reverse voltage prevention circuit according to a seventh embodiment of the present invention. The reverse voltage preventing circuit of fig. 9 is different from the reverse voltage preventing circuit of fig. 7 in that the reverse voltage preventing circuit of fig. 9 shows a specific structure of the second current limiting module.

As shown in fig. 9, the second current limiting module includes a resistor network N3, wherein a terminal of the resistor network N3 is connected to the positive terminal of the battery P2, and another terminal of the resistor network N3 is connected to the base of the transistor Q2. with continued reference to fig. 9, the resistor network N3 includes a resistor R3, a terminal of the resistor R3 is connected to the positive terminal of the battery P2, and another terminal of the resistor R3 is connected to the base of the transistor Q2.

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. 9 in that the reverse voltage prevention circuit of fig. 10 includes an overvoltage protection module E disposed between the source of the MOSFET Q1 and the terminal of the current limiting module L1, the overvoltage protection module E is used to provide overvoltage protection for the MOSFET Q1, preventing the MOSFET Q1 from being damaged due to an excessively high voltage between its gate and source.

As an example, with continued reference to FIG. 10, the overvoltage protection module E includes a diode D2, an anode of the diode D2 is connected to the terminal of the resistor R1, and a cathode of the diode D2 is connected to the source of the MOSFET Q1. the diode D2 may be a clamp diode.

Fig. 11 shows a reverse voltage prevention circuit according to a ninth embodiment of the present invention. The reverse voltage prevention circuit in fig. 11 is different from the reverse voltage prevention circuit in fig. 10 in that the reverse voltage prevention circuit in fig. 11 further includes a capacitor C2 disposed between the anode of the battery P2 and the cathode of the battery P2, and a capacitor C3 disposed between the source of the MOSFET Q1 and the cathode of the battery P2.

In the embodiment of the utility model, can filter the too high voltage of transient state through setting up electric capacity C2 and electric capacity C3 to advance step better protection MOSFET Q1.

The scope of the present invention is not limited thereto, and various equivalent modifications or substitutions which are within the skill of those skilled in the art can be easily conceived and reduced to the extent of the present disclosure are intended to be included within the scope of the present disclosure.

Claims

1, A reverse voltage prevention circuit, comprising:

the th current limiting module and the th current limiting module are connected at the other end with the negative pole of the battery pack and the load.

2. The circuit of claim 1, wherein the unidirectional conducting module comprises an th diode, an anode of the th diode is connected to a cathode of the battery pack, and a cathode of the th diode is connected to a gate of the MOSFET.

3. The circuit of claim 1, further comprising:

a th end of the switch module is connected with a driving power supply, a second end of the switch module is connected with the grid electrode of the MOSFET, and a third end of the switch module is connected with the negative electrode of the battery pack;

4. The circuit of claim 3, wherein the switch module comprises a transistor, the th terminal of the switch module is a base of the transistor, the second terminal of the switch module is a collector of the transistor, and the third terminal of the switch module is an emitter of the transistor.

5. The circuit of claim 3, further comprising:

6. The circuit of claim 5, wherein the second current limiting module comprises an th resistor network, wherein a terminal of the th resistor network is connected to the driving power source, and a terminal of the th resistor network is connected to a terminal of the switch module.

7. The circuit of claim 3, wherein the pull-down module comprises a second resistor network, wherein terminal of the second resistor network is connected to terminal of the switch module, and wherein terminal of the second resistor network is connected to the negative terminal of the battery pack.

8. The circuit of claim 3, wherein the driving power source is the battery pack, and the th terminal of the switch module is connected to the positive electrode of the battery pack.

9. The circuit of claim 3, wherein the driving power source is a power chip powered by the battery pack, wherein a terminal of the power chip is connected to the positive electrode of the battery pack, and another terminal of the power chip is connected to the terminal of the switch module.

10. The circuit of claim 1, further comprising:

11. The circuit of claim 10, wherein the overvoltage protection module comprises:

a second diode having an anode connected to the terminal of the current limiting module and a cathode connected to the source of the MOSFET.

12. The circuit of claim 1, further comprising:

an th capacitor disposed between the positive electrode of the battery and the negative electrode of the battery;

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