CN219999096U

CN219999096U - Switching circuit and automobile power grid system

Info

Publication number: CN219999096U
Application number: CN202320293330.9U
Authority: CN
Inventors: 吴航
Original assignee: United Automotive Electronic Systems Co Ltd
Current assignee: United Automotive Electronic Systems Co Ltd
Priority date: 2023-02-22
Filing date: 2023-02-22
Publication date: 2023-11-10
Anticipated expiration: 2033-02-22

Abstract

The utility model provides a switching circuit and an automobile power grid system, wherein the switching circuit comprises a cooling starting bridge circuit and a main bridge circuit, the cooling starting bridge circuit comprises a first resistor and a first switching unit, and the first switching unit and the first resistor are connected in series and then connected between a first node and a second node; the main bridge circuit comprises a second resistor, a second switch unit and a voltage clamping unit, one end of the second resistor is connected with the first node, and the second switch unit and the voltage clamping unit are connected in parallel and then connected between the other end of the second resistor and the second node. When the reverse connection condition occurs because the power grid accessed by any one of the first node and the second node is not the power grid corresponding to the power grid, the voltage clamping unit clamps the reverse voltage within the specified voltage range, the voltage at the two ends of the cooling starting bridge circuit can be ensured to be almost consistent with the short-circuit working condition, and the first resistor can not be burnt out due to the overcurrent working condition in the process of periodically closing the first switch unit.

Description

Switching circuit and automobile power grid system

Technical Field

The utility model relates to the technical field of automobiles, in particular to a switching circuit and an automobile power grid system.

Background

The intelligent power grid management module (PNG) is mainly applied to an intelligent power grid of an automatic driving vehicle with functional safety requirements, and is mainly used for monitoring the state of the power grid and controlling connection or disconnection of the power grid on two sides of the PNG. For example, the battery can be charged and discharged during connection, and mutual interference between power grids at two sides can be avoided during disconnection. When one side power grid fails, the power grids at the two sides of the PNG are disconnected, so that the power grids at the two sides are prevented from failing, and for the PNG with the power grids at the two sides, NMOS (N-channel metal oxide semiconductor) tubes connected back to back are needed to be used as switches to prevent leakage currents in two directions.

Specifically, referring to fig. 1, fig. 1 is a schematic diagram of a switch circuit of a smart grid management module in the prior art, including a protection diode D0, a first resistor R01, a second resistor R02, and first to fourth NMOS transistors, a drain electrode of the first NMOS transistor T1 is connected to a first circuit endpoint K1 through the first resistor R01, a source electrode of the first NMOS transistor T1 is connected to a source electrode of the second NMOS transistor T2, a drain electrode of the second NMOS transistor T2 is connected to a second circuit endpoint K2, a source electrode of the third NMOS transistor T3 is connected to the first circuit endpoint K1 through the second resistor R02, a drain electrode of the third NMOS transistor T3 and a drain electrode of the fourth NMOS transistor T4 are connected to ground through the protection diode D0, a forward direction of the protection diode D0 is grounded, and a source electrode of the fourth NMOS transistor is connected to the second circuit endpoint.

Typically, the first circuit terminal K1 and the second circuit terminal K2 are connected to separate power grids, for example, the first circuit terminal K1 is connected to an output terminal of the DCDC circuit or an output terminal of the DCDC booster, and the second circuit terminal K2 is connected to a positive terminal of the storage battery. When PNG works normally, the first NMOS tube to the fourth NMOS tube are all conducted. When one of the circuit terminals is connected to the power grid corresponding to the other circuit terminal, such as the first circuit terminal K1 is connected to the positive terminal of the storage battery, PNG will enter an overcurrent state due to a short circuit, the voltage difference between the two ends of the switch circuit will reach twice Vbat (Vbat is the voltage of the storage battery), at this time, the switch circuit will trigger an overcurrent protection mechanism, the third NMOS tube T3 and the fourth NMOS tube T4 will be turned off, the first NMOS tube T1 and the second NMOS tube T2 will be periodically and simultaneously turned on after being turned off, and the voltage difference between the first circuit terminal K1 and the second circuit terminal K2 is twice Vbat due to the reverse connection of the circuit terminals, at this time, the first resistor (i.e. the shunt resistor) in the circuit will be burned out due to the overlarge current.

Disclosure of Invention

The utility model aims to provide a switching circuit and an automobile power grid system, which are used for solving the problem that shunt resistance is burnt out due to overcurrent when the switching circuit in a smart power grid management module is in reverse connection.

In order to solve the above technical problem, according to one aspect of the present utility model, there is provided a switching circuit, comprising:

the cooling starting bridge circuit comprises a first resistor and a first switch unit, wherein the first switch unit and the first resistor are connected in series and then connected between a first node and a second node;

the main bridge circuit comprises a second resistor, a second switch unit and a voltage clamping unit, wherein one end of the second resistor is connected to the first node, and the second switch unit and the voltage clamping unit are connected in parallel and then connected between the other end of the second resistor and the second node;

when one of the first node and the second node is connected to a power grid corresponding to the other node, the first switch unit is periodically closed, the second switch unit is opened, and the voltage clamping unit clamps the voltage of the first node or the voltage of the second node within a specified voltage range.

Optionally, the first switch unit includes a first power tube and a second power tube, an input end of the first power tube is connected to the first node through the first resistor, an output end of the first power tube is connected to an output end of the second power tube, and an input end of the second power tube is connected to the second node.

Optionally, the types of the first power tube and the second power tube are NMOS tubes, the respective input ends of the first power tube and the second power tube are drains of the NMOS tubes, and the respective output ends of the first power tube and the second power tube are sources of the NMOS tubes.

Optionally, the second switch unit includes a third power tube and a fourth power tube, an output end of the third power tube is connected with the second resistor, an input end of the third power tube is connected with an input end of the fourth power tube, and an output end of the fourth power tube is connected with the second node.

Optionally, the types of the third power tube and the fourth power tube are NMOS tubes, the respective input ends of the third power tube and the fourth power tube are drains of the NMOS tubes, and the respective output ends of the third power tube and the fourth power tube are sources of the NMOS tubes.

Optionally, the cooling starting bridge further includes a first diode, the input end of the third power tube and the input end of the fourth power tube are connected with the reverse end of the first diode, and the forward end of the first diode is grounded.

Optionally, the voltage clamping unit includes a voltage clamping element, a fifth power tube and a sixth power tube, the input end of the fifth power tube is connected to the second resistor, the output end of the fifth power tube and the output end of the sixth power tube are connected and then commonly grounded through the voltage clamping element, and the input end of the sixth power tube is connected to the second node; the fifth power tube and the sixth power tube are respectively provided with a body diode which is reversed and is arranged between the input end and the output end of each power tube so as to clamp the voltage of the first node or the voltage of the second node in cooperation with the voltage clamping element.

Optionally, the fifth power tube and the sixth power tube are NMOS tubes, the respective input ends of the fifth power tube and the sixth power tube are drains of the NMOS tubes, and the respective output ends of the fifth power tube and the sixth power tube are sources of the NMOS tubes.

Optionally, the voltage clamping element includes a second diode, a reverse end of the second diode is connected to the output end of the fifth power tube and the output end of the sixth power tube, and a forward end of the second diode is grounded.

In order to solve the technical problem, based on another aspect of the present utility model, the present utility model further provides an automotive power grid system, which includes a smart power grid management module, a first power grid and a second power grid, where the smart power grid management module has the switch circuit as described above, the power grid to which the first node is correspondingly connected is the first power grid, and the power grid to which the second node is correspondingly connected is the second power grid.

In summary, in the switch circuit and the automobile power grid system provided by the utility model, the switch circuit comprises a cooling start bridge circuit and a main bridge circuit, the cooling start bridge circuit comprises a first resistor and a first switch unit, and the first switch unit and the first resistor are connected in series and then connected between a first node and a second node; the main bridge circuit comprises a second resistor, a second switch unit and a voltage clamping unit, wherein one end of the second resistor is connected with the first node, and the second switch unit and the voltage clamping unit are connected in parallel and then connected between the other end of the second resistor and the second node; when one of the first node and the second node is connected to a power grid corresponding to the other node, the first switch unit is periodically closed, the second switch unit is opened, and the voltage clamping unit clamps the voltage of the first node or the voltage of the second node within a specified voltage range.

When the reverse connection condition occurs because the power grid accessed by any one of the first node and the second node is not the power grid corresponding to the power grid, the configuration of the voltage clamping unit can clamp the reverse voltage within a specified voltage range, the voltage at two ends of the cooling starting bridge circuit can be ensured to be almost consistent with a short-circuit working condition, and the first resistor can not be burnt out due to the overcurrent working condition in the process of periodically closing the first switch unit.

It should be noted that, since the automotive power grid system has the switching circuit, there is also an advantageous technical effect brought by the switching circuit, and the technical effect of the automotive power grid system is not explained here.

Drawings

It will be appreciated by those skilled in the art that the drawings are provided for a better understanding of the utility model and do not constitute any limitation on the scope of the utility model. Wherein:

FIG. 1 is a schematic diagram of a switching circuit of a prior art smart grid management module;

fig. 2 is a schematic diagram of a switching circuit according to an embodiment of the utility model.

In the accompanying drawings:

t1-a first NMOS tube; t2-a second NMOS tube; t3-a third NMOS tube; t4-a fourth NMOS tube; d0—a protection diode; k1-a first circuit endpoint; k2-a second circuit endpoint; r01-a first resistor; r02-a second resistor;

10-cooling the start-up bridge; r1-a first resistor; s1-a first switch unit; q1-a first power tube; q2-a second power tube;

20-a main bridge; r2-a second resistor; s2-a second switch unit; q3-a third power tube; q4-a fourth power tube; d1-a first diode; 200-a voltage clamping unit; q5-a fifth power tube; q6-a sixth power tube; d2—a second diode; d3-a third diode; d4—fourth diode;

n1-a first node; n2-second node.

Detailed Description

The utility model will be described in further detail with reference to the drawings and the specific embodiments thereof in order to make the objects, advantages and features of the utility model more apparent. It should be noted that the drawings are in a very simplified form and are not drawn to scale, merely for convenience and clarity in aiding in the description of embodiments of the utility model. Furthermore, the structures shown in the drawings are often part of actual structures. In particular, the drawings are shown with different emphasis instead being placed upon illustrating the various embodiments.

As used in this disclosure, the singular forms "a," "an," and "the" include plural referents, the term "or" are generally used in the sense of comprising "and/or" and the term "several" are generally used in the sense of comprising "at least one," the term "at least two" are generally used in the sense of comprising "two or more," and the term "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying any relative importance or number of features indicated. Thus, a feature defining "first," "second," "third," or "third" may explicitly or implicitly include one or at least two such features, with "one end" and "another end" and "proximal end" and "distal end" generally referring to the respective two portions, including not only the endpoints, but also the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, e.g., as being either a fixed connection, a removable connection, or as being integral therewith; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. Furthermore, as used in this disclosure, an element disposed on another element generally only refers to a connection, coupling, cooperation or transmission between two elements, and the connection, coupling, cooperation or transmission between two elements may be direct or indirect through intermediate elements, and should not be construed as indicating or implying any spatial positional relationship between the two elements, i.e., an element may be in any orientation, such as inside, outside, above, below, or on one side, of the other element unless the context clearly indicates otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Fig. 2 is a schematic diagram of a switching circuit according to an embodiment of the utility model. As shown in fig. 2, an embodiment of the present utility model schematically provides a switching circuit applied to a smart grid management module, the switching circuit includes a cooling start bridge 10 and a main bridge 20, and the cooling start bridge 10 and the main bridge 20 are connected in parallel to each other and then connected between a first node N1 and a second node N2. The cooling start bridge 10 includes a first resistor R1 and a first switch unit S1, where the first switch unit S1 and the first resistor R1 are connected in series and then connected between a first node N1 and a second node N2, specifically, one end of the first switch unit S1 may be connected to the first node N1 through the first resistor R1, and the other end of the first switch unit S1 is connected to the second node N2, so, when the first switch unit S1 is closed, the circuit state of the cooling start bridge 10 is an on-way, and when the first switch unit S1 is opened, the circuit state of the cooling start bridge 10 is an off-way. The main bridge 20 includes a second resistor R2, a second switch unit S2, and a voltage clamping unit 200, where one end of the second resistor R2 is connected to the first node N1, and the second switch unit S2 and the voltage clamping unit 200 are connected in parallel to each other and then connected between the other end of the second resistor R2 and the second node N2, so that when the second switch unit S2 is closed, the circuit state of the main bridge 20 is on, and when the second switch unit S2 is opened, the circuit state of the main bridge 20 is off. It should be noted that, the power grids correspondingly connected to the first node N1 and the second node N2 are different, for example, the power grid correspondingly connected to the first node N1 is a first power grid, for example, the first power grid may be a DCDC circuit, the first node N1 is connected to the output end of the DCDC conversion circuit, the second power grid may be a battery of an automobile, for example, and the second node N2 is connected to the positive end of the battery. When one of the first node N1 and the second node N2 is connected to the power grid corresponding to the other node, for example, the first node N1 and the second node N2 are connected to the positive terminal of the storage battery, the first switch unit S1 is periodically closed, the second switch unit S2 is opened, and the voltage clamping unit 200 clamps the voltage of the first node N1 or the voltage of the second node N2 within a specified voltage range, where the numerical configuration of the specified voltage range is such that the voltage at both ends of the cooling start bridge 10 is almost the same as the voltage represented when the cooling start bridge 10 is in a short circuit state. In one embodiment, the specified voltage range is within 2V. So configured, when the reverse connection condition occurs because the power grid accessed by any one of the first node N1 and the second node N2 is not the power grid corresponding to itself, the configuration of the voltage clamping unit 200 can clamp the reverse voltage within the specified voltage range, at this time, the voltages at two ends of the cooling start bridge circuit 10 can be ensured to be almost consistent with the short-circuit condition, and the first resistor R1 is ensured not to be burnt out due to the occurrence of the overcurrent condition in the process of periodically closing the first switch unit S1, so that the normal operation of the cooling start bridge circuit 10 is ensured.

Further, the first switch unit S1 includes a first power tube Q1 and a second power tube Q2 connected back-to-back, specifically, an input end of the first power tube Q1 is connected to the first node N1 through a first resistor R1, an output end of the first power tube Q1 is connected to an output end of the second power tube Q2, and an input end of the second power tube Q2 is connected to the second node N2. Thus, when the first power tube Q1 and the second power tube Q2 are both turned on, the first switch unit S1 is turned on, and when the first power tube Q1 and the second power tube Q2 are both turned off, the first switch unit S1 is turned off. For example, the first power tube Q1 and the second power tube Q2 are NMOS tubes, the respective input ends of the first power tube Q1 and the second power tube Q2 are drains of the NMOS tubes, and the respective output ends of the first power tube Q1 and the second power tube Q2 are sources of the NMOS tubes.

Further, the second switching unit S2 includes a third power tube Q3 and a fourth power tube Q4 connected face-to-face, specifically, an output end of the third power tube Q3 is connected to the second resistor R2, an input end of the third power tube Q3 is connected to an input end of the fourth power tube Q4, and an output end of the fourth power tube Q4 is connected to the second node N2. In this way, when the third power tube Q3 and the fourth power tube Q4 are both turned on, the second switch unit S2 is turned on, and when the third power tube Q3 and the fourth power tube Q4 are both turned off, the second switch unit S2 is turned off. For example, the third power transistor Q3 and the fourth power transistor Q4 are NMOS transistors, the respective input ends of the third power transistor Q3 and the fourth power transistor Q4 are drains of the NMOS transistors, and the respective output ends of the third power transistor Q3 and the fourth power transistor Q4 are sources of the NMOS transistors.

Preferably, the cooling start bridge 10 further includes a first diode D1, the input terminal of the third power tube Q3 and the input terminal of the fourth power tube Q4 are connected to the reverse terminal of the first diode D1, and the forward terminal of the first diode D1 is grounded. It can be understood that the action switching between the synchronous on and off of the third power tube Q3 and the fourth power tube Q4 corresponds to the action switching of the on and off of the second switch unit S2, so, when the action switching of the second switch unit S2 results in the positive or negative pulse voltage, the voltage can be clamped by the configuration of the first diode D1, and the safety is ensured.

Further, the voltage clamping unit 200 includes a voltage clamping element, a fifth power tube Q5 and a sixth power tube Q6, where the fifth power tube Q5 and the sixth power tube Q6 are connected back to back, specifically, an input end of the fifth power tube Q5 is connected to the second resistor R2, and an output end of the fifth power tube Q5 and an output end of the sixth power tube Q6 are connected to each other and then are commonly grounded through the voltage clamping element, and an input end of the sixth power tube Q6 is connected to the second node N2; the fifth power transistor Q5 and the sixth power transistor Q6 each have a body diode inverted between respective input terminals and output terminals to clamp the voltage of the first node N1 or the voltage of the second node N2 in cooperation with the voltage clamping element. It should be noted that, when the first node N1 or the second node N2 has a reverse connection, both the fifth power transistor Q5 and the sixth power transistor Q6 are turned off. Referring to fig. 2, the body diode of the fifth power transistor Q5 is a third diode D3, and the body diode of the sixth power transistor Q6 is a fourth diode D4. In an embodiment, the voltage clamping element includes a second diode D2, a reverse end of the second diode D2 is connected to the output end of the fifth power transistor Q5 and the output end of the sixth power transistor Q6, and a forward end of the second diode D2 is grounded. In this way, voltage clamping can be achieved by the forward voltage drop of the second diode D2, the third diode D3, and the fourth diode D4, and the voltage can be clamped within 2V.

For example, the fifth power tube Q5 and the sixth power tube Q6 are NMOS tubes, the input ends of the fifth power tube Q5 and the sixth power tube Q6 are drains of the NMOS tubes, and the output ends of the fifth power tube Q5 and the sixth power tube Q6 are sources of the NMOS tubes. In other embodiments, the fifth power transistor Q5 and the sixth power transistor Q6 may be IGBT transistors.

It can be understood that the third power tube Q3 and the fourth power tube Q4 are connected face to face, and the fifth power tube Q5 and the sixth power tube Q6 are connected back to back, so that the intelligent power grid management module can support bidirectional power supply operation.

It should be noted that, the on or off of the first to sixth power transistors Q6 may be controlled by the MCU of the automobile power grid system, where the MCU sends a control signal to the driving end of the power transistor to control the on or off of the power transistor, for example, sends a high level to the gate of the NMOS transistor to turn on the NMOS transistor, and sends a low level to the gate of the NMOS transistor to turn off the NMOS transistor.

Based on the above-mentioned switch circuit, the embodiment further provides an automobile power grid system, which includes a smart power grid management module (PNG), a first power grid and a second power grid, where the smart power grid management module has the switch circuit as described above, and the first node N1 is correspondingly connected to the first power grid, and the second node N2 is correspondingly connected to the second power grid. The first electrical network may be, for example, a DCDC circuit, and the second electrical network may be, for example, a battery.

When the intelligent power grid management module is in a normal working state, the first switch unit S1 is continuously closed, the second switch unit S2 is continuously closed, and the fifth power tube Q5 and the sixth power tube Q6 are both conducted. When the smart grid management module fails or detects a grid fault (first grid and/or second grid fault), the second switch unit S2 is turned off, the fifth power tube Q5 and the sixth power tube Q6 are both turned off, the first switch unit S1 is turned off and then periodically turned on, and if the circuit is still in an overcurrent state after being periodically turned on for a period of time, the first switch unit S1 is driven to be continuously turned off.

The foregoing description is only illustrative of the preferred embodiments of the present utility model, and is not intended to limit the scope of the present utility model in any way, and any changes and modifications made by those skilled in the art in light of the foregoing disclosure will be deemed to fall within the scope and spirit of the present utility model.

Claims

1. A switching circuit for a smart grid management module, comprising:

the cooling starting bridge circuit (10) comprises a first resistor (R1) and a first switch unit (S1), wherein the first switch unit (S1) and the first resistor (R1) are connected in series and then connected between a first node (N1) and a second node (N2);

the main bridge circuit (20) comprises a second resistor (R2), a second switching unit (S2) and a voltage clamping unit (200), wherein one end of the second resistor (R2) is connected to the first node (N1), and the second switching unit (S2) and the voltage clamping unit (200) are connected in parallel and then connected between the other end of the second resistor (R2) and the second node (N2);

when one of the first node (N1) and the second node (N2) is connected to a power grid corresponding to the other node, the first switch unit (S1) is periodically closed, the second switch unit (S2) is opened, and the voltage clamping unit (200) clamps the voltage of the first node (N1) or the voltage of the second node (N2) within a specified voltage range.

2. The switching circuit according to claim 1, wherein the first switching unit (S1) comprises a first power tube (Q1) and a second power tube (Q2), an input end of the first power tube (Q1) is connected to the first node (N1) through the first resistor (R1), an output end of the first power tube (Q1) is connected to an output end of the second power tube (Q2), and an input end of the second power tube (Q2) is connected to the second node (N2).

3. The switching circuit according to claim 2, wherein the first power tube (Q1) and the second power tube (Q2) are NMOS tubes, the respective input ends of the first power tube (Q1) and the second power tube (Q2) are drains of the NMOS tubes, and the respective output ends of the first power tube (Q1) and the second power tube (Q2) are sources of the NMOS tubes.

4. The switching circuit according to claim 1, wherein the second switching unit (S2) comprises a third power tube (Q3) and a fourth power tube (Q4), an output terminal of the third power tube (Q3) is connected to the second resistor (R2), an input terminal of the third power tube (Q3) is connected to an input terminal of the fourth power tube (Q4), and an output terminal of the fourth power tube (Q4) is connected to the second node (N2).

5. The switching circuit according to claim 4, wherein the third power tube (Q3) and the fourth power tube (Q4) are NMOS tubes, the respective input ends of the third power tube (Q3) and the fourth power tube (Q4) are drains of the NMOS tubes, and the respective output ends of the third power tube (Q3) and the fourth power tube (Q4) are sources of the NMOS tubes.

6. The switching circuit according to claim 4, wherein the cooling start-up bridge (10) further comprises a first diode (D1), the input of the third power tube (Q3) and the input of the fourth power tube (Q4) are connected to the reverse side of the first diode (D1), and the forward side of the first diode (D1) is grounded.

7. The switching circuit according to claim 1, wherein the voltage clamping unit (200) comprises a voltage clamping element, a fifth power tube (Q5) and a sixth power tube (Q6), an input end of the fifth power tube (Q5) is connected to the second resistor (R2), an output end of the fifth power tube (Q5) and an output end of the sixth power tube (Q6) are connected to be commonly grounded through the voltage clamping element, and an input end of the sixth power tube (Q6) is connected to the second node (N2); the fifth power tube (Q5) and the sixth power tube (Q6) are respectively provided with a body diode which is inverted and is arranged between the input end and the output end of each power tube so as to clamp the voltage of the first node (N1) or the voltage of the second node (N2) in cooperation with the voltage clamping element.

8. The switching circuit according to claim 7, wherein the fifth power transistor (Q5) and the sixth power transistor (Q6) are NMOS transistors, the input ends of the fifth power transistor (Q5) and the sixth power transistor (Q6) are drains of the NMOS transistors, and the output ends of the fifth power transistor (Q5) and the sixth power transistor (Q6) are sources of the NMOS transistors.

9. The switching circuit according to claim 7, wherein the voltage clamping element comprises a second diode (D2), a reverse terminal of the second diode (D2) being connected to the output terminal of the fifth power transistor (Q5) and the output terminal of the sixth power transistor (Q6), and a forward terminal of the second diode (D2) being grounded.

10. An automotive power grid system, characterized by comprising a smart power grid management module, a first power grid and a second power grid, the smart power grid management module having a switching circuit according to any one of claims 1 to 9, the power grid to which the first node (N1) is connected in correspondence being the first power grid, and the power grid to which the second node (N2) is connected in correspondence being the second power grid.