Relay rear-end protection circuit and vehicle-mounted controller

Abstract

The utility model discloses a relay rear-end protection circuit and a vehicle-mounted controller, the relay rear-end protection circuit comprises a high-side circuit, a relay and a low-side driving circuit, the high-side circuit comprises a high-voltage power supply and a load, the high-voltage power supply and the relay are both connected with the load, and the low-side driving circuit is connected with the relay; wherein when the low-side driving circuit controls the relay to be closed, the load is in a working state; and when the low-side driving circuit controls the relay to be disconnected, the load loop is in a disconnected state to prevent the load from working for a long time. Potential safety hazards caused by long-time work of the load can be effectively avoided, and the service life of the power device can be prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicles, in particular to a relay rear end protection circuit and a vehicle-mounted controller. Background Art

[0002] As the demand for automobile functions becomes higher and higher, the safety requirements for in-car control devices are also gradually increasing. Currently, common power device control devices such as window anti-pinch controllers, glass lift controllers, seat controllers, and sunroof controllers all use high effective output to control whether the load is working.

[0003] At present, the common high-effective output methods are divided into three types: high-side driver chips, low-side driver chips with relays, and MOS (Metal Oxide Semiconductor) tube control chips with MOS tubes to form an H-bridge. After long-term use, all of them may cause output adhesion, and the inductive and resistive loads at the back end will heat up and catch fire due to long-term work, affecting personnel safety. Utility Model Content

[0004] The utility model aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the first purpose of the utility model is to provide a relay back-end protection circuit, which can effectively avoid safety hazards caused by long-term operation of the load and extend the service life of the power device.

[0005] The second purpose of the utility model is to provide a vehicle-mounted controller.

[0006] In order to achieve the above object, the utility model is implemented through the following technical solutions:

[0007] A relay back-end protection circuit comprises: a high-side circuit, a relay and a low-side drive circuit, wherein the high-side circuit comprises a high-voltage power supply and a load, the high-voltage power supply and the relay are both connected to the load, and the low-side drive circuit is connected to the relay; wherein when the low-side drive circuit controls the relay to be attracted, the load is in a working state; and when the low-side drive circuit controls the relay to be disconnected, the load circuit is in a disconnected state to prevent the load from working for a long time.

[0008] Preferably, the relay comprises a coil and first to third contacts, the first contact and the second contact are grounded, and the third contact is connected to one end of the load.

[0009] Preferably, the high-side circuit further includes a high-drive switch, and the high-voltage power supply is connected to the other end of the load via the high-drive switch.

[0010] Preferably, the low-side driving circuit comprises a controller and a transistor, the output end of the controller is connected to the base of the transistor, the emitter of the transistor is grounded, and the collector of the transistor is connected to the coil.

[0011] Preferably, the low-side driving circuit also includes a first current limiting resistor and a second current limiting resistor, the first current limiting resistor is connected in series between the output end of the controller and the base of the transistor, and the second current limiting resistor is connected between the base and the emitter of the transistor.

[0012] Preferably, the low-side driving circuit further comprises a diode, an anode of the diode is connected to the collector of the transistor, and a cathode of the diode is connected to the coil.

[0013] Preferably, when the relay is closed, the first contact is connected to the third contact, and when the relay is opened, the first contact is connected to the second contact.

[0014] In order to achieve the above-mentioned object, the second aspect of the utility model provides a vehicle-mounted controller, including the above-mentioned relay rear-end protection circuit.

[0015] The utility model has at least the following technical effects:

[0016] The utility model comprises a high-side circuit, a relay and a low-side driving circuit, wherein the high-side circuit comprises a high-voltage power supply, a load and a high-drive switch, wherein the high-voltage power supply is connected to the load through the high-drive switch, wherein the first contact and the second contact of the relay are grounded, and the third contact is connected to the load; the low-side driving circuit comprises a controller, a transistor, a current-limiting resistor and a diode, wherein the controller is connected to the base of the transistor through the current-limiting resistor, and the collector of the transistor is connected to the coil of the relay through the diode, and when the load works for a long time and the high-drive switch is broken down as a primary protection device, the controller can also output a low-level signal to control the transistor to be turned off, thereby reducing the current on the coil, so that the first contact The contact point rebounds to the second contact point, thereby disconnecting the load circuit. The low-side drive circuit controls the relay so that the relay acts as a second protection device to prevent the load from working for a long time and causing safety hazards, and can extend the service life of the power device. In addition, based on this structure, the following strategy is adopted: when the load works normally, the high-drive switch is closed first, and then the relay is closed; when the load circuit is disconnected, the relay is controlled to be disconnected first, and then the high-drive switch is controlled to be disconnected, so as to avoid the influence of arcing on the high-side circuit devices; and when the utility model controls the relay to be disconnected, the current on the coil can be discharged through the discharge diode, thereby protecting the relay and the low-side drive device.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will become apparent from the following description or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of a relay rear end protection circuit according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0019] The present embodiment is described in detail below, and examples of the embodiment are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present utility model, and should not be construed as limiting the present utility model.

[0020] A relay rear end protection circuit and a vehicle-mounted controller of this embodiment will be described below with reference to the accompanying drawings.

[0021] Figure 1 Schematic diagram of the relay rear end protection circuit of the utility model embodiment. Figure 1 As shown, the relay back-end protection circuit includes: a high-side circuit, a relay J and a low-side drive circuit, the high-side circuit includes a high-voltage power supply E and a load, the load includes an inductive load L and a resistive load R1, the high-voltage power supply E and the relay J are both connected to the load, and the low-side drive circuit is connected to the relay J; wherein, when the low-side drive circuit controls the relay J to be attracted, the load is grounded and in a working state; when the low-side drive circuit controls the relay J to be disconnected, the load circuit is in a disconnected state to prevent the load from working for a long time. The relay back-end protection circuit can be applied to the case of multiple loads.

[0022] In this embodiment, the relay J includes a coil X and first to third contacts 1 to 3 , the first contact 1 and the second contact 2 are grounded, and the third contact 3 is connected to one end of the load.

[0023] The high-side circuit further includes a high-drive switch S, and the high-voltage power supply E is connected to the other end of the load through the high-drive switch S.

[0024] Please continue to refer to Figure 1 The low-side driving circuit includes a controller MCU and a transistor Q, the output end of the controller MCU is connected to the base of the transistor Q, the emitter of the transistor Q is grounded, and the collector of the transistor Q is connected to the coil X.

[0025] The low-side driving circuit further includes a first current limiting resistor R2 and a second current limiting resistor R3. The first current limiting resistor R2 is connected in series between the output end of the controller MCU and the base of the transistor Q. The second current limiting resistor R3 is connected between the base and the emitter of the transistor Q.

[0026] The low-side driving circuit further includes a diode D, an anode of the diode D is connected to the collector of the transistor Q, and a cathode of the diode D is connected to the coil X.

[0027] The working principle of the relay rear end protection circuit of this embodiment is:

[0028] When the load needs to work, the high-drive switch S is closed first, and then the controller MCU outputs a high-level signal to turn on the transistor Q, and current flows in the coil X of the relay J, so that the first contact 1 of the relay J is connected to the third contact 3, so that the load is grounded. At this time, the load circuit is turned on and the load is in working state. In order to avoid safety hazards caused by long-term operation of the load, the load circuit can be controlled by the first protection device, that is, the high-drive switch S. For example, when the load works for a long time, the high-drive switch S can be pressed to disconnect the load circuit. However, when the load works for a long time and the output is adhered, it may cause the high-drive switch S to break down, so that the load circuit is always in a closed state. For this reason, the controller MCU can output a low-level signal to turn off the transistor Q, reduce the current in the coil X, so that the first contact 1 rebounds to the second contact 2, the load grounding terminal is suspended, and the load circuit is disconnected. Therefore, the second-level protection of the equipment can be achieved through the second protection device, that is, the relay J, which can prevent the load from working for a long time and causing safety hazards, and extend the service life of the power device.

[0029] It should be noted that when the load circuit needs to be disconnected, based on this structure, the controller MCU can be controlled to output a low-level signal to turn off the relay J, and then the high-drive switch S is pressed to turn off, thereby avoiding the influence of arcing on the high-side circuit devices.

[0030] In addition, the utility model can protect the low-side drive device by setting a current limiting resistor in the low-side drive circuit, and can discharge the current on the coil X by setting a diode D between the transistor Q and the coil X, thereby protecting the relay and the low-side drive device.

[0031] Furthermore, the utility model also provides a vehicle-mounted controller, which includes the above-mentioned relay rear-end protection circuit.

[0032] In summary, the utility model includes a high-side circuit, a relay and a low-side drive circuit, wherein the high-side circuit includes a high-voltage power supply, a load and a high-drive switch, wherein the high-voltage power supply is connected to the load through the high-drive switch, wherein the first contact and the second contact of the relay are grounded, and the third contact is connected to the load; the low-side drive circuit includes a controller, a transistor, a current-limiting resistor and a diode, wherein the controller is connected to the base of the transistor through the current-limiting resistor, and the collector of the transistor is connected to the coil of the relay through the diode, and when the load works for a long time and the high-drive switch is broken down as a primary protection device, the controller can also output a low-level signal to control the transistor to turn off, thereby reducing the current on the coil, so that the first A contact rebounds to a second contact, thereby disconnecting the load circuit. Thus, the relay is controlled by the low-side drive circuit so that the relay acts as a second protection device to prevent the load from working for a long time and causing safety hazards, and can extend the service life of the power device. In addition, based on this structure, even if the load works normally, the high-drive switch is closed first, and then the relay is closed. When the load circuit is disconnected, the relay is controlled to be disconnected first, and then the high-drive switch is controlled to be disconnected. This can avoid the influence of arcing on the high-side circuit device. When the relay is disconnected, the current on the coil can be discharged through the discharge diode, thereby protecting the relay and the low-side drive device.

[0033] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0034] Although the content of the utility model has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the utility model. After reading the above content, various modifications and substitutions of the utility model will be obvious to those skilled in the art. Therefore, the protection scope of the utility model should be limited by the attached claims.

Claims

1. A relay back-end protection circuit, characterized in that: include: A high-side circuit, a relay and a low-side drive circuit, wherein the high-side circuit includes a high-voltage power supply and a load, the high-voltage power supply and the relay are both connected to the load, and the low-side drive circuit is connected to the relay; wherein when the low-side drive circuit controls the relay to be attracted, the load is in a working state; and when the low-side drive circuit controls the relay to be disconnected, the load circuit is in a disconnected state to prevent the load from working for a long time.

2. The relay rear end protection circuit according to claim 1, characterized in that: The relay includes a coil and first to third contacts, the first and second contacts are grounded, and the third contact is connected to one end of the load.

3. The relay rear end protection circuit according to claim 2, characterized in that: The high-side circuit further includes a high-drive switch, and the high-voltage power supply is connected to the other end of the load via the high-drive switch.

4. The relay rear end protection circuit according to claim 2, characterized in that: The low-side driving circuit comprises a controller and a transistor, wherein the output end of the controller is connected to the base of the transistor, the emitter of the transistor is grounded, and the collector of the transistor is connected to the coil.

5. The relay rear end protection circuit according to claim 4, characterized in that: The low-side driving circuit also includes a first current limiting resistor and a second current limiting resistor, wherein the first current limiting resistor is connected in series between the output end of the controller and the base of the transistor, and the second current limiting resistor is connected between the base and the emitter of the transistor.

6. The relay rear end protection circuit according to claim 5, characterized in that: The low-side driving circuit further includes a diode, an anode of the diode is connected to the collector of the transistor, and a cathode of the diode is connected to the coil.

7. The relay rear end protection circuit according to claim 2, characterized in that: When the relay is closed, the first contact is connected to the third contact, and when the relay is opened, the first contact is connected to the second contact.

8. A vehicle-mounted controller, characterized in that: It comprises a relay back-end protection circuit as claimed in any one of claims 1 to 7.

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