Over-current protection control circuit for electromagnetic valve of vehicle-mounted refrigerator

Abstract

The utility model relates to the technical field of integrated circuits, in particular to a vehicle-mounted refrigerator solenoid valve overcurrent protection control circuit, which comprises an overcurrent detection module used for detecting a fault when the overcurrent time of a solenoid valve connected to a driving module reaches a threshold value; the current limiting module is connected with the over-current detection module and is used for limiting current when the over-current detection module detects a fault; the overcurrent fault-tolerant delay protection module is connected behind the current limiting module and is used for filtering short-time large current caused by the electromagnetic valve; and the anomaly detection and control module comprises an MCU chip and is used for detecting the number of anomaly times in the control circuit, limiting the current through MCU chip disability control when the number of anomaly times exceeds a set threshold value and trying to re-drive the electromagnetic valve after a preset interval time. The over-current protection control circuit is designed to meet the requirements of low-cost and high-reliability products, relates to products for protecting current sensitivity in a vehicle-mounted refrigerator, and is high in fault tolerance and good in protection effect.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, in particular to an overcurrent protection control circuit for a solenoid valve of a vehicle refrigerator. Background Art

[0002] In recent years, with the booming development of the car refrigerator market, multi-door car refrigerators have been widely welcomed for their convenience and practicality. Among these products, DC solenoid valves are particularly common, which allow a single compressor to change the flow direction of the refrigerant by controlling the switch of the solenoid valve, thereby achieving refrigeration of multiple boxes. However, as the role of solenoid valves in car refrigerators becomes more and more important, how to ensure their safe and reliable operation in a complex and changing working environment has become an urgent problem to be solved. Utility Model Content

[0003] The utility model aims to provide an overcurrent protection control circuit for a solenoid valve of a vehicle refrigerator, which is designed to meet the demand for low-cost and high-reliability products and relates to a vehicle refrigerator for protecting current-sensitive products. The overcurrent protection control circuit has high fault tolerance and good protection effect.

[0004] To achieve this purpose, the utility model adopts the following technical solutions:

[0005] A vehicle refrigerator solenoid valve overcurrent protection control circuit, comprising:

[0006] An overcurrent detection module is used to detect a fault when the overcurrent time of the solenoid valve connected to the drive module reaches a threshold;

[0007] A current limiting module, connected to the overcurrent detection module, and configured to limit the current when the overcurrent detection module detects a fault;

[0008] An overcurrent fault-tolerant delayed protection module, connected after the current limiting module, is used to filter out the short-term high current caused by the solenoid valve to avoid immediate triggering of false protection;

[0009] An abnormality detection and control module, including an MCU chip, is used to detect the number of abnormalities in the control circuit, and limit the current through the MCU chip disabling control when the number of abnormalities exceeds a set threshold, and try to re-drive the solenoid valve after a preset interval time;

[0010] The driving module is used to drive the solenoid valve of the vehicle refrigerator and is connected to the overcurrent detection module, the current limiting module, the overcurrent fault-tolerant delay protection module and the abnormality detection and control module.

[0011] Preferably, the overcurrent detection module includes a solenoid valve power supply VCC terminal, a sampling resistor RCS1, a transistor Q1, a transistor Q2, a resistor R1 and a resistor R2;

[0012] The solenoid valve power supply VCC end is electrically connected to one end of the sampling resistor RCS1 and the emitter of the transistor Q1, respectively; the other end of the sampling resistor RCS1 is electrically connected to the first input end of the current limiting module and one end of the resistor R1, respectively; the other end of the resistor R1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2, respectively; the other end of the resistor R2 is electrically connected to the collector of the transistor Q2, the collector of the transistor Q1 is electrically connected to the second input end of the current limiting module, the emitter of the transistor Q2 is grounded, and the base of the transistor Q2 is connected to the second port of the abnormality detection and control module.

[0013] Preferably, the current limiting module includes a resistor R3, a resistor R4, a resistor R5 and a transistor Q3;

[0014] One end of the resistor R4 and the emitter of the transistor Q3 are both electrically connected to the other end of the sampling resistor RCS1, one end of the resistor R4 serves as the first input end of the current limiting module, the other end of the resistor R4 and the collector of the transistor Q3 are both electrically connected to the VCC end of the driving module, the base of the transistor Q3 is respectively electrically connected to one end of the resistor R3, one end of the resistor R5 and the input end of the overcurrent fault-tolerant delay protection module, the other end of the resistor R3 serves as the second input end of the current limiting module, the other end of the resistor R3 is electrically connected to the collector of the transistor Q1, and the other end of the resistor R5 is grounded.

[0015] Preferably, the overcurrent fault-tolerant delay protection module includes a capacitor EC1, the positive electrode of the capacitor EC1 serves as the input end of the overcurrent fault-tolerant delay protection module, the positive electrode of the capacitor EC1 is electrically connected to the current limiting module and the abnormality detection and control module respectively, and the negative electrode of the capacitor EC1 is grounded.

[0016] Preferably, the model of the MCU chip is SC95F8616B;

[0017] The first port of the MCU chip is grounded;

[0018] The second port of the MCU chip is the working voltage VDD terminal;

[0019] The third port of the MCU chip is electrically connected to the base of the transistor Q2;

[0020] The fourth port of the MCU chip is electrically connected to the positive electrode of the capacitor EC1.

[0021] Preferably, the transistor Q1 and the transistor Q3 are PNP transistors, and the transistor Q2 is an NPN transistor.

[0022] Preferably, the driving module includes a U1 chip, and the model of the U1 chip is rz7899;

[0023] The GND port of the U1 chip is grounded, and the VCC port of the U1 chip is electrically connected to the output end of the current limiting module.

[0024] One of the above technical solutions has the following beneficial effects: when the load connected to the driving module has a relatively long period of overcurrent, the overcurrent detection module can quickly detect and start the current limiting module to limit the current. At the same time, the overcurrent fault-tolerant delay protection module ensures that the short-term large current caused by the inductive solenoid valve will not be misjudged as a fault, and the abnormality detection and control module can realize the overall stable operation and abnormality handling of the control circuit based on the control of the MCU. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an overcurrent protection control circuit of a solenoid valve of a vehicle refrigerator of the utility model;

[0026] In the accompanying drawings: an overcurrent detection module 1, a driving module 2, a current limiting module 3, an overcurrent fault-tolerant delay protection module 4, and an abnormality detection and control module 5. DETAILED DESCRIPTION

[0027] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, the meaning of "plurality" is two or more.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] like Figure 1 As shown, a vehicle refrigerator solenoid valve overcurrent protection control circuit includes:

[0032] An overcurrent detection module 1 is used to detect a fault when the overcurrent time of the solenoid valve connected to the drive module 2 reaches a threshold;

[0033] A current limiting module 3, connected to the overcurrent detection module 1, and configured to limit the current when the overcurrent detection module 1 detects a fault;

[0034] An overcurrent fault-tolerant delayed protection module 4 is connected after the current limiting module 3 and is used to filter out the short-term high current caused by the solenoid valve to avoid immediately triggering false protection;

[0035] The abnormality detection and control module 5 includes an MCU chip, which is used to detect the number of abnormalities in the control circuit, and limit the current through the MCU chip disabling control when the number of abnormalities exceeds a set threshold, and try to re-drive the solenoid valve after a preset interval time;

[0036] The driving module 2 is used to drive the solenoid valve of the vehicle refrigerator and is connected to the overcurrent detection module 1, the current limiting module 3, the overcurrent fault-tolerant delay protection module 4 and the abnormality detection and control module 5.

[0037] Through the above modules, when the load connected to the driving module 2 has a relatively long overcurrent, the overcurrent detection module 1 can quickly detect and start the current limiting module 3 to limit the current. At the same time, the overcurrent fault-tolerant delay protection module 4 ensures that the short-term large current caused by the inductive solenoid valve will not be misjudged as a fault, and the abnormality detection and control module 5 can realize the overall stable operation and abnormality handling of the control circuit based on the control of the MCU.

[0038] To further illustrate, the overcurrent detection module 1 includes a solenoid valve power supply VCC terminal, a sampling resistor RCS1, a transistor Q1, a transistor Q2, a resistor R1 and a resistor R2;

[0039] The solenoid valve power supply VCC end is electrically connected to one end of the sampling resistor RCS1 and the emitter of the transistor Q1, respectively; the other end of the sampling resistor RCS1 is electrically connected to the first input end of the current limiting module 3 and one end of the resistor R1, respectively; the other end of the resistor R1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2, respectively; the other end of the resistor R2 is electrically connected to the collector of the transistor Q2, the collector of the transistor Q1 is electrically connected to the second input end of the current limiting module 3, the emitter of the transistor Q2 is grounded, and the base of the transistor Q2 is connected to the second port of the abnormality detection and control module 5.

[0040] When an abnormally large current flows through the solenoid valve, a certain voltage drop △V is generated across the sampling resistor RCS1, causing the voltage of the emitter of the transistor Q1 to be greater than the voltage of the base of the transistor Q1. The transistor Q1 is turned on, and the current of the solenoid valve flows to the current limiting module 3 for current limiting.

[0041] To further illustrate, the current limiting module 3 includes a resistor R3, a resistor R4, a resistor R5 and a transistor Q3;

[0042] One end of the resistor R4 and the emitter of the transistor Q3 are both electrically connected to the other end of the sampling resistor RCS1, one end of the resistor R4 serves as the first input end of the current limiting module 3, the other end of the resistor R4 and the collector of the transistor Q3 are both electrically connected to the VCC end of the driving module 2, the base of the transistor Q3 is respectively electrically connected to one end of the resistor R3, one end of the resistor R5 and the input end of the overcurrent fault-tolerant delay protection module 4, the other end of the resistor R3 serves as the second input end of the current limiting module 3, the other end of the resistor R3 is electrically connected to the collector of the transistor Q1, and the other end of the resistor R5 is grounded.

[0043] When the solenoid valve operates normally, the current of the solenoid valve flows through transistor Q3;

[0044] When an abnormally large current appears in the solenoid valve, part of the current of the solenoid valve flows through the current limiting resistor R4 to reduce the current flowing through the solenoid valve coil. At the same time, the transistor Q1 in the overcurrent detection module 1 is turned on, and the other part of the current of the solenoid valve is divided by the resistors R3 and R5.

[0045] To further explain, the overcurrent fault-tolerant delay protection module 4 includes a capacitor EC1, the positive electrode of the capacitor EC1 serves as the input end of the overcurrent fault-tolerant delay protection module 4, the positive electrode of the capacitor EC1 is electrically connected to the current limiting module 3 and the abnormality detection and control module 5 respectively, and the negative electrode of the capacitor EC1 is grounded.

[0046] When an abnormally large current appears in the solenoid valve, the transistor Q1 in the overcurrent detection module 1 is turned on, and the other part of the current of the solenoid valve is divided by resistors R3 and R5, while charging the capacitor EC1. When the voltage of the capacitor EC1 rises to a voltage close to the voltage of the solenoid valve power supply VCC, the base voltage of the transistor Q3 is greater than the emitter voltage of the transistor Q1, and the transistor Q3 is turned off. At this time, the other part of the current of the solenoid valve can only flow through the current limiting resistor R4 to reduce the current.

[0047] Therefore, even if there is a brief overcurrent in the control circuit that turns on transistor Q1, it will take a certain amount of time for capacitor E1 to be fully charged to turn off transistor Q3. During this period, if the current returns to normal and does not reach the voltage difference for Q3 to turn on, transistor Q3 will not turn on immediately, which has the effect of overcurrent fault tolerance delayed protection.

[0048] Further explanation: the model of the MCU chip is SC95F8616B;

[0049] The first port of the MCU chip is grounded;

[0050] The second port of the MCU chip is the working voltage VDD terminal;

[0051] The third port of the MCU chip is electrically connected to the base of the transistor Q2;

[0052] The fourth port of the MCU chip is electrically connected to the positive electrode of the capacitor EC1.

[0053] Specifically, the MCU chip can detect the voltage at the capacitor EC1. When the current of the solenoid valve is normal, the input signal MCU_DET of the fourth port of the MCU chip detects a low level.

[0054] When the current of the solenoid valve is abnormal, the transistor Q1 is turned on and the transistor Q3 is turned off. At this time, the input signal MCU_DET of the fourth port of the MCU chip detects a high level.

[0055] In the current limiting module 3, the transistor Q1 can be reopened after the current is limited by the resistor R4. At this time, the capacitor EC1 is slowly discharged to keep the transistor Q3 off. The positive electrode of the capacitor EC1, i.e., MCU_DET, will not be pulled down immediately. The MCU chip detects an intermittent overcurrent mark, and then determines that the solenoid valve is abnormal. The voltage at the base of the transistor Q2, i.e., MCU_EN, is pulled up to turn on the transistor Q2 to maintain the current limiting. At the same time, after the capacitor EC1 is discharged, the transistor Q3 can be turned on again to release the current limit again and try to drive the solenoid valve.

[0056] Furthermore, by recording the number of times the MCU_DET high level signal is detected at the 4th port input signal MCU_DET of the MCU chip, current abnormality is detected. When a certain number of times is reached, the level of the MCU_EN output signal at the 3rd port of the MCU chip is raised to make the transistor Q2 conductive to the ground. At this time, the transistor Q1 is normally open to charge the capacitor EC1 and turn off the transistor Q3 to lock the drive circuit. After a certain delay, the level of the MCU_EN output signal at the 4th port of the MCU chip is lowered again to try to restart. If overcurrent occurs after a certain number of times, the MCU chip determines that the load is abnormal, and notifies or displays it to the user in an unlimited manner so that the user can know how to deal with it.

[0057] To further explain, the transistor Q1 and the transistor Q3 are PNP transistors, and the transistor Q2 is an NPN transistor.

[0058] Further explanation, the driving module 2 includes a U1 chip, and the model of the U1 chip is rz7899;

[0059] The GND port of the U1 chip is grounded, and the VCC port of the U1 chip is electrically connected to the output end of the current limiting module 3 .

[0060] The U1 chip is used to control the direction of the solenoid valve.

[0061] The technical principle of the present invention is described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations here, technicians in this field can think of other specific implementations of the present invention without creative work, and these equivalent variations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A vehicle refrigerator solenoid valve overcurrent protection control circuit, characterized in that: include: An overcurrent detection module (1) is used to detect a fault when the overcurrent time of the solenoid valve connected to the drive module (2) reaches a threshold value; A current limiting module (3), connected to the overcurrent detection module (1), and used to limit current when the overcurrent detection module (1) detects a fault; An overcurrent fault-tolerant delayed protection module (4), connected after the current limiting module (3), is used to filter out the short-term high current caused by the solenoid valve to avoid immediate triggering of false protection; An abnormality detection and control module (5), including an MCU chip, is used to detect the number of abnormalities in the control circuit, and when the number of abnormalities exceeds a set threshold, the MCU chip is disabled to limit the current, and an attempt is made to re-drive the solenoid valve after a preset interval time; The driving module (2) is used to drive the solenoid valve of the vehicle refrigerator and is connected to the overcurrent detection module (1), the current limiting module (3), the overcurrent fault-tolerant delay protection module (4) and the abnormality detection and control module (5).

2. The vehicle refrigerator solenoid valve overcurrent protection control circuit according to claim 1, characterized in that: The overcurrent detection module (1) comprises a solenoid valve power supply VCC terminal, a sampling resistor RCS1, a transistor Q1, a transistor Q2, a resistor R1 and a resistor R2; The solenoid valve power supply VCC end is electrically connected to one end of the sampling resistor RCS1 and the emitter of the transistor Q1 respectively; the other end of the sampling resistor RCS1 is electrically connected to the first input end of the current limiting module (3) and one end of the resistor R1 respectively; the other end of the resistor R1 is electrically connected to the base of the transistor Q1 and one end of the resistor R2 respectively; the other end of the resistor R2 is electrically connected to the collector of the transistor Q2; the collector of the transistor Q1 is electrically connected to the second input end of the current limiting module (3); the emitter of the transistor Q2 is grounded; and the base of the transistor Q2 is connected to the second port of the abnormality detection and control module (5).

3. The vehicle refrigerator solenoid valve overcurrent protection control circuit according to claim 2, characterized in that: The current limiting module (3) comprises a resistor R3, a resistor R4, a resistor R5 and a transistor Q3; One end of the resistor R4 and the emitter of the transistor Q3 are both electrically connected to the other end of the sampling resistor RCS1; one end of the resistor R4 serves as the first input end of the current limiting module (3); the other end of the resistor R4 and the collector of the transistor Q3 are both electrically connected to the VCC end of the driving module (2); the base of the transistor Q3 is respectively electrically connected to one end of the resistor R3, one end of the resistor R5 and the input end of the overcurrent fault tolerance delay protection module (4); the other end of the resistor R3 serves as the second input end of the current limiting module (3); the other end of the resistor R3 is electrically connected to the collector of the transistor Q1; and the other end of the resistor R5 is grounded.

4. The vehicle refrigerator solenoid valve overcurrent protection control circuit according to claim 3, characterized in that: The overcurrent fault-tolerant delay protection module (4) comprises a capacitor EC1, the positive electrode of the capacitor EC1 serves as the input end of the overcurrent fault-tolerant delay protection module (4), the positive electrode of the capacitor EC1 is electrically connected to the current limiting module (3) and the abnormality detection and control module (5), respectively, and the negative electrode of the capacitor EC1 is grounded.

5. The vehicle refrigerator solenoid valve overcurrent protection control circuit according to claim 4, characterized in that: The model of the MCU chip is SC95F8616B; The first port of the MCU chip is grounded; The second port of the MCU chip is the working voltage VDD terminal; The third port of the MCU chip is electrically connected to the base of the transistor Q2; The fourth port of the MCU chip is electrically connected to the positive electrode of the capacitor EC1.

6. The vehicle refrigerator solenoid valve overcurrent protection control circuit according to claim 5, characterized in that: The transistor Q1 and the transistor Q3 are PNP transistors, and the transistor Q2 is an NPN transistor.

7. The vehicle refrigerator solenoid valve overcurrent protection control circuit according to claim 1, characterized in that: The driving module (2) comprises a U1 chip, the model of the U1 chip is rz7899; The GND port of the U1 chip is grounded, and the VCC port of the U1 chip is electrically connected to the output end of the current limiting module (3).

Images