Protection circuit of vehicle-mounted inverter
By integrating a switching module and protection circuit into the vehicle inverter, the power input voltage is detected and the conduction speed is controlled, which solves the problems caused by blown fuses and hot-plugging, and realizes overvoltage, undervoltage and hot-plugging protection of the circuit to ensure circuit safety.
Patent Information
- Application Number
- CN202423248366.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-12-16
- Estimated Expiration
- 2034-12-25
AI Technical Summary
Existing vehicle inverters are prone to fuse burnout when compatible with 12V and 24V inputs, and user hot-plugging can cause large current surges in the wiring, which can easily lead to malfunctions.
Design a vehicle inverter protection circuit, including a switching module, a first protection circuit, and a second protection circuit. By detecting the power input voltage and controlling the conduction and conduction speed of the switching module, overvoltage, undervoltage, and hot-swap protection are achieved to avoid instantaneous large current.
It effectively protects the vehicle inverter, preventing problems such as blown fuses and electrical sparks caused by hot-plugging, and ensuring safe and stable circuit operation.
Smart Images
Figure CN223680740U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of protection circuit, in particular to a protection circuit of vehicle-mounted inverter. BACKGROUND
[0002] The automobile lighter port is usually provided with 12V and 24V outputs, and the vehicle-mounted inverter is designed to be compatible with only 12V input or 24V input for efficiency and cost reduction. Meanwhile, the fuse of the vehicle-mounted inverter is usually small, which is prone to cause the problem of fuse burnout. In addition, some users use external battery clamps as the power input of the vehicle-mounted inverter, and the battery voltage is usually set to multiple values, such as 48V. In addition, when the user clamps the battery or uses the automobile lighter port, the vehicle-mounted inverter is usually connected in a hot plug manner, which causes the vehicle-mounted inverter to be prone to overcurrent impact and failure. CONTENT OF THE UTILITY MODEL
[0003] The present application aims to at least solve one of the technical problems in the prior art, and provides a protection circuit of vehicle-mounted inverter, which can integrate multiple circuit protection functions in the vehicle-mounted inverter.
[0004] The present application provides a protection circuit of vehicle-mounted inverter, which comprises a switching module, a first protection circuit and a second protection circuit.
[0005] The switching module is connected between the power input end of the protection circuit and the power output end of the protection circuit, and is used to control the on-off of the protection circuit.
[0006] The input end of the first protection circuit is connected to the power input end, which is used to detect the input voltage of the power input end and output a control signal for controlling the switching module to be turned on when the input voltage meets the preset range.
[0007] The output end of the first protection circuit is connected to the input end of the second protection circuit, and the second protection circuit is connected to the switching module. The second protection circuit is used to receive the control signal to control the switching module to be turned on, and control the turn-on speed of the switching module.
[0008] According to the technical scheme of the embodiment of the present application, at least the following beneficial effects are achieved: the switch module is connected between the power input end of the protection circuit and the power output end of the protection circuit, and is turned on when the voltage input at the power input end is safe; the first protection circuit is configured to detect the input voltage at the power input end, and output a control signal for controlling the switch module to be turned on when the input voltage is within a preset range; because the first protection circuit and the switch module are both connected to the power input end, when the control signal controls the switch module to be turned on, the power input end and the power output end are connected, so that the voltage of the circuit is limited and protected by the preset range of the first protection circuit; when the preset range includes an upper limit value and a lower limit value, the upper limit protection and the lower limit protection can be realized at the same time; the second protection circuit is configured to receive the control signal to control the switch module to be turned on, and control the turn-on speed of the switch module, for example, control the turn-on speed of the switch module to be slow, so that the instantaneous large current caused by the instantaneous turn-on when the power input end is powered can be avoided, and problems such as electric spark caused by the hot plug process can be avoided; therefore, by the first protection circuit and the second protection circuit, the overvoltage protection, the undervoltage protection and the hot plug protection of the circuit can be realized, and the damage of the equipment caused by different voltage inputs of the user can be avoided.
[0009] According to some embodiments of the present application, the first protection circuit includes a first voltage division module and a first driver, the first voltage division module includes a first voltage division node, an input end of the first driver is connected to the first voltage division node, and an output end of the first driver is connected to an input end of the second protection circuit; the first driver is configured to be turned on when the voltage at the first voltage division node is greater than a reference voltage of the first driver.
[0010] According to some embodiments of the present application, the first protection circuit further includes a second voltage division module and a second driver, the second voltage division module includes a second voltage division node, an input end of the second driver is connected to the second voltage division node, and an output end of the second driver is connected to the first voltage division node; the second driver is configured to be turned on when the voltage at the second voltage division node is greater than a reference voltage of the second driver; one end of the first voltage division module and one end of the second voltage division module are both connected to the power input end.
[0011] According to some embodiments of the present application, the first protection circuit further includes a voltage limit adjustment module, the voltage limit adjustment module is connected between the first voltage division node and the output end of the second driver, and the voltage limit adjustment module is configured to adjust the preset range.
[0012] According to some embodiments of the present application, the first voltage dividing module comprises a third resistor and a fourth resistor, the second voltage dividing module comprises a first resistor and a second resistor, the first voltage dividing node is located between the third resistor and the fourth resistor, the second voltage dividing node is located between the first resistor and the second resistor, and the voltage limiting adjustment module comprises a seventh resistor, and the preset range is adjusted by changing the resistance value of the seventh resistor.
[0013] According to some embodiments of the present application, the second protection circuit comprises a first delay module and a switch connection node, the first delay module comprises a first capacitor and a fifth resistor, and one end of the first capacitor and the fifth resistor is connected to the switch module, and the other end is connected to the switch connection node.
[0014] According to some embodiments of the present application, the second protection circuit further comprises a second delay module, the second delay module comprises a sixth resistor, and the sixth resistor is connected between the switch connection node and the output end of the first protection circuit.
[0015] According to some embodiments of the present application, the switch module comprises a first switch tube and a second switch tube, the first switch tube and the second switch tube each comprise a control pin, and the control pin of the first switch tube and the control pin of the second switch tube are connected to the switch connection node.
[0016] According to some embodiments of the present application, the first switch tube and the second switch tube each further comprise two switch pins, one switch pin of the first switch tube is connected to the power input end, one switch pin of the second switch tube is connected to the power output end, the other switch pin of the first switch tube and the second switch tube is connected, and the conduction direction of the first switch tube and the second switch tube is opposite.
[0017] According to some embodiments of the present application, the first switch tube and the second switch tube are MOSFETs.
[0018] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and achieved by means of the structures particularly pointed out in the description and claims. BRIEF DESCRIPTION OF DRAWINGS
[0019] The accompanying drawings are included to provide a further understanding of the technical scheme of the present application, and constitute a part of the specification, and are used to explain the technical scheme of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical scheme of the present application.
[0020] The present application will be further described below in conjunction with the drawings and embodiments.
[0021] Figure 1 is a structural schematic block diagram of a protection circuit provided by an embodiment of the present application;
[0022] Figure 2 is a circuit structure diagram of a protection circuit provided by another embodiment of the present application.
[0023] Legend: 100, switch module; 200, first protection circuit; 300, second protection circuit; 210, first voltage division module; 220, second voltage division module; 310, first delay module; 320, second delay module. DETAILED DESCRIPTION
[0024] This part will describe the specific embodiments of the present application in detail, the preferred embodiments of the present application are shown in the drawings, the role of the drawings is to supplement the description of the text part with graphics, so that people can intuitively and visually understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the protection scope of the present application.
[0025] In the description of the present application, it is understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.
[0026] In the description of the present application, the meaning of several is one or more, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features
[0027] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.
[0028] The following will be described in conjunction with the accompanying Figures 1-2 , the present application will be further described.
[0029] As Figure 1 shown, Figure 1A structure schematic block diagram of a protection circuit of a vehicle-mounted inverter is provided in an embodiment of the present application, and the protection circuit of the vehicle-mounted inverter comprises: a switch module 100, a first protection circuit 200 and a second protection circuit 300.
[0030] The switch module 100 is connected between a power input end VIN of the protection circuit and a power output end VOUT of the protection circuit, and is used for controlling on-off of the protection circuit.
[0031] The input end of the first protection circuit 200 is connected to the power input end VIN, and is used for detecting an input voltage of the power input end VIN and outputting a control signal for controlling the switch module 100 to be turned on when the input voltage meets a preset range.
[0032] The output end of the first protection circuit 200 is connected to the input end of the second protection circuit 300, and the second protection circuit 300 is connected to the switch module 100, and the second protection circuit 300 is used for receiving the control signal to control the switch module 100 to be turned on and control a turn-on speed of the switch module 100.
[0033] In the embodiment, the switch module 100 is connected between the power input end VIN of the protection circuit and the power output end VOUT of the protection circuit, and is used for controlling on-off of the protection circuit, that is, the switch module 100 is turned on when the input voltage of the power input end VIN meets a preset condition, and the current is allowed to pass through, and the switch module 100 is turned off when the voltage is abnormal, so as to protect the protection circuit from being damaged; the switch module 100 can be an electronic switch, that is, a switch for realizing on-off of the circuit by using electronic elements, for example, a transistor switch, a MOSFET switch and the like.
[0034] In an embodiment, the switch module 100 can also adopt a switch element such as a relay, and the type of the switch adopted by the switch module 100 can be selected according to parameters such as current, voltage and power of a load, stability of the switch module 100 in an environment such as temperature, humidity and vibration and the like.
[0035] The input end of the first protection circuit 200 is directly connected to the power input end VIN, and the output end is connected to the second protection circuit 300, and the first protection circuit 200 is used for monitoring voltage of the power input end VIN in real time, and outputs a control signal for controlling the switch module 100 to be turned on when it is detected that the input voltage meets a preset range, and the control signal can be a pulse signal, a level signal or other forms, which depends on the type and requirement of the switch module 100.
[0036] In an embodiment, the first protection circuit 200 can implement overvoltage protection, for example, when the input voltage exceeds the maximum value of the preset range, the first protection circuit 200 outputs a low-level signal to make the switch module 100 disconnected, thereby avoiding damage to the circuit by overvoltage; the first protection circuit 200 can also implement under-voltage protection, for example, when the input voltage is lower than the minimum value of the preset range, the first protection circuit 200 also outputs a low-level signal, and the switch module 100 is disconnected to prevent the impact of under-voltage on the circuit; voltage fluctuation detection: the first protection circuit 200 can also implement voltage fluctuation monitoring, when the voltage fluctuation is large, the first protection circuit 200 also outputs a low-level signal, and the switch module 100 is disconnected to protect the circuit.
[0037] In an embodiment, the first protection circuit 200 can be a built-in voltage detection module, which accurately detects the input voltage, so that when the input voltage is within the preset range, the voltage detection module outputs a high-level signal, that is, a control signal for controlling the switch module 100 to be turned on; when the input voltage exceeds the preset range, a low-level signal is output.
[0038] In an embodiment, the input end of the second protection circuit 300 is connected to the output end of the first protection circuit 200, and the output end is connected to the switch module 100. After receiving the control signal of the first protection circuit 200, the second protection circuit 300 can control the conduction speed of the switch module 100 according to the signal type and intensity.
[0039] In an embodiment, the second protection circuit 300 can implement hot plug protection and overcurrent protection, for example, at the moment of hot plug connection of the power supply, the second protection circuit 300 can control the switch module 100 to slowly conduct, reduce the starting current, and prevent the impact on the circuit; the second protection circuit 300 can also implement overcurrent protection, for example, when the current in the circuit exceeds the set value, the second protection circuit 300 adjusts the conduction speed of the switch module 100 to make it disconnected, thereby implementing overcurrent protection.
[0040] In an embodiment, the second protection circuit 300 can have a built-in conduction speed control module for adjusting the conduction speed of the switch module 100. By controlling the conduction speed, hot plug protection, overcurrent protection and other functions of the circuit can be achieved.
[0041] It can be understood that the input end of the first protection circuit 200 is connected to the power input end VIN, the output end of the first protection circuit 200 is connected to the input end of the second protection circuit 300, and the second protection circuit 300 is connected to the switch module 100. In this way, the protection circuit can include a first circuit from the power input end VIN-the first protection circuit 200-the second protection circuit 300-the switch module 100-the power output end VOUT, and since the switch module 100 is also connected to the power input end VIN, that is, the input end of the first protection circuit 200 and the switch module 100 are both connected to the power input end VIN, the protection circuit can also include a second circuit from the power input end VIN-the switch module 100-the power output end VOUT, the input end and the output end of the first circuit and the second circuit are the same, and the first circuit and the second circuit are equivalent to being connected in parallel.
[0042] Based on this, after the input voltage from the outside is input from the power input end VIN, it will be input to the first circuit and the second circuit at the same time. Since the switch module 100 needs the control signal output by the first protection circuit 200 to control to be turned on, in the second circuit, the switch module 100 is initially in an off state, and the second circuit is initially in a non-conducting state, so the input voltage cannot be directly output from the second circuit; in the first circuit, the switch module 100 is also initially in an off state, and the first circuit is also initially in a non-conducting state, but after the input voltage passes through the first protection circuit 200, the first protection circuit 200 can detect the input voltage of the power input end VIN, for example, detect the size and frequency of the input voltage, etc. When the input voltage meets the preset range, the first protection circuit 200 will output a control signal for controlling the switch module 100 to be turned on.
[0043] The control signal is transmitted to the second protection circuit 300 through the connection between the output end of the first protection circuit 200 and the input end of the second protection circuit 300, and the control signal is transmitted to the switch module 100 after passing through the second protection circuit 300 to make the switch module 100 conductive. However, the second protection circuit 300 can control the conduction speed of the switch module 100, so when the control signal passes through the second protection circuit 300, the second protection circuit 300 can reduce the conduction speed of the switch module 100 to make the switch module 100 conduct slowly. The way the second protection circuit 300 can reduce the conduction speed of the switch module 100 can be to reduce the speed of the control signal passing through the second protection circuit 300.
[0044] Based on this, when the input voltage passes through the first protection circuit 200, if the input voltage is not in the preset range, for example, the input voltage is too large or too small, the first protection circuit 200 will not output the control signal for controlling the switch module 100 to be turned on, so that neither the first circuit nor the second circuit is turned on, which is equivalent to limiting the input voltage in the safe range through the first protection circuit 200, realizing overvoltage protection and undervoltage protection of the circuit; in addition, the second protection circuit 300 reduces the turn-on speed of the switch module 100, which can avoid the instantaneous large current when the power supply input end VIN is powered, thereby avoiding the problem of electric spark in the hot plug process.
[0045] In the protection circuit provided in some embodiments of the present application, as shown in Figure 2 The first protection circuit 200 includes a first voltage division module 210 and a first driver D2, the first voltage division module 210 includes a first voltage division node B, and the input end of the first driver D2 is connected to the first voltage division node B. The output end of the first driver D2 is connected to the input end of the second protection circuit 300, and the first driver D2 is used to be turned on when the voltage at the first voltage division node B is greater than the reference voltage of the first driver D2.
[0046] In the present embodiment, the first protection circuit 200 includes a first voltage division module 210 and a first driver D2. It can be understood that the first voltage division module 210 is used to monitor the input voltage of the power supply input end VIN, and the first voltage division module 210 can be composed of a plurality of resistors connected in series or parallel according to a specific ratio to form a voltage division network. In the voltage division network, the first voltage division node B is located at one of the nodes between the plurality of connection nodes of the plurality of resistors. When the voltage of the power supply input end VIN is applied to the voltage division network, the voltage at the first voltage division node B will be a proportional value of the input voltage, and the voltage division ratio is determined by the voltage division ratio of the resistors; the voltage at the first voltage division node B is the voltage output to the first driver D2. Therefore, when setting the resistors of the first voltage division module 210 and selecting the first voltage division node B, the voltage safety range required can be referred to, to ensure that the voltage at the first voltage division node B meets the requirements of the voltage safety range when the input voltage is normal; it can be understood that the main function of the first voltage division module 210 is to reduce the input voltage to a safe level, so that the first driver D2 can perform reliable voltage comparison and driving operation within its working voltage range.
[0047] The first driver D2 receives the voltage signal of the first voltage divider node B and compares it with the built-in reference voltage. When the voltage of the first voltage divider node B is greater than the reference voltage of the first driver D2, it is turned on so that the voltage signal of the first voltage divider node B can be transmitted through the first driver D2, thereby controlling the switch module 100 to turn on. Therefore, when the first driver D2 is turned on, the voltage signal of the first voltage divider node B can be output through the first driver D2, that is, the voltage signal of the first voltage divider node B can be used as a control signal for controlling the switch module 100 to turn on.
[0048] Based on this, when the voltage at the power input terminal VIN is normal, the first voltage divider module 210 reduces the input voltage proportionally and forms a stable voltage signal at the first voltage divider node B. The first driver D2 receives the voltage signal at the first voltage divider node B. Since the voltage at the first voltage divider node B exceeds the reference voltage, the first driver D2 is turned on and sends a control signal to the second protection circuit 300 through the output terminal of the first driver D2, so that the switch module 100 is turned on.
[0049] When the voltage at the power input terminal VIN drops abnormally, the voltage at the first voltage divider node B will also drop accordingly. The first driver D2 receives the voltage signal from the first voltage divider node B. Since the voltage at the first voltage divider node B does not exceed the reference voltage, the first driver D2 does not conduct and will not output a control signal.
[0050] In some embodiments of the protection circuit provided in this application, such as Figure 2 As shown, Figure 2 This is a circuit diagram of a protection circuit provided in another embodiment of this application. The first protection circuit 200 further includes a second voltage divider module 220 and a second driver D1. The second voltage divider module 220 includes a second voltage divider node A. The input terminal of the second driver D1 is connected to the second voltage divider node A, and the output terminal of the second driver D1 is connected to the first voltage divider node B. The second driver D1 is used to conduct when the voltage of the second voltage divider node A is greater than the reference voltage of the second driver D1. One end of the first voltage divider module 210 and the second voltage divider module 220 are both connected to the power input terminal VIN.
[0051] In this embodiment, one end of the first voltage divider module 210 and the second voltage divider module 220 are both connected to the power input terminal VIN, and the other end is both grounded, that is, the first voltage divider module 210 and the second voltage divider module 220 are connected in parallel.
[0052] The first protection circuit 200 comprises a second voltage dividing module 220 and a second driver D1. It can be understood that the second voltage dividing module 220 is used to monitor the input voltage of the power input terminal VIN, and the second voltage dividing module 220 can be composed of a plurality of resistors connected in series or parallel according to a specific ratio to form a voltage dividing network. In the voltage dividing network, the second voltage dividing node A is located at one of the connection nodes between the plurality of resistors. When the voltage of the power input terminal VIN is applied to the voltage dividing network, the voltage at the second voltage dividing node A will be a proportional value of the input voltage, and the voltage dividing ratio is determined by the voltage dividing ratio of the resistors. The voltage at the second voltage dividing node A is the voltage output to the second driver D1, and the voltage signal output by the second driver D1 acts on the first voltage dividing node B of the first voltage dividing module 210. Therefore, when setting the resistors of the second voltage dividing module 220 and selecting the second voltage dividing node A, the required voltage safety range and the voltage requirement of the first voltage dividing node B of the first voltage dividing module 210 can be referred to, to ensure that the voltage of the first voltage dividing node B meets the voltage safety range requirement when the input voltage is normal. It can be understood that the main function of the second voltage dividing module 220 is to reduce the input voltage to a safe level, so that the second driver D1 can perform reliable voltage comparison and driving operation within its working voltage range.
[0053] The second driver D1 is used to receive the voltage signal of the second voltage dividing node A and compare it with the built-in reference voltage. When the voltage of the second voltage dividing node A is greater than the reference voltage of the second driver D1, it is turned on. The voltage signal of the second voltage dividing node A will be transmitted to the first voltage dividing node B through the second driver D1, so that the voltage of the first voltage dividing node B will be changed, which may make the voltage of the first voltage dividing node B less than the reference voltage of the first driver D2, and the first driver D2 will not output the control signal and the switch module 100 will not be turned on. Therefore, the voltage of the second voltage dividing node A needs to be less than the reference voltage of the second driver D1, so that the second driver D1 is not turned on and the first voltage dividing node B is not affected. Therefore, it can be understood that the switch module 100 will be turned on only when the voltage of the second voltage dividing node A is less than the reference voltage of the second driver D1 and the voltage of the first voltage dividing node B is greater than the reference voltage of the first driver D2. The first voltage dividing module 210 and the first driver D2 determine the upper limit of the preset range, and the second voltage dividing module 220 and the second driver D1 determine the lower limit of the preset range. By combining the first voltage dividing module 210 and the first driver D2, and the second voltage dividing module 220 and the second driver D1, overvoltage protection and undervoltage protection of the circuit are realized.
[0054] Based on this, in the case that the voltage of the power input end VIN is normal, the second voltage dividing module 220 proportionally reduces the input voltage and forms a stable voltage signal at the second voltage dividing node A, the second driver D1 receives the voltage signal of the second voltage dividing node A, and since the voltage of the second voltage dividing node A does not exceed the reference voltage, the second driver D1 is not turned on. At the same time, the first voltage dividing module 210 proportionally reduces the input voltage and forms a stable voltage signal at the first voltage dividing node B, the first driver D2 receives the voltage signal of the first voltage dividing node B, and since the voltage of the first voltage dividing node B exceeds the reference voltage, the first driver D2 is turned on, and a control signal is sent to the second protection circuit 300 through the output end of the first driver D2, so that the switch module 100 is turned on.
[0055] In the case that the voltage of the power input end VIN abnormally rises, the voltage at the second voltage dividing node A also rises accordingly, the second driver D1 receives the voltage signal of the second voltage dividing node A, and since the voltage of the second voltage dividing node A exceeds the reference voltage, the second driver D1 is turned on. The first voltage dividing node B is affected by the output end of the second driver D1, which may cause the voltage of the first voltage dividing node B to decrease, and then the first driver D2 does not send a control signal, and the switch module 100 is not turned on.
[0056] It can be understood that the first driver D2 and the second driver D1 are drivers that are compared with the input voltage through a voltage reference and are changed according to the comparison result, and the first driver D2 and the second driver D1 can preferably adopt TL431, which is a kind of adjustable precision shunt regulator. The adjustable external input parameter voltage can change the internal comparison voltage, so as to adjust the output stable voltage.
[0057] In the protection circuit provided in some embodiments of the present application, as shown in Figure 2 The first protection circuit 200 further includes a voltage limiting adjustment module connected between the first voltage dividing node B and the output end of the second driver D1, and the voltage limiting adjustment module is used to adjust the preset range.
[0058] In the embodiment, the voltage limiting adjustment module is connected between the first voltage division node B and the output terminal of the second driver D1, that is, when the second driver D1 is turned on, the voltage limiting adjustment module and the resistor in the first voltage division module 210 are connected in parallel, and the voltage limiting adjustment module can be a circuit module with internal resistance, for example, the voltage limiting adjustment module can include several resistors, or can be a variable resistor, etc., that is, the voltage limiting adjustment module can make the equivalent resistance of the voltage limiting adjustment module and the resistor in the first voltage division module 210 smaller than the initial resistance value of the resistor in the first voltage division module 210 by being connected in parallel with the resistor in the first voltage division module 210, so as to make the voltage value at the first voltage division node B smaller, and the first driver D2 not turned on.
[0059] Therefore, in order to make the first driver D2 turned on, the input voltage needs to be increased, and the input voltage needs to be increased by different values when the internal resistance of the voltage limiting adjustment module is different; in this way, the voltage limiting adjustment module adjusts the limiting range of the input voltage, that is, adjusts the preset range.
[0060] In the protection circuit provided in some embodiments of the application, as shown in Figure 2 the first voltage division module 210 includes a third resistor R3 and a fourth resistor R4, the second voltage division module 220 includes a first resistor R1 and a second resistor R2, the first voltage division node B is located between the third resistor R3 and the fourth resistor R4, the second voltage division node A is located between the first resistor R1 and the second resistor R2, and the voltage limiting adjustment module includes a seventh resistor R7, and the preset range is adjusted by changing the resistance value of the seventh resistor R7.
[0061] In the embodiment, the first voltage division module 210 includes a third resistor R3 and a fourth resistor R4, the second voltage division module 220 includes a first resistor R1 and a second resistor R2, the first voltage division node B is located between the third resistor R3 and the fourth resistor R4, the second voltage division node A is located between the first resistor R1 and the second resistor R2, and in addition, the first driver D2 and the second driver D1 are preferably TL431, and the reference voltage of TL431 is 2.5V; therefore, in order to make the first driver D2 turned on, it can be judged that the input voltage needs to be greater than 2.5V / the fourth resistor R4 value*(the third resistor R3 value+the fourth resistor R4 value);
[0062] In addition, in the embodiment, the seventh resistor R7 is connected between the first voltage division node B and the output terminal of the second driver D1, that is, when the second driver D1 is turned on, the seventh resistor R7 and the resistor in the first voltage division module 210 are connected in parallel, so as to make the voltage value at the first voltage division node B smaller, and the first driver D2 not turned on.
[0063] Therefore, to make the first driver D2 conductive, the input voltage needs to be increased, and when the seventh resistor R7 is a resistor with a different value, the input voltage needs to be increased by a different value; in this way, the seventh resistor R7 adjusts the range of the input voltage, that is, adjusts the preset range;
[0064] Therefore, when the resistance value of the seventh resistor R7 is equal to 0, the input voltage needs to be less than 2.5V / second resistor R2 value*(first resistor R1 value+second resistor R2 value), that is, the preset range is that the input voltage is greater than 2.5V / fourth resistor R4 value*(third resistor R3 value+fourth resistor R4 value) and less than 2.5V / second resistor R2 value*(first resistor R1 value+second resistor R2 value);
[0065] When the resistance value of the seventh resistor R7 is not 0, the preset range is that the input voltage is greater than 2.5V / fourth resistor R4 value*(third resistor R3 value+equivalent resistance value of the fourth resistor R4 and the seventh resistor R7) and less than 2.5V / second resistor R2 value*(first resistor R1 value+second resistor R2 value).
[0066] In the protection circuit provided in some embodiments of the present application, as shown in Figure 2 The second protection circuit 300 includes a first delay module 310 and a switch connection node C, and the first delay module 310 includes a first capacitor C1 and a fifth resistor R5. One end of the first capacitor C1 and the fifth resistor R5 is connected to the switch module 100, and the other end is connected to the switch connection node C.
[0067] In this embodiment, the second protection circuit 300 includes a first delay module 310 and a switch connection node C, and the first delay module 310 includes a first capacitor C1 and a fifth resistor R5. It can be understood that when the switch module 100 acts or the circuit state changes, the first capacitor C1 starts to charge through the fifth resistor R5. The voltage across the capacitor will not change instantaneously, but will gradually increase over time until it reaches or approaches the voltage level of the switch module 100. The charging rate is mainly determined by the value of the first capacitor C1.
[0068] It can be understood that both the charging and discharging processes of the first capacitor C1 involve a time constant, which determines the time required for the capacitor voltage to reach a certain threshold, thereby introducing a delay in the circuit. The delay time usually refers to the time required for the capacitor voltage to change from the initial value to the final value, that is, one time constant. Therefore, in the second protection circuit 300, when a transient disturbance occurs in the circuit, the switch module 100 will not respond immediately, thereby avoiding false operation. For example, if a short voltage spike occurs in the circuit, the delay module can prevent the switch module 100 from triggering immediately. Only when the spike lasts for a certain period of time (more than the delay time), the switch module 100 will act;
[0069] When the input voltage is connected, the input voltage meets the preset range of the first protection circuit 200, and an output control signal is output. The control signal enters the second protection circuit 300 to charge the first capacitor C1. Only when the voltage across the first capacitor C1 reaches the on-voltage of the switch module 100, the switch module 100 is turned on. Therefore, the charging speed of the first capacitor C1 can be adjusted by adjusting the value of the first capacitor C1, and the switching speed of the switch module 100 is adjusted, thereby avoiding the problem of electric spark in the hot plug process. Adjusting the value of the first capacitor C1 will make the switch module 100 slowly turn on, which can also avoid the problem of instantaneous large current when the power output terminal VOUT is powered.
[0070] In the protection circuit provided in some embodiments of the present application, as shown in Figure 2 The second protection circuit 300 further includes a second delay module 320. The second delay module 320 includes a sixth resistor R6, and the sixth resistor R6 is connected between the switch connection node C and the output terminal of the first protection circuit 200.
[0071] In the present embodiment, the second protection circuit 300 further includes a second delay module 320. The second delay module 320 includes a sixth resistor R6, and the sixth resistor R6 is connected between the switch connection node C and the output terminal of the first protection circuit 200. When the input voltage is connected, the input voltage meets the preset range of the first protection circuit 200, and an output control signal is output. The control signal enters the second protection circuit 300 to charge the first capacitor C1. Only when the voltage across the first capacitor C1 reaches the on-voltage of the switch module 100, the switch module 100 is turned on. Therefore, the charging speed of the first capacitor C1 can be adjusted by adjusting the value of the sixth resistor R6 and the first capacitor C1, and the switching speed of the switch module 100 is adjusted, thereby avoiding the problem of electric spark in the hot plug process. Adjusting the value of the sixth resistor R6 and the first capacitor C1 will make the switch module 100 slowly turn on, which can also avoid the problem of instantaneous large current when the power output terminal VOUT is powered.
[0072] In the protection circuit provided in some embodiments of the present application, as shown in Figure 2 The switch module 100 includes a first switch tube Q1 and a second switch tube Q2. The first switch tube Q1 and the second switch tube Q2 each include a control pin. The control pin of the first switch tube Q1 and the control pin of the second switch tube Q2 are both connected to the switch connection node C.
[0073] In the embodiment, the switch module 100 includes a first switch tube Q1 and a second switch tube Q2, and the first switch tube Q1 and the second switch tube Q2 are both switch tubes including control pins, and thus the first switch tube Q1 and the second switch tube Q2 can be IGBT or MOS tube, etc. The control pin of the first switch tube Q1 and the control pin of the second switch tube Q2 are both connected to the switch connection node C. When the input voltage is connected, the switch module 100 is not turned on. When the input voltage meets the preset range of the first protection circuit 200, the control signal is outputted, the voltage of the switch connection node C is pulled down through the control signal, the voltage of the control pin of the first switch tube Q1 and the second switch tube Q2 is pulled down, and thus the switch module 100 is turned on. When the input voltage does not meet the preset range of the first protection circuit 200, the control signal is not outputted, the switch connection node C is high, and thus the switch module 100 is not turned on. Therefore, the first switch tube Q1 and the second switch tube Q2 can be considered as PNP type switch tubes.
[0074] In the protection circuit provided in some embodiments of the present application, as shown in Figure 2 the first switch tube Q1 and the second switch tube Q2 both further include two switch pins. One switch pin of the first switch tube Q1 is connected to the power input end VIN, one switch pin of the second switch tube Q2 is connected to the power output end VOUT, and the other switch pin of the first switch tube Q1 and the second switch tube Q2 is connected. The conduction direction of the first switch tube Q1 and the second switch tube Q2 is opposite.
[0075] In the embodiment, one switch pin of the first switch tube Q1 is connected to the power input end VIN, one switch pin of the second switch tube Q2 is connected to the power output end VOUT, and the other switch pin of the first switch tube Q1 and the second switch tube Q2 is connected. The conduction direction of the first switch tube Q1 and the second switch tube Q2 is opposite. Therefore, when the power is reversely connected, the control signal of the first switch tube Q1 and the second switch tube Q2 has no current loop, and the first switch tube Q1 and the second switch tube Q2 are cut off. Therefore, the safety of the subsequent circuit can be ensured when the power is reversely connected.
[0076] In the protection circuit provided in some embodiments of the present application, as shown in Figure 2 the first switch tube Q1 and the second switch tube Q2 are MOS EFT.
[0077] In the embodiment, the first switch tube Q1 and the second switch tube Q2 are MOSFETs, thus the gates of the first switch tube Q1 and the second switch tube Q2 share the drive. When the input voltage is connected, the voltage at the source connection point D of the first switch tube Q1 and the second switch tube Q2 is the input voltage due to the existence of the body diode of the first switch tube Q1, and the first switch tube Q1 and the second switch tube Q2 are not turned on, thus the voltage at the source connection point D cannot be transmitted backward. When the input voltage meets the preset range of the first protection circuit 200, the control signal is output, the voltage at the switch connection node C is pulled low, the gate voltage of the first switch tube Q1 and the second switch tube Q2 is less than the source voltage, so that the first switch tube Q1 and the second switch tube Q2 are turned on. When the input voltage does not meet the preset range of the first protection circuit 200, the control signal is not output, the switch connection node C is high, the voltage at the switch connection node C is the input voltage, and the first switch tube Q1 and the second switch tube Q2 are cut off.
[0078] The above describes the embodiments of the application in detail in combination with the drawings, but the application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the application.
Claims
1. A protection circuit for an on-board inverter, characterized in that, include: Switch module (100), first protection circuit (200), and second protection circuit (300); The switch module (100) is connected between the power input terminal and the power output terminal of the protection circuit, and is used to control the on / off state of the protection circuit. The input terminal of the first protection circuit (200) is connected to the power input terminal, and is used to detect the input voltage of the power input terminal, and output a control signal to control the switching module (100) to be turned on when the input voltage meets the preset range; The output terminal of the first protection circuit (200) is connected to the input terminal of the second protection circuit (300). The second protection circuit (300) is connected to the switch module (100). The second protection circuit (300) is used to receive the control signal to control the switch module (100) to turn on and to control the turn-on speed of the switch module (100).
2. The protection circuit according to claim 1, characterized in that, The first protection circuit (200) includes a first voltage divider module (210) and a first driver. The first voltage divider module (210) includes a first voltage divider node. The input terminal of the first driver is connected to the first voltage divider node, and the output terminal of the first driver is connected to the input terminal of the second protection circuit (300). The first driver is used to turn on when the voltage of the first voltage divider node is greater than the reference voltage of the first driver.
3. The protection circuit according to claim 2, characterized in that, The first protection circuit (200) further includes a second voltage divider module (220) and a second driver. The second voltage divider module (220) includes a second voltage divider node. The input terminal of the second driver is connected to the second voltage divider node, and the output terminal of the second driver is connected to the first voltage divider node. The second driver is used to turn on when the voltage of the second voltage divider node is greater than the reference voltage of the second driver. One end of the first voltage divider module (210) and the second voltage divider module (220) are both connected to the power input terminal.
4. The protection circuit according to claim 3, characterized in that, The first protection circuit (200) further includes a voltage limiting adjustment module, which is connected between the first voltage divider node and the output terminal of the second driver. The voltage limiting adjustment module is used to adjust the preset range.
5. The protection circuit according to claim 4, characterized in that, The first voltage divider module (210) includes a third resistor and a fourth resistor, the second voltage divider module (220) includes a first resistor and a second resistor, the first voltage divider node is located between the third resistor and the fourth resistor, the second voltage divider node is located between the first resistor and the second resistor, and the voltage limiting adjustment module includes a seventh resistor, and the preset range is adjusted by changing the resistance value of the seventh resistor.
6. The protection circuit according to claim 1, characterized in that, The second protection circuit (300) includes a first delay module (310) and a switch connection node. The first delay module (310) includes a first capacitor and a fifth resistor. One end of the first capacitor and the fifth resistor are both connected to the switch module (100), and the other end of both are connected to the switch connection node.
7. The protection circuit according to claim 6, characterized in that, The second protection circuit (300) further includes a second delay module (320), which includes a sixth resistor connected between the switch connection node and the output terminal of the first protection circuit (200).
8. The protection circuit according to claim 7, characterized in that, The switching module (100) includes a first switching transistor and a second switching transistor. Both the first switching transistor and the second switching transistor include control pins, and both control pins of the first switching transistor and the second switching transistor are connected to the switch connection node.
9. The protection circuit according to claim 8, characterized in that, Both the first and second switching transistors include two switching pins. One switching pin of the first switching transistor is connected to the power input terminal, and one switching pin of the second switching transistor is connected to the power output terminal. The other switching pins of the first and second switching transistors are connected together, and the conduction directions of the first and second switching transistors are opposite.
10. The protection circuit according to claim 9, characterized in that, The first switch and the second switch are MOSEFT.