Multifunctional input protection circuit and vehicle-mounted charger

Abstract

The utility model describes a vehicle-mounted charger and a multifunctional input protection circuit, which comprise an over-current protection module, a first switch module and a second switch module, a first end of the over-current protection module is connected with a positive input end, and a second end of the over-current protection module is connected with a negative input end; the second end of the overcurrent protection module, the first end of the first switch module, the first end and the second end of the second switch module and the negative output end are mutually connected, the second end of the first switch module is connected with the negative input end, and the third end of the first switch module, the third end of the second switch module and the negative output end are mutually connected; the overcurrent protection module is configured to be switched off when the output current exceeds a preset value, and the second switch module is configured to be switched on when the input voltage exceeds a preset value and enables the first switch module to be switched off. According to the vehicle-mounted charger and the multifunctional input protection circuit, the protection functions of input overcurrent, overvoltage and positive and negative electrode reverse connection can be realized, and the safety and the reliability of the vehicle-mounted charger can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle chargers, in particular to a multifunctional input protection circuit and a vehicle charger. Background Art

[0002] my country's car ownership has reached hundreds of millions, and the demand for on-board chargers has correspondingly increased dramatically. Current types of on-board chargers include cigarette lighter and embedded models. They have evolved from a single USB-A port to dual USB-A ports, one USB-A and one USB-C port, and dual USB-C ports. Power has also increased from 10W to 18W, 30W, 45W, 65W, and 100W. They are also becoming increasingly smaller and more aesthetically pleasing.

[0003] As car charging power increases, the requirements for car charger protection circuits are also becoming increasingly stringent. However, currently available on-board chargers generally only have output protection circuits, and very few have input protection circuits. However, as car charger sales gradually increase, and because car chargers are used in cars, customers are demanding higher safety, and therefore the demand for input protection functions is also increasing accordingly. Utility Model Content

[0004] The utility model aims to provide a square vehicle charger and a multifunctional input protection circuit, including input overcurrent, overvoltage and positive and negative pole reverse connection protection functions, aiming to improve the safety and reliability of the vehicle charger.

[0005] To this end, the first aspect of the present invention provides a multifunctional input protection circuit, including an overcurrent protection module, a first switch module and a second switch module, the first end of the overcurrent protection module is connected to the positive input end, the second end of the overcurrent protection module, the first end of the first switch module, the first end and the second end of the second switch module, and the positive output end are interconnected, the second end of the first switch module is connected to the negative input end, the third end of the first switch module, the third end of the second switch module, and the negative output end are interconnected, the overcurrent protection module is configured to disconnect when the output current exceeds a preset value, the second switch module is configured to turn on and turn off the first switch module when the input voltage exceeds a preset value, and the first switch module is configured to turn off when the positive input end and the negative input end are reversed.

[0006] In the multifunctional input protection circuit involved in the present invention, the overcurrent protection module is configured to disconnect when the output current exceeds a preset value, thereby realizing overcurrent protection; the second switch module is configured to turn on and turn off the first switch module when the input voltage exceeds a preset value, thereby realizing overvoltage protection; the first switch module is configured to turn off when the positive input terminal and the negative input terminal are reversed, thereby realizing the positive and negative polarity reverse connection protection function.

[0007] In addition, in the multifunctional input protection circuit involved in the first aspect of the present utility model, optionally, the overcurrent protection module includes a fuse, and the fuse blows when the output current exceeds the fuse limit.

[0008] In addition, in the multifunctional input protection circuit involved in the first aspect of the present invention, optionally, the second switch module includes a voltage regulator diode and at least one transistor, the voltage regulator diode is used to detect the input voltage, and the transistor is turned on to disconnect the first switch module when the voltage regulator diode detects overvoltage.

[0009] In addition, in the multifunctional input protection circuit involved in the first aspect of the present invention, optionally, the first switch module includes at least two MOS transistors, and the MOS transistors are used to shut down when it is detected that the positive input terminal and the negative input terminal are reversely connected.

[0010] In addition, in the multifunctional input protection circuit involved in the first aspect of the present invention, optionally, it also includes a filtering module, a first end of the filtering module is connected to the positive output end, and the other end of the filtering module is connected to the negative output end, and the filtering module is configured to filter out ripples in the circuit.

[0011] In addition, in the multi-functional input protection circuit involved in the first aspect of the present invention, optionally, the second switch module includes a first resistor, the voltage regulator diode and an NPN transistor, the first end of the first resistor is connected to the second end of the overcurrent protection module, the second end of the first resistor is connected to the cathode of the voltage regulator diode, the anode of the voltage regulator diode is connected to the base of the NPN transistor, the collector of the NPN transistor is connected to the first end of the first switch module, and the emitter of the NPN transistor is connected to the third end of the first switch module.

[0012] In addition, in the multi-functional input protection circuit involved in the first aspect of the present utility model, optionally, the first switch module includes a first NMOS tube, a second NMOS tube, a second resistor and a diode, the first end of the second resistor is connected to the second end of the overcurrent protection module, the second end of the second resistor is connected to the positive electrode of the diode, the negative electrode of the diode, the gate of the first NMOS tube, and the gate of the second NMOS tube are interconnected, the source of the first NMOS tube is connected to the negative input end, the drain of the first NMOS tube is connected to the drain of the second NMOS tube, and the source of the second NMOS tube is connected to the negative output end.

[0013] In addition, in the multifunctional input protection circuit involved in the first aspect of the present utility model, optionally, the filtering module includes at least one filtering capacitor.

[0014] In addition, in the multifunctional input protection circuit involved in the first aspect of the present utility model, optionally, the filtering module includes a first filter capacitor and a second filter capacitor, the positive electrode of the first filter capacitor, the positive electrode of the second filter capacitor, and the positive output end are interconnected, and the negative electrode of the first filter capacitor, the negative electrode of the second filter capacitor, and the negative output end are interconnected.

[0015] A second aspect of the present invention provides a vehicle charger, which includes the multifunctional input protection circuit described in the first aspect.

[0016] The vehicle charger and the multifunctional input protection circuit according to the present invention can realize input overcurrent, overvoltage and positive and negative polarity reverse connection protection functions, and can improve the safety and reliability of the vehicle charger. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will now be explained in further detail, by way of example only, with reference to the accompanying drawings.

[0018] Figure 1 1 is a functional module diagram showing a multifunctional input protection circuit according to an example of the present utility model.

[0019] Figure 2 1 is a circuit diagram showing a multifunctional input protection circuit according to an example of the present invention. DETAILED DESCRIPTION

[0020] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. In the following description, identical components will be assigned identical reference numerals, and duplicate descriptions will be omitted. In addition, the accompanying drawings are merely schematic, and the proportions of the dimensions of the components or the shapes of the components may differ from the actual ones.

[0021] It should be noted that the terms "include" and "have" and any variations thereof in the present invention, such as a process, method, system, product or device that includes or has a series of steps or units, are not necessarily limited to those steps or units clearly listed, but may include or have other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0022] Reference Figure 1 The present invention provides a multifunctional input protection circuit. In some embodiments, the multifunctional input protection circuit includes at least one of an overcurrent protection module 1 , a first switch module 3 , and a second switch module 2 .

[0023] In some embodiments, the first terminal of the overcurrent protection module is connected to the positive input terminal INPUT+; the second terminal of the overcurrent protection module, the first terminal of the first switch module 3, the first and second terminals of the second switch module 2, and the positive output terminal OUT+ are interconnected; the second terminal of the first switch module 3 is connected to the negative input terminal INPUT-; the third terminal of the first switch module 3, the third terminal of the second switch module 2, and the negative output terminal OUT- are interconnected. The overcurrent protection module 1 can be configured to disconnect when the output current exceeds a preset value. The second switch module 2 can be configured to turn on and shut down the first switch module 2 when the input voltage exceeds a preset value. The first switch module 3 can be configured to shut down when the positive and negative input terminals are reversed.

[0024] In the multifunctional input protection circuit involved in the present invention, the overcurrent protection module 1 is configured to disconnect when the output current exceeds a preset value, thereby realizing overcurrent protection; the second switch module 2 is configured to turn on and turn off the first switch module 3 when the input voltage exceeds a preset value, thereby realizing overvoltage protection; the first switch module 3 is configured to turn off when the positive input terminal INPUT+ and the negative input terminal INPUT- are reversed, thereby realizing the positive and negative polarity reverse connection protection function.

[0025] In some embodiments, the overcurrent protection module 1 includes a fuse F1 that can be blown when the output current exceeds a fuse limit.

[0026] In some embodiments, the second switch module 2 may include a voltage regulator diode and at least one transistor. The voltage regulator diode may be used to detect the input voltage, and the transistor may be turned on to disconnect the first switch module when the voltage regulator diode detects an overvoltage.

[0027] In some embodiments, the first switch module includes at least two MOS transistors, which are configured to shut down when detecting reverse connection between the positive input terminal and the negative input terminal. Using MOS transistors for reverse connection protection can take advantage of their low internal resistance and low loss.

[0028] In some embodiments, the multifunctional input protection circuit may further include a filter module 4. A first terminal of the filter module 4 is connected to the positive output terminal OUT+, and another terminal of the filter module 4 is connected to the negative output terminal OUT-. The filter module may be configured to filter out ripples in the circuit.

[0029] In some embodiments, the second switch module 2 may include a first resistor R1, a Zener diode ZD1, and an NPN transistor Q3. The first end of the first resistor R1 is connected to the second end of the overcurrent protection module 1, the second end of the first resistor R1 is connected to the cathode of the Zener diode ZD1, the anode of the Zener diode ZD1 is connected to the base of the NPN transistor Q3, the collector of the NPN transistor Q3 is connected to the first end of the first switch module 3, and the emitter of the NPN transistor Q3 is connected to the third end of the first switch module 3. The first resistor R1 is an upper bias resistor that can power the Zener diode ZD1. When the input voltage is higher than the regulated voltage value of the Zener diode ZD1, it can provide sufficient current to the Zener diode ZD1. When the input voltage is less than the voltage regulation value of the Zener diode ZD1, the Zener diode ZD1 has no reverse Zener current, and the NPN transistor Q3 will not conduct due to the lack of drive current. When the input voltage is greater than the voltage regulation value of the Zener diode ZD1, the Zener diode ZD1 has a reverse Zener current, and the NPN transistor Q3 conducts due to the drive current.

[0030] In some embodiments, the first switch module 3 may include a first NMOS transistor Q1, a second NMOS transistor Q2, a second resistor R2, and a diode D1. The first end of the second resistor R2 is connected to the second end of the overcurrent protection module 1 (or fuse F1), the second end of the second resistor R2 is connected to the positive electrode of the diode D1, the negative electrode of the diode D1, the gate of the first NMOS transistor Q1, and the gate of the second NMOS transistor Q2 are interconnected, the source of the first NMOS transistor Q1 is connected to the negative input terminal, the drain of the first NMOS transistor Q1 is connected to the drain of the second NMOS transistor Q2, and the source of the second NMOS transistor Q2 is connected to the negative output terminal OUT-. The second resistor R2 is an upper bias resistor that can provide a driving voltage to the first NMOS transistor Q1 and the second NMOS transistor Q2. When the input voltage comes in, it can provide sufficient voltage to turn on the first NMOS transistor Q1 and the second NMOS transistor Q2. The diode D1 can prevent the leakage voltage from forming a loop when the positive and negative poles are reversed, causing the first NMOS transistor Q1 and the second NMOS transistor Q2 to turn on, rendering the reverse connection protection function ineffective.

[0031] In some embodiments, the collector of the NPN transistor Q3 , the second end of the second resistor R2 , and the anode of the diode D1 are interconnected.

[0032] In some embodiments, the emitter of the NPN transistor Q3 is connected to the gate of the second NMOS transistor Q2 .

[0033] In some embodiments, the filtering module 4 may include at least one filtering capacitor.

[0034] In some embodiments, the filter module includes a first filter capacitor CE1 and a second filter capacitor CE2. The positive electrode of the first filter capacitor CE1, the positive electrode of the second filter capacitor CE2, and the positive output terminal OUT+ are interconnected, and the negative electrode of the first filter capacitor CE1, the negative electrode of the second filter capacitor CE2, and the negative output terminal OUT- are interconnected.

[0035] The utility model also provides a vehicle charger, which includes the multifunctional input protection circuit as described above.

[0036] The vehicle charger and the multifunctional input protection circuit according to the present invention can realize input overcurrent, overvoltage and positive and negative polarity reverse connection protection functions, and can improve the safety and reliability of the vehicle charger.

[0037] Although the present invention has been described in detail above with reference to the accompanying drawings and examples, it should be understood that the above description does not limit the present invention in any form. Those skilled in the art may modify and alter the present invention as needed without departing from the spirit and scope of the present invention, and such modifications and alterations are intended to fall within the scope of the present invention.

Claims

1. A multifunctional input protection circuit, characterized in that: The invention comprises an overcurrent protection module, a first switch module and a second switch module, wherein the first end of the overcurrent protection module is connected to the positive input end, the second end of the overcurrent protection module, the first end of the first switch module, the first end and the second end of the second switch module, and the positive output end are interconnected, the second end of the first switch module is connected to the negative input end, the third end of the first switch module, the third end of the second switch module, and the negative output end are interconnected, the overcurrent protection module is configured to be disconnected when the output current exceeds a preset value, the second switch module is configured to be turned on and the first switch module is turned off when the input voltage exceeds a preset value, and the first switch module is configured to be turned off when the positive input end and the negative input end are reversed.

2. The multifunctional input protection circuit according to claim 1, characterized in that: The overcurrent protection module includes a fuse, which melts when the output current exceeds the fuse limit.

3. The multifunctional input protection circuit according to claim 1, characterized in that: The second switch module includes a voltage-stabilizing diode and at least one transistor. The voltage-stabilizing diode is used to detect input voltage. The transistor is turned on to disconnect the first switch module when the voltage-stabilizing diode detects overvoltage.

4. The multifunctional input protection circuit according to claim 1, characterized in that: The first switch module includes at least two MOS transistors, and the MOS transistors are used to be turned off when it is detected that the positive input terminal and the negative input terminal are reversely connected.

5. The multifunctional input protection circuit according to any one of claims 1 to 4, characterized in that: It also includes a filtering module, a first end of the filtering module is connected to the positive output end, and the other end of the filtering module is connected to the negative output end, and the filtering module is configured to filter out ripples in the circuit.

6. The multifunctional input protection circuit according to claim 3, characterized in that: The second switch module includes a first resistor, the voltage regulator diode and an NPN transistor, the first end of the first resistor is connected to the second end of the overcurrent protection module, the second end of the first resistor is connected to the cathode of the voltage regulator diode, the anode of the voltage regulator diode is connected to the base of the NPN transistor, the collector of the NPN transistor is connected to the first end of the first switch module, and the emitter of the NPN transistor is connected to the third end of the first switch module.

7. The multifunctional input protection circuit according to claim 4, characterized in that: The first switch module includes a first NMOS transistor, a second NMOS transistor, a second resistor and a diode, the first end of the second resistor is connected to the second end of the overcurrent protection module, the second end of the second resistor is connected to the anode of the diode, the cathode of the diode, the gate of the first NMOS transistor, and the gate of the second NMOS transistor are interconnected, the source of the first NMOS transistor is connected to the negative input terminal, the drain of the first NMOS transistor is connected to the drain of the second NMOS transistor, and the source of the second NMOS transistor is connected to the negative output terminal.

8. The multifunctional input protection circuit according to claim 5, characterized in that: The filtering module includes at least one filtering capacitor.

9. The multifunctional input protection circuit according to claim 8, characterized in that: The filtering module includes a first filter capacitor and a second filter capacitor, the positive electrode of the first filter capacitor, the positive electrode of the second filter capacitor, and the positive output end are interconnected, and the negative electrode of the first filter capacitor, the negative electrode of the second filter capacitor, and the negative output end are interconnected.

10. A vehicle charger, characterized in that: The invention comprises the multifunctional input protection circuit according to any one of claims 1 to 9.

Images