CN219372005U - Voltage and current limiting circuit and charger - Google Patents
Voltage and current limiting circuit and charger Download PDFInfo
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- CN219372005U CN219372005U CN202320282263.0U CN202320282263U CN219372005U CN 219372005 U CN219372005 U CN 219372005U CN 202320282263 U CN202320282263 U CN 202320282263U CN 219372005 U CN219372005 U CN 219372005U
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Abstract
The utility model discloses a voltage and current limiting circuit and a charger, which comprise a first switch unit, a second switch unit and a current limiting unit, wherein the first switch unit is connected to a loop between a power supply and an integrated circuit and is used for controlling the on-off of power supply to the integrated circuit; the input end of the second switch unit is connected with the power supply, the output end of the second switch unit is connected with the control end of the first switch unit, and the second switch unit is used for controlling the on-off of the first switch unit; the current limiting unit is connected to a loop between the power supply and the integrated circuit and is used for limiting output current; when the power supply is over-voltage, the second switch unit is turned on to further control the first switch unit to be turned off so as to cut off the power supply of the power supply to the integrated circuit. The voltage and current limiting circuit disclosed by the utility model can prevent the integrated circuit from being burnt out due to overlarge input current, and has the advantages of simple structure and high safety.
Description
Technical Field
The present disclosure relates to electronic circuits, and particularly to a voltage and current circuit limiting circuit and a charger.
Background
Today, integrated circuit technology is rapidly advancing, integrated circuits are also slowly replacing analog circuits, and integrated circuits are very widely applied in the circuits. However, when using an integrated circuit (Integrated Circuit, i.e., IC), the most important parameters are the operating voltage and operating current of the IC, when the input voltage of the power supply exceeds the operating voltage of the IC, the IC is burned out, resulting in failure of the entire circuit; similarly, when the current in the circuit exceeds the operating current of the IC, the IC is burned. Therefore, the operating voltage and operating current of the IC need to be limited to prevent the IC from being burned out. The existing voltage and current limiting circuit cannot limit larger current, and when the current is too large, the IC is easy to burn out, so that the circuit is invalid, and potential safety hazards exist in the use process.
Accordingly, in order to solve the above-mentioned problems, the present utility model provides a voltage-current limiting circuit and a charger capable of limiting a large current.
Disclosure of Invention
The utility model provides a voltage-limited current circuit and a charger, and aims to solve the problem that an existing integrated circuit is easy to burn out due to overlarge current.
In order to solve the above technical problem, an aspect of the present utility model provides a voltage-current limiting circuit, which includes: the first switch unit is connected to a loop between the power supply and the integrated circuit and is used for controlling the on-off of power supply to the integrated circuit; the input end of the second switch unit is connected with the power supply, the output end of the second switch unit is connected with the control end of the first switch unit, and the second switch unit is used for controlling the on-off of the first switch unit; the current limiting unit is connected to a loop between the power supply and the integrated circuit and is used for limiting output current; when the power supply is over-voltage, the second switch unit is turned on to further control the first switch unit to be turned off so as to cut off the power supply of the power supply to the integrated circuit.
Further, the current limiting unit comprises a sixth resistor and at least one fuse, one end of the sixth resistor is connected with the output end of the first switch unit, the other end of the sixth resistor is connected with one end of the fuse, and the other end of the fuse is grounded.
Further, the current limiting unit comprises a first fuse and a second fuse, one end of the first fuse is connected with the sixth resistor, the other end of the first fuse is grounded, and the second fuse is connected with the first fuse in parallel.
Further, the current limiting unit further comprises a load, one end of the load is connected with the output end of the first switch unit, the other end of the load is connected with the first fuse and the second fuse, and the load is connected with the sixth resistor in parallel.
Further, the first switch unit comprises a first switch tube, a third resistor, a fourth resistor and a fifth resistor, one end of the third resistor is connected with a first connecting end of the first switch tube, and the other end of the third resistor is connected with a second connecting end of the first switch tube and the power supply; one end of the fourth resistor is connected with the first connecting end of the first switching tube, and the other end of the fourth resistor is connected with the output end of the second switching unit; one end of the fifth resistor is connected with the first connecting end of the first switching tube, the other end of the fifth resistor is grounded, and the third connecting end of the first switching tube is connected with the current limiting unit.
Further, the second switching unit comprises a zener diode and a second switching tube, a first connecting end of the second switching tube is connected with a cathode of the zener diode, a second connecting end of the second switching tube is connected with the power supply and a second connecting end of the first switching tube, and a third connecting end of the second switching tube is connected with the fourth resistor.
Further, the second switch unit further comprises a first resistor and a second resistor, one end of the first resistor is connected with the power supply, and the other end of the first resistor is connected with the cathode of the zener diode; one end of the second resistor is connected with the first connecting end of the second switching tube, and the other end of the second resistor is connected with the cathode of the zener diode.
Further, the second switch unit further comprises a first capacitor, one end of the first capacitor is connected with the power supply, and the other end of the first capacitor is connected with the first connecting end of the second switch tube.
Further, the first switching tube is a PMOS tube, and the second switching tube is a PNP triode.
The utility model also provides a charger, which is provided with the voltage and current limiting circuit, wherein the output end of the voltage and current limiting circuit is used for being connected with an integrated circuit so as to provide working voltage and current for the integrated circuit.
According to the voltage and current limiting circuit and the charger disclosed by the utility model, when the power supply is over-voltage, the second switch unit is conducted to control the first switch unit to be disconnected so as to cut off the power supply of the power supply to the integrated circuit, and the current limiting unit limits the output current when the current is over-large, so that the current input to the integrated circuit is limited within the rated working current range, and the integrated circuit can be prevented from being burnt due to the over-large input current. The voltage and current limiting circuit disclosed by the utility model solves the problem that the existing integrated circuit is easy to burn out due to overlarge current.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a voltage-current limiting circuit according to an embodiment of the present utility model;
FIG. 2 is a schematic circuit diagram of a voltage-current limiting circuit according to an embodiment of the present utility model;
fig. 3 is a schematic structural diagram of a charger according to an embodiment of the present utility model.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the utility model herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
Fig. 1 to 3 illustrate an embodiment of a voltage-current limiting circuit according to the present utility model. The voltage-current limiting circuit 10 of the present embodiment is used for an electronic product requiring both voltage limitation and current limitation, such as a charger 100, and includes a first switching unit 11, a second switching unit 12, and a current limiting unit 13, where the first switching unit 11 is connected to a loop between a power source VCC and an integrated circuit 20, and the first switching unit 11 is used for controlling on/off of power supplied to the integrated circuit 20; the input end of the second switch unit 12 is connected with the power supply VCC, the output end of the second switch unit 12 is connected with the control end of the first switch unit 11, and the second switch unit 12 is used for controlling the on-off of the first switch unit 11; the current limiting unit 13 is connected to a loop between the power supply VCC and the integrated circuit 20, and the current limiting unit 13 is used for limiting the output current; when the power VCC is over-voltage, the second switch unit 12 is turned on to control the first switch unit 11 to be turned off so as to cut off the power supply VCC from the integrated circuit 20. In the embodiment, when the power supply is over-voltage, the second switch unit is conducted to control the first switch unit to be disconnected so as to cut off the power supply for the integrated circuit, and the current limiting unit limits the output current when the current is over-large, so that the current input into the integrated circuit is limited in the rated working current range, the integrated circuit can be prevented from being burnt out due to the over-large input current, and the voltage-current limiting circuit is simple in structure and high in safety.
In an embodiment, for example, in this embodiment, the current limiting unit 13 includes a sixth resistor R6 and at least one fuse, one end of the sixth resistor R6 is connected to the output end of the first switch unit 11, the other end is connected to one end of the fuse, and the other end of the fuse is grounded. In this embodiment, the fuse is a recoverable fuse, the sixth resistor R6 is a light load, and the sixth resistor R6 is connected in series with the recoverable fuse to perform a voltage division protection function. When the current output by the first switch unit 11 exceeds the set current, the recoverable fuse is opened, so that the circuit is opened to stop outputting; when the current and the temperature of the recoverable fuse drop, the recoverable fuse returns to the pre-disconnection state and resumes operation, so that the recoverable fuse can be repeatedly used, and resources and cost are saved.
In an embodiment, for example, in this embodiment, the current limiting unit 13 includes a first fuse RS1, a second fuse RS2, and a load RL, where one end of the first fuse RS1 is connected to the sixth resistor R6, and the other end is grounded, and the second fuse RS2 is connected in parallel to the first fuse RS 1. One end of the load RL is connected to the output end of the first switch unit 11, the other end is connected to the first fuse RS1 and the second fuse RS2, and the load RL is connected in parallel to the sixth resistor R6. Specifically, as shown in fig. 2, by connecting the second fuse RS2 in parallel with the first fuse RS1, a larger current can be limited. Alternatively, an appropriate number of fuses may be selected in parallel with the first fuse RS1 to limit a larger current according to actual needs. More specifically, both ends of the load RL are used as output terminals for connection with the integrated circuit 20 to supply a suitable current to the integrated circuit 20, thereby preventing the output current from exceeding the current required by the integrated circuit 20, resulting in burning of the integrated circuit 20.
In an embodiment, for example, in this embodiment, the first switching unit 11 includes a first switching tube, a third resistor R3, a fourth resistor R4, and a fifth resistor R5, where one end of the third resistor R3 is connected to a first connection end of the first switching tube, and the other end is connected to a second connection end of the first switching tube and the power VCC; one end of the fourth resistor R4 is connected with the first connecting end of the first switching tube, and the other end of the fourth resistor R4 is connected with the output end of the second switching unit 12; one end of the fifth resistor R5 is connected with the first connection end of the first switching tube, the other end of the fifth resistor R5 is grounded, and the third connection end of the first switching tube is connected with the current limiting unit 13. Specifically, the first switching tube is a PMOS tube Q1, the first connection end of the first switching tube is a gate of the PMOS tube Q1, the second connection end of the first switching tube is a source of the PMOS tube Q1, and the third connection end of the first switching tube is a drain of the PMOS tube Q1. More specifically, one end of the third resistor R3 is connected to the gate of the PMOS transistor Q1, and the other end is connected to the source of the PMOS transistor Q1 and the power VCC; one end of the fourth resistor R4 is connected with the grid electrode of the PMOS tube Q1, and the other end of the fourth resistor R4 is connected with the output end of the second switch unit 12; one end of the fifth resistor R5 is connected with the gate of the PMOS tube Q1, the other end of the fifth resistor R5 is grounded, and the drain of the PMOS tube Q1 is connected with the current limiting unit 13.
In an embodiment, for example, in this embodiment, the second switching unit 12 includes a zener diode D1 and a second switching tube, a first connection end of the second switching tube is connected to a cathode of the zener diode D1, a second connection end of the second switching tube is connected to the power VCC and a second connection end of the first switching tube, and a third connection end of the second switching tube is connected to the fourth resistor R4. Specifically, the second switching tube is a PNP triode Q2, the first connection end of the second switching tube is a base electrode of the PNP triode Q2, the second connection end of the second switching tube is an emitter electrode of the PNP triode Q2, and the third connection end of the second switching tube is a collector electrode of the PNP triode Q2. More specifically, the base of the PNP transistor Q2 is connected to the cathode of the zener diode D1, the emitter of the PNP transistor Q2 is connected to the power source VCC and the source of the PMOS transistor Q1, and the collector of the PNP transistor Q2 is connected to the fourth resistor R4. It should be noted that, in this embodiment, in order to achieve the fast turn-on of the PNP transistor Q2, a large voltage difference needs to be formed between the gate and the source of the PMOS transistor Q1, for which the third resistor R3 needs to have a large resistance, for example, a resistance of 100kΩ; while the resistance of the fourth resistor R4 needs to be 100 times smaller than the resistance of the third resistor R3, the resistance of the fifth resistor R5 needs to be 10 times smaller than the resistance of the third resistor R3. In other embodiments, the third resistor R3 may also be a resistor with a suitable resistance value according to actual needs, and the resistance values of the fourth resistor R4 and the fifth resistor R5 may also be set according to actual needs, for example, the resistance value of the fourth resistor R4 is 80 times smaller than the resistance value of the third resistor R3. It should be further noted that, in this embodiment, the PNP transistor Q2 is an LMBT4403 transistor; the PMOS tube Q1 is a DMP3098MOS tube. Understandably, in other embodiments, other types of transistors or MOS transistors may be selected according to actual needs, which will not be described herein.
In an embodiment, for example, in this embodiment, the first switch unit 11 further includes a first resistor R1, a second resistor R2, and a first capacitor C1, where one end of the first resistor R1 is connected to the power VCC, and the other end is connected to the cathode of the zener diode D1; one end of the second resistor R2 is connected with the first connecting end of the second switching tube, and the other end of the second resistor R2 is connected with the cathode of the zener diode D1. One end of the first capacitor C1 is connected with the power supply VCC, and the other end of the first capacitor C is connected with the first connecting end of the second switching tube. Specifically, one end of the second resistor R2 is connected to the base of the PNP transistor Q2, and the other end is connected to the cathode of the zener diode D1. One end of the first capacitor C1 is connected with the power supply VCC, and the other end of the first capacitor C is connected with the base electrode of the PNP triode Q2. More specifically, the first resistor R1 is a current limiting resistor of the zener diode D1, and the second resistor R2 is a current limiting resistor of the PNP transistor Q2, so as to protect the zener diode D1 and the PNP transistor Q2. The first capacitor C1 is connected between the power VCC and the base of the PNP transistor Q2, so as to speed up the conduction of the PNP transistor Q2. It should be noted that, in this embodiment, the resistance of the first resistor R1 may be 1kΩ to 10kΩ, the resistance of the second resistor R2 may be 1kΩ to 3kΩ, the capacitance of the first capacitor C1 is selected to be nf-level, and it is understood that in other embodiments, the first resistor R1 and the second resistor may be selected to be other resistance values according to actual requirements, and the first capacitor C1 may also be selected to be other capacitance values according to actual requirements.
For ease of understanding, the operation of the voltage-current limiting circuit 10 will now be described as follows:
when the power VCC is lower than or equal to a normal voltage, for example, the normal voltage is 15V, the zener diode D1 stabilizes the power VCC at 15V, and at this time, since the voltage difference between the base and the emitter of the PNP transistor Q2 is very small, the PNP transistor Q2 is not turned on, the voltage of the 15V is divided by the third resistor R3 and the fifth resistor R5, the gate voltage of the PMOS transistor Q1 is 1.36V, the voltage difference between the gate and the source is 13.64V, the PMOS transistor is turned on, the first switching unit 11 can normally output a voltage to the current limiting unit 13, and when the current in the current limiting unit 13 exceeds a set current value, the fuse can be restored to be turned off, so that the current limiting unit 13 stops outputting to protect the integrated circuit 20; when the current and temperature in the current limiting unit 13 drop, the recoverable fuse can be recovered to a pre-disconnection state, and the operation is recovered, so that the recoverable fuse can be reused.
When the power VCC is higher than a normal voltage, for example, the normal voltage is 15V, the power VCC is 17V, the zener diode D1 stabilizes the power VCC at 15V, the base voltage of the PNP transistor Q2 is 15V, the emitter voltage of the PNP transistor Q2 is 17V, the voltage difference between the base and the emitter of the PNP transistor Q2 is 2V, the PNP transistor Q2 is turned on, the gate voltage of the PMOS transistor Q1 is 16.4V after the 17V voltage is divided by the fourth resistor R4 and the fifth resistor R5, the source voltage of the PMOS transistor Q1 is 17V, the voltage difference between the gate and the source is 0.6V, the PMOS transistor Q1 is not turned on, and the first switch unit 11 is turned on and has no output, thereby playing a role of protecting the integrated circuit 20.
In an embodiment, for example, the present embodiment, a charger is further provided, referring to fig. 3, the charger 100 is designed with the voltage-current limiting circuit 10, where an output terminal of the voltage-current limiting circuit 10 is used to connect with the integrated circuit 20 to provide an operating voltage and current to the integrated circuit 20. Specifically, the charger 100 is a vehicle-mounted charger. In this embodiment, the voltage and current limiting circuit 10 limits the voltage and current input to the integrated circuit 20 within the rated range, so as to prevent the integrated circuit 20 from being burned out due to excessive voltage or input current.
According to the voltage and current limiting circuit provided by the utility model, when the power supply is over-voltage, the second switch unit is conducted to control the first switch unit to be disconnected so as to cut off the power supply of the power supply to the integrated circuit, and when the current is over-large, the current limiting unit limits the output current, so that the current input to the integrated circuit is limited in the rated working current range, and the integrated circuit can be prevented from being burnt due to the over-large input current. The voltage and current limiting circuit disclosed by the utility model solves the problem that the existing integrated circuit is easy to burn out due to overlarge current.
While the utility model has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the utility model. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.
Claims (10)
1. A voltage-current limiting circuit, comprising:
the first switch unit is connected to a loop between the power supply and the integrated circuit and is used for controlling the on-off of power supply to the integrated circuit;
the input end of the second switch unit is connected with the power supply, the output end of the second switch unit is connected with the control end of the first switch unit, and the second switch unit is used for controlling the on-off of the first switch unit;
the current limiting unit is connected to a loop between the power supply and the integrated circuit and is used for limiting output current;
when the power supply is over-voltage, the second switch unit is turned on to further control the first switch unit to be turned off so as to cut off the power supply of the power supply to the integrated circuit.
2. The voltage-current limiting circuit of claim 1, wherein the current limiting unit comprises a sixth resistor and at least one fuse, one end of the sixth resistor is connected to the output terminal of the first switching unit, the other end is connected to one end of the fuse, and the other end of the fuse is grounded.
3. The voltage-current limiting circuit according to claim 2, wherein the current limiting unit includes a first fuse and a second fuse, one end of the first fuse is connected to the sixth resistor, the other end is grounded, and the second fuse is connected in parallel with the first fuse.
4. A voltage-current limiting circuit according to claim 3, wherein the current limiting unit further comprises a load, one end of the load is connected to the output terminal of the first switching unit, the other end is connected to the first fuse and the second fuse, and the load is connected in parallel to the sixth resistor.
5. The voltage-current limiting circuit according to claim 1, wherein the first switching unit comprises a first switching tube, a third resistor, a fourth resistor and a fifth resistor, one end of the third resistor is connected with a first connection end of the first switching tube, and the other end is connected with a second connection end of the first switching tube and the power supply; one end of the fourth resistor is connected with the first connecting end of the first switching tube, and the other end of the fourth resistor is connected with the output end of the second switching unit; one end of the fifth resistor is connected with the first connecting end of the first switching tube, the other end of the fifth resistor is grounded, and the third connecting end of the first switching tube is connected with the current limiting unit.
6. The voltage-current limiting circuit of claim 5, wherein the second switching unit comprises a zener diode and a second switching tube, a first connection terminal of the second switching tube is connected to a cathode of the zener diode, a second connection terminal of the second switching tube is connected to the power supply and a second connection terminal of the first switching tube, and a third connection terminal of the second switching tube is connected to the fourth resistor.
7. The voltage-current limiting circuit of claim 6, wherein the second switching unit further comprises a first resistor and a second resistor, one end of the first resistor is connected to the power supply, and the other end is connected to the cathode of the zener diode; one end of the second resistor is connected with the first connecting end of the second switching tube, and the other end of the second resistor is connected with the cathode of the zener diode.
8. The voltage-current limiting circuit of claim 7, wherein the second switching unit further comprises a first capacitor having one end connected to the power supply and the other end connected to the first connection terminal of the second switching tube.
9. The voltage-current limiting circuit of claim 6, wherein the first switching tube is a PMOS tube and the second switching tube is a PNP transistor.
10. A charger provided with a voltage and current limiting circuit as claimed in any one of claims 1 to 9, the output of the voltage and current limiting circuit being arranged to be connected to an integrated circuit for providing operating voltage and current to the integrated circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320282263.0U CN219372005U (en) | 2023-02-14 | 2023-02-14 | Voltage and current limiting circuit and charger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320282263.0U CN219372005U (en) | 2023-02-14 | 2023-02-14 | Voltage and current limiting circuit and charger |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219372005U true CN219372005U (en) | 2023-07-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320282263.0U Active CN219372005U (en) | 2023-02-14 | 2023-02-14 | Voltage and current limiting circuit and charger |
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| Country | Link |
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| CN (1) | CN219372005U (en) |
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- 2023-02-14 CN CN202320282263.0U patent/CN219372005U/en active Active
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