CN214045014U - Voltage protection circuit and power input device - Google Patents
Voltage protection circuit and power input device Download PDFInfo
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- CN214045014U CN214045014U CN202023196558.1U CN202023196558U CN214045014U CN 214045014 U CN214045014 U CN 214045014U CN 202023196558 U CN202023196558 U CN 202023196558U CN 214045014 U CN214045014 U CN 214045014U
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Abstract
The utility model discloses a voltage protection circuit and power input device relates to electron technical field. The voltage protection circuit comprises an overvoltage protection circuit, a switch circuit and a reverse protection circuit. The switching circuit is used for controlling the connection or disconnection of a loop between a preset first voltage input end and the reverse protection circuit; the overvoltage protection circuit is used for detecting a first voltage of a preset first voltage input end and controlling the switch circuit to be switched off when the first voltage is greater than a first preset threshold value; and the reverse protection circuit is used for detecting a second voltage of the preset second voltage input end and controlling the switching-on or switching-off of a loop between the switching circuit and the preset voltage output end according to the second voltage. The utility model realizes the overvoltage protection of the input voltage through the overvoltage protection circuit, and cuts off the input when the input voltage is too high; meanwhile, reverse voltage protection is realized through the reverse protection circuit, and when the voltage is reversely connected, the input is cut off, so that the safety of the back-end circuit is ensured.
Description
Technical Field
The utility model relates to the field of electronic technology, especially, relate to a voltage protection circuit and power input device.
Background
Generally, the electric equipment can normally work only under proper working voltage, and the service life can also be delayed. However, the input power is susceptible to environmental changes, which may cause fluctuations in the operating voltage of the electric device, thereby adversely affecting the electric device. Therefore, how to avoid the easy influence of the operating voltage of the electric equipment is a technical problem to be solved urgently.
The above is only for the purpose of assisting understanding of the technical solutions of the present invention, and does not represent an admission that the above is the prior art.
SUMMERY OF THE UTILITY MODEL
A primary object of the present invention is to provide a voltage protection circuit and power input device, which aims to solve the technical problem that the working voltage of the electric equipment in the prior art is susceptible to influence.
In order to achieve the above object, the present invention provides a voltage protection circuit, the voltage protection circuit includes: the overvoltage protection circuit, the switch circuit and the reverse protection circuit; the input end of the overvoltage protection circuit is connected with a preset first voltage input end, the first output end of the overvoltage protection circuit is connected with the control end of the switch circuit, the second output end of the overvoltage protection circuit is connected with a preset second voltage input end, the input end of the switch circuit is connected with the preset first voltage input end, the first output end of the switch circuit is connected with the first input end of the reverse protection circuit, the second output end of the switch circuit is connected with the preset second voltage input end, the second input end of the reverse protection circuit is connected with the preset second voltage input end, and the output end of the reverse protection circuit is connected with the preset voltage output end;
the switch circuit is used for controlling the loop between the preset first voltage input end and the reverse protection circuit to be switched on or switched off;
the overvoltage protection circuit is used for detecting a first voltage of the preset first voltage input end and controlling the switching circuit to be switched off when the first voltage is greater than a first preset threshold value;
the reverse protection circuit is used for detecting a second voltage of the preset second voltage input end and controlling the circuit between the switch circuit and the preset voltage output end to be switched on or switched off according to the second voltage.
Optionally, the switching circuit includes a first MOS transistor and a voltage dropping circuit; a first input end of the voltage reduction circuit is connected with the preset first voltage input end, a second input end of the voltage reduction circuit is connected with a first output end of the overvoltage protection circuit, a first output end of the voltage reduction circuit is connected with a grid electrode of the first MOS tube, and a second output end of the voltage reduction circuit is connected with the preset second voltage input end; the source electrode of the first MOS tube is connected with the preset first voltage input end, and the drain electrode of the first MOS tube is connected with the first input end of the reverse protection circuit;
the voltage reduction circuit is used for controlling the opening or closing of the first MOS tube according to the voltage of the first output end of the overvoltage protection circuit.
Optionally, the voltage dropping circuit includes a first resistor and a second resistor; wherein,
the first end of the first resistor is connected with the preset first voltage input end, the second end of the first resistor is connected with the first output end of the overvoltage protection circuit, the first end of the second resistor and the grid electrode of the first MOS tube respectively, and the second end of the second resistor is connected with the preset second voltage input end.
Optionally, the switch circuit further includes a third resistor;
the first end of the third resistor is connected with the grid electrode of the first MOS tube, and the second end of the third resistor is connected with the second end of the first resistor.
Optionally, the switch circuit further comprises a capacitor;
the first end of the capacitor is connected with the first end of the first resistor, and the second end of the capacitor is connected with the second end of the first resistor.
Optionally, the overvoltage protection circuit includes a detection circuit and a triode; the input end of the detection circuit is connected with the preset first voltage input end, the first output end of the detection circuit is connected with the base electrode of the triode, the second output end of the detection circuit is connected with the preset second voltage input end, the emitting electrode of the triode is connected with the preset first voltage input end, and the collector electrode of the triode is connected with the second end of the first resistor;
the detection circuit is used for collecting a first voltage of the preset first voltage input end and controlling the triode to be opened or closed according to the first voltage.
Optionally, the detection circuit includes a fourth resistor, a fifth resistor, a sixth resistor, and a zener diode; wherein,
the first end of the fourth resistor is connected with the preset first voltage input end, the second end of the fourth resistor is respectively connected with the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected with the base electrode of the triode, the second end of the sixth resistor is connected with the cathode of the voltage stabilizing diode, and the anode of the voltage stabilizing diode is connected with the preset second voltage input end.
Optionally, the reverse protection circuit includes a seventh resistor, an eighth resistor, and a second MOS transistor; wherein,
the first end of the seventh resistor is connected with the preset second voltage input end, the second end of the seventh resistor is respectively connected with the first end of the eighth resistor and the grid electrode of the second MOS tube, the second end of the eighth resistor is connected with the preset voltage output end, the source electrode of the second MOS tube is connected with the preset voltage output end, and the drain electrode of the second MOS tube is connected with the first output end of the switch circuit.
Optionally, the reverse protection circuit further includes a diode;
and the anode of the diode is respectively connected with the second output end of the overvoltage protection circuit and the second output end of the switch circuit, and the cathode of the diode is connected with the preset second voltage input end.
To achieve the above object, the present invention further provides a power input device, which includes the voltage protection circuit as described above.
The utility model discloses in, voltage protection circuit includes: overvoltage protection circuit, switching circuit and reverse protection circuit. The switching circuit is used for controlling the loop between the preset first voltage input end and the reverse protection circuit to be switched on or switched off; the overvoltage protection circuit is used for detecting a first voltage of the preset first voltage input end and controlling the switching circuit to be switched off when the first voltage is greater than a first preset threshold value; the reverse protection circuit is used for detecting a second voltage of the preset second voltage input end and controlling the circuit between the switch circuit and the preset voltage output end to be switched on or switched off according to the second voltage. The utility model realizes the overvoltage protection of the input voltage through the overvoltage protection circuit, and cuts off the input when the input voltage is too high; meanwhile, reverse voltage protection is realized through the reverse protection circuit, and when the voltage is reversely connected, the input is cut off, so that the safety of the back-end circuit is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a schematic circuit diagram of a first embodiment of a voltage protection circuit according to the present invention;
fig. 2 is a schematic circuit diagram of a second embodiment of the voltage protection circuit according to the present invention;
fig. 3 is a schematic circuit diagram of a third embodiment of the voltage protection circuit according to the present invention;
FIG. 4 is a schematic diagram of a diode parallel configuration of an exemplary reverse protection circuit;
FIG. 5 is a schematic diagram of a diode series configuration of an exemplary reverse protection circuit;
FIG. 6 is a diagram showing simulation results of the over-voltage protection of the voltage protection circuit according to the present embodiment;
fig. 7 is a diagram illustrating a simulation result of reverse protection of the voltage protection circuit according to the present embodiment.
The reference numbers illustrate:
| 100 | overvoltage protection circuit | Q1～Q2 | First to |
|
| 1001 | Detection circuit | R1～R8 | First to |
|
| 200 | Switching circuit | C | Capacitor with a |
|
| 2001 | Voltage reduction circuit | | Triode transistor | |
| 300 | Reverse protection circuit | ZD | Voltage stabilizing diode | |
| VIN1～2 | Presetting first-second voltage input ends | D | Diode with a high-voltage source | |
| VOUT | Preset voltage output terminal |
The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, it should be considered that the combination of the technical solutions does not exist, and is not within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic circuit structure diagram of a first embodiment of the voltage protection circuit according to the present invention.
As shown in fig. 1, in the present embodiment, the voltage protection circuit includes: an overvoltage protection circuit 100, a switch circuit 200 and a reverse protection circuit 300; the input end of the overvoltage protection circuit 100 is connected to a preset first voltage input end, the first output end of the overvoltage protection circuit 100 is connected to the control end of the switch circuit 200, the second output end of the overvoltage protection circuit 100 is connected to a preset second voltage input end, the input end of the switch circuit 200 is connected to the preset first voltage input end, the first output end of the switch circuit 200 is connected to the first input end of the reverse protection circuit 300, the second output end of the switch circuit 200 is connected to the preset second voltage input end, the second input end of the reverse protection circuit 300 is connected to the preset second voltage input end, and the output end of the reverse protection circuit 300 is connected to the preset voltage output end.
It should be noted that the preset first voltage input terminal and the preset second voltage input terminal may be used for power input. For example, the first voltage input terminal is connected to the positive terminal of the power supply, and the second voltage input terminal is connected to the negative terminal of the power supply or ground. The preset voltage output end can be used for being connected with an electric circuit, and the voltage protection circuit can provide required working voltage for the electric circuit.
The switch circuit 200 is configured to control a loop between the preset first voltage input terminal and the reverse protection circuit to be turned on or off.
It is understood that the switch circuit 200 has two states of being closed and open, and when the switch circuit 200 is closed, the voltage can be transmitted from the preset first voltage input terminal to the input terminal of the reverse protection circuit; if disconnected, it cannot be transmitted. The switching circuit 200 is a first-stage control of the input power supply, and can quickly cut off the input when the voltage is abnormal.
In a specific implementation, the switching circuit 200 may employ a switching device such as a MOS transistor, a triode, or a relay. The specific circuit structure may be set as required, and this embodiment is not limited thereto.
The overvoltage protection circuit 100 is configured to detect a first voltage at a preset first voltage input end, and control the switch circuit 200 to turn off when the first voltage is greater than a first preset threshold.
It is understood that overvoltage protection refers to a protection mode that disconnects the power supply or reduces the voltage of the controlled device when the protected line voltage exceeds a predetermined maximum value. In this embodiment, it is preset that the first voltage input terminal is connected to the positive electrode of the power supply, and the first voltage is an input voltage. And when the first voltage is greater than a first preset threshold value, performing overvoltage protection by adopting a power-off mode. The specific number of the first preset threshold may be set according to the requirement, which is not limited in this embodiment.
The reverse protection circuit 300 is configured to detect a second voltage at the preset second voltage input end, and control a loop between the switch circuit 200 and the preset voltage output end to be switched on or switched off according to the second voltage.
It is understood that reverse protection refers to a protection mode for disconnecting the power supply when the positive electrode and the negative electrode of the input power supply are reversely connected. In this embodiment, the normal power connection state is: the preset first voltage input end is connected with the positive pole of the power supply, and the preset second voltage input end is connected with the negative pole of the power supply or grounded. When the second voltage input end is connected with the positive pole of the power supply and the first voltage input end is connected with the negative pole of the power supply or grounded, the input is reversely connected.
It should be noted that, it is usually preset that the second voltage input terminal is connected to the negative electrode of the power supply or ground, and the second voltage is lower. When the second voltage rises, the reverse protection circuit 300 may determine that the reverse input is input, and at this time, a loop between the switching circuit 200 and the preset voltage output terminal is cut off to cut off the power input. In a normal connection state, the switch circuit 200 is connected to the preset voltage output terminal.
In a first embodiment, the voltage protection circuit includes an overvoltage protection circuit, a switching circuit, and a reverse protection circuit. The switching circuit is used for controlling the loop between the preset first voltage input end and the reverse protection circuit to be switched on or switched off; the overvoltage protection circuit is used for detecting a first voltage of the preset first voltage input end and controlling the switching circuit to be switched off when the first voltage is greater than a first preset threshold value; the reverse protection circuit is used for detecting a second voltage of the preset second voltage input end and controlling the circuit between the switch circuit and the preset voltage output end to be switched on or switched off according to the second voltage. The utility model realizes the overvoltage protection of the input voltage through the overvoltage protection circuit, and cuts off the input when the input voltage is too high; meanwhile, reverse voltage protection is realized through the reverse protection circuit, and when the voltage is reversely connected, the input is cut off, so that the safety of the back-end circuit is ensured.
Referring to fig. 2, fig. 2 is a schematic circuit structure diagram of a second embodiment of the voltage protection circuit according to the present invention. Based on above-mentioned first embodiment, provide the utility model discloses voltage protection circuit second embodiment.
In the second embodiment, the switching circuit 200 includes a first MOS transistor Q1 and a step-down circuit 2001; a first input end of the voltage-reducing circuit 2001 is connected with a preset first voltage input end, a second input end of the voltage-reducing circuit 2001 is connected with a first output end of the overvoltage protection circuit 100, a first output end of the voltage-reducing circuit 2001 is connected with a grid electrode of the first MOS transistor Q1, and a second output end of the voltage-reducing circuit 2001 is connected with a preset second voltage input end; the source of the first MOS transistor Q1 is connected to a preset first voltage input terminal, and the drain of the first MOS transistor Q1 is connected to a first input terminal of the reverse protection circuit 300. The voltage reducing circuit 2001 is used for controlling the opening or closing of the first MOS transistor Q1 according to the voltage of the first output end of the overvoltage protection circuit.
It should be noted that in this embodiment, a MOS transistor is used as the switching device, and specifically, the first MOS transistor Q1 may be a P-channel MOS transistor. The voltage dropping circuit 2001 may convert a first voltage preset at the first voltage input terminal and apply the converted first voltage to the gate of the first MOS transistor Q1.
It should be noted that the voltage reducing circuit 2001 determines the conversion form of the first voltage according to the voltage of the first output terminal of the overvoltage protection circuit. Under normal conditions, the voltage-reducing circuit 2001 reduces the first voltage and then applies the reduced voltage to the gate of the first MOS transistor Q1, so that the first MOS transistor Q1 is turned on, and normal power input is realized. In an abnormal situation, the voltage-reducing circuit 2001 directly applies the first voltage to the gate of the first MOS transistor Q1, thereby turning off the first MOS transistor Q1 to cut off the power input.
In a specific implementation, the voltage-reducing circuit 2001 includes a first resistor R1 and a second resistor R2; a first end of the first resistor R1 is connected to a preset first voltage input end, a second end of the first resistor R1 is connected to a first output end of the overvoltage protection circuit 100, a first end of the second resistor R1 and a gate of the first MOS transistor Q1, and a second end of the second resistor R2 is connected to a preset second voltage input end.
It can be understood that the first voltage of the preset first voltage input terminal is divided by the first resistor R1 and the second resistor R2, so that the voltage applied to the gate of the first MOS transistor Q1 is smaller than the source voltage of the first MOS transistor Q1. Meanwhile, the overvoltage protection circuit 100 can adjust the connection state of the first resistor R1 to adjust the voltage division state, so as to control the voltage relationship between the gate and the source of the first MOS transistor Q1.
In a specific implementation, the switching circuit 200 further includes a third resistor R3; a first end of the third resistor R3 is connected to the gate of the first MOS transistor Q1, and a second end of the third resistor R3 is connected to the second end of the first resistor R1.
It is understood that the parasitic inductance of the gate loop is unavoidable, and in order to avoid the oscillation of the gate loop, the third resistor R3 is used to quickly damp the gate oscillation in the present embodiment, so as to eliminate the gate oscillation.
In particular implementation, the switching circuit 200 further includes a capacitor C; a first terminal of the capacitor C is connected to a first terminal of the first resistor R1, and a second terminal of the capacitor C is connected to a second terminal of the first resistor R1.
It can be understood that, in order to ensure that the voltage difference between the gate and the source of the first MOS transistor Q1 is stable, the voltage difference is maintained by the capacitor C in the present embodiment, so that the first MOS transistor has a stable on state.
In addition, in order to better implement overvoltage protection, in the present embodiment, the overvoltage protection circuit 100 includes a detection circuit 1001 and a transistor T; the input end of the detection circuit 1001 is connected with a preset first voltage input end, the first output end of the detection circuit 1001 is connected with the base electrode of the triode T, the second output end of the detection circuit 1001 is connected with a preset second voltage input end, the emitting electrode of the triode T is connected with the preset first voltage input end, and the collector electrode of the triode T is connected with the second end of the first resistor R1. The detection circuit 1001 is configured to collect a first voltage at a preset first voltage input end, and control the on or off of the triode T according to the first voltage.
It is understood that the transistor T is connected in parallel with the first resistor R1, and when the transistor T is turned off, the first resistor R1 and the second resistor R2 divide the first voltage at the preset first voltage input terminal, so that the voltage applied to the gate of the first MOS transistor Q1 is less than the source voltage of the first MOS transistor Q1. When the transistor T is turned on, the first resistor R1 is shorted, and the first voltage is directly applied to the gate and the source of the first MOS transistor Q1, so that the first MOS transistor Q1 is turned off.
It should be noted that the detection circuit 1001 may control the transistor T to be turned on when the first voltage is greater than a preset first preset threshold. In a specific implementation, the detection circuit 1001 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a zener diode ZD; the first end of the fourth resistor R4 is connected with a preset first voltage input end, the second end of the fourth resistor R4 is respectively connected with the first end of the fifth resistor R5 and the first end of the sixth resistor R6, the second end of the fifth resistor R5 is connected with the base electrode of the triode T, the second end of the sixth resistor R6 is connected with the cathode of the zener diode ZD, and the anode of the zener diode ZD is connected with a preset second voltage input end.
It can be understood that when the first voltage is not sufficient to break down the zener diode ZD, the base of the triode T has no current and cannot conduct. If the first voltage is enough to break down the zener diode ZD, that is, the input voltage is too high, the triode T is turned on, the first MOS transistor Q1 is turned off, and the current returns to the preset second voltage input terminal, thereby implementing overvoltage protection.
In a second embodiment, the switch circuit includes a first MOS transistor and a voltage reduction circuit, and the voltage reduction circuit can adjust a voltage difference between a gate and a source of the first MOS transistor, so as to control on/off of the first MOS transistor. Meanwhile, the overvoltage protection circuit adjusts the voltage reduction state of the voltage reduction circuit according to the first voltage of the first preset voltage input end so as to change the voltage difference between the grid electrode and the source electrode of the first MOS tube and control the opening or closing of the first MOS tube, overvoltage protection is achieved, and the safety and the reliability of the circuit are improved.
Referring to fig. 3, fig. 3 is a schematic circuit structure diagram of a third embodiment of the voltage protection circuit according to the present invention. Based on the first and second embodiments, the third embodiment of the voltage protection circuit of the present invention is provided. The present embodiment is explained based on the second embodiment.
In the third embodiment, the reverse protection circuit 300 includes a seventh resistor R7, an eighth resistor R8, and a second MOS transistor Q2; a first end of the seventh resistor R7 is connected to the preset second voltage input terminal, a second end of the seventh resistor R7 is connected to the first end of the eighth resistor R8 and the gate of the second MOS transistor Q2, a second end of the eighth resistor R8 is connected to the preset voltage output terminal, a source of the second MOS transistor Q2 is connected to the preset voltage output terminal, and a drain of the second MOS transistor Q2 is connected to the first output terminal of the switching circuit 200.
It should be noted that the second MOS transistor Q2 may be a P-channel MOS transistor, and under a normal voltage input condition, a current flows to the preset voltage output terminal through a parasitic diode of the second MOS transistor Q2; then, the second MOS transistor Q2 is turned on. When the input power supply is reversely connected, the gate voltage of the second MOS transistor Q2 is greater than the source voltage, and the second MOS transistor Q2 is disconnected, so that a loop cannot be formed, and reverse protection is realized. At this time, although the preset voltage output end is at a high level, the two ends of the back-end device are always at a high level state, and the back-end device cannot work without current generation, so that a reverse protection effect can be achieved.
Further, in order to make the reverse protection more stable, in the present embodiment, the reverse protection circuit 300 further includes a diode D; the anode of the diode D is connected to the second output terminal of the overvoltage protection circuit 100 and the second output terminal of the switch circuit 200, and the cathode of the diode D is connected to the preset second voltage input terminal.
It can be understood that when the input power is reversely connected, no current flows through the overvoltage protection circuit 100 and the switch circuit 200 due to the reverse connection of the diode, thereby further improving the reverse protection capability.
It should be noted that, in general, the conventional reverse protection uses diodes, specifically, there are two connection modes, i.e., parallel connection and series connection. Referring to fig. 4 and 5, fig. 4 is a schematic diagram of a diode parallel structure of an exemplary reverse protection circuit; fig. 5 is a schematic diagram of an exemplary diode series reverse protection circuit.
The actual capacitor in the parallel connection mode of the diodes still has negative pressure, and although the negative pressure is small, the aluminum electrolytic capacitor still can be damaged, and the performance of the aluminum electrolytic capacitor can be reduced. And if the adapter does not have the overcurrent protection, have great temperature rise, have risks such as electric capacity explosion. Even when the reverse voltage is too large to damage the diode, the circuit is still in a reverse voltage state, and the risk is high.
In the embodiment, a voltage protection circuit is formed by adopting devices such as two-stage MOS tube switches and diodes, the internal resistance of the MOS tube is very small, and the problems of overlarge voltage drop and power consumption existing in the conventional scheme of preventing reverse connection of a diode power supply are solved.
Referring to fig. 6 and 7, fig. 6 is a diagram illustrating an overvoltage protection simulation result of the voltage protection circuit according to the embodiment; fig. 7 is a diagram illustrating a simulation result of reverse protection of the voltage protection circuit according to the present embodiment. It can be known from the figure that when the input voltage reaches the overvoltage protection point, the MOS transistor clamps the output voltage value, and the overvoltage protection function is realized. When the input voltage is reversed, although the output is high level, the two ends of the back-end device are always in a high level state, and the back-end device cannot work without current generation, so that the back-end device can play a role in reverse protection.
In the third embodiment, a voltage protection circuit is formed by adopting two stages of MOS transistor switches, diodes and other devices, and the two stages of MOS transistor switches can realize overvoltage protection and reverse protection functions of the circuit, and the problems of voltage drop and excessive power consumption do not exist. This embodiment is realizing overvoltage protection function and is adding circuit reverse protection function simultaneously newly, promotes circuit safe and reliable performance.
To achieve the above object, the present invention further provides a power input device, which includes the voltage protection circuit as described above. Since the power input device adopts all the technical solutions of all the embodiments, at least all the beneficial effects brought by the technical solutions of the embodiments are achieved, and no further description is given here.
The above is only the preferred embodiment of the present invention, and not the scope of the present invention, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings or the direct or indirect application in other related technical fields are included in the patent protection scope of the present invention.
Claims (10)
1. A voltage protection circuit, characterized in that the voltage protection circuit comprises: the overvoltage protection circuit, the switch circuit and the reverse protection circuit; the input end of the overvoltage protection circuit is connected with a preset first voltage input end, the first output end of the overvoltage protection circuit is connected with the control end of the switch circuit, the second output end of the overvoltage protection circuit is connected with a preset second voltage input end, the input end of the switch circuit is connected with the preset first voltage input end, the first output end of the switch circuit is connected with the first input end of the reverse protection circuit, the second output end of the switch circuit is connected with the preset second voltage input end, the second input end of the reverse protection circuit is connected with the preset second voltage input end, and the output end of the reverse protection circuit is connected with the preset voltage output end;
the switch circuit is used for controlling the loop between the preset first voltage input end and the reverse protection circuit to be switched on or switched off;
the overvoltage protection circuit is used for detecting a first voltage of the preset first voltage input end and controlling the switching circuit to be switched off when the first voltage is greater than a first preset threshold value;
the reverse protection circuit is used for detecting a second voltage of the preset second voltage input end and controlling the circuit between the switch circuit and the preset voltage output end to be switched on or switched off according to the second voltage.
2. The voltage protection circuit of claim 1, wherein the switching circuit comprises a first MOS transistor and a voltage dropping circuit; a first input end of the voltage reduction circuit is connected with the preset first voltage input end, a second input end of the voltage reduction circuit is connected with a first output end of the overvoltage protection circuit, a first output end of the voltage reduction circuit is connected with a grid electrode of the first MOS tube, and a second output end of the voltage reduction circuit is connected with the preset second voltage input end; the source electrode of the first MOS tube is connected with the preset first voltage input end, and the drain electrode of the first MOS tube is connected with the first input end of the reverse protection circuit;
the voltage reduction circuit is used for controlling the opening or closing of the first MOS tube according to the voltage of the first output end of the overvoltage protection circuit.
3. The voltage protection circuit of claim 2, wherein the voltage dropping circuit comprises a first resistor and a second resistor; wherein,
the first end of the first resistor is connected with the preset first voltage input end, the second end of the first resistor is connected with the first output end of the overvoltage protection circuit, the first end of the second resistor and the grid electrode of the first MOS tube respectively, and the second end of the second resistor is connected with the preset second voltage input end.
4. The voltage protection circuit of claim 3, wherein the switching circuit further comprises a third resistor;
the first end of the third resistor is connected with the grid electrode of the first MOS tube, and the second end of the third resistor is connected with the second end of the first resistor.
5. The voltage protection circuit of claim 3, wherein the switching circuit further comprises a capacitor;
the first end of the capacitor is connected with the first end of the first resistor, and the second end of the capacitor is connected with the second end of the first resistor.
6. The voltage protection circuit of claim 3, wherein the over-voltage protection circuit comprises a detection circuit and a transistor; the input end of the detection circuit is connected with the preset first voltage input end, the first output end of the detection circuit is connected with the base electrode of the triode, the second output end of the detection circuit is connected with the preset second voltage input end, the emitting electrode of the triode is connected with the preset first voltage input end, and the collector electrode of the triode is connected with the second end of the first resistor;
the detection circuit is used for collecting a first voltage of the preset first voltage input end and controlling the triode to be opened or closed according to the first voltage.
7. The voltage protection circuit of claim 6, wherein the detection circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, and a zener diode; wherein,
the first end of the fourth resistor is connected with the preset first voltage input end, the second end of the fourth resistor is respectively connected with the first end of the fifth resistor and the first end of the sixth resistor, the second end of the fifth resistor is connected with the base electrode of the triode, the second end of the sixth resistor is connected with the cathode of the voltage stabilizing diode, and the anode of the voltage stabilizing diode is connected with the preset second voltage input end.
8. The voltage protection circuit of any one of claims 1-7, wherein the reverse protection circuit comprises a seventh resistor, an eighth resistor, and a second MOS transistor; wherein,
the first end of the seventh resistor is connected with the preset second voltage input end, the second end of the seventh resistor is respectively connected with the first end of the eighth resistor and the grid electrode of the second MOS tube, the second end of the eighth resistor is connected with the preset voltage output end, the source electrode of the second MOS tube is connected with the preset voltage output end, and the drain electrode of the second MOS tube is connected with the first output end of the switch circuit.
9. The voltage protection circuit of claim 8, wherein the reverse protection circuit further comprises a diode;
and the anode of the diode is respectively connected with the second output end of the overvoltage protection circuit and the second output end of the switch circuit, and the cathode of the diode is connected with the preset second voltage input end.
10. A power input device, characterized in that it comprises a voltage protection circuit as claimed in any one of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023196558.1U CN214045014U (en) | 2020-12-24 | 2020-12-24 | Voltage protection circuit and power input device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023196558.1U CN214045014U (en) | 2020-12-24 | 2020-12-24 | Voltage protection circuit and power input device |
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| CN214045014U true CN214045014U (en) | 2021-08-24 |
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| CN202023196558.1U Active CN214045014U (en) | 2020-12-24 | 2020-12-24 | Voltage protection circuit and power input device |
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