CN211351687U - Overvoltage protection circuit, charging equipment and electronic equipment - Google Patents
Overvoltage protection circuit, charging equipment and electronic equipment Download PDFInfo
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- CN211351687U CN211351687U CN202020196853.8U CN202020196853U CN211351687U CN 211351687 U CN211351687 U CN 211351687U CN 202020196853 U CN202020196853 U CN 202020196853U CN 211351687 U CN211351687 U CN 211351687U
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Abstract
An overvoltage protection circuit, charging equipment and electronic equipment comprise a voltage detection circuit, wherein the voltage detection circuit comprises a reference source circuit, a first voltage division circuit and a first voltage division common end, and the reference source circuit outputs reference voltage and is connected with the first voltage division common end; the switch protection circuit comprises a triode, an MOS (metal oxide semiconductor) tube, a second voltage division circuit and a second voltage division common end, wherein the base electrode of the triode is connected with the reference source circuit and the second voltage division common end; the MOS tube is respectively connected with the second voltage division common terminal and the voltage output terminal; when the voltage of the first voltage division common terminal is smaller than the reference voltage, the reference source circuit is cut off, the triode is cut off, and the MOS tube is conducted to realize power supply; when the voltage of the first voltage division common terminal is larger than the reference voltage, the reference source circuit is conducted, the triode is conducted, the MOS tube is cut off, and the voltage output terminal does not have power supply. The utility model provides an overvoltage crowbar effectively solves the damage to electronic equipment when preventing input voltage too high, the especially field of charging that is applicable to the intelligence lock.
Description
Technical Field
The utility model relates to an electronic circuit field especially relates to an overvoltage protection technical field that intelligence lock charges.
Background
At present, a common overvoltage protection circuit generally adopts a voltage stabilizing diode as overvoltage sampling detection, the voltage precision is not high, and the voltage stabilizing diode can meet the application requirement only by being replaced when different voltages are required. For some electronic devices requiring precise voltage protection, there is a certain risk, such as smart locks commonly used in the market.
The intelligent lock mostly uses dry battery or lithium cell as the power supply and supplies power, if do not change the battery in time or charge after exhausting the electric quantity, will cause the condition that can't open the door. The current intelligent lock solves the problem by using a USB interface to supply power by a mobile power supply in an emergency mode, or using a standard 9V square battery in an emergency mode, or using a mechanical key to unlock the lock in an emergency mode. When using the USB interface to connect external power source, because the unstability of external power source voltage or USB interface receive outside when maliciously attacking, cause the inside components and parts of intelligent lock to damage easily, lead to the unable use of intelligent lock.
Disclosure of Invention
The utility model discloses shortcoming to among the prior art provides an overvoltage crowbar, effectively solves to prevent when input voltage is too high to electronic equipment's damage, the especially field of charging that is applicable to the intelligence lock.
In order to solve the technical problem, the utility model discloses a following technical scheme can solve:
an overvoltage protection circuit comprising: the voltage input end is used for receiving externally input power supply voltage; the voltage output end is used for outputting working voltage;
the voltage detection circuit comprises a reference source circuit, a first voltage division circuit and a first voltage division common terminal, wherein the reference source circuit outputs a reference voltage and is connected with the first voltage division common terminal;
the switch protection circuit comprises a triode, an MOS (metal oxide semiconductor) tube, a second voltage division circuit and a second voltage division common end, wherein the base electrode of the triode is connected with the reference source circuit and the second voltage division common end; the MOS tube is respectively connected with the second voltage division common terminal and the voltage output terminal;
when the voltage of the first voltage division common terminal is smaller than the reference voltage, the reference source circuit is cut off, the triode is cut off, and the MOS tube is conducted to realize power supply; when the voltage of the first voltage division common terminal is larger than the reference voltage, the reference source circuit is conducted, the triode is conducted, the MOS tube is cut off, and the voltage output terminal does not have power supply.
Optionally, the reference source circuit includes a reference source IC1 and a resistor R1, the cathode of the reference source IC1 is connected to the positive electrode of the power supply through the resistor R1, the anode is connected to GND, and the reference terminal is connected to the first voltage-dividing common terminal.
Optionally, the switch protection circuit includes a PNP triode, a PMOS transistor, a second voltage division circuit, and a second voltage division common terminal;
the B pole of the triode is connected with the cathode of the reference source, the E pole of the triode is connected with the anode of the power supply, and the C pole of the triode is connected with the second voltage division common end;
and the S pole of the PMOS tube is connected to the positive pole of the power supply, the D pole of the PMOS tube is connected to the voltage output end, and the G pole of the PMOS tube is connected to the second voltage division common end.
Optionally, the B pole of the transistor is connected to the resistor R2, and the other end of the resistor R2 is connected between the resistor R1 and the cathode of the reference source.
Optionally, the first voltage dividing circuit includes voltage dividing resistors R5 and R6, one end of the voltage dividing resistor R5 is connected to the positive electrode of the power supply, the other end of the voltage dividing resistor R5 is connected to the first voltage dividing common terminal, one end of the voltage dividing resistor R6 is connected to GND, and the other end of the voltage dividing resistor R6 is connected to the first voltage dividing common terminal.
Optionally, the second voltage-dividing resistor includes voltage-dividing resistors R3 and R4, one end of the voltage-dividing resistor R3 is connected to the positive electrode of the power supply, the other end of the voltage-dividing resistor R3 is connected to the second voltage-dividing common terminal, one end of the voltage-dividing resistor R4 is connected to GND, and the other end of the voltage-dividing resistor R4 is connected to the second voltage-dividing common.
Optionally, the voltage output end is further connected with a capacitor, and the other end of the capacitor is connected with GND.
Optionally, the first voltage division common end is further connected with a capacitor, and the other end of the capacitor is electrically connected with GND.
The utility model also provides a charging device for charging electronic equipment, independent of the electronic equipment, comprising the overvoltage protection circuit, wherein the voltage input end is used for receiving the voltage input from the outside; the voltage output end is connected with the electronic equipment and used for outputting the working voltage to the electronic equipment for use.
The utility model also provides an electronic device, the overvoltage protection circuit is located inside the electronic device and is used for providing stable working voltage for the electronic device, and the voltage input end is used for receiving the voltage input from the outside of the electronic device; and the voltage output end is used for outputting the working voltage to the electronic equipment for use.
The utility model has the advantages that:
1. the utility model discloses a benchmark source IC1 detects as the excessive pressure sampling, and the voltage detection precision is high, and voltage requirement to the difference only needs adjustment R5, and R6's resistance can accord with the application requirement.
2. The utility model discloses a reference source realizes detecting to input mains voltage to the break-make of control PMOS pipe solves the probably too high problem of input voltage of present USB interface. Meanwhile, the technical scheme does not need the MCU to participate in control, and can normally detect and control the PMOS tube to work when the battery is completely dead.
3. The utility model discloses can effectively prevent the damage to the intelligence lock when input voltage is too high to protection circuit also can normally work when the battery thoroughly does not have the electricity, thereby guarantees intelligent lock normal use.
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 these drawings without inventive exercise.
Fig. 1 is a circuit diagram of an overvoltage protection circuit.
Detailed Description
The present invention will be described in further detail with reference to the following examples, which are illustrative of the present invention and are not intended to limit the present invention.
In this embodiment, the electronic device is an intelligent lock, which may of course be used for other devices, as shown in fig. 1: an overvoltage protection circuit is provided, wherein R1, R2, R3, R4, R5 and R6 are common resistors, C1 and C2 are filter capacitors, IC1 is a reference source, Q1 is a PNP triode, Q2 is a PMOS, Vref is an input voltage sampling point, the voltage division value of power supply voltage input by a voltage input end is R5 and R6, and a connection voltage output end is connected with intelligent lock power supply voltage VBAT.
The overvoltage protection circuit specifically includes: the voltage input end is used for receiving externally input power supply voltage; in this embodiment, a USB input terminal is adopted;
the voltage output end is used for outputting working voltage; the voltage output end is connected with an intelligent lock power supply;
the voltage detection circuit comprises a reference source circuit, a first voltage division circuit and a first voltage division common terminal Vref, wherein the reference source circuit outputs a reference voltage and is connected with the first voltage division common terminal Vref;
the switch protection circuit comprises a triode, an MOS (metal oxide semiconductor) tube, a second voltage division circuit and a second voltage division common end, wherein the base electrode of the triode is connected with the reference source circuit and the second voltage division common end; the MOS tube is respectively connected with the second voltage division common terminal and the voltage output terminal;
the reference source circuit comprises a reference source IC1 and a resistor R1, and the reference source IC1 adopts a TL431 chip in the embodiment. The cathode of the reference source IC1 is connected to the positive power supply via a resistor R1, the anode is connected to GND, and the reference terminal is connected to the first voltage-dividing common terminal Vref.
The switch protection circuit comprises a PNP triode, a PMOS (P-channel metal oxide semiconductor) tube, a second voltage division circuit and a second voltage division common end;
the B pole of the PNP triode is connected with the cathode of the reference source, the E pole of the PNP triode is connected with the anode of the power supply, and the C pole of the PNP triode is connected with the second voltage division common end; and the S pole of the PMOS tube is connected to the positive pole of the power supply, the D pole of the PMOS tube is connected to the voltage output end, and the G pole of the PMOS tube is connected to the second voltage division common end. The B pole of the triode is connected with the resistor R2, and the other end of the resistor R2 is connected between the resistor R1 and the cathode of the reference source.
The first voltage division circuit comprises voltage division resistors R5 and R6, one end of the voltage division resistor R5 is connected to the positive electrode of a power supply, the other end of the voltage division resistor R5 is connected with a first voltage division common end Vref, one end of the voltage division resistor R6 is connected with GND, and the other end of the voltage division resistor R6 is connected with the first voltage division common end Vref. The second voltage-dividing resistor comprises voltage-dividing resistors R3 and R4, one end of the voltage-dividing resistor R3 is connected to the anode of the power supply, the other end of the voltage-dividing resistor R3 is connected to the second voltage-dividing common end, one end of the voltage-dividing resistor R4 is connected to GND, and the other end of the voltage-dividing resistor R4 is connected to the second voltage-dividing common.
The voltage output end is further connected with a filter capacitor C1, and the other end of the capacitor C1 is connected with GND. The first voltage division common end is further connected with a filter capacitor C2, and the other end of the capacitor C2 is electrically connected with GND.
The operation principle of the embodiment is as follows:
normally, when the Vref value is smaller than the reference voltage of IC1, IC1 is not broken down and is in a cut-off state, so the B pole of PNP triode Q1 is pulled up to the input power voltage through resistors R1 and R2, Vbe is 0V, triode Q1 is in a cut-off state, Q2 satisfies Vth turn-on voltage, Q2 is turned on, and the power is normally supplied to the rear-stage smart lock.
The G-pole voltage of the PMOS tube Q2 is R3, R4 divides the voltage value of the input voltage, and when the Vth starting voltage is met, Q2 is conducted, and the emergency power supply can be normally provided for the intelligent lock power circuit. When the Vref value is larger than the reference voltage of the IC1, the IC1 is conducted, when Vbe is larger than the threshold value of Q1, Q1 is conducted, so that the equipotential of the S pole and the D pole of Q2 does not meet the Vth starting voltage, and Q2 is not conducted, thereby protecting the rear-stage intelligent lock circuit.
Example 2:
the utility model also provides a charging device, which is used for charging the electronic device and is independent of the electronic device, and the internal structure comprises the overvoltage protection circuit of the embodiment 1, and comprises a voltage input end used for receiving the voltage input from the outside; and the voltage output end is connected with the electronic equipment and used for outputting the working voltage to the electronic equipment for use. In this embodiment, the charging device can charge various electronic devices, has an overvoltage protection function, and can realize different voltage threshold protection by adjusting the resistance value of the divider resistor to adjust the threshold.
Example 3:
the utility model also provides an electronic device, the overvoltage protection circuit of embodiment 1 is located inside the electronic device, and is used for providing stable working voltage for the electronic device, and the voltage input end is used for receiving the voltage input from the outside of the electronic device; and the voltage output end is used for outputting the working voltage to the electronic equipment for use.
The electronic equipment can be an intelligent lock, the power supply part of the intelligent lock is provided with an overvoltage protection circuit, the threshold voltage needing to be protected is adjusted, and input of different emergency voltages can be achieved.
It should be noted that:
reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
While the preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the invention.
In addition, it should be noted that the specific embodiments described in the present specification may differ in the shape of the components, the names of the components, and the like. All equivalent or simple changes made according to the structure, characteristics and principle of the utility model are included in the protection scope of the utility model. Various modifications, additions and substitutions may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.
Claims (10)
1. An overvoltage protection circuit comprises a voltage input end, a voltage output end and a voltage output end, wherein the voltage input end is used for receiving an externally input power supply voltage; the voltage output end is used for outputting working voltage; it is characterized by also comprising:
the voltage detection circuit comprises a reference source circuit, a first voltage division circuit and a first voltage division common terminal, wherein the reference source circuit outputs a reference voltage and is connected with the first voltage division common terminal;
the switch protection circuit comprises a triode, an MOS (metal oxide semiconductor) tube, a second voltage division circuit and a second voltage division common end, wherein the base electrode of the triode is connected with the reference source circuit and the second voltage division common end; the MOS tube is respectively connected with the second voltage division common terminal and the voltage output terminal;
when the voltage of the first voltage division common terminal is smaller than the reference voltage, the reference source circuit is cut off, the triode is cut off, and the MOS tube is conducted to realize power supply; when the voltage of the first voltage division common terminal is larger than the reference voltage, the reference source circuit is conducted, the triode is conducted, the MOS tube is cut off, and the voltage output terminal does not have power supply.
2. The overvoltage protection circuit of claim 1, wherein the reference source circuit comprises a reference source IC1 and a resistor R1, the cathode of the reference source IC1 is connected to the positive terminal of the power supply through the resistor R1, the anode is connected to GND, and the reference terminal is connected to the first voltage-dividing common terminal.
3. The overvoltage protection circuit of claim 2, wherein the switch protection circuit comprises a PNP transistor, a PMOS transistor, and a second voltage divider circuit and a second voltage divider common;
the B pole of the triode is connected with the cathode of the reference source, the E pole of the triode is connected with the anode of the power supply, and the C pole of the triode is connected with the second voltage division common end;
and the S pole of the PMOS tube is connected to the positive pole of the power supply, the D pole of the PMOS tube is connected to the voltage output end, and the G pole of the PMOS tube is connected to the second voltage division common end.
4. The overvoltage protection circuit of claim 3, wherein the B-pole of the transistor is connected to a resistor R2, and the other end of the resistor R2 is connected between the resistor R1 and the cathode of the reference source.
5. The overvoltage protection circuit of claim 1 or 2, wherein the first voltage dividing circuit comprises voltage dividing resistors R5 and R6, one end of the voltage dividing resistor R5 is connected to the positive electrode of the power supply, the other end of the voltage dividing resistor R6 is connected to the first voltage dividing common terminal, and one end of the voltage dividing resistor R6 is connected to GND.
6. The overvoltage protection circuit of claim 2, wherein the second voltage divider resistor comprises voltage divider resistors R3 and R4, wherein one end of the voltage divider resistor R3 is connected to the positive terminal of the power supply, the other end of the voltage divider resistor R4 is connected to the second voltage divider common terminal, and one end of the voltage divider resistor R4 is connected to GND.
7. The overvoltage protection circuit of claim 1, wherein a capacitor is further connected to the voltage output terminal, and the other end of the capacitor is connected to GND.
8. The overvoltage protection circuit of claim 1, wherein a capacitor is further coupled to the first voltage division common, and another terminal of the capacitor is electrically coupled to GND.
9. A charging device for charging an electronic device, independent of the electronic device, comprising the overvoltage protection circuit of any one of claims 1 to 8,
the voltage input end is used for receiving an externally input voltage;
the voltage output end is connected with the electronic equipment and used for outputting the working voltage to the electronic equipment for use.
10. An electronic device, wherein the overvoltage protection circuit of any one of claims 1-8 is located inside the electronic device, and is configured to provide a stable operating voltage for the electronic device, and the voltage input terminal is configured to receive a voltage input from outside the electronic device; and the voltage output end is used for outputting the working voltage to the electronic equipment for use.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020196853.8U CN211351687U (en) | 2020-02-21 | 2020-02-21 | Overvoltage protection circuit, charging equipment and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020196853.8U CN211351687U (en) | 2020-02-21 | 2020-02-21 | Overvoltage protection circuit, charging equipment and electronic equipment |
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| Publication Number | Publication Date |
|---|---|
| CN211351687U true CN211351687U (en) | 2020-08-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020196853.8U Active CN211351687U (en) | 2020-02-21 | 2020-02-21 | Overvoltage protection circuit, charging equipment and electronic equipment |
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| Country | Link |
|---|---|
| CN (1) | CN211351687U (en) |
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- 2020-02-21 CN CN202020196853.8U patent/CN211351687U/en active Active
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