CN111181129A - Overvoltage protection circuit, charging equipment and electronic equipment - Google Patents
Overvoltage protection circuit, charging equipment and electronic equipment Download PDFInfo
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- CN111181129A CN111181129A CN202010108996.3A CN202010108996A CN111181129A CN 111181129 A CN111181129 A CN 111181129A CN 202010108996 A CN202010108996 A CN 202010108996A CN 111181129 A CN111181129 A CN 111181129A
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- voltage
- common terminal
- protection circuit
- voltage divider
- reference source
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Protection Of Static Devices (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
一种过压保护电路以及充电设备、电子设备，包括电压检测电路，包括基准源电路、第一分压电路和第一分压公共端，所述基准源电路输出基准电压，并连接所述第一分压公共端；开关保护电路，包括三极管、MOS管、第二分压电路和第二分压公共端，三极管基极连接基准源电路和第二分压公共端；MOS管分别连接第二分压公共端和电压输出端；当第一分压公共端电压小于基准电压时，基准源电路截止，三极管截止，MOS管导通实现电源供给；当第一分压公共端电压大于基准电压时，基准源电路导通，三极管导通，MOS管截止，电压输出端无电源供给。本发明提供了一种过压保护电路，有效解决防止输入电压过高时对电子设备的损坏，尤其的适用于智能锁的充电领域。
An overvoltage protection circuit, charging equipment, and electronic equipment, including a voltage detection circuit, including a reference source circuit, a first voltage divider circuit and a first voltage divider common terminal, the reference source circuit outputs a reference voltage, and is connected to the first voltage divider circuit. A voltage divider common terminal; the switch protection circuit includes a triode, a MOS tube, a second voltage divider circuit and a second voltage divider common terminal, the base of the triode is connected to the reference source circuit and the second voltage divider common terminal; the MOS tubes are respectively connected to the second voltage divider Voltage divider common terminal and voltage output terminal; when the first voltage divider common terminal voltage is lower than the reference voltage, the reference source circuit is turned off, the triode is turned off, and the MOS transistor is turned on to realize power supply; when the first voltage divider common terminal voltage is greater than the reference voltage , the reference source circuit is turned on, the triode is turned on, the MOS tube is turned off, and there is no power supply at the voltage output end. The invention provides an overvoltage protection circuit, which effectively solves the problem of preventing damage to electronic equipment when the input voltage is too high, and is especially suitable for the charging field of smart locks.
Description
Technical Field
The invention relates to the field of electronic circuits, in particular to the technical field of overvoltage protection for charging of an intelligent lock.
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
Aiming at the defects in the prior art, the invention provides an overvoltage protection circuit, which effectively prevents the electronic equipment from being damaged when the input voltage is overhigh, and is particularly suitable for the field of charging of intelligent locks.
In order to solve the technical problem, the invention is solved by the following technical scheme:
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 invention also provides a charging device which is used for charging the electronic device and is independent of the electronic device, and the charging device comprises 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 invention also provides an electronic device, wherein the overvoltage protection circuit is positioned in the electronic device and used for providing stable working voltage for the electronic device, and the voltage input end is used for receiving 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 invention has the beneficial effects that:
1. the invention adopts the reference source IC1 as overvoltage sampling detection, has high voltage detection precision, and can meet the application requirements only by adjusting the resistance values of R5 and R6 for different voltage requirements.
2. The invention realizes the detection of the input power supply voltage through the reference source, thereby controlling the on-off of the PMOS tube and solving the problem that the input voltage of the USB interface is possibly overhigh at present. 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 intelligent lock can effectively prevent the intelligent lock from being damaged when the input voltage is overhigh, and the protection circuit can also work normally when the battery is completely dead, so that the intelligent lock can be ensured to be normally used.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and 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 creative efforts.
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 examples, which are illustrative of the present invention and are not to be construed as being limited thereto.
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 C1, IC1 is conducted, and 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 invention also provides a charging device, which is used for charging the electronic device and is independent of the electronic device, and the internal structure of the charging device comprises the overvoltage protection circuit in the embodiment 1, and the 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 voltage; 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 invention also provides an electronic device, wherein the overvoltage protection circuit in 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 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 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. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments 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 of the structure, the characteristics and the principle of the invention which are described in the patent conception of the invention are included in the protection scope of the patent of the invention. Various modifications, additions and substitutions for the specific embodiments described 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)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010108996.3A CN111181129A (en) | 2020-02-21 | 2020-02-21 | Overvoltage protection circuit, charging equipment and electronic equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010108996.3A CN111181129A (en) | 2020-02-21 | 2020-02-21 | Overvoltage protection circuit, charging equipment and electronic equipment |
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| Publication Number | Publication Date |
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| CN111181129A true CN111181129A (en) | 2020-05-19 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010108996.3A Pending CN111181129A (en) | 2020-02-21 | 2020-02-21 | Overvoltage protection circuit, charging equipment and electronic equipment |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203166467U (en) * | 2013-03-20 | 2013-08-28 | 向智勇 | Overvoltage protection circuit |
| CN203707757U (en) * | 2013-12-20 | 2014-07-09 | Tcl通力电子（惠州）有限公司 | Overvoltage protection circuit and electronic equipment |
| CN104158147A (en) * | 2013-05-14 | 2014-11-19 | 海洋王（东莞）照明科技有限公司 | Overvoltage protection circuit and electronic equipment |
| CN104577993A (en) * | 2013-10-09 | 2015-04-29 | 珠海格力电器股份有限公司 | Input voltage protection circuit of switching power supply |
| CN104953539A (en) * | 2014-03-26 | 2015-09-30 | 国家电网公司 | Low-voltage-side overvoltage protection circuit |
| CN205987136U (en) * | 2016-08-30 | 2017-02-22 | 广州小百合信息技术有限公司 | Television board card power supply protection circuit |
| CN211351687U (en) * | 2020-02-21 | 2020-08-25 | 德施曼机电（中国）有限公司 | Overvoltage protection circuit, charging equipment and electronic equipment |
-
2020
- 2020-02-21 CN CN202010108996.3A patent/CN111181129A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203166467U (en) * | 2013-03-20 | 2013-08-28 | 向智勇 | Overvoltage protection circuit |
| CN104158147A (en) * | 2013-05-14 | 2014-11-19 | 海洋王（东莞）照明科技有限公司 | Overvoltage protection circuit and electronic equipment |
| CN104577993A (en) * | 2013-10-09 | 2015-04-29 | 珠海格力电器股份有限公司 | Input voltage protection circuit of switching power supply |
| CN203707757U (en) * | 2013-12-20 | 2014-07-09 | Tcl通力电子（惠州）有限公司 | Overvoltage protection circuit and electronic equipment |
| CN104953539A (en) * | 2014-03-26 | 2015-09-30 | 国家电网公司 | Low-voltage-side overvoltage protection circuit |
| CN205987136U (en) * | 2016-08-30 | 2017-02-22 | 广州小百合信息技术有限公司 | Television board card power supply protection circuit |
| CN211351687U (en) * | 2020-02-21 | 2020-08-25 | 德施曼机电（中国）有限公司 | Overvoltage protection circuit, charging equipment and electronic equipment |
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Country or region after: China Address after: 310051 floor 1-3, building 1, No.7 Jianghui South Road, Binjiang District, Hangzhou City, Zhejiang Province Applicant after: Zhejiang Deshiman Technology Intelligence Co.,Ltd. Address before: Floors 1-3, Building 1, No. 7 Jianghui South Road, Binjiang District, Hangzhou City, Zhejiang Province Applicant before: DESSMANN (CHINA) MACHINERY & ELECTRONIC Co.,Ltd. Country or region before: China |
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