CN217115610U

CN217115610U - Overvoltage anti-reverse connection protection circuit

Info

Publication number: CN217115610U
Application number: CN202220364068.8U
Authority: CN
Inventors: 马振波; 沈文瑞; 王书仓
Original assignee: Zhejiang Sitis Technology Co ltd
Current assignee: Zhejiang Sitis Technology Co ltd
Priority date: 2022-02-22
Filing date: 2022-02-22
Publication date: 2022-08-02
Anticipated expiration: 2032-02-22

Abstract

The utility model discloses an anti transposition protection circuit of excessive pressure, including bleeder circuit, judgement circuit and output circuit, judge that the circuit includes steady voltage source Q1 and triode Q2, the output of bleeder circuit is connected to the input of steady voltage source Q1, the base of triode Q2 is connected to the output of steady voltage source Q1; the collector of the triode Q2 is connected with the anode of a voltage-stabilizing source Q1, and the emitter of the triode Q2 is connected with the source of a PMOS tube Q3 in the output circuit and is externally connected with a voltage source; the grid electrode of the PMOS pipe Q3 is connected with the collector electrode of the triode Q2, and the drain electrode is used as the positive output end of the overvoltage protection reverse connection protection circuit; the input end of the voltage division circuit is externally connected with a voltage source. The utility model provides an anti transposition protection circuit of excessive pressure simple structure, job stabilization nature is high, has only realized excessive pressure and anti transposition protection promptly through bleeder circuit, steady voltage source Q1, triode Q2 and PMOS pipe Q3. The utility model also provides a charger that contains foretell anti reverse connection protection circuit of excessive pressure.

Description

Overvoltage anti-reverse connection protection circuit

Technical Field

The utility model relates to a charging protection technical field, concretely relates to anti reverse connection protection circuit of excessive pressure.

Background

In the technical field of charging, overvoltage charging easily causes damage to a charging object (such as a battery), the service life of the charging object is shortened, and accidents such as fire disasters are easily caused under severe conditions. In addition, when the positive and negative poles of the charger are reversely connected with the positive and negative poles of the charging power supply, if the charger does not have the reverse connection prevention protection function, the charger can be damaged. At present, partial chargers on the market have overvoltage protection and anti-reverse connection protection functions, but the internal circuit structures of the chargers with the overvoltage and anti-reverse connection protection functions are generally complex, poor in anti-interference capability and low in working stability.

SUMMERY OF THE UTILITY MODEL

The utility model discloses with simplify charger internal circuit structure and realize excessive pressure and anti transposition protect function as the purpose, provide an excessive pressure anti transposition protect circuit.

To achieve the purpose, the utility model adopts the following technical proposal:

the overvoltage and reverse connection resisting protection circuit comprises a voltage division circuit, a judgment circuit and an output circuit, wherein the judgment circuit comprises a voltage-stabilizing source Q1 and a triode Q2, the input end of the voltage-stabilizing source Q1 is connected with the output end of the voltage division circuit, and the output end of the voltage-stabilizing source Q1 is connected with the base electrode of the triode Q2; the collector electrode of the triode Q2 is connected with the anode electrode of the voltage-stabilizing source Q1, and the emitter electrode of the triode Q2 is connected with the source electrode of a PMOS tube Q3 in the output circuit and is externally connected with a voltage source; the grid electrode of the PMOS pipe Q3 is connected with the collector electrode of the triode Q2, and the drain electrode of the PMOS pipe Q3 is used as the positive output end of the overvoltage reactance reverse connection protection circuit; the input end of the voltage division circuit is externally connected with a voltage source.

As a preferred scheme of the utility model, bleeder circuit includes resistance R1, R2, R8, resistance R1's one end is as bleeder circuit's input is external the voltage source, and the other end is connected resistance R8's one end, another termination of resistance R8 resistance R2's one end, resistance R2's other end ground connection.

As a preferable scheme of the present invention, the determining circuit further includes resistors R3, R4, R5, and R7, one end of the resistor R3 is connected to the voltage source and to the emitter of the transistor Q2, and the other end of the resistor R7 is connected in series to the cathode of the voltage regulator Q1 after being connected to the resistor R7 and to the base of the transistor Q2 after being connected to the resistor R4 in series; the reference electrode and the cathode of the voltage-stabilizing source Q1 are connected in parallel with two ends of a resistor R2 in the voltage-dividing circuit; the collector of the triode Q2 is connected in series with the resistor R5 and then grounded.

As a preferable aspect of the present invention, the output circuit further includes a resistor R6 connected between the gate and the source of the PMOS transistor Q3.

As a preferred aspect of the present invention, the overvoltage protection circuit further includes a capacitor C1, and the capacitor C1 is connected in parallel at two ends of the resistor R1 and the resistor R2 which are connected in series.

As an optimized scheme of the utility model, the anti transposition protection circuit of excessive pressure still includes zener diode D2, zener diode D2's positive pole is connected triode Q2's collecting electrode, and the negative pole is connected triode Q2's projecting pole.

As a preferred scheme of the utility model, the model of steady voltage source Q1 is TL 431.

The utility model also provides a charger, laid in the charger excessive pressure anti-reverse connection protection circuit.

The utility model provides an anti transposition protection circuit of excessive pressure simple structure, job stabilization nature is high, has only realized the protection of excessive pressure and anti transposition promptly through bleeder circuit, steady voltage source Q1, triode Q2 and PMOS pipe Q3.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below. It is obvious that the drawings described below are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a schematic circuit diagram of an overvoltage reverse connection protection circuit according to an embodiment of the present invention.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.

Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; for a better understanding of the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not indicated or implied that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are used only for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms will be understood by those skilled in the art according to the specific circumstances.

In the description of the present invention, unless otherwise explicitly specified or limited, the term "connected" or the like, if appearing to indicate a connection relationship between the components, is to be understood broadly, for example, as being either a fixed connection, a detachable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through one or more other components or may be in an interactive relationship with one another. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The embodiment of the utility model provides an anti reverse protection circuit that connects of excessive pressure, as shown in fig. 1, including bleeder circuit 100, judgement circuit 200 and output circuit 300, bleeder circuit 100 includes resistance R1, R2, R8, and resistance R1's one end is as bleeder circuit's the external voltage source of input (like 24V), and other end connecting resistance R8's one end, resistance R8's another termination resistance R2's one end, resistance R2's other end ground connection;

the judgment circuit comprises a voltage-stabilizing source Q1, a triode Q2, resistors R3, R4, R5 and R7, wherein one end of the resistor R3 is connected with a voltage source and is connected with an emitter of the triode Q2, the other end of the resistor R3 is connected with a cathode (serving as an output end of the voltage-stabilizing source Q1) of the voltage-stabilizing source Q1 after being connected with the resistor R7 in series, and is connected with a base of the triode Q2 after being connected with the resistor R4 in series; a reference electrode and a cathode (as an input end of a voltage regulator Q1) of a voltage regulator Q1 are connected in parallel with two ends (as an output end of the voltage divider circuit) of a resistor R2 in the voltage divider circuit; the collector of the triode Q2 is connected with the resistor R5 in series and then is grounded;

the output circuit comprises a PMOS pipe Q3 and a resistor R6 connected between the grid and the source of the PMOS pipe Q3, the source of the PMOS pipe Q3 is connected with the emitter of a triode Q2 in the judging circuit, the grid of the PMOS pipe Q3 is connected with the collector of the triode Q2, and the drain is used as the positive output end of the overvoltage protection and reverse connection protection circuit.

As shown in fig. 1, when the PMOS transistor Q3 is to operate, UGS (voltage between gate and source) <0 is required, and if the polarity of the input voltage is reversed, UGS of the PMOS transistor >0, at this time, the MOS transistor Q3 is turned off and does not operate, and the circuit has no output, and thus, the function of reverse connection protection is achieved. (reference numeral A, B, C in fig. 1 denotes input terminals of the voltage dividing circuit, the judgment circuit, and the output circuit, respectively).

In order to stabilize the input current, a capacitor C1 is added to perform a filtering function, as shown in fig. 1, the overvoltage protection circuit further includes a capacitor C1, and the capacitor C1 is connected in parallel across the series-connected resistor R1 and resistor R2.

In order to protect the MOS transistor Q3 from being broken through by overvoltage, a 10V regulator Q1 is added to prevent the source and gate voltages from exceeding 10V, and to protect the MOS transistor Q3 to a certain extent, as shown in fig. 1, the overvoltage protection circuit further includes a zener diode D2, the positive electrode of the zener diode D2 is connected to the collector of the transistor Q2, and the negative electrode of the zener diode D2 is connected to the emitter of the transistor Q2.

In this embodiment, the model of the voltage regulator D1 is preferably TL431, where TL431 is used as a switch, when a reference voltage of TL431 is less than 2.5V, TL431 is in a closed state, and when the reference voltage reaches 2.5V, TL431 is in a working state, and since a reference voltage thereof is precise and stable and has good temperature stability, when an input voltage changes, TL431 can accurately make a judgment, so that it can accurately control whether an output is present or not.

The working principle of the overvoltage reverse connection protection circuit provided by the embodiment is briefly explained as follows:

the resistors R1 and R2 in the voltage divider circuit 100 divide the input voltage, and when the input voltage is equal to or lower than a first threshold voltage (e.g., 30V), the voltage across the R2 is lower than a second threshold voltage (e.g., 2.5V), and at this time, the TL431 does not operate; when the input voltage exceeds the first threshold voltage (e.g., reaches 31V), the voltage across R2 exceeds the second threshold voltage, and TL431 operates normally.

When the reference voltage of the TL431 is smaller than the second threshold voltage, the TL431 is in an off state, the cathode current of the TL431 is only dozens of milliamperes, the base voltage of the triode Q2 is basically equal to the emitter voltage of the triode Q2, and the triode Q2 is in an off state; when the reference voltage of TL431 reaches the second threshold voltage, TL431 normally operates, and the emitter and base voltages of transistor Q2 are greater than the turn-on voltage (e.g., 0.7V), and transistor Q2 is turned on in saturation.

When the triode Q2 is cut off, a PMOS tube Q3 in the output circuit is conducted, and the overvoltage reactance reverse connection protection circuit has output; when the triode Q2 is turned on, the PMOS transistor Q3 is turned off, and the anti-reverse overvoltage protection circuit has no output, that is, when the input voltage exceeds the first threshold voltage, the output of the anti-reverse overvoltage protection circuit is turned off, thereby performing the function of overvoltage protection.

When the PMOS tube Q3 needs to work, UGS is less than 0, if the polarity of input voltage is reversed, UGS of the PMOS tube is greater than 0, at the moment, the MOS tube is cut off and does not work, the circuit has no output, and the function of reverse connection prevention protection is achieved. (reference numerals A, B, C in FIG. 1 denote voltage dividing circuits, respectively

Additionally, the utility model also provides a charger (like the electric vehicle charging ware), laid foretell anti reverse protection circuit of connecing of excessive pressure in this charger.

It should be understood that the above-described embodiments are merely illustrative of the preferred embodiments of the present invention and the technical principles thereof. It will be understood by those skilled in the art that various modifications, equivalents, changes, and the like can be made to the present invention. However, these modifications are within the scope of the present invention as long as they do not depart from the spirit of the present invention. In addition, certain terms used in the specification and claims of the present application are not limiting, but are used merely for convenience of description.

Claims

1. An overvoltage anti-reverse connection protection circuit is characterized by comprising a voltage division circuit, a judgment circuit and an output circuit, wherein the judgment circuit comprises a voltage-stabilizing source Q1 and a triode Q2, the input end of the voltage-stabilizing source Q1 is connected with the output end of the voltage division circuit, and the output end of the voltage-stabilizing source Q1 is connected with the base electrode of the triode Q2; the collector electrode of the triode Q2 is connected with the anode electrode of the voltage-stabilizing source Q1, and the emitter electrode of the triode Q2 is connected with the source electrode of a PMOS tube Q3 in the output circuit and is externally connected with a voltage source; the grid electrode of the PMOS pipe Q3 is connected with the collector electrode of the triode Q2, and the drain electrode of the PMOS pipe Q3 is used as the positive output end of the overvoltage reactance reverse connection protection circuit; the input end of the voltage division circuit is externally connected with a voltage source.

2. The protection circuit of claim 1, wherein the voltage divider circuit comprises resistors R1, R2, and R8, one end of the resistor R1 is connected to the voltage source as the input end of the voltage divider circuit, the other end of the resistor R1 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to ground.

3. The protection circuit of claim 1 or 2, wherein the determining circuit further comprises resistors R3, R4, R5, and R7, one end of the resistor R3 is connected to the voltage source and to the emitter of the transistor Q2, and the other end is connected in series with the resistor R7, then connected to the cathode of the voltage regulator Q1, and connected in series with the resistor R4, then connected to the base of the transistor Q2; the reference electrode and the cathode of the voltage-stabilizing source Q1 are connected in parallel with two ends of a resistor R2 in the voltage-dividing circuit; the collector of the triode Q2 is connected in series with the resistor R5 and then grounded.

4. The protection circuit of claim 3, wherein the output circuit further comprises a resistor R6 connected between the gate and source of the PMOS transistor Q3.

5. The protection circuit of claim 2, further comprising a capacitor C1, wherein the capacitor C1 is connected in parallel across the series connection of the resistor R1 and the resistor R2.

6. The protection circuit of claim 3, further comprising a zener diode D2, wherein the zener diode D2 has an anode connected to the collector of the transistor Q2 and a cathode connected to the emitter of the transistor Q2.

7. The protection circuit of claim 1, wherein the regulator Q1 is model TL 431.

8. A charger, characterized in that an overvoltage reverse-connection-resisting protection circuit according to any one of claims 1 to 7 is arranged in the charger.