CN217824234U - Overvoltage protection circuit and electronic equipment - Google Patents

Abstract

The application discloses overvoltage crowbar and electronic equipment. The overvoltage protection circuit includes: the control end of the first switch circuit is connected with a preset voltage; one end of the first input control circuit is a charging port, and the other end of the first input control circuit is connected with the first communication end of the first switch circuit and used for transmitting the charging voltage accessed by the charging port to the first communication end of the first switch circuit; and the control end of the second switch circuit is connected with the second communication end of the first switch circuit, the first communication end of the second switch circuit is used for being connected with the charging circuit, and the second communication end of the second switch circuit is connected with the other end of the first input control circuit. Through the mode, the charging/power supply overvoltage protection can be realized, and the service life of the electronic equipment and the circuit board thereof is prolonged.

Description

Overvoltage protection circuit and electronic equipment

technical field

The present application relates to the field of electronic technology, in particular to an overvoltage protection circuit and electronic equipment.

Background technique

Movable electronic devices, such as electric floating boards, etc., need to be charged through the equipped charger in order to realize their electric drive. However, in the actual application process, the user may use other unmatched chargers to charge the electronic device, that is, use a charger that does not meet the requirements for charging.

However, existing electronic equipment does not implement circuit protection for charging with unqualified chargers, which usually leads to overvoltage charging of electronic equipment, etc., resulting in direct damage to the circuit board inside the electronic equipment and shortening its service life.

Utility model content

The present application provides an overvoltage protection circuit and electronic equipment, so as to realize charging/power supply overvoltage protection and improve the service life of the electronic equipment and its circuit board.

In order to solve the above technical problems, the present application proposes an overvoltage protection circuit. The overvoltage protection circuit includes: a first switch circuit, the control end of the first switch circuit is connected to a preset voltage; a first input control circuit, one end of the first input control circuit is a charging port, and the other end of the first input control circuit Connected to the first communication end of the first switch circuit, used to transmit the charging voltage connected to the charging port to the first communication end of the first switch circuit; the second switch circuit, the control end of the second switch circuit and the first switch The second communication terminal of the circuit is connected, the first communication terminal of the second switch circuit is used for connecting with the charging circuit, and the second communication terminal of the second switch circuit is connected with the other terminal of the first input control circuit.

Wherein, the first input control circuit includes: a third switch circuit, the control end of the third switch circuit is connected to the second communication end of the first switch circuit, and the first communication end of the third switch circuit is used as one end of the first input control circuit As a charging port, the second communication end of the third switch circuit is connected to the second communication end of the second switch circuit as the other end of the first input control circuit; a diode, the anode of the diode is connected to the first communication end of the third switch circuit , the cathode of the diode is connected to the second communication end of the third switch circuit; the overvoltage protection circuit also includes: a second input control circuit, one end of the second input control circuit is connected to the charging port, and the other end of the second input control circuit is connected to the charging port. The second communication end of the third switch circuit is connected, and when the charging port is not connected to the charging voltage, the second input control circuit controls the first communication end of the third switch circuit to disconnect from the second communication end, so as to avoid voltage reversal of the charging circuit. Fill to the charging port.

Wherein, the overvoltage protection circuit further includes: a first clamping circuit, one end of the first clamping circuit is grounded, and the other end of the first clamping circuit is connected to the first switch circuit for providing a preset voltage.

Wherein, the first clamping circuit includes: a first voltage regulator tube, the anode of the first voltage regulator tube is grounded, and the cathode of the first voltage regulator tube is connected to the control terminal of the first switch circuit; a first resistor, one end of the first resistor It is connected with the cathode of the first regulator tube, and the other end of the first resistor is connected with the first communication end of the first switch circuit.

Wherein, the overvoltage protection circuit further includes: a second clamp circuit, one end of the second clamp circuit is connected to the control terminal of the second switch circuit, and the other end of the second clamp circuit is connected to the second communication terminal of the second switch circuit The connection is used to ensure the voltage difference between the control terminal of the second switch circuit and the second communication terminal.

Wherein, the first switch circuit includes a PNP transistor, the second switch circuit includes a first PMOS transistor, and the third switch circuit includes a second PMOS transistor, wherein the base of the PNP transistor is connected to a preset voltage, and the emitters of the PNP transistor are respectively connected to the The source of the first PMOS transistor is connected to the source of the second PMOS transistor, the collector of the PNP transistor is respectively connected to the gate of the first PMOS transistor and the gate of the second PMOS transistor, and the drain of the second PMOS transistor is the charging port , the drain of the first PMOS transistor is connected to the charging circuit.

Wherein, the second input control circuit includes: an NPN transistor, the base of the NPN transistor is connected to the charging port, the collector of the NPN transistor is connected to the gate of the second PMOS transistor, and the emitter of the NPN transistor is grounded.

Wherein, the second input control circuit further includes: a second resistor, one end of the second resistor is connected to the base of the NPN transistor, and the other end of the second resistor is connected to the emitter of the NPN transistor.

Wherein, the overvoltage protection circuit further includes: a third resistor, one end of the third resistor is connected to the gate of the first PMOS transistor, and the other end of the third resistor is connected to the collector of the NPN transistor.

Wherein, the overvoltage protection circuit further includes: a fourth resistor, one end of the fourth resistor is connected to the charging port, the other end of the fourth resistor is connected to the base of the NPN transistor; and/or a fifth resistor, one end of the fifth resistor is connected to the The gate of the first PMOS transistor is connected, the other end of the fifth resistor is connected to the source of the first PMOS transistor; and/or the sixth resistor, one end of the sixth resistor is connected to the preset voltage, and the other end of the sixth resistor is connected to the source of the first PMOS transistor. The base connection of the PNP transistor.

In order to solve the above technical problems, the present application proposes an electronic device. The electronic equipment includes the above-mentioned overvoltage protection circuit.

Different from the prior art: the overvoltage protection circuit of this application includes: a first switch circuit, a first input control circuit and a second switch circuit; wherein, the control terminal of the first switch circuit is connected to a preset voltage; the first input control circuit One end of the circuit is a charging port, and the other end of the first input control circuit is connected to the first communication end of the first switch circuit for transmitting the charging voltage connected to the charging port to the first communication end of the first switch circuit; The control end of the second switch circuit is connected to the second communication end of the first switch circuit, the first communication end of the second switch circuit is used to connect with the charging circuit, and the second communication end of the second switch circuit is connected to the first input control circuit. Connect the other end. The overvoltage protection circuit of the present application transmits the charging voltage connected to the charging port to the first switching circuit and the second switching circuit respectively through the first input control circuit, and controls the opening of the first switching circuit through the charging voltage to control the second switching circuit. The switch circuit is turned on, so that the charging voltage is transmitted to the charging circuit through the second switch circuit (the charging circuit may be an energy storage circuit of the electronic device, or a circuit that supplies power to the energy storage circuit and other circuits), so as to store electric energy for the electronic device; Alternatively, the first switch circuit is controlled to be turned on by the charging voltage to control the second switch circuit to be turned off, so as to stop transmitting the charging voltage to the charging circuit. Therefore, the present application can automatically control the conduction and disconnection of the first switch circuit and the second switch circuit according to the magnitude of the charging voltage, thereby automatically controlling the charging or power supply of the charging circuit by the charging voltage according to the magnitude of the charging voltage, and stopping charging or powered by. Therefore, the present application can stop the charging voltage to charge or supply power to the charging circuit when the charging voltage is greater than or equal to the sum of the preset voltage and the conduction voltage of the first communication terminal and the second communication terminal of the first switch circuit, so as to avoid Overvoltage charging or power supply, realize charging or power supply overvoltage protection, improve the life of electronic equipment and its circuit boards.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work, in which:

Fig. 1 is a structural schematic diagram of an embodiment of the overvoltage protection circuit of the present application;

Fig. 2 is the schematic diagram of the circuit structure of Fig. 1 embodiment;

Fig. 3 is a schematic structural diagram of an embodiment of the electronic device of the present application.

Detailed ways

The application will be described in further detail below in conjunction with the accompanying drawings and embodiments. In particular, the following examples are only used to illustrate the present application, but not to limit the scope of the present application. Likewise, the following embodiments are only some of the embodiments of the present application but not all of them, and all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

In the description of the embodiments of this application, it should be noted that unless otherwise specified and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, Or integrated connection; it can be mechanical connection or electrical connection; it can be direct connection or indirect connection through an intermediary. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present application in specific situations.

In the embodiment of the present application, unless otherwise clearly specified and limited, the first feature may be in direct contact with the first feature or the first feature and the second feature may pass through the middle of the second feature. Media indirect contact. Moreover, "above", "above" and "above" the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "beneath" and "beneath" the first feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is less horizontally than the second feature.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structures, materials or features are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

The present application first proposes an overvoltage protection circuit, as shown in FIG. 1 and FIG. 2 , FIG. 1 is a schematic structural diagram of an embodiment of the overvoltage protection circuit of the present application; FIG. 2 is a schematic circuit structural diagram of the embodiment in FIG. 1 . The overvoltage protection circuit (not marked in the figure) of this embodiment includes: a first switch circuit 11, a first input control circuit 12, and a second switch circuit 13; wherein, the control terminal of the first switch circuit 11 is connected to a preset voltage V1 One end of the first input control circuit 12 is the charging port POW, and the other end of the first input control circuit 12 is connected to the first communication end of the first switch circuit 11 for transmitting the charging voltage connected to the charging port POW to the first The first communication terminal of a switch circuit 11; the control terminal of the second switch circuit 13 is connected with the second communication terminal of the first switch circuit 11, and the first communication terminal of the second switch circuit 13 is used for charging circuit (not shown in the figure) , the port VBAT) is connected, and the second communication end of the second switch circuit 13 is connected with the other end of the first input control circuit 12 .

When the charging voltage is lower than the threshold voltage, the first communication terminal of the first switch circuit 11 is disconnected from the second communication terminal, and the first communication terminal of the second switch circuit 13 is connected to the second communication terminal to transmit the charging voltage to Charging circuit, to charge/power the charging circuit.

When the charging voltage is greater than or equal to the threshold voltage, the first communication end of the first switch circuit 11 is connected to the second communication end, and the first communication end of the second switch circuit 13 is disconnected from the second communication end to stop charging Circuit charging/power supply.

Wherein, the threshold voltage is the sum of the preset voltage V1 and the conduction voltage at which the first communication terminal and the second communication terminal of the first switch circuit 11 are conducted.

For example, in an application scenario, the preset voltage V1 can be 28V, and the conduction voltage at which the first communication terminal and the second communication terminal of the first switch circuit 11 are connected can be 1V, and the threshold voltage is 29V; when the charging voltage When it is lower than 29V, the first communication terminal of the first switch circuit 11 is disconnected from the second communication terminal, and the first communication terminal of the second switch circuit 13 is connected to the second communication terminal to transmit the charging voltage to the charging circuit. Charges/powers the charging circuit.

When the charging voltage is higher than or equal to 29V, the first communication end of the first switch circuit 11 is connected to the second communication end, and the first communication end of the second switch circuit 13 is disconnected from the second communication end to stop charging Circuit charging/power supply.

Wherein, the magnitude of the preset voltage V1 may be determined based on the performance parameters of the charging circuit and the power requirements of electronic devices such as electric floating boards, and is not specifically limited.

The turn-on voltage at which the first communication terminal and the second communication terminal of the first switch circuit 11 are connected may be determined based on performance parameters of components implementing the first switch circuit 11 .

Wherein, the charging circuit may be an energy storage circuit of electronic equipment such as an electric floating board, or a circuit for supplying power to the energy storage circuit and other circuits.

The overvoltage protection circuit of this embodiment transmits the charging voltage connected to the charging port POW to the first switch circuit 11 and the second switch circuit 13 respectively through the first input control circuit 12, and controls the first switch circuit 11 to turn off through the charging voltage. open, to control the conduction of the second switch circuit 13, so as to transmit the charging voltage to the charging circuit through the second switch circuit 13, so as to charge or supply power for electronic devices such as electric floating boards; or control the conduction of the first switch circuit through the charging voltage , so as to control the second switch circuit 13 to be turned off, so as to stop transmitting the charging voltage to the charging circuit. Therefore, this embodiment can automatically control the conduction and disconnection of the first switch circuit 11 and the second switch circuit 13 according to the magnitude of the charging voltage (specifically, the magnitude relationship between the charging voltage and the threshold voltage (fixed value), thereby According to the magnitude of the charging voltage, the charging voltage is automatically controlled to charge or supply power to the charging circuit and stop charging or supplying power. Therefore, in this embodiment, when the charging voltage is greater than or equal to the sum of the preset voltage and the conduction voltage at which the first communication terminal and the second communication terminal of the first switch circuit 11 are conducted, the charging voltage can be stopped to charge the charging circuit, so as to avoid Overvoltage charging or power supply, realize charging or power supply overvoltage protection, improve the life of electronic equipment and its circuit boards.

Optionally, the first input control circuit 12 of this embodiment includes: a third switch circuit (not shown) and a diode D; wherein, the control terminal of the third switch circuit is connected to the second communication terminal of the first switch circuit 11 , the first communication end of the third switch circuit is used as one end of the first input control circuit 12 as the charging port POW, and the second communication end of the third switch circuit is used as the other end of the first input control circuit 12 and the connection between the second switch circuit 13 The second communication terminal is connected; the anode of the diode D is connected to the first communication terminal of the third switch circuit, and the cathode of the diode D is connected to the second communication terminal of the third switch circuit.

Wherein, the diode D in this embodiment may be a parasitic diode, for example, may be a parasitic diode in the second PMOS transistor Q16 described below.

Optionally, the overvoltage protection circuit of this embodiment further includes: a second input control circuit 14, one end of the second input control circuit 14 is connected to the charging port POW, and the other end of the second input control circuit 14 is connected to the third switch circuit When the charging port POW is not connected to the charging voltage, the second input control circuit 14 controls the first communication terminal of the third switch circuit to disconnect from the second communication terminal, so as to prevent the voltage of the charging circuit from being fed back to the Charging port POW.

When the charging voltage is required to control the first switch circuit 11 to be turned off to control the second switch circuit 13 to be turned on, and to use the charging voltage to charge or supply power to the charging circuit, the charging port can be POW through the diode D of the first input control circuit 12. The input charging voltage is transmitted to the first switch circuit 11 and the second switch circuit 13 .

When charging is not required, disconnect the charging port POW, and there is no access to the charging port POW. At this time, the second input control circuit 14 is not turned on, so that the third switch circuit is disconnected, so as to avoid the voltage of the charging circuit (port VBAT) from decreasing. The three-switch circuit is fed back to the charging port POW.

Optionally, the first switch circuit 11 in this embodiment includes a PNP transistor Q15, the second switch circuit 13 includes a first PMOS transistor Q17, and the third switch circuit includes a second PMOS transistor Q16, wherein the base of the PNP transistor Q15 ( That is, the control terminal of the first switch circuit 11) is connected to the preset voltage, and the emitter of the PNP transistor Q15 (ie, the first communication terminal of the first switch circuit 11) is respectively connected to the source of the first PMOS transistor Q17 (ie, the second switch The second communication terminal of the circuit 13) and the source connection of the second PMOS transistor Q16 (ie, the second communication terminal of the third switch circuit), the collector of the PNP transistor Q15 (ie, the second communication terminal of the first switch circuit 11) They are respectively connected to the grid of the first PMOS transistor Q17 (ie, the control terminal of the second switch circuit 13) and the grid of the second PMOS transistor Q16 (ie, the control terminal of the third switch circuit), and the drain of the second PMOS transistor Q16 (that is, the first communication end of the third switch circuit) is the charging port POW, and the drain of the first PMOS transistor Q17 (that is, the first communication end of the second switch circuit 13 ) is connected to the charging circuit.

It should be noted that the second PMOS transistor Q16 in this embodiment includes the above-mentioned diode D, and the switching function of the third switch circuit is realized by the switch tube in the second PMOS transistor Q16, that is, the third switch circuit only corresponds to the second PMOS transistor Q16. The switching tube in tube Q16. Certainly, in other embodiments, the diode D and the third switch circuit may also be realized by using separate diodes and switch tubes.

Optionally, the second input control circuit 14 of this embodiment includes: an NPN transistor Q18, the base of the NPN transistor Q18 is connected to the charging port POW, the collector of the NPN transistor Q18 is connected to the gate of the second PMOS transistor Q16, and the NPN transistor Q18 is connected to the charging port POW. The emitter of the transistor Q18 is grounded.

When charging is not required, the charging port POW is disconnected, and there is no access to the charging port POW. At this time, the NPN transistor Q18 is not turned on, and the current of the charging circuit is from the port VBAT. The source of the first PMOS transistor Q17 is connected to the source of the second PMOS transistor Q16, and a part is from the source of the first PMOS transistor Q17 to the fifth resistor R54 to the gate of the second PMOS transistor Q16. The potential of the source electrode of the second PMOS transistor Q16 is approximately equal to the voltage of the port VBAT, and the potential of the gate of the second PMOS transistor Q16 is also approximately equal to the voltage of the port VBAT (the influence of the fifth resistor R54 and the second voltage regulator transistor D2 on the potential Negligible), there is basically no potential difference between the two, so the second PMOS transistor Q16 is not turned on, which can prevent the voltage of the charging circuit (port VBAT) from being fed back from the third switch circuit to the charging port POW.

Optionally, the overvoltage protection circuit of this embodiment further includes: a first clamping circuit 15, one end of the first clamping circuit 15 is grounded, and the other end of the first clamping circuit 15 is connected to the first switch circuit 11 for to provide a preset voltage.

Wherein, the first clamping circuit 15 of this embodiment includes: a first voltage regulator tube D1 and a first resistor R4; wherein, the anode of the first voltage regulator tube D1 is grounded, and the cathode of the first voltage regulator tube D1 is connected to the first switch The control end of the circuit 11 is connected; one end of the first resistor R4 is connected to the cathode of the first regulator tube D1 , and the other end of the first resistor R4 is connected to the first communication end of the first switch circuit 11 .

In this embodiment, the purpose of voltage stabilization can be achieved through the reverse connection of the first voltage regulator tube D1.

In an application scenario, the first switch circuit 11 can be implemented by a PNP transistor Q15, the cathode of the first regulator D1 is connected to the base of the PNP transistor Q15, and the other end of the first resistor R4 is connected to the emitter of the PNP transistor Q15 .

In this embodiment, the clamping circuit of the preset voltage is realized by the first regulator tube D1 and the first resistor R4, which can simplify the circuit structure and save costs. Certainly, in other embodiments, other circuits may also be used to realize the first clamping circuit 15 of this embodiment.

Further, the first voltage regulator tube D1 is connected in series with the first resistor R4, which can prevent the current from being too large when the first voltage regulator tube D1 reverses direction, and the current can be limited by the first resistor R4.

Optionally, the overvoltage protection circuit of this embodiment further includes: a sixth resistor R12, one end of the sixth resistor R12 is connected to a preset voltage, and the other end of the sixth resistor R12 is connected to the base of the PNP transistor Q15. The sixth resistor R12 is at least used for limiting the current of the base of the PNP transistor Q15. In this embodiment, one end of the sixth resistor R12 is connected to the cathode of the first regulator D1, and the other end of the sixth resistor R12 is connected to the base of the PNP transistor Q15.

In the above application scenario, when the charger is plugged into the charging port POW to charge or supply power to the charging circuit, if the charging voltage is less than 29V, the collector and emitter of the PNP transistor Q15 will not conduct, and the drain of the first PMOS transistor Q17 and The source is turned on, and the charging voltage is charged or powered to the electronic device from the port VBAT through the drain and source of the first PMOS transistor Q17; the voltage regulation value of the first voltage regulator D1 is 28V, so the PNP triode can be used in the circuit The potential of the base of Q15 is fixed at 28V. When the potential difference between the emitter and base of PNP transistor Q15 is greater than or equal to 1V, the collector and emitter of PNP transistor Q15 are turned on, and the collector of PNP transistor Q15 is The potential is determined by the charging voltage; if the charging voltage is higher than or equal to 29V, the collector and emitter of the PNP transistor Q15 are turned on, and the drain and source of the first PMOS transistor Q17 are no longer turned on. At this time, the charging voltage cannot pass through the second The second PMOS transistor Q16 and the first PMOS transistor Q17 charge or supply power to the electronic device from the port VBAT, thereby preventing the user from using an unqualified charger.

Furthermore, when the charging port POW is not connected to the charging voltage, the parasitic diode of the first PMOS transistor Q17 can reverse the voltage inside the electronic device from the port VBAT to the second PMOS transistor Q16, but because the base of the NPN transistor Q18 is not The input voltage, the collector and emitter of the NPN transistor Q18 are not conducting, and the source and drain of the second PMOS transistor Q16 are not conducting, which can control the second PMOS transistor Q16 when the charger is not inserted into the charging port POW It is non-conductive, which can prevent the voltage inside the electronic equipment such as electric floating from being fed back from the port VBAT to the charging port POW.

Optionally, the second input control circuit 14 of this embodiment further includes: a second resistor R63, one end of the second resistor R63 is connected to the base of the NPN transistor Q18, and the other end of the second resistor R63 is connected to the emitter of the NPN transistor Q18. pole connection. The second resistor R63 is at least used to pull down the base potential of the NPN transistor Q18 to prevent the NPN transistor Q18 from being misconducted.

Optionally, the overvoltage protection circuit of this embodiment further includes: a fourth resistor R62, one end of the fourth resistor R62 is connected to the charging port POW, and the other end of the fourth resistor R62 is connected to the base of the NPN transistor Q18. The fourth resistor R62 is at least used for limiting the current of the base of the NPN transistor Q18.

Optionally, the overvoltage protection circuit of this embodiment further includes: a second clamping circuit 16, one end of the second clamping circuit 16 is connected to the control terminal of the second switch circuit 13, and the other end of the second clamping circuit 16 It is connected with the second communication end of the second switch circuit 13 and is used to ensure the voltage difference between the control end of the second switch circuit 13 and the second communication end. In this way, the working stability of the second switch circuit 13 can be improved, thereby improving the working stability of the overvoltage protection circuit.

Wherein, the second clamping circuit 16 includes: a second voltage regulator transistor D2, the anode of the second voltage regulator transistor D2 is connected to the gate of the first PMOS transistor Q17, the cathode of the second voltage regulator transistor D2 is connected to the gate of the first PMOS transistor Q17 The source connection of the first PMOS transistor Q17 is used to ensure the voltage difference between the gate and the source of the first PMOS transistor Q17, and maintain the stable conduction of the first PMOS transistor Q17.

Optionally, the overvoltage protection circuit of this embodiment further includes: a fifth resistor R54, one end of the fifth resistor R54 is connected to the gate of the first PMOS transistor Q17, and the other end of the fifth resistor R54 is connected to the gate of the first PMOS transistor Q17 source connection. The fifth resistor R54 is at least used for voltage division.

Optionally, the overvoltage protection circuit of this embodiment further includes: a third resistor R61, one end of the third resistor R61 is connected to the gate of the first PMOS transistor Q17, and the other end of the third resistor R61 is connected to the collector of the NPN transistor Q18. Electrode connection.

Under normal charging (using a compliant charger), the third resistor R61 acts as a voltage divider. The PNP transistor Q15 is not conducting, the current of the charger flows from the charging port POW to the second PMOS transistor Q16, from the source to the drain of the second PMOS transistor Q16, to the source of the first PMOS transistor Q17, partly through the fifth From the resistor R54 to the third resistor R61, through the NPN transistor Q18 (in the conduction state), and then to the ground. The third resistor R61 acts as a voltage divider to ensure that the potential difference between the gate and source of the first PMOS transistor Q17 is not too large, so as to ensure the normal operation of the first PMOS transistor Q17.

In abnormal charging (non-compliant charger), the third resistor R61 acts as a current limiter, the PNP transistor Q15 is turned on, and the current of the charger flows from the charging port POW to the diode D, and then to the emitter of the PNP transistor Q15, Then to the collector of the PNP transistor Q15, along the path to the third resistor R61 and then to the ground through the NPN transistor Q18, the third resistor R61 can avoid excessive current in the loop and burn out the PNP transistor Q15 and NPN transistor Q18.

The third resistor R61 is connected in series with the second voltage regulator tube D2, and the reverse connection of the second voltage regulator tube D2 can show the effect of voltage stabilization, but when the second voltage regulator tube D2 is reversed, the current flowing through it should not be too large. The third resistor R61 can limit the current of the second regulator tube D2.

In other embodiments, any one or any combination of the above-mentioned first to sixth resistors may be selectively set.

In other embodiments, other types of switch tubes can be used to replace the above switch tubes, or other types of the same type (P-channel, N-channel) switch tubes can be used to replace the above-mentioned switch terminals, and the circuit can be adaptively adjusted .

The present application further proposes an electronic device, as shown in FIG. 3 , which is a schematic structural diagram of an embodiment of the electronic device of the present application. The electronic device (not shown) in this embodiment includes an overvoltage protection circuit 31 . The structure and working principle of the overvoltage protection circuit 31 can be referred to the above-mentioned embodiments.

Optionally, the electronic device in this embodiment further includes a charging circuit 32 and an energy storage circuit 33, wherein the charging circuit 32 and the overvoltage protection circuit 31 can be arranged on the control board 34 of the electronic device; wherein the overvoltage protection circuit 31 Connected to the charging circuit 32 , the overvoltage protection circuit 31 supplies the charging voltage to the charging circuit 32 , so that the charging circuit 32 supplies power to the control board 34 and charges the energy storage circuit 33 . The energy storage circuit 33 may be a battery or the like.

The electronic equipment of this application may be an electric floating board or other electronic equipment that needs to be charged by a charger.

Different from the prior art, the overvoltage protection circuit of the present application includes: a first switch circuit, a first input control circuit and a second switch circuit; wherein, the control terminal of the first switch circuit is connected to a preset voltage; the first input control circuit One end of the circuit is a charging port, and the other end of the first input control circuit is connected to the first communication end of the first switch circuit for transmitting the charging voltage connected to the charging port to the first communication end of the first switch circuit; The control end of the second switch circuit is connected to the second communication end of the first switch circuit, the first communication end of the second switch circuit is used to connect with the charging circuit, and the second communication end of the second switch circuit is connected to the first input control circuit. Connect the other end. The overvoltage protection circuit of the present application transmits the charging voltage connected to the charging port to the first switching circuit and the second switching circuit respectively through the first input control circuit, and controls the opening of the first switching circuit through the charging voltage to control the second switching circuit. The switch circuit is turned on, so that the charging voltage is transmitted to the charging circuit through the second switch circuit (the charging circuit may be an energy storage circuit of the electronic device, or a circuit that supplies power to the energy storage circuit and other circuits), so as to store electric energy for the electronic device; Alternatively, the first switch circuit is controlled to be turned on by the charging voltage to control the second switch circuit to be turned off, so as to stop transmitting the charging voltage to the charging circuit. Therefore, the present application can automatically control the conduction and disconnection of the first switch circuit and the second switch circuit according to the magnitude of the charging voltage, thereby automatically controlling the charging or power supply of the charging circuit by the charging voltage according to the magnitude of the charging voltage, and stopping charging or powered by. Therefore, the present application can stop the charging voltage to charge or supply power to the charging circuit when the charging voltage is greater than or equal to the sum of the preset voltage and the conduction voltage of the first communication terminal and the second communication terminal of the first switch circuit, so as to avoid Overvoltage charging or power supply, realize charging or power supply overvoltage protection, improve the life of electronic equipment and its circuit boards.

The above is only the implementation of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process conversion made by using the specification and drawings of the application, or directly or indirectly used in other related technologies fields, are all included in the scope of patent protection of this application in the same way.

Claims (11)

1. An overvoltage protection circuit, characterized in that, comprising: a first switch circuit, the control terminal of the first switch circuit is connected to a preset voltage; A first input control circuit, one end of the first input control circuit is a charging port, and the other end of the first input control circuit is connected to the first communication end of the first switch circuit for connecting the charging port The charged charging voltage connected is transmitted to the first communication terminal of the first switch circuit; The second switch circuit, the control end of the second switch circuit is connected to the second communication end of the first switch circuit, the first communication end of the second switch circuit is used to connect with the charging circuit, the second The second communication end of the switch circuit is connected to the other end of the first input control circuit. 2. The overvoltage protection circuit according to claim 1, wherein the first input control circuit comprises: A third switch circuit, the control end of the third switch circuit is connected to the second communication end of the first switch circuit, and the first communication end of the third switch circuit is used as the first input control circuit. One end is the charging port, and the second communication end of the third switch circuit is connected to the second communication end of the second switch circuit as the other end of the first input control circuit; a diode, the anode of the diode is connected to the first communication end of the third switch circuit, and the cathode of the diode is connected to the second communication end of the third switch circuit; The overvoltage protection circuit also includes: A second input control circuit, one end of the second input control circuit is connected to the charging port, the other end of the second input control circuit is connected to the second communication end of the third switch circuit, and the charging port When the charging voltage is not connected, the second input control circuit controls the first communication end of the third switch circuit to be disconnected from the second communication end, so as to prevent the voltage of the charging circuit from feeding back into the charging port. 3. The overvoltage protection circuit according to claim 1, further comprising: A first clamping circuit, one end of the first clamping circuit is grounded, and the other end of the first clamping circuit is connected to the first switch circuit for providing the preset voltage. 4. The overvoltage protection circuit according to claim 3, wherein the first clamping circuit comprises: a first voltage regulator tube, the anode of the first voltage regulator tube is grounded, and the cathode of the first voltage regulator tube is connected to the control terminal of the first switch circuit; A first resistor, one end of the first resistor is connected to the cathode of the first voltage regulator tube, and the other end of the first resistor is connected to the first communication end of the first switch circuit. 5. The overvoltage protection circuit according to claim 1, further comprising: A second clamping circuit, one end of the second clamping circuit is connected to the control end of the second switch circuit, and the other end of the second clamping circuit is connected to the second communication end of the second switch circuit , used to ensure the voltage difference between the control terminal of the second switch circuit and the second communication terminal. 6. The overvoltage protection circuit according to claim 2, wherein the first switch circuit includes a PNP transistor, the second switch circuit includes a first PMOS transistor, and the third switch circuit includes a second PMOS transistor, Wherein, the base of the PNP transistor is connected to the preset voltage, the emitter of the PNP transistor is respectively connected to the source of the first PMOS transistor and the source of the second PMOS transistor, and the PNP transistor The collector of the triode is respectively connected to the gate of the first PMOS transistor and the gate of the second PMOS transistor, the drain of the second PMOS transistor is the charging port, and the drain of the first PMOS transistor is Connect with the charging circuit. 7. The overvoltage protection circuit according to claim 6, wherein the second input control circuit comprises: An NPN transistor, the base of the NPN transistor is connected to the charging port, the collector of the NPN transistor is connected to the gate of the second PMOS transistor, and the emitter of the NPN transistor is grounded. 8. The overvoltage protection circuit according to claim 7, wherein the second input control circuit further comprises: A second resistor, one end of the second resistor is connected to the base of the NPN transistor, and the other end of the second resistor is connected to the emitter of the NPN transistor. 9. The overvoltage protection circuit according to claim 7, further comprising: A third resistor, one end of the third resistor is connected to the gate of the first PMOS transistor, and the other end of the third resistor is connected to the collector of the NPN transistor. 10. The overvoltage protection circuit according to claim 7, further comprising: A fourth resistor, one end of the fourth resistor is connected to the charging port, and the other end of the fourth resistor is connected to the base of the NPN transistor; and/or A fifth resistor, one end of the fifth resistor is connected to the gate of the first PMOS transistor, and the other end of the fifth resistor is connected to the source of the first PMOS transistor; and/or A sixth resistor, one end of the sixth resistor is connected to the preset voltage, and the other end of the sixth resistor is connected to the base of the PNP transistor. 11. An electronic device, comprising the overvoltage protection circuit according to any one of claims 1 to 10.

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