CN217769460U - Overvoltage protection circuit, power supply system and electronic equipment - Google Patents
Overvoltage protection circuit, power supply system and electronic equipment Download PDFInfo
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- CN217769460U CN217769460U CN202221185414.2U CN202221185414U CN217769460U CN 217769460 U CN217769460 U CN 217769460U CN 202221185414 U CN202221185414 U CN 202221185414U CN 217769460 U CN217769460 U CN 217769460U
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Abstract
The application discloses prevent overvoltage crowbar, power supply system and electronic equipment, prevent that overvoltage crowbar includes the signal receiving terminal that charges, on-off circuit, supply circuit, prevent overvoltage crowbar, control signal end and power supply output, the signal receiving terminal that charges is used for receiving the signal of charging, the signal receiving terminal that charges is used for making on-off circuit switch on when receiving the signal of charging, supply circuit predetermines safe voltage to the output of power supply output when on-off circuit switches on, the control signal end is used for receiving control signal, prevent that overvoltage crowbar is used for restricting the signal of charging and switches on from the signal receiving terminal that charges to the control signal end, prevent that overvoltage crowbar still is used for restricting control signal and switches on from the signal receiving terminal that charges to the signal receiving terminal that charges. The design can effectively reduce the possibility of damage to the devices of the electronic equipment caused by overvoltage.
Description
Technical Field
The application relates to the technical field of power supply systems, in particular to an overvoltage protection circuit, a power supply system and electronic equipment.
Background
With the popularization of the scheme of rapid charging (rapid charging for short, a charging method capable of enabling a storage battery to reach or approach a charging saturation state within 1-5 hours) of electronic products. In rapid charging, overvoltage often occurs, for example, overvoltage occurring in case of misoperation and the like easily causes damage to devices of electronic products. Therefore, how to effectively reduce the possibility of device damage of electronic products caused by overvoltage has become an urgent problem to be solved.
SUMMERY OF THE UTILITY MODEL
The embodiment of the application provides an overvoltage protection circuit, a power supply system and electronic equipment, which can effectively reduce the possibility of damage to devices of the electronic equipment caused by overvoltage.
In a first aspect, an embodiment of the present application provides an overvoltage protection circuit; the overvoltage protection circuit comprises a charging signal receiving end, an on-off circuit, a power supply circuit, an overvoltage protection circuit, a control signal end and a power supply output end, wherein the charging signal receiving end is connected with the charging circuit to receive a charging signal, the charging signal receiving end is connected with the on-off circuit to conduct the on-off circuit when receiving the charging signal, the power supply circuit is sequentially connected with the on-off circuit and the power supply output end to output a preset safe voltage to the power supply output end when the on-off circuit is conducted, the control signal is connected with an external circuit to receive the control signal, the overvoltage protection circuit is connected between the control signal and the on-off circuit to limit the conduction of the charging signal from the charging signal receiving end to the control signal end, and the overvoltage protection circuit is further connected between the charging signal receiving end and the on-off circuit to limit the conduction of the control signal from the control signal end to the charging signal receiving end.
According to the overvoltage protection circuit, the on-off circuit is conducted when receiving the charging signal, so that the power supply circuit outputs the preset safe voltage to the power supply output end, normal work of an external circuit can be guaranteed, and the external circuit cannot be burnt out; the overvoltage preventing circuit is designed between the charging signal receiving end and the on-off circuit, so that the charging signal can be conducted from the charging signal receiving end to the on-off circuit only, and the control signal is prevented from flowing from the control signal end to the charging signal receiving end, and the effect of preventing the control signal from flowing back is achieved; the overvoltage protection circuit is designed between the control signal end and the on-off circuit, so that the control signal can be conducted from the control signal end to the on-off circuit, and the charging signal can be effectively prevented from being conducted from the charging signal end to the control signal end, and the possibility that an external circuit (such as an MCU (microprogrammed control Unit), a chip and the like) is burnt due to the overlarge charging signal caused by overvoltage can be effectively avoided.
In a second aspect, an embodiment of the present application provides a power supply system, where the power supply system includes a charging circuit and the above-mentioned overvoltage protection circuit, and the charging circuit is connected to the charging signal receiving terminal to provide a charging signal to the charging signal receiving terminal.
Based on the power supply system in the embodiment of the application, the power supply system with the overvoltage protection circuit can effectively avoid the possibility that an external circuit is burnt out due to overlarge charging voltage caused by overvoltage.
In a third aspect, an embodiment of the present application provides an electronic device, where the electronic device includes a housing and the power supply system described above, and the power supply system is disposed in the housing.
Based on the electronic equipment in the embodiment of the application, the electronic equipment with the power supply system can effectively avoid the possibility that the external circuit is burnt out due to overlarge charging voltage caused by overvoltage.
Drawings
In order to more clearly illustrate the embodiments of the present application 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, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic partial circuit diagram of an embodiment of an overvoltage protection circuit according to the present application;
FIG. 2 is a circuit diagram of a voltage step-down circuit according to an embodiment of the present application;
fig. 3 is a circuit diagram of a charge determination circuit according to an embodiment of the present application.
Reference numerals are as follows: 1. an overvoltage protection circuit; vusb, a charging signal receiving end; 11. a switching circuit; q1, a first electronic switch; q2, a second electronic switch; r13 and a third resistor; 12. a power supply circuit; + BAT, preset safe voltage; 13. an overvoltage protection circuit; d1, a first switching element; d2, a second switching element; d3, a third switching element; PWR-ON, control signal terminal; BAT-OUT, power supply output terminal; 14. a trigger circuit; s1, a fourth switching element; r11 and a first resistor; r12 and a second resistor; b1, a first node; KEY-PWR, detection signal end; 15. a voltage step-down circuit; u1 and a control chip; 16. a charge determination circuit; USB-CHGIN, a judgment signal output end; r14 and a fourth resistor; r15 and a fifth resistor; q3, a third electronic switch; VCC, reference voltage; b2, a second node; 21. a charging circuit.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
With the popularization of the scheme of rapid charging (rapid charging for short, a charging method capable of enabling a storage battery to reach or approach a charging saturation state within 1-5 hours) of electronic products. In rapid charging, an overvoltage condition often occurs, for example, the overvoltage condition occurs in the case of misoperation, etc., which easily causes the device of the electronic product to be damaged. Here, "malfunction" should be understood as a case of a malfunction causing the input voltage of the USB interface to be excessively large to exceed the normal charging voltage.
For example, in some application scenarios, the input voltage of a USB (Universal Serial Bus) interface can be up to 20 volts due to the insertion of the positive and negative electrodes of the USB interface, and overvoltage causes device damage of electronic products.
Therefore, how to effectively reduce the possibility of device damage of electronic products caused by overvoltage has become an urgent problem to be solved.
In order to solve the above technical problem, referring to fig. 1, a first aspect of the present application provides an overvoltage protection circuit 1, which can effectively reduce the possibility of device damage of an electronic device caused by overvoltage.
The overvoltage protection circuit 1 comprises a charging signal receiving end Vusb, an ON-off circuit 11, a power supply circuit 12, an overvoltage protection circuit 13, a control signal end PWR-ON and a power supply output end BAT-OUT.
The charging signal receiving terminal Vusb is used for being connected with the charging circuit 21 (shown in fig. 2) to receive a charging signal, the charging signal receiving terminal Vusb is connected with the ON-off circuit 11 to turn ON the power-ON circuit when receiving the charging signal, the power supply circuit 12 is sequentially connected with the ON-off circuit 11 and the power supply output terminal BAT-OUT to output a preset safe voltage + BAT to the power supply output terminal BAT-OUT when the ON-off circuit 11 is turned ON, the control signal terminal PWR-ON is used for being connected with an external circuit to receive a control signal, the overvoltage protection circuit 13 is connected between the control signal terminal PWR-ON and the ON-off circuit 11 to limit the conduction of the charging signal from the charging signal receiving terminal Vusb to the control signal terminal PWR-ON, and the overvoltage protection circuit 13 is further connected between the charging signal receiving terminal Vusb and the ON-off circuit 11 to limit the conduction of the control signal from the control signal terminal PWR-ON to the charging signal receiving terminal Vusb.
The following description is made with reference to fig. 1 to 3 for a specific circuit structure of the overvoltage protection circuit 1, where the overvoltage protection circuit 1 includes a charging signal receiving terminal Vusb, an ON-off circuit 11, a power supply circuit 12, an overvoltage protection circuit 13, a control signal terminal PWR-ON, and a power supply output terminal BAT-OUT.
As shown in fig. 1, the charging signal receiving terminal Vusb corresponds to a port for receiving a charging signal in the overvoltage protection circuit 1, the charging signal receiving terminal Vusb is used for connecting with the charging circuit 21 to receive a charging signal, and the "charging circuit 21" may be a circuit for delivering electric energy by the overvoltage protection circuit 1, for example, a USB charging circuit. The charging circuit 21 is generally used to connect with an external power source, so that the electric energy of the external power source is transmitted to the overvoltage protection circuit 1 through the charging circuit 21. The "charging signal" may be a voltage signal or a current signal supplied to the charging signal receiving terminal Vusb by the charging circuit 21, for example, when the charging signal is a voltage signal, the charging signal may be 5 volts under normal operation, and the charging signal may be up to 20 volts under misoperation, which easily causes overvoltage.
The on-off circuit 11 corresponds to a circuit structure for controlling the circuit to be turned on or off in the overvoltage protection circuit 1, and a specific circuit structure of the on-off circuit 11 will be described later.
The charging signal receiving terminal Vusb is connected to the on-off circuit 11, so as to turn on the on-off circuit 11 when receiving a charging signal, that is, the charging signal is used as an electrical signal for controlling the on-off circuit 11 to be turned on or off, the on-off circuit 11 is turned on when receiving the charging signal, and the on-off circuit 11 is turned off when not receiving the charging signal.
The power supply output terminal BAT-OUT corresponds to a power supply port for connecting with an external circuit in the overvoltage protection circuit 1. The "external circuit" may be a circuit that supplies power through the overvoltage protection circuit 1 to achieve normal operation, and for example, the external circuit may be, but is not limited to, an MCU (micro control Unit), a controller, and the like.
The power supply circuit 12 corresponds to a circuit configuration for supplying electric power to an external circuit in the overvoltage protection circuit 1, and a specific circuit configuration of the power supply circuit 12 will be described later.
The power supply circuit 12 is sequentially connected with the on-off circuit 11 and the power supply output terminal BAT-OUT, the power supply circuit 12 outputs a preset safe voltage + BAT to the power supply output terminal BAT-OUT when the on-off circuit 11 is turned on, that is, the preset safe voltage + BAT output by the power supply circuit 12 needs to be output to the power supply output terminal BAT-OUT through the on-off circuit 11, and when the on-off circuit 11 is turned on, the power supply circuit 12 outputs the preset safe voltage + BAT to the power supply output terminal BAT-OUT. And when the on-off circuit 11 is turned off, the power supply circuit 12 generally cannot output the preset safe voltage + BAT to the power supply output terminal BAT-OUT. The "preset safe voltage + BAT" may be an output voltage output by the power supply circuit 12, which may ensure that the external circuit works normally and may not burn out the external circuit, and the preset safe voltage + BAT may be an output voltage indirectly formed by the power supply circuit 12 after a voltage reduction operation of a circuit structure (such as a charging IC of the voltage reduction circuit 15 described below), or the preset safe voltage + BAT may be an output voltage directly formed by the power supply circuit 12 without passing through any other circuit structure. The anti-overvoltage protection circuit 1 has the function of charging overvoltage protection, and the reliability and stability of the circuit are high.
The control signal terminal PWR-ON corresponds to a port of the overvoltage protection circuit 1 for connection with an external circuit to receive a control signal output from the external circuit.
The overvoltage protection circuit 13 corresponds to a circuit configuration for realizing overvoltage protection in the overvoltage protection circuit 1, wherein "overvoltage protection" may be a circuit configuration that limits the actual voltage flowing through the line to be protected when the actual voltage exceeds a maximum predetermined voltage. The specific circuit structure of the overvoltage protection circuit 13 will be described later.
The overvoltage protection circuit 13 is connected between the control signal terminal PWR-ON and the ON-off circuit 11, and the overvoltage protection circuit 13 is used for limiting the conduction of the charging signal from the charging signal receiving terminal Vusb to the control signal terminal PWR-ON, that is, the overvoltage protection circuit 13 can make the control signal from the control signal terminal PWR-ON to the ON-off circuit 11, but the charging signal cannot be conducted from the charging signal receiving terminal Vusb to the control signal terminal PWR-ON. Therefore, when the charging signal output by the charging circuit 21 is too large, the design of the overvoltage protection circuit 13 can effectively avoid the possibility that the external circuit (e.g., MCU, chip, etc.) is burned due to the too large charging signal.
The overvoltage protection circuit 13 is further connected between the charging signal receiving terminal Vusb and the ON-off circuit 11, and the overvoltage protection circuit 13 is configured to limit the control signal from the control signal terminal PWR-ON to the charging signal receiving terminal Vusb, that is, the overvoltage protection circuit 13 can enable the charging signal from the charging signal receiving terminal Vusb to the ON-off circuit 11, but the control signal cannot be generally conducted from the control signal terminal PWR-ON to the charging signal receiving terminal Vusb. Therefore, when the control signal terminal PWR-ON receives a control signal from an external circuit, the design of the overvoltage protection circuit 13 can effectively prevent the control signal from being conducted from the control signal terminal PWR-ON to the charging signal receiving terminal Vusb, so as to prevent the control signal from flowing back.
Based on the overvoltage protection circuit 1 in the embodiment of the application, the on-off circuit 11 is turned on when receiving a charging signal, so that the power supply circuit 12 outputs a preset safe voltage + BAT to the power supply output terminal BAT-OUT, and the external circuit can be ensured to normally work and cannot be burnt OUT; by designing the overvoltage protection circuit 13 between the charging signal receiving terminal Vusb and the ON-off circuit 11, the charging signal can only reach the ON-off circuit 11 from the charging signal receiving terminal Vusb, and the control signal is prevented from reaching the charging signal receiving terminal Vusb from the control signal terminal PWR-ON, so that the control signal backflow is prevented; by designing the overvoltage protection circuit 13 between the control signal terminal PWR-ON and the ON-off circuit 11, the control signal can be only transmitted from the control signal terminal PWR-ON to the ON-off circuit 11, and the charging signal can be effectively prevented from being transmitted from the charging signal terminal to the control signal terminal PWR-ON, so that the possibility of burning out an external circuit due to the overlarge charging signal caused by overvoltage can be effectively avoided.
As shown in fig. 1, in view of the fact that the overvoltage preventing circuit 13 can make the control signal from the control signal terminal PWR-ON to the ON-off circuit 11 and restrict the charging signal from the charging signal receiving terminal Vusb to the control signal terminal PWR-ON, in order to make the overvoltage preventing circuit 13 have this function, it is designed that in some embodiments, the overvoltage preventing circuit 13 includes a first switching element D1, the first switching element D1 is connected between the control signal terminal PWR-ON and the ON-off circuit 11, the control signal terminal PWR-ON is used to input the control signal to the ON-off circuit 11 to make the ON-off circuit 11 ON, the first switching element D1 is used to make the control signal from the control signal terminal PWR-ON to the ON-off circuit 11, and the first switching element D1 is also used to restrict the charging signal from the charging signal receiving terminal Vusb to the control signal terminal PWR-ON.
The first switching element D1 may be a unidirectional conducting element, and the first switching element D1 is unidirectionally conducted by the control signal, so that the control signal can only be transmitted from the control signal terminal PWR-ON to the ON-off circuit 11, and a detailed expression of the first switching element D1 will be described below. Control
The control signal is another electrical signal for controlling the on/off of the on/off circuit 11, like the charging signal, the on/off circuit 11 is turned on when receiving the control signal, and the on/off circuit 11 is turned off when not receiving the control signal. It should be noted that the control signal may be an electrical signal formed by an external circuit, for example, an electrical signal formed by one of fingerprint recognition, face recognition, pressing, and touch. In this design, by designing the first switching element D1, ON the one hand, the first switching element D1 is turned ON under the action of the control signal, so that the control signal can be turned ON from the control signal terminal PWR-ON to the ON-off circuit 11, thereby turning ON the ON-off circuit 11, and the ON-off circuit 11 is turned ON, so that the power supply circuit 12 outputs the preset safe voltage + BAT to the power supply output terminal BAT-OUT, thereby supplying power to an external circuit connected to the power supply output terminal BAT-OUT. ON the other hand, the first switch element D1 can effectively limit the conduction of the charging signal from the charging signal receiving terminal Vusb to the control signal terminal PWR-ON, so that when the charging signal of the charging circuit 21 is too large due to a malfunction, the design of the first switch element D1 can effectively avoid the possibility of burning out the external circuit due to the too large charging signal.
As shown in fig. 1, in an embodiment, the overvoltage protection circuit 1 further includes a trigger circuit 14, the trigger circuit 14 is connected to the power supply circuit 12, and the overvoltage protection circuit 13 is further connected between the trigger circuit 14 and the on-off circuit 11. The overvoltage protection circuit 13 further includes a second switching element D2, the second switching element D2 is connected between the trigger circuit 14 and the on-off circuit 11, the second switching element D2 is configured to enable the trigger signal of the trigger circuit 14 to flow from the trigger circuit 14 to the on-off circuit 11, and the second switching element D2 is further configured to limit the charging signal from the charging signal receiving terminal Vusb to the trigger circuit 14.
The trigger circuit 14 is a circuit structure of the overvoltage protection circuit 1 that is used to realize the conduction of the on-off circuit 11 through a touch operation of a user, and a specific circuit structure of the trigger circuit 14 will be described below. The second switching element D2 is a unidirectional conducting element, and the second switching element D2 is unidirectional conducting under the action of the trigger signal, so that the trigger signal can only be from the trigger circuit 14 to the on-off circuit 11, and the specific expression of the second switching element D2 will be described later.
The trigger signal may be an electrical signal formed under the operation of the user, for example, the operation of touch, pressing, toggling, etc., the trigger signal may be another electrical signal that is used as the charging signal to control the on/off of the on/off circuit 11, the on/off circuit 11 is turned on when receiving the trigger signal, and the on/off circuit 11 is turned off when not receiving the trigger signal. Of course, the trigger signal may also be another electrical signal that controls the on/off of the on/off circuit 11 in cooperation with the control signal, the on/off circuit 11 is turned on when receiving the control signal, and the on/off circuit 11 is turned off when not receiving the control signal, and at this time, the trigger signal cannot turn on the on/off circuit 11. It is understood that the trigger circuit 14 is connected to the power supply circuit 12, so that the trigger signal formed by the trigger circuit 14 can be an output voltage (e.g., the predetermined safety voltage + BAT) of the power supply circuit 12.
In the design, the trigger circuit 14 is connected with the power supply circuit 12, the trigger signal formed by the trigger circuit 14 can be the output voltage of the power supply circuit 12, and other circuit structures do not need to be additionally designed to provide the trigger signal, so that the whole circuit structure of the overvoltage protection circuit 1 can be simplified. Through designing second switch element D2, second switch element D2 switches on under trigger signal's effect on the one hand, makes trigger signal can switch on from trigger circuit 14 to on-off circuit 11, and second switch element D2 can effectively restrict the signal of charging and switch on from charging signal receiving terminal Vusb to trigger circuit 14 on the other hand, so when the signal of charging that leads to charging circuit 21 because of the maloperation is too big, the possibility of burning out power supply circuit 12 because of the signal of charging is too big can effectively be avoided in second switch element D2's design.
In some application scenarios, the trigger circuit 14 needs to realize the conduction of the on-off circuit 11 under the touch operation of a user, and the conduction of the on-off circuit 11 can enable the power supply circuit 12 to output a preset safe voltage + BAT to the power supply output terminal BAT-OUT, so as to provide electric energy required by normal operation for an external circuit connected with the power supply output terminal BAT-OUT, so that the trigger circuit 14 can be understood as a switching circuit structure for waking up the external circuit to normally operate in a certain sense, and by designing the trigger circuit 14, the requirement of low-power-consumption switching control of the external circuit can be met, and the design cost is reduced. Therefore, when the overvoltage protection circuit 1 is in a shutdown state, the power supply circuit 12 is completely cut off from an external circuit, and the power consumption of the overvoltage protection circuit 1 is extremely low and can reach within 1uA, so that the low-power-consumption design is realized.
As shown in fig. 1, in order to enable the trigger signal to cooperate with the control signal to control the ON/off of the ON/off circuit 11, in an embodiment, the overvoltage protection circuit 1 further includes a detection signal terminal KEY-PWR, the detection signal terminal KEY-PWR is connected to the trigger circuit 14, the detection signal terminal KEY-PWR is configured to form an ON signal when the trigger signal is detected and output the ON signal to an external circuit, so that the control signal terminal PWR-ON outputs a control signal, and the second switching element D2 is further configured to limit the charging signal from the charging signal receiving terminal Vusb to the detection signal terminal KEY-PWR.
The detection signal terminal KEY-PWR is equivalent to a port of the overvoltage protection circuit 1 for detecting whether the trigger circuit 14 forms a valid trigger signal under the operation of a user, that is, the detection signal terminal KEY-PWR is used for detecting the presence or absence of the trigger signal. The detection signal end KEY-PWR forms a conducting signal when detecting the trigger signal, the detection signal end KEY-PWR transmits the conducting signal to an external circuit, the external circuit carries out corresponding processing ON the conducting signal to form the control signal, and the external circuit transmits the control signal to the control signal end PWR-ON. ON one hand, the control signal terminal PWR-ON transmits a control signal to the first switching element D1 to turn ON the first switching element D1, and when the first switching element D1 is turned ON, the ON-off circuit 11 is turned ON, and when the ON-off circuit 11 is turned ON, the power supply circuit 12 outputs a preset safe voltage + BAT to the power supply output terminal BAT-OUT, thereby ensuring normal operation of the external circuit. On the other hand, the second switch device D2 can also effectively limit the conduction of the charging signal from the charging signal receiving terminal Vusb to the detection signal terminal KEY-PWR, so that when the charging signal of the charging circuit 21 is too large due to misoperation, the design of the second switch device D2 can effectively avoid the possibility of burning out the external circuit due to the too large charging signal.
As shown in fig. 1, it is considered that in the case where the trigger circuit 14 forms a trigger signal under the operation of the user, the trigger signal has a possibility of being turned ON from the trigger circuit 14 to the charging signal receiving terminal Vusb, or in the case where the control signal output from the external circuit is received by the control signal terminal PWR-ON, the control signal has a possibility of being turned ON from the control signal terminal PWR-ON to the charging signal receiving terminal Vusb. To avoid the above two possibilities, it is designed that, in an embodiment, the overvoltage protection circuit 13 further includes a third switching element D3, the third switching element D3 is connected between the charging signal receiving terminal Vusb and the on-off circuit 11, the third switching element D3 is used for conducting the charging signal from the charging signal receiving terminal Vusb to the on-off circuit 11, the third switching element D3 is further used for limiting the trigger signal from the trigger circuit 14 to the charging signal receiving terminal Vusb, and the third switching element D3 is further used for limiting the control signal from the control signal receiving terminal to the charging signal receiving terminal Vusb.
The third switching element D3 may be a unidirectional conducting element, and the third switching element D3 is unidirectional conducting under the action of the charging signal, so that the charging signal can only be transmitted from the charging signal receiving terminal Vusb to the on-off circuit 11, and the detailed expression about the third switching element D3 will be described later.
In this design, by designing the third switching element D3, on one hand, the third switching element D3 is turned on under the effect of the charging signal, so that the charging signal can be transmitted from the charging signal receiving terminal Vusb to the on-off circuit 11 to turn on the on-off circuit 11, and the on-off circuit 11 is turned on to allow the power supply circuit 12 to output the preset safe voltage + BAT to the power supply output terminal BAT-OUT, thereby supplying power to an external circuit connected to the power supply output terminal BAT-OUT to ensure normal operation of the external circuit. ON the other hand, the third switching element D3 can effectively limit the trigger signal from the trigger circuit 14 to the charging signal receiving terminal Vusb, and can effectively limit the control signal from the control signal terminal PWR-ON to the charging signal receiving terminal Vusb.
As shown in fig. 1, the first switching element D1, the second switching element D2, and the third switching element D3 may be embodied by, but not limited to, one or more of the following embodiments, considering that the first switching element D1, the second switching element D2, and the third switching element D3 are all unidirectional conductive elements.
In one embodiment, the first switching element D1 may be one of a diode or an electrically controlled switch. When the first switching element D1 is a diode, the anode of the diode is connected to the control signal terminal PWR-ON, and the cathode of the diode is connected to the ON-off circuit 11. When the first switching element D1 is an electronic control switch, the electronic control switch is turned ON when the control signal terminal PWR-ON receives the control signal, so that the control signal can be turned ON from the control signal terminal PWR-ON to the ON-off circuit 11, and the electronic control switch is turned off when the charging signal receiving terminal Vusb receives the charging signal, so as to limit the charging signal from the charging signal receiving terminal Vusb to the control signal terminal PWR-ON.
In one embodiment, the second switching element D2 is one of a diode or an electrically controlled switch. When the second switching element D2 is a diode, the anode of the diode is connected to the trigger circuit 14, and the cathode of the diode is connected to the on-off circuit 11. When the second switch element D2 is an electrically controlled switch, the electrically controlled switch is closed when the trigger circuit 14 forms a trigger signal, so that the trigger signal can be conducted from the trigger circuit 14 to the on-off circuit 11, and the electrically controlled switch is opened when the charging signal receiving terminal Vusb receives the charging signal, so as to limit the conduction of the charging signal from the charging signal receiving terminal Vusb to the trigger circuit 14.
In one embodiment, the third switching element D3 is one of a diode or an electrically controlled switch. When the third switching element D3 is a diode, the anode of the diode is connected to the charging signal receiving terminal Vusb, and the cathode of the diode is connected to the on-off circuit 11. When the third switching element D3 is an electronic control switch, the electronic control switch is closed when the charging signal receiving terminal Vusb receives a charging signal, so that the charging signal can be turned ON from the charging signal receiving terminal Vusb to the ON-off circuit 11, the electronic control switch is opened when the control signal terminal PWR-ON receives a control signal, so as to limit the control signal from the control signal terminal PWR-ON to the charging signal receiving terminal Vusb, and the electronic control switch is also opened when the trigger circuit 14 forms a trigger signal, so as to limit the trigger signal from the trigger circuit 14 to the charging signal receiving terminal Vusb.
As shown in fig. 1, in view of that the trigger circuit 14 can form a trigger signal under the operation of a user, and the detection signal terminal KEY-PWR can form a conducting signal and transmit the conducting signal to an external circuit when detecting the trigger signal, in order to enable the trigger circuit 14 to have the above function, in an embodiment, the trigger circuit 14 includes a fourth switching element S1, a first resistor R11 and a second resistor R12, a first terminal of the fourth switching element S1 is connected to the power supply circuit 12, a second terminal of the fourth switching element S1 is connected to the second switching element D2, a first terminal of the first resistor R11 is connected to a second terminal of the fourth switching element S1, a first terminal of the second resistor R12 and a second terminal of the first resistor R11 are connected to the first node b1, a second terminal of the second resistor R12 is connected to ground, and the detection signal terminal KEY-PWR is connected to the first node b 1.
The fourth switch element S1 may be a touch switch or a key switch, for example, a single-pole single-throw switch. In the design, a user touches the fourth switching element S1, the fourth switching element S1 is closed to form a trigger signal, the trigger signal passes through the first resistor R11 and then is transmitted to the detection signal end KEY-PWR, the detection signal end KEY-PWR forms a conducting signal after detecting the trigger signal and transmits the conducting signal to an external circuit, and the external circuit processes the conducting signal and outputs a control signal to the control signal end PWR-ON. The first resistor R11 and the second resistor R12 form a voltage dividing resistor loop, and the trigger signal is reduced in voltage by the first resistor R11 and then transmitted to the detection signal end KEY-PWR, so that the possibility that the detection signal end KEY-PWR burns out an external circuit due to overlarge signals can be effectively avoided. Through the voltage division of the first resistor R11 and the second resistor R12, an external circuit such as an MCU performs voltage judgment to detect whether the fourth switching element S1 is operated, so as to implement the on/off operation of the overvoltage protection circuit 1 according to the operation time and sequence, and of course, the judgment may also be performed according to the operation frequency of the fourth switching element S1 to perform corresponding functional operations.
As shown in fig. 1 and fig. 2, in consideration of the fact that when a large charging signal is transmitted from the external power supply to the charging circuit 21 due to an erroneous operation, the large charging signal flows into the overvoltage protection circuit 1 from the charging signal receiving terminal Vusb, so that there is a possibility of burning out the power supply circuit 12, in order to avoid damage to the power supply circuit 12, the overvoltage protection circuit is designed, in some embodiments, further includes a voltage reduction circuit 15, and the voltage reduction circuit 15 is configured to connect the charging circuit 21 with the power supply circuit 12, so as to reduce the charging signal to the preset safe voltage + BAT. That is, the step-down circuit 15 is capable of stepping down a large charging signal generated by a malfunction to the preset safe voltage + BAT, and finally charging the power supply circuit 12 with the preset safe voltage + BAT. The voltage reducing circuit 15 may include a charging IC (as shown in fig. 2 as U1) with an overvoltage protection function (overvoltage protection refers to a protection mode that when the voltage of the line to be protected exceeds a predetermined maximum value, the power supply is turned off or the voltage of the controlled device is reduced), for example, a charging IC with a model number of SGM 4056-6.8ytdeigg may be selected, and a larger charging signal may be reduced to a preset safe voltage + BAT after passing through the charging IC. In this design, through design step-down circuit 15, can be effectively with the great charge signal step-down that forms under the maloperation to predetermineeing safe voltage + BAT to power supply circuit 12 plays good guard action. The design can remove an over voltage protection chip (OVP) and achieve the purpose of saving cost.
Considering that the ON-off circuit 11 is equivalent to a circuit structure for controlling the connection or disconnection between the power supply circuit 12 and the power supply output terminal BAT-OUT in the overvoltage protection circuit 1, the ON-off circuit 11 can be connected under the direct action of the control signal or the charging signal, and the ON-off circuit 11 can also be connected under the coordination action of the trigger signal and the control signal, in order to enable the ON-off circuit 11 to have the function, it is designed that in one embodiment, the ON-off circuit 11 includes a first electronic switch Q1, a second electronic switch Q2 and a third resistor R13, the first electronic switch Q1 is connected with the charging signal receiving terminal Vusb and the control signal terminal PWR-ON through the overvoltage protection circuit 13, the second electronic switch Q2 is connected with the first electronic switch Q1 in series, the second electronic switch Q2 is connected with the power supply circuit 12 and the power supply output terminal BAT-OUT, the third resistor R13 is connected with the second electronic switch Q2 in parallel, and when the charging signal receiving terminal usb receives the charging signal, the first electronic switch Q1 and the second electronic switch Q2 are connected with the power supply circuit 12 and the power supply output terminal BAT-OUT through the second electronic switch Q2. Certainly, when the control signal terminal PWR-ON receives the control signal, the first electronic switch Q1 and the second electronic switch Q2 are turned ON, and the power supply circuit 12 outputs the preset safe voltage + BAT to the power supply output terminal BAT-OUT through the second electronic switch Q2. When the trigger circuit 14 forms a trigger signal under the touch operation of a user, the detection signal terminal KEY-PWR detects the trigger signal and forms a conduction signal to be transmitted to an external circuit, the external circuit converts the conduction signal into a detection signal to be transmitted to the control signal terminal PWR-ON, the first electronic switch Q1 and the second electronic switch Q2 are turned ON, and the power supply circuit 12 outputs a preset safe voltage + BAT to the power supply output terminal BAT-OUT through the second electronic switch Q2.
The first electronic switch Q1 and the second electronic switch Q2 may be embodied in one or more of the following embodiments.
In one embodiment, the first electronic switch Q1 is one of a triode or a field effect transistor. When the first electronic switch Q1 is a triode, the triode may be a PNP type triode or an NPN type triode. When the first electronic switch Q1 is a field effect transistor, the field effect transistor may be a PMOS type field effect transistor or an NMOS type field effect transistor.
In one embodiment, the second electronic switch Q2 is a field effect transistor. When the second electronic switch Q2 is a fet, the fet may be a PMOS fet or an NMOS fet.
Specifically, when the first electronic switch Q1 is an NPN-type triode and the second electronic switch Q2 is a PMOS-type field effect transistor, an emitter of the triode is grounded, a base of the triode is connected with the overvoltage protection circuit 13, a collector of the triode is connected with a gate of the field effect transistor, a source of the field effect transistor is connected with the power supply circuit 12, and a drain of the field effect transistor is connected with the power supply output terminal BAT-OUT.
During charging, the charging signal receiving end Vusb receives a charging signal, the charging signal acts on the base electrode of the triode to enable the collector electrode and the emitter electrode of the triode to be conducted, the emitter electrode of the triode is grounded to pull down the grid electrode of the field effect transistor to enable the source electrode and the drain electrode of the field effect transistor to be conducted, the power supply circuit 12 outputs preset safe voltage + BAT to the power supply output end BAT-OUT, and the external circuit receives the preset safe voltage + BAT and starts to work. It should be noted that, because of the existence of the overvoltage protection circuit 13, even if the voltage of the charging signal is increased to 20V or more, the power supply circuit 12 can be ensured to be completely isolated from the charging signal receiving terminal Vusb, and the external circuit will not be permanently damaged due to the overhigh voltage of the charging signal.
When the battery is not charged, the charging signal is not input into the charging signal receiving end Vusb, the triode and the field effect transistor are both in the off state, so that the power supply circuit 12 is disconnected with the power supply output end BAT _ OUT, the external circuit and the overvoltage protection circuit are cut off, and the static power consumption of the external circuit is within 1 uA. The user can operate the fourth switching element S1 to wake up and supply power to the external circuit. In an application environment, the fourth switching element S1 is turned ON and forms a trigger signal under the operation of a user, the detection signal terminal KEY-PWR detects the trigger signal and then forms a conduction signal and transmits the conduction signal to an external circuit, the external circuit performs corresponding processing ON the conduction signal to form the control signal, the external circuit transmits the control signal to the control signal terminal PWR-ON, the control signal terminal PWR-ON transmits the control signal to the diode to turn ON the diode, the diode is turned ON to turn ON the triode, the emitter of the triode is grounded to pull down the gate of the field effect transistor to turn ON the source and the drain of the field effect transistor, the power supply circuit 12 outputs a preset safe voltage + BAT to the power supply output terminal BAT-OUT, and the external circuit receives the preset safe voltage + BAT and starts to work.
It should be noted that the control signal terminal PWR _ ON can continuously output the control signal through the control of the external circuit (e.g., MUC), which is enough to continuously turn ON the transistor and the fet, so that the power supply circuit 12 continuously outputs the preset safe voltage + BAT to the power supply output terminal BAT-OUT, thereby ensuring the normal operation of the external circuit. In the same way, the power supply circuit 12 can stop outputting the preset safe voltage + BAT to the power supply output terminal BAT-OUT by turning off the triode and the field effect transistor, so that the power-off shutdown of the external circuit is realized, after the external circuit is powered off and shutdown, the charging voltage can be accessed through the charging signal receiving terminal Vusb or the fourth switching element S1 is operated to be switched on to form the trigger signal to switch on the triode and the field effect transistor, and the power supply circuit 12 outputs the preset safe voltage + BAT to the power supply output terminal BAT-OUT, so that the normal work of the external circuit is ensured. Due to the existence of the overvoltage protection circuit 13, the trigger signal does not affect the circuits at the two positions of the charging signal receiving terminal Vusb and the control signal terminal PWR-ON.
As shown in fig. 1 and fig. 3, in order to determine whether the charging circuit 21 is effectively connected to the external power source, so that the charging signal receiving terminal Vusb outputs an effective charging signal, in some embodiments, the overvoltage protection circuit 1 further includes a charging determination circuit 16, the charging determination circuit 16 is connected to the charging signal receiving terminal Vusb, and the charging determination circuit 16 is configured to detect whether the charging signal receiving terminal Vusb is connected to the charging signal.
As an example, the charging determination circuit 16 includes a determination signal output terminal USB-CHGIN, a fourth resistor R14, a third electronic switch Q3, and a fifth resistor R15, a first end of the fourth resistor R14 is connected to the charging signal receiving terminal Vusb, a control terminal of the third electronic switch Q3 is connected to a second end of the fourth resistor R14, a first connection terminal of the third electronic switch Q3 is grounded, a first end of the fifth resistor R15 is configured to be connected to the reference voltage VCC, a second end of the fifth resistor R15 and a second connection terminal of the third electronic switch Q3 are connected to a second node b2, and the second node b2 is connected to the determination signal output terminal USB-CHGIN.
Illustratively, the third electronic switch Q3 is an NPN-type transistor, a base of the transistor is connected to the second end of the fourth resistor R14 as the control terminal, an emitter of the transistor is grounded as the first connection terminal, and a collector of the transistor is connected to the second node b2 as the second connection terminal and a second end of the fifth resistor R15. The "reference voltage VCC" may be understood as a voltage outputted from the determination signal output terminal USB-CHGIN when the charging circuit 21 is not effectively connected to the external power supply, and the determination signal output terminal USB-CHGIN may be connected to the control pin of the charging IC, so as to transmit a high level signal corresponding to the reference voltage VCC to the charging IC.
When the charging circuit 21 is connected to the charging signal receiving terminal Vusb, the charging signal acts on the base electrode of the triode through the fourth resistor R14 to conduct the collector electrode of the triode with the emitter electrode of the triode, and since the emitter electrode of the triode is grounded, the voltage of the collector electrode of the triode is pulled down to form a low level signal and the low level signal is transmitted to the determination signal output terminal USB-CHGIN, and the determination signal output terminal USB-CHGIN can be connected with the control pin of the charging IC to transmit the low level signal to the charging IC. By designing the fourth resistor R14, the third electronic switch Q3 can be well protected against a large charging signal due to an erroneous operation.
A second aspect of the present application provides a power supply system, which includes a charging circuit 21 and the above-mentioned overvoltage protection circuit 1, where the charging circuit 21 is connected to the charging signal receiving terminal Vusb to provide a charging signal to the charging signal receiving terminal Vusb. In the design, the power supply system with the overvoltage protection circuit 1 can effectively avoid the possibility of burning out an external circuit due to overlarge charging voltage caused by overvoltage.
A third aspect of the present application provides an electronic device, which includes a charging circuit 21 and the above power supply system, and the power supply system is disposed in the housing. The electronic device may be, but not limited to, an electronic product that needs to be charged and discharged, such as a massager (e.g., a wearable or physiotherapy instrument for the neck, waist, abdomen, or wrist). In the design, the electronic equipment with the power supply system can effectively avoid the possibility of burning out an external circuit due to overlarge charging voltage caused by overvoltage.
The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present application, it is to be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. 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 intended to indicate or imply that the referred device or element 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 only for illustrative purposes and are not to be construed as limitations of the present patent, and specific meanings of the above terms may be understood by those skilled in the art according to specific situations.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (14)
1. An overvoltage protection circuit, characterized in that the overvoltage protection circuit comprises: the charging circuit comprises a charging signal receiving end, an on-off circuit, a power supply circuit, an overvoltage preventing circuit, a control signal end and a power supply output end;
the charging signal receiving end is connected with the charging circuit to receive a charging signal, and the charging signal receiving end is connected with the on-off circuit to conduct the on-off circuit when receiving the charging signal;
the power supply circuit is sequentially connected with the on-off circuit and the power supply output end so as to output a preset safe voltage to the power supply output end when the on-off circuit is conducted;
the control signal end is used for being connected with an external circuit to receive a control signal;
the overvoltage protection circuit is connected between the control signal end and the on-off circuit and used for limiting the conduction of the charging signal from the charging signal receiving end to the control signal end, and the overvoltage protection circuit is also connected between the charging signal receiving end and the on-off circuit and used for limiting the conduction of the control signal from the control signal end to the charging signal receiving end.
2. The circuit according to claim 1, wherein the overvoltage protection circuit comprises a first switch element, the first switch element is connected between the control signal terminal and the on-off circuit, the control signal terminal is configured to input the control signal to the on-off circuit to turn on the on-off circuit, and the first switch element is configured to turn on the control signal from the control signal terminal to the on-off circuit and to limit the conduction of the charging signal from the charging signal receiving terminal to the control signal terminal.
3. The circuit according to claim 2, further comprising a trigger circuit, wherein the trigger circuit is connected to the power supply circuit, and further comprising a second switch element, wherein the second switch element is connected between the trigger circuit and the on-off circuit, and the second switch element is configured to enable the trigger signal of the trigger circuit to be conducted from the trigger circuit to the on-off circuit, and to limit the charging signal from the charging signal receiving terminal to be conducted to the trigger circuit.
4. The overvoltage protection circuit of claim 3,
the overvoltage protection circuit further comprises a detection signal end, the detection signal end is connected with the trigger circuit and used for forming a conduction signal when the trigger signal is detected and outputting the conduction signal to the external circuit, so that the control signal end outputs the control signal, and the second switch element is further used for limiting the conduction of the charging signal from the charging signal receiving end to the detection signal end.
5. The circuit of claim 4, further comprising a third switch element, wherein the third switch element is connected between the charging signal receiving terminal and the on-off circuit, and the third switch element is used for enabling the charging signal to be conducted from the charging signal receiving terminal to the on-off circuit, limiting the triggering signal to be conducted from the triggering circuit to the charging signal receiving terminal, and limiting the control signal to be conducted from the control signal terminal to the charging signal receiving terminal.
6. The overvoltage protection circuit of claim 5,
the first switch element is one of a diode or an electric control switch; and/or
The second switch element is one of a diode or an electric control switch; and/or
The third switch element is one of a diode or an electrically controlled switch.
7. The overvoltage protection circuit of claim 5, wherein the trigger circuit comprises:
a fourth switching element, a first end of which is connected to the power supply circuit and a second end of which is connected to the second switching element;
a first resistor, a first end of the first resistor being connected to a second end of the fourth switching element; and
and a first end of the second resistor and a second end of the first resistor are connected to a first node, a second end of the second resistor is grounded, and the detection signal end is connected with the first node.
8. The protection circuit of any one of claims 1-7, further comprising a voltage dropping circuit for connecting the charging circuit with the power supply circuit for dropping the charging signal to the preset safe voltage.
9. The overvoltage protection circuit according to any one of claims 1-7, wherein the switching circuit comprises:
the first electronic switch is connected with the charging signal receiving end and the control signal end through the overvoltage preventing circuit;
the second electronic switch is connected with the first electronic switch in series and is connected between the power supply circuit and the power supply output end;
a third resistor connected in parallel with the second electronic switch;
when the charging signal receiving end receives the charging signal, the first electronic switch and the second electronic switch are switched on, and the power supply circuit outputs the preset safe voltage to the power supply output end through the second electronic switch.
10. The overvoltage protection circuit of claim 9,
the first electronic switch is one of a triode or a field effect transistor, and/or
The second electronic switch is a field effect transistor.
11. The circuit of any one of claims 1-7,
the overvoltage protection circuit also comprises a charging judgment circuit, the charging judgment circuit is connected with the charging signal receiving end, and the charging judgment circuit is used for detecting the charging signal.
12. The overvoltage protection circuit according to claim 11, wherein the charge determination circuit comprises:
a decision signal output terminal;
a first end of the fourth resistor is connected with the charging signal receiving end;
a control end of the third electronic switch is connected with a second end of the fourth resistor, and a first connecting end of the third electronic switch is grounded;
and a first end of the fifth resistor is used for accessing a reference voltage, a second end of the fifth resistor and a second connecting end of the third electronic switch are connected to a second node, and the second node is connected with the judgment signal output end.
13. A power supply system, comprising:
the overvoltage protection circuit of any one of claims 1-12; and
and the charging circuit is connected with the charging signal receiving end to provide the charging signal for the charging signal receiving end.
14. An electronic device, comprising:
a housing; and
the power supply system of claim 13, said power supply system being disposed in said housing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221185414.2U CN217769460U (en) | 2022-05-17 | 2022-05-17 | Overvoltage protection circuit, power supply system and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221185414.2U CN217769460U (en) | 2022-05-17 | 2022-05-17 | Overvoltage protection circuit, power supply system and electronic equipment |
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| Publication Number | Publication Date |
|---|---|
| CN217769460U true CN217769460U (en) | 2022-11-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202221185414.2U Active CN217769460U (en) | 2022-05-17 | 2022-05-17 | Overvoltage protection circuit, power supply system and electronic equipment |
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| Country | Link |
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| CN (1) | CN217769460U (en) |
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