CN212137267U

CN212137267U - Overvoltage protection circuit and electronic equipment

Info

Publication number: CN212137267U
Application number: CN202020883719.5U
Authority: CN
Inventors: 尤长原
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2020-12-11
Anticipated expiration: 2030-05-22

Abstract

The utility model relates to an overvoltage crowbar and electronic equipment, the circuit includes: the overvoltage protection controller is used for outputting a control signal according to a comparison result of the input voltage and the reference voltage; and the switch component is independent of the overvoltage protection controller, is connected with the overvoltage protection controller, and is used for conducting and outputting voltage under the control of the control signal, or disconnecting and stopping voltage output under the control of the control signal.

Description

Overvoltage protection circuit and electronic equipment

Technical Field

The utility model relates to an electronic equipment technical field especially relates to an overvoltage crowbar and electronic equipment.

Background

In order to meet the charging requirement of the mobile phone terminal, a Universal charging interface is configured on the mobile phone terminal, and different charging devices adopt unified similar interfaces, for example, an android mobile phone adopts a unified Micro Universal Serial Bus (Micro USB, Micro Universal Serial Bus) or a USB interface of type c (type c).

Meanwhile, the charging environment becomes very complicated, for example, common chargers such as a car charger, a solar charger, a wall charger, and the like, and the mobile phone terminal is designed to be charged using different chargers. Different chargers may have different output voltages, and the mobile phone terminal may damage a Power Management Unit (PMU) or a charging Integrated Circuit Chip (IC) due to an input of an excessive voltage.

Disclosure of Invention

In view of this, the utility model provides an overvoltage crowbar and electronic equipment.

According to the utility model discloses an aspect provides an overvoltage protection circuit, include:

the overvoltage protection controller is used for outputting a control signal according to a comparison result of the input voltage and the reference voltage;

and the switch component is independent of the overvoltage protection controller, is connected with the overvoltage protection controller, and is used for conducting and outputting voltage under the control of the control signal, or disconnecting and stopping voltage output under the control of the control signal.

In one embodiment, the circuit further comprises: a power input terminal for connecting with an input power source, a power output terminal for outputting a voltage, and a voltage stabilizing assembly, wherein,

the voltage stabilizing component is used for generating the reference voltage;

the overvoltage protection controller is respectively connected with the power supply input end and the voltage stabilizing assembly;

the switch assembly is connected between the power input end and the power output end.

In one embodiment, the voltage regulation assembly comprises: a first resistor and a voltage stabilizing element, wherein,

the first resistor and the voltage stabilizing element are sequentially connected in series between the power supply input end and a reference ground; the voltage stabilizing element is applied with the voltage under the action of the input voltage as the reference voltage.

In one embodiment, the voltage stabilization component includes: and a voltage regulator diode.

In one embodiment, the overvoltage protection controller comprises:

a second resistor, a third resistor, and a first switching element, wherein,

the control end of the first switching element is connected with the voltage stabilizing component through the second resistor connected in series to receive the reference voltage;

the input end of the first switching element is connected with the power supply input end;

the output end of the first switching element is connected with the reference ground through a third resistor;

the first switch element is configured to turn on an input terminal of the first switch element and an output terminal of the first switch element according to a comparison result between the input voltage at the power input terminal and the reference voltage, and output a first control sub-signal; or disconnecting the input end of the first switch element and the output end of the first switch element and outputting a second control sub-signal; wherein the first control sub-signal turns off the switching component; the second control sub-signal turns on the switch component.

In one embodiment, the first switching element includes: a PNP triode;

wherein,

the base electrode of the PNP triode is the control end of the first switching element;

the emitter of the PNP triode is the input end of the first switching element;

the collector of the PNP triode is the output end of the first switching element.

In one embodiment, the switch assembly comprises: a second switching element, wherein,

the input end of the second switching element is connected with the power supply input end;

the output end of the second switch element is connected with the power supply output end and used for outputting voltage;

the control end of the second switch element is connected with the overvoltage protection controller, and the input end of the second switch element and the output end of the second switch element are disconnected in response to receiving a first control sub-signal, or the input end of the second switch element and the output end of the second switch element are connected in response to receiving a second control sub-signal.

In one embodiment, the second switching element includes: a P-channel field effect transistor;

the source electrode of the P-channel field effect transistor is the input end of the second switching element;

the drain electrode of the P-channel field effect transistor is the output end of the second switching element;

and the grid electrode of the P-channel field effect transistor is the control end of the second switching element.

In one embodiment, the circuit further comprises: a fourth resistance, which is a resistance of the fourth resistor,

and the drain electrode of the P-channel field effect transistor is connected with the reference ground through the fourth resistor, and the fourth resistor is used for releasing the electric energy stored by the parasitic capacitor between the drain electrode and the grid electrode.

According to a second aspect of the embodiments of the present invention, there is provided an electronic apparatus, wherein the electronic apparatus includes: a load circuit and the overvoltage protection circuit of the first aspect; the load circuit is connected with the overvoltage protection circuit and receives the voltage output by the overvoltage protection circuit.

In one embodiment, the electronic device includes: a transient voltage suppressor; wherein,

the transient voltage suppressor is arranged between an input power supply and the overvoltage protection circuit and is connected with a reference ground.

The embodiment of the utility model provides an overvoltage crowbar and electronic equipment, overvoltage crowbar includes: the overvoltage protection controller is used for outputting a control signal according to a comparison result of the input voltage and the reference voltage; and the switch component is independent of the overvoltage protection controller, is connected with the overvoltage protection controller, and is used for conducting and outputting voltage under the control of the control signal, or disconnecting and stopping voltage output under the control of the control signal. On one hand, the overvoltage protection controller controls the on and off of the switch component based on the reference voltage, and the accuracy of overvoltage protection is improved. On the other hand, the switch assembly is independent of the overvoltage protection controller, so that the flexibility of selecting the switch assembly can be improved, the switch assembly suitable for the current application scene can be selected according to different requirements, and the adaptability of the switch assembly to the application scene is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of embodiments of the invention.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic diagram of a related art overvoltage protection circuit;

FIG. 2 is a schematic diagram of an exemplary configuration of an overvoltage protection circuit component in accordance with an exemplary embodiment;

FIG. 3 is a schematic diagram of another overvoltage protection circuit configuration shown in accordance with an exemplary embodiment;

FIG. 4 is a schematic diagram of another alternative configuration of an overvoltage protection circuit in accordance with an exemplary embodiment;

FIG. 5 is a schematic diagram of yet another alternative configuration of an overvoltage protection circuit, according to an exemplary embodiment;

FIG. 6 is a schematic diagram of yet another alternative configuration of an overvoltage protection circuit, according to an exemplary embodiment;

FIG. 7 is a schematic diagram of yet another alternative configuration of an overvoltage protection circuit in accordance with an exemplary embodiment;

FIG. 8 is a schematic diagram illustrating an electronic device component structure in accordance with an exemplary embodiment;

FIG. 9 is a schematic diagram illustrating another electronic device component configuration in accordance with an exemplary embodiment;

fig. 10 is a timing diagram illustrating overvoltage protection triggering according to an exemplary embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

Therefore, an integrated Over Voltage Protection (OVP) circuit is added to the mobile phone terminal, but the integrated OVP circuit has a large on-resistance, the response time is easily affected by peripheral circuits, and the cost is high.

An integrated OVP overvoltage protection circuit adopted by a mobile phone terminal is shown in figure 1, and the overvoltage protection circuit is composed of an OVP IC U5400 and peripheral capacitors and resistors. The voltage value of OVP IC overvoltage protection can be set through the divider resistors R5401, R5402 and R5404, and meanwhile, the voltage stability of the whole charging loop and the reduction of power supply noise are guaranteed through the peripheral capacitors C5415, C5418, C5419, C5412 and C5433.

The integrated OVP IC has a large on-resistance and the peripheral capacitance affects the response time of the OVP IC, resulting in a long response time of the OVP.

Fig. 2 is a block diagram illustrating an overvoltage protection circuit 100 in accordance with an exemplary embodiment. Referring to fig. 2, the overvoltage protection circuit 100 includes, but is not limited to:

an overvoltage protection controller 110 for outputting a control signal according to a comparison result of the input voltage and the reference voltage;

and a switch component 120, independent of the overvoltage protection controller 110, connected to the overvoltage protection controller 110, and configured to turn on and output a voltage under the control of the control signal, or turn off and stop the voltage output under the control of the control signal.

Here, the overvoltage protection circuit 100 can be applied to electronic devices such as a mobile phone terminal. The overvoltage protection circuit 100 provides overvoltage protection for a flashlight electronic device from power supplied from an input power source, such as a charger or a power adapter, within the electronic device.

The overvoltage protection circuit 100 may be connected to a power interface of an electronic device, and an input power may supply power to an internal circuit such as a PMU or a charging IC in the electronic device through the overvoltage protection circuit 100.

The input voltage may be a voltage input to the electronic device by the input power source. The reference voltage may be set according to a voltage that the internal circuit of the electronic device can withstand, for example, the reference voltage may be set to be lower than the voltage that the internal circuit of the electronic device can withstand.

The overvoltage protection controller 110 can be implemented using a voltage comparator, a processing chip with a digital/analog (a/D) conversion function, or a discrete component. By comparing the input voltage with the reference voltage, the output control signal controls the switch element 120 to output the voltage or stop outputting the voltage.

For example, the overvoltage protection controller 110 may compare the input voltage with a reference voltage, output a control signal to control the switching element 120 to output the voltage when the input voltage is less than or equal to the reference voltage, and output the control signal to control the switching element 120 to stop outputting the voltage when the input voltage is greater than the reference voltage; it is also possible to set a voltage threshold, and when the input voltage is greater than the reference voltage and the difference between the input voltage and the reference voltage is less than or equal to the voltage threshold, the output control signal controls the switching component 120 to output the voltage, and when the input voltage is greater than the reference voltage and the difference between the input voltage and the reference voltage is greater than the voltage threshold, the output control signal controls the switching component 120 to stop outputting the voltage.

The switching component 120 can be a discrete component or an integrated switching circuit or the like that is independent of the overvoltage protection controller 110. The selection of switching elements 120 with different on-resistances, and/or different on-response times, and/or different off-times may be based on the actual requirements of the electronic circuitry within the electronic device.

For example, the switch component 120 with smaller on-resistance may be selected, so as to reduce the voltage drop at the switch component 120, thereby reducing the power consumption at the switch component 120 and improving the power supply efficiency of the electronic device.

Thus, on one hand, the overvoltage protection controller 110 controls the switch component 120 to be turned on and off based on the reference voltage, so as to improve the accuracy of the overvoltage protection. On the other hand, the switch component 120 is independent of the overvoltage protection controller 110, so that the flexibility of selecting the switch component 120 can be improved, the switch component 120 suitable for the current application scenario can be selected according to different requirements, and the adaptability of the switch component 120 to the application scenario is improved.

In one embodiment, as shown in fig. 3, the circuit further comprises: a power input 130 for connection to an input power source, a power output 140 for outputting a voltage, and a voltage regulation component 150, wherein,

the voltage stabilizing component 150 is used for generating the reference voltage;

the overvoltage protection controller 110 is respectively connected to the power input terminal 130 and the voltage stabilizing component 150;

the switch assembly 120 is connected between the power input 130 and the power output 140.

Here, the power input terminal 130 may be an interface for connecting an electronic device to an input power, or may be a line on a circuit board or a pin of an electronic component. The input power is coupled to the overvoltage protection circuit 100 through a power input 130.

The power output 140 may be a line on a circuit board or a pin of an electronic component, and the overvoltage protection circuit 100 outputs a voltage to an internal circuit of the electronic device through the power output 140.

The voltage regulator 150 may be connected to the power input 130 to generate a reference voltage by supplying power from an input power source. The voltage regulation component 150 may be a wide input voltage device that can accommodate different input voltages.

For example, the voltage regulator component 150 may be implemented by a Low dropout regulator (LDO) or the like, and the LDO may provide a constant reference voltage lower than the voltage of the input power source.

The overvoltage protection controller 110 may be connected to the power input terminal 130 and the voltage regulator module 150, receive an input voltage of the input power and a reference voltage generated by the voltage regulator module 150, and generate a control signal by comparing the input voltage and the reference voltage.

In one embodiment, as shown in fig. 4, the voltage stabilizing assembly 150 includes: a first resistor 151, and a voltage stabilizing element 152, wherein,

the first resistor 151 and the voltage stabilizing element 152 are sequentially connected in series between the power input terminal 130 and the reference ground; the voltage applied by the voltage stabilizing element 152 according to the input voltage is the reference voltage.

Here, the first resistor 151 may function as a current limit, and the voltage stabilizing element 152 may generate a reference voltage based on the input voltage.

The voltage stabilizing element 152 may generate a reference voltage based on the voltage applied to the voltage stabilizing element 152.

For example, the voltage stabilizing element 152 may be a voltage dividing resistor, and the overvoltage protection controller 110 may estimate the voltage value of the input voltage by comparing the input voltage with the voltage across the voltage dividing resistor, i.e., the voltage difference across the first resistor 151, to generate the control signal.

In one embodiment, the voltage stabilizing element 152 includes: and a voltage regulator diode.

When the input power voltage is higher than the stabilized voltage of the zener diode, the zener diode is broken down by the reverse voltage, and at this time, the current flowing through the zener diode is sharply increased, and the output voltage of the zener diode is the nominal stabilized voltage of the zener diode, that is, the reference voltage. The first resistor 151 is a current limiting resistor of the zener diode, and can enable the zener diode to enter a voltage stabilizing state.

For example, for an electronic device such as a mobile phone terminal, a zener diode with a nominal regulated voltage of 5.1V may be selected, and the first resistor 151 of 10K ohms may be selected.

In one embodiment, as shown in fig. 5, the overvoltage protection controller 110 includes:

a second resistor 111, a third resistor 112, and a first switching element 113, wherein,

the control end of the first switch element 113 is connected to the voltage stabilizing component 150 through the second resistor 111 connected in series, and receives the reference voltage;

the input terminal of the first switching element 113 is connected to the power input terminal 130;

the output terminal of the first switching element 113 is connected to the reference ground through a third resistor 112;

the first switch element 113 is configured to, according to a comparison result between the input voltage of the power input terminal 130 and the reference voltage, turn on an input terminal of the first switch element 113 and an output terminal of the first switch element 113, and output a first control sub-signal; or disconnect the input terminal of the first switching element 113 and the output terminal of the first switching element 113 and output a second control sub-signal; wherein the first control sub-signal turns off the switching component 120; the second control sub-signal turns on the switch element 120.

Here, the second resistor 111 may be used to limit the current of the control terminal;

the first switching element 113 may turn on an input terminal of the first switching element 113 and an output terminal of the first switching element 113 when a difference between the input voltage and the reference voltage is greater than a voltage threshold. As shown in fig. 5, when the input terminal of the first switching element 113 and the output terminal of the first switching element 113 are turned on, the first control sub-signal equal to the same voltage value as the input voltage is generated at the output terminal of the first switching element 113 due to the presence of the third resistor 112. At this time, the sum of the reference voltage and the voltage threshold is an overvoltage protection voltage value of the overvoltage protection, that is, when the input voltage is greater than the overvoltage protection voltage value, the overvoltage protection circuit cuts off the input of the input voltage.

When the input terminal of the first switching element 113 and the output terminal of the first switching element 113 are turned off, a second control sub-signal having the same voltage value as the reference ground is generated at the output terminal of the first switching element 113 because no current of the third resistor 112 flows.

The first control sub-signal and the second control sub-signal have different signal states, for example, the first control sub-signal may be a high level signal, and the second control sub-signal may be a low level signal, so that the first control sub-signal and the second control sub-signal can be respectively used for controlling the off state and the on state of the switch component 120.

In one embodiment, as shown in fig. 6, the first switching element 113 includes: a PNP transistor 1131; wherein,

the base of the PNP transistor 1131 is the control terminal of the first switching element 113; the emitter of the PNP transistor 1131 is the input of the first switching element 113; the collector of the PNP transistor 1131 serves as the output terminal of the first switching element 113.

According to the characteristic of the PNP transistor 1131, when the difference between the emitter voltage and the base voltage is greater than the junction voltage of the PNP transistor 1131be, the PNP transistor 1131 can be in a saturation conducting state, and due to the existence of the third resistor 112, a high level is generated at the collector, that is, the first control sub-signal is output. That is, when the difference between the input voltage and the reference voltage is greater than the sum of the junction voltages of the PNP transistor 1131be, the first control sub-signal is output. The sum of the reference voltage and the junction voltage of the PNP triode 1131be is the overvoltage protection voltage value.

When the difference between the emitter voltage and the base voltage is less than or equal to the junction voltage of the PNP transistor 1131be, the characteristic of the PNP transistor 1131 may be in an off state, and since the collector is grounded through the third resistor 112, a low level is generated at the collector. That is, when the difference between the input voltage and the reference voltage is less than or equal to the sum of the junction voltages of the PNP transistor 1131be, the second control sub-signal is output.

The PNP transistor 1131 has a turn-on and turn-off time on the order of nanoseconds, that is, the response time of the PNP transistor 1131 for generating the control signal for different input voltages is on the order of nanoseconds. And the generation time of the control signal realized by an integrated circuit or the like is generally in the order of microseconds.

Therefore, the conduction characteristic of the PNP triode 1131 is utilized, the control signal is generated based on the input voltage and the reference voltage, the generation speed of the control signal is improved, the time delay of the control signal generated by adopting the integrated circuit is reduced, and the response speed of overvoltage protection is further improved.

In one embodiment, the switch assembly 120 includes: a second switching element, wherein,

the input terminal of the second switching element is connected to the power input terminal 130;

the output end of the second switching element is connected with the power output end 140 for outputting voltage;

the control terminal of the second switch element is connected to the overvoltage protection controller 110, and in response to receiving the first control sub-signal, the input terminal of the second switch element and the output terminal of the second switch element are disconnected, or in response to receiving the second control sub-signal, the input terminal of the second switch element and the output terminal of the second switch element are connected.

The second switching element may be implemented by an application specific integrated circuit, may be implemented by a discrete electronic element, may be implemented by a relay, or the like. The second switching element may disconnect an input terminal of the second switching element from an output terminal of the second switching element based on the control of the first control sub-signal, that is, disconnect the input voltage to protect electronic circuits of the electronic device when the input voltage is higher than the overvoltage protection voltage value. The second switch element can also conduct the input end of the second switch element and the output end of the second switch element based on the control of the second control sub-signal, namely, when the input voltage is not higher than the overvoltage protection voltage value, the input voltage is conducted, so that the electronic equipment obtains the input power supply.

In one embodiment, as shown in fig. 7, the second switching element includes: a P-channel field effect transistor 121;

the source of the P-channel fet 121 is the input of the second switching element;

the drain of the P-channel fet 121 is the output of the second switching element;

the gate of the P-channel fet 121 is the control terminal of the second switching element.

When the difference between the input voltage and the reference voltage is greater than the sum of the junction voltages of the PNP transistor 1131be, the PNP transistor 1131 may be in saturation conduction, and a high level is generated at the collector, so that the P-channel fet 121 is turned off, i.e., the input voltage is cut off when the input voltage is higher than the overvoltage protection voltage value. And overvoltage protection is realized. The sum of the reference voltage and the junction voltage of the PNP triode 1131be is the overvoltage protection voltage value.

When the difference between the emitter voltage and the base voltage is less than or equal to the junction voltage of the PNP transistor 1131be, the PNP transistor 1131 may be in a cut-off state, and a low level is generated at the collector, so that the P-channel fet 121 is turned on, i.e., when the input voltage is higher than the overvoltage protection voltage value, the input voltage is turned on.

The P-channel fet 121 has a smaller on-resistance and a shorter on/off response time, and therefore, on the one hand, using the P-channel fet 121 as a second switching element can reduce power consumption generated in the P-channel fet 121 when the P-channel fet 121 is turned on, and reduce heat generated due to current flowing through a higher on-resistance; on the other hand, the P-channel field effect transistor 121 is adopted, so that the on/off response time is improved, and the overvoltage protection response speed is further improved.

In one embodiment, as shown in fig. 7, the circuit further comprises: the fourth resistance 160 is a resistance that is,

the drain of the P-channel fet 121 is connected to ground via the fourth resistor 160, and the fourth resistor 160 is configured to discharge the electric energy stored in the parasitic capacitance between the drain and the gate.

Parasitic capacitance exists between the drain and the gate of the P-channel fet 121, and the electronic circuit behind the overvoltage protection circuit 100 can still be discharged after the P-channel fet 121 is turned off, so that the electronic circuit is in an unstable state. The fourth resistor 160 may discharge the energy stored in the parasitic capacitor, thereby reducing the instability of the electronic circuit.

The overvoltage protection circuit provided by the embodiment adopts discrete components to realize overvoltage protection, and on one hand, peripheral components on the periphery of an integrated circuit can be reduced when the integrated circuit is adopted to realize overvoltage protection, so that the cost of the peripheral components is reduced. On the other hand, the overvoltage protection is realized by adopting simple discrete components, and the cost of components can be reduced by adopting an integrated circuit relatively.

FIG. 8 is a block diagram illustrating one type of electronic device 10 according to an example embodiment. Referring to fig. 8, the electronic device 10 includes: a load circuit 200 and an overvoltage protection circuit 100; the load circuit 200 is connected to the overvoltage protection circuit 100, and receives the voltage output by the overvoltage protection circuit 100. Referring to fig. 2, the overvoltage protection circuit 100 includes, but is not limited to:

the first switching element 113 may turn on an input terminal of the first switching element 113 and an output terminal of the first switching element 113 when a difference between the input voltage and the reference voltage is greater than a voltage threshold.

As shown in fig. 5, when the input terminal of the first switching element 113 and the output terminal of the first switching element 113 are turned on, the first control sub-signal equal to the same voltage value as the input voltage is generated at the output terminal of the first switching element 113 due to the presence of the third resistor 112. When the input terminal of the first switching element 113 and the output terminal of the first switching element 113 are turned off, a second control sub-signal having the same voltage value as the reference ground is generated at the output terminal of the first switching element 113 because no current of the third resistor 112 flows. At this time, the sum of the reference voltage and the voltage threshold is an overvoltage protection voltage value of the overvoltage protection, that is, when the input voltage is greater than the overvoltage protection voltage value, the overvoltage protection circuit cuts off the input of the input voltage.

In one embodiment, as illustrated in fig. 9, the electronic device includes: a transient voltage suppressor 300; wherein,

the transient voltage suppressor 300 is disposed between the input power source 20 and the overvoltage protection circuit 100, and is connected to a reference ground.

The electronic components of the overvoltage protection circuit 100 also have a certain pressure-bearing capacity, and when the pressure-bearing capacity is exceeded, the overvoltage protection circuit 100 is damaged, so that the transient voltage suppressor 300 can be arranged between the input power supply 20 and the overvoltage protection circuit 100, and voltage sudden changes such as high voltage surge generated by the input power supply 20 are reduced.

The TVS 300 may be a Transient Voltage Suppressor (TVS), which may be used for suppressing Transient high Voltage surges, and may be connected in parallel with the overvoltage protection circuit 100. Under normal working condition, TVS presents high impedance state to the protected circuit, when the instantaneous voltage exceeds its breakdown voltage, TVS provides a low impedance path for instantaneous current. So that the transient current flowing to the overvoltage protection circuit 100 is shunted to the TVS diode, and the voltage across the overvoltage protection circuit 100 is limited to the clamped voltage across the TVS. When this overvoltage condition disappears, the TVS diode will again return to the high impedance state.

One specific example is provided below in connection with any of the embodiments described above:

as shown in fig. 7, the overvoltage protection circuit is composed of discrete components: PMOS transistor 121, zener diode 152, PNP triode 1131, and four resistors. Wherein, the resistance 151 is 10K ohm, the resistance 111 is 10K ohm, the resistance 112 is 10K ohm, the resistance 160 is 10K ohm, and the voltage stabilizing diode 152 has a nominal stable Voltage (VZ) of 5.1V.

The input voltage is introduced from the source electrode of the left PMOS tube 121, the drain electrode of the PMOS tube 121 is used for outputting voltage, and the drain electrode can be connected with a rear-end charging IC and the like. It can be seen from the circuit that the zener diode 152VZ determines the operating voltage range, and when the input voltage exceeds the sum of the zener diode 152VZ and the PNP transistor 1131be junction voltage, the PMOS transistor 121 will turn off, thereby protecting the back-end charging IC and PMU, etc. The high-precision zener diode 152 can be used to generate the reference voltage, so that the input voltage turn-off points can be concentrated and can be completely turned off within the range of 1V.

The main technical indexes of the discrete OVP circuit are as follows:

1) the protection voltage is mainly determined by the nominal stabilized voltage VZ of the voltage stabilizing diode 152 of the voltage stabilizing tube, the resistor 151 and the resistor 111

2) The on-resistance is mainly determined by the on-resistance of the PMOS transistor 121.

3) The response time is mainly determined by the on time of the PNP transistor 1131 and the off time of the PMOS transistor 121.

4) The DC withstand voltage is mainly determined by the withstand voltages of the source and drain of the PMOS transistor 121.

The overvoltage protection circuit shown in fig. 7 is applied to a mobile phone, and a test is performed in a mobile phone charging environment. Table 1 shows the test effect of the overvoltage protection circuit, when the PMOS transistor 121 is turned on, the current is 1A, and the PMOS transistor 121 is turned off at 8V for 5s until 30V. The current of 0 proves to be capable of bearing high voltage of 30V. The voltage is adjusted back to 5.3V, 1S is waited, the system starts charging, and the system is turned off continuously after 8V. The discrete OVP circuit thus achieves the DC overvoltage protection function and shuts off the circuit from charging when high voltage comes in.

TABLE 1

Response time of the overvoltage protection circuit shown in fig. 7 as shown in fig. 10, the response time was tested by 8/20US &1/50US surge generator (IEC610004-5), Channel (CH)1 input voltage, CH2 output voltage. It can be seen that the overvoltage protection circuit is started and shut down when a surge comes, and the high voltage lasts for 200 ns and 300 ns. From this waveform it can be seen that the overvoltage response time of the overvoltage protection circuit is in the order of ns. In fig. 10, the broken-line grid time unit is 100 ns.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. An overvoltage protection circuit, wherein the circuit comprises:

2. The circuit of claim 1, further comprising: a power input terminal for connecting with an input power source, a power output terminal for outputting a voltage, and a voltage stabilizing assembly, wherein,

the voltage stabilizing component is used for generating the reference voltage;

3. The circuit of claim 2, wherein the voltage regulation component comprises: a first resistor and a voltage stabilizing element, wherein,

4. The circuit of claim 3, wherein the voltage regulation component comprises: and a voltage regulator diode.

5. The circuit of claim 2, wherein the over-voltage protection controller comprises:

a second resistor, a third resistor, and a first switching element, wherein,

6. The circuit of claim 5, wherein the first switching element comprises: a PNP triode;

wherein,

the emitter of the PNP triode is the input end of the first switching element;

7. The circuit of claim 2, wherein the switching assembly comprises: a second switching element, wherein,

8. The circuit of claim 7, wherein the second switching element comprises: a P-channel field effect transistor;

9. The circuit of claim 8, further comprising: a fourth resistance, which is a resistance of the fourth resistor,

10. An electronic device, wherein the electronic device comprises: a load circuit and the overvoltage protection circuit of any one of claims 1 to 6; the load circuit is connected with the overvoltage protection circuit and receives the voltage output by the overvoltage protection circuit.

11. The electronic device of claim 10, wherein the electronic device comprises: a transient voltage suppressor; wherein,