CN219892937U

CN219892937U - Overvoltage and overcurrent protection circuit and device

Info

Publication number: CN219892937U
Application number: CN202320856762.6U
Authority: CN
Inventors: 吴海龙; 杨坤; 吴兴林; 朱思宏; 宋合; 刘鹏; 李海军
Original assignee: Shanghai Shuangwei Navigation Technology Co ltd
Current assignee: Shanghai Shuangwei Navigation Technology Co ltd
Priority date: 2023-04-17
Filing date: 2023-04-17
Publication date: 2023-10-24
Anticipated expiration: 2033-04-17

Abstract

The embodiment of the utility model provides an overvoltage and overcurrent protection circuit and a device, and relates to the technical field of circuits, wherein the protection circuit comprises a first protection component, a switch component, a voltage dropping component and a main controller; the step-down component is used for processing the power supply voltage provided by the external power supply into a target voltage and sending the target voltage to the main controller; the main controller is used for controlling the switch assembly to be in a target state according to the target voltage; the first protection component is used for acquiring a first voltage value and a first current value in a target state, and when the first voltage value and the first current value are not matched with a standard voltage value or a standard current value corresponding to the target state, the first protection component is disconnected so as to realize overvoltage and overcurrent protection of a load. According to the scheme provided by the embodiment, the problems of load damage risk and resource waste existing in the existing scheme when the load circuit is protected by fusing the fuse are solved, and the beneficial effect of being capable of performing quick protection response is achieved.

Description

Overvoltage and overcurrent protection circuit and device

Technical Field

The embodiment of the utility model relates to the technical field of circuits, in particular to an overvoltage and overcurrent protection circuit and device.

Background

When the existing weak current circuit system is designed, a certain measure is usually needed to protect the load in the circuit so as to prevent the load from being damaged, and the protection measures comprise overvoltage protection and overcurrent protection.

A fuse mode is generally adopted when overcurrent protection is carried out; when overvoltage protection is carried out, a transient diode (Transient Voltage Suppressor, TVS for short) or a high-molecular polymer positive coefficient temperature resistor (Polyer Positive Temperature coefficient, PPTC for short) is adopted for combined use; when the voltage value or the current value in the load circuit is detected to be abnormal, the fuse is fused, so that the effect of protecting the load is achieved.

However, the fuse takes a certain time to blow, and the load may be damaged during the process of blowing the fuse; and the fuse needs to be manually replaced after being fused, so that the phenomenon of resource waste exists.

Disclosure of Invention

The embodiment of the utility model provides an overvoltage and overcurrent protection circuit and device, which are used for improving the existing scheme for overvoltage and overcurrent protection.

In a first aspect, an embodiment of the present utility model provides an overvoltage and overcurrent protection circuit, including: the switch comprises a first protection component, a switch component, a voltage reducing component and a main controller; the external power supply is respectively connected with the first input end of the first protection component and the input end of the voltage reduction component; the output end of the step-down component is connected with the input end of the main controller; the first output end of the main controller is connected with the input end of the switch component; the second output end of the main controller is connected with the second input end of the first protection component; the input end of the switch component is connected with the third input end of the first protection component; the output end of the first protection component is connected with a load, wherein:

the step-down component is used for processing the power supply voltage provided by the external power supply into a target voltage and sending the target voltage to the main controller;

the main controller is used for controlling the switch component to be in a target state according to the target voltage, and is also used for sending the target voltage to the first protection component so that the first protection component is enabled according to the target voltage;

the first protection component is used for acquiring a first voltage value and a first current value in the target state, and when the first voltage value and the first current value are not matched with a standard voltage value or a standard current value corresponding to the target state, the first protection component is disconnected so as to realize overvoltage and overcurrent protection of the load.

Optionally, the main controller is further configured to output a high level signal when the first voltage value and the first current value match the standard voltage value and the standard current value corresponding to the target state; the first protection component is also used for conducting according to the high-level signal and inputting the power supply voltage to the load so that the load operates according to the power supply voltage.

Optionally, the circuit further comprises a second protection component; the output end of the first protection component is connected with the first input end of the second protection component, the second output end of the voltage reduction component is connected with the second input end of the second protection component, the second output end of the main controller is connected with the third input end of the second protection component, and the output end of the second protection component is connected with the load, wherein:

the step-down component is further configured to send the target voltage to the second protection component, so that the second protection component is enabled according to the target voltage;

the main controller is further configured to obtain a second voltage value and a second current value generated by the second protection component in the target state every preset time period, and when the second voltage value and the second current value exceed preset voltage values or preset current values corresponding to the target state, control the first protection component to be disconnected so as to implement overvoltage and overcurrent protection on the load.

Optionally, when the second voltage value and the second current value do not exceed the preset voltage value and the preset current value corresponding to the target state, the main controller is further configured to output a high-level signal, and the first protection component is further configured to conduct according to the high-level signal and input the power supply voltage to the second protection component; the second protection component is used for conducting according to the high-level signal and inputting the power supply voltage to the load so that the load operates according to the power supply voltage.

Optionally, when the load is a preset number, the second protection component includes a current detection resistor of the preset number, an input end of each current detection resistor is connected with an output end of the first protection component, and an output end of one current detection resistor is connected with one load, where:

the main controller is also used for obtaining a voltage difference value of the current detection resistor and obtaining the second voltage value of the current detection resistor according to the voltage difference value; and the current detection resistor is also used for acquiring a second current value corresponding to each current detection resistor.

Optionally, when the load includes a first load, a second load and a third load, the second protection component includes a first current detecting resistor, a second current detecting resistor and a third current detecting resistor, input ends of the first current detecting resistor, the second current detecting resistor and the third current detecting resistor are respectively connected with output ends of the first protection component, output ends of the first current detecting resistor are connected with the first load, output ends of the second current detecting resistor are connected with the second load, and output ends of the third current detecting resistor are connected with the third load, where:

the main controller is further configured to obtain a voltage difference value of the first current detecting resistor, the second current detecting resistor or the third current detecting resistor, and obtain the second voltage values corresponding to the first current detecting resistor, the second current detecting resistor and the third current detecting resistor according to the voltage difference value; and the second current value corresponding to the first current detection resistor, the second current detection resistor and the third current detection resistor is obtained according to the resistance values corresponding to the first current detection resistor, the second current detection resistor and the third current detection resistor and the second voltage value.

Optionally, the switch assembly includes a first switch, a second switch, and a third switch, the first switch and the second switch are connected in series, the first switch and the third switch are connected in parallel, wherein:

the controller is used for sending a state instruction to the switch component;

the switch assembly is used for controlling the first switch, the second switch and/or the third switch to be conducted according to the state instruction so as to generate the target state.

Optionally, the first protection component is implemented based on a PW1555 chip, the main controller is implemented based on a HC32F005 chip, and the buck component is implemented based on a TSP62111 chip.

Optionally, the second protection component is implemented based on the INA3221 chip.

In a second aspect, an embodiment of the present utility model provides an overvoltage and overcurrent protection device, where the overvoltage and overcurrent protection device is integrated with an overvoltage and overcurrent protection circuit provided by the embodiment of the present utility model.

The embodiment of the utility model provides an overvoltage and overcurrent protection circuit and a device, wherein the overvoltage and overcurrent protection circuit comprises a first protection component, a switch component, a voltage dropping component and a main controller; the step-down component is used for processing the power supply voltage provided by the external power supply into a target voltage and sending the target voltage to the main controller; the main controller is used for controlling the switch assembly to be in a target state according to the target voltage; the first protection component is used for acquiring a first voltage value and a first current value in a target state, and when the first voltage value and the first current value are not matched with a standard voltage value or a standard current value corresponding to the target state, the first protection component is disconnected so as to realize overvoltage and overcurrent protection of a load. According to the technical scheme provided by the embodiment of the utility model, the voltage value and the current value of the first protection component are obtained, so that when the voltage value or the current value is not matched with the standard voltage value or the standard current value corresponding to the target state, the main controller can control the first protection component to be disconnected, the purpose of protecting the load circuit is achieved, the problems of load damage risk and resource waste existing in the prior scheme when the load circuit is protected by fusing the fuse are solved, and the beneficial effect of performing quick protection response is achieved.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the utility model or to delineate the scope of the utility model. Other features of embodiments of the present utility model will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present utility model and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of an overvoltage and overcurrent protection circuit according to an embodiment of the present utility model;

FIG. 2 is a schematic diagram of another embodiment of an over-voltage and over-current protection circuit according to the present utility model;

FIG. 3 is a schematic diagram of another embodiment of an over-voltage and over-current protection circuit according to the present utility model;

FIG. 4 (a) is a schematic circuit diagram of a first protection component according to an embodiment of the present utility model;

FIG. 4 (b) is a schematic circuit diagram of a host controller according to an embodiment of the present utility model;

FIG. 4 (c) is a schematic circuit diagram of a switch assembly according to an embodiment of the present utility model;

FIG. 4 (d) is a schematic circuit diagram of a buck assembly according to an embodiment of the present utility model;

FIG. 4 (e) is a schematic circuit diagram of a second protective component provided by an embodiment of the present utility model;

fig. 5 is a schematic circuit structure diagram of an overvoltage and overcurrent protection device according to an embodiment of the present utility model.

Detailed Description

In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

Fig. 1 is a schematic structural diagram of an overvoltage and overcurrent protection circuit according to an embodiment of the present utility model, where the embodiment is applicable to the situation of performing overvoltage and overcurrent protection on a load in a circuit. Specifically, referring to fig. 1, an overvoltage and overcurrent protection circuit 100 according to an embodiment of the present utility model includes: a first protection assembly 10, a switch assembly 20, a buck assembly 30, and a main controller 40. The external power supply is respectively connected with the first input end of the first protection component 10 and the input end of the voltage reducing component 30; the output end of the voltage dropping assembly 30 is connected with the input end of the main controller 40; a first output of the main controller 40 is connected to an input of the switch assembly 20; a second output terminal of the main controller 40 is connected with a second input terminal of the first protection component 10; an output terminal of the switch assembly 20 is connected to a third input terminal of the first protection assembly 10; the output of the first protection component 10 is connected to a load.

The step-down module 30 is configured to process a power voltage provided by an external power source into a target voltage, and send the target voltage to the main controller 40.

Since the power provided by the external power source is generally high, for example, may be between 5V and 12V, in order to avoid damage to the main controller 40, the voltage reducing component 30 reduces the power voltage provided by the external power source to a target voltage that can be borne by the main controller 40, for example, the target voltage is 3.3V. The value of the specific target voltage is not limited herein, and is based on the voltage range adapted by the main controller 40.

The main controller 40 is configured to control the switching assembly 20 to be in a target state according to a target voltage, and is further configured to send the target voltage to the first protection assembly 10, so that the first protection assembly 10 is enabled according to the target voltage.

The first protection component 10 is configured to obtain a first voltage value and a first current value in a target state, and when the first voltage value and the first current value are not matched with a standard voltage value or a standard current value corresponding to the target state, the first protection component 10 is disconnected to implement overvoltage and overcurrent protection on a load. That is, the main controller 40 determines whether the overvoltage or overcurrent is generated by acquiring the first voltage value and the first current value corresponding to the first protection component 10 in the target state.

Alternatively, when the first protection component 10 is disconnected, the first protection component 10 may be disconnected in the following manner, in which first protection component 10 is implemented by a chip with an overvoltage and overcurrent protection function, for example, implemented based on a PW1555 chip; the first protection component 10 may also be controlled to be turned off by the main controller, when the first protection component 10 is controlled to be turned off by the main controller, the main controller may obtain the first voltage value and the first current value in the target state, and when the first voltage value and the first current value do not match the standard voltage value or the standard current value corresponding to the target state, the first protection component is controlled to be turned off, and the specific way of turning off the first component is not limited herein.

The switching assembly 20 may be composed of an electronic device having a switching function, and may be illustratively composed of a Metal-Oxide-semiconductor field effect transistor (MOSFET) and a transistor. The semiconductor field effect transistor can be divided into an NMOSFET and a PMOSFET according to different polarities of channels (working carriers); the transistor may include an NPN type transistor (NPN type transistor) and a PNP type transistor (PNP type transistor), and the types of semiconductor field effect transistors and transistors used in the present embodiment are not limited herein.

In one embodiment, the switch assembly 20 comprises a first switch, a second switch, and a third switch, the first switch and the second switch being in series, the first switch and the third switch being in parallel, wherein: the controller is used for sending a status instruction to the switch assembly 20; the switch assembly 20 is configured to control the first switch, the second switch, and/or the third switch to be turned on according to the status command to generate the target status.

The status instructions are used to instruct the switch assembly 20 to generate a target state, and the current target state may include a high level state, a low level state, and a floating state, so that the main controller 40 can acquire the first voltage value and the first current value of the first protection assembly 10 in the target state.

The status command may be randomly generated by the main controller 40, or a timer may be set in the main controller 40, so that the main controller 40 sends a status command to the switch assembly 20 at intervals, so that the switch assembly 20 can control the first switch, the second switch, and/or the third switch to be turned on according to the corresponding status command, so as to generate a corresponding target status. When the target states are different, the first voltage value and the first current value in the target states are also different, and the corresponding standard voltage value and standard current value in the corresponding target states are also different.

The standard voltage value and the standard current value are not limited to specific values, and may be interval values represented by range values or the like.

An implementation manner, and in particular, the overvoltage and overcurrent protection scheme provided in this embodiment may be as follows: when the main controller 40 sends a HIGH-level state command, the switch assembly 20 generates a HIGH-level signal through the HIGH-level state command, so that the power-on signal pin of the first protection assembly 10 is in a HIGH state, that is, the voltage of the power-on signal pin is the same as the voltage of the input voltage pin, and in this state, the output terminal voltage is 5V, the overvoltage threshold is 6V, that is, the standard voltage value corresponding to the HIGH state is [5, 6); when the main controller 40 sends a LOW-level state command, the switch assembly 20 generates a LOW-level signal through the LOW-level state command, so that the power-on signal pin of the first protection assembly 10 is in a LOW state, and the voltage of the power-on signal pin is connected with the Ground (GND), and in this state, for example, the voltage at the output end is 3.6V when the power-on signal pin is in the LOW state, the overvoltage threshold is 4V, that is, the standard voltage value corresponding to the LOW state is [3.6,4); when the main controller 40 sends a suspension state command (i.e. the power on signal pins of the first protection component 10 are not connected), the switch component 20 generates a suspension signal according to the suspension state command, so that the power on signal pins of the first protection component 10 are in a suspension state, and in this state, for example, in an OPEN mode, the voltage of the output terminal VOUT is 12V, the overvoltage threshold is 14V, i.e. the standard voltage value corresponding to the suspension state is [12, 14 ]. The corresponding standard voltage values for each target state are not limited herein. When the main controller 40 controls the first protection component to be in the high state, if the first voltage value of the first protection component 10 is 6.2V and exceeds the standard value [5,6 ], the first protection component 10 is disconnected when the first voltage value is determined to be unmatched with the standard voltage value corresponding to the target state, so that overvoltage and overcurrent protection on the load is realized.

According to the scheme provided by the embodiment, the working principle of overcurrent protection can be that the current standard value can be determined by acquiring the resistance value of the adjustable resistor in the first protection component 10. Specifically, the method can be determined by the following formula:

in the above, I _m The standard current value is represented, and R represents the resistance value of the adjustable resistor. For example, when the resistance of the adjustable resistor is 2.7K, the standard current value can be calculated to be about 4.07A, and the current standard current value is the maximum current threshold allowed to pass. When the current value measured through the first protection assembly 10 exceeds 4.07A, the first protection assembly 10 is disconnected to achieve overvoltage and overcurrent protection for the load.

It should be noted that, the standard current value may be freely set according to the value of the overcurrent resistance value, the maximum supporting current is 4.8A, and the selection of the specific standard current value is not limited herein.

According to the scheme provided by the embodiment, the first voltage value and the first current value of the first protection component 10 in the target state are obtained, the first voltage value and the first current value are compared with the standard voltage value or the standard current value corresponding to the target state, and when the first voltage value and the first current value are not matched with the standard voltage value or the standard current value corresponding to the target state, the first protection component 10 is controlled to be disconnected, so that quick protection response can be performed in overvoltage or overcurrent, and compared with the traditional fuse fusing mode, the efficiency is higher.

The first protection component 10 may compare the first voltage value and the first current value with the standard voltage value or the standard current value corresponding to the target state in the following manner: an analog comparator is integrated in the first protection component 10, and the analog comparator is connected with a digital-to-analog conversion module, and the digital-to-analog conversion module converts the digital signals of the first voltage value and the first current value obtained from the first protection component 10 into analog signals, and compares the analog signals with the analog comparator to obtain a comparison result and the like.

Further, in the overvoltage and overcurrent protection scheme provided in the embodiment, when the first voltage value and the first current value are matched with the standard voltage value and the standard current value corresponding to the target state, the main controller 40 is configured to output a high-level signal; the first protection component 10 is used for conducting according to a high level signal and inputting a power supply voltage to a load so that the load operates according to the power supply voltage. That is, the main controller 40 controls the output of the high level to the first protection component 10 such that the power supply voltage received by the first protection component 10 is input to the load.

The embodiment of the utility model provides an overvoltage and overcurrent protection circuit, which comprises a first protection component, a switch component, a voltage dropping component and a main controller, wherein the first protection component is connected with the switch component; the step-down component is used for processing the power supply voltage provided by the external power supply into a target voltage and sending the target voltage to the main controller; the main controller is used for controlling the switch assembly to be in a target state according to the target voltage; the first protection component is used for acquiring a first voltage value and a first current value in a target state, and when the first voltage value and the first current value are not matched with a standard voltage value or a standard current value corresponding to the target state, the first protection component is disconnected so as to realize overvoltage and overcurrent protection of a load. According to the technical scheme provided by the embodiment of the utility model, the voltage value and the current value of the first protection component are obtained, so that when the voltage value or the current value is not matched with the standard voltage value or the standard current value corresponding to the target state, the main controller can control the first protection component to be disconnected, the purpose of protecting the load circuit is achieved, the problems of load damage risk and resource waste existing in the prior scheme when the load circuit is protected by fusing the fuse are solved, and the beneficial effect of performing quick protection response is achieved.

Fig. 2 is a schematic structural diagram of another overvoltage and overcurrent protection circuit according to an embodiment of the present utility model, where the relationship between the present embodiment and the above embodiment further refines the corresponding features of the above embodiment. The overvoltage and overcurrent protection circuit scheme provided by the embodiment designs the second protection component on the basis of the overvoltage and overcurrent protection performed by the first protection component in the embodiment so as to realize double overvoltage and overcurrent protection, and the arrangement has the advantages that the second protection component is used as the supplement of the first protection component, so that overvoltage and overcurrent thresholds can be flexibly configured, the circuit connection mode of the first protection component is not required to be modified, and timely protection response to circuit abnormality can be realized.

As shown in fig. 2, on the basis of the above embodiment, the overvoltage and overcurrent protection circuit provided in this embodiment further includes: a second protective component 50. In fig. 2, the output terminal of the first protection component 10 is connected to the first input terminal of the second protection component 50, the second output terminal of the buck component 30 is connected to the second input terminal of the second protection component 50, the third output terminal of the main controller 40 is connected to the third input terminal of the second protection component 50, and the output terminal of the second protection component 50 is connected to a load, wherein:

the step-down component 30 is further configured to send the target voltage to the second protection component 50, such that the second protection component 50 is enabled according to the target voltage.

The main controller 40 is further configured to obtain a second voltage value and a second current value generated by the second protection component 50 in the target state every preset time period, and control the first protection component 10 to be disconnected when the second voltage value and the second current value exceed the preset voltage value or the preset current value corresponding to the target state, so as to implement overvoltage and overcurrent protection on the load.

Taking the power voltage input of 5.2V as an example, when the step-down component 30 detects the power voltage input from the external power source, the step-down component 30 may step down the power voltage so as to generate a target of 3.3V, thereby transmitting the target voltage to the main controller 40 and the second protection component 50 so that the second protection component 50 and the main controller 40 operate normally according to the target voltage of 3.3V.

Further, after the main controller 40 is normally started, the target state of the second protection component 50 is obtained, the second voltage value and the second current value detected in the target state are read by the main controller 40 every preset time, and when the second voltage value and the second current value exceed the preset voltage value or the preset current value corresponding to the target state, the first protection component 10 is controlled to disconnect the voltage output through the input/output pin (GPIO), so as to protect the safety of the load circuit.

When the main controller 40 obtains the second voltage value and the second current value generated by the second protection component 50 in the target state every a preset period, a clock circuit may be integrated in the main controller 40 to perform timing obtaining by the clock circuit. The predetermined period may be 5ms or 10ms, and the time interval of the specific predetermined period is not limited herein.

The overvoltage protection circuit provided in this embodiment includes a first protection component 10, a second protection component 50, a switch component 20, a step-down component 30 and a main controller 40, and realizes primary protection of a load circuit through the first protection component 10, and realizes secondary protection of the load circuit through the second protection component 50.

Specifically, the process of performing the double overvoltage and overcurrent protection may be described by taking a power supply voltage input of 5.2V as an example, when the power supply inputs 5.2V, an external power supply firstly inputs the power supply voltage to the first protection component 10 and the step-down component 30, the step-down component 30 works to generate 3.3V, and the second protection component 50 and the main controller 40 are enabled to work normally according to the 3.3V voltage, and the main controller 40 can collect the second voltage and the second current value of the second protection component 50 through an integrated circuit bus (Inter-Integrated Circuit, IIC for short); then, the main controller 40 configures an operation mode of the first protection component 10, that is, configures an input state command of a power on signal (VOVP) pin, for example, configures it to a HIGH state, and at this time, the standard voltage value of the first protection component 10 is 6V, and the standard current value is 4A (the current standard value indicates the maximum value allowed to pass) in the protection mode. Then, the main controller 40 controls the switch assembly 20 to generate a high level signal mode, so that the input end of the first protection assembly 10 inputs a high level signal, at this time, the function of the first protection assembly 10 is already started, and if the current first voltage value or the current first value exceeds the standard voltage value or the standard current value, that is, an overvoltage or overcurrent condition exists at this time, the main controller 40 controls the first protection assembly 10 to be disconnected, so that a load circuit cannot be protected in a mode of transmitting voltage to a rear-stage circuit; if the first voltage value and the first current value match the standard voltage value and the standard current value corresponding to the high level state, the main controller 40 outputs a high level signal so that the power voltage received by the first protection component 10 is input to the second protection component 50; at this time, the second protection component 50 can also collect the power access processed by the first protection component 10, which means that the second protection component 50 can detect the power working condition of the whole load circuit, the main controller 40 reads the second voltage value and the second current value of the second protection component 50 through the IIC bus, compares the second voltage value and the second current value with the preset voltage value or the preset current value in the preset high level state, and if the preset voltage value or the preset current value corresponding to the high level state is exceeded, that is, the overvoltage or overcurrent exists, the main controller 40 controls the first protection component 10 to be disconnected, so as to realize the function of turning off the power output, thereby protecting the safety of the load circuit.

Wherein the preset voltage value or the preset current value is determined according to the current target state, and the preset voltage value of the second protection component 50 in the high level state may be set to be 5.4V; setting the preset voltage value of the second protection component 50 in the low level state to be 3.8V; setting the preset voltage value of the second protection component 50 in a suspended state to be 13V; the preset current value of the second protection component 50 is set to 3.1A, and the specific preset voltage value and the preset current value are not limited herein, and the actual requirement is determined.

As can be seen from the above embodiments, the first protection component 10 provides a protection threshold, so that the first protection component can be turned on when the first voltage value and the first current value do not exceed the corresponding standard values (maximum values), and the overvoltage and overcurrent protection implemented by the second protection component 50 is first-stage finer, that is, the protection is performed before the threshold is not reached, so that the circuit components are prevented from being damaged, and the beneficial effects of saving resources and prolonging the protection life of the components can be achieved.

Further, when the second voltage value and the second current value do not exceed the preset voltage value and the preset current value corresponding to the target state, the main controller 40 is further configured to output a high-level signal, and the first protection component 10 is further configured to conduct according to the high-level signal and input the power voltage to the second protection component 50; the second protection component 50 is used for conducting according to the high level signal and inputting the power voltage to the load so that the load operates according to the power voltage. That is, the main controller 40 controls the output of the high level to the first protection component 10 such that the power voltage received by the first protection component 10 is input to the second protection component, and further controls the second protection component 50 to be turned on according to the high level signal to input the power voltage to the load.

Alternatively, when the load is a preset number, the second protection component 50 includes a preset number of current detection resistors, that is, protection of the load circuit is achieved by detecting a corresponding current value and voltage value of each current detection resistor.

Wherein the input of each current sensing resistor is connected to the output of the first protection assembly 10, and the output of one current sensing resistor is connected to a load, wherein: the main controller 40 is further configured to obtain a voltage difference value of the current detection resistor, and obtain a second voltage value of the current detection resistor according to the voltage difference value; and the second current value corresponding to each current detection resistor is also obtained.

Specifically, referring to fig. 3, fig. 3 is a schematic structural diagram of another overvoltage and overcurrent protection circuit according to an embodiment of the present utility model. When the load includes a first load, a second load and a third load, the second protection component 50 includes a first current detecting resistor 51, a second current detecting resistor 52 and a third current detecting resistor 53, input ends of the first current detecting resistor 51, the second current detecting resistor 52 and the third current detecting resistor 53 are respectively connected with output ends of the first protection component 10, output ends of the first current detecting resistor 51 are connected with the first load, output ends of the first current detecting resistor 52 are connected with the second load, and output ends of the third current detecting resistor 53 are connected with the third load, wherein:

the main controller 40 is further configured to obtain a voltage difference value of the first current detecting resistor 51, the first current detecting resistor 52, or the third current detecting resistor 53, and obtain a second voltage value corresponding to the first current detecting resistor 51, the first current detecting resistor 52, and the third current detecting resistor 53 according to the voltage difference value; and is further configured to obtain a second current value corresponding to the first current detection resistor 51, the first current detection resistor 52, and the third current detection resistor 53 according to the resistance values and the second voltage values corresponding to the first current detection resistor 51, the first current detection resistor 52, and the third current detection resistor 53, respectively. The embodiment can support overvoltage and overcurrent protection of at most three paths of loads, and can protect each path of problems.

Referring to fig. 4 (a) -4 (e), fig. 4 (a) is a schematic circuit diagram of a first protection component according to an embodiment of the present utility model; FIG. 4 (b) is a schematic circuit diagram of a host controller according to an embodiment of the present utility model; FIG. 4 (c) is a schematic circuit diagram of a switch assembly according to an embodiment of the present utility model; FIG. 4 (d) is a schematic circuit diagram of a buck assembly according to an embodiment of the present utility model; fig. 4 (e) is a schematic circuit diagram of a second protection component according to an embodiment of the present utility model.

In the overvoltage and overcurrent protection circuit provided in this embodiment, the first protection component 10 may be implemented based on a PW1555 chip, the main controller 40 may be implemented based on a HC32F005 chip, the step-down component 30 may be implemented based on a TSP62111 chip, and the second protection component 50 may be implemented based on an INA3221 chip.

In one embodiment, in fig. 4 (c), the switch assembly 20 is composed of Q1, Q2, Q3 and R1, R15, R16, R17, and the specific operation process is as follows: in fig. 4 (a), vin_5v represents an external power input, when an external power input voltage is applied, U3 generates a voltage of 3.3V to be supplied to U2 and U4, in order to enable the main controller 40 to operate normally, the main controller 40 configures the mcu_vp to output a low level, the NPN transistor at Q3 is extremely low, the collector and emitter of the transistor are not conductive, the gate voltage of the PMOS at Q1 is HIGH, so the source and drain of Q1 are conductive, the main controller 40 configures the mcu_vn is HIGH, so the source and drain of Q2 are not conductive, the power on signal (VOVP) is HIGH, the VOVP of PW1555 is in HIGH mode, the operation mode of PW1555 is output 5V, and the overvoltage threshold is 6V. Then, the main controller 40 controls the mcu_en signal to output a high level, at this time, the PW1555 is enabled to be turned on, vcc_5v has a voltage output, and since the RADJ resistance is set to 2.7K, which indicates that the overcurrent is limited to 4A, the first protection component starts to operate, and when the input voltage exceeds 6V or the current exceeds 4A, the first protection component 10 is controlled to be powered off, so as to achieve the purpose of protecting the load circuit.

Further, U4 is an INA3221 chip, and the working principle is that after the first protection component 10 operates normally, the voltage output of the first protection component 10 is used as the voltage input of the second protection component 50 to be connected to one ends of the first current detecting resistor 51, the first current detecting resistor 52 and the third current detecting resistor 53, wherein the current detecting resistors are R11, R12 and R13, when the external loads at vcc_v1, vcc_v2 and vcc_v3 work, current is generated in the current detecting resistors at this time, the voltage at two ends of each current detecting resistor forms a differential pressure, the INA3221 collects the voltages at two ends of the current detecting resistors, the main controller 40 reads the voltage values at two ends of each current detecting resistor through the IIC bus, and then calculates the actual current value according to the voltage differential value and the resistance value of each current detecting resistor. When the collected second voltage value or second current value exceeds the corresponding preset value, the protection operation is started, that is, the main controller 40 turns off the output mode of the PW1555 by outputting the MCU_EN signal to a low level so as to protect the later stage load circuit from being damaged.

According to the overvoltage and overcurrent protection circuit provided by the embodiment of the utility model, the protection scheme of the load circuit is more perfect by arranging the double protection components, so that protection response is timely carried out when the circuit is abnormal. The scheme provided by the embodiment has the advantages of low circuit design cost, more replaceable components, lower design complexity and simple realization; compared with a protection circuit built by fuses or other discrete components, the protection circuit has faster protection response capability and avoids resource waste.

Referring to fig. 5, fig. 5 is a schematic circuit diagram of an overvoltage and overcurrent protection device according to an embodiment of the utility model. The overvoltage and overcurrent protection circuit 100 provided in any one of the above embodiments is integrated on the overvoltage and overcurrent protection device 200 provided in the embodiment of the present utility model.

The overvoltage and overcurrent protection device provided by the embodiment of the utility model adopts all the technical schemes of all the embodiments of the overvoltage and overcurrent protection circuit, so that the overvoltage and overcurrent protection device at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted.

The above embodiments do not limit the scope of the present utility model. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives can occur depending upon design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included in the scope of the present utility model.

Claims

1. An overvoltage and overcurrent protection circuit, comprising: the switch comprises a first protection component, a switch component, a voltage reducing component and a main controller; the external power supply is respectively connected with the first input end of the first protection component and the input end of the voltage reduction component; the output end of the step-down component is connected with the input end of the main controller; the first output end of the main controller is connected with the input end of the switch component; the second output end of the main controller is connected with the second input end of the first protection component; the input end of the switch component is connected with the third input end of the first protection component; the output end of the first protection component is connected with a load, wherein:

2. The circuit of claim 1, wherein the main controller is further configured to output a high level signal when the first voltage value and the first current value match the standard voltage value and the standard current value corresponding to the target state; the first protection component is also used for conducting according to the high-level signal and inputting the power supply voltage to the load so that the load operates according to the power supply voltage.

3. The circuit of claim 1, further comprising a second protection component; the output end of the first protection component is connected with the first input end of the second protection component, the second output end of the voltage reduction component is connected with the second input end of the second protection component, the third output end of the main controller is connected with the third input end of the second protection component, and the output end of the second protection component is connected with the load, wherein:

4. The circuit of claim 3, wherein the main controller is further configured to output a high level signal when the second voltage value and the second current value do not exceed the preset voltage value and the preset current value corresponding to the target state, the first protection component is further configured to conduct according to the high level signal, and input the power supply voltage to the second protection component; the second protection component is used for conducting according to the high-level signal and inputting the power supply voltage to the load so that the load operates according to the power supply voltage.

5. A circuit according to claim 3, wherein when the load is a predetermined number, the second protection component comprises a predetermined number of resistors, each of the resistors having an input connected to the output of the first protection component, one of the resistors having an output connected to one of the loads, wherein:

6. The circuit of claim 5, wherein when the load comprises a first load, a second load, and a third load, the second protection component comprises a first current sensing resistor, a second current sensing resistor, and a third current sensing resistor, the inputs of the first current sensing resistor, the second current sensing resistor, and the third current sensing resistor are respectively connected to the output of the first protection component, the output of the first current sensing resistor is connected to the first load, the output of the second current sensing resistor is connected to the second load, and the output of the third current sensing resistor is connected to the third load, wherein:

7. The circuit of claim 1, wherein the switch assembly comprises a first switch, a second switch, and a third switch, the first switch and the second switch being in series, the first switch and the third switch being in parallel, wherein:

the controller is used for sending a state instruction to the switch component;

8. The circuit of claim 1, wherein the first protection component is implemented based on a PW1555 chip, the main controller is implemented based on a HC32F005 chip, and the buck component is implemented based on a TSP62111 chip.

9. The circuit of claim 3, wherein the second protection component is implemented based on an INA3221 chip.

10. An overvoltage and overcurrent protection device, characterized by comprising an overvoltage and overcurrent protection circuit according to any one of claims 1-9.