Protection device, charging device and electric driving equipment

Abstract

The utility model discloses a protection device, a charging device and electric driving equipment. The protection device comprises a current detection circuit and a current protection circuit. A detection resistor in the current detection circuit is connected in series in the circuit to be detected, and the current detection circuit is configured to generate a current detection signal based on the detection resistor; in the current protection circuit, the input end of a comparison unit is connected with the output end of a current detection circuit, the output end of the comparison unit is connected with the input end of a switch unit, and the output end of the switch unit is connected with the input end of a protection unit; the current protection circuit is configured to receive a current detection signal through the input end of the comparison unit, and generate an initial signal through the switch unit when the voltage value of the current detection signal is higher than an upper limit reference voltage or lower than a lower limit reference voltage; and when the protection unit detects that the level state of the initial signal is overturned, a current protection signal is output through the protection unit. Therefore, the safety and reliability of equipment can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic power technical field especially relates to a protection device, charging device and electric drive equipment. BACKGROUND

[0002] In new energy vehicles, the on-board charger is a crucial component, which plays a core role in providing charging services for new energy vehicles. It can convert alternating current into direct current and charge new energy vehicles.

[0003] In related technologies, in order to ensure the safety of the on-board charger, an overcurrent protection circuit is generally required. However, due to some defects in the overcurrent protection circuit in related technologies, such as large action delay time and low reliability, the overcurrent protection function has a risk of failure. SUMMARY

[0004] The utility model provides a protection device, charging device and electric drive equipment, can appear overcurrent or undercurrent fault in the circuit under test quickly trigger protection function, improve the safety and reliability of equipment.

[0005] The technical solution of the utility model is as follows:

[0006] In a first aspect, the utility model embodiment provides a protection device, which includes a current detection circuit and a current protection circuit, wherein:

[0007] The current detection circuit includes a detection resistor, and the detection resistor is connected in series in the circuit under test. The current detection circuit is configured to generate a current detection signal based on the detection resistor.

[0008] The current protection circuit includes a comparison unit, a switching unit and a protection unit. The input end of the comparison unit is connected with the output end of the current detection circuit. The output end of the comparison unit is connected with the input end of the switching unit. The output end of the switching unit is connected with the input end of the protection unit.

[0009] The current protection circuit is configured to receive the current detection signal through the input end of the comparison unit. When the voltage value of the current detection signal is higher than the upper limit reference voltage or the voltage value of the current detection signal is lower than the lower limit reference voltage, the switching unit generates an initial signal. When the protection unit detects that the level state of the initial signal is reversed, the protection unit outputs a current protection signal.

[0010] By the above technical means, the detection resistor in the current detection circuit is connected in series in the to-be-detected circuit, the to-be-detected circuit is detected by the detection resistor to generate a current detection signal, the voltage value of the current detection signal is compared with the upper limit reference voltage and the lower limit reference voltage by the comparison unit, and when the voltage value of the current detection signal is higher than the upper limit reference voltage or lower than the lower limit reference voltage, the initial signal is generated by the switching unit; and when the level state of the initial signal is reversed, the current protection signal is output by the protection unit. In this way, the detection resistor can quickly detect the current of the to-be-detected circuit, shorten the current detection time of the protection device, and quickly trigger the current protection function when the to-be-detected circuit has a current fault; and the comparison unit judges the overcurrent or undercurrent of the current detection signal, which not only can realize the current protection function when the to-be-detected circuit is in an overcurrent or undercurrent state, but also can widen the application scenario of the protection device and improve the safety and reliability of the equipment. In addition, considering that the overcurrent or undercurrent occurs for a short time in some scenarios, the protection unit outputs the current protection signal at the moment when the level state of the initial signal is reversed, so that the fault phenomenon of overcurrent or undercurrent can be accurately captured, and the overcurrent protection function can be quickly triggered when the fault phenomenon occurs, further improving the safety and reliability of the equipment.

[0011] In some embodiments, the current detection circuit further comprises a filtering unit and an amplifying unit; wherein: the input end of the filtering unit is connected across the detection resistor, and is configured to filter the first current signal generated by the detection resistor to generate a second current signal; and the amplifying unit is connected with the output end of the filtering unit, and is configured to amplify the second current signal to generate the current detection signal.

[0012] By the above technical means, considering that the current signal generated by the detection resistor is relatively weak, the first current signal generated by the detection resistor is filtered by the filtering unit to obtain an accurate second current signal, and the second current signal is amplified by the amplifying unit to generate the current detection signal, which is convenient for subsequent circuit processing and analysis, and further improves the accuracy of current detection of the to-be-detected circuit.

[0013] In some embodiments, the filtering unit comprises a differential mode filtering component, a common mode filtering component, a first filtering component, and a current limiting component, wherein: the differential mode filtering component comprises a first capacitor, the common mode filtering component comprises a second capacitor and a third capacitor, the first filtering component comprises a fourth capacitor, a first inductor, and a second inductor, and the current limiting component comprises a first resistor and a second resistor; a first end of the first capacitor is connected to a first end of a detection resistor, a first end of the second capacitor, and a first end of the first inductor, respectively; a second end of the first capacitor is connected to a second end of the detection resistor, a second end of the third capacitor, and a first end of the second inductor; a first end of the first inductor is also connected to the first end of the second capacitor, and a second end of the first inductor is connected to a first end of the first resistor; a first end of the third capacitor is connected to the second end of the second capacitor and a first output end of the circuit to be detected, respectively, a second end of the third capacitor is also connected to the first end of the second inductor, and a second end of the second inductor is connected to a first end of the second resistor; a first end of the fourth capacitor is connected to a second end of the first resistor, and a second end of the fourth capacitor is connected to a second end of the second resistor.

[0014] Through the above technical means, the differential mode interference signal is filtered out by the differential mode filtering component, the common mode interference in the signal transmission process is eliminated by the common mode filtering component, and filtering is performed by the first filtering component, which can effectively suppress high-frequency noise, electromagnetic interference, etc. in the circuit, and can obtain an accurate second current signal, thereby improving the accuracy of current detection. Moreover, the current limiting component can achieve the purpose of current limiting and also improve the safety of the circuit.

[0015] In some embodiments, the amplifying unit comprises an operational amplification component; wherein: an inverting input end of the operational amplification component is connected to a second end of the first resistor and a first end of the fourth capacitor, respectively, a non-inverting input end of the operational amplification component is connected to a second end of the second resistor and a second end of the fourth capacitor, respectively, a reference end of the operational amplification component is connected to a first power supply, a power supply end of the operational amplification component is connected to a second power supply, a ground end of the operational amplification component is connected to ground, and an output end of the operational amplification component is used to output a current detection signal.

[0016] Through the above technical means, considering that the current signal generated by the detection resistor is relatively weak, the operational amplification component can be used to amplify the current signal generated by the detection resistor to generate a current detection signal, which is convenient for subsequent circuit processing and analysis, thereby improving the accuracy of current detection of the circuit to be detected.

[0017] In some embodiments, the comparison unit comprises a first comparison component and a second comparison component; wherein: the non-inverting input terminal of the first comparison component is connected with the first reference circuit, the inverting input terminal of the second comparison component is connected with the second reference circuit, the inverting input terminal of the first comparison component and the non-inverting input terminal of the second comparison component are respectively connected with the output terminal of the current detection circuit, and the output terminal of the first comparison component and the output terminal of the second comparison component are respectively connected with the input terminal of the switch unit; the power supply terminal of the first comparison component is connected with the third power supply, the ground terminal of the first comparison component is connected with the ground, the power supply terminal of the second comparison component is connected with the fourth power supply, and the ground terminal of the second comparison component is connected with the ground.

[0018] Through the above technical means, the overcurrent or undercurrent of the current detection signal is judged by the first comparison component and the second comparison component, which not only can realize the current protection function when the to-be-tested circuit is in the overcurrent or undercurrent state, but also can widen the application scene of the protection device and improve the safety and reliability of the equipment.

[0019] In some embodiments, the switch unit comprises a third resistor, a fourth resistor, a fifth resistor and a transistor; wherein: the first terminal of the third resistor is connected with the fifth power supply, the second terminal of the third resistor is respectively connected with the output terminal of the first comparison component, the output terminal of the second comparison component and the first terminal of the transistor; the first terminal of the fourth resistor is connected with the sixth power supply, and the second terminal of the fourth resistor is connected with the second terminal of the transistor; the third terminal of the transistor is respectively connected with the first terminal of the fifth resistor and the input terminal of the protection unit, the second terminal of the fifth resistor is connected with the ground, and the third terminal of the transistor is used for outputting an initial signal.

[0020] Through the above technical means, when the first comparison component and the second comparison component judge that the to-be-tested circuit is in the overcurrent or undercurrent state according to the current detection signal, the transistor of the switch unit and each resistor can output the initial signal, and then the protection unit outputs the current protection signal, so that the current protection function of the subsequent circuit is started, and the safety and reliability of the equipment are further improved.

[0021] In some embodiments, the protection unit comprises an edge trigger component and a sixth resistor; wherein: the first terminal of the sixth resistor is respectively connected with the third terminal of the transistor and the first terminal of the fifth resistor, and the second terminal of the sixth resistor is connected with the clock signal terminal of the edge trigger component; the power supply terminal of the edge trigger component and the output terminal of the edge trigger component are respectively connected with the seventh power supply, the ground terminal of the edge trigger component is connected with the ground, and the output terminal of the edge trigger component is further used for outputting the current protection signal when the level state of the clock signal terminal is detected to be reversed.

[0022] By the technical means, the sixth resistor is used for current limiting, so that the edge trigger component is prevented from being damaged due to an excessively large input voltage of the clock signal end; in addition, considering that the overcurrent or undercurrent occurs for a short time in some scenarios, the edge trigger component outputs the current protection signal at the moment when the level state of the initial signal is detected to be reversed, so that the overcurrent or undercurrent fault phenomenon can be accurately captured, and the overcurrent protection function is triggered quickly when the fault phenomenon occurs, and the safety and reliability of the device are further improved.

[0023] In some embodiments, the protection unit further includes an anti-reverse component, wherein: a first end of the anti-reverse component is connected with the output end of the edge trigger component, and a second end of the anti-reverse component is connected with an output port for outputting the current protection signal.

[0024] By the technical means, the anti-reverse component is used to prevent the current from flowing in the reverse direction, so that the elements in the circuit are protected from damage, and the safety of the circuit is improved.

[0025] In some embodiments, the protection unit further includes a voltage dividing component, and the voltage dividing component includes a seventh resistor and an eighth resistor, wherein: a first end of the seventh resistor is connected with the second end of the anti-reverse component; a second end of the eighth resistor is connected with the ground, and a second end of the seventh resistor and a first end of the eighth resistor are connected with the output port, respectively.

[0026] By the technical means, the voltage dividing component can protect the subsequent circuit, for example, when the output voltage of the output end of the edge trigger component is excessively large, the voltage dividing component can share a part of the voltage, so as to prevent the subsequent circuit from being damaged due to overvoltage.

[0027] In some embodiments, the first reference circuit includes a ninth resistor, a tenth resistor and a first reference power supply, and the second reference circuit includes an eleventh resistor, a twelfth resistor and a second reference power supply, wherein: in the first reference circuit, a first end of the ninth resistor is connected with the first reference power supply, a second end of the ninth resistor and a first end of the tenth resistor are connected with the same-phase input end of the first comparison component, respectively, and a second end of the tenth resistor is connected with the ground, and the first reference circuit is used for providing an upper limit reference voltage; in the second reference circuit, a first end of the eleventh resistor is connected with the second reference power supply, a second end of the eleventh resistor and a first end of the twelfth resistor are connected with the inverse-phase input end of the second comparison component, respectively, and a second end of the twelfth resistor is connected with the ground, and the second reference circuit is used for providing a lower limit reference voltage.

[0028] By the above technical means, the ninth resistor and the tenth resistor are used for voltage division of the first reference power supply, avoiding damage of the first comparison component due to excessive input voltage of the non-inverting input terminal; the eleventh resistor and the twelfth resistor are used for voltage division of the second reference power supply, avoiding damage of the second comparison component due to excessive input voltage of the inverting input terminal; in addition, the first reference circuit provides an upper limit reference voltage, and the second reference circuit provides an upper limit reference voltage, by changing the first reference power supply and the second reference power supply, the upper limit reference voltage and the lower limit reference voltage can be changed, the current detection range of the protection device can be expanded, and the application scene of the protection device is widened.

[0029] In a second aspect, the utility model provides a charging device, the charging device includes the protection device that any one of the first aspect is measured circuit.

[0030] In a third aspect, the utility model provides an electric drive device, the electric drive device includes the charging device of the second aspect.

[0031] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, but not limiting the technical scheme of the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The utility model provides a kind of component structure schematic diagram of protection device for utility model embodiment;

[0033] Figure 2 The utility model provides a kind of component structure schematic diagram of current detection circuit for utility model embodiment Figure 1 ;

[0034] Figure 3 The utility model provides a kind of component structure schematic diagram of current detection circuit for utility model embodiment Figure 2 ;

[0035] Figure 4 The utility model provides a kind of component structure schematic diagram of current detection circuit for utility model embodiment Figure 3 ;

[0036] Figure 1 The utility model provides a kind of component structure schematic diagram of current protection unit for utility model embodiment Figure 1 ;

[0037] Figure 2 The utility model provides a kind of component structure schematic diagram of current protection unit for utility model embodiment Figure 3 ;

[0038] Figure 3 The utility model provides a kind of component structure schematic diagram of current protection unit for utility model embodimentFigure 8 ;

[0039] Figure 9 A processing flow schematic diagram of a protection device is provided for the embodiment of the utility model;

[0040] Figure 10 A component structure schematic diagram of a charging device is provided for the embodiment of the utility model;

[0041] Figure 1 A component structure schematic diagram of an electric drive device is provided for the embodiment of the utility model. DETAILED DESCRIPTION

[0042] In order to be able to more detailedly understand the characteristics and technical contents of the embodiments of the utility model, the implementation of the embodiments of the utility model is described in detail below in combination with the drawings, and the drawings are only used for reference and are not used to limit the embodiments of the utility model.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs. The terms used herein are only for the purpose of describing the embodiments of the utility model and are not intended to limit the utility model.

[0044] In the following description, "some embodiments" are described, which describe a subset of all possible embodiments, but it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0045] It should also be noted that the terms "first, second, third" involved in the embodiments of the utility model are only used to distinguish similar objects and do not represent a specific order of the objects. It can be understood that "first, second, third" can be interchanged in a specific order or sequence as allowed, so that the embodiments of the utility model described herein can be implemented in an order other than that illustrated or described herein.

[0046] In addition, the reference to "embodiments" in this document means that the specific features, structures or characteristics described in conjunction with the embodiments can be included in at least one embodiment of the utility model. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] The related technologies of the utility model are introduced below.

[0048] New energy batteries are increasingly widely used in life and industry. For example, new energy vehicles equipped with batteries have been widely used, and batteries are also increasingly used in the field of energy storage and the like.

[0049] Currently, new energy batteries are increasingly widely used in life and industry. New energy batteries are not only applied to energy storage power supply systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also increasing.

[0050] In the embodiments of the present application, the battery can be a battery monomer, or a battery pack (Pack) composed of a plurality of battery monomers. The battery monomer refers to a basic unit capable of realizing mutual conversion between chemical energy and electrical energy, which can be used to make a battery module or a battery pack, thereby being used to supply power to an electrical device. The battery monomer can be a secondary battery, which refers to a battery monomer that can be activated by charging after discharging. The battery monomer can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, etc. The embodiments of the present application are not limited thereto.

[0051] In the embodiments of the present application, the battery can also be a single physical module including one or more battery monomers to provide higher voltage and capacity. When there are a plurality of battery monomers, the plurality of battery monomers are connected in series, parallel or mixed connection through a current combining component.

[0052] Further, with the continuous development of new energy technology, new energy vehicles have been widely used due to their economy and environmental protection. In new energy vehicles, the on-board charger is a crucial component, which plays a core role in providing charging services for new energy vehicles. It can convert alternating current into high-voltage direct current to charge new energy vehicles. Specifically, the on-board charger uses a two-stage conversion structure. The on-board charger first rectifies alternating current through an alternating current / direct current (AC / DC) converter, then inputs the rectified direct current into a direct current / direct current (DC / DC) converter to adjust the direct current voltage, and finally inputs the adjusted direct current into the battery pack of the new energy vehicle. In related technologies, in order to ensure the safety of the on-board charger, an overcurrent protection circuit is generally required to implement overcurrent protection for the on-board charger.

[0053] In a possible implementation, the on-board charger includes an AC / DC converter, a DC / DC converter, and an overcurrent protection circuit, the AC / DC converter and the DC / DC converter are both driven by a photocoupler, and the overcurrent protection circuit includes a current detection unit, an overcurrent protection unit, and a control unit; the current detection unit is a Hall sensor, the Hall sensor detects the output current of the DC / DC converter to output a current detection value, the overcurrent protection unit is configured to output an overcurrent protection signal, and the control unit is configured to, when the overcurrent protection signal is received, close a control signal output channel of a SiC switch tube, so that the AC / DC converter and the DC / DC converter stop working. Although the overcurrent protection circuit can trigger the overcurrent protection function when an overcurrent fault occurs in the on-board charger, and the safety of the on-board charger is improved, the time required for the Hall sensor to change from a magnetic field to a sensor output signal is relatively large, the action delay time of the overcurrent protection circuit is relatively large, the overcurrent protection function may fail, and the safety of the on-board charger is seriously affected. Moreover, if there is strong magnetic field interference, the Hall sensor will be affected, and the reliability of the scheme is reduced. In addition, the overcurrent protection circuit can only achieve one-way overcurrent protection for the charging loop, and the charging reliability of the on-board charger is further reduced.

[0054] It can be understood that, due to the defects of the overcurrent protection circuit in the related art, for example, the large action delay time and the low reliability, the overcurrent protection function may fail.

[0055] Therefore, the utility model discloses an overcurrent protection circuit and an overcurrent protection device, which can solve the problems of the prior art.

[0056] The utility model discloses an overcurrent protection circuit and an overcurrent protection device, which can solve the problems of the prior art.

[0057] In an embodiment of the utility model,Figure 1 A schematic diagram of a composition structure of a protection device is provided in the embodiment of the utility model. As shown in the figure, Figure 2 The protection device 10 can include a current detection circuit 101 and a current protection circuit 102; wherein:

[0058] The current detection circuit 101 includes a detection resistor Rt, and the detection resistor Rt is connected in series in the circuit to be detected. The current detection circuit 101 is configured to generate a current detection signal Ac based on the detection resistor Rt.

[0059] The current protection circuit 102 includes a comparison unit 1021, a switching unit 1022 and a protection unit 1023, and the input end of the comparison unit 1021 is connected with the output end of the current detection circuit 101. The output end of the comparison unit 1021 is connected with the input end of the switching unit 1022. The output end of the switching unit 1022 is connected with the input end of the protection unit 1023.

[0060] The current protection circuit 102 is configured to receive the current detection signal Ac through the input end of the comparison unit 1021. When the voltage value of the current detection signal Ac is higher than the upper limit reference voltage or the voltage value of the current detection signal Ac is lower than the lower limit reference voltage, the switching unit 1022 generates an initial signal. When the protection unit 1023 detects that the level state of the initial signal is reversed, the protection unit 1023 outputs a current protection signal Ap.

[0061] In the embodiment of the utility model, the circuit to be detected can be located in the vehicle charger, and the vehicle charger can include a DC / DC converter. The DC / DC converter is used to convert the high-voltage direct current of the battery pack into low-voltage direct current to meet the charging demand of the vehicle. Therefore, the circuit to be detected can also be called a charging loop, or it can also be called a DCDC charging loop.

[0062] In the embodiment of the utility model, the current detection signal can be called A-current signal, which can be abbreviated as Ac. The current protection signal can be called A-protect signal, which can also be abbreviated as Ac. Here, the current detection signal can be a voltage value, which is the voltage converted by the detection resistor from the current through Ohm's law. In addition, the current protection signal can also be a voltage value, which is not limited.

[0063] In the embodiment of the utility model, the upper limit reference voltage can be called the upper limit voltage, and the lower limit reference voltage can be called the lower limit voltage. The upper limit reference voltage is greater than the lower limit reference voltage. The values of the upper limit reference voltage and the lower limit reference voltage are determined according to the actual situation. For example, the upper limit reference voltage is 7 volts (V), and the lower limit reference voltage is 2V.

[0064] Here, if the current detection signal is greater than the upper limit reference voltage, the to-be-tested circuit has an overcurrent fault; if the current detection signal is less than the lower limit reference voltage, the to-be-tested circuit has an undercurrent fault. That is, the protection device can perform overcurrent detection and undercurrent detection on the to-be-tested circuit, thereby realizing overcurrent or undercurrent protection of the to-be-tested circuit.

[0065] In some embodiments, the detection resistor Rt can be a shunt resistor SHUNT.

[0066] In the embodiment of the utility model, when the to-be-tested circuit starts charging, the shunt resistor is used to measure the current of the to-be-tested circuit. Since the shunt resistor has an extremely low resistance value, when the current passes through the entire circuit, part of the current passes through the shunt resistor, and the other part of the current passes through other components. The current of the to-be-tested circuit is detected according to the voltage drop across the shunt resistor and using Ohm's law.

[0067] It should be noted that the use of the shunt resistor is faster and more reliable than the use of the Hall sensor to detect the current in the related art. The main reason is that the Hall sensor has a zero drift risk (the phenomenon that the output electrical signal of the sensor is not zero under the action of no magnetic field), and the Hall sensor will also generate current under the interference of external strong magnetic field, resulting in low measurement accuracy. In addition, the Hall sensor needs a connector to connect with the circuit board where the circuit is located, and needs response time when detecting current. The shunt resistor can be directly absorbed and soldered on the circuit board where the circuit is located, without the need for a connector, and has faster response speed, shorter current detection time, and higher reliability.

[0068] In the embodiment of the utility model, after the protection unit 1023 outputs the current protection signal, the current protection signal can be transmitted to the microcontroller unit (MCU), and the MCU drives the current protection function to realize protection of the to-be-tested circuit and improve the safety of the to-be-tested circuit. It should be noted that the current detection signal Ac and the current protection signal can exist in the form of voltage.

[0069] The utility model embodiment provides a kind of protection device, using detection resistance can realize the current of the circuit to be measured to carry out rapid detection, shorten the current detection time of protection device, to quickly trigger current protection function when the current fault of the circuit to be measured appears;And using comparison unit carries out overcurrent or undercurrent judgment to current detection signal, not only can realize the current protection function when the circuit to be measured is in overcurrent or undercurrent state, but also can widen the application scenario of protection device, improve the security and reliability of equipment;In addition, considering that the time of overcurrent or undercurrent occurs under part scene is shorter, protection unit is used to output current protection signal when the level state of initial signal is detected to reverse moment, to accurately capture the fault phenomenon of overcurrent or undercurrent occurrence, and quickly trigger overcurrent protection function when fault phenomenon appears, further improve the security and reliability of equipment.

[0070] In still another embodiment of the utility model, Figure 1 A composition structure of current detection circuit is provided for the utility model embodiment Figure 2 . As Figure 3 Indicated, current detection circuit 101 can also include filter unit 201 and amplification unit 202;Wherein:

[0071] The input end of filter unit 201 is connected at the two ends of detection resistance Rt, is configured to filter the first current signal generated by detection resistance Rt, generates second current signal;Amplification unit 202 is connected with the output end of filter unit 201, is configured to amplify second current signal, generates current detection signal Ac.

[0072] In some embodiments, as Figure 4 Indicated, filter unit 201 includes first capacitor C1, second capacitor C2, third capacitor C3, fourth capacitor C4, first inductor L1, second inductor L2, first resistance R1 and second resistance R2;Wherein:

[0073] The first end of first capacitor C1 is connected with the first end of detection resistance Rt, the first end of second capacitor C2, the first end of first inductor L1 respectively;The second end of first capacitor C1 is connected with the second end of detection resistance Rt, the second end of third capacitor C3 and the first end of second inductor L2;The first end of first inductor L1 is also connected with the first end of second capacitor C2, the first end of first inductor L1 is connected with the first end of first resistance R1;The first end of third capacitor C3 is connected with the second end of second capacitor C2 and the first output end of circuit to be measured respectively, the second end of third capacitor C3 is also connected with the first end of second inductor L2, the second end of second inductor L2 is connected with the first end of second resistance R2;The first end of fourth capacitor C4 is connected with the second end of first resistance R1, the second end of fourth capacitor C4 is connected with the second end of second resistance R2.

[0074] In the embodiment of the utility model, filter unit 201 includes difference mode filter component, common mode filter component, first filter component and current limiting component, wherein: first capacitor C1 constitutes difference mode filter component, second capacitor C2 and third capacitor C3 constitute common mode filter component, fourth capacitor C4, first inductor L1 and second inductor L2 constitute first filter component, first resistor R1 and second resistor R2 constitute current limiting module. It needs to be explained that first capacitor C1 is X capacitor, second capacitor C2 and third capacitor C3 are Y capacitors.

[0075] Here, the difference mode interference signal is filtered out by the difference mode filter component, and the circuit performance is improved. The common mode interference in the signal transmission process is eliminated by the common mode filter component, and the performance of the circuit is further improved. In addition, the first inductor L1 and the second inductor L2 can be magnetic beads. The first inductor L1, the second inductor L2 and the fourth capacitor C4 can effectively suppress high-frequency noise and electromagnetic interference in the circuit, and protect the stability and reliability of the circuit. In addition, the first resistor R1 and the second resistor R2 can achieve the purpose of current limiting, thereby improving the safety of the circuit.

[0076] It can be understood that the difference mode interference signal is filtered out by the difference mode filter component, the common mode interference in the signal transmission process is eliminated by the common mode filter component, and the first filter component is filtered. High-frequency noise, electromagnetic interference and other interference in the circuit can be effectively suppressed to obtain accurate second current signals, thereby improving the accuracy of current detection. Moreover, the current limiting component can achieve the purpose of current limiting, and can also improve the safety of the circuit.

[0077] In some embodiments, as shown in Figure 4 The amplification unit 201 includes an operational amplification component U1. The inverting input end (IN-) of the operational amplification component U1 is connected with the second end of the first resistor R1 and the first end of the fourth capacitor C4, respectively. The non-inverting input end (IN+) of the operational amplification component U1 is connected with the second end of the second resistor R2 and the second end of the fourth capacitor C4, respectively. The reference end (REF) of the operational amplification component U1 is connected with the first power supply V1. The power supply end (VS) of the operational amplification component U1 is connected with the second power supply V2. The ground end (GND) of the operational amplification component U1 is connected with the ground. The output end (OUT) of the operational amplification component U1 is used for outputting the current detection signal Ac.

[0078] In the embodiment of the utility model, the first power supply V1 can be equal to or different from the second power supply V2. For example, the first power supply V1 can be different from the second power supply V2. The first power supply V1 is 2.5V, and the second power supply V2 is 5V.

[0079] In the embodiment of the utility model, continue as Figure 5As shown, the amplification circuit further comprises a fifth capacitor C5, a sixth capacitor C6 and a seventh capacitor C7. The first end of the fifth capacitor C5 is connected between the reference end (REF) of the operational amplification component U1 and the first power supply V1, the second end of the fifth capacitor C5 is connected to the ground, for filtering the first power supply V1, so as to filter out the high-frequency noise and ripple in the first power supply V1, and ensure that a stable and clean direct current reference power supply is obtained; the first end of the sixth capacitor C6 is connected between the power supply end (VS) of the operational amplification component U1 and the second power supply V2, the second end of the sixth capacitor C6 is connected to the ground, for filtering the second power supply V2, so as to filter out the high-frequency noise and ripple in the second power supply V2, and ensure that a stable and clean direct current power supply is obtained; the first end of the seventh capacitor C7 is connected between the output end (OUT) of the operational amplification component U1 and the input end of the comparison unit, the second end of the seventh capacitor C7 is connected to the ground, for filtering out the high-frequency noise and stray components in the output signal, and ensuring the purity and stability of the output current detection signal Ac.

[0080] It should be noted that the operational amplification component U1 can be referred to as an operational amplifier, for example, the operational amplification component U1 can be a general-purpose operational amplifier, or the operational amplification component U1 can also be a high-precision operational amplifier, and no limitation is made on this.

[0081] It should be further noted that if the detection resistor Rt collects a weak voltage, for example, a millivolt-level voltage, if direct subsequent comparison is performed, the voltage can be disturbed during the transmission process, affecting the judgment of the current detection signal of the to-be-measured circuit, therefore, at this time, the operational amplification component U1 can be used to amplify the voltage collected by the detection resistor Rt, so as to ensure subsequent judgment, and thus improve the accuracy of the current detection of the to-be-measured circuit.

[0082] That is, considering that the current signal generated by the detection resistor is relatively weak, the operational amplification component can be used to amplify the current signal generated by the detection resistor to generate a current detection signal, which is convenient for subsequent circuit processing and analysis, and thus improves the accuracy of the current detection of the to-be-measured circuit.

[0083] The utility model embodiment provides a kind of protection device, and the first current signal generated by the detection resistor is filtered by filter unit, accurate second current signal can be obtained, and the second current signal is amplified to generate current detection signal by amplification unit, it is convenient for subsequent circuit processing and analysis, and thus improves the accuracy of the current detection of the to-be-measured circuit.

[0084] In another embodiment of the utility model, Figure 1 The utility model embodiment provides a kind of composition structure of current protection unit Figure 5 . As Figure 5As shown, the comparison unit 1021 comprises a first comparison component U2 and a second comparison component U3; wherein:

[0085] The non-inverting input end (+) of the first comparison component U2 is connected with the first reference circuit 501, the inverting input end (-) of the second comparison component is connected with the second reference circuit 502, the inverting input end (-) of the first comparison component U2 and the non-inverting input end (+) of the second comparison component U3 are respectively connected with the output end of the current detection circuit, and the output end of the first comparison component U2 and the output end of the second comparison component U3 are respectively connected with the input end of the switch unit 1022; the power supply end of the first comparison component U2 is connected with the third power supply V3, the grounding end of the first comparison component U2 is connected with the ground, the power supply end of the second comparison component U3 is connected with the fourth power supply V4, and the grounding end of the second comparison component U3 is connected with the ground.

[0086] In the embodiment of the utility model, two comparison components are used to calculate the current detection signal Ac. Taking the first comparison component U2 as an example, if the voltage of the non-inverting input end (+) of the first comparison component U2 is greater than the voltage of the inverting input end (-) of the first comparison component U2 (i.e. U1 + >U 1- ), the output end of the first comparison component U2 outputs a high level signal (i.e. U1 out =U H ); if the voltage of the non-inverting input end (+) of the first comparison component U2 is less than the voltage of the inverting input end (-) of the first comparison component U2 (i.e. U1 + <U 1- ), the output end of the first comparison component U2 outputs a low level signal (i.e. U1 out =U L ).

[0087] That is to say, after the current detection signal Ac is transmitted to the comparison unit 1021, the first comparison component U2 and the second comparison component U3 calculate the current detection signal Ac, when the current detection signal Ac exceeds the upper limit reference voltage set by the first comparison component U2, the output end of the first comparison component U2 outputs a low level signal and the output end of the second comparison component U3 outputs a high level signal, at this time, the to-be-tested circuit has an overcurrent fault; when the current detection signal Ac is lower than the lower limit reference voltage set by the second comparison component U3, the output end of the first comparison component U2 outputs a high level signal and the output end of the second comparison component U3 outputs a low level signal, at this time, the to-be-tested circuit has an undercurrent fault. When the current detection signal Ac is within the set upper limit reference voltage and lower limit reference voltage, the output ends of the first comparison component U2 and the second comparison component U3 both output high level signals, at this time, the to-be-tested circuit has no abnormality. It can be understood that when the level signals output by the output ends of the first comparison component U1 and the second comparison component U3 are inconsistent, it indicates that the to-be-tested circuit has an undercurrent or overcurrent fault.

[0088] It should be noted that the first comparison component U2 can be called the first comparator, and the second comparison component U3 can be called the second comparator. The first comparison component U2 and the second comparison component U3 can be comparators of the same type or different types; this is not limited.

[0089] In some embodiments, continue as follows Figure 5 As shown, the comparison unit 1021 may further include an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, and a twelfth capacitor C12; wherein:

[0090] The first terminal of the eighth capacitor C8 is connected to ground, and the second terminal of the eighth capacitor C8 is connected between the third power supply V3 and the power supply terminal of the first comparator U2; the first terminal of the ninth capacitor C9 is connected between the output terminal of the first comparator U2 and the input terminal of the switching unit 1022, and the second terminal of the ninth capacitor C9 is connected to ground; the first terminal of the tenth capacitor C10 is connected between the output terminal of the second comparator U3 and the input terminal of the switching unit 1022, and the second terminal of the tenth capacitor C10 is connected to ground; the first terminal of the eleventh capacitor C11 is connected between the first reference circuit 501 and the non-inverting input terminal (+) of the first comparator U2, and the second terminal of the eleventh capacitor C11 is connected to ground; the first terminal of the twelfth capacitor C12 is connected between the second reference circuit 502 and the inverting input terminal (-) of the first comparator U2, and the second terminal of the twelfth capacitor C12 is connected to ground.

[0091] In this embodiment of the invention, the eighth capacitor C8, the ninth capacitor C9, the tenth capacitor C10, the eleventh capacitor C11, and the twelfth capacitor C12 are all filter capacitors used to filter the corresponding power supplies to remove high-frequency noise and ripple, ensuring a stable and clean DC power supply. The ninth capacitor C9 and the tenth capacitor C10 are used to filter high-frequency noise and stray components in the corresponding output signal, ensuring the purity and stability of the output signal. Furthermore, the third and fourth power supplies can be equal, for example, both 5V, or they can be unequal, depending on the actual situation. Additionally, the two comparison components can be mounted on the same circuit board, and the power draw locations of the third and fourth power supplies are the same, such as... Figure 5 As shown, here we only need to place a filter capacitor at the input of the third power supply.

[0092] It can be understood that the overcurrent or undercurrent judgment of the current detection signal by the first comparison component and the second comparison component not only can realize the current protection function when the to-be-tested circuit is in the overcurrent or undercurrent state, but also can widen the application scene of the protection device and improve the safety and reliability of the equipment.

[0093] In some embodiments, continuing as Figure 6 shown, the first reference circuit 501 includes a ninth resistor R9, a tenth resistor R10 and a first reference power supply Vref1, and the second reference circuit 502 includes an eleventh resistor R11, a twelfth resistor R12 and a second reference power supply Vref2, wherein:

[0094] In the first reference circuit 501, the first end of the ninth resistor R9 is connected with the first reference power supply Vref1, the second end of the ninth resistor R9 and the first end of the tenth resistor R10 are respectively connected with the non-inverting input end (+) of the first comparison component U2, the second end of the tenth resistor R10 is connected with the ground, and the first reference circuit 501 is used for providing an upper limit reference voltage;

[0095] In the second reference circuit 502, the first end of the eleventh resistor R11 is connected with the second reference power supply Vref2, the second end of the eleventh resistor R11 and the first end of the twelfth resistor R12 are respectively connected with the inverting input end (-) of the second comparison component U3, and the second end of the twelfth resistor R12 is connected with the ground, and the second reference circuit 502 is used for providing a lower limit reference voltage.

[0096] In the embodiment of the utility model, the ninth resistor R9 and the tenth resistor R10 are used for voltage division of the first reference power supply, so as to avoid that the input voltage of the non-inverting input end (+) of the first comparison component U2 is too large to cause damage of the first comparison component U2; the eleventh resistor R11 and the twelfth resistor R12 are used for voltage division of the second reference power supply, so as to avoid that the input voltage of the inverting input end (-) of the second comparison component U3 is too large to cause damage of the second comparison component U3; in addition, the first reference circuit 501 provides the upper limit reference voltage, and the second reference circuit 502 provides the lower limit reference voltage, by changing the first reference power supply Vref1 and the second reference power supply Vref2, the upper limit reference voltage and the lower limit reference voltage can be changed, the current detection range of the protection device can be expanded, and the application scene of the protection device can be widened.

[0097] In some embodiments, as Figure 6As shown, the switch unit 102 can include a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a transistor Q;The first end of the third resistor R3 is connected with the fifth power supply V5, and the second end of the third resistor R3 is connected with the output end of the first comparison component U2, the output end of the second comparison component U3 and the first end of the transistor Q respectively;The first end of the fourth resistor R4 is connected with the sixth power supply V6, and the second end of the fourth resistor R4 is connected with the second end of the transistor Q;The third end of the transistor Q is connected with the first end of the fifth resistor R5 and the input end of the protection unit 1023 respectively, the second end of the fifth resistor R5 is connected with the ground, and the third end of the transistor Q is used to output the initial signal.

[0098] In the embodiment of the utility model, continue to refer to Figure 6 , the switch unit 1022 further includes thirteenth resistor R13 and fourteenth resistor R14;Among them, the first end of thirteenth resistor R13 is connected with the output end of the first comparison component U2, the output end of the second comparison component U3, the second end of the third resistor R3 respectively, the second end of thirteenth resistor R13 is connected with the first end of the transistor Q and the first end of the fourteenth resistor R14 respectively, and the second end of the fourteenth resistor R14 is connected between the second end of the fourth resistor R4 and the second end of the transistor Q.

[0099] In the embodiment of the utility model, for the third resistor R3, it can be called pull-up resistor.For the fifth power supply and the sixth power supply, they can be equal, for example, both are 5V, the fifth power supply and the sixth power supply can also be unequal, according to the actual situation to determine;In addition, for the fifth power supply and the sixth power supply, they can also be added filter capacitor at the corresponding position, to ensure the stability of the fifth power supply and the sixth power supply power supply.

[0100] It should be noted that for thirteenth resistor R13 and fourteenth resistor R14, they can be integrated in the transistor Q, and they are a whole with the transistor Q, and they can also be located outside the transistor Q, such as Figure 7 As shown, thirteenth resistor R13, fourteenth resistor R14 and transistor Q are independent devices.

[0101] In the embodiment of the utility model, transistor Q can be a switching transistor, which can control the on-off of the input signal control circuit. For example, transistor Q can be a field effect transistor (FET), a metal-oxide-semiconductor field-effect transistor (MOSFET), a triode, an insulated gate bipolar transistor (IGBT), and the like, which is not specifically limited.

[0102] In a specific embodiment, taking MOSFET as an example, transistor Q is a P-type MOSFET (referred to as "PMOS tube"), the first end of transistor Q is the gate end of the PMOS tube, the second end of transistor Q is the source end of the PMOS tube, and the third end of transistor Q is the drain end. For the PMOS tube, the gate end is turned on when a low-level signal is inputted, thereby outputting an initial signal.

[0103] In the embodiment of the utility model, when the output ends of the two comparison components both output high-level signals, the output ends of the two comparison components and the third resistor are all high-level, at this time, the two comparison components and the third resistor are not turned on, the first end of the thirteenth resistor is high-level, and the PMOS tube is not turned on. If the output ends of the two comparison components output low-level signals and high-level signals, taking the output end of the first comparison component outputting a low-level signal and the output end of the second comparison component outputting a high-level signal as an example, since the output end of the first comparison component is a low-level signal, that is, the output end of the first comparison component is low, and since the third resistor is high, a loop is formed between the third resistor and the output end of the first comparison component, current flows from high to low, thereby pulling down the voltage of the gate end of the PMOS tube, so that the PMOS tube is turned on. When the PMOS tube is turned on, the PMOS tube outputs an initial signal, thereby indicating that the to-be-tested circuit has an undercurrent or overcurrent fault.

[0104] In the embodiment of the utility model, after the current detection signal Ac is transmitted to the comparison unit 1021, the first comparison component U2 and the second comparison component U3 calculate the current detection signal Ac. When the current detection signal Ac is higher than the upper limit reference voltage or lower than the lower limit reference voltage, the PMOS tube is closed, and the current protection signal Ap is outputted to the MCU through the protection unit, thereby realizing the current protection function of the to-be-tested circuit by the MCU; when the current detection signal Ac is within the upper limit reference voltage and the lower limit reference voltage, it indicates that the to-be-tested circuit is normal, and the MCU does not need to drive the current protection function.

[0105] In this way, through the cooperation of the transistor of the switch unit and each resistor, the transistor can output the initial signal when the first comparison component and the second comparison component judge that the to-be-tested circuit is in the overcurrent or undercurrent state according to the current detection signal, and further make the protection unit output the current protection signal, so that the current protection function of the subsequent circuit is started, and the safety and reliability of the equipment are further improved.

[0106] In some embodiments, as shown in Figure 7 The protection unit 1023 includes an edge trigger component U4 and a sixth resistor R6.

[0107] The first end of the sixth resistor R6 is connected with the third end of the transistor Q and the first end of the fifth resistor R5 respectively, and the second end of the sixth resistor R6 is connected with the clock signal end (CP) of the edge trigger component U4; the power supply end (Vcc) of the edge trigger component U4 and the output end (Q) of the edge trigger component U4 are connected with the seventh power supply V7 respectively, the ground end (GND) of the edge trigger component U4 is connected with the ground, and the output end (Q) of the edge trigger component U4 is further used for outputting the current protection signal when detecting that the level state of the clock signal end is reversed.

[0108] In the embodiment of the utility model, as shown in Figure 7 The protection unit 1023 can further include a thirteenth capacitor C13, a fourteenth capacitor C14 and a fifteenth resistor R15; wherein the first end of the thirteenth capacitor C13 is connected with the output end (Q) of the edge trigger component U4 and the seventh power supply V7, and the second end of the thirteenth capacitor C13 is grounded; the fifteenth resistor R15 is connected between the ninth power supply V9 and the data input end (D) of the edge trigger component U4; the fourteenth capacitor C14 is connected between the reset end ( / MR) of the edge trigger component U4 and the eighth power supply V8. Here, the thirteenth capacitor C13 and the fourteenth capacitor C14 are used for filtering the corresponding power supply or output signal to ensure that a stable power supply or an interference-free output signal is provided. Here, the seventh power supply, the eighth power supply and the ninth power supply can be equal, for example, all are 5V, and the seventh power supply, the eighth power supply and the ninth power supply can also be unequal, which is determined according to the actual situation.

[0109] In the embodiment of the utility model, the edge trigger component U4 can be called an edge trigger, which is a basic storage unit in a digital circuit, capable of storing a binary information and changing its output state when the rising edge or falling edge of a clock signal arrives. The working principle of the edge trigger component U4 is based on the synchronous relationship between the clock signal at the clock signal end and the input signal at the data input end. During the stable period of the clock signal at the clock signal end (i.e. the clock signal is 0 or 1), the input signal at the data input end cannot change the state of the edge trigger component U4. Only when the clock signal at the clock signal end jumps as agreed (such as from 0 to 1 or from 1 to 0), the trigger will change its state according to the input signal at that time.

[0110] In the embodiment of the utility model, if the transistor in the switch unit is not turned on and there is no output, it can be understood that the initial signal output by the transistor is 0. After the transistor in the switch unit is turned on, the level signal of the initial signal changes, for example, from 0 to 1. At this time, the clock signal end (CP) of the edge trigger component U4 receives the level change of the initial signal, the level state of the clock signal end of the edge trigger component U4 flips, and the output end (Q) of the edge trigger component U4 outputs the current protection signal, that is, the edge trigger component will perform state conversion according to the initial signal state to output the current protection signal.

[0111] In the embodiment of the utility model, the sixth resistor R6 is used for current limiting to avoid the clock signal end (CP) of the edge trigger component U4 inputting a voltage that is too large and causing the edge trigger component U4 to be damaged.

[0112] In the embodiment of the utility model, considering that the overcurrent or undercurrent occurs for a short time in some scenarios, the edge trigger component outputs the current protection signal at the moment when it detects that the level state of the initial signal flips, so that the overcurrent or undercurrent fault phenomenon can also be accurately captured, and the overcurrent protection function is triggered quickly when the fault phenomenon occurs, further improving the safety and reliability of the equipment.

[0113] In some embodiments, the protection unit further comprises an anti-reverse component, wherein: the first end of the anti-reverse component is connected with the output end of the edge trigger component, the second end of the anti-reverse component is connected with the output port, and the output port is used for outputting the current protection signal.

[0114] In the embodiment of the utility model, the anti-reverse component is used for preventing the reverse flow of current, and can be a diode in a normal case. The diode has unidirectional conductivity and only allows current to flow in one direction. In a specific embodiment, as shown in Figure 7 , the protection unit 1023 can include a diode D, where the diode D is an anti-reverse component, the first end of the anti-reverse component is the anode end of the diode D, the second end of the anti-reverse component is the cathode end of the diode D, and is used for preventing the reverse flow of current.

[0115] That is, the anti-reverse component can protect against reverse current flow, thereby protecting the elements in the circuit from damage and improving the safety of the circuit.

[0116] In some embodiments, as shown in Figure 7 The protection unit 1023 further includes a voltage dividing component 701, and the voltage dividing component 701 includes a seventh resistor R7 and an eighth resistor R8, wherein: a first end of the seventh resistor R7 is connected to a second end of the anti-reverse device, a second end of the eighth resistor R7 is connected to the ground, and a second end of the seventh resistor R7 and a first end of the eighth resistor R8 are respectively connected to the output port.

[0117] In the embodiment of the utility model, the voltage dividing component 701 can protect the subsequent circuit, for example, when the voltage output by the edge trigger component U4 is too large, the voltage dividing component 701 can share part of the voltage, thereby preventing the subsequent circuit from being damaged due to overvoltage.

[0118] In the embodiment of the utility model, for Figure 8 The resistance values of the various resistors in the above embodiment can be set according to specific conditions. For example, the resistance values of the ninth resistor to the twelfth resistor can be two hundred kilo-ohms, and the resistance values of the third resistor to the eighth resistor and the fifteenth resistor can be one kilo-ohm.

[0119] In another embodiment of the utility model, the protection device based on the foregoing embodiment, Figure 8 A processing flow diagram of a protection device according to an embodiment of the utility model is provided. As shown in Figure 4 The processing flow can be completed by the current detection circuit 101 and the current protection circuit 102 in cooperation and output through the output port.

[0120] In the embodiment of the utility model, the circuit to be tested can be referred to as a charging loop, which includes a DC / DC converter. The current detection circuit 101 detects the current in the charging loop and outputs a current detection signal, and the current protection circuit 102 receives the current detection signal, judges according to the current detection signal, and outputs the detection result (i.e. current protection signal) through the output port, thereby realizing overcurrent or undercurrent protection of the charging loop, avoiding the failure of the DC / DC converter in the charging loop due to overcurrent or undercurrent phenomenon, and causing safety problems.

[0121] In the embodiment of the utility model, the current detection circuit 101 realizes the current detection function through the SHUNT resistor, transmits the obtained voltage value to the current protection circuit, completes the bidirectional judgment of the voltage value through the comparison unit, generates the current protection signal through the protection unit, and then transmits the current protection signal to the MCU, so that the MCU drives the current protection function to realize the current protection function.

[0122] In some embodiments, as shown in the foregoing Figure 4 , the current detection circuit comprises a detection resistor Rt, a first resistor R1, a second resistor R2, a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, a first power supply V1, a second power supply V2 and an operational amplifier component OPA. Here, the detection resistor Rt is a SHUNT resistor, the first power supply V1 can be 2.5V, the second power supply V2 can be 5V, and the connection relationship of each device is specifically refer to Figure 7 .

[0123] In the embodiment of the utility model, SHUNT resistor, first resistor R1, second resistor R2, first inductor L1, second inductor L2, first capacitor C1, second capacitor C2, third capacitor C3, fourth capacitor C4 constitute filter unit. Operational amplifier component U1, fifth capacitor C5, sixth capacitor C6 and seventh capacitor C7 constitute amplification unit.

[0124] In the embodiment of the utility model, when the DC / DC converter in the charging loop starts to work, the SHUNT resistor is used to measure the current of the charging loop. Since the SHUNT resistor has a very low resistance value, when the current passes through the entire circuit, part of the current passes through the SHUNT resistor, and the other part of the current passes through other circuit components. According to the voltage drop across the SHUNT resistor, the first current signal of the entire charging loop is detected using Ohm's law. And the first current signal generated by the SHUNT resistor is filtered by the filter unit, then amplified by the operational amplifier component to obtain the current detection signal, and the current detection signal is transmitted to the current protection circuit for judgment.

[0125] In some embodiments, as shown in the foregoing Figure 7 , the current protection circuit comprises a first comparison component U2, a second comparison component U3, a transistor Q, an edge trigger component U4, a diode D, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13, a fourteenth capacitor C14, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a thirteenth resistor R13, a fourteenth resistor R14 and a fifteenth resistor R15. Here, the transistor Q is a PMOS transistor; the first power supply V1 to the ninth power supply V9 can be 5V. In addition, the connection relationship of each component is specifically refer to Figure 9 .

[0126] In the embodiment of the utility model, first comparison component U2, second comparison component U3, eighth capacitor C8, ninth capacitor C9, tenth capacitor C10, eleventh capacitor C11 and twelfth capacitor C12 constitute comparison unit, third resistance R3, fourth resistance R4, fifth resistance R5, thirteenth resistance R13, fourteenth resistance R14 and transistor Q constitute switch unit, sixth resistance R6, seventh resistance R7 eighth resistance R8, fifteenth resistance R15, thirteenth capacitor C13, fourteenth capacitor C14 and diode D constitute protection unit.

[0127] In the embodiment of the utility model, after current detection signal is transmitted to current protection circuit, first comparison component U2 and second comparison component U3 in comparison unit calculate current detection signal, when current detection signal is higher than voltage upper limit value (i.e. upper limit reference voltage) or lower than voltage lower limit value (i.e. lower limit reference voltage), PMOS pipe closes, and current protection signal is outputted to micro control MCU through edge trigger component operation, and the current protection function in charging loop is realized by MCU;When current detection signal is in set voltage upper limit value and voltage lower limit value, then it shows that the charging loop is normal, and the current protection function does not need MCU drive.

[0128] In the embodiment of the utility model, the noninverting input terminal of the first comparator is connected with the first reference circuit, and the inverting input terminal of the second comparator is connected with the second reference circuit;Here, the first reference circuit comprises ninth resistance R9, tenth resistance R10 and first reference power supply Vref1, the second reference circuit comprises eleventh resistance R11, twelfth resistance R12 and second reference power supply Vref1, and the first reference circuit is used for providing upper limit reference voltage, and the second reference circuit is used for providing lower limit reference voltage.

[0129] In the embodiment of the utility model, since there are two input terminals (noninverting input terminal and inverting input terminal) and an output terminal in the comparison component, taking the first comparison component as an example, if the voltage of the noninverting input terminal of the first comparator is greater than the voltage of the inverting input terminal of the first comparator, i.e. + >U1 - , the output terminal of the first comparison component outputs high level signal, i.e. OUT =U H ; if the voltage of the noninverting input terminal of the first comparison component is less than the voltage of the inverting input terminal of the first comparison component, i.e. + <U1 - , the output terminal of the first comparison component outputs low level signal, i.e. OUT =U L . Therefore, in the embodiment of the utility model, the overcurrent or undercurrent phenomenon in the charging loop can be judged by two comparison components (i.e. two comparators), so as to realize the current protection function of the to-be-tested circuit, and the specific implementation is as follows:

[0130] 1, overcurrent: when the voltage value of the current detection signal is higher than the upper limit value of the voltage, the output end of the first comparison component outputs a low level signal, and the output end of the second comparison component outputs a high level signal, at this time, the PMOS tube is pulled down, the PMOS tube is driven to close, and the subsequent protection circuit is opened. For example, the upper limit value of the voltage is 7V, and the lower limit value of the voltage is 2V, when the current detection signal is 8V, the PMOS tube is closed to make the protection unit output the current protection signal to the MCU, and the subsequent protection circuit is driven by the MCU;

[0131] 2, undercurrent: when the voltage value of the current detection signal is lower than the lower limit value of the voltage, the output end of the first comparison component outputs a high level signal, and the output end of the second comparison component outputs a low level signal, at this time, the PMOS tube is pulled down, the PMOS tube is driven to close, and the subsequent protection circuit is opened. For example, the upper limit value of the voltage is 7V, and the lower limit value of the voltage is 2V, when the current detection signal is 1.5V, the PMOS tube is closed to make the protection unit output the current protection signal to the MCU, and the subsequent protection circuit is driven by the MCU;

[0132] 3, normal current: when the voltage value of the current detection signal is between the upper limit value of the voltage and the lower limit value of the voltage, the output end of the first comparison component outputs a high level signal, and the output end of the second comparison component outputs a high level signal, at this time, the PMOS tube is not changed, the PMOS tube is always open, and the charging circuit does not exist overcurrent or undercurrent phenomenon. For example, the upper limit value of the voltage is 7V, and the lower limit value of the voltage is 2V, when the current detection signal is 5V, the subsequent protection circuit does not need to be opened.

[0133] The embodiment of the utility model provides a protection device, through the above -mentioned embodiment to the specific implementation of preceding embodiment has carried out detailed elaboration, can see from it, the current detection and bidirectional overcurrent protection circuit are designed, realize current detection function through SHUNT resistance, transmit the voltage value obtained to the current protection circuit, judge the voltage value through the comparator, so that when the charging circuit exists undercurrent or overcurrent fault, drive the subsequent protection circuit, to realize the current protection function. That is to say, the vehicle charger can realize protection under overcurrent or undercurrent, thereby improving the safety and reliability of the equipment, and making the use scene of the protection device extensive.

[0134] In another embodiment of the utility model, Figure 9 The utility model provides a kind of composition structure schematic diagram of charging device for the embodiment of the utility model. As Figure 10 As shown, the charging device 90 includes the protection device 10 and the to-be-tested circuit 901 as described in any one of the preceding embodiments.

[0135] In the embodiment of the utility model, the charging device 90 can be a vehicle charger, wherein the vehicle charger usually uses a two-stage conversion structure, the vehicle charger rectifies alternating current through an AC / DC converter first, then connects the rectified direct current to a DC / DC converter to adjust the direct current voltage, and finally inputs the adjusted direct current to a load, and the protection device 10 is used for undercurrent or overcurrent detection of the vehicle charger to ensure the safety of the vehicle charger.

[0136] In another embodiment of the utility model, Figure 10 The utility model provides a kind of composition structure schematic diagram of electric drive equipment for the embodiment of the utility model. As ​ Indicated, electric drive equipment 100 includes charging device 90 as described in the foregoing embodiment.

[0137] In the embodiment of the utility model, electric drive equipment 100 is the technical device that converts electric energy into mechanical energy, is used to drive various mechanical equipment, and it can adjust power output according to external instruction, and converts electric energy into mechanical energy to drive equipment to run. Here, electric drive equipment 100 can include charging device 90, and protection device 10 is included in charging device 90, and protection device 10 is used for undercurrent or overcurrent detection to the circuit to be measured, and the circuit to be measured 10 can be charging circuit in electric drive equipment. Exemplarily, electric drive equipment 100 can be new energy vehicle, ship, aircraft and the like, in addition, new energy vehicle can be pure electric vehicle, plug-in hybrid electric vehicle, electric motorcycle and the like, and this is not specifically limited.

[0138] In an embodiment, taking electric drive equipment 100 as new energy vehicle as an example, new energy vehicle includes charging device 90. Taking charging device 90 as vehicle charger as an example, vehicle charger can be located in new energy vehicle, and the two are a whole;Or vehicle charger can be located outside new energy vehicle, and the two are two independent devices.

[0139] The utility model provides a kind of electric drive equipment, electric drive equipment includes charging device, and charging device includes protection device, using detection resistance can realize the current of the circuit to be measured to carry out rapid detection, shorten the current detection time of protection device, to trigger current protection function quickly when the current fault of the circuit to be measured appears;And using comparison unit carries out overcurrent or undercurrent judgment to current detection signal, not only can realize the current protection function under the overcurrent or undercurrent state of the circuit to be measured, but also can widen the application scene of protection device, improve the security and reliability of equipment;In addition, considering that the time of overcurrent or undercurrent occurs under part scene is shorter, protection unit is used to output current protection signal when the level state of initial signal is detected to reverse moment, to accurately capture the fault phenomenon of overcurrent or undercurrent occurrence, and overcurrent protection function is triggered quickly when fault phenomenon appears, further improve the security and reliability of equipment.

[0140] It should be noted that in the utility model, the terms "comprising", "including" or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, product or device that includes a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, product or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method, product or device that includes the element.

[0141] In several embodiments provided by the utility model, it should be understood that the disclosed system, device and method can be implemented in other ways. The above-described device embodiments are only illustrative, for example, the division of units is only a logical function division, and actual implementation can have another division mode, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed components can be through some interface, indirect coupling or communication connection of device or unit, which can be electrical, mechanical or other forms.

[0142] The units described as separate components above can or can not be physically separate, and the components displayed as units can or can not be physical units; they can be located in one place, or distributed on multiple network units; part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme. In addition, in each embodiment of the utility model, each functional unit can be integrated in one processing unit, or each unit can be separately as a unit, or two or more units can be integrated in one unit; the integrated unit can be realized in the form of hardware, or in the form of hardware plus software functional unit.

[0143] The above is only a preferred embodiment of the utility model, and is not used to limit the protection scope of the utility model, and any modification, equivalent replacement and improvement made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A protection device, characterized in that The protection device comprises a current detection circuit and a current protection circuit, wherein: The current detection circuit comprises a detection resistor, and the detection resistor is connected in series in a circuit to be detected; the current detection circuit is configured to generate a current detection signal based on the detection resistor; The current protection circuit comprises a comparison unit, a switching unit and a protection unit; an input end of the comparison unit is connected with an output end of the current detection circuit; an output end of the comparison unit is connected with an input end of the switching unit; an output end of the switching unit is connected with an input end of the protection unit; The current protection circuit is configured to receive the current detection signal through the input end of the comparison unit; when a voltage value of the current detection signal is higher than an upper limit reference voltage or the voltage value of the current detection signal is lower than a lower limit reference voltage, an initial signal is generated through the switching unit; and when the protection unit detects that a level state of the initial signal is reversed, a current protection signal is outputted through the protection unit.

2. The protection device according to claim 1, characterized in that The current detection circuit further comprises a filtering unit and an amplifying unit; wherein: An input end of the filtering unit is connected at both ends of the detection resistor, and is configured to filter a first current signal generated by the detection resistor to generate a second current signal; The amplifying unit is connected with an output end of the filtering unit, and is configured to amplify the second current signal to generate the current detection signal.

3. The protection device according to claim 2, characterized in that The filtering unit comprises a differential mode filtering component, a common mode filtering component, a first filtering component and a current limiting component, wherein: The differential mode filtering component comprises a first capacitor; the common mode filtering component comprises a second capacitor and a third capacitor; the first filtering component comprises a fourth capacitor, a first inductor and a second inductor; and the current limiting component comprises a first resistor and a second resistor; A first end of the first capacitor is connected with a first end of the detection resistor, a first end of the second capacitor and a first end of the first inductor respectively; a second end of the first capacitor is connected with a second end of the detection resistor, a second end of the third capacitor and a first end of the second inductor; a first end of the first inductor is also connected with the first end of the second capacitor; a second end of the first inductor is connected with a first end of the first resistor; a first end of the third capacitor is connected with a second end of the second capacitor and a first output end of the circuit to be detected respectively; a second end of the third capacitor is also connected with the first end of the second inductor; a second end of the second inductor is connected with a first end of the second resistor; a first end of the fourth capacitor is connected with a second end of the first resistor; and a second end of the fourth capacitor is connected with a second end of the second resistor.

4. The protection device according to claim 3, characterized in that The amplifying unit comprises an operational amplifying component; wherein: An inverting input terminal of the operational amplification component is connected with a second terminal of the first resistor and a first terminal of the fourth capacitor respectively, a non-inverting input terminal of the operational amplification component is connected with a second terminal of the second resistor and a second terminal of the fourth capacitor respectively, a reference terminal of the operational amplification component is connected with a first power supply, a power supply terminal of the operational amplification component is connected with a second power supply, a ground terminal of the operational amplification component is connected with the ground, and an output terminal of the operational amplification component is used to output the current detection signal.

5. The protection device according to any one of claims 1 to 4, characterized in that, The comparison unit comprises a first comparison component and a second comparison component; wherein: A non-inverting input terminal of the first comparison component is connected with a first reference circuit, an inverting input terminal of the second comparison component is connected with a second reference circuit, an inverting input terminal of the first comparison component and a non-inverting input terminal of the second comparison component are connected with an output terminal of the current detection circuit respectively, and an output terminal of the first comparison component and an output terminal of the second comparison component are connected with an input terminal of the switch unit respectively; a power supply terminal of the first comparison component is connected with a third power supply, a ground terminal of the first comparison component is connected with the ground, a power supply terminal of the second comparison component is connected with a fourth power supply, and a ground terminal of the second comparison component is connected with the ground.

6. The protection device according to claim 5, characterized in that The switch unit comprises a third resistor, a fourth resistor, a fifth resistor and a transistor; wherein: A first terminal of the third resistor is connected with a fifth power supply, a second terminal of the third resistor is connected with the output terminal of the first comparison component, the output terminal of the second comparison component and a first terminal of the transistor respectively; a first terminal of the fourth resistor is connected with a sixth power supply, and a second terminal of the fourth resistor is connected with a second terminal of the transistor; a third terminal of the transistor is connected with a first terminal of the fifth resistor and an input terminal of the protection unit respectively, a second terminal of the fifth resistor is connected with the ground, and the third terminal of the transistor is used to output the initial signal.

7. The protection device according to claim 6, characterized in that The protection unit comprises an edge trigger component and a sixth resistor; wherein: A first terminal of the sixth resistor is connected with the third terminal of the transistor and the first terminal of the fifth resistor respectively, and a second terminal of the sixth resistor is connected with a clock signal terminal of the edge trigger component; a power supply terminal of the edge trigger component and an output terminal of the edge trigger component are connected with a seventh power supply respectively, a ground terminal of the edge trigger component is connected with the ground, and the output terminal of the edge trigger component is also used to output the current protection signal when detecting that a level state of the clock signal terminal is reversed.

8. The protection device according to claim 7, characterized in that The protection unit further comprises an anti-reverse component, wherein: A first terminal of the anti-reverse component is connected with the output terminal of the edge trigger component, a second terminal of the anti-reverse component is connected with an output port, and the output port is used to output the current protection signal.

9. The protection device according to claim 8, characterized in that The protection unit further comprises a voltage division component, and the voltage division component comprises a seventh resistor and an eighth resistor, wherein: A first terminal of the seventh resistor is connected with the second terminal of the anti-reverse component; A second terminal of the eighth resistor is connected with the ground, and a second terminal of the seventh resistor and a first terminal of the eighth resistor are connected with the output port respectively.

10. The protection device of claim 5, wherein, The first reference circuit comprises a ninth resistor, a tenth resistor and a first reference power supply, and the second reference circuit comprises an eleventh resistor, a twelfth resistor and a second reference power supply, wherein: In the first reference circuit, a first end of the ninth resistor is connected with the first reference power supply, a second end of the ninth resistor and a first end of the tenth resistor are respectively connected with a non-inverting input end of a first comparison component, and a second end of the tenth resistor is connected with the ground; In the second reference circuit, a first end of the eleventh resistor is connected with the second reference power supply, a second end of the eleventh resistor and a first end of the twelfth resistor are respectively connected with an inverting input end of a second comparison component, and a second end of the twelfth resistor is connected with the ground.

11. A charging device, characterized by The charging device comprises a to-be-tested circuit and the protection device according to any one of claims 1 to 10.

12. An electric drive device, characterized by The electrically-driven equipment comprises the charging device according to claim 11.

Images