Interface identification circuit based on current mirror and battery

Abstract

The utility model relates to the technical field of lithium ion battery protection, and discloses an interface identification circuit based on a current mirror and a battery. The interface identification circuit comprises a constant current source unit circuit, the positive terminal of the constant current source unit circuit is electrically connected with the first output end of a current mirror unit circuit, and the negative terminal of the constant current source unit circuit is grounded; a first input end of the current mirror unit circuit is electrically connected with a positive electrode of a battery, a second input end of the current mirror unit circuit is electrically connected with an external interface of the battery to be identified, a second output end of the current mirror unit circuit is electrically connected with a first end of a divider resistor and a voltage input end of the conversion unit circuit, and a second end of the divider resistor is grounded. And the conversion level output end of the conversion unit circuit is electrically connected with the MCU of the battery management system. According to the utility model, the identification sensitivity of the external interface of the battery can be adjusted by adjusting the resistance and the divider resistance in the current mirror unit circuit, so that the false identification action of the circuit is effectively avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium ion battery protection technical field especially, relates to an interface identification circuit and battery based on current mirror. BACKGROUND

[0002] In the practical application of the battery, the connection state of the external connector of the battery external interface needs to be identified, which requires a functional circuit to determine whether a pin or signal has been connected to the discharge positive electrode or a specific voltage. Figure 1 As shown in the figure, the voltage input by the Short_H pin (the pin to be identified) of the battery interface identification circuit is divided by the resistance R2', and then identified by the transistor Q1'. When the Short_H pin input is high, the base voltage of the transistor Q1' is high, the transistor Q1' is turned on, and the MCU_IO port (the identification signal input interface of the master control chip of the battery management system) is pulled low.

[0003] However, in the actual use environment, the battery external interface may be contaminated by water, snow, leaves and other foreign matters, resulting in an equivalent connection resistance between the Short_H pin and the discharge positive electrode, which causes the battery interface identification circuit to misidentify. In addition, the working of the transistor may be affected by the environmental temperature, which also causes the battery interface identification circuit to misidentify. Moreover, when the battery external interface is connected, the BMS (Battery Management System) still has power consumption after shutdown.

[0004] The above information is given as background information only to assist with an understanding of the present disclosure, and does not constitute a determination or acknowledgement that any of the above information can be used as prior art with respect to the present disclosure. SUMMARY

[0005] The utility model aims at providing an interface identification circuit and battery based on current mirror to solve or at least partially solve the technical problems existing in the prior art.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] In a first aspect, the utility model provides an interface identification circuit based on current mirror, which comprises a constant current source unit circuit, a first output end of a current mirror unit circuit is electrically connected to the positive connection end of the constant current source unit circuit, and the negative connection end of the constant current source unit circuit is grounded.

[0008] The first input end of the current mirror unit circuit is electrically connected with the positive pole of the battery, the second input end of the current mirror unit circuit is electrically connected with the external interface of the battery to be identified, the second output end of the current mirror unit circuit is electrically connected with the first end of the voltage dividing resistor and the voltage input end of the conversion unit circuit respectively, the second end of the voltage dividing resistor is grounded, and the conversion level output end of the conversion unit circuit is electrically connected with the MCU of the battery management system.

[0009] The first output end of the current mirror unit circuit is used for outputting a constant current I1, and the current outputted by the second output end of the current mirror unit circuit is I2, and I1 / I2 is in linear relationship with the resistance value of the connecting resistor of the external interface of the battery.

[0010] Optionally, the current mirror unit circuit comprises a first branch, the first branch comprises a resistor R4 and a switch tube Q5, the first end of the resistor R4 is the first input end of the current mirror unit circuit, the second end of the resistor R4 is electrically connected with the positive connection end of the switch tube Q5, the negative connection end of the switch tube Q5 is the first output end of the current mirror unit circuit, and the negative connection end and the control end of the switch tube Q5 are electrically connected.

[0011] The current mirror unit circuit is provided with at least one second branch, the second branch comprises a mirror resistor and a mirror switch tube, the first end of the mirror resistor is the second input end of the current mirror unit circuit, the second end of the mirror resistor is electrically connected with the positive connection end of the mirror switch tube, the control end of the mirror switch tube is electrically connected with the control end of the switch tube Q5, and the negative connection end of the mirror switch tube is a second output end of the current mirror unit circuit.

[0012] The resistance value of the resistor R4 is i, the resistance value of the mirror resistor is j, the resistance value of the connecting resistor is k, and the relationship between the current I2 and the resistance value of the connecting resistor of the external interface of the battery is expressed as:

[0013] I2=I1*i / (j+k).

[0014] Optionally, the control end of the mirror switch tube and the control end of the switch tube Q5 are further electrically connected with a current limiting resistor.

[0015] The first end of the resistor R4 and the positive pole of the battery are further electrically connected with a diode D1, and the external interface of the battery and the first end of the mirror resistor are further electrically connected with a mirror diode.

[0016] The positive pole of the diode D1 is used for electrically connecting with the positive pole of the battery, and the positive pole of the mirror diode is used for electrically connecting with the external interface of the battery.

[0017] Optionally, the second output end of the current mirror unit circuit and the voltage input end of the conversion unit circuit are further electrically connected with a temperature compensation unit circuit.

[0018] The temperature compensation unit circuit comprises a temperature compensation diode, a first temperature compensation resistor and a second temperature compensation resistor; the positive pole of the temperature compensation diode is electrically connected to the first end of the voltage dividing resistor and the first end of the first temperature compensation resistor respectively, the negative pole of the temperature compensation diode is electrically connected to the first end of the second temperature compensation resistor, the second end of the second temperature compensation resistor is grounded, and the second end of the first temperature compensation resistor is electrically connected to the voltage input end of the conversion unit circuit 40.

[0019] Optionally, the conversion unit circuit comprises a plurality of level conversion branches electrically connected to the second branches respectively.

[0020] The level conversion branch comprises a conversion switch tube and a conversion resistor; the control end of the conversion switch tube is a voltage input end of the conversion unit circuit, the first end of the conversion resistor is electrically connected to a reference power supply VCC inside the battery management system, the second end of the conversion resistor is electrically connected to the positive connection end of the conversion switch tube, and the negative connection end of the conversion switch tube is grounded.

[0021] The second end of the conversion resistor is the conversion level output end of the conversion unit circuit.

[0022] Optionally, the first output end of the current mirror unit circuit is further electrically connected to the first end of a resistor R3, the second end of the resistor R3 is electrically connected to the positive connection end of the constant current source unit circuit, the second output end of the current mirror unit circuit is further electrically connected to the first end of a protection resistor, and the second end of the protection resistor is electrically connected to the first end of the voltage dividing resistor.

[0023] Optionally, the constant current source unit circuit comprises a resistor R7, a switch tube Q2 and a resistor R10.

[0024] The first end of the resistor R7 is electrically connected to the reference power supply VCC inside the battery management system, the second end of the resistor R7 is electrically connected to the control end of the switch tube Q2, the positive connection end of the switch tube Q2 is electrically connected to the second end of the resistor R3, the negative connection end of the switch tube Q2 is electrically connected to the first end of the resistor R10, and the second end of the resistor R10 is grounded.

[0025] Optionally, the switch tube Q5 and the mirror switch tube are PNP triodes of the same type, and the switch tube Q2 and the conversion switch tube are NPN triodes.

[0026] In the second aspect, the utility model provides a kind of battery, comprising battery management system, the battery management system is electrically connected with interface identification circuit, the interface identification circuit uses the interface identification circuit based on current mirror as described above.

[0027] Optionally, the battery is a lithium battery pack.

[0028] Compared with the prior art, the utility model has the following beneficial effects:

[0029] The interface recognition circuit based on the current mirror has the advantages that the resistance value change of the connecting resistance of the battery external interface is converted into current change through the constant current source unit circuit and the current mirror unit circuit, the working voltage range is widened, the working of the circuit is not affected by the change of B+, the identification sensitivity of the battery external interface is adjusted by adjusting the resistance and the voltage dividing resistance in the current mirror unit circuit, the misidentification of the circuit is effectively avoided, and the overall circuit is started or stopped working together with the battery management system through the constant current source unit circuit, and the situation that power consumption is generated when the machine is shut down is avoided.

[0030] The present application has other characteristics and advantages, which will be apparent from the accompanying drawings and the following detailed description, or will be described in detail in the accompanying drawings and the following detailed description, which are incorporated herein, and which are collectively used to explain the specific principles of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0032] Figure 1 is a schematic diagram of a battery interface recognition circuit in the prior art.

[0033] Figure 2 is a structural principle diagram of an interface recognition circuit based on a current mirror provided by the embodiment of the present application.

[0034] Figure 3 is a circuit structure diagram when the interface recognition circuit based on the current mirror provided by the embodiment of the present application works.

[0035] Figure 4 is a circuit structure diagram when another interface recognition circuit based on the current mirror provided by the embodiment of the present application works. DETAILED DESCRIPTION

[0036] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0037] The term "embodiment" is mentioned herein means that the specific features, structures, or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit the independence or association between other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the technical features mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.

[0038] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments, and is not intended to limit the present application.

[0039] In the description of the present application, the phrase "and / or" is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " herein generally represents that the associated objects before and after are a "or" logical relationship.

[0040] In the present application, the terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary and secondary or order relationship between the entities or operations.

[0041] In the present application, without more limitation, the "includes", "contains", "has" or other similar expressions used in the sentence are intended to cover non-exclusive inclusion, and these expressions do not exclude the presence of other elements in the process, method or product including the described elements, so that the process, method or product including a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include the elements inherent to such process, method or product.

[0042] As the same as the understanding in the "Guidelines for Examination", in the present application, the expressions such as "greater than", "less than", "exceed" are understood as not including the number; the expressions such as "above", "below", "within" are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times", etc., unless otherwise explicitly limited.

[0043] In the description of the embodiments of the present application, the spatially relative terms, such as "central", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship shown in the specific embodiment or the accompanying drawings, and are only used to facilitate the description of the specific embodiments of the present application or to facilitate the understanding of the reader, and do not indicate or imply that the indicated device or component must have a particular position, a particular orientation, or be constructed or operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0044] Unless otherwise expressly specified or limited, the terms "mount", "connect", "connection", "fixed", "set", and the like used in the description of the embodiments of the present application should be interpreted broadly. For example, the "connection" can be a fixed connection, or a detachable connection, or an integral setting; it can be a mechanical connection, or an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium; it can be a communication or interaction relationship between two elements. For those skilled in the art to which the present application belongs, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0045] Embodiment one:

[0046] Please refer to Figure 2 , Figure 2 is a structure principle diagram of an interface recognition circuit based on a current mirror provided by the embodiment of the present application;

[0047] As Figure 2 shown, the interface recognition circuit comprises a constant current source unit circuit 20, the positive connection end of the constant current source unit circuit 20 is electrically connected with the first output end of the current mirror unit circuit 10, and the negative connection end of the constant current source unit circuit 20 is grounded;

[0048] The first input end of the current mirror unit circuit 10 is electrically connected with the positive electrode B+ of a battery, the second input end of the current mirror unit circuit 10 is electrically connected with the external interface of the battery to be recognized, the second output end of the current mirror unit circuit 10 is respectively electrically connected with the first end of a resistor R11 and the voltage input end of a conversion unit circuit 40, the second end of the resistor R11 is grounded, and the conversion level output end of the conversion unit circuit 40 is electrically connected with the MCU of a battery management system;

[0049] Among them, the first output end of the current mirror unit circuit 10 is used for outputting a constant current I1, the current outputted by the second output end of the current mirror unit circuit 10 is I2, and I1 / I2 has a linear relationship with the resistance value of the connection resistance of the external interface of the battery.

[0050] As an optional implementation, as shown in Figure 2 The current mirror unit circuit 10 includes a resistor R4 and a switch tube Q5, and a resistor R2 and a switch tube Q3 which are mirror arranged with the resistor R4 and the switch tube Q5;

[0051] The first end of the resistor R4 is further electrically connected with a diode D1, and the first end of the resistor R2 is further electrically connected with a diode D2; the positive electrode of the diode D1 is used for electrically connecting the positive electrode B+ of the battery, the positive electrode of the diode D2 is used for electrically connecting the external interface Short_H of the battery to be identified, the negative connection end of the switch tube Q5 is the first output end of the current mirror unit circuit 10, and the negative connection end of the switch tube Q3 is the second output end of the current mirror unit circuit 10; the diode D2 and the diode D1 are protection devices for preventing the interface static electricity from damaging the switch tubes Q5 and Q3.

[0052] Specifically, the negative electrode of the diode D1 is electrically connected with the first end of the resistor R4, the second end of the resistor R4 is electrically connected with the positive connection end of the switch tube Q5, and the negative connection end and the control end of the switch tube Q5 are electrically connected; the negative electrode of the diode D2 is electrically connected with the first end of the resistor R2, the second end of the resistor R2 is electrically connected with the positive connection end of the switch tube Q3, and the control end of the switch tube Q3 is electrically connected with the control end of the switch tube Q5 through the current limiting resistor R1.

[0053] Please continue to refer to Figure 3 , Figure 3 is a circuit structure diagram when the interface recognition circuit based on the current mirror works;

[0054] The resistance value of the resistor R4 is i, the resistance value of the resistor R2 is j, the resistance value of the connecting resistor RM1 is k, and the relationship between the current I2 and the resistance value of the connecting resistor of the battery external interface is expressed as:

[0055] I2=I1*i / (j+k).

[0056] As shown in Figure 3 When the Short_H and the B+ are effectively connected, the RM1 is equivalent to 0 ohm, and the I2 becomes large; when the Short_H and the B+ are misconnected, the RM1 becomes large, and the I2 becomes small; when the Short_H and the B+ are not connected, the RM1 is infinite, and the I2 is 0.

[0057] Specifically, the second output end of the current mirror unit circuit 10 and the voltage input end of the conversion unit circuit 40 are further electrically connected with the temperature compensation unit circuit 30;

[0058] The temperature compensation unit circuit 30 comprises a diode D3, a resistor R9 and a resistor R12; the positive pole of the diode D3 is electrically connected to the first end of the resistor R11 and the first end of the resistor R9 respectively, the negative pole of the diode D3 is electrically connected to the first end of the resistor R12, the second end of the resistor R12 is grounded, and the second end of the resistor R9 is electrically connected to the voltage input end of the conversion unit circuit 40.

[0059] Specifically, the conversion unit circuit 40 comprises a switch tube Q4 and a resistor R6; the control end of the switch tube Q4 is the voltage input end of the conversion unit circuit 40, the first end of the resistor R6 is electrically connected to the reference power supply VCC inside the battery management system, the second end of the resistor R6 is electrically connected to the positive connection end of the switch tube Q4, and the negative connection end of the switch tube Q4 is grounded.

[0060] The second end of the resistor R6 is the conversion level output end MCU_IO of the conversion unit circuit 40.

[0061] Specifically, the first output end of the current mirror unit circuit 10 is further electrically connected to the first end of the resistor R3, the second end of the resistor R3 is electrically connected to the positive connection end of the constant current source unit circuit 20, the second output end of the current mirror unit circuit 10 is further electrically connected to the first end of the resistor R8, and the second end of the resistor R8 is electrically connected to the first end of the resistor R11.

[0062] Specifically, the constant current source unit circuit 20 comprises a resistor R7, a switch tube Q2 and a resistor R10.

[0063] The first end of the resistor R7 is electrically connected to the reference power supply VCC inside the battery management system, the second end of the resistor R7 is electrically connected to the control end of the switch tube Q2, the positive connection end of the switch tube Q2 is electrically connected to the second end of the resistor R3, the negative connection end of the switch tube Q2 is electrically connected to the first end of the resistor R10, and the second end of the resistor R10 is grounded.

[0064] In the embodiment, the switch tube Q5 and the switch tube Q3 are PNP triodes of the same type, and the switch tube Q2 and the switch tube Q4 are NPN triodes.

[0065] The interface recognition circuit based on the current mirror provided in the embodiment can convert the resistance value change of the connection resistor RM1 of the external interface of the battery into the current I2 change through the constant current source unit circuit 20 and the current mirror unit circuit 10, avoid the influence of the B+ change on the working of the circuit, and widen the working voltage range.

[0066] The whole circuit can be started or stopped working together with the BMS by taking the VCC as the base voltage of Q2.

[0067] The current of the circuit can also be controlled through the constant current source unit circuit 20 and the current mirror unit circuit 10, so that the circuit has low power consumption and is controllable.

[0068] When there is a resistance connection between Short_H and B+, the sensitivity of interface recognition can be changed by adjusting the resistance values of R2, R4, R10 and R11, and the misrecognition of the circuit can be effectively avoided.

[0069] The temperature compensation unit circuit 30 reduces the influence of temperature on the circuit and improves the reliability of the circuit operation.

[0070] In summary, compared with the interface recognition circuit of the prior art, the interface recognition circuit of the embodiment has smaller working power consumption and almost no power consumption when the circuit is turned off; the constant current source and the current mirror structure are introduced, so that the circuit has a wide range of working voltage of 10-150V; the temperature compensation module is introduced, so that the influence of temperature on the transistor can be well inhibited; and the threshold resistance and the working power consumption can be adjusted according to actual use requirements.

[0071] Embodiment Two

[0072] As another optional implementation, the current mirror can be expanded to multiple outputs, so that the use environment of multi-pin recognition can be met, and multiple constant current sources do not need to be used, thereby effectively reducing the device and working power consumption.

[0073] Specifically, as shown in Figure 4 , the current mirror unit circuit 10 of the interface recognition circuit includes a first branch and a plurality of parallel second branches. Figure 4

[0074] The current mirror unit circuit 10 of the interface recognition circuit includes a first branch and a plurality of parallel second branches.

[0075] The current mirror unit circuit 10 includes a first branch, and the first branch includes a resistor R4 and a switch tube Q5. The first end of the resistor R4 is the first input end of the current mirror unit circuit 10, the second end of the resistor R4 is electrically connected to the positive connection end of the switch tube Q5, the negative connection end of the switch tube Q5 is the first output end of the current mirror unit circuit 10, and the negative connection end and the control end of the switch tube Q5 are electrically connected.

[0076] The current mirror unit circuit 10 is provided with a plurality of second branches, and each second branch includes a mirror resistor and a mirror switch tube. The first end of the mirror resistor is the second input end of the current mirror unit circuit 10, the second end of the mirror resistor is electrically connected to the positive connection end of the mirror switch tube, the control end of the mirror switch tube is electrically connected to the control end of the switch tube Q5, and the negative connection end of the mirror switch tube is a second output end of the current mirror unit circuit 10.

[0077] Further, the control end of the mirror switch tube and the control end of the switch tube Q5 are further electrically connected to a current limiting resistor.

[0078] ​A diode D1 is electrically connected between the first terminal of resistor R4 and the positive terminal of the battery; a mirror diode is also electrically connected between the external interface of the battery and the first terminal of the mirror resistor.

[0079] In this configuration, the anode of diode D1 is used to electrically connect to the positive terminal of the battery, while the anode of the mirror diode is used to electrically connect to the external interface of the battery.

[0080] in, Figure 4 Diodes D2, D2-1, and D2-2 are the mirror diodes for each of the second branches. Figure 4 Resistors R2, R2-1, and R2-2 in the diagram are the mirror resistors of each of the second branches. Figure 4 In the circuit, switch Q3, switch Q3-1, and switch Q3-2 are mirror switches for each of the second branches.

[0081] Figure 4 The resistors R1, R1-1, and R1-2 are the current-limiting resistors for each of the second branches.

[0082] Furthermore, a temperature compensation unit circuit 30 is electrically connected between the second output terminal of the current mirror unit circuit 10 and the voltage input terminal of the conversion unit circuit 40.

[0083] The temperature compensation unit circuit 30 includes a temperature compensation diode, a first temperature compensation resistor, and a second temperature compensation resistor. The positive terminal of the temperature compensation diode is electrically connected to the first end of the voltage divider resistor and the first end of the first temperature compensation resistor, respectively. The negative terminal of the temperature compensation diode is electrically connected to the first end of the second temperature compensation resistor. The second end of the second temperature compensation resistor is grounded. The second end of the first temperature compensation resistor is electrically connected to the voltage input terminal of the conversion unit circuit 40.

[0084] Figure 4 In the diagram, diodes D3, D3-1, and D3-2 are temperature compensation diodes for each parallel branch, resistors R9, R9-1, and R9-2 are the first temperature compensation resistors for each parallel branch, resistors R12, R12-1, and R12-2 are the second temperature compensation resistors for each parallel branch, and resistors R11, R11-1, and R11-2 are the voltage divider resistors for each parallel branch.

[0085] Furthermore, the conversion unit circuit 40 includes a plurality of level conversion branches that are electrically connected to each of the second branches;

[0086] The level conversion branch includes a conversion switch tube and a conversion resistor; a control end of the conversion switch tube is a voltage input end of the conversion unit circuit 40, a first end of the conversion resistor is electrically connected to a reference power supply VCC inside the battery management system, a second end of the conversion resistor is electrically connected to a positive connection end of the conversion switch tube, and a negative connection end of the conversion switch tube is grounded.

[0087] The second end of the conversion resistor is a conversion level output end of the conversion unit circuit 40.

[0088] Figure 4 The resistors R6, R6-1 and R6-2 are conversion resistors of the parallel branches, respectively, and the switch tubes Q4, D4-1 and D4-2 are conversion switch tubes of the parallel branches, respectively.

[0089] Specifically, the first output end of the current mirror unit circuit 10 is further electrically connected to a first end of a resistor R3, a second end of the resistor R3 is electrically connected to a positive connection end of the constant current source unit circuit 20, and the second output end of the current mirror unit circuit 10 is further electrically connected to a first end of a protection resistor, a second end of the protection resistor is electrically connected to a first end of a voltage dividing resistor.

[0090] Figure 4 The resistors R8, R8-1 and R8-2 are protection resistors of the parallel branches, respectively.

[0091] Specifically, the constant current source unit circuit 20 includes a resistor R7, a switch tube Q2 and a resistor R10.

[0092] A first end of the resistor R7 is electrically connected to the reference power supply VCC inside the battery management system, a second end of the resistor R7 is electrically connected to a control end of the switch tube Q2, a positive connection end of the switch tube Q2 is electrically connected to a second end of the resistor R3, a negative connection end of the switch tube Q2 is electrically connected to a first end of the resistor R10, and a second end of the resistor R10 is grounded.

[0093] This embodiment is an extended circuit structure based on the embodiment one, the current mirror is extended to multi-output, which can meet the use environment of multi-pin identification, and multiple constant current sources are not needed. The device and working power consumption are effectively reduced.

[0094] Embodiment three

[0095] The embodiment provides a battery including a battery management system, the battery management system is electrically connected to an interface identification circuit, and the interface identification circuit adopts the interface identification circuit based on the current mirror in the embodiment one or the embodiment two.

[0096] Based on the detailed description of the interface identification circuit based on the current mirror in the embodiment one and the embodiment two, the description is not repeated in this embodiment.

[0097] In particular, the battery is a lithium battery pack.

[0098] The above-described and above-embodied examples are merely used to illustrate the technical solutions of the present application, rather than limit the same; although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can still be modified, or some technical features thereof can be replaced equivalently; and such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A current mirror based interface identification circuit, characterized by, The constant current source unit circuit (20) is electrically connected with the first output end of the current mirror unit circuit (10) at the positive terminal, and the negative terminal is grounded. The first input end of the current mirror unit circuit (10) is electrically connected with the positive pole of the battery, the second input end is electrically connected with the external interface of the battery to be identified, the second output end is electrically connected with the first end of the voltage dividing resistor and the voltage input end of the conversion unit circuit (40) respectively, the second end of the voltage dividing resistor is grounded, and the conversion level output end of the conversion unit circuit (40) is electrically connected with the MCU of the battery management system. The first output end of the current mirror unit circuit (10) is used for outputting constant current I1, the current outputted by the second output end of the current mirror unit circuit (10) is I2, and I1 / I2 is linearly related to the resistance value of the connecting resistor of the external interface of the battery.

2. The current mirror based interface identification circuit of claim 1, wherein, The current mirror unit circuit (10) comprises a first branch, the first branch comprises a resistor R4 and a switch tube Q5, the first end of the resistor R4 is the first input end of the current mirror unit circuit (10), the second end of the resistor R4 is electrically connected with the positive terminal of the switch tube Q5, the negative terminal of the switch tube Q5 is the first output end of the current mirror unit circuit (10), and the negative terminal and the control end of the switch tube Q5 are electrically connected. The current mirror unit circuit (10) is provided with at least one second branch, the second branch comprises a mirror resistor and a mirror switch tube, the first end of the mirror resistor is the second input end of the current mirror unit circuit (10), the second end of the mirror resistor is electrically connected with the positive terminal of the mirror switch tube, the control end of the mirror switch tube is electrically connected with the control end of the switch tube Q5, and the negative terminal of the mirror switch tube is a second output end of the current mirror unit circuit (10). The resistance value of the resistor R4 is i, the resistance value of the mirror resistor is j, the resistance value of the connecting resistor is k, and the relationship between the current I2 and the resistance value of the connecting resistor of the external interface of the battery is expressed as: I2=I1*i / (j+k).

3. The current mirror based interface identification circuit of claim 2, wherein, The control end of the mirror switch tube and the control end of the switch tube Q5 are further electrically connected with a current limiting resistor; The first end of the resistor R4 and the positive pole of the battery are further electrically connected with a diode D1, and the external interface of the battery and the first end of the mirror resistor are further electrically connected with a mirror diode. The positive pole of the diode D1 is used for electrically connecting the positive pole of the battery, and the positive pole of the mirror diode is used for electrically connecting the external interface of the battery.

4. The current mirror based interface identification circuit of claim 2, wherein, The second output end of the current mirror unit circuit (10) and the voltage input end of the conversion unit circuit (40) are further electrically connected with a temperature compensation unit circuit (30). The temperature compensation unit circuit (30) comprises a temperature compensation diode, a first temperature compensation resistor and a second temperature compensation resistor, the positive pole of the temperature compensation diode is electrically connected with the first end of the voltage dividing resistor and the first end of the first temperature compensation resistor respectively, the negative pole of the temperature compensation diode is electrically connected with the first end of the second temperature compensation resistor, the second end of the second temperature compensation resistor is grounded, and the second end of the first temperature compensation resistor is electrically connected with the voltage input end of the conversion unit circuit (40).

5. The current mirror based interface identification circuit of claim 4, wherein, The conversion unit circuit (40) comprises several level conversion branches respectively electrically connected with the second branches; The level conversion branch comprises a conversion switch tube and a conversion resistor; a control end of the conversion switch tube is a voltage input end of the conversion unit circuit (40), a first end of the conversion resistor is electrically connected with a reference power supply VCC inside the battery management system, a second end of the conversion resistor is electrically connected with a positive connection end of the conversion switch tube, and a negative connection end of the conversion switch tube is grounded. The second end of the conversion resistor is a conversion level output end of the conversion unit circuit (40).

6. The current mirror based interface identification circuit of claim 5, wherein, The first output end of the current mirror unit circuit (10) is further electrically connected with a first end of a resistance R3, a second end of the resistance R3 is electrically connected with a positive connection end of the constant current source unit circuit (20), the second output end of the current mirror unit circuit (10) is further electrically connected with a first end of a protection resistance, and a second end of the protection resistance is electrically connected with a first end of a voltage dividing resistance.

7. The current mirror based interface identification circuit of claim 6, wherein, The constant current source unit circuit (20) comprises a resistance R7, a switch tube Q2 and a resistance R10. A first end of the resistance R7 is electrically connected with the reference power supply VCC inside the battery management system, a second end of the resistance R7 is electrically connected with a control end of the switch tube Q2, a positive connection end of the switch tube Q2 is electrically connected with a second end of the resistance R3, a negative connection end of the switch tube Q2 is electrically connected with a first end of the resistance R10, and a second end of the resistance R10 is grounded.

8. The current mirror based interface identification circuit of claim 7, wherein, The switch tube Q5 and the mirror switch tube are PNP triodes of the same type, and the switch tube Q2 and the conversion switch tube are NPN triodes.

9. A battery comprising a battery management system, the battery management system being electrically connected with an interface identification circuit, characterized in that, The interface identification circuit adopts the current mirror-based interface identification circuit according to any one of claims 1-8.

10. The battery of claim 9, wherein, The battery is a lithium battery pack.

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