Current detection circuit system, current detection method, and electric vehicle

Abstract

The present application provides a current detection circuit system and a current detection method, and an electric vehicle, which relate to the field of small current detection technology. The current detection circuit system includes: a detection circuit, which is used to detect the input current, and output a high level or a low level according to whether the input current is greater than a first threshold; a main control circuit; a main discharge control circuit is used to receive the high level output by the detection circuit and conduct when the input current is greater than or equal to the first threshold; a pre-discharge control circuit is used to receive the high level output by the detection circuit and conduct when the input current is less than the first threshold; a current sampling circuit is connected to the pre-discharge control circuit, and is used to determine the value of the input current when the input current is less than the first threshold. The circuit system can solve the problem of sampling accuracy of the battery under small current conditions, reduce the influence of the current prediction error on the judgment of the battery's state of charge, and improve the accuracy of estimating the battery's state of charge.

Description

Technical Field

[0001] The present application relates to the technical field of small current detection, and in particular to a current detection circuit system, a current detection method, and an electric vehicle. Background Art

[0002] In the process of calculating the battery state of charge of two-wheeled electric vehicles and power-assisted bicycles, the accuracy of the state of charge calculation is highly dependent on the accuracy of current sampling. In the two-wheeled electric vehicle market, after the vehicle is locked, the entire system is in a low-power operation state, with an operating power consumption of <100mA. Usually, the current sampled at this time is affected by the analog front-end accuracy and the sampling resistor value, which will lead to inaccurate current sampling.

[0003] At present, most methods on the market perform current sampling based on the analog front end after analog current calibration. In computing scenarios with high requirements for current accuracy, it will be affected by the accuracy of the analog front end, the resistance of the sampling resistor, the temperature conditions of the sampling environment, and these disadvantages will be more prominent when collecting small currents. In addition, when the battery is operating under small current conditions, there is a situation where currents less than 50mA are not counted, and the error introduced will be large. The above phenomena will affect the judgment and calculation of the battery charge state. Summary of the invention

[0004] In order to solve at least one of the above problems, the present application proposes a current detection circuit system, a current detection method, and an electric vehicle.

[0005] According to the first aspect of the present application, at least one embodiment of the present application provides a current detection circuit system, including: a detection circuit, used to detect an input current, and output a high level or a low level according to whether the input current is greater than a first threshold value; a main control circuit, connected to the detection circuit; a main discharge control circuit, connected to the detection circuit and the main control circuit respectively, for receiving the high level output by the detection circuit and turning on when the input current is greater than or equal to the first threshold value; a pre-discharge control circuit, connected to the detection circuit and the main control circuit respectively, for receiving the high level output by the detection circuit and turning on when the input current is less than the first threshold value; a current sampling circuit, connected to the pre-discharge control circuit, for determining the value of the input current when the input current is less than the first threshold value.

[0006] For example, in some embodiments of the present application, the main control circuit includes: a first field effect transistor, whose source is connected to the input current terminal; a first resistor, one end of which is connected to the gate of the first field effect transistor and the other end is grounded; a second resistor, one end of which is connected to the first signal output terminal of the detection circuit and the other end is connected to the gate of the first field effect transistor.

[0007] For example, in some embodiments of the present application, the main discharge control circuit includes: a second field effect transistor, a drain connected to the drain of the first field effect transistor, and a source connected to the output current terminal; a third resistor, one end of which is connected to the gate of the second field effect transistor and the other end is grounded; a fourth resistor, one end of which is connected to the second signal output terminal of the detection circuit and the other end is connected to the gate of the second field effect transistor.

[0008] For example, in some embodiments of the present application, the pre-discharge control circuit includes: a third field effect transistor, whose source is connected to the drain of the first field effect transistor; a fifth resistor, one end of which is connected to the output current end; a sixth resistor, one end of which is connected to the drain of the third field effect transistor, and the other end of which is connected to the other end of the fifth resistor; a seventh resistor, which is connected in parallel to the gate and source of the third field effect transistor; and an eighth resistor, one end of which is connected to the gate of the third field effect transistor, and the other end of which is connected to the third signal output end of the detection circuit.

[0009] For example, in some embodiments of the present application, the current sampling circuit includes: a ninth resistor, one end of which is connected to the other end of the fifth resistor; a tenth resistor, one end of which is connected to one end of the fifth resistor; an eleventh resistor, one end of which is connected to the other end of the ninth resistor, and the other end is grounded; a twelfth resistor, one end of which is connected to the other end of the tenth resistor, and the other end is grounded; a first chip, a first input end of which is connected to the other end of the ninth resistor, a second input end of which is connected to the other end of the tenth resistor, and a power supply end of which is connected to a power supply; a thirteenth resistor, one end of which is connected to the output end of the first chip; a collection module, connected to the other end of the thirteenth resistor, for determining the value of the input current; a first capacitor, one end of which is connected to the power supply, and the other end is grounded.

[0010] For example, in some embodiments of the present application, the detection circuit is configured as follows: when the input current is greater than or equal to the first threshold, the first signal output terminal and the second signal output terminal of the detection circuit output a high level, and the third signal output terminal outputs a low level; when the input current is less than the first threshold, the first signal output terminal and the third signal output terminal of the detection circuit output a high level, and the second signal output terminal outputs a low level.

[0011] For example, in some embodiments of the present application, the detection circuit is further configured to: detect whether the battery is in a charging state; when the battery is in a charging state, the first signal output terminal and the second signal output terminal of the detection circuit output a high level, and the third signal output terminal outputs a low level.

[0012] According to the second aspect of the present application, at least one embodiment of the present application provides a current detection method, which is performed by a detection circuit of a current detection circuit system as described in any one of the first aspects, and the current detection method includes: detecting whether the input current is greater than the first threshold value; when the input current is greater than or equal to the first threshold value, controlling the first signal output terminal and the second signal output terminal to output a high level, and the third signal output terminal to output a low level, so that the main control circuit and the main discharge control circuit are turned on, and the pre-discharge control circuit is turned off; when the input current is less than the first threshold value, controlling the first signal output terminal and the third signal output terminal to output a high level, and the second signal output terminal to output a low level, so that the main control circuit and the pre-discharge control circuit are turned on, and the main discharge control circuit is turned off, so that the current sampling circuit can determine the value of the input current.

[0013] For example, in some embodiments of the present application, it also includes: detecting whether the battery is in a charging state; when the battery is in a charging state, controlling the first signal output terminal and the second signal output terminal to output a high level, and the third signal output terminal to output a low level.

[0014] According to a third aspect of the present application, at least one embodiment of the present application provides an electric vehicle, comprising: a battery; and a current detection circuit system as described in any one of the third aspects, connected to the battery and used to detect the current of the battery.

[0015] Through the above-mentioned example embodiments, the present application provides a current detection circuit system and a current detection method, which solve the problem of battery sampling accuracy under low current conditions, reduce the influence of current prediction error on the battery state of charge judgment, and improve the accuracy of estimating the battery state of charge.

[0016] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By describing in detail exemplary embodiments thereof with reference to the accompanying drawings, the above and other objects, features and advantages of the present application will become more apparent. The accompanying drawings described below are only some embodiments of the present application, and are not intended to limit the present application.

[0018] Figure 1 A schematic diagram showing a current sensing circuit system of an exemplary embodiment;

[0019] Figure 2 A circuit diagram showing a current detection circuit system of an exemplary embodiment;

[0020] Figure 3A flow chart showing a current detection method according to an exemplary embodiment is shown. DETAILED DESCRIPTION

[0021] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0022] The described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other modes, components, materials, devices, etc. may be adopted. In these cases, known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0023] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0024] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0025] Those skilled in the art will appreciate that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present application, and therefore cannot be used to limit the scope of protection of the present application.

[0026] Figure 1 A schematic diagram showing current sensing circuitry of an exemplary embodiment is shown.

[0027] like Figure 1 As shown, the current detection circuit system includes: a detection circuit 101 , a main control circuit 102 , a main discharge control circuit 103 , a pre-discharge control circuit 104 and a current sampling circuit 105 .

[0028] Among them, the detection circuit 101 is used to detect the input current, and output a high level or a low level according to whether the input current is greater than a first threshold value. The main control circuit 102 is connected to the detection circuit 101, and is used to receive the level signal output by the detection circuit. The main discharge control circuit 103 is connected to the detection circuit 101 and the main control circuit 102 respectively, and is used to receive the high level signal output by the detection circuit 101 and conduct when the input current is greater than or equal to the first threshold value. The pre-discharge control circuit 104 is connected to the detection circuit 101 and the main control circuit 102 respectively, and is used to receive the high level signal output by the detection circuit 101 and conduct when the input current is less than the first threshold value. The current sampling circuit 105 is connected to the pre-discharge control circuit 104, and is used to determine the value of the input current when the input current is less than the first threshold value.

[0029] According to some embodiments, the first threshold value can be set by itself, such as 50 mA, but the present application is not limited thereto.

[0030] Figure 2 A circuit diagram showing a current detection circuit system of an exemplary embodiment is shown.

[0031] like Figure 2 As shown, the main control circuit 102 includes: a first field effect transistor Q1, a first resistor R1 and a second resistor R2.

[0032] The source of the first field effect transistor Q1 is connected to the input current terminal B+. One end of the first resistor R1 is connected to the gate of the first field effect transistor Q1, and the other end is grounded. One end of the second resistor R2 is connected to the first signal output terminal CHG of the detection circuit 101, and the other end is connected to the gate of the first field effect transistor Q1.

[0033] The main discharge control circuit 103 includes: a second field effect transistor Q2, a third resistor R3 and a fourth resistor R4.

[0034] The drain of the second field effect transistor Q2 is connected to the drain of the first field effect transistor Q1, and the source is connected to the output current terminal P+. One end of the third resistor R3 is connected to the gate of the second field effect transistor Q2, and the other end is grounded. One end of the fourth resistor R4 is connected to the second signal output terminal DSG of the detection circuit 101, and the other end is connected to the gate of the second field effect transistor Q2.

[0035] The pre-discharge control circuit 104 includes: a third field effect transistor Q3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8.

[0036] Among them, the source of the third field effect transistor Q3 is connected to the drain of the first field effect transistor Q1. One end of the fifth resistor R5 is connected to the output current terminal P+. One end of the sixth resistor R6 is connected to the drain of the third field effect transistor Q3, and the other end is connected to the other end of the fifth resistor R5. The seventh resistor R7 is connected in parallel with the gate and source of the third field effect transistor Q3. One end of the eighth resistor R8 is connected to the gate of the third field effect transistor Q3, and the other end is connected to the third signal output terminal PDSG of the detection circuit 101.

[0037] According to some embodiments, the sixth resistor R6 is used to limit current, and the fifth resistor R5 is a sampling resistor.

[0038] The current sampling circuit 105 includes: a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a first chip U1, a sampling module 1051 and a first capacitor C1.

[0039] Among them, one end of the ninth resistor R9 is connected to the other end of the fifth resistor R5. One end of the tenth resistor R10 is connected to one end of the fifth resistor R5. One end of the eleventh resistor R11 is connected to the other end of the ninth resistor R9, and the other end is grounded. One end of the twelfth resistor R12 is connected to the other end of the tenth resistor R10, and the other end is grounded. The first input terminal VIN+ of the first chip U1 is connected to the other end of the ninth resistor R9, the second input terminal VIN- is connected to the other end of the tenth resistor R10, the ground terminal GND is grounded, and the power supply terminal V+ is connected to the power supply VCC. One end of the thirteenth resistor R13 is connected to the output terminal OUT of the first chip U1. The acquisition module 1051 is connected to the other end of the thirteenth resistor R13 for determining the value of the input current. One end of the first capacitor C1 is connected to the power supply, and the other end is grounded.

[0040] According to some embodiments, the ninth resistor R9 , the tenth resistor R10 , the eleventh resistor R11 , and the twelfth resistor R12 function to adjust the multiple of U1 , and the thirteenth resistor R13 functions to limit current.

[0041] The first field effect transistor Q1 , the second field effect transistor Q2 and the third field effect transistor Q3 are NMOS transistors.

[0042] According to an exemplary embodiment, the detection circuit 101 is configured as follows: when the input current is greater than or equal to the first threshold, the first signal output terminal CHG and the second signal output terminal DSG of the detection circuit 101 output a high level, and the third signal output terminal PDSG outputs a low level. The first signal output terminal CHG outputs a high level, and the voltage is divided by the second resistor R2 and the first resistor R1, so that the first field effect transistor Q1 is turned on. The second signal output terminal DSG outputs a high level, and the voltage is divided by the fourth resistor R4 and the third resistor R3, so that the second field effect transistor Q2 is turned on. The third signal output terminal PDSG outputs a low level, the third field effect transistor Q3 is turned off, and a large current flows from the input current terminal B+ through the first field effect transistor Q1 and the second field effect transistor Q2 to the output current terminal P+.

[0043] When the input current is less than the first threshold, the first signal output terminal CHG and the third signal output terminal PDSG of the detection circuit 101 output a high level, and the second signal output terminal DSG outputs a low level. The first signal output terminal CHG outputs a high level, and the voltage is divided by the second resistor R2 and the first resistor R1, so that the first field effect tube Q1 is turned on. The third signal output terminal PDSG outputs a high level, and the voltage is divided by the seventh resistor R7 and the eighth resistor R8, so that the third field effect tube Q3 is turned on. The second signal output terminal DSG outputs a low level. Since the third resistor R3 is grounded, the second field effect tube Q2 is turned off, and a small current passes through the input current terminal B+ through the first field effect tube Q1 and the third field effect tube Q3, and then to the sixth resistor R6 and the fifth resistor R5, and finally flows to the output current terminal P+. The fifth resistor R5 is a sampling resistor. The first chip U1 collects the current at both ends of the fifth resistor R5 through the first input terminal VIN+ and the second input terminal VIN-, and outputs the sampled current to the acquisition module 1051 through the output terminal OUT of the first chip U1 to detect the current, thereby realizing high-precision small and medium current sampling.

[0044] The present application also proposes a current detection method, which is performed by the detection circuit of the current detection circuit system as described above, including steps S301-S304. Figure 3 As shown:

[0045] In step S301, it is detected whether the battery is in a charging state.

[0046] The detection circuit detects whether the battery is in a charging state. If so, the process goes to step S303; if not, the process goes to step S302.

[0047] In step S302, it is detected whether the input current is greater than a first threshold.

[0048] The detection circuit detects whether the input current of the current input terminal is greater than a first threshold value, if it is greater than or equal to the first threshold value, then proceeds to step S303; if it is less than the first threshold value, then proceeds to step S304.

[0049] In step S303, the first signal output terminal and the second signal output terminal are controlled to output a high level, and the third signal output terminal is controlled to output a low level.

[0050] When the input current is greater than or equal to the first threshold value or the battery is in a charging state, the detection circuit controls the first signal output terminal and the second signal output terminal to output a high level, and the third signal output terminal to output a low level, so that the main control circuit and the main discharge control circuit are turned on, and the pre-discharge control circuit is turned off, and a large current flows from the input current terminal B+ through the first field effect transistor Q1 of the main control circuit and the second field effect transistor Q2 of the main discharge control circuit to the output current terminal P+

[0051] In step S304, the first signal output terminal and the third signal output terminal are controlled to output a high level, and the second signal output terminal is controlled to output a low level.

[0052] When the input current is less than the first threshold value, the detection circuit controls the first signal output terminal and the third signal output terminal to output a high level, and the second signal output terminal to output a low level, so that the main control circuit and the pre-discharge control circuit are turned on, and the main discharge control circuit is turned off. A small current flows through the input current terminal B+ through the first field effect transistor Q1 of the main control circuit and the third field effect transistor Q3 of the pre-discharge control circuit to the output current terminal P+, so that the current sampling circuit can collect the current across the fifth resistor R5 to determine the value of the input current, thereby achieving high-precision sampling of small and medium currents.

[0053] The present application provides a current detection circuit system and a current detection method to solve the problem of battery sampling accuracy under low current conditions, reduce the influence of current prediction error on battery charge state judgment, and improve the accuracy of estimating the battery charge state.

[0054] The present application also provides an electric vehicle, comprising a battery and a current detection circuit system as described above. The current detection circuit system is connected to the battery and is used to detect the low current of the battery. The specific working principle is as described above, thereby realizing the calculation of the battery's state of charge.

[0055] According to some embodiments, the electric vehicles referred to in this application include two-wheeled electric vehicles and resistance bicycles, etc. This application only takes this as an example, but is not limited thereto. And the current detection circuit system of this application can also be used in other occasions where battery current needs to be detected.

[0056] It should be clearly understood that the present application describes how to form and use specific examples, but the present application is not limited to any details of these examples. On the contrary, based on the teaching of the content disclosed in the present application, these principles can be applied to many other embodiments.

[0057] In addition, it should be noted that the above figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, and are not intended to be limiting. It is easy to understand that the processes shown in the above figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0058] The exemplary embodiments of the present application are specifically shown and described above. It should be understood that the present application is not limited to the detailed structures, configurations or implementations described herein; on the contrary, the present application is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A current detection circuit system, characterized in that: include: A detection circuit, used for detecting an input current and outputting a high level or a low level according to whether the input current is greater than a first threshold; A main control circuit connected to the detection circuit; a main discharge control circuit, connected to the detection circuit and the main control circuit respectively, and configured to receive a high level output by the detection circuit and conduct when the input current is greater than or equal to the first threshold; a pre-discharge control circuit, connected to the detection circuit and the main control circuit respectively, and configured to receive a high level output by the detection circuit and conduct when the input current is less than the first threshold; A current sampling circuit is connected to the pre-discharge control circuit and is used to determine the value of the input current when the input current is less than the first threshold value.

2. The current detection circuit system according to claim 1, characterized in that: The main control circuit comprises: A first field effect transistor, a source electrode of which is connected to an input current terminal; A first resistor, one end of which is connected to the gate of the first field effect transistor and the other end of which is grounded; A second resistor has one end connected to the first signal output end of the detection circuit and the other end connected to the gate of the first field effect transistor.

3. The current detection circuit system according to claim 2, characterized in that: The main discharge control circuit comprises: A second field effect transistor, a drain electrode connected to the drain electrode of the first field effect transistor, and a source electrode connected to the output current terminal; a third resistor, one end of which is connected to the gate of the second field effect transistor and the other end of which is grounded; A fourth resistor has one end connected to the second signal output end of the detection circuit, and the other end connected to the gate of the second field effect transistor.

4. The current detection circuit system according to claim 2, characterized in that: The pre-discharge control circuit comprises: a third field effect transistor, a source electrode of which is connected to a drain electrode of the first field effect transistor; a fifth resistor, one end of which is connected to the output current end; a sixth resistor, one end of which is connected to the drain of the third field effect transistor, and the other end of which is connected to the other end of the fifth resistor; a seventh resistor connected in parallel with the gate and source of the third field effect transistor; An eighth resistor has one end connected to the gate of the third field effect transistor, and the other end connected to the third signal output terminal of the detection circuit.

5. The current detection circuit system according to claim 4, characterized in that: The current sampling circuit comprises: a ninth resistor, one end of which is connected to the other end of the fifth resistor; a tenth resistor, one end of which is connected to one end of the fifth resistor; an eleventh resistor, one end of which is connected to the other end of the ninth resistor, and the other end of which is grounded; a twelfth resistor, one end of which is connected to the other end of the tenth resistor, and the other end of which is grounded; A first chip, wherein a first input terminal is connected to the other end of the ninth resistor, a second input terminal is connected to the other end of the tenth resistor, and a power supply terminal is connected to a power supply; a thirteenth resistor, one end of which is connected to the output end of the first chip; A collection module, connected to the other end of the thirteenth resistor, for determining the value of the input current; The first capacitor has one end connected to the power supply and the other end grounded.

6. The current detection circuit system according to claim 1, characterized in that: The detection circuit is configured as follows: When the input current is greater than or equal to the first threshold, the first signal output terminal and the second signal output terminal of the detection circuit output a high level, and the third signal output terminal outputs a low level; When the input current is less than the first threshold, the first signal output terminal and the third signal output terminal of the detection circuit output a high level, and the second signal output terminal outputs a low level.

7. The current detection circuit system according to claim 6, characterized in that: The detection circuit is further configured as: Check whether the battery is in charging state; When the battery is in a charging state, the first signal output terminal and the second signal output terminal of the detection circuit output a high level, and the third signal output terminal outputs a low level.

8. A current detection method, characterized in that: The current detection method is performed by the detection circuit of the current detection circuit system according to any one of claims 1 to 7, and comprises: Detecting whether the input current is greater than the first threshold; When the input current is greater than or equal to the first threshold, the first signal output terminal and the second signal output terminal are controlled to output a high level, and the third signal output terminal is controlled to output a low level, so that the main control circuit and the main discharge control circuit are turned on, and the pre-discharge control circuit is turned off; When the input current is less than the first threshold value, the first signal output terminal and the third signal output terminal are controlled to output a high level, and the second signal output terminal is controlled to output a low level, so that the main control circuit and the pre-discharge control circuit are turned on, and the main discharge control circuit is turned off, so that the current sampling circuit can determine the value of the input current.

9. The current detection method according to claim 8, characterized in that: Also includes: Check whether the battery is in charging state; When the battery is in a charging state, the first signal output terminal and the second signal output terminal are controlled to output a high level, and the third signal output terminal is controlled to output a low level.

10. An electric vehicle, characterized in that: include: Battery; The current detection circuit system according to any one of claims 1 to 7, connected to the battery, for detecting the current of the battery.

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