Bias current circuit, fluxgate current sensor and control method

Abstract

The invention relates to a bias current circuit, a fluxgate current sensor and a control method. The bias current circuit comprises a bias voltage module, a bias current module and a controller, the input end of the bias voltage module is connected with power supply voltage, the output end of the bias voltage module is connected with the input end of the bias current module, and the controller is connected with the bias voltage module; the controller is used for controlling the bias voltage module to output preset bias voltage; and the bias current module is used for outputting target bias current corresponding to the preset bias voltage under the action of the preset bias voltage. According to the bias current circuit, the bias current can be adjusted by adjusting the bias voltage, so that bias currents with different magnitudes can be provided according to different scene requirements, and a power electronic device applying the bias current circuit can be flexibly switched in different working states; therefore, different scene requirements and scene applications are met; the adjustability of the bias current is improved, and diversified actual requirements are met.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a bias current circuit, a fluxgate current sensor, and a control method. Background Art

[0002] As a commonly used detection device, the current sensor can detect the current information to be measured in the circuit, which is conducive to current safety protection. At present, the current sensor with bias current has a bias circuit that can provide a certain value of bias current for the current sensor, thereby changing the output current of the current sensor, so that the current sensor or the power electronic device containing the current sensor can work in certain specific working conditions to meet the needs of specific scenarios.

[0003] However, the bias current value of the conventional current sensor with bias current is fixed and cannot adapt to diverse practical needs. Summary of the invention

[0004] Based on this, it is necessary to provide a bias current circuit, a fluxgate current sensor and a control method that can realize adjustable bias current to adapt to the requirements of different scenarios in order to address the above technical problems.

[0005] In a first aspect, the present application provides a bias current circuit, comprising: a bias voltage module, a bias current module and a controller, wherein an input end of the bias voltage module is connected to a power supply voltage, an output end of the bias voltage module is connected to an input end of the bias current module, and the controller is connected to the bias voltage module;

[0006] A controller, used for controlling the bias voltage module to output a preset bias voltage;

[0007] The bias current module is used to output a target bias current corresponding to the preset bias voltage under the action of the preset bias voltage.

[0008] In one embodiment, the bias voltage module includes: a first voltage stabilizing submodule and a second voltage stabilizing submodule, the input end of the first voltage stabilizing submodule is connected to the power supply voltage, and the output end of the first voltage stabilizing submodule is connected to the first input end of the bias current module; the input end of the second voltage stabilizing submodule is connected to the power supply voltage, and the output end of the second voltage stabilizing submodule is connected to the second input end of the bias current module;

[0009] The controller is used to control the first voltage stabilizing submodule to output a first preset voltage, and / or control the second voltage stabilizing submodule to output a second preset voltage, and the difference between the first preset voltage and the second preset voltage is a preset bias voltage.

[0010] In one embodiment, the bias current module includes: a first resistor, a first diode and a first transistor, one end of the first resistor is a first input end of the bias current module, the input end of the first diode is a second input end of the bias current module, and the collector of the first transistor is an output end of the bias current module;

[0011] The other end of the first resistor is respectively connected to the output end of the first diode, the base of the first transistor and the emitter of the first transistor; the output end of the first diode is connected to the base of the first transistor.

[0012] In one embodiment, the target bias current is the output current of the collector of the first transistor, the output current of the collector of the first transistor is the product of the input current of the base of the first transistor and the amplification factor of the first transistor, and the input current of the base of the first transistor is the ratio of the preset bias voltage to the resistance value of the first resistor.

[0013] In one embodiment, the first voltage stabilizing submodule includes a first voltage stabilizing chip, a second resistor, a third resistor, a fourth resistor and a first capacitor;

[0014] One end of the second resistor is connected to the power supply voltage, and the other end of the second resistor is respectively connected to the output end of the first voltage stabilizing chip, one end of the third resistor and one end of the first capacitor, and the other end of the second resistor is the output end of the first voltage stabilizing submodule;

[0015] The input end of the first voltage stabilizing chip is respectively connected to the other end of the third resistor and one end of the fourth resistor, and the other end of the third resistor is connected to one end of the fourth resistor;

[0016] The grounding end of the first voltage stabilizing chip, the other end of the fourth resistor and the other end of the first capacitor are all grounded.

[0017] In one embodiment, the controller is used to adjust the resistance value of the third resistor and / or the resistance value of the fourth resistor to control the output end of the first voltage stabilizing submodule to output the first preset voltage.

[0018] In one embodiment, the second voltage stabilizing submodule includes a second voltage stabilizing chip, a fifth resistor, a sixth resistor, a seventh resistor, and a second capacitor;

[0019] One end of the fifth resistor is connected to the supply voltage, the other end of the fifth resistor is respectively connected to the output end of the second voltage stabilizing chip, one end of the sixth resistor and one end of the second capacitor, and the other end of the fifth resistor is the output end of the second voltage stabilizing submodule;

[0020] The input end of the second voltage stabilizing chip is respectively connected to the other end of the sixth resistor and one end of the seventh resistor, and the other end of the sixth resistor is connected to one end of the seventh resistor;

[0021] The grounding end of the second voltage stabilizing chip, the other end of the sixth resistor and the other end of the second capacitor are all grounded.

[0022] In one embodiment, the controller is used to adjust the resistance value of the sixth resistor and / or the resistance value of the seventh resistor to control the output end of the second voltage stabilizing submodule to output the second preset voltage.

[0023] In a second aspect, the present application further provides a fluxgate current sensor, including a flux detection circuit, a zero-point debugging circuit, an output comparison and push-pull output circuit, and an anti-current backflow circuit, and further including: a bias current circuit as in the first aspect;

[0024] The magnetic flux detection circuit, the zero point debugging circuit and the output comparison and push-pull output circuit are connected in sequence, and the output comparison and push-pull output circuit and the bias current circuit are connected to the current backflow prevention circuit respectively;

[0025] The output current of the current backflow prevention circuit is the sum of the compensation current output by the output comparison and push-pull output circuit and the target bias current output by the bias current circuit.

[0026] In a third aspect, the present application further provides a control method, which is applied to the fluxgate current sensor in the second aspect, and the method comprises:

[0027] Get the target bias current;

[0028] According to the target bias current, the bias voltage module in the bias current circuit is adjusted to control the bias voltage module to output a preset bias voltage corresponding to the target bias current, so that the bias current module in the bias current circuit outputs the target bias current under the action of the preset bias voltage;

[0029] The current to be detected is input into the flux detection circuit, and the measurement current corresponding to the current to be detected output by the current backflow prevention circuit is obtained; the measurement current is the sum of the compensation current output by the output comparison and push-pull output circuit when the dynamic balance state is reached and the target bias current output by the bias current circuit.

[0030] The above-mentioned bias current circuit, fluxgate current sensor and control method, the bias current circuit includes a bias voltage module, a bias current module and a controller, wherein the input end of the bias voltage module is connected to the power supply voltage, the output end of the bias voltage module is connected to the input end of the bias current module, and the controller is connected to the bias voltage module; the controller is used to control the bias voltage module to output a preset bias voltage; the bias current module is used to output a target bias current corresponding to the preset bias voltage under the action of the preset bias voltage. That is to say, the bias current circuit proposed in the embodiment of the present application realizes adjustable bias current by adjusting the bias voltage in the bias current circuit, so that different sizes of bias current can be provided according to different scene requirements, so that the power electronic device using the bias current circuit can be flexibly switched in different working states, so as to meet different scene requirements and scene applications; the use of the bias current circuit can realize flexible adjustment of the bias current, improve the adjustability of the bias current, and adapt to diverse actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0032] FIG1 is a schematic diagram of a circuit structure of a bias current circuit in one embodiment;

[0033] FIG2 is a schematic diagram of a circuit structure of a bias current circuit in another embodiment;

[0034] FIG3 is a schematic diagram of a circuit structure of a bias current module in one embodiment;

[0035] FIG4 is a schematic diagram of the circuit structure of a first voltage stabilizing submodule in one embodiment;

[0036] FIG5 is a schematic diagram of the circuit structure of a second voltage stabilizing submodule in one embodiment;

[0037] FIG6 is a schematic diagram of a circuit structure of a fluxgate current sensor in one embodiment;

[0038] FIG7 is a schematic diagram of a circuit structure of a magnetic flux detection circuit in one embodiment;

[0039] FIG8 is a schematic diagram of the circuit structure of a zero-point debugging circuit in one embodiment;

[0040] FIG9 is a schematic diagram of the circuit structure of an output comparison and push-pull output circuit in one embodiment;

[0041] FIG10 is a schematic diagram of a circuit structure of a current backflow prevention circuit in one embodiment;

[0042] FIG. 11 is a flow chart of a control method in one embodiment.

[0043] Description of reference numerals:

[0044] 10: bias voltage module; 20: bias current module; 30: controller; 40: power supply voltage;

[0045] 11: first voltage stabilizing submodule; 12: second voltage stabilizing submodule;

[0046] 21: first resistor; 22: first diode; 23: first transistor; 111: first voltage stabilizing chip;

[0047] 112: second resistor; 113: third resistor; 114: fourth resistor; 115: first capacitor;

[0048] 121: second voltage stabilizing chip; 122: fifth resistor; 123: sixth resistor; 124: seventh resistor;

[0049] 125: second capacitor; 61: magnetic flux detection circuit; 62: zero point debugging circuit;

[0050] 63: Output comparison and push-pull output circuit; 64: Anti-current backflow circuit; 65: Bias current circuit;

[0051] 611: magnetic sensitive chip; 612: eighth resistor; 613: ninth resistor;

[0052] 621: tenth resistor; 622: eleventh resistor; 623: twelfth resistor; 624: thirteenth resistor;

[0053] 631: operational amplifier; 632: second capacitor; 633: third capacitor; 634: fourteenth resistor;

[0054] 635: second transistor; 636: third transistor; 637: inductor;

[0055] 641: a second diode; 642: a third diode; 643: a fifteenth resistor. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0058] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0059] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0060] As a commonly used detection device, the current sensor can detect the current information to be measured in the circuit, which is conducive to current safety protection. At present, the current sensor with bias current has a bias circuit that can provide a certain value of bias current for the current sensor, thereby changing the output current of the current sensor, so that the current sensor or the power electronic device containing the current sensor can work in certain specific working conditions to meet the needs of specific scenarios.

[0061] However, the bias current value of the conventional current sensor with bias current is fixed and cannot adapt to diverse practical needs.

[0062] Based on this, the embodiment of the present application proposes a stable and adjustable bias current circuit, a fluxgate current sensor implemented based on the bias current circuit, and a corresponding control method; wherein the fluxgate current sensor has a wide range of application scenarios because of its high sensitivity, small temperature drift, and high reliability, and can accurately reflect current changes. In the embodiment of the present application, the stable and adjustable bias current circuit is integrated into the fluxgate current sensor, and a fluxgate current sensor with a stable and adjustable bias current can be obtained.

[0063] FIG1 is a schematic diagram of the structure of the bias current circuit provided in an embodiment of the present application. As shown in FIG1 , the bias current circuit includes: a bias voltage module 10, a bias current module 20 and a controller 30, wherein the input end of the bias voltage module 10 is connected to the power supply voltage 40, the output end of the bias voltage module 10 is connected to the input end of the bias current module 20, and the controller 30 is connected to the bias voltage module 10.

[0064] The controller 30 is used to control the bias voltage module 10 to output a preset bias voltage; the bias current module 20 is used to output a target bias current corresponding to the preset bias voltage under the action of the preset bias voltage.

[0065] Exemplarily, the power supply voltage 40 can be provided by a voltage source VCC to provide a stable power supply voltage for the bias voltage module 10. When the bias voltage module 10 is powered, it can output a certain bias voltage based on the internal circuit parameters of the bias voltage module 10. The bias voltage can be used as the input voltage of the bias current module 20, so that the bias current module 20 can output a bias current corresponding to the bias voltage under the action of the bias voltage.

[0066] Based on this, when the bias current needs to be adjusted, that is, when the bias current circuit needs to output the desired target bias current, the internal circuit parameters of the bias voltage module 10 can be adjusted by the controller, so that the bias voltage module 10 outputs a preset bias voltage corresponding to the desired target bias current based on the adjusted internal circuit parameters, thereby enabling the bias current module 20 to output the target bias current corresponding to the preset bias voltage under the action of the preset bias voltage, that is, to achieve flexible adjustment of the bias current.

[0067] Exemplarily, the bias current module 20 may include at least a bias resistor, and the magnitude of the bias current output by the bias current module 20 may be a ratio between the bias voltage output by the bias voltage module 10 and the resistance value of the bias resistor. In some optional implementations, the bias resistor may be a resistor with a fixed resistance value or an adjustable resistor, and the bias current output by the bias current module 20 may be flexibly adjusted by adjusting the resistance value of the bias resistor.

[0068] Exemplarily, based on the bias current circuit proposed in the embodiment of the present application, the bias current can be adjusted by adjusting the bias resistor in the bias current module 20, or by adjusting the circuit parameters of the bias voltage module 10 to adjust the bias voltage to achieve adjustable bias current, or by adjusting the bias resistor and the bias voltage to achieve adjustable bias current; that is, the bias resistor and the bias voltage can be adjusted independently or simultaneously, and both achieve stable regulation of the bias current, and the embodiment of the present application does not make specific limitations on this.

[0069] Exemplarily, the controller 30 may be a programmable logic controller (PLC), referred to as a PLC controller, or a combinational logic controller (Combinatorial Logic Controller), or a hard wired controller (Hard Wired Controller), or a microprogram controller (Microprogram Controller), etc. The embodiment of the present application does not specifically limit the type of controller.

[0070] The above-mentioned bias current circuit includes a bias voltage module, a bias current module and a controller, wherein the input end of the bias voltage module is connected to the power supply voltage, the output end of the bias voltage module is connected to the input end of the bias current module, and the controller is connected to the bias voltage module; the controller is used to control the bias voltage module to output a preset bias voltage; the bias current module is used to output a target bias current corresponding to the preset bias voltage under the action of the preset bias voltage. In other words, the bias current circuit proposed in the embodiment of the present application realizes adjustable bias current by adjusting the bias voltage in the bias current circuit, so that bias currents of different sizes can be provided according to different scene requirements, so that the power electronic device using the bias current circuit can be flexibly switched in different working states, so as to meet different scene requirements and scene applications; the use of the bias current circuit can realize flexible adjustment of the bias current, improve the adjustability of the bias current, and adapt to diverse actual needs.

[0071] In an exemplary embodiment, as shown in FIG2 , a circuit structure diagram of a bias voltage module 10 is provided. The bias voltage module 10 includes: a first voltage stabilizing submodule 11 and a second voltage stabilizing submodule 12, wherein the input end of the first voltage stabilizing submodule 11 is connected to the power supply voltage 40, and the output end of the first voltage stabilizing submodule 11 is connected to the first input end of the bias current module 20; the input end of the second voltage stabilizing submodule 12 is connected to the power supply voltage 40, and the output end of the second voltage stabilizing submodule 12 is connected to the second input end of the bias current module 20. Based on this, the controller 30 is used to control the first voltage stabilizing submodule 11 to output a first preset voltage, and / or control the second voltage stabilizing submodule 12 to output a second preset voltage, and the difference between the first preset voltage and the second preset voltage is the preset bias voltage.

[0072] As shown in Figure 2, the controller 30 can be connected to the first voltage stabilizing submodule 11 or the second voltage stabilizing submodule 12. When adjusting the bias voltage, the output voltage of the first voltage stabilizing submodule 11 can be adjusted to keep the output voltage of the second voltage stabilizing submodule 12 unchanged; or, the output voltage of the second voltage stabilizing submodule 12 can be adjusted to keep the output voltage of the first voltage stabilizing submodule 11 unchanged; or, the output voltage of the first voltage stabilizing submodule 11 and the output voltage of the second voltage stabilizing submodule 12 can be adjusted at the same time to obtain an adjusted bias voltage.

[0073] Exemplarily, the first voltage stabilizing submodule 11 can be used to output a high voltage, and the second voltage stabilizing submodule 12 can be used to output a low voltage, that is, the first preset voltage is greater than the second preset voltage, and the difference between the first preset voltage and the second preset voltage is the preset bias voltage; of course, the first voltage stabilizing submodule 11 can also be used to output a low voltage, and the second voltage stabilizing submodule 12 can also be used to output a high voltage, that is, the first preset voltage is less than the second preset voltage, and the difference between the second preset voltage and the first preset voltage is the preset bias voltage; optionally, in other implementations, the first preset voltage can also be equal to the second preset voltage, at which time the difference between the first preset voltage and the second preset voltage is 0, that is, the preset bias voltage is 0, that is, the target bias current is 0, and when no bias current is required, the bias current output by the bias current circuit can also be controlled to be 0.

[0074] Exemplarily, taking the case where the first voltage stabilizing submodule 11 outputs a high voltage and the second voltage stabilizing submodule 12 outputs a low voltage, the first voltage stabilizing submodule 11 may be provided with a high voltage adjustment range, and the second voltage stabilizing submodule 12 may be provided with a low voltage adjustment range. When adjusting the bias voltage, the output voltage of the first voltage stabilizing submodule 11 may be adjusted preferentially, and the output voltage of the second voltage stabilizing submodule 12 may be kept unchanged, that is, the output voltage of the first voltage stabilizing submodule 11 may be adjusted within the high voltage adjustment range to achieve a preset bias voltage. When the output voltage of the first voltage stabilizing submodule 11 exceeds the high voltage adjustment range but fails to reach the preset bias voltage, the output voltage of the second voltage stabilizing submodule 12 may be adjusted, that is, the output voltage of the second voltage stabilizing submodule 12 may be adjusted within the low voltage adjustment range. At this time, the output voltage of the first voltage stabilizing submodule 11 may remain unchanged, or may be adaptively adjusted within the high voltage adjustment range to achieve the preset bias voltage.

[0075] It should be noted that the minimum voltage value of the high voltage regulation range can be equal to the maximum voltage value of the low voltage regulation range, so that the first preset voltage output by the first voltage stabilizing submodule 11 can be equal to the second preset voltage output by the second voltage stabilizing submodule 12, achieving 0 bias voltage, that is, achieving 0 bias current. Of course, the minimum voltage value of the high voltage regulation range can also be greater than or less than the maximum voltage value of the low voltage regulation range.

[0076] Exemplarily, when both the high voltage adjustment range and the low voltage adjustment range cannot meet the preset bias voltage, the target bias current can be further achieved by adjusting the bias resistor in the bias current module 20, that is, the bias voltage and the bias resistor are adjusted at the same time to achieve the target bias current; adopting this adjustment method, the adjustment range of the bias current can be increased, and more arbitrary adjustments to the bias current can be achieved. In addition, compared with adjusting the bias resistor first, since the bias voltage can be adjusted simultaneously in the high voltage adjustment range and the low voltage adjustment range, the adjustment range of the bias current can be increased, so that the bias current can be arbitrarily adjusted, thereby meeting more scene requirements.

[0077] In addition, the power supply voltages connected to the first voltage stabilizing submodule and the second voltage stabilizing submodule may be the same or different. That is, the first voltage stabilizing submodule and the second voltage stabilizing submodule may be powered by a power supply voltage of the same power supply level, or the first voltage stabilizing submodule and the second voltage stabilizing submodule may be powered by a power supply voltage of different power supply levels. The embodiment of the present application does not specifically limit this.

[0078] In this embodiment, by setting the first voltage stabilizing submodule and the second voltage stabilizing submodule in the bias voltage module, the first voltage stabilizing submodule and the second voltage stabilizing submodule output different voltages to generate a bias voltage; in addition, by performing voltage regulation within different voltage regulation ranges by the two voltage stabilizing submodules, the demand for bias current in more scenarios can be met, that is, the adjustable range of the bias current is increased, the universality of the bias current circuit is improved, and the applicable scenarios of the bias current circuit are enriched.

[0079] In an exemplary embodiment, as shown in FIG3 , a schematic diagram of a circuit structure of a bias current module is provided. The bias current module 20 may include: a first resistor 21, a first diode 22 and a first triode 23, one end of the first resistor 21 is a first input end of the bias current module 20, the input end of the first diode 22 is a second input end of the bias current module 20, and the collector of the first triode 23 is an output end of the bias current module 20; the other end of the first resistor 21 is respectively connected to the output end of the first diode 22, the base of the first triode 23 and the emitter of the first triode 23; the output end of the first diode 22 is connected to the base of the first triode 23.

[0080] Among them, the output end of the first voltage stabilizing submodule 11 is connected to the first input end of the bias current module 20, and one end of the first resistor 21 serves as the first input end of the bias current module 20, that is, the output end of the first voltage stabilizing submodule 11 is connected to one end of the first resistor 21; the output end of the second voltage stabilizing submodule 12 is connected to the second input end of the bias current module 20, and the input end of the first diode 22 (that is, the anode end of the first diode 22) serves as the second input end of the bias current module 20, that is, the output end of the second voltage stabilizing submodule 12 is connected to the input end (anode end) of the first diode 22.

[0081] In addition, the other end of the first resistor 21 is respectively connected to the output end of the first diode 22 (that is, the cathode end of the first diode 22), the base b of the first triode 23 and the emitter e of the first triode 23; the output end (cathode end) of the first diode 22 is respectively connected to the other end of the first resistor 21, the base b of the first triode 23 and the emitter e of the first triode 23; the base b of the first triode 23 is respectively connected to the other end of the first resistor 21, the output end (cathode end) of the first diode 22 and the emitter e of the first triode 23; the emitter e of the first triode 23 is respectively connected to the other end of the first resistor 21, the output end (cathode end) of the first diode 22 and the base b of the first triode 23.

[0082] Exemplarily, the collector c of the first transistor 23 can be used as the output end of the bias current module 20, that is, output bias current I0. Exemplarily, the first transistor 23 can be a PNP transistor.

[0083] Exemplarily, the first resistor 21 can be used to change the input current of the base b of the first transistor 23, that is, the base current I b is the ratio of the bias voltage to the resistance of the first resistor 21. Then, due to the current amplification effect of the first transistor 23, the output current I c is the base current I b The product of the gain β of the first transistor 23; the collector current I c That is, the bias current output by the bias current circuit 20, which can also be called the zero-point bias current.

[0084] That is, the target bias current output by the bias current circuit 20 is the output current I of the collector c of the first transistor 23. c , the output current I of the collector c of the first transistor 23 c is the input current I of the base b of the first transistor 23 b The product of the gain β of the first transistor 23, the input current I of the base b of the first transistor 23 bis the ratio of the preset bias voltage U to the resistance value of the first resistor 21 .

[0085] Exemplarily, the first diode 22 can be used to prevent current from flowing reversely into the second voltage stabilizing submodule 12 in the bias voltage module 10, thereby achieving current backflow protection.

[0086] Exemplarily, the first resistor 21 in the bias current circuit 20 can also serve as an adjustable bias resistor. By adjusting the resistance value of the first resistor 21, the bias current can also be adjusted. When the bias current cannot be satisfied by adjusting the bias voltage, the desired target bias current can be achieved by adjusting the resistance value of the first resistor 21 in combination with the bias voltage.

[0087] Exemplarily, in the bias current module 20, a plurality of transistors with different amplification factors may be provided, that is, the first transistor 23 may include a plurality of transistors with different amplification factors, and the base of each transistor is connected to the other end of the first resistor 21 and the output end (cathode end) of the first diode 22 through respective switching circuits, so that transistors with different amplification factors may be selected to amplify the bias current by controlling the switching circuits of different transistors. It should be noted that the base current of each transistor is the same, which is the ratio between the bias voltage and the resistance value of the first resistor, and bias currents of different sizes may be obtained through different amplification factors.

[0088] In this embodiment, a bias current module is composed of a first resistor, a first diode and a first transistor. A bias current is generated by the first resistor and a bias voltage, and the bias current is amplified. This enables arbitrary adjustment of the bias current and improves the application range of the bias current circuit.

[0089] In an exemplary embodiment, as shown in FIG4 , a circuit structure diagram of a first voltage stabilizing submodule is provided. The first voltage stabilizing submodule 11 may include a first voltage stabilizing chip 111, a second resistor 112, a third resistor 113, a fourth resistor 114 and a first capacitor 115; one end of the second resistor 112 is connected to the power supply voltage 40, and the other end of the second resistor 112 is respectively connected to the output end of the first voltage stabilizing chip 111, one end of the third resistor 113 and one end of the first capacitor 115, and the other end of the second resistor 112 is the output end of the first voltage stabilizing submodule 11; the input end of the first voltage stabilizing chip 111 is respectively connected to the other end of the third resistor 113 and one end of the fourth resistor 114, and the other end of the third resistor 113 is connected to one end of the fourth resistor 114; the ground end of the first voltage stabilizing chip 111, the other end of the fourth resistor 114 and the other end of the first capacitor 115 are all grounded.

[0090] Exemplarily, the power supply voltage 40 can be provided by a voltage source VCC, so that the first voltage stabilizing submodule 11 is powered by VCC. VCC can be connected to one end of the second resistor 112 in the first voltage stabilizing submodule 11, and the other end of the second resistor 112 is respectively connected to the output end of the first voltage stabilizing chip 111, one end of the third resistor 113, and one end of the first capacitor 115, and the other end of the second resistor 112 can be used as the output end of the first voltage stabilizing submodule 11 to output the first preset voltage, that is, the other end of the second resistor 112 is also connected to one end of the first resistor 21 in the bias current module 20; wherein, the second resistor 112 can be used to limit the current of the subsequent circuit.

[0091] In addition, the input end of the first voltage stabilizing chip 111 is respectively connected to the other end of the third resistor 113 and one end of the fourth resistor 114, that is, the input end of the first voltage stabilizing chip 111 is connected between the third resistor 113 and the fourth resistor 114; the output end of the first voltage stabilizing chip 111 is respectively connected to the other end of the second resistor 112, one end of the third resistor 113, one end of the first capacitor 115 and one end of the first resistor 21; the ground end of the first voltage stabilizing chip 111 is grounded.

[0092] Furthermore, one end of the third resistor 113 is respectively connected to the other end of the second resistor 112, the output end of the first voltage regulator chip 111, one end of the first capacitor 115 and one end of the first resistor 21 in the bias current module 20, the other end of the third resistor 113 is respectively connected to one end of the fourth resistor 114 and the input end of the first voltage regulator chip 111, and the other end of the fourth resistor 114 is grounded.

[0093] For the first resistor 21 in the bias current module 20, one end of the first resistor 21 is respectively connected to the other end of the second resistor 112, the output end of the first voltage regulator chip 111, one end of the third resistor 113 and one end of the first capacitor 115; the other end of the first resistor 21 is respectively connected to the output end (cathode end) of the first diode 22, the base of the first transistor 23 and the emitter of the first transistor 23.

[0094] In addition, one end of the first capacitor 115 is respectively connected to the other end of the second resistor 112, the output end of the first voltage regulator chip 111, one end of the third resistor 113 and one end of the first resistor 21; the other end of the first capacitor 115 is simultaneously connected to the ground end of the first voltage regulator chip 111 and the other end of the fourth resistor 114, and is grounded.

[0095] Exemplarily, based on the circuit structure of the first voltage stabilizing submodule 11 shown in FIG. 4 , without changing the bias voltage by adjusting the output voltage of the first voltage stabilizing submodule 11, the second resistor 112, the third resistor 113 and the fourth resistor 114 in the first voltage stabilizing submodule 11 can all be resistors of fixed resistance, so that the output end of the first voltage stabilizing submodule 11 outputs a fixed preset voltage.

[0096] Exemplarily, in the case where the bias voltage needs to be changed by adjusting the output voltage of the first voltage stabilizing submodule 11, the second resistor 112 can be a resistor with a fixed resistance, and the third resistor 113 and / or the fourth resistor 114 can be an adjustable resistor. Based on this, the controller 30 can change the node voltage at the other end of the second resistor 112 by adjusting the resistance of the third resistor 113 and / or the fourth resistor 114, that is, adjust the output voltage of the first voltage stabilizing submodule 11, so as to achieve the effect of controlling the output end of the first voltage stabilizing submodule 11 to output the first preset voltage. After the node voltage at the other end of the second resistor 112 is changed, the node voltage can be stabilized at the first preset voltage through the first voltage stabilizing chip 111, so that the first voltage stabilizing submodule 11 can output a stable first preset voltage to avoid voltage floating. Exemplarily, the model of the first voltage stabilizing chip 111 can be TL431.

[0097] It should be noted that the third resistor 113 and / or the fourth resistor 114 may include one resistor or multiple resistors, and the multiple resistors may be connected in series or in parallel; for example: for the fourth resistor 114, the fourth resistor 114 may include two resistors connected in parallel. In this case, it is equivalent to the third resistor 113 being connected in series with the fourth resistor 114 composed of two resistors connected in parallel. When adjusting the output voltage, the output voltage of the first voltage stabilizing submodule 11 can be changed by adjusting the resistance value of the third resistor 113 and at least one of the two resistors connected in parallel.

[0098] In this embodiment, a specific circuit structure of the first voltage stabilizing submodule is provided, which provides a circuit basis for output voltage regulation of the first voltage stabilizing submodule and can improve the reliability and stability of bias voltage regulation.

[0099] In an exemplary embodiment, as shown in FIG5 , a circuit structure diagram of a second voltage stabilizing submodule is provided. The second voltage stabilizing submodule 12 includes a second voltage stabilizing chip 121, a fifth resistor 122, a sixth resistor 123, a seventh resistor 124, and a second capacitor 125; one end of the fifth resistor 122 is connected to the power supply voltage 40, and the other end of the fifth resistor 122 is respectively connected to the output end of the second voltage stabilizing chip 121, one end of the sixth resistor 123, and one end of the second capacitor 125, and the other end of the fifth resistor 122 is the output end of the second voltage stabilizing submodule 12; the input end of the second voltage stabilizing chip 121 is respectively connected to the other end of the sixth resistor 123 and one end of the seventh resistor 124, and the other end of the sixth resistor 123 is connected to one end of the seventh resistor 124; the ground end of the second voltage stabilizing chip 121, the other end of the sixth resistor 123, and the other end of the second capacitor 125 are all grounded.

[0100] Exemplarily, the power supply voltage 40 can be provided by a voltage source VCC, so that the second voltage stabilizing submodule 12 is powered by VCC. VCC can be connected to one end of the fifth resistor 122 in the second voltage stabilizing submodule 12, and the other end of the fifth resistor 122 is respectively connected to the output end of the second voltage stabilizing chip 121, one end of the sixth resistor 123, and one end of the second capacitor 125, and the other end of the fifth resistor 122 can be used as the output end of the second voltage stabilizing submodule 12 to output the second preset voltage, that is, the other end of the fifth resistor 122 is also connected to the anode end of the first diode 22 in the bias current module 20; wherein, the fifth resistor 122 can be used to limit the current of the subsequent circuit.

[0101] In addition, the input end of the second voltage stabilizing chip 121 is respectively connected to the other end of the sixth resistor 123 and one end of the seventh resistor 124, that is, the input end of the second voltage stabilizing chip 121 is connected between the sixth resistor 123 and the seventh resistor 124; the output end of the second voltage stabilizing chip 121 is respectively connected to the other end of the fifth resistor 122, one end of the sixth resistor 123, one end of the second capacitor 125 and the input end (anode end) of the first diode 22; the ground end of the second voltage stabilizing chip 121 is grounded.

[0102] Furthermore, one end of the sixth resistor 123 is respectively connected to the other end of the fifth resistor 122, the output end of the second voltage stabilizing chip 121, one end of the second capacitor 125 and the input end (anode end) of the first diode 22 in the bias current module 20, and the other end of the sixth resistor 123 is respectively connected to one end of the seventh resistor 124 and the input end of the second voltage stabilizing chip 121, and the other end of the seventh resistor 124 is grounded.

[0103] For the first diode 22 in the bias current module 20, the input end (anode end) of the first diode 22 is respectively connected to the other end of the fifth resistor 122, the output end of the second voltage stabilizing chip 121, one end of the sixth resistor 123 and one end of the second capacitor 125; the output end (cathode end) of the first diode 22 is respectively connected to the other end of the first resistor 21, the base of the first transistor 23 and the emitter of the first transistor 23.

[0104] In addition, one end of the second capacitor 125 is respectively connected to the other end of the fifth resistor 122, the output end of the second voltage stabilizing chip 121, one end of the sixth resistor 123 and the input end (anode end) of the first diode 22; the other end of the second capacitor 125 is simultaneously connected to the ground end of the second voltage stabilizing chip 121 and the other end of the seventh resistor 124, and is grounded.

[0105] Exemplarily, based on the circuit structure of the second voltage stabilizing submodule 12 shown in Figure 5, without changing the bias voltage by adjusting the output voltage of the second voltage stabilizing submodule 12, the fifth resistor 122, the sixth resistor 123 and the seventh resistor 124 in the second voltage stabilizing submodule 12 can all be resistors of fixed resistance, so that the output end of the second voltage stabilizing submodule 12 outputs a fixed preset voltage.

[0106] Exemplarily, in the case where the bias voltage needs to be changed by adjusting the output voltage of the second voltage stabilizing submodule 12, the fifth resistor 122 can be a resistor with a fixed resistance, and the sixth resistor 123 and / or the seventh resistor 124 can be an adjustable resistor. Based on this, the controller 30 can change the node voltage at the other end of the fifth resistor 122 by adjusting the resistance of the sixth resistor 123 and / or the seventh resistor 124, that is, adjust the output voltage of the second voltage stabilizing submodule 12, so as to achieve the effect of controlling the output end of the second voltage stabilizing submodule 12 to output the second preset voltage. After the node voltage at the other end of the fifth resistor 122 is changed, the node voltage can be stabilized at the second preset voltage through the second voltage stabilizing chip 121, so that the second voltage stabilizing submodule 12 can output a stable second preset voltage to avoid voltage floating. Exemplarily, the model of the second voltage stabilizing chip 121 can be TL431.

[0107] It should be noted that the sixth resistor 123 and / or the seventh resistor 124 may include one resistor or multiple resistors, and the multiple resistors may be connected in series or in parallel; for example: for the seventh resistor 124, the seventh resistor 124 may include two resistors connected in parallel. In this case, it is equivalent to connecting the sixth resistor 123 in series with the seventh resistor 124 composed of two resistors connected in parallel. When adjusting the output voltage, the output voltage of the second voltage stabilizing submodule 12 can be changed by adjusting the resistance value of the sixth resistor 123 and at least one of the two resistors connected in parallel.

[0108] In this embodiment, a specific circuit structure of the second voltage stabilizing submodule is provided, which provides a circuit basis for output voltage regulation of the second voltage stabilizing submodule and can improve the reliability and stability of bias voltage regulation.

[0109] In combination with the circuit structure of the bias current circuit shown in FIG. 1 to FIG. 5, it is assumed that the first voltage stabilizing submodule 11 in the bias current circuit is used to ensure the stable output of a high voltage, for example, the high voltage may be +12V, and the second voltage stabilizing submodule 12 in the bias current circuit is used to ensure the stable output of a low voltage, for example, the low voltage may be +5V, then the bias voltage U is 12V-5V=7V, and then the base current I of the first transistor 23 can be changed by the first resistor 21. b , that is, the base current I of the first transistor 23 b =U / R 21 , where U is the bias voltage, R 21 is the resistance value of the first resistor 21; further, due to the current amplification effect of the first transistor 23, the collector current I of the first transistor 23 c =βI b , where β is the gain factor of the first transistor 23. The collector current I of the first transistor 23 c That is the bias current I0 output by the bias current circuit.

[0110] Based on the bias current circuit in each of the above embodiments, the bias current circuit can be introduced into the current sensor, so that the current sensor can work in different working states to meet the current detection requirements of different working scenarios. It should be noted that the bias current circuit can also be applied to other power electronic devices to provide different bias currents, and the embodiments of the present application do not specifically limit this.

[0111] The following takes the current sensor as a fluxgate current sensor as an example to describe in detail the fluxgate current sensor with a bias current circuit added, that is, a fluxgate current sensor with a stable and adjustable bias current can be obtained. Among them, the fluxgate current sensor has a wide range of application scenarios because of its high sensitivity, small temperature drift and high reliability, and can accurately reflect current changes.

[0112] Fig. 6 is a schematic diagram of the structure of the fluxgate current sensor provided by the embodiment of the present application. As shown in Fig. 6, the fluxgate current sensor may include a flux detection circuit 61, a zero point debugging circuit 62, an output comparison and push-pull output circuit 63 and an anti-current backflow circuit 64. The fluxgate current sensor with a stable and adjustable bias current may also include a bias current circuit 65 in any of the above embodiments; wherein the flux detection circuit 61, the zero point debugging circuit 62 and the output comparison and push-pull output circuit 63 are connected in sequence, and the output comparison and push-pull output circuit 63 and the bias current circuit 65 are respectively connected to the anti-current backflow circuit 64; based on this, the output current of the anti-current backflow circuit 64 is the sum of the compensation current output by the output comparison and push-pull output circuit 63 and the target bias current output by the bias current circuit 65.

[0113] Exemplarily, when there is no input current to the fluxgate current sensor, the compensation current I output by the output comparison and push-pull output circuit 63 in the fluxgate current sensor is S is 0. At this time, the output current of the current backflow prevention circuit 64 is the compensation current I output by the output comparison and push-pull output circuit 63. S The sum of the target bias current I0 output by the bias current circuit 65 is the compensation current I S is 0, therefore, in the absence of input current, the output current of the current backflow prevention circuit 64 (that is, the output current of the fluxgate current sensor) is the target bias current I0 output by the bias current circuit 65, therefore, the target bias current I0 can also be called the zero-point bias current.

[0114] Figure 7 shows a schematic diagram of the circuit structure of a magnetic flux detection circuit. As shown in Figure 7, the magnetic flux detection circuit 61 may include a magnetic sensitive chip 611, an eighth resistor 612 and a ninth resistor 613, wherein one end of the eighth resistor 612 is grounded, and the other end of the eighth resistor 612 is connected to the first end of the magnetic sensitive chip 611; one end of the ninth resistor 613 is connected to a +5V power supply, and the other end of the ninth resistor 613 is connected to the second end of the magnetic sensitive chip 611; the first output terminal OUT and the second output terminal REF of the magnetic sensitive chip 611 are respectively connected to the input terminal of the zero point debugging circuit 62, for outputting a set of differential voltage signals for the zero point debugging circuit 62.

[0115] Exemplarily, the +5V voltage source can supply precise and stable power to the magnetic sensor chip 611. The magnetic sensor chip 611 can output differential voltage signals OUT and REF by sensing the magnetic field of the induction coil.

[0116] FIG. 8 shows a schematic circuit diagram of a zero - point debugging circuit. As shown in FIG. 8, the zero - point debugging circuit 62 can include a tenth resistor 621, an eleventh resistor 622, a twelfth resistor 623, and a thirteenth resistor 624. Among them, one end of the tenth resistor 621 is connected to the first output terminal OUT of the magnetic flux detection circuit 61, and the other end of the tenth resistor 621 is connected to one end of the twelfth resistor 623 and serves as the first output terminal OUT1 of the zero - point debugging circuit 62; one end of the eleventh resistor 622 is connected to the second output terminal REF of the magnetic flux detection circuit 61, and the other end of the eleventh resistor 622 is connected to one end of the thirteenth resistor 624 and serves as the second output terminal OUT2 of the zero - point debugging circuit 62; one end of the twelfth resistor 623 is connected to the other end of the tenth resistor 621, and the other end of the twelfth resistor 623 is grounded; one end of the thirteenth resistor 624 is connected to the other end of the eleventh resistor 622, and the other end of the thirteenth resistor 624 is grounded.

[0117] Exemplarily, the first output terminal OUT1 of the zero - point debugging circuit 62 is related to the first output terminal OUT of the magnetic flux detection circuit 61, and the second output terminal OUT2 of the zero - point debugging circuit 62 is related to the second output terminal REF of the magnetic flux detection circuit 61. When the output voltage OUT of the magnetic flux detection circuit 61 > REF, the differential voltage OUT1 of the corresponding zero - point debugging circuit 62 > OUT2; when the output voltage OUT of the magnetic flux detection circuit 61 < REF, the differential voltage OUT1 of the corresponding zero - point debugging circuit 62 < OUT2.

[0118] Exemplarily, the resistance value of at least one of the tenth resistor 621, the eleventh resistor 622, the twelfth resistor 623, and the thirteenth resistor 624 in the zero - point debugging circuit 62 is adjustable. When there is no待测电流输入 (input of the current to be measured), it is ensured that the voltages of the first output terminal OUT1 and the second output terminal OUT2 of the zero - point debugging circuit 62 are equal, and the subsequent output comparison and push - pull output circuit 63 is not turned on, that is, no current flows through the output comparison and push - pull output circuit 63, so that the compensation current I output by the output comparison and push - pull output circuit 63 S is 0.

[0119] It should be noted that the Chinese phrase "待测电流输入" is directly translated as "input of the current to be measured" here, but it might be better to use a more standard or commonly used term if there is one in the relevant technical field. Also, the text has some potential issues with grammar and clarity in the original Chinese, which are carried over to the translation as accurately as possible.Figure 9 shows a schematic diagram of the circuit structure of an output comparison and push-pull output circuit. As shown in Figure 9, the output comparison and push-pull output circuit 63 may include an operational amplifier 631, a third capacitor 632, a fourth capacitor 633, a fourteenth resistor 634, a second transistor 635, a third transistor 636 and an inductor 637; wherein, the positive input pin of the operational amplifier 631 is connected to the first output terminal OUT1 of the zero point debugging circuit 62, the negative input pin of the operational amplifier 631 is connected to the second output terminal OUT2 of the zero point debugging circuit 62, the output terminal of the operational amplifier 631 is respectively connected to one end of the fourteenth resistor 634, the base b of the second transistor 635 and the base b of the third transistor 636, the positive side power supply pin of the operational amplifier 631 is connected to the +15V voltage source, and the negative side power supply pin of the operational amplifier 631 is connected to the -15V voltage source.

[0120] The third capacitor 632 is connected to power pins at both sides of the operational amplifier 631 , that is, one end is connected to the positive power pin of the operational amplifier 631 , and the other end is connected to the negative power pin of the operational amplifier 631 .

[0121] One end of the fourth capacitor 633 is connected to the second output terminal OUT2 of the zero point debugging circuit 62, and the other end of the fourth capacitor 633 is respectively connected to the other end of the fourteenth resistor 634, the emitter e of the second transistor 635, the collector c of the third transistor 636 and one end of the inductor 637.

[0122] One end of the fourteenth resistor 634 is respectively connected to the output end of the operational amplifier 631, the base b of the second transistor 635 and the base b of the third transistor 636, and the other end of the fourteenth resistor 634 is respectively connected to the emitter e of the second transistor 635, the collector c of the third transistor 636 and one end of the inductor 637.

[0123] The base b of the second transistor 635 is respectively connected to the output end of the operational amplifier 631, one end of the fourteenth resistor 634 and the base b of the third transistor 636, the collector c of the second transistor 635 is respectively connected to the +15V voltage source, the positive power supply pin of the operational amplifier 631 and one end of the third capacitor 632, and the emitter e of the second transistor 635 is respectively connected to the other end of the fourteenth resistor 634, the collector c of the third transistor 636 and one end of the inductor 637. Exemplarily, the second transistor 635 can be an NPN transistor.

[0124] The base b of the third transistor 636 is respectively connected to the output end of the operational amplifier 631, one end of the fourteenth resistor 634 and the base b of the second transistor 635, the collector c of the third transistor 636 is respectively connected to the other end of the fourteenth resistor 634, the emitter e of the second transistor 635 and one end of the inductor 637, and the emitter e of the third transistor 636 is respectively connected to the -15V voltage source, the negative side power supply pin of the operational amplifier 631 and the other end of the third capacitor 632. Exemplarily, the third transistor 636 can be a PNP transistor.

[0125] One end of the inductor 637 is respectively connected to the other end of the fourteenth resistor 634, the emitter e of the second transistor 635, the collector c of the third transistor 636 and the other end of the fourth capacitor 633. The other end of the inductor 637 is the current output end of the output comparison and push-pull output circuit 63, which is used to output the compensation current I S .

[0126] Based on the circuit structure diagram of the output comparison and push-pull output circuit 63 shown in Figure 9, the output comparison and push-pull output circuit 63 can be used to act on the flux detection circuit 61 through magnetic field feedback when a current to be measured flows through it, so as to ensure that the differential voltage output by the flux detection circuit 61 is zero.

[0127] Exemplarily, when the current to be detected is input to the magnetic flux detection circuit 61, the operational amplifier 631 in the output comparison and push-pull output circuit 63 is used to generate a compensation magnetic field on the secondary coil (i.e., the inductor 637) according to the magnitude of the current to be detected, and output a compensation current I S , thereby canceling the primary magnetic field generated by the magnetic flux detection circuit 61, so that the circuit reaches a dynamic equilibrium state. When the current to be detected is zero, the zero-point debugging circuit 62 acts to make the voltage of the first output terminal OUT1 and the second output terminal OUT2 of the zero-point debugging circuit 62 equal, so that the operational amplifier 631 in the output comparison and push-pull output circuit 63 has no differential voltage, and the output voltage of the operational amplifier 631 is zero, and the compensation current I output by the output comparison and push-pull output circuit 63 is Sis zero; when a positive current to be detected is applied, the first output terminal OUT and the second output terminal REF of the magnetic flux detection circuit 61 output a positive voltage, that is, OUT>REF. Then, the voltage between the first output terminal OUT1 and the second output terminal OUT2 of the zero-point debugging circuit 62 is positive, that is, OUT1>OUT2. Therefore, the voltage across the operational amplifier 631 in the output comparison and push-pull output circuit 63 is positive, the output voltage is greater than 0, the second triode 635 conducts, and the third triode 636 turns off; when a negative current to be detected is applied, the first output terminal OUT and the second output terminal REF of the magnetic flux detection circuit 61 output a reverse voltage, that is, OUT<REF. Then, the voltage between the first output terminal OUT1 and the second output terminal OUT2 of the zero-point debugging circuit 62 is negative, that is, OUT1<OUT2. Therefore, the voltage across the operational amplifier 631 in the output comparison and push-pull output circuit 63 is negative, the output voltage is less than 0, the third triode 636 conducts, and the second triode 635 turns off; when the second triode 635 or the third triode 636 conducts, the inductor 637 in the output comparison and push-pull output circuit 63 is energized to generate a compensation magnetic field, and a compensation current I is output. S ; the compensation magnetic field cancels out the primary magnetic field generated by the magnetic flux detection circuit 61, and the circuit is in a dynamic equilibrium state. The output compensation current I S tends to be stable.

[0128] It should be noted that when the voltage across the operational amplifier 631 in the output comparison and push-pull output circuit 63 is not 0, a current flows through the fourteenth resistor 634 at the output terminal of the operational amplifier 631 and then flows to the inductor 637, which can accelerate the current on the inductor 637, enable the inductor 637 to generate a compensation magnetic field faster, and accelerate the intensity of the compensation magnetic field to cancel out the primary magnetic field at a faster speed, achieving a fast dynamic equilibrium.

[0129] FIG10 shows a schematic diagram of the circuit structure of a current backflow prevention circuit. As shown in FIG10 , the current backflow prevention circuit 64 may include a second diode 641, a third diode 642 and a fifteenth resistor 643; wherein the input end (anode end) of the second diode 641 is connected to the output end of the output comparison and push-pull output circuit 63, that is, the other end of the inductor 637, and the output end (cathode end) of the second diode 641 is connected to the output end (cathode end) of the third diode 642 and one end of the fifteenth resistor 643 respectively; the input end (anode end) of the third diode 642 is connected to the output end (cathode end) of the third diode 642 and one end of the fifteenth resistor 643; ) is connected to the output end of the bias current circuit 65, the output end of the bias current circuit 65 is the collector of the first transistor 23, the output end (cathode end) of the third diode 642 is respectively connected to the output end (cathode end) of the second diode 641 and one end of the fifteenth resistor 643; one end of the fifteenth resistor 643 is respectively connected to the output end (cathode end) of the second diode 641 and the output end (cathode end) of the third diode 642, the other end of the fifteenth resistor 643 serves as the output end of the fluxgate current sensor, and is used to output the measurement current I corresponding to the current to be detected out .

[0130] Exemplarily, the second diode 641 and the third diode 642 are used to prevent the measurement current output by the fluxgate current sensor from flowing back into the upper circuit, causing damage to the upper circuit components, wherein the upper circuit at least includes an output comparison and push-pull output circuit 63 and a bias current circuit 65; in addition, the fifteenth resistor 643 can be used as a current limiting resistor to limit the current size of the measurement current.

[0131] The fluxgate current sensor in this embodiment is added with a bias current circuit, which can provide a bias current of a certain value for the fluxgate current sensor; by adjusting the bias current output by the bias current circuit, different measurement currents output by the fluxgate current sensor can be obtained, so that the fluxgate current sensor can work in different working states and meet the working requirements of different scenarios. In addition, in the fluxgate current sensor with adjustable bias current in this example, the bias current circuit adopts a voltage stabilizing chip to design a voltage stabilizing circuit, and the circuit structure is simple, which can ensure the output of accurate and adjustable stable voltage, ensure the stability of the output bias current, that is, can improve the stability of the bias current. Furthermore, the bias current circuit adopts a method of adjusting the bias voltage to achieve the adjustment of the bias current. Compared with the method of adjusting the bias resistor, it can expand the adjustment range of the bias current, maximize the arbitrary adjustment of the bias current, and improve the applicable range of the adjustable bias current.

[0132] In an exemplary embodiment, as shown in FIG11 , a control method is also provided, which is described by taking the method applied to the fluxgate current sensor in FIGS. 6 to 10 as an example, and includes the following steps 1102 to 1106. Exemplarily, the method can be applied to a controller in a fluxgate current sensor, or to other processors in the fluxgate current sensor other than the controller, etc., which are not specifically limited in the embodiments of the present application. Among them:

[0133] Step 1102, obtaining a target bias current.

[0134] Exemplarily, the fluxgate current sensor may include a display screen, in which an adjustment component for the bias current may be displayed. The adjustment component may be an input component, a selection component, or other forms of adjustment components, such as a physical adjustment component, etc. Through the adjustment component, a desired target bias current may be input so that the fluxgate current sensor can obtain the target bias current.

[0135] Exemplarily, the fluxgate current sensor may also include a communication component, which can communicate and interact with an external control device; based on this, the fluxgate current sensor can obtain the target bias current sent by the control device through the communication component, that is, the user can set the desired target bias current through the control device, and control and adjust the bias current in the fluxgate current sensor through the control device.

[0136] Step 1104, adjusting the bias voltage module in the bias current circuit according to the target bias current to control the bias voltage module to output a preset bias voltage corresponding to the target bias current, so that the bias current module in the bias current circuit outputs the target bias current under the action of the preset bias voltage.

[0137] Exemplarily, when the target bias current is obtained, the preset bias voltage corresponding to the target bias current can be determined according to the target bias current. Of course, the resistance value of the resistor to be adjusted corresponding to the preset bias voltage can be further determined. The resistor to be adjusted can include the third resistor and the fourth resistor in the first voltage stabilizing submodule, and at least one of the sixth resistor and the seventh resistor in the second voltage stabilizing submodule. Furthermore, the output voltage of the bias voltage module can be adjusted according to the preset bias voltage or the resistance value of the resistor to be adjusted, so that the bias voltage module outputs the preset bias voltage corresponding to the target bias current; on this basis, the bias current module can output the target bias current under the action of the preset bias voltage.

[0138] Exemplarily, when adjusting the bias current of the bias current circuit based on the target bias current, the bias voltage and the corresponding bias resistor (i.e., the first resistor 21 in the bias current module) can also be determined according to the target bias current, so that the bias current module outputs the target bias current by adjusting the bias voltage and the bias resistor at the same time.

[0139] Step 1106, input the current to be detected into the flux detection circuit, and obtain the measurement current corresponding to the current to be detected output by the current backflow prevention circuit; the measurement current is the sum of the compensation current output by the output comparison and push-pull output circuit when reaching a dynamic equilibrium state and the target bias current output by the bias current circuit.

[0140] Exemplarily, when the target bias current is adjusted, the current to be detected may be introduced into the fluxgate current sensor so that the fluxgate current sensor outputs a measurement current corresponding to the current to be detected.

[0141] It should be noted that the above-mentioned process of adjusting the bias current, i.e., step 1102 and step 1104, can also adjust or modify the bias current output by the bias current circuit during the process of the fluxgate current sensor measuring the current to be detected, so that the fluxgate current sensor outputs a measurement current corresponding to the current to be detected after the bias current is adjusted.

[0142] In the above control method, when using a fluxgate current sensor for current measurement, the bias current output by the bias current circuit in the fluxgate current sensor can be adjusted first to meet the target bias current expected by the user, and then the current measurement can be performed based on the fluxgate current sensor after the bias current adjustment; of course, the bias current can also be adjusted during the current measurement process to obtain the measurement current expected by the user. This method can realize current measurement with adjustable bias current, thereby meeting the current measurement requirements of different scenarios and improving the applicable scenarios and scope of current measurement.

[0143] In an exemplary embodiment, a complete control method for a fluxgate current sensor with stable and adjustable bias current is provided, which may include the following steps:

[0144] Step S1 : A current to be detected is supplied to a fluxgate current sensor, and the current to be detected generates a primary magnetic field in a coil of a flux detection circuit.

[0145] Step S2: once the existence of the coil magnetic field is detected, the magnetic sensing chip in the magnetic flux detection circuit outputs a differential voltage signal from the first output terminal OUT and the second output terminal REF of the magnetic sensing chip.

[0146] Step S3: The zero - point debugging circuit receives the differential voltage signal output by the magnetic - sensitive chip and outputs the differential voltage signal from the first output terminal OUT1 and the second output terminal OUT2 of the zero - point debugging circuit. If the voltage OUT > REF, then the output voltage OUT1 > OUT2; if the voltage OUT < REF, then the output voltage OUT1 < OUT2.

[0147] Step S4: When there is no current to be detected input, adjust the resistance value in the zero - point debugging circuit to make OUT1 = OUT2, so that the subsequent circuit is not turned on.

[0148] Step S5: Once the voltages of OUT1 and OUT2 output by the zero - point debugging circuit are detected, the output comparison and push - pull output circuit enters the working state. If the voltages at both ends of OUT1 and OUT2 of the operational amplifier are positive, the second triode conducts; if the voltages at both ends of OUT1 and OUT2 of the operational amplifier are negative, the third triode conducts. After the second triode or the third triode conducts, a compensating magnetic field is induced in the inductor coil, and a compensating current I is output. s This compensating magnetic field cancels out the primary magnetic field to reach a dynamic equilibrium state.

[0149] Step S6: By adjusting the resistance value of the adjustable resistor in the bias current circuit, the first voltage - stabilizing chip and the second voltage - stabilizing chip in the bias current circuit can stably output a high voltage (such as + 12V) and a low voltage (+ 5V) respectively, so as to generate a bias voltage U = 7V. Then the base current I of the first triode b = U / R 21 The collector current I of the first triode c = I o = βI b .

[0150] By adjusting the resistance value of the adjustable resistor in the bias current circuit, the magnitude of the bias voltage can be changed. After the current amplification effect of the triode, the adjustment of the bias current can be finally realized.

[0151] Step S7: The output comparison and push - pull output circuit outputs a compensating current I s , the bias current circuit outputs a bias current I o , then the fluxgate current sensor outputs a measured current I out = I s + I o ; In addition, the second diode and the third diode in the anti - current - backflow circuit both have the characteristic of unidirectional conduction, which can prevent the measured current I out from flowing backward to the upper - level circuit, thus damaging the devices of the upper - level circuit.

[0152] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0153] In the embodiments provided in the present application, it should be understood that the division of units is merely a logical function division, and there may be other division methods in actual implementation, for example, multiple units may be combined into one unit, one unit may be split into multiple units, or some features may be ignored.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A bias current circuit, characterized in that: include: A bias voltage module, a bias current module and a controller, wherein the input end of the bias voltage module is connected to the supply voltage, the output end of the bias voltage module is connected to the input end of the bias current module, and the controller is connected to the bias voltage module; The controller is used to control the bias voltage module to output a preset bias voltage; The bias current module is used to output a target bias current corresponding to the preset bias voltage under the action of the preset bias voltage.

2. The bias current circuit according to claim 1, characterized in that: The bias voltage module includes: a first voltage stabilizing submodule and a second voltage stabilizing submodule, wherein the input end of the first voltage stabilizing submodule is connected to the power supply voltage, and the output end of the first voltage stabilizing submodule is connected to the first input end of the bias current module; the input end of the second voltage stabilizing submodule is connected to the power supply voltage, and the output end of the second voltage stabilizing submodule is connected to the second input end of the bias current module; The controller is used to control the first voltage stabilizing submodule to output a first preset voltage, and / or control the second voltage stabilizing submodule to output a second preset voltage, and the difference between the first preset voltage and the second preset voltage is the preset bias voltage.

3. The bias current circuit according to claim 2, characterized in that: The bias current module comprises: a first resistor, a first diode and a first transistor, one end of the first resistor is a first input end of the bias current module, an input end of the first diode is a second input end of the bias current module, and a collector of the first transistor is an output end of the bias current module; The other end of the first resistor is respectively connected to the output end of the first diode, the base of the first transistor and the emitter of the first transistor; the output end of the first diode is connected to the base of the first transistor.

4. The bias current circuit according to claim 3, characterized in that: The target bias current is the output current of the collector of the first transistor, the output current of the collector of the first transistor is the product of the input current of the base of the first transistor and the amplification factor of the first transistor, and the input current of the base of the first transistor is the ratio of the preset bias voltage to the resistance value of the first resistor.

5. The bias current circuit according to claim 2, characterized in that: The first voltage stabilizing submodule includes a first voltage stabilizing chip, a second resistor, a third resistor, a fourth resistor and a first capacitor; One end of the second resistor is connected to the supply voltage, the other end of the second resistor is respectively connected to the output end of the first voltage stabilizing chip, one end of the third resistor and one end of the first capacitor, and the other end of the second resistor is the output end of the first voltage stabilizing submodule; The input end of the first voltage stabilizing chip is respectively connected to the other end of the third resistor and one end of the fourth resistor, and the other end of the third resistor is connected to one end of the fourth resistor; A grounding terminal of the first voltage stabilizing chip, the other end of the fourth resistor, and the other end of the first capacitor are all grounded.

6. The bias current circuit according to claim 5, characterized in that: The controller is used to adjust the resistance value of the third resistor and / or the resistance value of the fourth resistor to control the output end of the first voltage stabilizing submodule to output the first preset voltage.

7. The bias current circuit according to claim 2, characterized in that: The second voltage stabilizing submodule includes a second voltage stabilizing chip, a fifth resistor, a sixth resistor, a seventh resistor and a second capacitor; One end of the fifth resistor is connected to the supply voltage, the other end of the fifth resistor is respectively connected to the output end of the second voltage stabilizing chip, one end of the sixth resistor and one end of the second capacitor, and the other end of the fifth resistor is the output end of the second voltage stabilizing submodule; The input end of the second voltage stabilizing chip is respectively connected to the other end of the sixth resistor and one end of the seventh resistor, and the other end of the sixth resistor is connected to one end of the seventh resistor; A ground terminal of the second voltage stabilizing chip, the other end of the sixth resistor, and the other end of the second capacitor are all grounded.

8. The bias current circuit according to claim 7, characterized in that: The controller is used to adjust the resistance value of the sixth resistor and / or the resistance value of the seventh resistor to control the output end of the second voltage stabilizing submodule to output the second preset voltage.

9. A fluxgate current sensor, comprising a flux detection circuit, a zero point debugging circuit, an output comparison and push-pull output circuit and a current backflow prevention circuit, characterized in that: Also comprising: a bias current circuit as claimed in any one of claims 1 to 8; The magnetic flux detection circuit, the zero point debugging circuit and the output comparison and push-pull output circuit are connected in sequence, and the output comparison and push-pull output circuit and the bias current circuit are connected to the current backflow prevention circuit respectively; The output current of the current backflow prevention circuit is the sum of the compensation current output by the output comparison and push-pull output circuit and the target bias current output by the bias current circuit.

10. A control method, characterized in that: Applied to the fluxgate current sensor as claimed in claim 9, the method comprises: Get the target bias current; According to the target bias current, adjusting the bias voltage module in the bias current circuit to control the bias voltage module to output a preset bias voltage corresponding to the target bias current, so that the bias current module in the bias current circuit outputs the target bias current under the action of the preset bias voltage; The current to be detected is input into the magnetic flux detection circuit, and the measurement current corresponding to the current to be detected output by the current backflow prevention circuit is obtained; the output current is the sum of the compensation current output by the output comparison and push-pull output circuit when a dynamic balance is reached and the target bias current output by the bias current circuit.

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