CN217561594U - Differential Hall type current sensor - Google Patents
Differential Hall type current sensor Download PDFInfo
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- CN217561594U CN217561594U CN202123369443.2U CN202123369443U CN217561594U CN 217561594 U CN217561594 U CN 217561594U CN 202123369443 U CN202123369443 U CN 202123369443U CN 217561594 U CN217561594 U CN 217561594U
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Abstract
The utility model discloses a difference hall formula current sensor, including first hall sensor H1, second hall sensor H2, sample hold circuit, high frequency modulation circuit and signal amplification circuit, first hall sensor H1 with second hall sensor H2 is located the both sides of electric current wire respectively and first hall sensor H1 with second hall sensor H2's response opposite direction. The utility model discloses a differential Hall formula current sensor, it passes through differential Hall, can effectively let output not influenced by outside common mode signal, has only measured the magnetic field that is produced by the electric current of input to the interference in outside magnetic field has been suppressed.
Description
Technical Field
The utility model belongs to the technical field of current sensor, concretely relates to difference hall formula current sensor.
Background
The traditional isolated Hall current sensor adopts a Hall principle to induce a magnetic field generated by electrifying a coil to calculate the current of the coil, generally adopts a Hall induction point in one direction, but the scheme is easily interfered by an external magnetic field signal, so that an error is generated in the calculation of the current.
Therefore, the above problems are further improved.
SUMMERY OF THE UTILITY MODEL
A primary object of the present invention is to provide a differential hall current sensor, which can effectively prevent the output from being affected by the external common mode signal by means of the differential hall, and only measure the magnetic field generated by the input current, thereby suppressing the interference of the external magnetic field.
In order to achieve the above object, the utility model provides a differential hall formula current sensor, including first hall sensor H1, second hall sensor H2, sample hold circuit, high frequency modulation circuit and signal amplification circuit, wherein:
the first Hall sensor H1 and the second Hall sensor H2 are respectively positioned at two sides of a current lead, and the sensing directions of the first Hall sensor H1 and the second Hall sensor H2 are opposite;
the first hall sensor H1 is electrically connected with a first input end of the operational amplifier A1 of the sample-and-hold circuit through a switch EN2, and the second hall sensor H2 is electrically connected with a second input end of the operational amplifier A1 of the sample-and-hold circuit through the switch EN 1;
the output end of the operational amplifier A1 is electrically connected with the input end of the high-frequency modulation circuit, and the output end of the high-frequency modulation circuit is electrically connected with the input end of the signal amplification circuit.
As a further preferable aspect of the above technical solution, the high frequency modulation circuit includes a first switch group, a second switch group, and a third switch group, and the signal amplification circuit includes an amplifier A2, in which:
the first switch group comprises a switch K11, a switch K12, a switch K13 and a switch K14, the output end of the operational amplifier A1 is electrically connected with the negative input end of the amplifier A2 sequentially through a capacitor C1 and the switch K11, and the joint end of the switch K11 and the amplifier A2 is also electrically connected with the output end of the operational amplifier A1 through the capacitor C2 and the switch K12;
a capacitor C6 and the switch K13 are connected between the negative input end and the output end of the amplifier A2;
and the switch K14 and the capacitor C4 are connected between the positive input end and the output end of the amplifier A2.
As a further preferable technical solution of the above technical solution, the second switch group includes a switch K21, a switch K22, a switch K23, and a switch K24, the switch K21 is connected in parallel to the switch K11, and the switch K22 is connected in parallel to the switch K12;
the switch K24 and the capacitor C4 are connected between the negative input end and the output end of the amplifier A2;
and a switch K23 and a capacitor C6 are connected between the positive input end and the negative input end of the amplifier A2.
As a further preferable technical solution of the above technical solution, the third switch group includes a switch K3, and an output end of the amplifier A2 is electrically connected to the switch K3.
As a further preferable technical solution of the above technical solution, the positive input end of the amplifier A2 is further connected to a reference voltage (Vref), and one end of the switch K3 away from the capacitor C4 is further connected to the reference voltage (Vref) through a capacitor C5.
Drawings
Fig. 1 is a circuit diagram of a differential hall current sensor according to the present invention.
Fig. 2 is an output waveform diagram modulated by the high-frequency modulation circuit of the differential hall current sensor of the present invention.
Fig. 3 is a circuit diagram of a second switch set enabling of the differential hall current sensor of the present invention.
Fig. 4 is a circuit diagram of a first switch set enabling of the differential hall current sensor of the present invention.
Fig. 5 is a circuit diagram of a third switch set enabling of the differential hall current sensor of the present invention.
Detailed Description
The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The basic principles of the invention, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents and other technical solutions without departing from the spirit and scope of the invention.
The utility model discloses a difference hall formula current sensor combines preferred embodiment below, further describes utility model's concrete embodiment.
In the embodiments of the present invention, those skilled in the art will note that the current conducting wire and hall sensor, etc. related to the present invention can be regarded as the prior art.
Preferred embodiments.
The utility model discloses a difference hall formula current sensor, including first hall sensor H1, second hall sensor H2, sample hold circuit, high frequency modulation circuit and signal amplification circuit, wherein:
the first Hall sensor H1 and the second Hall sensor H2 are respectively positioned at two sides of a current lead, and the sensing directions of the first Hall sensor H1 and the second Hall sensor H2 are opposite;
the first hall sensor H1 is electrically connected with a first input end of the operational amplifier A1 of the sample-and-hold circuit through a switch EN2, and the second hall sensor H2 is electrically connected with a second input end of the operational amplifier A1 of the sample-and-hold circuit through the switch EN 1;
the output end of the operational amplifier A1 is electrically connected with the input end of the high-frequency modulation circuit, and the output end of the high-frequency modulation circuit is electrically connected with the input end of the signal amplification circuit.
Specifically, the high-frequency modulation circuit includes a first switch group, a second switch group, and a third switch group, and the signal amplification circuit includes an amplifier A2, in which:
the first switch group comprises a switch K11, a switch K12, a switch K13 and a switch K14, the output end of the operational amplifier A1 is electrically connected with the negative input end of the amplifier A2 sequentially through a capacitor C1 and the switch K11, the common connection end of the switch K11 and the amplifier A2 is also electrically connected with the output end of the operational amplifier A1 through the capacitor C2 and the switch K12 (one end of the switch K12, far away from the operational amplifier A1, is electrically connected with the output end of the amplifier A2 through a capacitor C3);
a capacitor C6 and the switch K13 are connected between the negative input end and the output end of the amplifier A2;
and the switch K14 and the capacitor C4 are connected between the positive input end and the output end of the amplifier A2.
More specifically, the second switch group comprises a switch K21, a switch K22, a switch K23 and a switch K24, wherein the switch K21 is connected in parallel with the switch K11, and the switch K22 is connected in parallel with the switch K12;
the switch K24 and the capacitor C4 are connected between the negative electrode input end and the output end of the amplifier A2;
and a switch K23 and a capacitor C6 are connected between the positive input end and the negative input end of the amplifier A2.
Further, the third switch group comprises a switch K3, and the output end of the amplifier A2 is electrically connected to the switch K3.
Furthermore, the positive input terminal of the amplifier A2 is further connected to a reference voltage (Vref) and the terminal of the switch K3 remote from the capacitor C4 is further connected to the reference voltage (Vref) through a capacitor C5.
Preferably, two hall sensors with opposite sensing directions are positioned on two sides of the current lead, and the magnetic field generated by the passing current enables the two hall plates to generate hall voltages with opposite outputs, namely, hall potential differences with opposite outputs and the same gain are output. And the two groups of differential Hall signals are sampled by a post-stage sampling and holding circuit and then enter a high-frequency modulation circuit and a signal amplification circuit. And performing logic operation and amplification on the differential signals, and finally modulating the high-frequency differential Hall signals by a demodulation circuit to output low-frequency analog signals, thereby realizing the calculation of the current magnitude. When external magnetic field signals interfere, the two Hall disks can generate common-mode levels in the same direction, and because the designed signal amplification circuit only amplifies differential signals, common-mode magnetic interference signals can be offset, so that immunity to external magnetic interference signals is realized.
The high-frequency modulation circuit controls switches EN1 and EN2 to respectively control the selection of Hall signal input ends, when EN1 is opened, the operational amplifier A1 inputs Hall voltage Vin + Voff of the Hall plate 1, and when EN2 is opened, the operational amplifier A1 inputs Hall voltage Vin-Voff of the Hall plate 2, (wherein Voff is offset voltage and common-mode magnetic interference signal of the Hall plate);
amplifying the differential Hall disc signal by an operational amplifier A1 and then respectively outputting A (Vin + Voff) and A (Vin-Voff);
fig. 2 shows an output waveform of a control signal of the high-frequency modulation circuit for the switch group, where K1 is a first switch group, K2 is a second switch group, and K3 is a third switch group.
The low level is active.
When the second switch group is enabled, the circuit is as shown in fig. 3:
the node A maintains the voltage value of VREF due to the feedback loop, and when a Hall signal is input, the output voltage of the operational amplifier is Vref-A (Vin + Voff);
when the first switch set is enabled, the circuit is as shown in fig. 4:
the output voltage of the operational amplifier can be calculated to be ((Vref-A (Vin + Voff)) + (Vref-A (Vin-Voff)))/2;
i.e., vref-a Vin;
when the third switch group is enabled, the circuit is as shown in fig. 5:
when the input end is closed and the output end is opened, the output voltage value of the operational amplifier output Vout is Vref-A Vin, so that the Hall disc offset can be perfectly cancelled, and the suppression effect on the common-mode magnetic interference signal and the offset voltage of the induction element is realized.
It is worth mentioning that the technical features such as the differential hall type current sensor that the patent application relates to should be regarded as prior art, and the concrete structure, the theory of operation and the control mode that may involve, the spatial arrangement mode of these technical features adopt the conventional selection in this field can, should not be regarded as the invention point of the utility model discloses a place, the utility model discloses a do not do further specifically expand the detailed description.
It will be apparent to those skilled in the art that modifications and variations can be made in the above-described embodiments, or some features of the invention may be substituted or omitted, and any modification, substitution, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (5)
1. The differential Hall current sensor is characterized by comprising a first Hall sensor H1, a second Hall sensor H2, a sampling and holding circuit, a high-frequency modulation circuit and a signal amplification circuit, wherein:
the first Hall sensor H1 and the second Hall sensor H2 are respectively positioned at two sides of a current lead, and the sensing directions of the first Hall sensor H1 and the second Hall sensor H2 are opposite;
the first hall sensor H1 is electrically connected with a first input end of an operational amplifier A1 of the sample-and-hold circuit through a switch EN2, and the second hall sensor H2 is electrically connected with a second input end of the operational amplifier A1 of the sample-and-hold circuit through the switch EN 1;
the output end of the operational amplifier A1 is electrically connected with the input end of the high-frequency modulation circuit, and the output end of the high-frequency modulation circuit is electrically connected with the input end of the signal amplification circuit.
2. The differential hall current sensor of claim 1 wherein the high frequency modulation circuit comprises a first switch set, a second switch set, and a third switch set, and the signal amplification circuit comprises an amplifier A2, wherein:
the first switch group comprises a switch K11, a switch K12, a switch K13 and a switch K14, the output end of the operational amplifier A1 is electrically connected with the negative input end of the amplifier A2 sequentially through a capacitor C1 and the switch K11, and the joint end of the switch K11 and the amplifier A2 is also electrically connected with the output end of the operational amplifier A1 through the capacitor C2 and the switch K12;
a capacitor C6 and the switch K13 are connected between the negative electrode input end and the output end of the amplifier A2;
and the switch K14 and the capacitor C4 are connected between the positive input end and the output end of the amplifier A2.
3. The differential hall current sensor of claim 2 wherein the second switch set comprises switch K21, switch K22, switch K23, switch K24, the switch K21 being connected in parallel to the switch K11 and the switch K22 being connected in parallel to the switch K12;
the switch K24 and the capacitor C4 are connected between the negative input end and the output end of the amplifier A2;
and a switch K23 and a capacitor C6 are connected between the positive input end and the negative input end of the amplifier A2.
4. The differential hall current sensor of claim 3 wherein the third switch set comprises switch K3, and wherein the output of amplifier A2 is electrically connected to switch K3.
5. The differential Hall current sensor according to claim 4, wherein said positive input terminal of amplifier A2 is further connected to a reference voltage and said terminal of switch K3 remote from said capacitor C4 is further connected to a reference voltage through a capacitor C5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123369443.2U CN217561594U (en) | 2021-12-29 | 2021-12-29 | Differential Hall type current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123369443.2U CN217561594U (en) | 2021-12-29 | 2021-12-29 | Differential Hall type current sensor |
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| Publication Number | Publication Date |
|---|---|
| CN217561594U true CN217561594U (en) | 2022-10-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123369443.2U Active CN217561594U (en) | 2021-12-29 | 2021-12-29 | Differential Hall type current sensor |
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| Country | Link |
|---|---|
| CN (1) | CN217561594U (en) |
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2021
- 2021-12-29 CN CN202123369443.2U patent/CN217561594U/en active Active
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