CN211528520U - Current sampling circuit based on Hall sensor - Google Patents
Current sampling circuit based on Hall sensor Download PDFInfo
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- CN211528520U CN211528520U CN201922020799.1U CN201922020799U CN211528520U CN 211528520 U CN211528520 U CN 211528520U CN 201922020799 U CN201922020799 U CN 201922020799U CN 211528520 U CN211528520 U CN 211528520U
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- pole double
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Abstract
The utility model discloses a current sampling circuit based on hall sensor, including first two operational amplifier, first two diodes and first two single-pole double throw electronic switch, wherein the normal phase input of first operational amplifier and the inverting input of second operational amplifier all link to each other with hall element's output, the output of first operational amplifier links to each other with an input pin of control unit through first diode, first single-pole double throw electronic switch, the negative pole of first diode connects to the inverting input through the second resistance; the positive phase input end of the second operational amplifier is grounded through a fifth resistor, the output end of the second operational amplifier is connected with the other input pin of the control unit through a second diode and a second single-pole double-throw electronic switch, and the cathode of the second diode is connected to the negative phase input end through a sixth resistor. The utility model discloses a two AD mouth samplings, sampling resolution ratio are 0.033V and correspond 1A electric current, make the sampling precision improve one time, simple structure, it is with low costs.
Description
Technical Field
The utility model relates to a current sampling device specifically is a current sampling circuit based on hall sensor.
Background
At present, Hall current sampling is used in a plurality of industrial products, but because the temperature and the single chip microcomputer and the conversion of each intermediate link of the conversion unit have large sampling errors, the calculation accuracy of some industrial equipment can be greatly influenced, such as an electric energy meter, battery SOC calculation, an ACDC power supply and the like. The Hall current transformer generally supplies power for positive and negative, the current is positive and negative current, and the feedback supplies power for positive and negative voltage.
The traditional current testing circuit is shown in fig. 1, two operational amplifiers are connected in series, Hall feedback voltage is divided into positive and negative 1.5V voltage by resistors R1 and R2 and converted into a first operational amplifier A1, the voltage is raised to 0-3V by a 1.5V voltage-regulator tube ZV1, and the voltage is output to a single chip microcomputer by a follower of a second operational amplifier A2. Because the singlechip generally can not discern the negative voltage, general singlechip sampling range is 0 ~ 3.3V. So that the positive and negative hall signals need to be all positively charged through the operational amplifier. The Hall signal can be normally collected only by AD sampling of the singlechip, so that the final conversion voltage of the conversion circuit is 0-3V. For example, no current passes through the Hall, the single chip microcomputer acquires an AD value corresponding to 1.5V voltage, and if the current is 100A in the forward direction, the single chip microcomputer acquires an AD value corresponding to 3V; if the voltage is negative 100A, the voltage of 0V is adopted by the single chip microcomputer. 0-3V corresponds to 200A current, namely 200A current is acquired by the circuit in the same AD value sampling range, and the sampling resolution is 0.015V corresponding to 1A current; if the traditional sampling mode is adopted, the current is changed into 100A current with positive direction corresponding to 0-3V and 100A current with negative direction corresponding to 0-3V, and the sampling resolution is 0.033V and 1A current. It can be seen that the conversion circuit shown in fig. 1 sacrifices much sampling accuracy.
SUMMERY OF THE UTILITY MODEL
To current test circuit among the prior art can sacrifice very big current sampling precision when voltage conversion etc. not enough, the to-be-solved problem of the utility model is to provide a can improve current sampling circuit based on hall sensor of sampling precision
In order to solve the technical problem, the utility model discloses a technical scheme is:
the utility model relates to a current sampling circuit based on hall sensor, including first two operational amplifier, first two diodes and first two single-pole double throw electronic switch, wherein the normal phase input of first operational amplifier and the inverting input of second operational amplifier all link to each other with hall element's output, the output of first operational amplifier links to each other with an input pin of the control unit through first diode, first single-pole double throw electronic switch, the negative pole of first diode connects to the inverting input through the second resistance; the positive phase input end of the second operational amplifier is grounded through a fifth resistor, the output end of the second operational amplifier is connected with the other input pin of the control unit through a second diode and a second single-pole double-throw electronic switch, and the cathode of the second diode is connected to the negative phase input end through a sixth resistor.
A first resistor is arranged between the output end of the Hall element and the positive phase input end of the first operational amplifier; and a fifth resistor is arranged between the output end of the Hall element and the inverting input end of the second operational amplifier.
A node between the cathode of the first diode and the first single-pole double-throw electronic switch is grounded through a third resistor; and a node between the cathode of the second diode and the second single-pole double-throw electronic switch is grounded through a third resistor.
One movable contact of the first single-pole double-throw electronic switch is connected to the cathode of the first diode, the other movable contact of the first single-pole double-throw electronic switch is grounded, and the fixed contact of the first single-pole double-throw electronic switch is connected with one input pin of the control unit; one movable contact of the second single-pole double-throw electronic switch is connected to the cathode of the second diode, the other movable contact is grounded, and the fixed contact is connected with the other input pin of the control unit.
The utility model has the following beneficial effects and advantages:
1. the utility model discloses the circuit knot is handled hall element's input positive and negative going signal separation respectively, adopts two AD mouth samplings, makes 0 ~ 3V correspond positive 100A electric current and 0 ~ 3V correspond negative 100A, and sampling resolution ratio is 0.033V and corresponds 1A electric current, makes the sampling precision double like this.
2. The utility model discloses simple structure puts the requirement not high to the fortune, and rail-to-rail fortune is put and is put all can to use with non-rail-to-rail fortune, if the more ability reduce cost is put to the fortune that uses non-rail-to-rail.
Drawings
FIG. 1 is a schematic diagram of a conventional test circuit;
fig. 2 is a schematic diagram of the test circuit structure of the present invention.
Detailed Description
The invention will be further explained with reference to the drawings attached to the specification.
As shown in fig. 2, the utility model relates to a current sampling circuit based on hall sensor, including first two operational amplifier A1 ~ A2, first two diode D1 ~ D2 and first two single-pole double throw electronic switch K1-1 ~ K1-2, wherein the normal phase input of first operational amplifier A1 and the inverting input of second operational amplifier A2 all link to each other with hall element H's output, the output of first operational amplifier A1 is through first diode D1, first single-pole double throw electronic switch K1-1 links to each other with an input pin of control unit, the negative pole of first diode D1 connects to the inverting input through second resistance R2; the non-inverting input terminal of the second operational amplifier a2 is grounded via a fifth resistor R5, the output terminal is connected to the other input pin of the control unit via a second diode D2 and a second single-pole double-throw electronic switch K1-2, and the cathode of the second diode D2 is connected to the inverting input terminal via a sixth resistor R6.
A first resistor R1 is arranged between the output end of the Hall element H and the positive phase input end of the first operational amplifier A1; and a fifth resistor R5 is arranged between the output end of the Hall element H and the inverting input end of the second operational amplifier A2. The node between the cathode of the first diode D1 and the first single-pole double-throw electronic switch K1-1 is grounded through a third resistor R3; the node between the cathode of the second diode D2 and the second single-pole double-throw electronic switch K1-2 is grounded via a third resistor R3.
One movable contact of the first single-pole double-throw electronic switch K1-1 is connected to the cathode of the first diode D1, the other movable contact is grounded, and the fixed contact is connected with one input pin of the control unit; one movable contact of the second single-pole double-throw electronic switch K1-2 is connected to the cathode of the second diode D2, the other movable contact is grounded, and the fixed contact is connected with the other input pin of the control unit.
In this embodiment, the Hall element outputs feedback voltages of-3 to + 3V. The control unit adopts a singlechip (specification and model are preferably given, for example), the first diode D1-D2 (4148 is adopted in the embodiment) can avoid that the first operational amplifier A1-A2 are not output from a rail to a rail (namely output from full power supply amplitude), so that the voltage 0 point has deviation; the first resistor R1 and the fifth resistor R5 are current-limiting resistors; the second, fourth, sixth R2, R4 and R6 are all feedback resistors; the third and seventh resistors R3 and R7 are pull-down resistors; the first to the second single-pole double-throw electronic switches K1-1 to K1-2 (controlled by the single chip microcomputer).
The working principle of the utility model is as follows:
after the Hall element H acquires information, if the voltage VH of an output signal is greater than 0V, an output signal is provided at a node IO1 between the cathode of the first diode D1 and the first single-pole double-throw electronic switch K1-1, the output signal is thrown to the output end of the node IO2 through the first single-pole double-throw electronic switch K1-1, the output signal of the node is output to a single chip microcomputer, and meanwhile, the second single-pole double-throw electronic switch K1-2 is thrown to a ground end, so that zero drift can be well limited; the first operational amplifier a1 is used for voltage following, and the first diode D1 is used to avoid the voltage deviation of the first operational amplifier a 1; the data AD1 output by the first operational amplifier A1 enters the singlechip to be subjected to data processing;
after the Hall element H acquires information, if the voltage VH of an output signal is less than 0V, an output signal exists at a node IO2 between the cathode of the second diode D2 and the second single-pole double-throw electronic switch K1-2, the second single-pole double-throw electronic switch K1-2 is thrown to the output end of the node IO2, the output signal of the node is output to the single chip microcomputer, and meanwhile, the first single-pole double-throw electronic switch K1-1 is thrown to the ground end, so that zero drift can be well limited; the second operational amplifier A2 is used for voltage following, and the second diode D2 is used to avoid the voltage deviation of the second operational amplifier A2; the data AD2 data output by the second operational amplifier A2 enter the acquisition single chip microcomputer for data processing;
when the single chip microcomputer processes data, sampling is carried out by ADC times in an equal time division mode for 8 times, and the average value is obtained and is used as the sampling number for carrying out subsequent processing. Because hall element H's input positive and negative direction signal separation handles respectively, adopts two AD mouth samplings, makes 0 ~ 3V correspond positive 100A electric current and 0 ~ 3V and corresponds negative 100A, and sampling resolution ratio is 0.033V and corresponds 1A electric current, and every 1A of AD sampling leads to the sampling voltage variation range big more, and sampling error is less, and the sampling precision is higher more, under the same condition of two peripheral devices of sampling circuit influence, the utility model discloses sampling precision improves one time.
Claims (4)
1. The utility model provides a current sampling circuit based on hall sensor which characterized in that: the circuit comprises a first operational amplifier, a second operational amplifier, a first diode, a second diode and a first single-pole double-throw electronic switch, wherein a positive phase input end of the first operational amplifier and an inverse phase input end of the second operational amplifier are connected with an output end of a Hall element; the positive phase input end of the second operational amplifier is grounded through a fifth resistor, the output end of the second operational amplifier is connected with the other input pin of the control unit through a second diode and a second single-pole double-throw electronic switch, and the cathode of the second diode is connected to the negative phase input end through a sixth resistor.
2. The hall sensor based current sampling circuit of claim 1 wherein: a first resistor is arranged between the output end of the Hall element and the positive phase input end of the first operational amplifier; and a fifth resistor is arranged between the output end of the Hall element and the inverting input end of the second operational amplifier.
3. The hall sensor based current sampling circuit of claim 1 wherein: a node between the cathode of the first diode and the first single-pole double-throw electronic switch is grounded through a third resistor; and a node between the cathode of the second diode and the second single-pole double-throw electronic switch is grounded through a third resistor.
4. The hall sensor based current sampling circuit of claim 1 wherein: one movable contact of the first single-pole double-throw electronic switch is connected to the cathode of the first diode, the other movable contact of the first single-pole double-throw electronic switch is grounded, and the fixed contact of the first single-pole double-throw electronic switch is connected with one input pin of the control unit; one movable contact of the second single-pole double-throw electronic switch is connected to the cathode of the second diode, the other movable contact is grounded, and the fixed contact is connected with the other input pin of the control unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922020799.1U CN211528520U (en) | 2019-11-21 | 2019-11-21 | Current sampling circuit based on Hall sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922020799.1U CN211528520U (en) | 2019-11-21 | 2019-11-21 | Current sampling circuit based on Hall sensor |
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| CN211528520U true CN211528520U (en) | 2020-09-18 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112834804A (en) * | 2020-12-30 | 2021-05-25 | 成都杰启科电科技有限公司 | Low-cost high-precision current acquisition sensor and control method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112834804A (en) * | 2020-12-30 | 2021-05-25 | 成都杰启科电科技有限公司 | Low-cost high-precision current acquisition sensor and control method thereof |
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