阅读说明：本技术 一种可检测双向电流的双霍尔传感器调理电路 (double-Hall sensor conditioning circuit capable of detecting bidirectional current ) 是由 韦清瀚 周文亮 张井超 武建文 陈儒盎 贾博文 于 2020-12-14 设计创作，主要内容包括：本发明公开一种可检测双向电流的双霍尔传感器调理电路,通过开环式霍尔传感器将接触器电流产生的磁场转化为电压信号并使用两组正反双路放大电路放大电压信号以完成检测正反电流的目的。本发明采用对称分布双霍尔元件连接两组正反双路放大电路消除磁场干扰,并利用该电路由电源供电电路,电压放大电路,补偿恒流源电路和霍尔元件等构成的系统温漂的温度采集电路,防短路保护电路组成,通过精确的计算和合理计算可测的最大电流量程可达到±3000A,为霍尔传感器的电流检测提供了新的思路。(The invention discloses a double-Hall sensor conditioning circuit capable of detecting bidirectional current, which converts a magnetic field generated by the current of a contactor into a voltage signal through an open-loop Hall sensor and amplifies the voltage signal by using two groups of positive and negative two-way amplifying circuits so as to fulfill the aim of detecting the positive and negative currents. The invention adopts symmetrically distributed double Hall elements to connect two groups of positive and negative double-path amplifying circuits to eliminate magnetic field interference, and utilizes the temperature acquisition circuit of the system temperature drift formed by a power supply circuit, a voltage amplifying circuit, a compensation constant current source circuit, Hall elements and the like, and an anti-short circuit protection circuit, the measurable maximum current range can reach +/-3000A through accurate calculation and reasonable calculation, and a new idea is provided for the current detection of the Hall sensor.)

1. The utility model provides a two hall sensor conditioning circuit of detectable two-way electric current which characterized in that: the controllable precise voltage-stabilizing power supply TL-431 comprises a controllable precise voltage-stabilizing power supply TL-431, two groups of Hall elements, two proportion amplifying circuits, a 12V direct-current power supply and four OP295 chips U1-U4, wherein each OP295 chip is integrated with two operational amplifiers;

the No. 1 pin and the No. 2 pin of the TL-431 are connected with the No. 2 pin of a 1K omega resistor R7, the No. 1 pin of R7 is connected with a 12V direct current power supply, the No. 3 pin of the TL-431 is grounded, and a 0.1 mu F capacitor is connected between the No. 2 pin and the No. 3 pin of the TL-431 in parallel;

the No. 1 pin of the TL-431 is supplied with power for three branches through the voltage division of 2.5V, wherein two branches are power supply branches of the Hall element A and the Hall element B and are respectively connected into the chips U3 and U4 through the No. 3 pins of the resistors R19 and R26, the U3 and the U4;

the No. 4 pins of U1, U2, U3 and U4 are grounded; no. 8 pins of U1, U2, U3 and U4 are connected to a 12V direct-current power supply anode to supply power to the chip; a capacitor is connected between the No. 8 pin of U3 and the ground, and a capacitor is connected between the No. 8 pin of U4 and the ground; the No. 2 pins of U3 and U4 are grounded through resistors R18 and R25 respectively; meanwhile, the No. 2 pin of U3 and the No. 2 pin of U4 are respectively connected with the input negative terminals of the Hall element A and the Hall element B; the No. 1 pin of U3 and the No. 1 pin of U4 are respectively connected with the power supply positive terminals of the Hall element A and the Hall element B;

in the other branch circuit after voltage division by TL-431, 2.5V voltage completes generation of 0.1V voltage-raising voltage through U4;

pins 5, 6 and 7 of the operational amplifiers in U1 and U2 are connected to an amplifying circuit to amplify the voltage signal.

2. The dual hall sensor conditioning circuit of claim 1 wherein: each OP295 chip is packaged as SO-8.

3. The dual hall sensor conditioning circuit of claim 1 wherein: and one thousandth of precision resistors are adopted for R12, R32 and R33.

4. The dual hall sensor conditioning circuit of claim 1 wherein: the Hall element A is positioned at 0 degree, the Hall element B is positioned at 180 degrees and mutually symmetrical.

5. The dual hall sensor conditioning circuit of claim 1 wherein: in the other branch after voltage division by the TL-431, the 2.5V voltage is firstly connected to the No. 5 pin of the U4 through the resistor R32, and is grounded through the resistor R33, and the voltage of the No. 5 pin is 0.1V through voltage division by the two resistors R32 and R33.

6. The dual hall sensor conditioning circuit of claim 1 wherein: in linear operation, pin 6 of U4 is connected with pin 7 of the output to obtain the voltage of the output to ground of 0.1V.

7. The dual hall sensor conditioning circuit of claim 1 wherein: the connection mode of each operational amplifier and the amplifying circuit in U1 and U2 is as follows:

the No. 2 pin and the No. 3 pin of one operational amplifier in the U1 are respectively connected with the positive output terminal and the negative output terminal of the Hall element A through resistors R8 and R10; a resistor R6 is connected between the No. 1 pin and the No. 2 pin; a resistor R11 is connected between the No. 3 pin and the No. 7 pin of the U4, and the voltage-raising voltage of 0.1V is introduced into the amplifying circuit;

the other operational amplifier in U1 is connected with the positive output terminal U1+ of the Hall element A through a No. 6 pin, and a resistor R14 is connected between the operational amplifier and the positive output terminal U1+ of the Hall element A; a resistor R13 is connected between the No. 6 pin and the No. 7 pin, the No. 5 pin is connected with the output negative end of the Hall element A, and a resistor R16 is connected between the No. 6 pin and the No. 5 pin; the No. 5 pin is connected to a ground lifting voltage, a resistor R17 is connected between the No. 5 pin and the No. 7 pin of the U4, and the ground lifting voltage of 0.1V is introduced into the amplifying circuit;

the No. 2 pin and the No. 3 pin of one operational amplifier in the U2 are respectively connected with the positive output terminal and the negative output terminal of the Hall element B through resistors R21 and R23; a resistor R20 is connected between the No. 1 pin and the No. 2 pin; a resistor R24 is connected between the No. 3 pin and the No. 7 pin of the U4, and the voltage-raising voltage of 0.1V is introduced into the amplifying circuit;

the other operational amplifier in the U2 is connected with the positive output end of the Hall element B through a No. 6 pin, and a resistor R28 is connected between the operational amplifier and the positive output end of the Hall element B; a resistor R27 is connected between the No. 6 pin and the No. 7 pin, the No. 5 pin is connected with the output negative end of the Hall element B, and a resistor R30 is connected between the No. 6 pin and the No. 5 pin; the pin No. 5 is connected with a ground-lifting voltage, and a resistor R31 is connected between the pin No. 7 of the U4, so that the ground-lifting voltage of 0.1V is introduced into the amplifying circuit.

8. The dual hall sensor conditioning circuit that senses bi-directional current as set forth in claim 7, wherein: the output end of each amplifying circuit is connected with a resistor, so that the short circuit caused by the misconnection of the load is prevented.

9. The dual hall sensor conditioning circuit that senses bi-directional current as set forth in claim 7, wherein: the amplification factor of the amplifying circuit is 3 times, and then the resistances of the connected resistors R6, R11, R13, R17, R20, R24, R27 and R31 are the same and 3K omega, and the resistances of the resistors R8, R10, R14, R16, R21, R23, R28 and R30 are three times of the resistances of the resistors 1K omega.

10. The dual hall sensor conditioning circuit that senses bi-directional current as set forth in claim 7, wherein: and a temperature acquisition circuit is also designed, and the system temperature formed by the constant current source circuit, the Hall element and the like is compensated through software.

Technical Field

The invention relates to a double-Hall sensor conditioning circuit capable of detecting bidirectional current, in particular to a symmetrically-distributed open-loop Hall element sensor conditioning circuit capable of detecting a large forward and reverse transient 3000A current of a contactor, which is particularly suitable for contactors with large current passing ranges and detection places with certain volume requirements.

Background

The principle of detecting large current mainly based on the open-loop Hall sensor is that magnetic flux generated by primary current is concentrated in a magnetic loop, and the magnetic flux is converted into a voltage signal through a Hall element to be measured. However, the hall element often has a problem of large temperature drift, interference caused by introducing an external magnetic field due to the structure of the contactor (a permanent magnet and a double-wiring column) and a complex lead system during wiring in the detection process can greatly influence the accuracy of the detected current value, and meanwhile, an operational amplifier adopted in the circuit has two sections, namely a linear region and a saturated region, if the operational amplifier fails to enter the linear region in time during detection, the dynamic response speed is reduced, and meanwhile, errors can be brought to the detection result.

Therefore, under the condition of ensuring small volume, low energy consumption and high response speed, the invention provides the double-Hall sensor conditioning circuit which solves the interference of an external magnetic field through a circuit structure and solves the problem of open-loop type detectable bidirectional current with large temperature drift, which is in urgent need.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an open-loop type double-Hall sensor conditioning circuit capable of detecting bidirectional current, which has the characteristics of capability of detecting 3000A large current of forward and reverse transient states of a contactor, small volume, low energy consumption, high response speed, small temperature drift, capability of solving the interference of an external magnetic field and the like.

A double-Hall sensor conditioning circuit capable of detecting bidirectional current comprises a controllable precise voltage stabilizing source TL-431, two groups of Hall elements, two proportion amplifying circuits, a 12V direct-current power supply and four OP295 chips U1-U4, wherein each OP295 chip is integrated with two operational amplifiers.

The No. 1 pin and the No. 2 pin of the TL-431 are connected with the No. 2 pin of a 1K omega resistor R7, the No. 1 pin of R7 is connected with a 12V direct current power supply, the No. 3 pin of the TL-431 is grounded, and a capacitor of 0.1 mu F is connected between the No. 2 pin and the No. 3 pin of the TL-431 in parallel.

The No. 1 pin of the TL-431 is supplied with power for three branches through the voltage division of 2.5V, wherein two branches are power supply branches of the Hall element A and the Hall element B which are mutually symmetrical, and the power supply branches are respectively connected into the chips U3 and U4 through the No. 3 pins of the resistors R19 and R26, the U3 and the U4.

The No. 4 pins of U1, U2, U3 and U4 are grounded; no. 8 pins of U1, U2, U3 and U4 are connected to a 12V direct-current power supply anode to supply power to the chip; a capacitor is connected between the No. 8 pin of U3 and the ground, and a capacitor is connected between the No. 8 pin of U4 and the ground; the No. 2 pins of U3 and U4 are grounded through resistors R18 and R25 respectively; meanwhile, the No. 2 pin of U3 and the No. 2 pin of U4 are respectively connected with the input negative terminals of the Hall element A and the Hall element B; the No. 1 pin of U3 and the No. 1 pin of U4 are respectively connected with the power supply positive terminals of the Hall element A and the Hall element B.

In the other branch after voltage division by TL-431, 2.5V voltage completes generation of 0.1V voltage-raising voltage through U4.

No. 5, 6 and 7 pins of each operational amplifier in U1 and U2 are connected to an amplifying circuit for amplifying voltage signals, and the output end of each amplifying circuit is connected to a resistor, so that short circuit caused by misconnection of loads is prevented.

The invention is also provided with a temperature acquisition circuit, and a system temperature drift formed by a software compensation constant current source circuit, a Hall element and the like.

The invention has the advantages that:

1. the double-Hall sensor conditioning circuit adopts a 12V single power supply for power supply, wherein the power supply comprises an OP295 chip, the voltage is stabilized to 2.5V through a TL-431 chip, the voltage is precisely divided through two OP295 chips to supply power to a Hall element, and the voltage of 2.5V is 0.1V of the voltage-raising voltage obtained after the voltage passes through the OP295 chip so as to improve dynamic response.

2. According to the double-Hall sensor conditioning circuit, the Hall elements are symmetrically distributed, so that the effect of eliminating the interference of an external magnetic field is achieved.

3. The double-Hall sensor conditioning circuit is 2.5V obtained by voltage stabilization of TL-431 and other voltage stabilization chips, but is not limited to 2.5V. The voltage also supplies power for the temperature detection branch, wherein a platinum resistor is adopted for temperature acquisition so as to compensate the temperature drift of a system formed by a constant current source circuit, a Hall element and the like and reduce the influence of the temperature on current detection.

4. The output end of the proportional amplifying circuit of the double-Hall sensor conditioning circuit is connected with a resistor with the resistance value of 1K omega, so that the short circuit and the circuit damage caused by mistaken connection of a load are prevented.

Drawings

FIG. 1 is a schematic diagram of a dual Hall sensor conditioning circuit for detecting bi-directional current according to the present invention.

FIG. 2 is a schematic diagram showing the distribution of dual Hall elements in the dual Hall sensor conditioning circuit capable of detecting bidirectional current according to the present invention.

Detailed Description

The present invention will be described in further detail below with reference to the accompanying drawings.

The invention discloses a double-Hall sensor conditioning circuit capable of detecting bidirectional current, which comprises a controllable precise voltage-stabilizing source TL-431, two groups of Hall elements, two proportion amplifying circuits, a 12V direct-current power supply, 9 capacitors C5-C13, 27 resistors R7-R33 and four OP295 chips, wherein the two groups of Hall elements are connected with the two proportion amplifying circuits through a voltage-stabilizing circuit; wherein, the R12, the R32 and the R33 adopt one thousandth of precision resistors; two operational amplifiers are integrated into each OP295 chip, and each OP295 chip is packaged into SO-8, namely a patch type 8 pin. Let 4 OP295 chips be U1, U2, U3 and U4, respectively, then chip U1 includes operational amplifiers U1A, U1B, chip U2 includes operational amplifiers U2A, U2B, chip U3 includes operational amplifiers U3A and U3B, and chip U4 includes operational amplifiers U4A and U4B; in addition, in the invention, the U3B is not used in the actual connection, and each pin is empty.

The No. 1 pin and the No. 2 pin of the TL-431 are connected with the No. 2 pin of a 1K omega resistor R7, the No. 1 pin of R7 is connected with a 12V direct current power supply, the No. 3 pin of the TL-431 is grounded, and a 0.1 mu F capacitor C7 is connected in parallel between the No. 2 pin and the No. 3 pin of the TL-431.

The pin 1 of the TL-431 is supplied with power by three branches through a voltage division of 2.5V, wherein two branches are power supply branches of the hall element a and the hall element B, and are respectively connected to the chips U3 and U4 through the resistors R19 and R26 with a resistance value of 1K and the pins 3 of U3A and U4A. As shown in fig. 2, in order to achieve the distribution characteristic of the symmetrical dual hall elements under the combined action of the detected current magnetic field and the interference magnetic field, the hall element a is located at 0 °, and the hall element B is located at 180 °.

The No. 4 pins of U1A, U2A, U3A and U4A are grounded; no. 8 pins of U1A, U2A, U3A and U4A are connected to a 12V direct-current power supply anode to supply power to the chips, so that the chips U1, U2, U3 and U4 work; in addition, a capacitor C9 of 0.1 muF is connected between the No. 8 pin of U3A and the ground, and a capacitor C12 of 0.1 muF is connected between the No. 8 pin of U4A and the ground. The 2 pins of U3A and U4A are grounded via a 270 Ω resistor R18 and R25, respectively. Meanwhile, the No. 2 pin of the U3A and the No. 2 pin of the U4A are respectively connected with the input negative terminal V1-of the Hall element A and the input negative terminal V2-of the Hall element B; the No. 1 pin of the U3A and the No. 1 pin of the U4A are respectively connected with the power supply positive terminal V1+ of the Hall element A and the power supply positive terminal V2+ of the Hall element B. Therefore, after the pins 1,2 and 3 of the U3A and U4A are connected into the circuit, the 12V direct current power supply provides input voltage for the Hall element A and the Hall element B.

In the other branch after voltage division by TL-431, 2.5V voltage completes generation of 0.1V voltage-raising voltage through U4B. U4B acts as an emitter follower, creating a small voltage of 0.1V to complete the generation of a voltage to ground of 0.1V. The voltage of 2.5V is firstly connected to pin 5 of U4B through resistor R32 with resistance value of 24K Ω, and is grounded through resistor R33 with resistance value of 1K, voltage division is performed through two resistors R32 and R33, voltage of pin 5 is 0.1V, and when the linear working is performed, pin 6 of U4B is connected with pin 7 of output, and voltage of ground raising is 0.1V.

No. 5, 6 and 7 pins of U1A, U1B, U2A and U2B are connected to an amplifying circuit to amplify the voltage signal. The amplifying circuit is in a positive and negative two-way structure, and the structure of the positive and negative two-way circuit is not different, and the difference is that the voltage of the output pins U + and U-of the Hall element is high and low. If U + is larger than U-, the direction is positive, otherwise, the direction is reverse.

The No. 2 pin and the No. 3 pin of the U1A are respectively connected with an output positive terminal U1+ and an output negative terminal U1-of the Hall element A through a 1K omega resistor R8 and a 1K omega resistor R10; the resistor R6 is connected between the No. 1 pin and the No. 2 pin of the U1A, and the resistance value is 3K. A resistor R11 is connected between the No. 3 pin of the positive polarity end U1A and the No. 7 pin of U4B of the amplifying circuit, the resistance value is 3K, and the ground-raising voltage of 0.1V (the voltage of the No. 7 pin of U4B) is introduced into the amplifying circuit. The output end is connected with a resistor R9 with the resistance value of 1K omega, so that the short circuit caused by the misconnection of the load is prevented.

The No. 2 pin and the No. 3 pin of the U2A are respectively connected with the output positive terminal U2+ and the output negative terminal U2-of the Hall element B through a 1K omega resistor R21 and a 1K omega resistor R23. The resistor R20 is connected between the No. 1 pin and the No. 2 pin of the U2A, and the resistance value is 3K. A resistor R24 is connected between the No. 3 pin of the positive polarity end U2A and the No. 7 pin of the U4B of the amplifying circuit, the resistance value is 3K, and the ground-raising voltage of 0.1V (the voltage of the No. 7 pin of the U4B) is introduced into the amplifying circuit. The output end is connected with a resistor R22 with the resistance value of 1K omega, so that the short circuit caused by the misconnection of the load is prevented.

U1B is connected with the positive output end U1+ of the Hall element A through a No. 6 pin, and a 1K resistor R14 is connected between the U1B and the positive output end U1+ of the Hall element A; A3K resistor R13 is connected between the No. 6 pin and the No. 7 pin, the No. 5 pin is connected with the output negative terminal U1-of the Hall element A, and a 1K resistor R16 is connected between the No. 6 pin and the No. 7 pin. The No. 5 pin of the positive polarity end U1B of the amplifying circuit is connected with a ground-lifting voltage, a 3K resistor R17 is connected between the No. 7 pin of U4B, and the ground-lifting voltage of 0.1V (the voltage of the No. 7 pin of U4B) is introduced into the amplifying circuit to complete the amplifying function; the output end of the amplifying circuit is connected with a resistor R15 with the resistance value of 1K omega, so that the short circuit caused by the misconnection of the load is prevented.

U2B is connected with the positive output end U1+ of the Hall element B through a No. 6 pin, and a 1K resistor R28 is connected between the U2B and the positive output end U1+ of the Hall element B; A3K resistor R27 is connected between the No. 6 pin and the No. 7 pin, the No. 5 pin is connected with the output negative terminal U1-of the Hall element B, and a 1K resistor R30 is connected between the No. 6 pin and the No. 7 pin. The No. 5 pin of the positive polarity end U2B of the amplifying circuit is connected with a ground-lifting voltage, a 3K resistor R31 is connected between the No. 7 pin of U4B, and the ground-lifting voltage of 0.1V (the voltage of the No. 7 pin of U4B) is introduced into the amplifying circuit to complete the amplifying function; the output end of the amplifying circuit is connected with a resistor R29 with the resistance value of 1K omega, so that the short circuit caused by the misconnection of the load is prevented.

Through the design, the voltage value of the 2 pins of the two proportional amplifying circuits, namely R11, R17, R24 and R31, which belong to each Hall element is raised to 0.1V, so that the operational amplifier works in a linear region rather than a saturation region to improve the dynamic response of the circuit.

In the invention, the amplification factor of the amplifier circuit is 3 times, and then the resistances of the connected resistors R6, R11, R13, R17, R20, R24, R27 and R31 are the same as 3K omega, and the resistances of the resistors R8, R10, R14, R16, R21, R23, R28 and R30 are three times of the resistances of the resistors 1K omega, so as to ensure that the amplification factor in the amplifier circuit is three times, but not limited to 3 times. Therefore, the magnetic field signal induced by the Hall element is converted into a weak electric signal to be amplified to obtain a measurable voltage signal, so that the function of measuring the current of the contactor is achieved. If the magnification is to be changed, the resistances R6, R11, R13, R17, R20, R24, R27, and R31 are n times of R8, R10, R14, R16, R21, R23, R28, and R30, the magnification is n times, and the resistances of R8 and R10 are preferably in the K Ω level. However, in order to achieve the purpose of the dual hall element of the present invention to cancel the external magnetic field interference, it is necessary to ensure that the amplification factors of the four amplifying circuits are the same. The amplifier circuit in which U1A is located is illustrated as follows: when the magnification is 3 times, R8 is equal to R10, and R6 is equal to R11, the relationship (i) may be maintained and changed if the magnification is changed, and the magnification is n times if R6 is equal to R11 and n × R8 is equal to n × R10.

The invention is also provided with a temperature acquisition circuit, and a system temperature drift formed by a software compensation constant current source circuit, a Hall element and the like. The temperature acquisition circuit is composed of a 1K resistor R12 and a platinum resistor PT1000 which are connected in series and then grounded, and after the 12V direct-current power supply voltage is stabilized by a TL431 chip, the left end of a 1K resistor R12 is 2.5V. A voltage output end is led out from the connection part of the R12 and the platinum resistor, the right end of the platinum resistor is grounded, when the temperature of the experimental environment changes, the resistance value of the platinum resistor changes, the voltage division change of the platinum resistor in the temperature acquisition circuit is caused, the resistance value of the platinum resistor can be reversely pushed out through acquisition output, and the experimental environment temperature can be reversely pushed out according to the relation that the platinum resistor changes along with the temperature.

The invention relates to a double-Hall sensor conditioning circuit capable of detecting bidirectional current, which adopts double Hall elements to detect forward and reverse currents, each Hall element respectively outputs positive and negative two signals to reflect the magnitude of the detected current, 2 groups of signals and 4 signals are counted, when the positive current is introduced, the positive polarity potential of each Hall element is higher than the negative polarity potential, each Hall element is connected with two independent positive and negative current detection proportional amplifying circuits, and the amplification factor is three times, namely, the output of the forward current detection circuit is amplified by three times by the voltage difference of the output of the Hall element by the operational amplifier, and slightly higher than three times of voltage difference under the influence of zero bias, the output of the negative detection current circuit is supplied by a single power supply, the output of the negative detection current circuit is clamped at 0V by an operational amplifier and is influenced by zero bias (the output voltage value of the No. 7 pin of U4B) and is finally slightly higher than 0V, and the output of the negative detection current circuit is amplified by three times unlike the positive detection current circuit. When a negative current is applied, the process is reversed. The magnitude and direction of the current are detected based on the magnitudes of the 4 outputs. The invention respectively induces four groups of positive and negative voltage signals by using the double Hall elements which are symmetrically distributed on the PCB, each two positive signals are superposed, each two negative signals are superposed, the interference of an un-centered magnetic field can be eliminated, and the invention can also play a role of redundancy backup when one Hall element is damaged.