Circuit structure for outputting 4-20mA current based on single power supply

Abstract

The utility model relates to a circuit structure for outputting 4-20mA current based on single power supply. The circuit structure comprises a voltage division module, a first constant current module and a power supply module, the power supply module is used for providing voltage with a first amplitude and a second amplitude to supply power, the first amplitude is close to the second amplitude, and the first amplitude is greater than the second amplitude; the voltage division module is used for sampling the voltage detected by the Hall element and outputting a voltage sampling signal; and the first constant current module is connected with the voltage division module and is used for converting the voltage reflected by the voltage sampling signal into a current signal when receiving the voltage sampling signal, and the range of the magnitude of the current reflected by the current signal is 4-20 mA. According to the application, the voltage dividing module, the first constant current module and the power supply module are utilized to output 4-20mA current in a single power supply mode, so that the mentioned requirements of the Hall sensor are met.

Description

Technical Field

[0001] The present application relates to the field of Hall sensors, and in particular to a circuit structure that outputs 4-20 mA current based on a single power supply. Background Art

[0002] The Hall sensor is a magnetic field sensor made based on the Hall effect and can be used to detect current and voltage.

[0003] In the related art, the Hall sensor includes a detection circuit and an amplifier circuit with a Hall device. The detection circuit is used to collect the Hall voltage of the Hall device. The amplifier circuit is used to amplify the Hall voltage, convert it into a corresponding current signal and output it. The current value reflected by the current signal is generally in the range of 4mA~20mA.

[0004] Currently, due to the volume requirements of the Hall sensor, a demand is proposed to output 4~20mA current by powering with a single power supply. Utility Model Content

[0005] In order to achieve 4~20mA current output from a single power supply, the present application provides a circuit structure based on a single power supply to output 4~20mA current.

[0006] The present application provides a circuit structure based on a single power supply to output 4~20mA current, which adopts the following technical solution:

[0007] A circuit structure based on a single power supply and outputting a 4-20 mA current, comprising a voltage divider module, a first constant current module and a power supply module;

[0008] The power supply module is used to provide voltages of a first amplitude and a second amplitude for power supply, the first amplitude is close to the second amplitude, and the first amplitude is greater than the second amplitude;

[0009] The voltage divider module is used to sample the voltage detected by the Hall element and output a voltage sampling signal;

[0010] The first constant current module is connected to the voltage dividing module and is used to convert the voltage reflected by the voltage sampling signal into a current signal when receiving the voltage sampling signal. The current reflected by the current signal is in the range of 4-20 mA.

[0011] Optionally, a second constant current module is further included, wherein the second constant current module is connected to the first constant current module and the power supply module respectively, and is used to amplify the driving capability of the first constant current module.

[0012] Optionally, the voltage dividing module includes a first resistor, a second resistor, a third resistor, a fourth resistor and a sliding resistor;

[0013] One end of the first resistor is used to connect the voltage detected by the Hall device, and the other end is connected to the third resistor. The free end of the third resistor is grounded. The second resistor is connected in parallel with the first resistor, and the fourth resistor is connected in parallel with the third resistor. One end of the sliding variable resistor is used to connect the voltage detected by the Hall device, and the other end is grounded.

[0014] Optionally, the first constant current module includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first diode, a second diode, a third diode, a fourth diode, a first op amp, a first switch tube, a first capacitor and a first compensation unit;

[0015] The first op amp is connected to the power supply module to access the voltage of the first amplitude, the non-inverting input terminal of the first op amp is connected to the common terminal of the first resistor and the third resistor, and is connected to the sliding terminal of the sliding rheostat, the cathode of the first diode and the anode of the second diode are respectively connected to the non-inverting input terminal of the first op amp, the anode of the first diode and the cathode of the second diode are respectively connected to the inverting input terminal of the first op amp, the first compensation unit is connected to the output terminal of the first op amp, the control terminal of the first switch tube is connected to the first compensation unit, the input terminal of the first switch tube is connected to the power supply module through the fifth resistor and the first capacitor connected in series, and is connected to the inverting input terminal of the first op amp, the sixth resistor is connected in parallel with the fifth resistor, the output terminal of the first switch tube is connected to the power supply module through the seventh resistor and the eighth resistor connected in series to access the voltage of the second amplitude, the ninth resistor is connected in parallel with the eighth resistor, and the first compensation unit is used to compensate for the error voltage generated by the first op amp when the voltage detected by the Hall element is zero.

[0016] Optionally, the first compensation unit includes a third diode and a fourth diode;

[0017] The anode of the third diode is connected to the output end of the first operational amplifier, the anode of the fourth diode is connected to the cathode of the third diode, and the cathode of the fourth diode is connected to the control end of the first switch tube.

[0018] Optionally, the second constant current module includes a fifth diode, a sixth diode, a second operational amplifier, a second compensation unit, a second switch tube, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor and a fourteenth resistor;

[0019] The non-inverting input terminal of the second operational amplifier is connected to the common terminal of the seventh resistor and the eighth resistor, and is respectively connected to the anode of the fifth diode and the cathode of the sixth diode, the cathode of the fifth diode and the anode of the sixth diode are respectively connected to the inverting input terminal of the second operational amplifier, the second compensation unit is connected to the output terminal of the second operational amplifier, the control terminal of the second switch tube is connected to the second compensation unit, the input terminal of the second switch tube is connected to the inverting input terminal of the second operational amplifier, the output terminal of the second switch tube is connected to the fourteenth resistor, one end of the tenth resistor, one end of the eleventh resistor, one end of the twelfth resistor and one end of the thirteenth resistor are respectively connected to the input terminal of the second switch tube, the other end of the tenth resistor, the other end of the eleventh resistor, the other end of the twelfth resistor and the other end of the thirteenth resistor are respectively connected to the power supply module to access a voltage of a second amplitude, and the second compensation unit is used to compensate for the error voltage generated by the second operational amplifier when the voltage detected by the Hall element is zero.

[0020] Optionally, the second compensation unit includes a seventh diode and an eighth diode;

[0021] The cathode of the seventh diode is connected to the output end of the second operational amplifier, the cathode of the eighth diode is connected to the anode of the seventh diode, and the control end of the second switch tube is connected to the anode of the eighth diode.

[0022] Optionally, the power supply module includes a power supply unit, a ninth diode and a tenth diode;

[0023] The power supply unit is used to provide a voltage of a first amplitude;

[0024] An anode of the ninth diode is connected to the power supply unit, an anode of the tenth diode is connected to a cathode of the ninth diode, and a cathode of the tenth diode outputs a voltage of a second amplitude.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] The present application utilizes a voltage divider module, a first constant current module and a power supply module to output a 4-20 mA current through a single power supply to meet the requirements for the Hall sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a circuit diagram of a circuit structure of an embodiment of the present application that outputs 4-20mA current based on a single power supply.

[0028] Explanation of the accompanying drawings: 1. power supply module; 2. voltage divider module; 3. first constant current module; 4. second constant current module; 5. first compensation unit; 6. second compensation unit. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of this application more clear, the following Figure 1 It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0030] The present application embodiment discloses a circuit structure that outputs 4-20 mA current based on a single power supply. Figure 1 The circuit structure for outputting 4~20mA current based on single power supply includes a power supply module 1, a voltage divider module 2, a first constant current module 3 and a second constant current module 4, so as to output 4~20mA current by single power supply to meet the requirements of the Hall sensor.

[0031] The power supply module 1 is used to provide voltages of a first amplitude and a second amplitude for power supply. The first amplitude is close to the second amplitude, and the first amplitude is greater than the second amplitude. The power supply module 1 includes a power supply unit, a ninth diode and a tenth diode.

[0032] Specifically, the power supply unit is used to provide a voltage of a first amplitude. The anode of the ninth diode is connected to the power supply unit, the anode of the tenth diode is connected to the cathode of the ninth diode, and the cathode of the tenth diode outputs a voltage of a second amplitude. In the embodiment of the present application, the first amplitude is 12V and the second amplitude is 10.6V.

[0033] The voltage dividing module 2 is used to sample the voltage detected by the Hall element and output a voltage sampling signal. The voltage dividing module 2 includes a first resistor R17, a second resistor R18, a third resistor R24, a fourth resistor R25 and a sliding variable resistor OFS2.

[0034] Specifically, one end of the first resistor R17 is used to connect the voltage detected by the Hall device, and the other end is connected to the third resistor R24, the free end of the third resistor R24 ​​is grounded, the second resistor R18 is connected in parallel with the first resistor R17, the fourth resistor R25 is connected in parallel with the third resistor R24, one end of the sliding variable resistor OFS2 is used to connect the voltage detected by the Hall device, and the other end is grounded, and its sliding end is connected to the common end of the first resistor R17 and the third resistor R24. The common end of the first resistor R17 and the third resistor R24 ​​is used as an output end to output a voltage sampling signal.

[0035] The first constant current module 3 is connected to the voltage dividing module 2, and is used to receive the voltage sampling signal. When receiving the voltage sampling signal, the voltage reflected by the voltage sampling signal is converted into a current signal, and the current reflected by the current signal ranges from 4 to 20 mA. The first constant current module 3 includes a fifth resistor R26, a sixth resistor R23, a seventh resistor R15, an eighth resistor R16, a ninth resistor R13, a tenth resistor R19, a first diode D17, a second diode D7, a third diode D15, a fourth diode D5, a first op amp IC2B, a first switch tube BG1, a first capacitor C6, and a first compensation unit 5.

[0036] Specifically, the first op amp IC2B is connected to the power supply module 1 to access the voltage of the first amplitude, the non-inverting input terminal of the first op amp IC2B is connected to the common terminal of the first resistor R17 and the third resistor R24, and is connected to the sliding terminal of the sliding variable resistor OFS2, the cathode of the first diode D17 and the anode of the second diode D7 are respectively connected to the non-inverting input terminal of the first op amp IC2B, the anode of the first diode D17 and the cathode of the second diode D7 are respectively connected to the inverting input terminal of the first op amp IC2B, and the first compensation unit 5 is connected to the first op amp IC2B. The output end of the amplifier IC2B, the control end of the first switch tube BG1 is connected to the first compensation unit 5, the input end of the first switch tube BG1 is connected to the power supply module 1 through the fifth resistor R26 and the first capacitor C6 connected in series, and is connected to the inverting input end of the first op amp IC2B, the sixth resistor R23 is connected in parallel with the fifth resistor R26, the output end of the first switch tube BG1 is connected to the power supply module 1 through the seventh resistor R15 and the eighth resistor R16 connected in series to access the voltage of the second amplitude, and the ninth resistor R13 is connected in parallel with the eighth resistor R16. In the embodiment of the present application, the first switch tube BG1 is an NPN transistor. Of course, in other embodiments, the model of the first switch tube BG1 can also be selected according to the control logic of the circuit.

[0037] The first compensation unit 5 is used to compensate the error voltage generated by the first op amp IC2B when the voltage detected by the Hall element is zero. The first compensation unit 5 includes a third diode D15 and a fourth diode D5. Specifically, the anode of the third diode D15 is connected to the output end of the first op amp IC2B, the anode of the fourth diode D5 is connected to the cathode of the third diode D15, and the cathode of the fourth diode D5 is connected to the control end of the first switch tube BG1.

[0038] The second constant current module 4 is connected to the first constant current module 3 and the power supply module 1 respectively, and is used to amplify the driving ability of the first constant current module 3. The second constant current module 4 includes a fifth diode D14, a sixth diode D4, a second op amp IC2A, a second compensation unit 6, a second switch tube BG2, a tenth resistor R19, an eleventh resistor R20, a twelfth resistor R21, a thirteenth resistor R22 and a fourteenth resistor R14.

[0039] Specifically, the non-inverting input terminal of the second operational amplifier IC2A is connected to the common terminal of the seventh resistor R15 and the eighth resistor R16, and is respectively connected to the anode of the fifth diode D14 and the cathode of the sixth diode D4, the cathode of the fifth diode D14 and the anode of the sixth diode D4 are respectively connected to the inverting input terminal of the second operational amplifier IC2A, the second compensation unit 6 is connected to the output terminal of the second operational amplifier IC2A, the control terminal of the second switch tube BG2 is connected to the second compensation unit 6, and the input terminal of the second switch tube BG2 is connected to the second operational amplifier IC2A. The inverting input terminal of the amplifier IC2A, the output terminal of the second switch tube BG2 is connected to the fourteenth resistor R14, one end of the tenth resistor R19, one end of the eleventh resistor R20, one end of the twelfth resistor R21 and one end of the thirteenth resistor R22 are respectively connected to the input terminal of the second switch tube BG2, and the other end of the tenth resistor R19, the other end of the eleventh resistor R20, the other end of the twelfth resistor R21 and the other end of the thirteenth resistor R22 are respectively connected to the power supply module 1 to access the voltage of the second amplitude. In the embodiment of the present application, the second switch tube BG2 is a PNP type triode. Of course, in other embodiments, the model of the first switch tube BG1 can also be selected according to the control logic of the circuit.

[0040] The second compensation unit 6 is used to compensate the error voltage generated by the second amplifier IC2A when the voltage detected by the Hall element is zero. The second compensation unit 6 includes a seventh diode D16 and an eighth diode D6. Specifically, the cathode of the seventh diode D16 is connected to the output end of the second amplifier IC2A, the cathode of the eighth diode D6 is connected to the anode of the seventh diode D16, and the control end of the second switch tube BG2 is connected to the anode of the eighth diode D6.

[0041] Of course, in some other embodiments, it is also possible not to add the second constant current module 4.

[0042] The implementation principle of a circuit structure based on a single power supply to output 4~20mA current in an embodiment of the present application is: using a voltage divider module 2, a first constant current module 3 and a power supply module 1 to output 4~20mA current through a single power supply to meet the requirements mentioned for the Hall sensor.

[0043] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any feature disclosed in this specification (including the abstract and drawings), unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

Claims

1. A circuit structure based on a single power supply outputting 4~20mA current, characterized in that: It comprises a voltage dividing module (2), a first constant current module (3) and a power supply module (1); The power supply module (1) is used to provide voltages of a first amplitude and a second amplitude for power supply, the first amplitude is close to the second amplitude, and the first amplitude is greater than the second amplitude; The voltage dividing module (2) is used to sample the voltage detected by the Hall element and output a voltage sampling signal; The first constant current module (3) is connected to the voltage dividing module (2) and is used for converting the voltage reflected by the voltage sampling signal into a current signal when receiving the voltage sampling signal, wherein the current reflected by the current signal has a magnitude ranging from 4 to 20 mA.

2. The circuit structure of outputting 4-20 mA current based on a single power supply according to claim 1, characterized in that: It also comprises a second constant current module (4), wherein the second constant current module (4) is respectively connected to the first constant current module (3) and the power supply module (1) and is used to amplify the driving capability of the first constant current module (3).

3. The circuit structure of outputting 4-20 mA current based on a single power supply according to claim 2, characterized in that: The voltage dividing module (2) comprises a first resistor, a second resistor, a third resistor, a fourth resistor and a sliding resistor; One end of the first resistor is used to connect the voltage detected by the Hall device, and the other end is connected to the third resistor. The free end of the third resistor is grounded. The second resistor is connected in parallel with the first resistor, and the fourth resistor is connected in parallel with the third resistor. One end of the sliding variable resistor is used to connect the voltage detected by the Hall device, and the other end is grounded.

4. The circuit structure of outputting 4-20 mA current based on a single power supply according to claim 3, characterized in that: The first constant current module (3) comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first diode, a second diode, a third diode, a fourth diode, a first operational amplifier, a first switch tube, a first capacitor and a first compensation unit (5); The first operational amplifier is connected to the power supply module (1) to receive the voltage of the first amplitude; the non-inverting input terminal of the first operational amplifier is connected to the common terminal of the first resistor and the third resistor, and is connected to the sliding terminal of the sliding variable resistor; the cathode of the first diode and the anode of the second diode are respectively connected to the non-inverting input terminal of the first operational amplifier; the anode of the first diode and the cathode of the second diode are respectively connected to the inverting input terminal of the first operational amplifier; the first compensation unit (5) is connected to the output terminal of the first operational amplifier; the control terminal of the first switching tube is connected to the first compensation unit (5); the input terminal of the first switching tube is connected to the power supply module (1) through the fifth resistor and the first capacitor connected in series, and is connected to the inverting input terminal of the first operational amplifier; the sixth resistor is connected in parallel with the fifth resistor; the output terminal of the first switching tube is connected to the power supply module (1) through the seventh resistor and the eighth resistor connected in series to receive the voltage of the second amplitude; the ninth resistor is connected in parallel with the eighth resistor; the first compensation unit (5) is used to compensate for the error voltage generated by the first operational amplifier when the voltage detected by the Hall element is zero.

5. The circuit structure of outputting 4-20 mA current based on a single power supply according to claim 4, characterized in that: The first compensation unit (5) comprises a third diode and a fourth diode; The anode of the third diode is connected to the output end of the first operational amplifier, the anode of the fourth diode is connected to the cathode of the third diode, and the cathode of the fourth diode is connected to the control end of the first switch tube.

6. The circuit structure of outputting 4-20 mA current based on a single power supply according to claim 4, characterized in that: The second constant current module (4) comprises a fifth diode, a sixth diode, a second operational amplifier, a second compensation unit (6), a second switch tube, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor and a fourteenth resistor; The non-inverting input terminal of the second operational amplifier is connected to the common terminal of the seventh resistor and the eighth resistor, and is respectively connected to the anode of the fifth diode and the cathode of the sixth diode. The cathode of the fifth diode and the anode of the sixth diode are respectively connected to the inverting input terminal of the second operational amplifier. The second compensation unit (6) is connected to the output terminal of the second operational amplifier. The control terminal of the second switch tube is connected to the second compensation unit (6). The input terminal of the second switch tube is connected to the inverting input terminal of the second operational amplifier. The output terminal of the second switch tube is connected to the fourteenth resistor. One end of the tenth resistor, one end of the eleventh resistor, one end of the twelfth resistor and one end of the thirteenth resistor are respectively connected to the input terminal of the second switch tube. The other end of the tenth resistor, the other end of the eleventh resistor, the other end of the twelfth resistor and the other end of the thirteenth resistor are respectively connected to the power supply module (1) to access a voltage of a second amplitude. The second compensation unit (6) is used to compensate for the error voltage generated by the second operational amplifier when the voltage detected by the Hall element is zero.

7. The circuit structure of outputting 4-20 mA current based on a single power supply according to claim 6, characterized in that: The second compensation unit (6) comprises a seventh diode and an eighth diode; The cathode of the seventh diode is connected to the output end of the second operational amplifier, the cathode of the eighth diode is connected to the anode of the seventh diode, and the control end of the second switch tube is connected to the anode of the eighth diode.

8. The circuit structure of outputting 4-20 mA current based on a single power supply according to claim 7, characterized in that: The power supply module (1) comprises a power supply unit, a ninth diode and a tenth diode; The power supply unit is used to provide a voltage of a first amplitude; An anode of the ninth diode is connected to the power supply unit, an anode of the tenth diode is connected to a cathode of the ninth diode, and a cathode of the tenth diode outputs a voltage of a second amplitude.

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