Measuring circuit for current source, high-stability bidirectional current source and working method of high-stability bidirectional current source

Abstract

The invention belongs to the technical field of measurement, and particularly relates to a measuring circuit for a current source, a high-stability bidirectional current source and a working method of the high-stability bidirectional current source, and the measuring circuit for the current source comprises a current source output module, an isolation switch module and a current measuring module. When the isolating switch module is conducted, the current source output module outputs forward or reverse controllable current, and the current measurement module detects the output current to correct the output current; when the isolation switch module is cut off, insulation isolation is provided. Controllable output of forward current and reverse current can be achieved, the isolation switch module provides high-insulation isolation when the current source output module does not output, low electric leakage and reliable live switching capacity are achieved, the stability of the circuit in the switching-on and switching-off process is guaranteed, and the reliability of the circuit is improved. And the current measurement module can accurately measure the output current in real time so as to correct the output, so that the problems of large leakage current interference, poor circuit stability and insufficient measurement precision in the existing current source can be effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology, specifically relating to devices for measuring current, and more particularly to a current source measurement circuit, a highly stable bidirectional current source, and its operating method. Background Technology

[0002] The current source is used in precision source meters to output a stable current and measure the current simultaneously.

[0003] Existing current sources have the following problems: insufficient output current accuracy, easily affected by noise and leakage current interference when outputting weak current or bidirectional current; transient disturbances are easily generated during switching, resulting in unstable output; and the measurement feedback adjustment accuracy is limited, making it difficult to achieve high-precision adjustable output.

[0004] Therefore, there is an urgent need to develop a new measurement circuit for current sources, a highly stable bidirectional current source and its operating method to solve the technical problems of poor output current accuracy, instability and low measurement feedback adjustment accuracy of existing current sources.

[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention

[0006] This disclosure provides at least one measurement circuit for a current source, a highly stable bidirectional current source, and a method for operating the same.

[0007] In a first aspect, embodiments of this disclosure provide a measurement circuit for a current source, comprising: a current source output module, an isolating switch module, and a current measurement module; wherein the isolating switch module and the current measurement module are electrically connected to the current source output module; when the isolating switch module is turned on, the current source output module outputs a forward controllable current or a reverse controllable current to the current output terminal through the isolating switch module, and the current measurement module detects the forward controllable current or the reverse controllable current output by the current source output module, so that the current source output module corrects the output forward controllable current or the reverse controllable current; when the isolating switch module is turned off, the isolating switch module isolates the current source output module from the current output terminal.

[0008] In one optional embodiment, the current source output module includes a microprocessor and a controllable voltage source; the controllable voltage source and the current measurement module are electrically connected to the microprocessor, the controllable voltage source is electrically connected to the isolating switch module, and the current measurement module is electrically connected to the controllable voltage source; the microprocessor drives the controllable voltage source to output a forward controllable current or a reverse controllable current to the current output terminal via the isolating switch module; the current measurement module detects the forward controllable current or the reverse controllable current output by the controllable voltage source and feeds back the detection signal to the microprocessor; the microprocessor corrects the forward controllable current or the reverse controllable current output by the controllable voltage source according to the detection signal.

[0009] In one optional embodiment, the disconnecting switch module includes: a first reed relay, a first field-effect transistor (FET), a second FET, a third FET, and a first diode; a first terminal of the first reed relay is electrically connected to a current output terminal, a second terminal of the first reed relay is electrically connected to a power supply and to the cathode of the first diode, a third terminal of the first reed relay is electrically connected to the anode of the first diode and the drain of the first FET, and a fourth terminal of the first reed relay is electrically connected to the drain of the second FET; the source of the first FET is grounded, the gate of the first FET is electrically connected to a first control signal terminal, the source of the second FET is electrically connected to the source of the third FET, and the gates of the second and third FETs are electrically connected to a second control signal terminal.

[0010] In one optional implementation, the first field-effect transistor is turned on or off under the control of the first control signal terminal to control the first reed relay to close or open; when the first reed relay is closed, the second and third field-effect transistors are turned on synchronously under the control of the second control signal terminal so that the controllable voltage source outputs a positive controllable current or a reverse controllable current to the current output terminal.

[0011] In one optional embodiment, the current measurement module includes: a sampling resistor unit, a buffer unit, a first analog switch unit, a second analog switch unit, a third analog switch unit, a fourth field-effect transistor (FET), a fifth FET, a sixth FET, a seventh FET, and a signal conditioning unit; the input terminal of the buffer unit and the drain of the third FET are electrically connected to the sampling resistor unit, and the sampling resistor unit is electrically connected to the signal conditioning unit; the output terminal of the buffer unit is electrically connected to the first analog switch unit, and the drains of the first analog switch unit, the second analog switch, the fourth FET, and the source of the fifth FET are electrically connected to the same connection point, and the sampling resistor unit is electrically connected to the signal conditioning unit. An analog switch unit, a second analog switch unit, and a third control signal terminal are electrically connected; the drain of the fifth field-effect transistor is electrically connected to the source of the sixth field-effect transistor; the gates of the fourth, fifth, sixth, and seventh field-effect transistors are electrically connected to the fourth control signal terminal; the sources of the fourth and seventh field-effect transistors are electrically connected to a sampling resistor unit; the drain of the seventh field-effect transistor, the second analog switch unit, and the third analog switch unit are connected to the same connection point; the third analog switch unit is electrically connected to the fifth control signal terminal and is also electrically connected to a signal conditioning unit.

[0012] In one optional implementation, the signal conditioning unit includes a voltage follower circuit, a proportional amplifier circuit, and a differential circuit. The voltage follower circuit and the proportional amplifier circuit are electrically connected to the third analog switch unit and the sampling resistor unit, respectively, to obtain the sampled voltage, amplify it, and transmit it to the differential circuit to process common-mode interference until the sampled voltage is output to the microprocessor to convert it into the current measurement current.

[0013] In one optional implementation, the first analog switch unit and the second analog switch unit are synchronously disconnected under the control of the third control signal terminal, the third analog switch unit is closed under the control of the fifth control signal terminal, and the fourth, fifth, sixth, and seventh field-effect transistors are synchronously turned on under the control of the fourth control signal terminal, so that the voltage follower circuit and the proportional amplifier circuit can collect the forward controllable current or reverse controllable current output by the controllable voltage source through the sampling resistor unit.

[0014] In one optional implementation, the first analog switch unit and the second analog switch unit are synchronously closed under the control of the third control signal terminal, the third analog switch unit is opened under the control of the fifth control signal terminal, the fourth field-effect transistor, the fifth field-effect transistor, the sixth field-effect transistor, and the seventh field-effect transistor are synchronously turned off under the control of the fourth control signal terminal, and the buffer unit keeps the two sides of the sampling resistor unit at the same potential.

[0015] Secondly, embodiments of this disclosure also provide a highly stable bidirectional current source, which includes: a current source measurement circuit as described above.

[0016] Thirdly, this disclosure also provides a method for operating a current source measurement circuit as described above, comprising: when the isolating switch module is turned on, the current source output module outputs a forward controllable current or a reverse controllable current to the current output terminal through the isolating switch module, and the current measurement module detects the forward controllable current or the reverse controllable current output by the current source output module so as to correct the output forward controllable current or the reverse controllable current; when the isolating switch module is turned off, the isolating switch module isolates the current source output module from the current output terminal.

[0017] The beneficial effects of this invention are that, through the cooperation of the current source output module and the isolating switch module, it can achieve controllable output of forward and reverse current. At the same time, the isolating switch module provides high insulation isolation when the current source output module is not outputting, and has low leakage current and reliable on-line switching capability to ensure the stability of the circuit during the turn-on and turn-off process. Furthermore, the current measurement module can accurately measure the output current in real time and feed it back to the current source output module to correct the output. This effectively overcomes the problems of large leakage current interference, poor circuit stability and insufficient measurement accuracy in existing current sources.

[0018] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A schematic block diagram of a current source measurement circuit provided in an embodiment of this disclosure;

[0022] Figure 2 A circuit diagram of a current source measurement circuit provided for an embodiment of this disclosure;

[0023] Figure 3 A circuit diagram of an optional implementation of a current measurement module provided in this disclosure.

[0024] In the picture:

[0025] MCU, Microprocessor; VCC1, Controllable Voltage Source; K1, First Reed Relay;

[0026] Q1, First field-effect transistor; Q2, Second field-effect transistor; Q3, Third field-effect transistor; Q4, Fourth field-effect transistor; Q5, Fifth field-effect transistor; Q6, Sixth field-effect transistor; Q7, Seventh field-effect transistor;

[0027] D1, first diode; Buffer, buffer unit.

[0028] I out Current output terminal;

[0029] Control1, first control signal terminal; Control2, second control signal terminal; Control3, third control signal terminal; Control4, fourth control signal terminal; Control5, fifth control signal terminal. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0032] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0033] Research has revealed that current sources are used in precision current meters to output stable current and simultaneously measure current. Existing current sources suffer from the following problems: insufficient output current accuracy, susceptibility to noise and leakage current interference when outputting weak or bidirectional currents; transient disturbances during switching, leading to unstable output; and limited measurement feedback adjustment accuracy, making it difficult to achieve high-precision adjustable output.

[0034] Based on the above research, this disclosure provides a current source measurement circuit, a high-stability bidirectional current source, and its operating method. By cooperating with the current source output module and the isolating switch module, controllable output of forward and reverse current can be achieved. At the same time, the isolating switch module provides high insulation isolation when the current source output module is not outputting, and has low leakage current and reliable on-line switching capability to ensure the stability of the circuit during the turn-on and turn-off process. Furthermore, the current measurement module can accurately measure the output current in real time and feed it back to the current source output module to correct the output. This effectively overcomes the problems of large leakage current interference, poor circuit stability, and insufficient measurement accuracy in existing current sources.

[0035] The shortcomings of the above solutions are the result of the inventor's practical experience and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure below should be considered as the inventor's contribution to this disclosure.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0037] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0038] like Figures 1 to 3As shown, at least one embodiment provides a current source measurement circuit, which includes: a current source output module, an isolating switch module, and a current measurement module; wherein the isolating switch module and the current measurement module are electrically connected to the current source output module; when the isolating switch module is turned on, the current source output module supplies current to the current output terminal I through the isolating switch module. out The system outputs a forward-controllable current or a reverse-controllable current, and the current measurement module detects the forward-controllable current or the reverse-controllable current output by the current source output module, so that the current source output module can correct the output forward-controllable current or the reverse-controllable current; when the isolating switch module is turned off, the isolating switch module connects the current source output module to the current output terminal I. out Insulation and isolation.

[0039] Specifically, the disconnect switch module provides high insulation isolation when the current source output module is not outputting, and has low leakage current and reliable live switching capability to ensure the stability of the circuit during the turn-on and turn-off process.

[0040] Specifically, the current source output module can adjust the output in real time based on the measurement results fed back by the current measurement module, so as to achieve controllable output of forward and reverse current.

[0041] Specifically, the current measurement module is used to accurately measure the output current and feed the measurement results back to the current source output module to correct the output.

[0042] In at least one embodiment, the controllable output of forward and reverse current can be achieved by the cooperation of the current source output module and the isolating switch module. At the same time, the isolating switch module provides high insulation isolation when the current source output module is not outputting, and has low leakage current and reliable on-line switching capability to ensure the stability of the circuit during the turn-on and turn-off process. Furthermore, the current measurement module can accurately measure the output current in real time and feed it back to the current source output module to correct the output. This can effectively overcome the problems of large leakage current interference, poor circuit stability and insufficient measurement accuracy in existing current sources.

[0043] In at least one embodiment, please refer to Figure 2 The current source output module includes a microprocessor (MCU) and a controllable voltage source VCC1. The controllable voltage source VCC1 and the current measurement module are electrically connected to the MCU. The controllable voltage source VCC1 is electrically connected to the isolating switch module, and the current measurement module is also electrically connected to the controllable voltage source VCC1. The MCU drives the controllable voltage source VCC1 to output current to the current output terminal I via the isolating switch module. outThe system outputs a forward controllable current or a reverse controllable current; the current measurement module detects the forward controllable current or the reverse controllable current output by the controllable voltage source VCC1, and feeds back the detection signal to the microprocessor MCU; the microprocessor MCU corrects the forward controllable current or the reverse controllable current output by the controllable voltage source VCC1 according to the detection signal.

[0044] In at least one embodiment, please refer to Figure 2 The disconnecting switch module includes: a first reed relay K1, a first field-effect transistor Q1, a second field-effect transistor Q2, a third field-effect transistor Q3, and a first diode D1; the first terminal of the first reed relay K1 is connected to the current output terminal I. out Electrically connected, the second terminal of the first reed relay K1 is electrically connected to the power supply and the cathode of the first diode D1; the third terminal of the first reed relay K1 is electrically connected to the anode of the first diode D1 and the drain of the first field-effect transistor Q1; the fourth terminal of the first reed relay K1 is electrically connected to the drain of the second field-effect transistor Q2; the source of the first field-effect transistor Q1 is grounded; the gate of the first field-effect transistor Q1 is electrically connected to the first control signal terminal Control1; the source of the second field-effect transistor Q2 is electrically connected to the source of the third field-effect transistor Q3; the gates of the second field-effect transistor Q2 and the gate of the third field-effect transistor Q3 are electrically connected to the second control signal terminal Control2.

[0045] In at least one embodiment, please refer to Figure 2 The first field-effect transistor Q1 is turned on or off under the control of the first control signal terminal Control1 to control the first reed relay K1 to close or open; when the first reed relay K1 is closed, the second field-effect transistor Q2 and the third field-effect transistor Q3 are synchronously turned on under the control of the second control signal terminal Control2, so that the controllable voltage source VCC1 supplies current to the current output terminal I. out It outputs a controllable current in the forward direction or a controllable current in the reverse direction.

[0046] Specifically, the first field-effect transistor Q1 is used to control the first reed relay K1 to close or open. When the first field-effect transistor Q1 is turned on, the third terminal of the first reed relay K1 is grounded through the first field-effect transistor Q1, thereby realizing the closure of the first reed relay K1.

[0047] Specifically, the second field-effect transistor Q2 and the third field-effect transistor Q3 are simultaneously turned on or off under the control of the second control signal terminal Control2. Due to the presence of the body diodes inside the second field-effect transistor Q2 and the third field-effect transistor Q3, when the current is in the forward output direction, the third field-effect transistor Q3 is active while the second field-effect transistor Q2 is inactive; when the circuit is in the reverse output direction, the second field-effect transistor Q2 is active while the third field-effect transistor Q3 is inactive. This enables the controllable voltage source VCC1 to output current to the current output terminal I. out It outputs a controllable current in the forward direction or a controllable current in the reverse direction.

[0048] In at least one embodiment, please refer to Figure 2 The current measurement module includes: a sampling resistor unit, a buffer unit, a first analog switch unit, a second analog switch unit, a third analog switch unit, a fourth field-effect transistor Q4, a fifth field-effect transistor Q5, a sixth field-effect transistor Q6, a seventh field-effect transistor Q7, and a signal conditioning unit. The input terminal of the buffer unit and the drain of the third field-effect transistor Q3 are electrically connected to the sampling resistor unit, and the sampling resistor unit is electrically connected to the signal conditioning unit. The output terminal of the buffer unit is electrically connected to the first analog switch unit. The first analog switch unit, the second analog switch, the drain of the fourth field-effect transistor Q4, and the source of the fifth field-effect transistor Q5 are electrically connected to the same connection point. The analog switch unit is electrically connected to the third control signal terminal Control3; the drain of the fifth field-effect transistor Q5 is electrically connected to the source of the sixth field-effect transistor Q6; the gates of the fourth field-effect transistor Q4, the fifth field-effect transistor Q5, the sixth field-effect transistor Q6, and the seventh field-effect transistor Q7 are electrically connected to the fourth control signal terminal Control4; the sources of the fourth field-effect transistor Q4 and the seventh field-effect transistor Q7 are electrically connected to the sampling resistor unit; the drain of the seventh field-effect transistor Q7, the second analog switch unit, and the third analog switch unit are connected to the same connection point; the third analog switch unit is electrically connected to the fifth control signal terminal Control5, and the third analog switch unit is electrically connected to the signal conditioning unit.

[0049] In at least one embodiment, please refer to Figure 2 The signal conditioning unit includes a voltage follower circuit, a proportional amplifier circuit, and a differential circuit. The voltage follower circuit and the proportional amplifier circuit are electrically connected to the third analog switch unit and the sampling resistor unit, respectively, to obtain the sampled voltage and amplify it before transmitting it to the differential circuit to process common-mode interference until the sampled voltage is output to the microprocessor MCU to convert it into the current measurement current.

[0050] Specifically, the voltage follower circuit consists of a first operational amplifier U1 and a first resistor R1, which is used to isolate the sampling point signal and reduce the driving impedance.

[0051] Specifically, the proportional amplifier circuit consists of a second operational amplifier U2, a second resistor R2, a third resistor R3, and a fourth resistor R4, and is used to amplify the sampled voltage.

[0052] Specifically, the differential circuit consists of a third operational amplifier U3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8, which are used to reduce common-mode interference and achieve high-precision measurement.

[0053] In at least one embodiment, please refer to Figure 2 The first and second analog switch units are synchronously disconnected under the control of the third control signal terminal Control3, and the third analog switch unit is closed under the control of the fifth control signal terminal Control5. The fourth field-effect transistor Q4, the fifth field-effect transistor Q5, the sixth field-effect transistor Q6, and the seventh field-effect transistor Q7 are synchronously turned on under the control of the fourth control signal terminal Control4, so that the voltage follower circuit and the proportional amplifier circuit can collect the forward or reverse controllable current output by the controllable voltage source VCC1 through the sampling resistor unit.

[0054] In at least one embodiment, please refer to Figure 2 The first analog switch unit and the second analog switch unit are closed synchronously under the control of the third control signal terminal Control3, the third analog switch unit is opened under the control of the fifth control signal terminal Control5, the fourth field-effect transistor Q4, the fifth field-effect transistor Q5, the sixth field-effect transistor Q6, and the seventh field-effect transistor Q7 are closed synchronously under the control of the fourth control signal terminal Control4, and the buffer unit keeps the two sides of the sampling resistor unit at the same potential.

[0055] Specifically, please refer to Figure 2 As an optional implementation of the current measurement module, the sampling resistor unit includes: a first sampling resistor R S1 The first analog switch unit includes: a first analog switch S1; the second analog switch unit includes: a second analog switch S2; the third analog switch unit includes: a third analog switch S3; the input terminal of the buffer unit, the drain of the third field-effect transistor Q3, and the first sampling resistor R. S1 One end is connected, and the connection point V is... LAs the first measurement input terminal of the signal conditioning unit, the output terminal of the buffer unit is connected to one end of the first analog switch S1. The other end of the first analog switch S1, one end of the second analog switch S2, the drain of the fourth field-effect transistor Q4, and the source of the fifth field-effect transistor Q5 are connected. The third control signal terminal Control3 simultaneously controls the first analog switch S1 and the second analog switch S2. The drain of the fifth field-effect transistor Q5 is connected to the source of the sixth field-effect transistor Q6. The gates of the fifth field-effect transistor Q5, the sixth field-effect transistor Q6, the fourth field-effect transistor Q4, and the seventh field-effect transistor Q7 are all connected to the fourth control signal terminal Control4. The sources of the fourth field-effect transistor Q4 and the seventh field-effect transistor Q7 are both connected to the first sampling resistor R. S1 The other end V H The drain of the seventh field-effect transistor Q7, the other end of the second analog switch S2, and one end of the third analog switch S3 are connected. The fifth control signal terminal Control5 controls the third analog switch S3, and the other end of the third analog switch S3 serves as the second measurement input terminal of the signal conditioning unit.

[0056] Specifically, when the current source output module is turned on, the first control signal terminal Control1 is first set to a high level, turning on the first field-effect transistor Q1, thereby driving the first reed relay K1 to close; then, after a delay of about 1ms, the second control signal terminal Control2 is set to a high level, driving the second field-effect transistor Q2 and the third field-effect transistor Q3 to conduct, thereby achieving stable start-up of the isolating switch module and ensuring the connection between the current source output module and the current output terminal I. out Connected.

[0057] Specifically, when the current source output module shuts down, the second control signal terminal Control2 is first set to a low level, turning off the second field-effect transistor Q2 and the third field-effect transistor Q3. After a delay of approximately 1ms, the first control signal terminal Control1 is then set to a low level, thereby turning off the first field-effect transistor Q1 and disconnecting the first reed relay K1, achieving a smooth turn-off process. This control timing effectively avoids shocks and instability during current source switching.

[0058] Specifically, when the output current of the current source output module flows through the first sampling resistor R S1 At this time, the third control signal terminal Control3 is set to a high level, causing the first analog switch S1 and the second analog switch S2 to disconnect; the fourth control signal terminal Control4 is set to a high level, causing the fourth field-effect transistor Q4, the fifth field-effect transistor Q5, the sixth field-effect transistor Q6, and the seventh field-effect transistor Q7 to conduct. At this time, the output of the controllable voltage source VCC1 passes sequentially through the sixth field-effect transistor Q6, the fifth field-effect transistor Q5, the fourth field-effect transistor Q4, and the first sampling resistor R. S1A stable, adjustable current source signal is output via the third field-effect transistor Q3, the second field-effect transistor Q2, and the first reed relay K1; simultaneously, the first sampling resistor R... S1 The potential at one end is taken as V L The voltage at the other end is input to the first measurement input terminal of the signal conditioning unit, and the voltage at the other end is input to the second measurement input terminal of the signal conditioning unit through the seventh field-effect transistor Q7 and the third analog switch S3 and recorded as V. H Because the signal conditioning unit has high input impedance characteristics, the on-resistance between the seventh field-effect transistor Q7 and the third analog switch mainly serves to provide V. H It provides output impedance.

[0059] Specifically, when the output current of the current source output module does not flow through the first sampling resistor R S1 At this time, the third control signal terminal Control3 is low, the fourth control signal terminal Control4 is low, and the fifth control signal terminal Control5 is high. Simultaneously, the first analog switch S1 and the second analog switch S2 are turned on, the third analog switch S3 is turned off, and the fourth field-effect transistor Q4, the fifth field-effect transistor Q5, the sixth field-effect transistor Q6, and the seventh field-effect transistor Q7 are all turned off. Therefore, the controllable voltage source VCC1 does not pass through the first sampling resistor R. S1 .

[0060] Specifically, the output current I out The current flows through the first sampling resistor R S1 V H -V L =I out ·R S1 The output voltage of the voltage follower circuit is: V1 = V H Output voltage of the proportional amplifier circuit: The output voltage of the differential circuit is: Where R5 = R6 = R7 = R8, then we have: Under the above conditions, the output voltage V of the microprocessor MCU acquisition signal conditioning unit OUT The current being measured is obtained through conversion.

[0061] Specifically, please refer to Figure 2 In the first sampling resistor R S1 When not in measurement mode, the first sampling resistor R is controlled by the buffer unit. S1 To avoid leakage current, the two ends are kept at the same potential, in the first sampling resistor R S1 When in measurement mode, the output voltage signal is sent to the signal conditioning unit.

[0062] Specifically, please refer to Figure 3As another optional implementation of the current measurement module, the sampling resistor unit includes: a first sampling resistor R S1 Second sampling resistor R S2 The third sampling resistor R S3 Fourth sampling resistor R S4 The first analog switch unit includes: switch S 1-1 Switch S 2-1 Switch S 3-1 Switch S 4-1 The second analog switch unit includes: switch S 1-2 Switch S 2-2 Switch S 3-2 Switch S 4-2 The third analog switch unit includes: switch S 1-3 Switch S 2-3 Switch S 3-3 Switch S 4-3 When the current source output module outputs the maximum range current, the current flows through the first sampling resistor R. S1 Switch S 1-2 Switch S 1-3 Switch S 2-1 Switch S 3-1 and switch S 4-1 Close, switch S 1-1 Switch S 2-2 Switch S 2-3 Switch S 3-2 Switch S 3-3 Switch S 4-2 and switch S 4-3 Disconnect, at this time, due to V L The second sampling resistor R, which is not involved in the measurement, maintains the same potential as the output terminal of the buffer unit. S2 The third sampling resistor R S3 and the fourth sampling resistor R S4 The potentials at both ends are approximately equal, and the leakage current is negligible; when the current source output module outputs the minimum range current, the current flows through the fourth sampling resistor R. S4 Switch S 4-2 Switch S 4-3 Switch S 1-1 Switch S 2-1 and switch S 3-1 Close, switch S 4-1 Switch S 1-2 Switch S 1-3 Switch S 2-2 Switch S 2-3 Switch S 3-2 and switch S 3-3 Disconnected; at this time, the first sampling resistor R, which is not involved in the measurement,S1 Second sampling resistor R S2 and the third sampling resistor R S3 Since the potentials at both ends are approximately equal, the leakage current is also negligible. During the switching of different measurement ranges, the non-measurement branches maintain an equipotential state, thereby effectively suppressing leakage current interference and ensuring the accuracy and stability of current measurement.

[0063] Based on the same technical concept, at least one embodiment also provides a highly stable bidirectional current source, which includes: a current source measurement circuit as described above.

[0064] Based on the same technical concept, at least one embodiment also provides a method of operating a current source measurement circuit as described above, comprising: when the isolating switch module is turned on, the current source output module supplies current to the current output terminal I through the isolating switch module. out The system outputs a controllable forward or reverse current, and the current measurement module detects the controllable forward or reverse current output by the current source output module to correct the output current. When the disconnecting switch module is off, it connects the current source output module to the current output terminal I. out Insulation and isolation.

[0065] In summary, this invention, through the cooperation of a current source output module and an isolating switch module, enables controllable output of both forward and reverse current. Simultaneously, the isolating switch module provides high insulation isolation when the current source output module is not outputting, and possesses low leakage current and reliable on-line switching capability to ensure circuit stability during switching on and off. Furthermore, the current measurement module can accurately measure the output current in real time and feed it back to the current source output module to correct the output. This effectively overcomes the problems of large leakage current interference, poor circuit stability, and insufficient measurement accuracy found in existing current sources.

[0066] The disclosures and other solutions, examples, embodiments, modules, and functional operations described in this document can be implemented in digital electronic circuits, or computer software, firmware, or hardware, including the structures disclosed in this document and their structural equivalents, or combinations thereof. The disclosures and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a tangible and non-volatile computer-readable medium for execution by a data processing apparatus or for controlling the operation of the data processing apparatus. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a storage device, a material composition that influences machine-readable propagated signals, or one or more of these. The terms "data processing unit" or "data processing apparatus" include all means, devices, and machines for processing data, including, for example, programmable processors, computers, or multiprocessors or computer groups. In addition to hardware, the apparatus may also include code that creates an execution environment for a computer program, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, or combinations thereof. The propagated signals are artificially generated signals, such as machine-generated electrical, optical, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiver device.

[0067] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any programming language (including compiled or interpreted languages) and can be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to that program, or in multiple coordinating files (e.g., a file storing one or more modules, subroutines, or portions of code). Computer programs can be deployed and executed on one or more computers located at a single site or distributed across multiple sites interconnected by a communication network.

[0068] The processing and logic flows described in this document can be executed by one or more programmable processors that execute one or more computer programs to perform functions by manipulating input data and generating outputs. The processing and logic flows can also be executed by special-purpose logic circuitry, and the devices can be implemented as special-purpose logic circuitry, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits).

[0069] For example, processors suitable for executing computer programs include general-purpose and special-purpose microprocessors, as well as any one or more of any type of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor that executes instructions and one or more storage devices that store the instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, or operatively coupled to receive data from or transfer data to mass storage devices, or both. However, a computer does not necessarily have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and optical disc read-only memory (CD ROM) and digital versatile optical disc read-only memory (DVD-ROM). The processor and memory may be supplemented by dedicated logic circuitry or incorporated into dedicated logic circuitry.

[0070] While this patent document contains numerous details, it should not be construed as limiting the scope of any invention or claim, but rather as a description of features of specific embodiments of a particular invention. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various functions described in the context of a single embodiment may also be implemented individually in multiple embodiments, or in any suitable sub-combination. Furthermore, although the foregoing features may be described as functioning in certain combinations, or even initially claimed to be so, in certain circumstances, one or more features from a combination of claims may be removed from the combination, and a combination of claims may refer to a sub-combination or a variation of a sub-combination.

[0071] Similarly, although the operations are described in a specific order in the accompanying drawings, this should not be construed as requiring the specific order or sequence shown to perform such operations, or all the described operations, in order to obtain the desired result. Furthermore, the separation of various system components in the embodiments of this patent document should not be construed as requiring such separation in all embodiments.

[0072] Only some implementations and examples are described; other implementations, enhancements, and variations can be made based on the content described and illustrated in this patent document.

[0073] When no intermediate component exists other than a line, trace, or other medium between the first and second components, the first component is directly coupled to the second component. When an intermediate component other than a line, trace, or other medium exists between the first and second components, the first component is indirectly coupled to the second component. The term "coupling" and its variations include direct coupling and indirect coupling. Unless otherwise stated, the term "about" is used to mean a range including upper and lower 10% of the value.

[0074] While several embodiments are provided in this disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of this disclosure. The present examples are intended to be illustrative rather than restrictive and are not limited to the details given. For example, various elements or components may be combined or integrated into another system, or certain features may be omitted or not implemented.

[0075] In the several embodiments provided herein, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0076] Furthermore, without departing from the scope of this disclosure, the discrete or individual technologies, systems, subsystems, and methods described and illustrated in the various embodiments may be combined or integrated with other systems, modules, technologies, or methods. Other items shown or discussed as coupled may be directly connected or indirectly coupled or communicated via some interface, device, or intermediate component in an electrical, mechanical, or other manner. Those skilled in the art can identify other examples of changes, substitutions, and modifications without departing from the spirit and scope of this disclosure.

Claims

1. A measuring circuit for a current source, characterized in that, include: Current source output module, disconnect switch module, and current measurement module; in The isolating switch module and the current measurement module are electrically connected to the current source output module, respectively. When the isolating switch module is turned on, the current source output module outputs a positive controllable current or a reverse controllable current to the current output terminal through the isolating switch module, and the current measurement module detects the positive controllable current or the reverse controllable current output by the current source output module so that the current source output module corrects the output positive controllable current or the reverse controllable current. When the isolating switch module is turned off, it isolates the current source output module from the current output terminal.

2. The current source measurement circuit as described in claim 1, characterized in that, The current source output module includes: a microprocessor and a controllable voltage source; The controllable voltage source and current measurement module are electrically connected to the microprocessor, the controllable voltage source is electrically connected to the isolating switch module, and the current measurement module is electrically connected to the controllable voltage source. The microprocessor drives the controllable voltage source to output a positive or reverse controllable current to the current output terminal via the isolation switch module. The current measurement module detects the forward or reverse controllable current output by the controllable voltage source and feeds the detection signal back to the microprocessor. The microprocessor corrects the forward or reverse controllable current output by the controllable voltage source based on the detection signal.

3. The current source measurement circuit as described in claim 2, characterized in that, The disconnector module includes: a first reed relay, a first field-effect transistor, a second field-effect transistor, a third field-effect transistor, and a first diode; The first terminal of the first reed relay is electrically connected to the current output terminal, the second terminal of the first reed relay is electrically connected to the power supply and the cathode of the first diode, the third terminal of the first reed relay is electrically connected to the anode of the first diode and the drain of the first field-effect transistor, and the fourth terminal of the first reed relay is electrically connected to the drain of the second field-effect transistor. The source of the first field-effect transistor is grounded, the gate of the first field-effect transistor is electrically connected to the first control signal terminal, the source of the second field-effect transistor is electrically connected to the source of the third field-effect transistor, and the gates of the second and third field-effect transistors are electrically connected to the second control signal terminal.

4. The current source measurement circuit as described in claim 3, characterized in that, The first field-effect transistor is turned on or off under the control of the first control signal terminal to control the first reed relay to close or open. When the first reed relay is closed, the second and third field-effect transistors are synchronously turned on under the control of the second control signal terminal, so that the controllable voltage source outputs a positive or reverse controllable current to the current output terminal.

5. The current source measurement circuit as described in claim 3, characterized in that, The current measurement module includes: a sampling resistor unit, a buffer unit, a first analog switch unit, a second analog switch unit, a third analog switch unit, a fourth field-effect transistor, a fifth field-effect transistor, a sixth field-effect transistor, a seventh field-effect transistor, and a signal conditioning unit; The input terminal of the buffer unit, the drain of the third field-effect transistor, and the sampling resistor unit are electrically connected, and the sampling resistor unit is electrically connected to the signal conditioning unit. The output terminal of the buffer unit is electrically connected to the first analog switch unit. The first analog switch unit, the second analog switch, the drain of the fourth field-effect transistor, and the source of the fifth field-effect transistor are electrically connected to the same connection point. The first analog switch unit and the second analog switch unit are electrically connected to the third control signal terminal. The drain of the fifth field-effect transistor is electrically connected to the source of the sixth field-effect transistor, and the gates of the fourth, fifth, sixth, and seventh field-effect transistors are electrically connected to the fourth control signal terminal. The source of the fourth field-effect transistor and the source of the seventh field-effect transistor are electrically connected to the sampling resistor unit. The drain of the seventh field-effect transistor, the second analog switch unit, and the third analog switch unit are connected to the same connection point. The third analog switch unit is electrically connected to the fifth control signal terminal and is also electrically connected to the signal conditioning unit.

6. The current source measurement circuit as described in claim 5, characterized in that, The signal conditioning unit includes: a voltage follower circuit, a proportional amplifier circuit, and a differential circuit; The voltage follower circuit and the proportional amplifier circuit are electrically connected to the third analog switch unit and the sampling resistor unit, respectively, to obtain the sampled voltage, amplify it, and transmit it to the differential circuit to process the common-mode interference until the sampled voltage is output to the microprocessor to calculate the current measurement current.

7. The current source measurement circuit as described in claim 6, characterized in that, The first and second analog switch units are synchronously disconnected under the control of the third control signal terminal, the third analog switch unit is closed under the control of the fifth control signal terminal, and the fourth, fifth, sixth, and seventh field-effect transistors are synchronously turned on under the control of the fourth control signal terminal, so that the voltage follower circuit and the proportional amplifier circuit can collect the forward or reverse controllable current output by the controllable voltage source through the sampling resistor unit.

8. The current source measurement circuit as described in claim 6, characterized in that, The first analog switch unit and the second analog switch unit are closed synchronously under the control of the third control signal terminal, the third analog switch unit is opened under the control of the fifth control signal terminal, the fourth field-effect transistor, the fifth field-effect transistor, the sixth field-effect transistor, and the seventh field-effect transistor are closed synchronously under the control of the fourth control signal terminal, and the buffer unit keeps the two sides of the sampling resistor unit at the same potential.

9. A highly stable bidirectional current source, characterized in that, include: The current source measurement circuit as described in any one of claims 1-8.

10. A method of operating a current source measurement circuit as described in any one of claims 1-8, characterized in that, include: When the disconnecting switch module is turned on, the current source output module outputs a forward controllable current or a reverse controllable current to the current output terminal through the disconnecting switch module, and the current measurement module detects the forward controllable current or the reverse controllable current output by the current source output module so that the current source output module can correct the output forward controllable current or the reverse controllable current. When the isolating switch module is turned off, it isolates the current source output module from the current output terminal.

Images