Bidirectional constant current source for quantum gravimeter

Abstract

The application relates to a bidirectional constant current source for a quantum gravimeter, which comprises a microcontroller MCU, a digital-analog conversion circuit, a power amplifier N, a load Z L , impedance Z C , gain G, an analog-digital conversion circuit; a positive and negative reference voltage V ref generated by the digital-analog conversion circuit of the output signal of the microcontroller MCU flows into the positive end of the power amplifier N, the output end of the power amplifier is connected with the load Z L , then passes through a sampling resistor R S and is grounded, meanwhile, the output end of the power amplifier N passes through impedance Z C and is connected with the negative end of the power amplifier N; the gain G amplifies the voltage between the two ends of the sampling resistor R S to obtain a feedback voltage Vf which is sent into the negative end of the power amplifier N, meanwhile, the feedback voltage Vf is sent into the input end of the microcontroller MCU through the analog-digital conversion circuit. The scheme only needs to use one power amplifier, can realize the bidirectional constant current source, reduces the quantity of power devices, improves the reliability, and is beneficial to miniaturization design.

Description

Technical Field

[0001] This invention relates to the field of quantum precision measurement technology, and more specifically to a bidirectional constant current source for a quantum gravimeter. Background Technology

[0002] In the periodic operation of a quantum gravimeter, including atomic cooling, confinement, interference, and detection, the magnetic field control module needs to periodically control the MOT magnetic field, bias magnetic field, and compensation magnetic field, switching their on / off states and field strengths according to a specific time sequence to achieve precise manipulation of the atomic clusters within the gravity sensor. Therefore, a constant current source with rapid feedback control capabilities and the ability to dynamically track the reference magnetic field is essential.

[0003] Currently, constant current sources are mainly divided into digital and analog types. Digital constant current sources use PWM (Pulse Width Modulation) technology to control the switching transistor's on / off state, thereby changing the output current. This control method introduces a large number of harmonics, which cannot meet the technical requirements of precise magnetic field control in quantum precision measurement. Analog constant current sources mainly utilize the volt-ampere characteristics of semiconductor power amplification devices in the linear amplification region, controlling the current output by changing the base voltage of the semiconductor power device. The semiconductor power devices used in this method are often large in package, and achieving bidirectional controllability requires twice the number of devices, increasing reliability risks and hindering product miniaturization design. Summary of the Invention

[0004] This invention addresses the shortcomings of existing digital constant current sources, such as insufficient accuracy and excessive size of analog constant current sources, by providing a novel bidirectional constant current source for quantum gravimeters. This invention features low noise, high stability, and small size, and can better meet the requirements of magnetic field control technology for quantum gravimeters.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A bidirectional constant current source for a quantum gravimeter, comprising a microcontroller (MCU), a digital-to-analog converter circuit, a power amplifier (N), and a load (Z). L impedance Z C Gain G, analog-to-digital converter circuit; positive and negative reference voltages V generated by the digital-to-analog converter circuit from the output signal of the microcontroller (MCU). ref The power amplifier's output is connected to the load Z, with the current flowing into the positive terminal N. L Then, after passing through the sampling resistor R S Grounded, and the output of power amplifier N is connected to impedance Z. C It is then connected to the negative terminal of power amplifier N; the gain G affects the sampling resistor R. S The voltages at both ends are amplified to obtain a feedback voltage Vf, which is then fed into the negative terminal of the power amplifier N. Simultaneously, the feedback voltage Vf is fed into the input terminal of the microcontroller MCU through an analog-to-digital converter circuit.

[0006] Furthermore, the microcontroller (MCU) generates corresponding voltage control commands based on the feedback voltage Vf, and these voltage control commands are converted into positive and negative reference voltages V by the digital-to-analog converter circuit. ref It flows into the positive terminal N of the power amplifier.

[0007] Furthermore, it also includes an operational amplifier N3, which has three inputs and two outputs. The first input is connected to a reference voltage, the second input is connected to the output of the digital-to-analog converter circuit, and the third input is connected to the output of the gain G. The output of the digital-to-analog converter circuit is subtracted from the reference voltage by the operational amplifier N3 to generate positive and negative reference voltages V. ref Then, the first output of operational amplifier N3 flows into the positive terminal of power amplifier N. The output of gain G is followed by operational amplifier N3, and then sent to the input terminal of analog-to-digital converter circuit through the second output of operational amplifier N3.

[0008] Furthermore, it also includes an analog switch D4. The output of the gain G is followed by an operational amplifier N3, and then fed into the input terminal of the analog-to-digital converter circuit through the second output of the operational amplifier N3 and the switching of the analog switch D4.

[0009] Furthermore, it also includes at least one operational amplifier N32, which has one input and one output. One input is connected to the output of the digital-to-analog converter circuit. After amplifying the output of the digital-to-analog converter circuit, it is output to the second input terminal of the operational amplifier N3.

[0010] The beneficial effects of this invention are: firstly, this solution does not use a switching transistor, thus it does not introduce a large number of harmonics like a digital constant current source, which affects the output quality; secondly, this solution uses the power amplifier OP547FKTWT, which has the characteristic of small size; finally, this invention only requires one power amplifier to realize a bidirectional constant current source, which reduces the number of power devices, improves reliability, and is conducive to miniaturization design. Attached Figure Description

[0011] Figure 1 A block diagram of a bidirectional constant current source for a quantum gravimeter provided in this embodiment of the invention;

[0012] Figure 2 The core circuit diagram of the bidirectional constant current source provided in the embodiments of the present invention;

[0013] in:

[0014] N3: Operational amplifier, N4: Power amplifier, U6: Instrumentation amplifier, R36: Sampling resistor

[0015] R26, R27, R28, R32, R34, R35, R631, R632, R633, R631, R701: Resistors; C62, C802: Capacitors;

[0016] Figure 3 This is a circuit diagram for an analog-to-digital converter.

[0017] in:

[0018] D4: Analog switch; U14: Analog-to-digital converter chip; R102, R103, R104, R105, R106: Resistors; C134, C135, C136, C137, C138, C139: Capacitors.

[0019] Figure 4 This is a circuit diagram for a digital-to-analog converter.

[0020] in:

[0021] D5: Digital-to-analog converter chip; N32: Operational amplifier; R426, R430, R431, R435, R456, R453, R459, R449, R450, R457: Resistors; C334, C336: Capacitors; J17: Connector. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In the description of this application, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0025] This invention provides a bidirectional constant current source for a quantum gravimeter, such as... Figure 1 As shown, it includes a microcontroller (MCU), a digital-to-analog converter (DAC), a power amplifier (N), and a load (Z). L impedance Z C Gain G, analog-to-digital conversion circuit.

[0026] The microcontroller (MCU) outputs a control voltage command to the digital-to-analog converter (DAC) module, which then generates positive and negative reference voltages V. ref The voltage flows into the positive terminal N of the power amplifier, utilizing the amplifier's "virtual short" and "virtual open" characteristics to obtain stable positive and negative output voltages. The output terminal of the power amplifier is connected to the load Z. L Then, after passing through the sampling resistor R S Grounded, and the output of power amplifier N is connected to impedance Z. C It is then connected to the negative terminal of power amplifier N; the gain G affects the sampling resistor R. S The voltage across the two terminals is amplified to obtain a feedback voltage Vf, which is then fed into the negative terminal of power amplifier N, forming the first stage of feedback. Simultaneously, the feedback voltage Vf is converted into voltage data by an analog-to-digital converter and sent to the input of the microcontroller (MCU). The MCU processes this data using an algorithm to generate a corresponding voltage control command. This command then generates a reference voltage V through a digital-to-analog converter (DA converter). ref This completes the second-level feedback control.

[0027] This solution does not use switching transistors, so it does not introduce a large number of harmonics like digital constant current sources, which would affect the output quality. Secondly, this solution uses the OP547FKTWT power amplifier, which is small in size. Finally, this invention only requires one power amplifier to realize a bidirectional constant current source, which reduces the number of power devices, improves reliability, and is conducive to miniaturization design.

[0028] Preferably, the bidirectional constant current source in this embodiment further includes an operational amplifier N3. The operational amplifier N3 has three inputs and two outputs. The first input is connected to a reference voltage, the second input is connected to the output of the digital-to-analog converter circuit, and the third input is connected to the output of the gain G, i.e., the instrumentation amplifier U6. The output of the digital-to-analog converter circuit is subtracted from the reference voltage by the operational amplifier N3 to generate positive and negative reference voltages V. ref Then, the first output of operational amplifier N3 flows into the positive terminal of power amplifier N. The gain G, i.e. the output of instrumentation amplifier U6, is followed by operational amplifier N3, and then sent to the input terminal of analog-to-digital converter circuit through the second output of operational amplifier N3.

[0029] Preferably, the bidirectional constant current source in this embodiment further includes an analog switch D4. The output of the instrumentation amplifier U6 is followed by the operational amplifier N3, and then fed into the input terminal of the analog-to-digital converter U14 through the second output of the operational amplifier N3 and the switching of the analog switch D4.

[0030] Preferably, the bidirectional constant current source in this embodiment further includes at least one operational amplifier N32. The operational amplifier N32 includes one input and one output. One input is connected to the output of the digital-to-analog converter circuit. After amplifying the output of the digital-to-analog converter circuit, it is output to the second input terminal of the operational amplifier N32.

[0031] Specifically, such as Figure 2-4 As shown, when the bidirectional constant current source is powered on, the external reference input Vout8 is subtracted from the reference voltage REF5V0 by the operational amplifier N3 to obtain a control signal with a positive and negative voltage range (e.g., -5 to +5). This signal is provided to the power amplifier N4, which utilizes the characteristics of "virtual short" and "virtual open" to obtain the desired output voltage coil8+ connected to the positive terminal of the coil (load), thus achieving bidirectional constant current control. The negative terminal of the coil (load), coil8-, is grounded through the sampling resistor R36, forming a complete loop. The instrumentation amplifier U6 acquires the voltage across the sampling resistor R36 and amplifies it with appropriate internal gain to obtain the actual output voltage at the power amplifier terminal. This voltage is then introduced into the negative terminal of the power amplifier N4 to form a feedback loop, ensuring that the output voltage can stably track the reference voltage and obtain a stable target magnetic field. The actual output voltage is followed by the operational amplifier N3 and then connected to the positive terminal of the coil (load) via the auxiliary circuit. Figure 3 The switching of analog switch D4 is connected to AD chip U14. The sampled data is processed by the control algorithm in the processor and converted into a new control voltage command, which is then transmitted via an auxiliary circuit. Figure 4 The DA chip D5 and operational amplifier N32 amplify the voltage to obtain a new reference voltage Vout8, forming the second stage of feedback control. This ultimately completes the output control of the constant current source.

[0032] It should also be understood that those skilled in the art can modify the above structure, for example by adding multiple digital-to-analog converters D5 and operational amplifiers N32, thereby expanding the present embodiment to include multiple bidirectional constant current sources.

[0033] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0034] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A bidirectional constant current source for a quantum gravimeter, characterized by, A microcontroller MCU, a digital-analog conversion circuit, a power amplifier N, a load Z L , an impedance Z C , a gain G, an analog-digital conversion circuit; an output signal of the microcontroller MCU generates a positive and negative reference voltage V ref flowing into the positive end of the power amplifier N, the output end of the power amplifier connecting the load Z L , then passing through a sampling resistor R S grounding, while the output end of the power amplifier N connects the negative end of the power amplifier N after passing through the impedance Z C ; the gain G amplifies the voltage across the sampling resistor R S to obtain a feedback voltage Vf which is sent into the negative end of the power amplifier N, while the feedback voltage Vf is sent into the input end of the microcontroller MCU through the analog-digital conversion circuit. Also included is an operational amplifier N3, which includes three inputs and two outputs, wherein the first input is connected to a reference voltage, the second input is connected to the output of the digital-to-analog conversion circuit, and the third input is connected to the output of the gain G, and the output of the digital-to-analog conversion circuit is subjected to subtraction with the reference voltage through the operational amplifier N3 to generate the positive and negative reference voltages V ref The output of the gain G is then followed through the operational amplifier N3 and then sent to the input end of the analog-to-digital conversion circuit through the second output of the operational amplifier N3.

2. The bidirectional constant current source of claim 1, wherein, The microcontroller MCU generates corresponding voltage control instructions according to the feedback voltage Vf, and the voltage control instructions generate positive and negative reference voltages V ref The power amplifier N flows into the positive end.

3. The bidirectional constant current source of claim 1, wherein, Analog switch D4 is further included, the output of the gain G is followed by operational amplifier N3, and then through the second path output of operational amplifier N3 and the switching of analog switch D4, and is sent to the input end of the analog-digital conversion circuit.

4. The bidirectional constant current source of claim 1, wherein, At least one operational amplifier N32 is further included, the operational amplifier N32 includes one input and one output, wherein the one input is connected to the output of the digital-analog conversion circuit, and after the output of the digital-analog conversion circuit is amplified, the one output is connected to the second path input end of operational amplifier N3.

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