Multi-path integrated current source for SERF gyroscope three-dimensional magnetic compensation and working method of multi-path integrated current source

Abstract

The invention relates to a multipath integrated current source for SERF gyroscope three-dimensional magnetic compensation and a working method of the multipath integrated current source. A microcontroller controls a four-channel high-precision digital-to-analog converter to output four paths of reference voltage source output; the output of the four reference voltage sources is input into the multi-channel V / I conversion circuit; the multi-channel V / I conversion circuit outputs four-channel numerical control current source excitation by utilizing a multi-channel differential amplifier and a multi-channel operational amplifier on the basis of a dual-operational-amplifier V / I conversion principle. Compared with a scheme of constructing a single-path analog current source by utilizing a field effect transistor and an integrated operational amplifier, the invention realizes the construction of four paths of current sources by only using four chips, and can adjust the magnitude of the output current in a numerical control manner, so that the system is simpler and easier to apply in a miniaturized system, and the cost is reduced. The method has an important value on the development of magnetic field measurement and inertial measurement systems based on atomic spinning, and can serve various fields in the future, especially integrated atomic spinning gyroscopes and magnetometer systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic circuits, and particularly relates to a multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscopes and its working method. Background Art

[0002] Manipulating the atomic spin to be in the SERF state is a prerequisite for realizing an ultra-high-precision atomic spin gyroscope; and a weak magnetic field environment condition is a necessary condition for realizing the atomic spin SERF state. The environmental magnetic field directly affects the gyro output, so active and passive magnetic shielding technologies are required to reduce the environmental residual magnetism as much as possible. Due to the existence of the geomagnetic field, high-performance multi-layer magnetic shielding is needed. However, there are light-passing holes on the shielding barrel that affect the shielding performance and the residual magnetism of the shielding barrel itself. To better realize the SERF gyroscope, active three-dimensional magnetic field compensation is also required on the basis of passive magnetic shielding to further reduce the environmental magnetic field. The stability of the three-dimensional compensation magnetic field itself is also one of the factors determining the zero-bias drift of the gyroscope, and the three-dimensional compensation magnetic field is realized by passing weak currents into three magnetic field coils. The stability of each current output directly determines the effect of three-dimensional magnetic compensation and reducing environmental residual magnetism.

[0003] First of all, during the experiment of three-dimensional magnetic compensation of SERF gyroscopes, more than three weak currents need to be passed into the magnetic field coils; and for the miniaturization of the SERF system, the multi-channel current source system should be as small as possible and the integration degree should be as high as possible. Therefore, the design of a multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscopes is of great significance.

[0004] The main limitations of the existing current source systems are as follows:

[0005] The reference voltage source part is usually composed of an analog circuit or a single-channel voltage source output chip, and a single-channel dual operational amplifier V / I conversion circuit needs to be composed of multiple operational amplifiers and passive resistor devices. If a multi-channel current excitation source is built, a large number of electronic components are required to meet the design requirements, and crosstalk is likely to occur between them, which is not conducive to the miniaturization and integration of the system.

[0006] To solve these problems, Patent CN 202110783578.9 proposed a design scheme of a high-precision constant current source for magnetic field generation. However, this scheme can only provide one current output. If it is used for three-dimensional magnetic field generation, three sets of systems need to be built, and too many components are required, and there is still a problem of a large system volume, which is not conducive to the miniaturization and integration of the system. Summary of the Invention

[0007] The object of the present invention is to overcome the deficiencies of the prior art and propose a multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscopes and its working method. The construction of four current sources is achieved by using only four chips, and the output current magnitude can be numerically controlled and adjusted. The system is simpler and easier to be applied in miniaturized systems, which has important value for the development of magnetic field measurement and inertial measurement systems based on atomic spin, and will serve future fields, especially integrated atomic spin gyroscopes and magnetometer systems.

[0008] The present invention solves its technical problems by adopting the following technical solutions:

[0009] A multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscopes includes a microcontroller, a multi-channel reference voltage source, a multi-channel V / I conversion circuit, and a load coil. Among them, the microcontroller, the multi-channel reference voltage source, the multi-channel V / I conversion circuit, and the load coil are connected in sequence. The microcontroller is used to control the magnitude of the multi-channel current output value. The multi-channel reference voltage source is used to generate adjustable voltages. The multi-channel V / I conversion circuit is used for voltage-to-current conversion, and the three-dimensional magnetic field coil is the load of the current source system.

[0010] Moreover, the multi-channel reference voltage source adopts a four-channel high-precision digital-to-analog converter.

[0011] Moreover, the multi-channel V / I conversion circuit includes a comparator circuit and a follower circuit. The comparator circuit includes a multi-channel differential amplifier and its peripheral circuits. The follower circuit includes a multi-channel operational amplifier and its peripheral circuits.

[0012] A working method of a multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscopes includes the following steps:

[0013] Step 1: The microcontroller controls the output of four-channel reference voltage sources by a four-channel high-precision digital-to-analog converter.

[0014] Step 2: The outputs of the four-channel reference voltage sources are input into the multi-channel V / I conversion circuit.

[0015] Step 3: Based on the dual-op-amp V / I conversion principle, the multi-channel V / I conversion circuit uses a multi-channel differential amplifier and a multi-channel operational amplifier to output four numerically controllable current source excitations.

[0016] The advantages and positive effects of the present invention are:

[0017] The present invention controls a four-channel high-precision digital-to-analog converter through a microcontroller to output four reference voltage sources; the four reference voltage sources are input into a multi-channel V / I conversion circuit; the multi-channel V / I conversion circuit is based on the dual operational amplifier V / I conversion principle, and uses a multi-channel differential amplifier and a multi-channel operational amplifier to output four digitally controllable current source excitations. Compared with the solution of building a single-channel analog current source using a field effect transistor and an integrated operational amplifier, the present invention realizes the construction of four current sources using only four chips, and the output current size can be digitally controlled and adjusted. The system is simpler and easier to be applied in a miniaturized system, which has important value for the research and development of magnetic field measurement and inertial measurement systems based on atomic spin, and will serve future fields, especially integrated atomic spin gyroscopes and magnetometer systems. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of a three-dimensional magnetic field coil of a SERF gyro principle prototype;

[0019] Figure 2 It is a schematic diagram of a single-channel dual operational amplifier V / I conversion circuit of the present invention;

[0020] Figure 3 It is a principle block diagram of a multi-channel integrated digital controllable current source of the present invention;

[0021] Figure 4 It is an internal structure diagram of a multi-channel digital controllable reference voltage source chip of the present invention;

[0022] Figure 5 It is an internal structure diagram of the adder chip AD8277 in the multi-channel V / I conversion circuit of the present invention;

[0023] Figure 6 It is an internal structure diagram of the follower chip AD8664 in the multi-channel V / I conversion circuit of the present invention.

[0024] Label Description:

[0025] 1 - Axial coil (Barker); 2 - Radial coil (saddle). Detailed Embodiment

[0026] The following further details the present invention with reference to the drawings.

[0027] The multi-channel integrated current source for three-dimensional magnetic compensation of a SERF gyro includes a microcontroller, a multi-channel reference voltage source, a multi-channel V / I conversion circuit, and a load coil. Among them, the microcontroller, the multi-channel reference voltage source, the multi-channel V / I conversion circuit, and the load coil are connected in sequence. The microcontroller is used to control the output value size of the multi-channel current, the multi-channel reference voltage source is used to generate an adjustable voltage, the multi-channel V / I conversion circuit is used for voltage-current conversion, and the three-dimensional magnetic field coil is the load of the current source system.

[0028] As Figure 4 shown, the multi-channel reference voltage source adopts a four-channel high-precision digital-to-analog converter. In the present invention, the 16-bit, multi-channel digital-to-analog converter DAC8554 produced by TI is selected to realize the output of the multi-channel reference voltage source. According to the manual and Figure 4 , the size of the DAC8554 is only 6.6*5mm, and it can provide V OUT A to V OUT D four-channel reference voltage outputs, and the output range of each channel is 0 to 5V, which can meet the requirements of three-dimensional magnetic field current drive and has the characteristics of high integration. D IN ports are used to receive microcontroller instructions, and the output voltage of each channel can be adjusted in real time. The output voltage can be calculated as:

[0029]

[0030] Among them, V OUT is the output voltage of each channel of the reference voltage source, V REF is the input reference voltage, L is, D IN is the 16-bit voltage data generated by the multi-channel digital-to-analog converter DAC8554.

[0031] The multi-channel V / I conversion circuit includes a comparator circuit and a follower circuit. The comparator circuit includes a multi-channel differential amplifier and its peripheral circuit, and the follower circuit includes a multi-channel operational amplifier and its peripheral circuit.

[0032] Figure 2 is a schematic diagram of a single-channel dual-op amp V / I conversion circuit. In the figure, V REF is the reference voltage, and R ref is the sampling resistor. The values of the 4 resistors in the box of the attached figure are the same. Among them, the op amp U1 constitutes an adder, and U2 constitutes a follower. Both U1 and U2 are selected as low-noise, low-offset, and high open-loop gain bipolar op amp chips.

[0033] Under ideal conditions, according to the virtual short and virtual open principles of the operational amplifier, the output current can be obtained:

[0034] I O =V REF / R ref

[0035] In the formula: V REF is the input reference voltage (V); R ref is the sampling resistor (Ω).

[0036] As Figure 5 shown and Figure 6 shown, they are respectively the adder chip (such as Figure 2 U1 in Figure 2Internal structure diagram of AD8664 in China. Consisting of Figure 2 It can be seen that a single-channel V / I conversion circuit is generally built by two integrated operational amplifiers and four equal-value resistors. To achieve three-channel current drive, at least 6 integrated operational amplifiers and 12 equal-value resistors are required, involving more lead and device crosstalk problems, as well as the volume problem of the system. The present invention uses a differential amplifier AD8277 and a four-channel operational amplifier AD8664 to build a multi-channel V / I conversion circuit. Among them, the sizes of AD8277 and AD8664 are both 8.7*6mm. AD8277 integrates two operational amplifiers and eight equal-value resistors internally, while AD8664 integrates four operational amplifiers internally. That is, two AD8277s and one AD8664 can complete the construction of a four-channel V / I conversion circuit, meeting the requirements of three-dimensional magnetic field current drive, and also having the advantage of high integration.

[0037] A working method of a multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscopes, comprising the following steps:

[0038] Step 1, the microcontroller controls the four-channel high-precision digital-to-analog converter to output four reference voltage source outputs;

[0039] Step 2, the four reference voltage source outputs are input into the multi-channel V / I conversion circuit;

[0040] Step 3, the multi-channel V / I conversion circuit is based on the dual operational amplifier V / I conversion principle, and uses a multi-channel differential amplifier and a multi-channel operational amplifier to output four digitally controllable current source excitations.

[0041] The present invention controls the four-channel high-precision digital-to-analog converter by the microcontroller to output four reference voltage source outputs; the four reference voltage source outputs are input into the multi-channel V / I conversion circuit; the multi-channel V / I conversion circuit is based on the dual operational amplifier V / I conversion principle, and uses a multi-channel differential amplifier and a multi-channel operational amplifier to output four digitally controllable current source excitations. Compared with the scheme of building a single-channel analog current source using field effect transistors and integrated operational amplifiers, the present invention realizes the construction of four current sources only using four chips, and the output current size can be digitally controlled and adjusted. The system is simpler and easier to be applied in miniaturized systems, which has important value for the development of magnetic field measurement and inertial measurement systems based on atomic spin, and will serve future fields, especially integrated atomic spin gyroscopes and magnetometer systems.

[0042] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation manners. Any other implementation manners obtained by those skilled in the art according to the technical solutions of the present invention also belong to the scope of protection of the present invention.

Claims

1. A multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscope, characterized by: It includes a microcontroller, a multi-channel reference voltage source, a multi-channel V / I conversion circuit and a load coil, wherein the microcontroller, the multi-channel reference voltage source, the multi-channel V / I conversion circuit and the load coil are connected in sequence, wherein the microcontroller is used to control the magnitude of the multi-channel current output value, the multi-channel reference voltage source is used to generate an adjustable voltage, the multi-channel V / I conversion circuit is used for voltage-current conversion, and the three-dimensional magnetic field coil is the load of the current source system.

2. The multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscope according to claim 1, characterized in that: The multi-channel reference voltage source adopts a four-channel high-precision digital-to-analog converter.

3. The multi-channel integrated current source for three-dimensional magnetic compensation of SERF gyroscope according to claim 1, characterized in that: The multi-channel V / I conversion circuit includes a comparator circuit and a follower circuit. The comparator circuit includes a multi-channel differential amplifier and its peripheral circuits, and the follower circuit includes a multi-channel operational amplifier and its peripheral circuits.

4. A method for operating a multi-channel integrated current source for three-dimensional magnetic compensation of a SERF gyroscope according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, the microcontroller controls a four-channel high-precision digital-to-analog converter to output four reference voltage source outputs; Step 2, the outputs of the four reference voltage sources are input into a multi-channel V / I conversion circuit; Step 3: The multi-channel V / I conversion circuit is based on the dual op amp V / I conversion principle and uses a multi-channel differential amplifier and a multi-channel operational amplifier to output four digitally controllable current source excitations.

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