Radio frequency voltage loop stability control circuit for mass spectrum

Abstract

The invention relates to the technical field of mass spectrometer radio frequency power supply control, and discloses a mass spectrum radio frequency voltage loop stable control circuit comprising a power supply module used for supplying power to an operational amplifier through a + 12V power supply pin and used for supplying power and establishing a potential reference; the radio frequency power supply acquisition module is used for inputting a signal to an operational amplifier of the hardware PID control module through a resistance potential-divider network and is used for acquiring and monitoring a voltage signal; according to the radio frequency voltage loop stability control circuit for the mass spectrum, through a cross calibration mechanism in which software control and a hardware PID controller are combined and output voltages of software and hardware circuits are mutual references and mutual constraints, the problem of voltage drift instability caused by long-time work of a mass spectrometer radio frequency power supply is avoided. Meanwhile, hardware PID ensures rapid dynamic response to suppress real-time voltage fluctuation, software control provides long-term stability to overcome the influence of element aging and temperature drift, and the synergistic effect of the hardware PID and the software control realizes voltage stability superior to that of a pure hardware or pure software scheme.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency power supply control for mass spectrometers, in particular to a radio frequency voltage loop stabilization control circuit for mass spectrometers. Background Art

[0002] Mass spectrometry is a high-precision analytical technique used to analyze the molecular or atomic masses in a sample. It is widely used in chemistry, biomedicine, environmental monitoring, food safety, and other fields. In a mass spectrometer, the RF power supply is a key component, primarily responsible for core functions such as ion guidance, mass filtration, and ion trap control. Existing RF power supplies for mass spectrometry primarily include traditional LC oscillator circuits, digitally controlled RF power supplies, and solid-state RF power supplies.

[0003] In existing technologies, parameter drift in traditional LC circuits, caused by aging of analog components or changes in ambient temperature, directly leads to output voltage fluctuations. Purely digital control schemes rely on software algorithms for compensation, but these algorithms have long update cycles, making it difficult to suppress sudden voltage disturbances in real time. Heat accumulation in solid-state power supply switching devices at high frequencies can also introduce voltage offsets through changes in device characteristics. These issues directly impact the mass resolution, ion transmission efficiency, and accuracy of analytical results of mass spectrometers. Especially in precision testing scenarios requiring continuous, long-term operation, voltage drift can lead to data deviations and even experimental failure. Summary of the Invention

[0004] (1) Technical problems solved In view of the shortcomings of the existing technology, the present invention provides a radio frequency voltage loop stabilization control circuit for mass spectrometry, which solves the problem of unstable voltage drift of the radio frequency power supply of the mass spectrometer during long-term operation proposed in the above background technology.

[0005] (2) Technical solution To achieve the above objectives, the present invention is implemented through the following technical solutions: A radio frequency voltage loop stabilization control circuit for mass spectrometry, comprising: The power module supplies power to the operational amplifier through the +12V power pin, which is used to supply power and establish a potential reference; The RF power acquisition module inputs the signal to the operational amplifier of the hardware PID control module through a resistor voltage divider network to collect and monitor the voltage signal; The hardware PID control module implements signal feedback and regulation through the proportional / integral / differential links composed of resistors and capacitors, and superimposes the signals with the software collaborative control module to dynamically adjust the RF voltage and suppress voltage fluctuations. The software collaborative control module uses the digital-to-analog converter output signal to superimpose the hardware PID signal through a resistor network to provide calibration and programmable control; The feedback calibration module feeds back the hardware output signal to the analog-to-digital converter of the software module through resistor voltage division and capacitor filtering, forming a closed-loop control link for feeding voltage back to the software calibration; in: Power module, including: +12V power supply, one end is connected to the positive terminal of the power supply, and the other end is connected to the positive power supply pin of the operational amplifier U5-A, U5-B, U23-A, U23-B and resistor R100; -12V power supply, one end is connected to the negative terminal of the power supply, and the other end is connected to the negative power supply pin of the operational amplifier U5-A, U5-B, U23-A, and U23-B; Common ground terminal, one end is the common ground terminal, and the other end is connected to the negative electrodes of all capacitors, the ground terminals of resistors and the ground pins of operational amplifiers; Capacitor C46, one end of which is connected to the positive power supply pin of U5-A and the other end is connected to the common ground terminal, is used to suppress the interference of power supply ripple on the operational amplifier; RF power acquisition module, including: Resistor R101, one end is connected to R100 and the other end is connected to the common ground; RF power acquisition end, one end is connected to the RF power output, and the other end is connected to the non-inverting input of amplifier U5-A; A hardware PID control module that dynamically adjusts RF voltage and suppresses voltage fluctuations includes: Differential link: resistor R102, one end is connected to the output terminal of U5-A, and the other end is connected to the inverting input terminal of U5-A; Integral link: Capacitor C6, one end is connected to the output of U5-A, and the other end is connected to the inverting input of U5 through resistor R105. Resistor R107, one end is connected to the output of U5-B, and the other end is connected to the common ground. Capacitor C214, one end is connected to the output of U23-A, and the other end is connected to resistor R105, is used to influence the dynamic response of the hardware PID control module; Differential link: Resistor R104, one end is connected to the RF voltage acquisition voltage divider point, and the other end is connected to the U23-A non-inverting input terminal through capacitor C211. Resistor R92 one end is connected to the U23-A output terminal, and the other end is connected to the subsequent circuit; Software collaborative control module, including: The main control voltage is connected to the output of the digital-to-analog converter at one end, and the other end is connected to the non-inverting input of U5-B through resistor R103 to be superimposed with the hardware PID output signal; Capacitor C198, one end of which is connected to the output of the DAC and the other end to resistor R93, is used to filter out high-frequency noise; Resistor R93, one end of which is connected to capacitor C198 and the other end is grounded, used for voltage division or current limiting; Operational amplifier U8-B, one end of which is connected to the output of the digital-to-analog converter, and the other end is connected to the subsequent circuit through resistor R93 for signal buffering or amplification; Capacitor C119, one end of which is connected to resistor R93 and the other end is connected to the common ground terminal, is used to filter out high-frequency noise or coupled signals; Resistor R91, one end of which is connected to the input of operational amplifier U8-B and the other end is connected to the output of the digital-to-analog converter, and is used to set the bias voltage or gain parameters; Feedback calibration module, including: Resistor R106, one end is connected to the output of U5-B, and the other end is connected to the common ground terminal through resistor R109. The voltage divider node is grounded through capacitor C215 and connected to the output of the analog-to-digital converter; Capacitor C8, one end of which is connected to the feedback voltage divider node and the other end is connected to the common ground terminal, is used to filter out high-frequency interference in the feedback signal; Resistor R109 has one end connected to resistor R106 and the other end connected to the common ground, and is used to adapt the output voltage to the input range of the analog-to-digital converter.

[0006] Preferably, the voltage division ratio of the resistors R100 and R101 is , used to attenuate RF high voltage signals to the safe input range of the operational amplifier.

[0007] Preferably, the proportional gain of the hardware PID control module is , by adjusting the resistance value of R102 to change the response speed to the current error.

[0008] Preferably, the time constant of the integral link is , used to eliminate the steady-state offset error of the RF voltage.

[0009] Preferably, the time constant of the differential link is , used to suppress high-frequency noise caused by sudden changes in RF voltage.

[0010] Preferably, the resistors R103 and R107 form a proportional superposition network, and the superposition coefficient is , used to realize the weight distribution of software and hardware control signals.

[0011] Preferably, the voltage division ratio of the resistors R106 and R109 is , used to adapt the output voltage to the input range of the analog-to-digital converter.

[0012] Preferably, the output end of the operational amplifier U5-B is grounded via a resistor 107 to form an integral feedback loop to prevent control lag caused by integral saturation.

[0013] Preferably, the output end of the differential link is connected to the summing node of the hardware PID control module through the resistor R92, and is superimposed with the proportional and integral to form a complete control quantity.

[0014] Preferably, the power module further includes: Capacitor C11, one end is connected to the +12V power supply, and the other end is connected to the common ground terminal, which is used to suppress the interference of power supply ripple on the circuit; Capacitor C0, one end of which is connected to the +12V power supply and the other end to the common ground terminal, is used to further filter out high-frequency noise from the power supply; The hardware PID control module also includes: Capacitor C212, one end of which is connected to the output terminal of U23-B and the other end is connected to the common ground terminal, is used to stabilize the output signal and filter out high-frequency interference; Resistor R108, one end of which is connected to the inverting input of U5-A and the other end is connected to the common ground terminal, is used to adjust the bias voltage of the operational amplifier; Capacitor C2, one end of which is connected to the RF voltage acquisition divider point, and the other end is connected to the common ground terminal, which is used to filter out high-frequency noise in the acquired signal; The software collaborative control module also includes: Capacitor C93, one end of which is connected to the output terminal of the digital-to-analog converter and the other end of which is connected to resistor R93, is used to filter out high-frequency noise in the output signal of the digital-to-analog converter; Resistor R94, one end of which is connected to the inverting input terminal of the operational amplifier U8-B and the other end is connected to the common ground terminal, is used to set the input bias resistance of the operational amplifier; The feedback calibration module further includes: Capacitor C215, one end of which is connected to the feedback voltage divider node and the other end is connected to the common ground terminal, is used to filter out high-frequency interference in the feedback signal and improve the stability of the calibration signal; Resistor R97 has one end connected to the power input terminal and the other end connected to the common ground terminal, and is used to limit the power input current and protect the circuit.

[0015] (3) Beneficial effects The present invention provides a mass spectrometer RF voltage loop stabilization control circuit, which has the following beneficial effects: This RF voltage loop stabilization control circuit for mass spectrometry combines software control with a hardware PID controller. A cross-calibration mechanism uses the output voltages of the hardware and software circuits as a reference and constraint, eliminating the problem of unstable voltage drift caused by long-term operation of the mass spectrometer's RF power supply. The hardware PID ensures fast dynamic response to suppress real-time voltage fluctuations, while the software control provides long-term stability to overcome the effects of component aging and temperature drift. The synergistic effect of these two achieves voltage stability superior to that of pure hardware or software solutions.

[0016] This RF voltage loop stabilization control circuit for mass spectrometry achieves programmable control capabilities through modular design and the interconnection of its components. It supports dynamic software adjustment of control parameters and can adapt to the voltage regulation requirements of the mass spectrometer in various modes, such as ion guidance, mass filtering, and ion trap control. Furthermore, filter capacitors in the differential link and feedback calibration module effectively suppress voltage mutation noise and high-frequency interference, improving overall anti-interference performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the circuit structure of the present invention.

[0018] Figure 2 This is a partial schematic diagram of the power collection module of the present invention.

[0019] Figure 3 Schematic diagram of the hardware PID control module of the present invention.

[0020] Figure 4 Schematic diagram of the software collaborative control module of the present invention.

[0021] Figure 5 It is a partial schematic diagram of the feedback calibration module of the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] Example 1 Reference Figure 1-Figure 5 A mass spectrometer RF voltage loop stabilization control circuit according to a preferred embodiment of the present invention will be described in detail below: The power module supplies power to the operational amplifier through the +12V power pin, which is used to supply power and establish a potential reference; The RF power acquisition module inputs the signal to the operational amplifier of the hardware PID control module through a resistor voltage divider network to collect and monitor the voltage signal; The hardware PID control module implements signal feedback and regulation through the proportional / integral / differential links composed of resistors and capacitors, and superimposes the signals with the software collaborative control module to dynamically adjust the RF voltage and suppress voltage fluctuations. The software collaborative control module uses the digital-to-analog converter output signal to superimpose the hardware PID signal through a resistor network to provide calibration and programmable control; The feedback calibration module feeds back the hardware output signal to the analog-to-digital converter of the software module through resistor voltage division and capacitor filtering, forming a closed-loop control link for feeding voltage back to the software calibration; in: Power module, including: +12V power supply, one end is connected to the positive terminal of the power supply, and the other end is connected to the positive power supply pin of the operational amplifier U5-A, U5-B, U23-A, U23-B and resistor R100; -12V power supply, one end is connected to the negative terminal of the power supply, and the other end is connected to the negative power supply pin of the operational amplifier U5-A, U5-B, U23-A, and U23-B; Common ground terminal, one end is the common ground terminal, and the other end is connected to the negative electrodes of all capacitors, the ground terminals of resistors and the ground pins of operational amplifiers; Capacitor C46, one end of which is connected to the positive power supply pin of U5-A and the other end is connected to the common ground terminal, is used to suppress the interference of power supply ripple on the operational amplifier; RF power acquisition module, including: Resistor R101, one end is connected to R100 and the other end is connected to the common ground; RF power acquisition end, one end is connected to the RF power output, and the other end is connected to the non-inverting input of amplifier U5-A; A hardware PID control module that dynamically adjusts RF voltage and suppresses voltage fluctuations includes: Differential link: resistor R102, one end is connected to the output terminal of U5-A, and the other end is connected to the inverting input terminal of U5-A; Integral link: Capacitor C6, one end is connected to the output of U5-A, and the other end is connected to the inverting input of U5 through resistor R105. Resistor R107, one end is connected to the output of U5-B, and the other end is connected to the common ground. Capacitor C214, one end is connected to the output of U23-A, and the other end is connected to resistor R105, is used to influence the dynamic response of the hardware PID control module; Differential link: Resistor R104, one end is connected to the RF voltage acquisition voltage divider point, and the other end is connected to the U23-A non-inverting input terminal through capacitor C211. Resistor R92 one end is connected to the U23-A output terminal, and the other end is connected to the subsequent circuit; Software collaborative control module, including: The main control voltage is connected to the output of the digital-to-analog converter at one end, and the other end is connected to the non-inverting input of U5-B through resistor R103 to be superimposed with the hardware PID output signal; Capacitor C198, one end of which is connected to the output of the DAC and the other end to resistor R93, is used to filter out high-frequency noise; Resistor R93, one end of which is connected to capacitor C198 and the other end is grounded, used for voltage division or current limiting; Operational amplifier U8-B, one end of which is connected to the output of the digital-to-analog converter, and the other end is connected to the subsequent circuit through resistor R93 for signal buffering or amplification; Capacitor C119, one end of which is connected to resistor R93 and the other end is connected to the common ground terminal, is used to filter out high-frequency noise or coupled signals; Resistor R91, one end of which is connected to the input of operational amplifier U8-B and the other end is connected to the output of the digital-to-analog converter, and is used to set the bias voltage or gain parameters; Feedback calibration module, including: Resistor R106, one end is connected to the output of U5-B, and the other end is connected to the common ground terminal through resistor R109. The voltage divider node is grounded through capacitor C215 and connected to the output of the analog-to-digital converter; Capacitor C8, one end of which is connected to the feedback voltage divider node and the other end is connected to the common ground terminal, is used to filter out high-frequency interference in the feedback signal; Resistor R109 has one end connected to resistor R106 and the other end connected to the common ground, and is used to adapt the output voltage to the input range of the analog-to-digital converter.

[0024] Furthermore, through a hybrid hardware and software control architecture, combining the fast response capability of hardware and the long-term calibration capability of software, the limitations of the single control mode in traditional solutions are solved, while the maintainability and scalability of the circuit are improved through modular design.

[0025] The output end of the operational amplifier U5-B is grounded through the resistor 107 to form an integral feedback loop to prevent control lag caused by integral saturation.

[0026] Furthermore, R107 is introduced to provide an integral feedback path to improve circuit robustness and ensure the accuracy of dynamic response.

[0027] The output end of the differential link is connected to the summing node of the hardware PID control module through resistor R92, and is superimposed with the proportional and integral to form a complete control quantity.

[0028] Furthermore, a single proportional, integral or differential link cannot take into account response speed, steady-state accuracy and anti-interference ability at the same time, while the superposition of the three can achieve optimal control performance, thereby solving the stability problem of complex dynamic systems.

[0029] The signal direction of the circuit is as follows: the output signal of the RF power supply is input into the hardware PID control module after voltage division and filtering by the RF power supply acquisition module. After processing through the proportional, integral and differential links, it is combined with the main control voltage output by the software collaborative control module through the digital-to-analog converter and superimposed through the resistor network to form the final control signal. The signal is then fed back to the software by the analog-to-digital converter after voltage division and filtering by the feedback calibration module, and compared with the target voltage to form a closed loop. This signal direction quickly suppresses real-time voltage fluctuations through the hardware PID and eliminates steady-state errors through the integral link. Combined with the software to calibrate the control parameters based on the feedback for a long time, the cross-calibration mechanism of the output voltage of the hardware and software is used to solve the problem of unstable voltage drift of the mass spectrometer RF power supply during long-term operation and improve the voltage stability.

[0030] The following is the entire working process and working principle of the above embodiment: The power module uses a ±12V dual-power design, with the +12V positive terminal connected to the positive power pins of operational amplifiers U5-A, U5-B, U23-A, and U23-B, providing forward bias voltage for these key signal processing components. The -12V negative terminal is connected to the negative power pins of each operational amplifier, forming a differential power supply structure to ensure stable operation of the operational amplifiers in the linear amplification region. The common ground terminal GND serves as the potential reference point for the entire circuit. It not only connects the negative terminals of all capacitors and the ground terminals of resistors, but also provides an electrical zero point for the operational amplifiers, eliminating potential difference interference between modules and ensuring consistent signal transmission.

[0031] The RF voltage acquisition module uses a resistor divider network, which is composed of a high-resistance resistor R100 and a low-resistance resistor R101 in series. When the RF power supply outputs a high-voltage signal, according to the voltage divider formula , attenuating it to a range of 0-30V. Further processing by the subsequent operational amplifier brings it within the safe ±12V input range. This protects downstream circuit components from high-voltage shocks, and the accuracy of the sampled signal is ensured by the selection of high-precision resistors. To prevent high-frequency noise in the RF signal from interfering with the sampling process, a filter capacitor C101 is connected in parallel between the voltage divider node and ground, forming an RC low-pass filter that effectively filters out noise components above this frequency.

[0032] The hardware PID control module consists of three parts: proportional, integral, and differential. Among them, the proportional part connects the output terminal and the inverting input terminal of U5-A through resistor R102 to form a voltage series negative feedback structure. According to the virtual short and virtual open characteristics of the operational amplifier, the proportional gain can be expressed as , which can speed up the system's response to errors. The integral link is composed of capacitor C6 and resistor R105 in series, connected between the output of U5-A and the inverting input of U5-B. Its time constant T1 = R105 × C6 = 1s determines the rate of error accumulation. During operation, when there is a steady-state error in the system, the integral link will continue to accumulate the error over time until the error is eliminated. The differential link is composed of resistor R104 and capacitor C211 in series, connected between the RF voltage divider point and the non-inverting input of U23-A. Its transfer function is GD(s) = R104 × C'211 × S. It has a sensitive response characteristic to high-frequency error signals, can predict the error change trend and provide regulatory effects in advance, and effectively suppress system oscillations caused by voltage mutations.

[0033] The software collaborative control module outputs a digital control signal through the digital-to-analog converter, which is input to the non-inverting input terminal of U5-B through resistor R103 and superimposed with the hardware PID output signal. This determines the weight distribution of software and hardware control. This design allows the system to dynamically adjust control strategies based on different operating states: during the initial startup phase, software control enables rapid parameter configuration; during stable operation, the hardware PID controller provides primary control, while the software performs fine-tuning and calibration; and when sudden voltage disturbances are detected, the hardware control weight can be temporarily increased to achieve an emergency response. An RC filter network is added to the output of the digital-to-analog converter to ensure smooth fusion of the digital and analog signals, filter out high-frequency step ripple in the digital signal, and improve signal quality.

[0034] The feedback calibration module uses a voltage divider network composed of resistors R106 and R109 to attenuate the control voltage output of U5-B to a range of ±1.09V. This is then converted to a 0-3.3V signal through a bias circuit, matching the input range of the analog-to-digital converter. To improve the feedback signal's immunity to interference, capacitor C215 is connected in parallel between the voltage divider node and ground. Together with the voltage divider resistors, it forms a low-pass filter with a cutoff frequency of approximately 159Hz. This effectively attenuates high-frequency noise from the power supply or RF source. The analog-to-digital converter converts the feedback voltage into a digital signal and feeds it into a microcontroller for processing. The microcontroller uses an algorithm to adjust the DAC output based on the deviation between the preset target voltage and the feedback value, forming a complete closed-loop control loop. This closed-loop calibration mechanism monitors and compensates for drift and errors in the system in real time, ensuring long-term stability of the RF voltage output within a specified range.

[0035] R107 is connected between the output of U5-B and ground, providing a discharge path for the integral capacitor C6. When the system starts or the parameters change suddenly, the integral capacitor may be overcharged, causing the operational amplifier to enter a saturated state, affecting the control effect. R107 allows the integral capacitor to discharge quickly when needed, avoiding the integral saturation problem and ensuring that the integral link operates in the linear region. Resistor R92 connects the output of the differential link to the inverting input of U5-A to achieve a complete superposition of the three elements of PID. This allows the output signals of the proportional, integral, and differential links to be summed at the same node to form a complete PID control law, thereby giving full play to the advantages of PID control and taking into account the system's rapid responsiveness, steady-state accuracy, and anti-interference ability.

[0036] Example 2 Reference Figure 1-Figure 5 , the voltage divider ratio of resistors R100 and R101 is , used to attenuate RF high voltage signals to the safe input range of the operational amplifier.

[0037] Further, through Make sure the voltage input to the operational amplifier is within its rated range to avoid high voltage damaging the components.

[0038] The proportional gain of the hardware PID control module is , by adjusting the resistance value of R102 to change the response speed to the current error.

[0039] Furthermore, gain adjustment is achieved through the adjustable resistor R102, so that the circuit can balance response speed and stability according to actual needs, avoiding the problem that fixed gain cannot adapt to different working conditions.

[0040] The time constant of the integral link is , used to eliminate the steady-state offset error of the RF voltage.

[0041] Furthermore, the integral link achieves zero-error regulation by accumulating errors, ensuring voltage accuracy during long-term operation and solving the drift problem caused by component aging in traditional LC circuits.

[0042] The time constant of the differential link is , used to suppress high-frequency noise caused by sudden changes in RF voltage.

[0043] Furthermore, the mass spectrometer may experience rapid voltage changes in scanning mode, so the differential link provides damping by predicting the error change trend, reducing overshoot and oscillation, and improving circuit stability. It is especially suitable for scenarios with high dynamic response requirements.

[0044] Resistors R103 and R107 form a proportional superposition network, and the superposition coefficient is , used to realize the weight distribution of software and hardware control signals.

[0045] Furthermore, through adjustable weight distribution, the circuit can flexibly switch between hardware-led fast response and software-led long-term calibration, adapting to different working modes and improving control flexibility.

[0046] The voltage divider ratio of resistors R106 and R109 is , used to adapt the output voltage to the input range of the analog-to-digital converter.

[0047] Furthermore, analog-to-digital converters can usually only process low-voltage signals. The voltage divider network is a necessary link in the feedback chain to ensure that the software can accurately obtain the output voltage data, thereby achieving closed-loop calibration and avoiding calibration errors caused by signal mismatch.

[0048] The power module further includes: Capacitor C11, one end is connected to the +12V power supply, and the other end is connected to the common ground terminal, which is used to suppress the interference of power supply ripple on the circuit; Capacitor C0, one end of which is connected to the +12V power supply and the other end to the common ground terminal, is used to further filter out high-frequency noise from the power supply; The hardware PID control module also includes: Capacitor C212, one end of which is connected to the output terminal of U23-B and the other end is connected to the common ground terminal, is used to stabilize the output signal and filter out high-frequency interference; Resistor R108, one end of which is connected to the inverting input of U5-A and the other end is connected to the common ground terminal, is used to adjust the bias voltage of the operational amplifier; Capacitor C2, one end of which is connected to the RF voltage acquisition divider point, and the other end is connected to the common ground terminal, which is used to filter out high-frequency noise in the acquired signal; The software collaborative control module also includes: Capacitor C93, one end of which is connected to the output terminal of the digital-to-analog converter and the other end of which is connected to resistor R93, is used to filter out high-frequency noise in the output signal of the digital-to-analog converter; Resistor R94, one end of which is connected to the inverting input terminal of the operational amplifier U8-B and the other end is connected to the common ground terminal, is used to set the input bias resistance of the operational amplifier; The feedback calibration module also includes: Capacitor C215, one end of which is connected to the feedback voltage divider node and the other end is connected to the common ground terminal, is used to filter out high-frequency interference in the feedback signal and improve the stability of the calibration signal; Resistor R97 has one end connected to the power input terminal and the other end connected to the common ground terminal, and is used to limit the power input current and protect the circuit.

[0049] Furthermore, capacitor C215 acts as a filter capacitor, and utilizes the characteristics of passing low frequencies and blocking high frequencies to attenuate high-frequency noise in the feedback signal.

[0050] The following is the entire working process and working principle of the above embodiment: In the signal conditioning stage, the RF voltage acquisition module utilizes a voltage divider network formed by R100 and R101 to precisely attenuate the multi-kilovolt RF high-voltage signal to a safe range that the operational amplifier can handle. For example, it converts a 3000V signal into a 10V sampling signal, preventing overvoltage damage to components. The feedback calibration module uses voltage dividers R106 and R109 to adapt the ±12V output control voltage to a range that the analog-to-digital converter can recognize. To ensure voltage division accuracy, the circuit uses high-precision metal film resistors to effectively reduce the impact of temperature drift on the voltage divider ratio, ensuring accurate signal acquisition.

[0051] The hardware PID control module changes the proportional gain by adjusting the resistance of R102. This resistor, together with R101, forms a negative feedback loop, amplifying the current error signal to accelerate system response. However, excessive gain can cause overshoot, so Bode plot analysis is required during design to ensure that the phase margin meets stability requirements. The time constant of the integral circuit formed by C6 and R105 determines the rate of elimination of steady-state errors. This effectively compensates for voltage drift caused by component aging and temperature changes during long-term operation of the mass spectrometer. The differential circuit formed by R104 and C211 is extremely sensitive to sudden voltage changes and can quickly output a suppression signal, reducing system oscillations and improving anti-interference capabilities.

[0052] The software collaborative control module dynamically allocates control weights between software and hardware through a resistor network. The resistance ratio of R103 and R107 determines the superposition coefficient between the digital signal output by the DAC and the hardware PID signal, enabling the system to flexibly switch control modes based on operating conditions. During startup, software calibration is primarily used for rapid parameter setting. During stable operation, software and hardware collaborative control is employed, prioritizing hardware response when encountering interference.

[0053] The C215 capacitor and the voltage-divider resistor form a low-pass filter. This filter can attenuate high-frequency noise above 50kHz, such as power switching harmonics and radio frequency spurious signals, by more than 40dB. Combined with the RC filter network at the front end of the analog-to-digital converter, it further reduces the intensity of interference signals and ensures that the feedback signal only reflects actual voltage changes.

Claims

1. A radio frequency voltage loop stabilization control circuit for mass spectrometry, characterized in that: include: The power module supplies power to the operational amplifier through the +12V power pin, which is used to supply power and establish a potential reference; The RF power acquisition module inputs the signal to the operational amplifier of the hardware PID control module through a resistor voltage divider network to collect and monitor the voltage signal; The hardware PID control module implements signal feedback and regulation through the proportional / integral / differential links composed of resistors and capacitors, and superimposes the signals with the software collaborative control module to dynamically adjust the RF voltage and suppress voltage fluctuations. The software collaborative control module uses the digital-to-analog converter output signal to superimpose the hardware PID signal through a resistor network to provide calibration and programmable control; The feedback calibration module feeds back the hardware output signal to the analog-to-digital converter of the software module through resistor voltage division and capacitor filtering, forming a closed-loop control link for feeding voltage back to the software calibration; in: Power module, including: +12V power supply, one end is connected to the positive terminal of the power supply, and the other end is connected to the positive power supply pin of the operational amplifier U5-A, U5-B, U23-A, U23-B and resistor R100; -12V power supply, one end is connected to the negative terminal of the power supply, and the other end is connected to the negative power supply pin of the operational amplifier U5-A, U5-B, U23-A, and U23-B; Common ground terminal, one end is the common ground terminal, and the other end is connected to the negative electrodes of all capacitors, the ground terminals of resistors and the ground pins of operational amplifiers; Capacitor C46, one end of which is connected to the positive power supply pin of U5-A and the other end is connected to the common ground terminal, is used to suppress the interference of power supply ripple on the operational amplifier; RF power acquisition module, including: Resistor R101, one end is connected to R100 and the other end is connected to the common ground; RF power acquisition end, one end is connected to the RF power output, and the other end is connected to the non-inverting input of amplifier U5-A; Hardware PID control module, including: Differential link: resistor R102, one end is connected to the output terminal of U5-A, and the other end is connected to the inverting input terminal of U5-A; Integral link: Capacitor C6, one end is connected to the output of U5-A, and the other end is connected to the inverting input of U5 through resistor R105. Resistor R107, one end is connected to the output of U5-B, and the other end is connected to the common ground. Capacitor C214, one end is connected to the output of U23-A, and the other end is connected to resistor R105, is used to influence the dynamic response of the hardware PID control module; Differential link: Resistor R104, one end is connected to the RF voltage acquisition voltage divider point, and the other end is connected to the U23-A non-inverting input terminal through capacitor C211. Resistor R92 one end is connected to the U23-A output terminal, and the other end is connected to the subsequent circuit; Software collaborative control module, including: The main control voltage is connected to the output of the digital-to-analog converter at one end, and the other end is connected to the non-inverting input of U5-B through resistor R103 to be superimposed with the hardware PID output signal; Capacitor C198, one end of which is connected to the output of the DAC and the other end to resistor R93, is used to filter out high-frequency noise; Resistor R93, one end of which is connected to capacitor C198 and the other end is grounded, used for voltage division or current limiting; Operational amplifier U8-B, one end of which is connected to the output of the digital-to-analog converter, and the other end is connected to the subsequent circuit through resistor R93 for signal buffering or amplification; Capacitor C119, one end of which is connected to resistor R93 and the other end is connected to the common ground terminal, is used to filter out high-frequency noise or coupled signals; Resistor R91, one end of which is connected to the input of operational amplifier U8-B and the other end is connected to the output of the digital-to-analog converter, and is used to set the bias voltage or gain parameters; Feedback calibration module, including: Resistor R106, one end is connected to the output of U5-B, and the other end is connected to the common ground terminal through resistor R109. The voltage divider node is grounded through capacitor C215 and connected to the output of the analog-to-digital converter; Capacitor C8, one end of which is connected to the feedback voltage divider node and the other end is connected to the common ground terminal, is used to filter out high-frequency interference in the feedback signal; Resistor R109 has one end connected to resistor R106 and the other end connected to the common ground, and is used to adapt the output voltage to the input range of the analog-to-digital converter.

2. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The voltage division ratio of the resistors R100 and R101 is , used to attenuate RF high voltage signals to the safe input range of the operational amplifier.

3. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The proportional gain of the hardware PID control module is , by adjusting the resistance value of R102 to change the response speed to the current error.

4. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The time constant of the integral link is , used to eliminate the steady-state offset error of the RF voltage.

5. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The time constant of the differential link is , used to suppress high-frequency noise caused by sudden changes in RF voltage.

6. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The resistors R103 and R107 form a proportional superposition network, and the superposition coefficient is , used to realize the weight distribution of software and hardware control signals.

7. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The voltage division ratio of the resistors R106 and R109 is , used to adapt the output voltage to the input range of the analog-to-digital converter.

8. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The output end of the operational amplifier U5-B is grounded via the resistor 107 to form an integral feedback loop to prevent control lag caused by integral saturation.

9. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The output end of the differential link is connected to the summing node of the hardware PID control module through the resistor R92, and is superimposed with the proportional and integral to form a complete control quantity.

10. The radio frequency voltage loop stabilization control circuit for mass spectrometry according to claim 1, characterized in that: The power module further includes: Capacitor C11, one end is connected to the +12V power supply, and the other end is connected to the common ground terminal, which is used to suppress the interference of power supply ripple on the circuit; Capacitor C0, one end of which is connected to the +12V power supply and the other end to the common ground terminal, is used to further filter out high-frequency noise from the power supply; The hardware PID control module also includes: Capacitor C212, one end of which is connected to the output terminal of U23-B and the other end is connected to the common ground terminal, is used to stabilize the output signal and filter out high-frequency interference; Resistor R108, one end of which is connected to the inverting input of U5-A and the other end is connected to the common ground terminal, is used to adjust the bias voltage of the operational amplifier; Capacitor C2, one end of which is connected to the RF voltage acquisition divider point, and the other end is connected to the common ground terminal, which is used to filter out high-frequency noise in the acquired signal; The software collaborative control module also includes: Capacitor C93, one end of which is connected to the output terminal of the digital-to-analog converter and the other end of which is connected to resistor R93, is used to filter out high-frequency noise in the output signal of the digital-to-analog converter; Resistor R94, one end of which is connected to the inverting input terminal of the operational amplifier U8-B and the other end is connected to the common ground terminal, is used to set the input bias resistance of the operational amplifier; The feedback calibration module further includes: Capacitor C215, one end of which is connected to the feedback voltage divider node and the other end to the common ground terminal, is used to filter out high-frequency interference in the feedback signal and improve the stability of the calibration signal; Resistor R97 has one end connected to the power input terminal and the other end connected to the common ground terminal, and is used to limit the power input current and protect the circuit.

Images