Hollow cathode lamp control system of spectrograph

Abstract

The utility model provides a hollow cathode lamp control system of a spectrograph, and relates to the field of control circuits. Comprising an AC input unit, a rectification boost circuit, a high common mode current sampling circuit, a forward and reverse and current switching circuit, a hollow cathode lamp, a switch tube Q3, a voltage regulation circuit, a control unit, a power switch circuit, an isolation amplification circuit, an interface circuit and a main and auxiliary board switching circuit. According to the utility model, the rectification boost circuit, the high common mode current sampling circuit, the voltage regulation circuit and the isolation amplification circuit are arranged to realize real-time data acquisition, and the working state and performance parameters of the hollow cathode lamp can be timely acquired; the brightness is accurately adjusted through the control unit, the switch tube Q3 and the forward and reverse and current switching circuit according to the working state of the hollow cathode lamp, so that stable operation and high-efficiency output of a lighting system are ensured; double control units are achieved through the main and auxiliary board switching circuit, and the double control units can work independently and can also be matched with other control units.

Description

TECHNICAL FIELD

[0001] The utility model relates to control circuit field especially relates to a hollow cathode lamp control system of spectrometer. BACKGROUND

[0002] In today's rapidly developing society, automation technology is increasingly popular due to its outstanding efficiency and accuracy. In particular, in laboratory environments, in order to reduce human error and improve experimental precision, the application of automation technology is particularly important. Various research and experiments in the laboratory require highly accurate data collection and processing, and the introduction of automation systems can effectively replace traditional manual operations, thereby ensuring the reliability and accuracy of experimental results. Therefore, with the development of automation technology, laboratory research work can be carried out more efficiently and accurately, providing strong support for scientific research and technological innovation.

[0003] In traditional hollow cathode lamp systems, due to the lack of automatic control and information collection functions, brightness adjustment usually needs to rely on manual operation. This manual operation method has many limitations, including the inability to achieve precise control of the brightness of the cathode lamp and the inapplicability to centralized control systems. Due to the lack of real-time data collection and feedback mechanisms, operators cannot accurately understand the current state of the cathode lamp and its performance parameters, which poses a challenge to ensuring the stability and efficiency of the light system. SUMMARY

[0004] Therefore, the utility model aims at providing a hollow cathode lamp control system of spectrometer, which solves the problem of insufficient brightness adjustment precision caused by the need for manual operation in the existing hollow cathode lamp system.

[0005] The utility model provides a hollow cathode lamp control system of spectrometer, which comprises: an alternating current input unit, a rectifier boost circuit, a high common mode current sampling circuit, a forward and reverse and current switching circuit, a hollow cathode lamp, a switch tube Q3, a voltage regulation circuit, a control unit, a power switch circuit, an isolation amplification circuit and an interface circuit.

[0006] The alternating current input unit is connected with the rectifier boost circuit and the power switch circuit, and the control unit is connected with the power switch circuit.

[0007] The rectifier boost circuit, the high common mode current sampling circuit, the voltage regulation circuit, the forward and reverse and current switching circuit and the hollow cathode lamp are connected in sequence.

[0008] The control unit, the switch tube Q3 and the forward and reverse and current switching circuit are connected in sequence.

[0009] The control unit is connected with the voltage regulation circuit.

[0010] The high common-mode current sampling circuit, the isolation amplification circuit and the control unit are connected in sequence, and the control unit is connected with the interface circuit.

[0011] Preferably,

[0012] The forward and reverse and current switching circuit comprises a single-pole single-throw normally open relay K2 and a double-pole double-throw change-over relay K1.

[0013] The high common-mode current sampling circuit, the single-pole single-throw normally open relay K2, the double-pole double-throw change-over relay K1 and the hollow cathode lamp are connected in sequence.

[0014] Preferably,

[0015] The control unit comprises a sub-control board, a main control board and a main-sub board switching circuit.

[0016] The interface circuit is connected with the sub-control board.

[0017] The main-sub board switching circuit is connected with the sub-control board, the main control board, the switching tube Q3, the isolation amplification circuit and the power switch circuit.

[0018] Preferably,

[0019] The main-sub board switching circuit comprises a double-pole double-throw change-over relay K3 and a double-pole double-throw change-over relay K5.

[0020] The double-pole double-throw change-over relay K3 outputs a SWITCH signal and is connected with the base of the switching tube Q3.

[0021] The double-pole double-throw change-over relay K5 outputs a PWM signal and is connected with the emitter of the switching tube Q3.

[0022] Preferably,

[0023] The rectification and boost circuit comprises a diode D1, a diode D2, a capacitor C1, a capacitor C2, a resistor R1 and a resistor R2.

[0024] The anode of the diode D1 is connected with the cathode of the diode D2.

[0025] The cathode of the diode D1 is connected with the anode of the capacitor C1, the resistor R1 and the high common-mode current sampling circuit.

[0026] The anode of the diode D2 is connected with the cathode of the capacitor C2 and the resistor R2.

[0027] The cathode of the capacitor C1 is connected with the anode of the capacitor C2, and the resistor R1 is connected with the resistor R2.

[0028] Preferably,

[0029] The high common-mode current sampling circuit comprises resistors R13, R14, R15, R16, R17, R18, R28 and R29 connected in parallel.

[0030] Preferably,

[0031] The voltage regulating circuit comprises a field effect transistor Q1 and a linear optocoupler U43.

[0032] The high common-mode current sampling circuit, the field effect transistor Q1 and the linear optocoupler U43 are sequentially connected.

[0033] The linear optocoupler U43 is connected with the forward and reverse and current switching circuit and the control unit.

[0034] Preferably,

[0035] The isolation amplification circuit comprises an operational amplifier U15, a linear optocoupler U24 and an operational amplifier U40.

[0036] The high common-mode current sampling circuit, the operational amplifier U15, the linear optocoupler U24, the operational amplifier U40 and the control unit are sequentially connected.

[0037] Preferably,

[0038] The power switch circuit comprises a single-pole switch SW1, a single-pole single-throw normally open relay K4 and a triode Q4.

[0039] The L end of the alternating current input unit is connected with the single-pole switch SW1, and the N end of the alternating current input unit is connected with the single-pole single-throw normally open relay K4.

[0040] The single-pole switch SW1, the single-pole single-throw normally open relay K4, the triode Q4 and the control unit are sequentially connected.

[0041] The utility model has the following beneficial effects:

[0042] Real-time data acquisition is realized through the rectifier and voltage boosting circuit, the high common-mode current sampling circuit, the voltage regulating circuit and the isolation amplification circuit, the working state and performance parameters of the hollow cathode lamp can be acquired in time, the brightness is accurately adjusted according to the working state of the hollow cathode lamp through the control unit, the switching tube Q3 and the forward and reverse and current switching circuit, so that the stable operation and high efficiency output of the light system are ensured, and the double control units are realized through the main and auxiliary board switching circuit, which can work independently or cooperate with other control units. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a structure diagram of the hollow cathode lamp control system of the spectrometer.

[0044] Figure 2 It is a partial principle diagram of the hollow cathode lamp control system of the spectrometer.

[0045] Figure 3 The principle diagram of the main and auxiliary plate switching circuit;

[0046] Figure 4 The principle diagram of the voltage collection circuit;

[0047] Figure 5 The principle diagram of the isolation amplification circuit;

[0048] Figure 6 The principle diagram of the power switch circuit;

[0049] Figure 7 The principle diagram of the interface circuit;

[0050] The realization, functional features and advantages of the utility model will be further explained in combination with embodiments and with reference to the drawings. DETAILED DESCRIPTION

[0051] It should be understood that the specific embodiments described herein are merely intended to explain the utility model, and are not intended to limit the utility model.

[0052] Referring to Figure 1 The utility model provides a hollow cathode lamp control system of spectrometer, include: alternating current input unit, rectification boost circuit, high common mode current sampling circuit, positive and negative and current switching circuit, hollow cathode lamp, switch tube Q3, voltage regulation circuit, control unit, power switch circuit, isolation amplification circuit and interface circuit;

[0053] Alternating current input unit is connected with rectification boost circuit and power switch circuit, and control unit is connected with power switch circuit;

[0054] Rectification boost circuit, high common mode current sampling circuit, voltage regulation circuit, positive and negative and current switching circuit and hollow cathode lamp are connected in proper order;

[0055] Control unit, switch tube Q3 and positive and negative and current switching circuit are connected in proper order;

[0056] Control unit is connected with voltage regulation circuit;

[0057] High common mode current sampling circuit, isolation amplification circuit and control unit are connected in proper order, and control unit is connected with interface circuit.

[0058] Specifically, part principle diagram of hollow cathode lamp control system of spectrometer is as Figure 2 Shown in the drawing;

[0059] The control unit sends an activation signal (total switch) and the system starts to work. The system first boosts and rectifies the 220V AC input to obtain the required positive voltage of the hollow cathode lamp (HCL). The high common-mode current sampling circuit and the isolation amplifier circuit jointly undertake the task of measuring the current output to the HCL. The high common-mode current sampling circuit realizes current monitoring through voltage sampling, and the isolation amplifier circuit converts the obtained digital signal into an analog signal and transmits it to the control unit. The voltage regulating circuit adjusts the output negative voltage of the HCL by adjusting the duty cycle of the pulse width modulation (PWM) signal sent by the control unit. At the same time, the switch signal of the control unit is also used to control the positive and negative switching of the circuit, so that the system can realize the functions of positive processing and negative processing. At the same time, according to whether the main board and the auxiliary board are connected, it is automatically judged whether the hollow cathode lamp control circuit is controlled by the main board controller or the auxiliary board controller. When the control unit stops sending the activation signal (total switch), the system stops working.

[0060] When the control unit outputs the PWM signal to the system, the indicator LED2 lights up, indicating the presence of the PWM signal. Then, the light-emitting diode on the original side of the linear optocoupler is turned on and emits light, activating the photosensitive triode in the linear optocoupler. At this time, the output voltage of the linear optocoupler is divided by the resistor and transmitted to the gate of the switch tube, so that the voltage between the gate and the source of the switch tube reaches the conduction condition. Therefore, the negative high voltage V- obtained by the system from the boost rectifier is transmitted to the pin 1 and pin 8 of the double-pole double-throw switch through the switch tube. The voltage of pin 1 is transmitted to the pin 1 of the HCL through pin 9. At this time, if the hollow cathode lamp positive and negative switch is set to "positive" position, the current is kept below 10mA, realizing the function of negative processing.

[0061] In this system, the control unit adjusts the duty cycle of the PWM signal, which in turn changes the on-off time of the linear optocoupler, resulting in a corresponding change in the on-off time of the switch tube, thereby adjusting the average value of V- voltage in a period, realizing the function of voltage regulation. In order to realize this function, the system uses a high common-mode current sampling circuit and an isolation amplifier circuit to transmit the current signal to the control unit for monitoring, and feeds back the monitoring results to the upper computer and the touch screen.

[0062] To ensure the system safety, the SWITCH conversion must be carried out when the PWM duty cycle is 0. Therefore, when the control unit outputs PWM signal with duty cycle 0, the Switch signal can be generated to carry out circuit switching. Once the control unit outputs Switch signal, the switch tube Q3 will be turned on, and the double-pole double-throw change-over relay K1 and the single-pole single-throw change-over relay K2 will also be turned on. The turn-on of the single-pole single-throw change-over relay K2 will cause R15, R16, R17, R18, R28, R29 to be in parallel with R13, R14, reduce the overall resistance value, reduce the voltage drop of the parallel resistance, so that the forward large voltage passes through the parallel resistance and is delivered to the pin 4 and pin 5 of the double-pole double-throw switch. At the same time, with the reduction of resistance, the current increases, and the current is between 25mA and 30mA and is delivered to the HCL. The turn-on of the double-pole double-throw change-over relay K1 will cause the pin 8 and pin 12 of the double-pole double-throw switch to be connected, and the pin 5 and pin 9 to be connected. The voltage V- is delivered to the pin 2 of the HCL through the pin 12, and the positive voltage is delivered to the pin 1 of the HCL through the pin 9, so that the forward and reverse switches are in the "reverse" state, and the current is between 25mA and 30mA, thereby realizing the function of forward aging.

[0063] In addition, the two pins of the HCL are also connected with a compensation capacitor U17, which adjusts the reactive power to stabilize the voltage and prevent the HCL from oscillating.

[0064] As an embodiment, the forward and reverse and current switching circuit refers to Figure 2 :

[0065] The forward and reverse and current switching circuit comprises a single-pole single-throw change-over relay K2 and a double-pole double-throw change-over relay K1.

[0066] The high common-mode current sampling circuit, the single-pole single-throw change-over relay K2, the double-pole double-throw change-over relay K1 and the hollow cathode lamp are sequentially connected.

[0067] Specifically, the control unit controls the on-off state of the switch tube by sending the Switch signal, and then triggers the double-pole double-throw change-over relay and the single-pole single-throw change-over relay. When the single-pole single-throw change-over relay is triggered, the resistance of the circuit is reduced and the current is increased, thereby realizing the function of the current switching circuit. When the double-pole double-throw change-over relay is triggered, the function of the forward and reverse switching circuit is realized. Through such forward and reverse and current switching circuit, the system can realize the bidirectional processing of the HCL, and has more flexible and efficient characteristics.

[0068] As an embodiment, the control unit refers to Figure 1 :

[0069] The control unit comprises a sub-control board, a main control board and a main-sub board switching circuit.

[0070] The interface circuit is connected with the sub-control board;

[0071] The main-sub board switching circuit is connected with the sub-control board, the main control board, the switch tube Q3, the isolation amplification circuit and the power switch circuit.

[0072] As an embodiment, the main-sub board switching circuit refers to Figure 3 :

[0073] The main-sub board switching circuit comprises a double-pole double-throw change-over relay K3 and a double-pole double-throw change-over relay K5.

[0074] The double-pole double-throw change-over relay K3 outputs a SWITCH signal and is connected with the base of the switch tube Q3.

[0075] The double-pole double-throw change-over relay K5 outputs a PWM signal and is connected with the emitter of the switch tube Q3.

[0076] Specifically, the main-sub board switching circuit aims to realize the automatic switching between the main board and the sub-board through two double-pole double-throw change-over relays. The core goal of this design is to realize the free switching of the double controllers on a set of boards to solve the contradiction in the case of insufficient memory or operation precision of the main board controller. The principle is as follows: when the main board is inserted into the sub-board interface, the diode (D4) is turned on, and the two relays are simultaneously actuated, so that the cathode lamp control circuit of the sub-board is managed by the main board controller, and the sub-board controller is in standby state; when the main board is not inserted into the sub-board interface, the two relays are not actuated, and the system remains in the default state, at this time the cathode lamp control circuit of the sub-board is managed by the sub-board controller. Through this intelligent switching design, flexible application of the main and sub boards is realized, thereby improving the reliability and expandability of the system.

[0077] As an embodiment, the rectifier boost circuit refers to Figure 2 :

[0078] The rectifier boost circuit comprises a diode D1, a diode D2, a capacitor C1, a capacitor C2, a resistor R1 and a resistor R2.

[0079] The anode of the diode D1 is connected with the cathode of the diode D2.

[0080] The cathode of the diode D1 is connected with the anode of the capacitor C1, the resistor R1 and the high common-mode current sampling circuit.

[0081] The anode of the diode D2 is connected with the cathode of the capacitor C2 and the resistor R2.

[0082] The cathode of the capacitor C1 is connected with the anode of the capacitor C2, and the resistor R1 is connected with the resistor R2.

[0083] Specifically, the rectifier boost circuit rectifies the 220V AC voltage input from the live line through two series-connected diodes. Subsequently, energy is stored through capacitors, achieving voltage boosting and filtering. Each capacitor is connected in parallel with a resistor to protect the voltage within a safe range. Finally, through the voltage regulation circuit and forward-reverse switching circuit, the specified voltage can be accurately output. The design of this module aims to provide stable and reliable voltage output to meet the power requirements of various application scenarios.

[0084] At system startup, the live line voltage is converted to DC voltage through diode rectification, and then boosted and filtered through capacitors to obtain the required positive and negative high voltage. The positive high voltage is stepped down through parallel resistors (R13 and R14) and delivered to pins 4 and 5 of the double-pole double-throw switch. The voltage at pin 4 is delivered to pin 2 (HCL+) of the HCL (hollow cathode lamp) via pin 12. At the same time, the current generated by the circuit is delivered to the HCL, and due to the large parallel resistance, the current is maintained below 10mA. The capacitor part is designed with parallel resistors to protect the circuit.

[0085] As an embodiment, the high common-mode current sampling circuit refers to Figure 2 :

[0086] The high common-mode current sampling circuit includes resistors R13, R14, R15, R16, R17, R18, R28, and R29 connected in parallel.

[0087] Specifically, a voltage acquisition circuit is set up to acquire the voltage across resistor R57, which is used to calculate the current value. The voltage acquisition circuit is as shown in Figure 4 The operation steps of the voltage acquisition circuit are as follows: first, the output current of the boost rectifier circuit passes through a resistor, which controls the voltage difference at about 10V. Then, the acquired voltage signal is buffered through two servo amplifiers to ensure that the voltage signal will not be attenuated due to the impedance across the resistor. Finally, the voltage output by the two servo amplifiers is subtracted using a differential amplifier, thereby obtaining the accurate voltage value corresponding to the acquired current value. Through this process, the function of the ammeter is realized, ensuring accurate acquisition and measurement of the feedback current.

[0088] As an embodiment, the voltage regulation circuit refers to Figure 2 :

[0089] The voltage regulation circuit includes a field effect transistor Q1 and a linear optocoupler U43.

[0090] The high common-mode current sampling circuit, the field effect transistor Q1, and the linear optocoupler U43 are connected in sequence.

[0091] Linear optical coupling U43 is connected with forward and reverse and current switching circuit and control unit.

[0092] Specifically, the key of the voltage regulating circuit is that the control unit adjusts the duty cycle of the pulse width modulation (PWM) signal to adjust the output voltage. The PWM signal is used to trigger the conduction of the linear optical coupling. By adjusting the duty cycle of the PWM signal, the conduction time of the linear optical coupling can be accurately controlled, and then the conduction time of the switch tube is controlled, and finally the size of the output to the HCL negative voltage V- is adjusted.

[0093] As an embodiment, the isolation amplification circuit refers to Figure 5

[0094] The isolation amplification circuit comprises an operational amplifier U15, a linear optical coupling U24 and an operational amplifier U40.

[0095] The high common-mode current sampling circuit, the operational amplifier U15, the linear optical coupling U24, the operational amplifier U40 and the control unit are connected in sequence.

[0096] Specifically, the function of the isolation amplification circuit is to detect the high common-mode component of the HCL current and output a digital signal IOUT. In this circuit, to prevent signal attenuation, IOUT is subjected to signal buffering processing by a follower amplifier. Subsequently, through optical coupling isolation technology, the signal is transmitted to a low-power single operational amplifier for voltage amplitude modulation processing. Finally, the processed signal is output to the control unit to realize isolation and protection control of the HCL. This design scheme ensures efficient and reliable monitoring and protection of the HCL, thereby enhancing the stability and safety of the overall system.

[0097] As an embodiment, the power switch circuit refers to Figure 6

[0098] The power switch circuit comprises a single-pole switch SW1, a single-pole single-throw normally open relay K4 and a triode Q4.

[0099] The L terminal of the alternating current input unit is connected with the single-pole switch SW1, and the N terminal of the alternating current input unit is connected with the single-pole single-throw normally open relay K4.

[0100] The single-pole switch SW1, the single-pole single-throw normally open relay K4, the triode Q4 and the control unit are connected in sequence.

[0101] ​​Specifically, the control unit is responsible for outputting an activation signal (ON) to the switch tube, and then turning on the switch tube, triggering the single-pole double-throw normally open relay, so that the live wire and the zero wire in the circuit are connected, and the system obtains power supply and starts to work. When the control unit stops outputting the activation signal (ON), the relay will automatically disconnect, causing the system to stop working. The implementation of the power switch circuit utilizes the precise control unit to ensure that the system can be reliably started and stopped when needed.

[0102] As an embodiment, the interface circuit refers to Figure 7

[0103] The interface circuit covers serial port screen interface circuit and USB host circuit, aiming to realize the electrostatic protection function to prevent static electricity from being generated during manual connection, thereby protecting the controller from damage. The core idea of the design is to meet the interaction between the host computer and the controller to realize precise control of the hollow cathode lamp control system. At the same time, the design of the touch screen also enables users to accurately control the hollow cathode lamp control system without the host computer.

[0104] It should be noted that in this document, the terms "comprise", "comprise", or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent to such a process, method, article or system. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of another identical element in the process, method, article or system including the element.

[0105] The above-mentioned embodiment serial numbers of the utility model are only for description, and do not represent the advantages and disadvantages of the embodiments. In the unit claims of several devices, several of these devices can be embodied by the same hardware item. The use of the words first, second, and third does not represent any order, and these words can be interpreted as identifiers.

[0106] The above is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structure or equivalent process transformation using the contents of the utility model specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection range of the utility model.​

Claims

1. A hollow cathode lamp control system for a spectrometer, characterized in that: include: AC input unit, rectifier boost circuit, high common mode current sampling circuit, forward and reverse and current switching circuit, hollow cathode lamp, switch tube Q3, voltage regulation circuit, control unit, power switch circuit, isolation amplifier circuit and interface circuit; The AC input unit is connected to the rectifier and boost circuit and the power switch circuit, and the control unit is connected to the power switch circuit; The rectifier boost circuit, the high common mode current sampling circuit, the voltage regulating circuit, the forward and reverse and current switching circuits and the hollow cathode lamp are connected in sequence; The control unit, the switch tube Q3 and the forward, reverse and current switching circuits are connected in sequence; The control unit is connected to the voltage regulating circuit; The high common mode current sampling circuit, the isolation amplifier circuit and the control unit are connected in sequence, and the control unit is connected to the interface circuit.

2. The hollow cathode lamp control system of the spectrometer according to claim 1, characterized in that: The forward, reverse and current switching circuit includes: a single-pole single-throw normally open relay K2 and a double-pole double-throw changeover relay K1; The high common mode current sampling circuit, the single-pole single-throw normally open relay K2, the double-pole double-throw changeover relay K1 and the hollow cathode lamp are connected in sequence.

3. The hollow cathode lamp control system of the spectrometer according to claim 1, characterized in that: The control unit includes: a sub-control board, a main control board and a main-sub-board switching circuit; The interface circuit is connected to the auxiliary control board; The main-sub-board switching circuit is connected to the sub-control board, the main control board, the switch tube Q3, the isolation amplifier circuit and the power switch circuit.

4. The hollow cathode lamp control system of the spectrometer according to claim 3, characterized in that: The main and auxiliary board switching circuits include: double-pole double-throw change-over relay K3 and double-pole double-throw change-over relay K5; The double-pole double-throw changeover relay K3 outputs a SWITCH signal and is connected to the base of the switch tube Q3; The double-pole double-throw change-over relay K5 outputs a PWM signal and is connected to the emitter of the switch tube Q3.

5. The hollow cathode lamp control system of the spectrometer according to claim 1, characterized in that: The rectifier and boost circuit includes: a diode D1, a diode D2, a capacitor C1, a capacitor C2, a resistor R1 and a resistor R2; The anode of diode D1 is connected to the cathode of diode D2; The cathode of the diode D1 is connected to the anode of the capacitor C1, the resistor R1 and the high common mode current sampling circuit; The anode of the diode D2 is connected to the cathode of the capacitor C2 and the resistor R2; The negative electrode of the capacitor C1 is connected to the positive electrode of the capacitor C2, and the resistor R1 is connected to the resistor R2.

6. The hollow cathode lamp control system of a spectrometer according to claim 1, characterized in that: The high common-mode current sampling circuit includes a resistor R13 , a resistor R14 , a resistor R15 , a resistor R16 , a resistor R17 , a resistor R18 , a resistor R28 , and a resistor R29 connected in parallel.

7. The hollow cathode lamp control system of a spectrometer according to claim 1, characterized in that: The voltage regulating circuit includes: field effect tube Q1 and linear optocoupler U43; The high common mode current sampling circuit, field effect transistor Q1 and linear optocoupler U43 are connected in sequence; The linear optocoupler U43 is connected to the forward, reverse and current switching circuits and the control unit.

8. The hollow cathode lamp control system of a spectrometer according to claim 1, characterized in that: The isolation amplifier circuit includes: operational amplifier U15, linear optocoupler U24 and operational amplifier U40; The high common-mode current sampling circuit, operational amplifier U15, linear optocoupler U24, operational amplifier U40 and control unit are connected in sequence.

9. The hollow cathode lamp control system of a spectrometer according to claim 1, characterized in that: The power switch circuit includes: a single-throw switch SW1, a single-pole single-throw normally open relay K4 and a transistor Q4; The L terminal of the AC input unit is connected to the single-throw switch SW1, and the N terminal of the AC input unit is connected to the single-pole single-throw normally open relay K4; The single-throw switch SW1, the single-pole single-throw normally-open relay K4, the transistor Q4 and the control unit are connected in sequence.

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