A direct current power supply for mass spectrometry instruments and circuitry therefor

Abstract

The application provides a direct current power supply and a circuit thereof for a mass spectrometry instrument, relates to the field of mass spectrometry, and comprises a negative high-voltage generation channel circuit, a positive high-voltage generation channel circuit and a common-mode offset control circuit; wherein the negative high-voltage generation channel circuit comprises a first operational amplifier, a high-voltage NPN transistor, a high-voltage PNP transistor and a PNP common-base amplifier; the positive high-voltage generation channel circuit comprises a second operational amplifier, a high-voltage NPN transistor, a high-voltage PNP transistor and an NPN common-base amplifier; a common-mode voltage signal output by the common-mode offset control circuit is connected to the negative high-voltage generation channel circuit and the positive high-voltage generation channel circuit respectively, and the negative high-voltage generation channel circuit is connected to the positive high-voltage generation channel circuit. A low-voltage precision operational amplifier is adopted, a level shift and a totem-pole output stage composed of discrete components are combined, and through negative feedback control, stable control of a high-voltage, large-dynamic-range direct current output by a low-voltage and high-precision DAC signal is realized.

Description

Technical Field

[0001] This invention relates to the field of mass spectrometry analysis technology, and more specifically, to a DC power supply and its circuit for a mass spectrometry analysis instrument. Background Technology

[0002] In mass spectrometers, ion optics systems, and high-precision analytical instruments, quadrupole mass analyzers require a highly stable and high-resolution bipolar high-voltage DC power supply (typically ±200V or higher) to establish the necessary electric field shape for efficient ion screening and precise control. Traditional implementations of this type of power supply typically employ the following two technical approaches:

[0003] One approach is to use dedicated high-voltage operational amplifiers (such as APEX's PA series high-voltage op-amps) or modular high-voltage power supply chips. While this approach offers good performance, the components are extremely expensive (for example, a single high-voltage op-amp can cost hundreds of RMB), and it often requires complex peripheral circuitry, resulting in low system integration, high power consumption, and large size.

[0004] The second approach involves power extension stage circuits built using standard operational amplifiers and discrete components, such as complementary symmetric emitter followers (totem-pole structures) or linear voltage regulators with current amplification. While these solutions offer some cost reduction, they generally suffer from low output voltage accuracy, large temperature drift, slow dynamic response, limited load capacity, and insufficient stability under high voltage. Especially in applications requiring 16-bit or higher DAC control, microvolt-level resolution, and fast settling times, existing solutions struggle to achieve a good balance between cost and performance.

[0005] Therefore, there is an urgent need in this field for a DC power supply for mass spectrometry that can simultaneously achieve high precision, high stability, fast response, and low cost under high voltage output conditions. Summary of the Invention

[0006] In view of the problems of high cost, complex circuit, insufficient accuracy, slow dynamic response and poor stability of DC power supply solutions for mass spectrometry, this invention proposes a DC power supply and its circuit for mass spectrometry analysis instruments.

[0007] In a first aspect, embodiments of the present invention provide a DC power supply circuit for a mass spectrometry analyzer, the circuit comprising:

[0008] Negative high voltage generation channel circuit, positive high voltage generation channel circuit, and common mode offset control circuit;

[0009] The negative high voltage generation channel circuit includes a first operational amplifier, a high voltage NPN transistor, a high voltage PNP transistor, and a PNP common-base amplifier.

[0010] The positive high voltage generation channel circuit includes a second operational amplifier, a high-voltage NPN transistor, a high-voltage PNP transistor, and an NPN common-base amplifier;

[0011] The common-mode voltage signal output by the common-mode offset control circuit is connected to the negative high-voltage generation channel circuit and the positive high-voltage generation channel circuit, respectively, and the negative high-voltage generation channel circuit is connected to the positive high-voltage generation channel circuit.

[0012] As one possible implementation, the negative high voltage generation channel circuit and the positive high voltage generation channel circuit are arranged in a mirror image.

[0013] As one possible implementation, the gain of the first operational amplifier is -66.66 times.

[0014] In one possible implementation, in the negative high voltage generation channel circuit, the non-inverting input terminal of the first operational amplifier is connected to the control voltage signal, the inverting input terminal is connected to the common-mode voltage signal, and the output terminal is connected to the base of the high-voltage NPN transistor.

[0015] The emitter of the high-voltage NPN transistor is connected to the high-voltage negative power supply, and the collector is connected to the collector of the high-voltage PNP transistor.

[0016] The emitter of the high-voltage PNP transistor is connected to the high-voltage positive power supply, and the base is connected to the collector of the PNP common-base amplifier.

[0017] The base of the PNP common-base amplifier is connected to a high-voltage negative power supply, and the emitter of the PNP common-base amplifier is connected to the output terminal of the first operational amplifier.

[0018] As one possible implementation, the negative high voltage generation channel circuit further includes:

[0019] The feedback resistor has one end connected to the collector of the high-voltage NPN transistor in the negative high-voltage generation channel circuit, and the other end connected to the non-inverting input of the first operational amplifier.

[0020] In one possible implementation, in the positive high voltage generation channel circuit, the non-inverting input terminal of the second operational amplifier is connected to the negative high voltage generation channel circuit, the inverting input terminal is connected to the common-mode voltage signal, and the output terminal of the second operational amplifier is connected to the emitter of the NPN common-base amplifier.

[0021] The base of the NPN common-base amplifier is connected to a high-voltage negative power supply, and the collector is connected to the base of a high-voltage NPN transistor.

[0022] The emitter of the high-voltage NPN transistor is connected to the high-voltage negative power supply, and the collector is connected to the collector of the high-voltage PNP transistor.

[0023] The base of the high-voltage PNP transistor is connected to the output of the second operational amplifier, and the emitter is connected to the high-voltage positive power supply.

[0024] As one possible implementation, the negative high voltage generation channel circuit further includes:

[0025] A protection diode is connected in parallel to the base and emitter of the high-voltage NPN transistor and / or the base and emitter of the PNP common-base amplifier.

[0026] As one possible implementation, the negative high voltage generation channel circuit further includes: a first RC parallel network and a second RC parallel network;

[0027] In the negative high voltage generation channel circuit, the first RC parallel network is connected in parallel to the base and collector of the high voltage NPN transistor;

[0028] One end of the second RC parallel network is connected to the output of the first operational amplifier, and the other end is connected to the emitter of the PNP common-base amplifier.

[0029] Secondly, embodiments of the present invention provide a DC power supply for a mass spectrometry analyzer, the DC power supply comprising: a chip, the chip comprising the power supply circuit described in the first aspect.

[0030] The embodiments of the present invention provide a DC power supply and circuit for a mass spectrometry analyzer, comprising a negative high-voltage generation channel circuit, a positive high-voltage generation channel circuit, and a common-mode offset control circuit; wherein, the negative high-voltage generation channel circuit comprises a first operational amplifier, a high-voltage NPN transistor, a high-voltage PNP transistor, and a PNP common-base amplifier; the positive high-voltage generation channel circuit comprises a second operational amplifier, a high-voltage NPN transistor, a high-voltage PNP transistor, and an NPN common-base amplifier; the common-mode voltage signal output by the common-mode offset control circuit is connected to the negative high-voltage generation channel circuit and the positive high-voltage generation channel circuit, respectively, and the negative high-voltage generation channel circuit is connected to the positive high-voltage generation channel circuit.

[0031] In this way, by using a low-voltage precision operational amplifier, combined with a level shifter and totem-pole output stage composed of discrete components, and through precise negative feedback control, stable, accurate and fast control of high-voltage, wide dynamic range DC output using low-voltage, high-precision DAC signals is achieved. Attached Figure Description

[0032] Figure 1This is a DC power supply circuit diagram for a mass spectrometry analyzer, according to an embodiment of the present invention. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] Figure 1 A DC power supply circuit for a mass spectrometry analyzer to which the present invention can be applied is shown, comprising: a negative high voltage generation channel circuit, a positive high voltage generation channel circuit, and a common-mode offset control circuit.

[0036] The negative high voltage generation channel circuit includes a first operational amplifier U1.1, a high-voltage NPN transistor Q1, a high-voltage PNP transistor Q5, and a PNP common-base amplifier Q4.

[0037] Among them, the non-inverting input of the first operational amplifier U1.1 is connected to the control voltage signal DC_CTL output of the 16-bit DAC, the inverting input is connected to the common-mode voltage signal VCM, and the output is connected to the base of the high-voltage NPN transistor Q1.

[0038] The emitter of the high-voltage NPN transistor Q1 is connected to the high-voltage positive power supply VDD2, and the collector is connected to the collector of the high-voltage PNP transistor Q5.

[0039] The emitter of the high-voltage PNP transistor Q5 is connected to the high-voltage negative power supply VEE1, and the base is connected to the collector of the PNP common-base amplifier Q4.

[0040] The base of the PNP common-base amplifier Q4 is connected to the high-voltage negative power supply VEE, and the emitter is connected to the output terminal of the first operational amplifier U1.1.

[0041] Thus, the output of the first operational amplifier U1.1 drives the base of the upper transistor of the high-voltage totem-pole output stage, namely the high-voltage NPN transistor Q1, through a voltage divider network formed by resistors R3 and R4. The base control signal of the lower transistor of the totem-pole output stage, namely the high-voltage PNP transistor Q5, is converted into a Cascode level shift circuit through the PNP common-base amplifier Q4. This Cascode circuit shifts the low-voltage control signal, which is referenced to ground, to a high-voltage domain, which is referenced to -500V to 0V, thereby ensuring that the high-voltage PNP transistor Q5 is precisely driven within its safe operating range.

[0042] Optionally, the negative high voltage generation channel circuit further includes:

[0043] The feedback resistor R7, with one end connected to the collector of the high-voltage NPN transistor Q1 and the other end connected to the non-inverting input of the first operational amplifier U1.1, forms a closed loop. This loop is crucial for stabilizing the output voltage, accurately setting the gain, and suppressing errors. In this way, the gain of the first operational amplifier U1.1 can be precisely set to -66.66 times by the feedback network. This high gain amplifies the DAC signal to the required high-voltage range.

[0044] Optionally, the negative high voltage generation channel circuit further includes:

[0045] Protection diodes D1 and D3 are used to ensure the safe operation of transistors and suppress voltage spikes.

[0046] The protection diode D1 is connected in parallel to the base and emitter of the high-voltage NPN transistor Q1, and the protection diode D3 is connected in parallel to the base and emitter of the PNP common-base amplifier Q4.

[0047] Optionally, the negative high voltage generation channel circuit further includes:

[0048] The system comprises a first RC parallel network, a second RC parallel network, and a third RC parallel network. The first RC parallel network includes a resistor R5 and a capacitor C1 connected in parallel; the second RC parallel network includes a resistor R16 and a capacitor C5 connected in parallel; and the third RC parallel network includes a capacitor C2 and a feedback resistor R7 connected in parallel. The first RC parallel network is connected in parallel to the base and collector of the high-voltage NPN transistor Q1. One end of the second RC parallel network is connected to the output of the first operational amplifier U1.1, and the other end is connected to the emitter of the PNP common-base amplifier Q4. The third RC parallel network is connected in series between the output of the first operational amplifier and the base of the high-voltage NPN transistor Q1.

[0049] Optionally, the negative high voltage generation channel circuit further includes: resistors R6, R3, R4, R11, R17, R20, and R21.

[0050] In this configuration, resistor R6 is connected in series between the non-inverting input of the first operational amplifier U1.1 and the control voltage signal DC_CTL output by the 16-bit DAC. Resistor R3 is connected in series between the base of the high-voltage NPN transistor Q1 and the high-voltage positive power supply VDD2. Resistor R4 is connected in series between the emitter of the high-voltage NPN transistor Q1 and the high-voltage positive power supply VDD2. Resistor R11 is connected in series between the inverting input of the first operational amplifier U1.1 and the common-mode voltage signal VCM. Resistor R17 is connected in series between the inverting input of the first operational amplifier U1.1 and the ground terminal. Resistor R20 is connected in series between the collector of the PNP common-base amplifier Q4 and the high-voltage negative power supply VEE1, and resistor R21 is connected in series between the high-voltage PNP transistor Q5 and the high-voltage negative power supply VEE1.

[0051] Optionally, the negative high voltage generation channel circuit further includes: capacitor C4, capacitor C6, and capacitor C7.

[0052] Among them, capacitors C4 and C6 are connected in series between the power supply and ground of the first operational amplifier U1.1, respectively, to filter out high-frequency noise and interference signals in the power supply; capacitor C7 is connected in parallel between the output terminal and the inverting input terminal of the first operational amplifier U1.1.

[0053] The positive high voltage generation channel circuit includes a second operational amplifier U1.2, a high-voltage PNP transistor Q6, a high-voltage NPN transistor Q2, and an NPN common-base amplifier Q3.

[0054] Among them, the non-inverting input terminal of the second operational amplifier U1.2 is connected to the collector of the high-voltage NPN transistor Q1 in the negative high-voltage generation channel circuit, the inverting input terminal is connected to the common-mode voltage signal VCM, and the output terminal is connected to the emitter of the NPN common-base amplifier Q3.

[0055] The base of the NPN common-base amplifier Q3 is connected to the high-voltage positive power supply VDD2, and the collector is connected to the base of the high-voltage NPN transistor Q2.

[0056] The emitter of the high-voltage NPN transistor Q2 is connected to the high-voltage positive power supply VDD1, and the collector is connected to the collector of the high-voltage PNP transistor Q6.

[0057] The base of the high-voltage PNP transistor Q6 is connected to the output terminal of the second operational amplifier U1.2, and the emitter of the high-voltage PNP transistor Q6 is connected to the high-voltage negative power supply VEE.

[0058] The positive high-voltage channel serves as a mirror image of the negative high-voltage channel, with its reference obtained from the negative channel through a high-precision (0.1%) 1,000 MΩ resistor divider. The output of the second operational amplifier U1.2 is connected to an NPN common-base amplifier Q3, forming a Cascode level shift circuit to boost the voltage level, shifting it from the low-voltage domain to the high-voltage domain with a reference of 0V to +500V, thereby controlling the operation of the positive high-voltage totem-pole output stage.

[0059] Optionally, the positive high voltage generation channel circuit further includes:

[0060] Protection diodes D2 and D4 are used to ensure the safe operation of transistors and suppress voltage spikes.

[0061] The protection diode D2 is connected in parallel to the base and emitter of the NPN common-base amplifier Q3, and one end of the protection diode D4 is connected to the base of the high-voltage NPN transistor Q6, and the other end is connected to the high-voltage negative power supply VEE.

[0062] Optionally, the positive high voltage generation channel circuit further includes:

[0063] The fourth RC parallel network and the fifth RC parallel network, wherein the fourth RC parallel network includes a resistor R8 and a capacitor C3 connected in parallel, and the fifth RC parallel network includes a resistor R19 and a capacitor C11 connected in parallel.

[0064] The fourth RC parallel network is connected in series between the emitter of the NPN common-base amplifier Q3 and the output of the second operational amplifier U1.2, and the fifth RC parallel network is connected in series between the base of the high-voltage NPN transistor Q6 and the output of the second operational amplifier U1.2.

[0065] Optionally, the negative high voltage generation channel circuit further includes: resistors R12, R18, R1, R2, R22, and R23.

[0066] One end of resistor R12 is connected to the collector of the high-voltage PNP transistor Q5, and the other end is connected to the non-inverting input of the second operational amplifier U1.2. Resistor R18 is connected in series between the common-mode voltage signal VCM and the unidirectional output of the non-inverting input of the second operational amplifier U1.2. Resistor R1 is connected in series between the base of the high-voltage PNP transistor Q2 and the high-voltage positive power supply VDD1. Resistor R2 is connected in series between the emitter of the high-voltage PNP transistor Q2 and the high-voltage positive power supply VDD1. Resistor R22 is connected in series between the base of the high-voltage NPN transistor Q6 and the high-voltage negative power supply VEE. Resistor R23 is connected in series between the emitter of the high-voltage NPN transistor Q6 and the high-voltage negative power supply VEE.

[0067] The common-mode offset control circuit includes terminals j1, j2, j3, and j4, resistors R13, R9, R10, R14, and R15, and capacitors C8, C9, C10, and C11.

[0068] Among them, terminal j1 is connected to the control voltage signal DC_CTL, terminal j2 is connected to C11 in series and then grounded, terminal j3 is connected to C10 in series and then grounded, terminal j4 is connected to the common mode voltage signal VCM, resistors R9 and R10 are connected in series between terminal j2 and the collector of high-voltage NPN transistor Q1, resistors R13, R14 and R15 are connected in series between terminal j3 and the collector of high-voltage NPN transistor Q1, one end of capacitor C8 is connected between resistors R14 and R15 and the other end is grounded, and one end of capacitor C9 is connected between resistors R9 and R10 and the other end is grounded.

[0069] In this way, the common-mode voltage signal VCM of the 12-bit DAC output is simultaneously applied to the setpoints of the positive and negative high-voltage channels. This design allows for a uniform shift (common-mode regulation) of the bipolar output voltage in the same direction without changing the differential-mode voltage between the two outputs.

[0070] In summary, the technical solution of the present invention has the following significant advantages:

[0071] Extremely low cost: By using general-purpose low-voltage operational amplifiers and discrete components to replace expensive high-voltage dedicated chips, the cost of the core circuit can be reduced by more than 60%.

[0072] Extremely high precision: With 16-bit DAC control and deep negative feedback, the output voltage resolution can reach 4.6 mV, with good stability, meeting the extremely high precision requirements of mass spectrometers.

[0073] Strong anti-interference capability: The output filtering design can effectively suppress the coupling of radio frequency (RF) noise and ensure the purity of the output.

[0074] High reliability: The circuit structure is simple, based on mature and general-purpose components, and the system has a long mean time between failures (MTBF).

[0075] Flexible adjustment: Supports common mode offset adjustment function, which facilitates fine optimization of the quadrupole operating point.

[0076] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-disclosed concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. A DC power supply circuit for a mass spectrometry analyzer, characterized in that, include: Negative high voltage generation channel circuit, positive high voltage generation channel circuit, and common mode offset control circuit; The negative high voltage generation channel circuit includes a first operational amplifier, a first high voltage NPN transistor, a first high voltage PNP transistor, an NPN common base amplifier, and a feedback resistor. One end of the feedback resistor is connected to the collector of the first high voltage NPN transistor in the negative high voltage generation channel circuit, and the other end is connected to the non-inverting input terminal of the first operational amplifier. In the negative high voltage generation channel circuit, the non-inverting input terminal of the first operational amplifier is connected to the control voltage signal, the inverting input terminal is connected to the common-mode voltage signal, and the output terminal is connected to the base of the first high voltage NPN transistor. The emitter of the first high-voltage NPN transistor is connected to the second high-voltage positive power supply, and the collector is connected to the collector of the first high-voltage PNP transistor. The emitter of the first high-voltage PNP transistor is connected to the first high-voltage negative power supply, and the base is connected to the collector of the NPN common-base amplifier. The base of the NPN common-base amplifier is connected to the second high-voltage negative power supply, and the emitter of the NPN common-base amplifier is connected to the output terminal of the first operational amplifier. The positive high voltage generation channel circuit includes a second operational amplifier, a second high voltage NPN transistor, a second high voltage PNP transistor, and a PNP common-base amplifier; In the positive high voltage generation channel circuit, the non-inverting input terminal of the second operational amplifier is connected to the negative high voltage generation channel circuit, the inverting input terminal is connected to the common-mode voltage signal, and the output terminal of the second operational amplifier is connected to the emitter of the PNP common-base amplifier. The base of the PNP common-base amplifier is connected to the second high-voltage positive power supply, and the collector is connected to the base of the second high-voltage NPN transistor. The emitter of the second high-voltage NPN transistor is connected to the first high-voltage positive power supply, and the collector is connected to the collector of the second high-voltage PNP transistor. The base of the second high-voltage PNP transistor is connected to the output of the second operational amplifier, and the emitter is connected to the second high-voltage negative power supply. The common-mode voltage signal output by the common-mode offset control circuit is connected to the negative high-voltage generation channel circuit and the positive high-voltage generation channel circuit, respectively, and the negative high-voltage generation channel circuit is connected to the positive high-voltage generation channel circuit. The common-mode voltage signal is connected to the inverting input of the first operational amplifier, and the non-inverting input of the second operational amplifier is connected to the collector of the first high-voltage NPN transistor in the negative high-voltage generation channel circuit, while the inverting input is connected to the common-mode voltage signal.

2. The circuit according to claim 1, characterized in that, The negative high voltage generation channel circuit and the positive high voltage generation channel circuit are arranged in a mirror image.

3. The circuit according to claim 1, characterized in that, The gain of the first operational amplifier is -66.

66.

4. The circuit according to claim 1, characterized in that, The negative high voltage generation channel circuit also includes: A protection diode is connected in parallel to the base and emitter of the first high-voltage NPN transistor and / or the base and emitter of the NPN common-base amplifier.

5. The circuit according to claim 1, characterized in that, The negative high voltage generation channel circuit also includes: a first RC parallel network and a second RC parallel network; In the negative high voltage generation channel circuit, one end of the first RC parallel network is connected to the base of the first high voltage NPN transistor, and the other end is connected to the output of the first operational amplifier. One end of the second RC parallel network is connected to the output of the first operational amplifier, and the other end is connected to the emitter of the NPN common-base amplifier.

6. A DC power supply for a mass spectrometry analyzer, characterized in that, The chip includes a power supply circuit according to any one of claims 1 to 5.

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