Low-power-consumption active driving pulse power supply suitable for time-of-flight mass spectrometer

Abstract

The invention discloses a low-power-consumption active driving pulse power supply suitable for a time-of-flight mass spectrometer. The low-power-consumption active driving pulse power supply comprises an isolation power supply, a delay unit, a transformer unit, a high-speed optocoupler, a first gate driving unit, a second gate driving unit, a first IGBT unit and a second IGBT unit, after an original pulse signal is input into the delay unit, a first delay pulse signal and a second delay pulse signal are output to the first gate driving unit and the second gate driving unit; the transformer unit is connected between the first gate driving unit and the first IGBT unit; the high-speed optocoupler is connected between the second gate driving unit and the second IGBT unit, and the isolation power supply is connected with the high-speed optocoupler; a collector electrode of the first IGBT unit is connected with high voltage HV, and an emitter electrode is used as a pulse voltage output end; the emitter of the second IGBT unit is connected with a bias voltage, and the collector of the second IGBT unit is connected with the emitter of the first IGBT unit through a resistor R6. According to the invention, a stable rising edge and a stable high-voltage pulse voltage can be output.

Description

Technical Field

[0001] The invention relates to the field of pulse power supplies, in particular to a low-power active drive pulse power supply suitable for a time-of-flight mass spectrometer. Background Art

[0002] The high-voltage pulse power supply suitable for time-of-flight mass spectrometers mainly requires a stable output level, a pulse rise edge as short as possible, preferably less than 50ns, and even 20ns, and a pulse frequency of 1 to 20kHz. Common high-voltage pulse power supplies cannot meet the stringent requirements of time-of-flight mass spectrometers because of their poor voltage stability, difficulty in adjusting pulse amplitude, frequency, and duty cycle, and long pulse rise edge time.

[0003] The high-voltage pulse power supply adopts a technology that controls the high voltage output of high-voltage pulses through energy coupling of low-voltage pulse signals. The signal coupled to the high-voltage side usually drives the IGBT in two ways, active and passive, so that the high voltage is output according to the control timing. During the state switching process of the IGBT, a large voltage mutation will be generated at the IGBT emitter. Due to the parasitic capacitance between the collector and the gate, the capacitive coupling between the gate and the collector will produce an oscillating voltage that damages the IGBT oxide layer. This oscillating voltage will also cause the connected IGBT to "turn on by mistake", so this voltage mutation will affect the two connected IGBTs. The tail current in the shutdown process seriously affects the shutdown loss. Even if the gate gives a shutdown signal, the IGBT cannot be completely shut down in time. This is worth noting. When designing the driver, it is necessary to ensure that the driving waveforms of the two IGBTs have enough dead zones. Summary of the invention

[0004] The main purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a low-power active drive pulse power supply suitable for a time-of-flight mass spectrometer, which can output a stable rising edge and a smooth high-voltage pulse voltage.

[0005] The present invention adopts the following technical solution:

[0006] A low-power active drive pulse power supply suitable for a time-of-flight mass spectrometer comprises an isolated power supply, a delay unit, a first gate drive unit, a second gate drive unit, a first IGBT unit and a second IGBT unit; the input end of the delay unit inputs an original pulse signal, and the output end outputs a first delayed pulse signal and a second delayed pulse signal to the first gate drive unit and the second gate drive unit respectively; it is characterized in that it also comprises a transformer unit and a high-speed optocoupler; the input end of the transformer unit is connected to the first gate drive unit, and the output end is connected to the gate of the first IGBT unit, so as to realize passive drive; the input side of the high-speed optocoupler is connected to the second gate drive unit, and the output side of the high-speed optocoupler is connected to the gate of the second IGBT unit, and the isolated power supply is connected to the high-speed optocoupler to provide an isolated power supply, so as to realize active drive; the collector of the first IGBT unit is connected to a high voltage HV through a resistor R4, and the emitter of the first IGBT unit is used as a pulse voltage output end; the emitter of the second IGBT unit is connected to a bias voltage, and the collector of the second IGBT unit is connected to the emitter of the first IGBT unit through a resistor R6.

[0007] The first delayed pulse signal and the second delayed pulse signal drive the transformer and the high-speed optocoupler respectively through the first gate driving unit and the second gate driving unit; the frequencies of the first delayed pulse signal and the second delayed pulse signal are consistent and there is a timing interval, i.e., a dead time, between the timings, and the dead time is controlled by adjusting the resistance of the delay unit.

[0008] The transformer unit includes a resistor R1, a transformer T1, a capacitor C1 and a field effect transistor Q1; one end of the resistor R1 is connected to the first gate driving unit, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the input side of the transformer T1; the field effect transistor Q1 is connected to the output side of the transformer T1 and the first IGBT unit.

[0009] The first IGBT unit includes a Schottky diode D1, a resistor R2, a resistor R3 and a first IGBT tube Q2; one end of the Schottky diode D1 is connected to one end of the resistor R2, and the other end of the Schottky diode D1 is connected to the emitter of the first IGBT tube Q2; the other end of the resistor R2 is connected to one end of the resistor R3 and the gate of the first IGBT tube Q2, and the other end of the resistor R3 is connected to the emitter of the first IGBT tube Q2; the collector of the first IGBT tube Q2 is connected to the resistor R4.

[0010] The second IGBT unit includes a protection tube Z1, a resistor R7, a resistor R8 and a second IGBT tube Q3; one end of the resistor R7 is connected to the high-speed optocoupler, and the other end of the resistor R7 is connected to the gate of the second IGBT tube Q3, one end of the protection tube Z1 and one end of the resistor R8 are respectively connected to the gate of the second IGBT tube Q3, and the other end of the protection tube Z1, the other end of the resistor R8 and the emitter of the second IGBT tube Q3 are connected to the bias voltage; the collector of the second IGBT tube Q3 is connected to the resistor R6.

[0011] The emitter of the first IGBT unit is connected to one end of a resistor R5 , and a resistor R9 is connected between the other end of the resistor R5 and the emitter of the second IGBT unit.

[0012] The isolated power supply adopts an isolated through-hole DC / DC converter TMV 2-2415DHI to provide isolated power.

[0013] The first gate driving unit adopts a MOSFET driving chip COS4427SR, and the second gate driving unit adopts a MOSFET driving chip COS4427SR.

[0014] The delay unit is a circuit unit composed of a plurality of monostable multivibrators SN74LS221DR.

[0015] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention performs energy coupling by means of strong and weak electrical isolation of high-speed photoelectric coupling, and adopts an isolated power supply to drive the first IGBT unit and the second IGBT unit. Such a pulse can more fully control the conduction of the IGBT, thereby making the rising edge of the output high-voltage pulse fast and the low level stable.

[0017] The pulse of the present invention is driven in a variety of ways, using an active way to fully turn on the IGBT to release the charge, and using a passive way to quickly charge the load capacitor. Compared with the active drive method alone, the power consumption of the pulse power supply is reduced, and the power consumption of the first IGBT unit can be reduced while fully releasing the charge of the load capacitor.

[0018] In the present invention, a bidirectional electrostatic and surge protection tube Z1 is provided in the second IGBT unit for clamping, and resistors R3 and R8 are provided in the first IGBT unit and the second IGBT unit, respectively, to enable the input capacitors of the first IGBT tube Q2 and the second IGBT tube Q3 to release charge during level conversion, and resistors R2 and R7 are used to prevent overcurrent and suppress gate oscillation voltage from damaging the IGBT tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a circuit diagram of the present invention;

[0020] Figure 2 This is the circuit structure schematic diagram of the isolated power supply;

[0021] Figure 3 This is the pulse waveform diagram when no load;

[0022] Figure 4 This is the waveform of the rising edge of the pulse when no load;

[0023] Figure 5 It is the waveform of the rising edge of the pulse under load.

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0025] The present invention is further described below through specific implementation modes.

[0026] See also Figure 1 , a low-power active drive pulse power supply suitable for a time-of-flight mass spectrometer, including an isolated power supply, a transformer unit, a high-speed optocoupler, a delay unit, a first gate drive unit, a second gate drive unit, a first IGBT unit, and a second IGBT unit. The input end of the delay unit inputs the original pulse signal, and the output end outputs the first delayed pulse signal and the second delayed pulse signal respectively. The first delayed pulse signal and the second delayed pulse signal are respectively input into the first gate drive unit and the second gate drive unit; the input end of the transformer unit is connected to the first gate drive unit, and the output end is connected to the gate of the first IGBT unit, which is used to realize passive drive of the first IGBT unit. The input side of the high-speed optocoupler is connected to the second gate drive unit, and the output side of the high-speed optocoupler is connected to the gate of the second IGBT unit. The isolated power supply provides an isolation voltage for the high-speed optocoupler, thereby realizing active drive. The collector of the first IGBT unit is connected to the high voltage HV through a resistor R4, and the emitter of the first IGBT unit is used as a pulse voltage output end; the emitter of the second IGBT unit is connected to the bias voltage, and the collector of the second IGBT unit is connected to the emitter of the first IGBT unit through a resistor R6.

[0027] The present invention adopts a passive drive and active drive composite circuit structure, which can fully release the load capacitor charge connected to the pulse voltage output end and reduce the power consumption of the first IGBT unit, compared with the increase of pulse power consumption caused by driving IGBT by active drive. If the residual charge of the load capacitor is not released, the output pulse voltage will be unstable.

[0028] In this embodiment, a delay unit is introduced to prevent the first IGBT unit connected to the high voltage and the second IGBT unit connected to the bias voltage from being turned on at the same time. The first delayed pulse signal and the second delayed pulse signal output by the delay unit drive the transformer T1 and the high-speed optocoupler through the first gate drive unit and the second gate drive unit respectively.

[0029] The first delayed pulse signal and the second delayed pulse signal output by the delay unit are set to have the same frequency. The frequency consistency is to make the output pulse have a stable frequency, duty cycle, and rise time. The first delayed pulse signal and the second delayed pulse signal are both periodic signals with the same frequency, the same voltage amplitude, and different duty cycles. It is set so that within the same period, there is a difference in time between the high levels of the first delayed pulse signal and the second delayed pulse signal. This time difference is the dead time; the dead time is to avoid the first IGBT unit and the second IGBT unit from interfering with each other due to the parasitic inductance and parasitic capacitance between the two, resulting in malfunction of the IGBT tube. The dead time is controlled by adjusting the resistance of the delay unit. The pulse width of the first delayed pulse signal and the second delayed pulse signal is stable and can be controlled by adjusting the resistance of the delay unit.

[0030] The delay unit is a circuit unit composed of multiple monostable multivibrators SN74LS221DR, which is used to generate a first delayed pulse signal and a second delayed pulse signal. The delay unit uses L7805ABD2T-TR to convert 24V voltage into 5V for power supply; the dead time is determined by the resistance and capacitance values ​​connected to the specific pins of the monostable multivibrator SN74LS221DR. By adjusting the resistance and capacitance, there is a time delay between the output signals.

[0031] The first gate drive unit uses a MOSFET drive chip COS4427SR, and the second gate drive unit uses a MOSFET drive chip COS4427SR. The gate drive unit uses a 24V voltage to power it.

[0032] The transformer unit includes a resistor R1, a transformer T1, a capacitor C1, and a field effect transistor Q1. One end of the resistor R1 is connected to the first gate drive unit, and the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the input side of the transformer T1. The transformer realizes the isolation of strong and weak electricity between low voltage and high voltage on the one hand, and realizes the transmission of pulse control signals on the other hand. The field effect transistor Q1 connects the output side of the transformer T1 and the first IGBT unit. The field effect transistor Q1 controls the voltage between the gate and the emitter in the first IGBT unit according to the timing of the pulse. The field effect transistor Q1 can adopt IRFD120PBF. The resistor R1 connected to the first gate drive unit takes a smaller value, and the capacitor C1 takes a value not exceeding 33nF.

[0033] The first IGBT unit includes a Schottky diode D1, a resistor R2, a resistor R3 and a first IGBT tube Q2; one end of the Schottky diode D1 is connected to one end of the resistor R2, and the other end of the Schottky diode D1 is connected to the emitter of the first IGBT tube Q2; the other end of the resistor R2 is connected to one end of the resistor R3 and the gate of the first IGBT tube Q2, and the other end of the resistor R3 is connected to the emitter of the first IGBT tube Q2; the collector of the first IGBT tube Q2 is connected to the resistor R4.

[0034] The second IGBT unit includes a protection tube Z1, a resistor R7, a resistor R8 and a second IGBT tube Q3; one end of the resistor R7 is connected to a high-speed optical coupler, the other end of the resistor R7 is connected to the gate of the second IGBT tube Q3, one end of the protection tube Z1 and one end of the resistor R8 are respectively connected to the gate of the second IGBT tube Q3, the other end of the protection tube Z1, the other end of the resistor R8 and the emitter of the second IGBT tube are connected to the bias voltage; the collector of the second IGBT tube Q3 is connected to the resistor R6. The emitter of the first IGBT unit is connected to one end of the resistor R5, and a resistor R9 is connected between the other end of the resistor R5 and the emitter of the second IGBT unit.

[0035] In this embodiment, the high-speed optocoupler is a gate driver chip VOW3120, which transmits signals between low-voltage circuits and high-voltage circuits. The isolated power supply is connected to the power supply terminal of the high-speed optocoupler to provide an isolated voltage for the high-speed optocoupler. Figure 2 , the isolated power supply is an isolated through-hole DC / DC converter TMV 2-2415DHI, which provides +15V and -15V voltages.

[0036] In this embodiment, the protection tube Z1 is a bidirectional electrostatic and surge protection tube for clamping, the resistor R3 and the resistor R8 are respectively used to release the charge of the input capacitor of the first IGBT tube Q2 and the second IGBT tube Q3 during the level conversion, and the resistor R2 and the resistor R7 are used to prevent overcurrent and suppress the gate oscillation voltage from damaging the IGBT tube. Figure 1 PGND1 is the isolated ground potential of the second IGBT tube Q3, and REF is the bias voltage, which is also the reference low potential of the pulse output.

[0037] Figure 3 Under no-load condition, the high-voltage pulse output is 10kHz in frequency, 500V in high voltage and 0V in bias voltage. Figure 4 is the rising edge of the pulse, the rise time is 15.2ns, Figure 5 After the load is added, the rising edge of the pulse has a rise time of 32.00ns, which meets the requirements of the pulse power supply for the time-of-flight mass spectrometer for the rising edge.

[0038] In the present invention, the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. In the description, the directions or positional relationships indicated by "upper", "lower", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and are not intended to indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] In addition, in the description of this application, unless otherwise specified, "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0040] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer, comprising an isolated power supply, a delay unit, a first gate driving unit, a second gate driving unit, a first IGBT unit and a second IGBT unit; the delay unit inputs an original pulse signal at its input end, and outputs a first delayed pulse signal and a second delayed pulse signal to the first gate driving unit and the second gate driving unit respectively at its output end; characterized in that, It also includes a transformer unit and a high-speed optocoupler; the input end of the transformer unit is connected to the first gate drive unit, and the output end is connected to the gate of the first IGBT unit, so as to realize passive drive; the input side of the high-speed optocoupler is connected to the second gate drive unit, and the output side of the high-speed optocoupler is connected to the gate of the second IGBT unit, and the isolated power supply is connected to the high-speed optocoupler to provide an isolated power supply, so as to realize active drive; the collector of the first IGBT unit is connected to the high voltage HV through the resistor R4, and the emitter of the first IGBT unit is used as the pulse voltage output end; the emitter of the second IGBT unit is connected to the bias voltage, and the collector of the second IGBT unit is connected to the emitter of the first IGBT unit through the resistor R6.

2. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 1, characterized in that: The first delayed pulse signal and the second delayed pulse signal drive the transformer and the high-speed optocoupler respectively through the first gate driving unit and the second gate driving unit; the frequencies of the first delayed pulse signal and the second delayed pulse signal are consistent and there is a timing interval, i.e., a dead time, between the timings, and the dead time is controlled by adjusting the resistance of the delay unit.

3. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 1, characterized in that: The transformer unit includes a resistor R1, a transformer T1, a capacitor C1 and a field effect transistor Q1; one end of the resistor R1 is connected to the first gate driving unit, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the input side of the transformer T1; the field effect transistor Q1 is connected to the output side of the transformer T1 and the first IGBT unit.

4. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 3, characterized in that: The first IGBT unit includes a Schottky diode D1, a resistor R2, a resistor R3 and a first IGBT tube Q2; one end of the Schottky diode D1 is connected to one end of the resistor R2, and the other end of the Schottky diode D1 is connected to the emitter of the first IGBT tube Q2; the other end of the resistor R2 is connected to one end of the resistor R3 and the gate of the first IGBT tube Q2, and the other end of the resistor R3 is connected to the emitter of the first IGBT tube Q2; the collector of the first IGBT tube Q2 is connected to the resistor R4.

5. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 1, characterized in that: The second IGBT unit includes a protection tube Z1, a resistor R7, a resistor R8 and a second IGBT tube Q3; one end of the resistor R7 is connected to the high-speed optocoupler, and the other end of the resistor R7 is connected to the gate of the second IGBT tube Q3, one end of the protection tube Z1 and one end of the resistor R8 are respectively connected to the gate of the second IGBT tube Q3, and the other end of the protection tube Z1, the other end of the resistor R8 and the emitter of the second IGBT tube Q3 are connected to the bias voltage; the collector of the second IGBT tube Q3 is connected to the resistor R6.

6. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 1, characterized in that: The emitter of the first IGBT unit is connected to one end of a resistor R5 , and a resistor R9 is connected between the other end of the resistor R5 and the emitter of the second IGBT unit.

7. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 1, characterized in that: The isolated power supply adopts an isolated through-hole DC / DC converter TMV 2-2415DHI to provide isolated power.

8. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 1, characterized in that: The first gate driving unit adopts a MOSFET driving chip COS4427SR, and the second gate driving unit adopts a MOSFET driving chip COS4427SR.

9. A low-power active driving pulse power supply suitable for a time-of-flight mass spectrometer as claimed in claim 1, characterized in that: The delay unit is a circuit unit composed of a plurality of monostable multivibrators SN74LS221DR.

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