A passive high voltage isolation semiconductor switch driving device

Abstract

This invention discloses a passive high-voltage isolated semiconductor switch driving device, belonging to the field of pulse power technology. This invention utilizes a narrow pulse signal to control the semiconductor switch's conduction. When no pulse signal is input, the junction capacitance of the semiconductor switch can only discharge charge through its own extremely large leakage resistance, thereby extending the drive voltage hold time and achieving long-term conduction of the semiconductor switch device controlled by the narrow pulse signal. This effectively avoids core saturation and reduces core size. A negative pulse is used to reliably turn off the semiconductor switch device, enabling effective driving of various types of semiconductor switches. The device of this invention adopts a modular and miniaturized design, can be integrated onto a PCB board and encapsulated, effectively reducing device size and facilitating expanded applications.

Description

Technical Field

[0001] This invention belongs to the field of pulse power technology, and more specifically, relates to a passive high-voltage isolation semiconductor switch driving device. Background Technology

[0002] In recent years, pulsed power technology has been increasingly widely used in national defense research, high-tech research, and civilian industries. However, its development also faces many limitations, such as switching technology. In conventional pulsed power technology, dielectric-filled switches such as gas switches and liquid switches have obvious drawbacks, including short lifespan, high losses, poor stability, and low repetition frequency. Improvements in switching speed and power capacity of semiconductor switches have enabled their application in the field of pulsed power technology, leading to all-solid-state pulsed power technology and opening up new avenues for its development.

[0003] In pulsed power technology applications, semiconductor switches operate under high voltage and high current conditions. To meet these requirements, semiconductor switches are often used in series. Ensuring synchronous drive and conduction of the semiconductor switches under high-potential floating conditions, while simultaneously isolating the signal generation circuit from the pulse power circuit, presents a significant challenge for semiconductor switch applications in pulsed power technology. In pulsed power applications, switches often operate at high potentials. Currently, common MOSFET (or IGBT) switches are three-terminal structures, with the gate-source terminal for drive and the drain-source terminal for power current sharing a pin—a limitation determined by their physical structure. Therefore, when using these devices, the isolation between the drive signal and the power circuit must be considered. Existing semiconductor switch driving methods are divided into active and passive driving methods. Active driving methods utilize optical fibers to achieve strong and weak current isolation, but require an isolation power supply module to power the photoelectric signal conversion. However, existing isolation power supply modules have low isolation voltages, generally not exceeding 6kV, which limits their application in high-voltage (above 10kV) applications. Another method uses transformer power supply, which has a very complex system design, requiring the design of both a low-side full-bridge inverter circuit and high-side insulation and rectification. Existing passive driving methods often use magnetic isolation, but due to the limitation of the volt-second product of the magnetic core, the magnetic core will saturate when the input pulse width is too long. Therefore, it is difficult to balance the driving pulse width and the magnetic core size, which limits the driving time of the semiconductor switch and, consequently, the pulse width of the output voltage of the pulse power supply device. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a passive high-voltage isolated semiconductor switch driving device, which aims to solve the technical problem that the driving pulse width and magnetic core volume of the existing magnetic isolation passive driving method are difficult to balance, thus limiting the driving time of the semiconductor switch.

[0005] To achieve the above objectives, the present invention provides a passive high-voltage isolated semiconductor switch driving device, comprising: a drive signal magnetic isolation transformer, and a first drive circuit and a second drive circuit connected to the secondary side of the drive signal magnetic isolation transformer;

[0006] The drive signal magnetic isolation transformer is used to isolate the high-voltage environment of the semiconductor switch to be turned on and to input a narrow pulse signal.

[0007] The first driving circuit is used to turn on when a positive pulse signal is input to charge the gate capacitor of the driven semiconductor switch, and turn on the semiconductor switch after reaching the driving level.

[0008] The second driving circuit is used to turn on when a negative pulse signal is input, so that the charge stored in the junction capacitance of the semiconductor switch is released and the junction capacitance is reverse-charged to form a negative polarity driving voltage, thereby turning off the semiconductor switch.

[0009] The first and second driving circuits are disconnected when there is no pulse signal input. The charge stored in the gate-source junction capacitance of the driven semiconductor switch can only be discharged through its own leakage resistance to maintain the driving voltage holding time of the semiconductor switch junction capacitance.

[0010] Furthermore, the first drive circuit includes a drive signal magnetic isolation transformer with the same name terminal, a first diode, a semiconductor switch junction capacitor, a fourth diode, a second MOSFET switch, and a drive signal magnetic isolation transformer with the opposite name terminal.

[0011] Furthermore, the second drive circuit includes a drive signal magnetic isolation transformer with a different polarity terminal, a third diode, a second diode, a first MOSFET switch, and a drive signal magnetic isolation transformer with the same polarity terminal; the second drive circuit and the first drive circuit share the semiconductor switch junction capacitance.

[0012] Furthermore, the drive signal magnetic isolation transformer includes a high-voltage pulse transmission line, a magnetic core, and enameled wire; the high-voltage pulse transmission line passes through the magnetic core; and the enameled wire is wound on the surface of the magnetic core.

[0013] A high-voltage pulse transmission line is used to input pulse signals; a magnetic core is used to transmit the magnetic field to the secondary side, inducing a pulse voltage signal that meets the driving level requirements.

[0014] Furthermore, the drive signal magnetic isolation transformer is potted.

[0015] Furthermore, the drive device adopts a modular design.

[0016] Furthermore, the drive signal magnetic isolation transformer, the first drive circuit, and the second drive circuit are integrated on a PCB board and encapsulated, with reserved external input and output interfaces.

[0017] Furthermore, the input signal of the drive signal magnetic isolation transformer is generated by a microcontroller.

[0018] Overall, the above-described technical solutions conceived by this invention can achieve the following beneficial effects compared with the prior art.

[0019] This invention utilizes a low-voltage (≤±30V) narrow (within 100 microseconds) pulse signal to control the conduction of a semiconductor switch. When no pulse signal is input, the junction capacitance of the semiconductor switch can only discharge charge through its own extremely large leakage resistance, thereby extending the drive voltage hold time. This enables long-term conduction of the semiconductor switch device under narrow pulse signal control, effectively avoiding core saturation and reducing core size. The invention also utilizes negative pulses to achieve reliable turn-off of the semiconductor switch device, effectively driving various types of semiconductor switches.

[0020] This invention employs a modular and miniaturized design, which can effectively reduce the size of the device and facilitate expanded applications. Attached Figure Description

[0021] Figure 1 This is a topology diagram of a passive high-voltage isolation semiconductor switch driving device provided in an embodiment of the present invention.

[0022] Figure 2 The present invention provides a system circuit diagram of a passive high-voltage isolation semiconductor switch driving device under the action of a positive pulse signal.

[0023] Figure 3 The present invention provides a system circuit diagram of a passive high-voltage isolation semiconductor switch driving device under the action of a negative pulse signal.

[0024] Figure 4 The following is a timing diagram of the input signal and output pulse of a passive high-voltage isolation semiconductor switch driving device provided in an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of a PCB board for a passive high-voltage isolation semiconductor switch driving device provided in an embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of a plastic packaged passive high-voltage isolation semiconductor switch driver device provided in an embodiment of the present invention.

[0027] Figure 7 The actual driving timing diagram of a passive high-voltage isolation semiconductor switch driving device provided in an embodiment of the present invention is shown.

[0028] Figure 8The semiconductor switch turn-on timing diagram is provided for a passive high-voltage isolation semiconductor switch driving device according to an embodiment of the present invention.

[0029] Figure 9 This is a schematic diagram of the driving signal driving time of a passive high-voltage isolation semiconductor switch driving device provided in an embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0031] This invention utilizes a magnetic core in conjunction with a high-voltage line to achieve high-low voltage isolation; it uses the junction capacitance of a semiconductor switch to maintain the driving time, enabling long pulse width driving; it uses primary-side positive and negative narrow pulses to control the driving pulse width, allowing the use of a small-sized magnetic core and miniaturizing the driving module; the driving module has the ability to output negative pulses, ensuring reliable switching of the semiconductor switch; the system adopts an integrated design, realizing modularization of the driving device, which can be used directly without considering isolation, power supply, and other issues.

[0032] This invention discloses a passive high-voltage isolation semiconductor switch driving device, such as... Figure 1 As shown, it mainly includes a drive signal magnetic isolation transformer, a signal processing module, and a pulse output module.

[0033] The signal processing module shapes and controls the pulse signal, controlling the on / off state of the two drive circuits. Specifically, the signal processing module mainly includes diodes and MOSFET switches. When a pulse signal is input to the magnetic isolation transformer, the boosted pulse signal turns on the MOSFET switch. The pulse signal, through the diode and MOSFET switch, forms a circuit to charge the gate capacitor of the semiconductor switch. Once the drive level is reached, the semiconductor switch is turned on. Figure 2 As shown in the diagram, the solid line represents the conduction loop. When a positive pulse signal is input, the pulse signal is boosted by transformer T. The high level causes diode D1 to conduct, and the high level is transmitted to the gate of MOSFET switch S2, causing the MOSFET switch to conduct. The pulse voltage passes through diode D1 and the semiconductor switch junction capacitance C. gs The circuit formed by diode D4 and MOSFET switch S2 is a semiconductor switching junction capacitor C. gs The capacitor charges until its voltage reaches the driving voltage, thus turning on the semiconductor switch. For example... Figure 3As shown in the diagram, the solid line represents the conduction loop. When a negative pulse signal is input, the pulse signal is boosted by transformer T. The high level causes diode D3 to conduct, and the high level is transmitted to the gate of MOSFET switch S1, causing the MOSFET switch to conduct. The pulse voltage passes through diode D3 and the semiconductor switch junction capacitance C. gs The circuit formed by diode D2 and MOSFET switch S1 is a semiconductor switching junction with capacitance C. gs Reverse charging allows for rapid release of charge on the capacitor, simultaneously achieving a negative drive voltage and enabling reliable turn-off of the semiconductor switch. When there is no pulse input, MOSFET switches S1 and S2 are off, and the charge on the semiconductor switch junction capacitor can only be released through leakage resistance, resulting in a slow voltage drop and prolonged drive time. Figure 4 As shown, by inputting a low-voltage, narrow pulse to the FPGA, the output pulse signal can be made into a long pulse signal that meets the driving requirements of the semiconductor switch. The conduction time of the semiconductor switch can be controlled by adjusting the time interval between the positive and negative pulse signals.

[0034] Preferably, the diodes D1-D4 are surface-mount diodes with a withstand voltage of 30V, a current of 100mA, and a 0805 package. The MOSFET switch is a dual-channel integrated N-MOSFET manufactured by Infineon Technologies, with a withstand voltage of 30V, a current of 16A, and an SO-8 package. The integrated MOSFET further reduces the size of the device.

[0035] A drive signal magnetic isolation transformer is used for high-voltage isolation, signal and power transmission in power circuits, converting low-potential side signals into high-potential side signals to achieve high-low potential isolation. Preferably, such as... Figure 5 As shown in Figure 501, the drive signal magnetic isolation transformer comprises a high-voltage pulse transmission line, a magnetic core, and enameled wire, forming an isolation transformer. The high-voltage pulse transmission line passes through the magnetic core, and the enameled wire is wound several turns on the magnetic core. The pulse signal generated by the signal generation circuit is input through the high-voltage pulse transmission line. The pulse transmission line further enhances the insulation capability, thereby reducing the size of the magnetic core and the structure of the device. If it is necessary to further increase the isolation voltage, potting measures can be taken for the drive signal isolation transformer. The isolation voltage level of the drive signal magnetic isolation transformer is determined by the high-voltage pulse transmission line and the potting material, and can be flexibly adjusted for different voltage levels.

[0036] The input signal of the drive signal magnetic isolation transformer can be generated by any signal generating device. Preferably, in this embodiment of the invention, a microcontroller is used to generate the input signal for timing control.

[0037] The pulse output module connects to the gate and source of the semiconductor switch to drive the semiconductor switch.

[0038] Specifically, the pulse output module is directly connected to the gate and source of the semiconductor switch, and uses the signal processing circuit to output pulses to drive the semiconductor switch. The drive signal magnetic isolation transformer, signal processing module, and pulse output module are all integrated on the PCB board and encapsulated, with only external input and output interfaces reserved, realizing the modularity and miniaturization of the device, and eliminating the need for external design during use.

[0039] like Figure 5 As shown, the drive signal magnetic isolation transformer 501 and the pulse output module 503 are placed on the front of the PCB board 502, while the signal processing module 504 uses surface-mount components and is placed on the back of the PCB board. This layered design further reduces the size of the device. Figure 6 As shown, the PCB board is plastic-encapsulated, with only the input interface 601 and output interface 603 reserved for external use. All other components are encapsulated inside the insulating material 602. The dimensions of the device after encapsulation are 45mm in length l, 20mm in width w, and 9mm in thickness h, which realizes the modularization and miniaturization of the equipment and improves the reliability of the equipment.

[0040] In one specific embodiment, the FPGA output signal is converted into positive and negative pulses with an amplitude of 10V by a driving circuit. The signal input of the isolation transformer uses 20kV silicone high-voltage wire, and the signal output uses 1-turn enameled wire. The isolation transformer turns ratio is 1:1. Under the driving of the positive and negative pulses, the voltage U between the gate and source of the silicon carbide MOSFET... gs Changes such as Figure 7 As shown in the figure, channel 1 is U gs Channel 2 is for input positive and negative polarity pulses. Under the action of the positive polarity pulse, the junction capacitance of the MOSFET is charged, the voltage reaches 10V and is maintained, realizing long pulse width drive of the semiconductor switch with narrow pulse width input, and realizing reliable turn-off under the action of the negative polarity pulse.

[0041] In this embodiment, under the action of a positive polarity pulse, the turn-on rise time of the silicon carbide MOSFET is as follows: Figure 8 As shown, the MOSFET charges to reach the positive polarity pulse amplitude within 120ns, and the conduction level of the silicon carbide MOSFET is 5V. Therefore, the conduction time of the MOSFET, that is, the time for the junction capacitance voltage to rise from 0 to 5V, is about 10ns. This scheme can realize the rapid turn-on of the semiconductor switch.

[0042] In this embodiment, under the action of a positive pulse, after the junction capacitance of the silicon carbide MOSFET is fully charged, a junction capacitance voltage higher than 5V is sufficient to ensure reliable conduction of the MOSFET. The voltage holding time is as follows: Figure 9As shown, under a positive pulse, the reliable on-time of the MOSFET is greater than 80ms, enabling long-pulse conduction of the semiconductor switch under a short pulse. To extend the on-time, a short positive pulse needs to be input to the drive module again within 80ms before the junction capacitance voltage drops to 5V. This method allows for continuous switch conduction under short pulses and effectively avoids core saturation, achieving passive high-voltage isolated semiconductor switch drive.

[0043] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A passive high-voltage isolation semiconductor switch driving device, characterized in that, include: A drive signal magnetic isolation transformer, and a first drive circuit and a second drive circuit connected to the secondary side of the drive signal magnetic isolation transformer; The drive signal magnetic isolation transformer is used to input low-voltage narrow pulse signals; The first driving circuit is used to turn on when a positive pulse signal is input to charge the gate capacitor of the driven semiconductor switch, and turn on the semiconductor switch after reaching the driving level. The second driving circuit is used to turn on when a negative pulse signal is input, so that the charge stored in the junction capacitance of the semiconductor switch is released quickly and the junction capacitance is reverse-charged to form a negative polarity driving voltage, thereby realizing the reliable turn-off of the semiconductor switch. The first and second driving circuits are disconnected when there is no pulse signal input. The charge stored in the gate-source junction capacitance of the driven semiconductor switch can only be discharged through its own leakage resistance to maintain the driving voltage holding time of the semiconductor switch junction capacitance. The first driving circuit includes a driving signal magnetic isolation transformer with the same name terminal, a first diode, a semiconductor switching junction capacitor, a fourth diode, a second MOSFET switch, and a driving signal magnetic isolation transformer with the opposite name terminal; the second driving circuit includes a driving signal magnetic isolation transformer with the opposite name terminal, a third diode, a semiconductor switching junction capacitor, a second diode, a first MOSFET switch, and a driving signal magnetic isolation transformer with the same name terminal. The anode of the first diode is connected to the same-name terminal of the drive signal magnetic isolation transformer. The cathode of the first diode is connected to the anode of the second diode, the anode of the semiconductor switching junction capacitor, and the gate of the second MOSFET switch. The drain of the second MOSFET switch is connected to the cathode of the fourth diode. The anode of the fourth diode is connected to the cathode of the semiconductor switching junction capacitor. The source of the second MOSFET switch is connected to the opposite-name terminal of the drive signal magnetic isolation transformer. The anode of the third diode is connected to the opposite terminal of the drive signal magnetic isolation transformer. The cathode of the third diode is connected to the anode of the fourth diode, the cathode of the semiconductor switching junction capacitor, and the gate of the first MOSFET switch. The drain of the first MOSFET switch is connected to the cathode of the second diode. The anode of the second diode is connected to the anode of the semiconductor switching junction capacitor. The source of the first MOSFET switch is connected to the same terminal of the drive signal magnetic isolation transformer. The drive signal magnetic isolation transformer includes a high-voltage pulse transmission line, a magnetic core, and enameled wire; the high-voltage pulse transmission line passes through the magnetic core; the enameled wire is wound on the surface of the magnetic core; A high-voltage pulse transmission line is used to input pulse signals; a magnetic core is used to transmit the magnetic field to the secondary side, inducing a pulse voltage signal that meets the driving level requirements.

2. The passive high-voltage isolation semiconductor switch driving device according to claim 1, characterized in that, The drive signal magnetic isolation transformer is potted.

3. A passive high-voltage isolation semiconductor switch driving device according to claim 1 or 2, characterized in that, The drive unit adopts a modular design.

4. The passive high-voltage isolation semiconductor switch driving device according to claim 3, characterized in that, The drive signal magnetic isolation transformer, the first drive circuit, and the second drive circuit are integrated on a PCB board and encapsulated, with reserved external input and output interfaces.

5. A passive high-voltage isolation semiconductor switch driving device according to any one of claims 4, characterized in that, The input signal of the drive signal magnetic isolation transformer is generated by a microcontroller.

Images