Drive acceleration circuit and circuitry

Abstract

The application provides a driving acceleration circuit, comprising: a driving power supply, comprising an output end and a reference signal end, the output end being used for outputting a driving signal, and the reference signal end being electrically connected to a connection end of a switching device and used for outputting a reference signal to the connection end; a first driving branch, the first driving branch being electrically connected to the output end of the driving power supply and a control end of the switching device and used for driving the switching device to turn on or turn off according to the driving signal; and a second driving branch, the second driving branch being parallel to the first driving branch, the second driving branch comprising an acceleration driving unit and a selection conduction unit, one end of the acceleration driving unit being electrically connected to the output end of the driving power supply, the other end of the acceleration driving unit being electrically connected to the control end of the switching device through the selection conduction unit, the selection conduction unit being turned on at different times to make the second driving branch conductive or open-circuit, and the acceleration driving unit being used for accelerating the switching device to turn on or turn off according to the driving signal when the second driving branch is conductive. The application also provides a circuit system.

Description

[0001] This application is a divisional application. The original application has the application number 202211054162.4 and the original application date is August 31, 2022. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of electronic circuit technology, and in particular to a driving acceleration circuit and circuit system. Background Technology

[0003] Semiconductor switching devices, such as insulated-gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), and novel wide-bandgap semiconductor devices (including wide-bandgap semiconductor materials SiC and GaNd), are widely used in electronic circuits. In some applications, to reduce the conduction losses of switching devices, slower switching speeds are considered, while simultaneously ensuring high-frequency on / off operation. This necessitates a drive acceleration circuit to guarantee the slow semiconductor switching device's high-frequency on / off capability. However, in some cases, the drive acceleration circuit causes the switching device to turn off extremely quickly, significantly increasing stress and posing a stress risk to the switching device. Summary of the Invention

[0004] This application provides a drive acceleration circuit for driving a switching device to turn on or off, the switching device having a control terminal and a connection terminal; the drive acceleration circuit includes: a drive power supply, including an output terminal and a reference signal terminal, the output terminal being used to output a drive signal, the reference signal terminal being electrically connected to the connection terminal of the switching device, and being used to output a reference signal to the connection terminal; a first drive branch, the first drive branch being electrically connected to the output terminal of the drive power supply and the control terminal of the switching device, and being used to drive the switching device to turn on or off according to the drive signal; and a second drive branch, connected in parallel with the first drive branch, the second drive branch including an acceleration drive unit and a selective conduction unit, one end of the acceleration drive unit being electrically connected to the output terminal of the drive power supply, the other end of the acceleration drive unit being electrically connected to the control terminal of the switching device through the selective conduction unit, the selective conduction unit being time-divisionally turned on to enable or disable the second drive branch, the acceleration drive unit being used to accelerate the switching device to turn on or off according to the drive signal when the second drive branch is turned on.

[0005] The aforementioned drive acceleration circuit includes a first drive branch and a second drive branch. The first drive branch is used to drive the switching device to turn on or off. The second drive branch includes an acceleration drive unit and a selection turn-on unit. The selection turn-on unit can control the second drive branch to be on or off, thereby enabling or disabling the acceleration drive unit in the second branch from the drive acceleration circuit. When the acceleration drive unit is on, it also drives the switching device to turn on or off. Based on the operating characteristics of the switching device, during certain specific operating periods, the acceleration drive unit can accelerate the switching device's on / off speed. However, during other specific operating periods, the acceleration drive unit may cause the current in the switching device to change too rapidly, increasing stress. Therefore, the aforementioned drive acceleration circuit, by setting a switch control circuit to control the operating state (on or off) of the second drive branch, can control the acceleration drive unit to be on during certain periods and off during other periods. Thus, the aforementioned drive acceleration circuit, while improving the on / off speed of the switching device, also avoids increasing the stress risk on the switching device.

[0006] In some embodiments, the selective conduction unit includes at least one semiconductor device, one end of which is connected to the acceleration drive unit and the other end of which is connected to the control terminal of the switching device. The at least one semiconductor device is turned on or off in a time-division manner to enable or disable the second drive branch.

[0007] In some embodiments, the at least one semiconductor device is a Zener diode, a transient suppression diode, or a switching device.

[0008] In this way, by setting semiconductor devices (ZDs, transient suppression diodes, or switching devices), the second drive branch can be easily controlled to be turned on or off.

[0009] In some embodiments, the selection and conduction unit includes two semiconductor devices, each of which is a Zener diode or a transient suppression diode; the anodes of the two semiconductor devices are electrically connected to each other, the cathode of one semiconductor device is electrically connected to the acceleration drive unit, and the cathode of the other semiconductor device is electrically connected to the control terminal of the switching device.

[0010] In this way, the connection directions of the two semiconductor devices are exactly opposite, and the two semiconductor devices are used to conduct or reverse cut off under the drive of drive signals in different directions. This allows the acceleration drive unit in the second drive branch to be put into the drive acceleration circuit during the switching process of the switching device. That is, it is beneficial to accelerate both the switching process of the switching device and the switching process of the switching device.

[0011] In some embodiments, the drive acceleration circuit includes at least two second drive branches connected in parallel, and the at least two second drive branches are time-divisionally turned on.

[0012] In this way, the turn-on and / or turn-off process of switching devices can be accelerated by multiple second drives in a time-sharing manner.

[0013] In some embodiments, the structures of each of the second drive branches are identical.

[0014] This facilitates the calculation and selection of parameters (such as resistance and capacitance values) of the corresponding components in each second drive branch.

[0015] In some embodiments, the resistance values ​​of each of the second drive branches are different.

[0016] Thus, by controlling the time-sharing conduction of each second drive branch, the turn-on and / or turn-off process of the switching device can be accelerated at different speeds at different times.

[0017] In some embodiments, the second drive branch is configured to be in an ON state when the switching device is in a turn-off delay period and in an OFF state when the switching device is in a turn-off action period; or, the second drive branch is configured to be in an ON state when the switching device is in both the turn-off delay period and the turn-off action period.

[0018] Thus, when the second drive branch is turned on during the turn-off delay period and open during the turn-off action period, it helps to accelerate the turn-off delay period of the switching device and avoids affecting the turn-off action period of the switching device. This helps to reduce the turn-off delay of the switching device and also helps to avoid increasing the stress on the switching device.

[0019] In some embodiments, the second driving branch is configured to be in a conducting state when the switching device is in the turn-on delay period and in an open state when the switching device is in the turn-on action period; or, the second driving branch is configured to be in a conducting state when the switching device is in both the turn-on delay period and the turn-on action period.

[0020] Thus, when the second drive branch is turned on during the turn-on delay period and turned off during the turn-on action period, it helps to accelerate the turn-on delay period of the switching device and avoids accelerating the turn-on action period of the switching device. This helps to accelerate the turn-on process of the switching device and also helps to avoid increasing the stress on the switching device.

[0021] In some embodiments, the acceleration drive unit includes one or any combination of a resistor, a capacitor, and a diode. The resistor, capacitor, and diode are connected in series or in parallel, with one end electrically connected to the output terminal of the drive power supply and the other end electrically connected to the selection and conduction unit.

[0022] In this way, charging and discharging paths can be provided during the turn-on and turn-off delay periods of the switching device.

[0023] In some embodiments, the first drive branch includes a first resistor, one end of which is connected to the output terminal of the drive power supply, and the other end is connected to the control terminal of the switching device. The acceleration drive unit includes a second resistor, one end of which is connected to the output terminal of the drive power supply, and the other end is connected to the selection and conduction unit.

[0024] In this way, the current in the first drive branch is kept less than the current when the second drive branch is turned on. When the second drive branch is turned on, the turn-on delay and / or turn-off delay are accelerated. When the first drive branch is turned on, the switching device maintains a normal current change rate during the turn-on and turn-off processes.

[0025] In some embodiments, the acceleration drive unit further includes a capacitor connected in series with a second resistor, one end of the second resistor being connected to the output terminal of the drive power supply and the other end being connected to the capacitor, the other end of the capacitor being connected to the selection conduction unit, and the capacitor being used to charge or discharge when the second drive branch is turned on.

[0026] Thus, the charging and discharging process of the capacitor helps to increase the current in the second drive branch, thereby accelerating the turn-on delay and / or turn-off delay of the switching device.

[0027] In some embodiments, the acceleration drive unit further includes a third resistor, which is connected in parallel with the capacitor, and one end of the third resistor is connected to the second resistor and the other end is connected to the selection conduction unit. The third resistor and the capacitor are time-divisionally connected to the second drive branch.

[0028] Thus, when the capacitor is connected to the second drive branch, the second drive branch has a larger current, which accelerates the turn-on and / or turn-off of the switching device. When the third resistor is connected to the second drive branch, the second drive branch has a smaller current, so that the normal turn-on and turn-off of the switching device is not affected, avoiding stress risks.

[0029] In some embodiments, the sum of the resistance values ​​of the second resistor and the third resistor is greater than the resistance value of the first resistor.

[0030] Thus, when the third resistor is connected to the second drive branch, the current in the second drive branch is less than the current in the first drive branch. The switching device is mainly charged and discharged through the first drive branch. The switching device can maintain a small current change rate during normal opening and closing operations, which helps to avoid stress risks.

[0031] A second aspect of this application provides a circuit system comprising: a switching device having a control terminal and a connection terminal; and a drive acceleration circuit, as described above, electrically connected to the control terminal and the connection terminal of the switching device, the drive acceleration circuit being used to drive the switching device to turn on or off.

[0032] The aforementioned circuit system includes a drive acceleration circuit, which comprises a first drive branch and a second drive branch. The first drive branch is used to drive the switching device to turn on or off. The second drive branch includes an acceleration drive unit and a selection turn-on unit. The selection turn-on unit controls the second drive branch to be on or off, thereby enabling or disabling the acceleration drive unit in the second branch from the drive acceleration circuit. When the acceleration drive unit is on, it also drives the switching device to turn on or off. Based on the operating characteristics of the switching device, during certain specific operating periods, the drive acceleration unit can accelerate the switching speed, while during other specific operating periods, it may cause the current to change too rapidly, increasing stress. Therefore, the aforementioned drive acceleration circuit, by setting a switch control circuit to control the operating state (on or off) of the second drive branch, can control the acceleration drive unit to be on during certain periods and off during others. Thus, the aforementioned circuit system and drive acceleration circuit, while improving the on and off speeds of the switching device, also avoids increasing the stress risk on the switching device. Attached Figure Description

[0033] Figure 1 A schematic diagram of the volt-ampere curve of the switching device when the driving power supply outputs a large pulse driving signal.

[0034] Figure 2 A schematic diagram of the volt-ampere curve of the switching device when the driving power supply outputs a small pulse driving signal.

[0035] Figure 3 This is a schematic diagram of the module structure of the circuit system according to Embodiment 1 of this application.

[0036] Figure 4 This is a schematic diagram of the circuit structure of the circuit system according to Embodiment 1 of this application.

[0037] Figure 5 for Figure 4A schematic diagram of the equivalent circuit structure of the circuit system during the turn-on delay period of the switching device.

[0038] Figure 6 for Figure 4 A schematic diagram of the equivalent circuit structure of the circuit system during the opening action of the switching device.

[0039] Figure 7 for Figure 4 A schematic diagram of the equivalent circuit structure of the circuit system during the turn-off delay period of the switching device.

[0040] Figure 8 for Figure 4 A schematic diagram of the equivalent circuit structure of the circuit system during the turn-off operation period of the switching device.

[0041] Figure 9 This is a schematic diagram of the circuit structure of the circuit system in a modified embodiment of Embodiment 1 of this application.

[0042] Figure 10 This is a schematic diagram of the circuit structure of the circuit system in another modified embodiment of Embodiment 1 of this application.

[0043] Figure 11 This is a schematic diagram of the circuit structure of the circuit system in another modified embodiment of Embodiment 1 of this application.

[0044] Figure 12 This is a schematic diagram of the circuit structure of the circuit system in another modified embodiment of Embodiment 1 of this application.

[0045] Figure 13 This is a schematic diagram of the circuit structure of the circuit system in another modified embodiment of Embodiment 1 of this application.

[0046] Figure 14 This is a schematic diagram of the circuit structure of the circuit system in Embodiment 2 of this application.

[0047] Figure 15 This is a schematic diagram of the circuit structure of the circuit system in a modified embodiment of Embodiment 2 of this application.

[0048] Figure 16 This is a schematic diagram of the circuit structure of the circuit system in another modified embodiment of Embodiment 2 of this application.

[0049] Figure 17 This is a schematic diagram of the circuit structure of the circuit system in Embodiment 3 of this application.

[0050] Figure 18 This is a schematic diagram of the circuit structure of the circuit system in a modified embodiment of Embodiment 3 of this application.

[0051] Figure 19This is a schematic diagram of the circuit structure of the circuit system in another modified embodiment of Embodiment 3 of this application.

[0052] Explanation of main component symbols Detailed Implementation

[0053] The embodiments of this application are described below with reference to the accompanying drawings.

[0054] It should be noted that when an element is considered to "connect" to another element, it can be directly connected to the other element or there may be an intervening element. When one or more elements or units are considered to "constitute" or "become" another element, it only indicates that the relationship exists in the described embodiment.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0056] This application provides a circuit system including a drive acceleration circuit and a switching device, applied to a drive circuit for semiconductor switching devices. The drive acceleration circuit is used to drive the switching device to turn on and off. The switching device in this application is a semiconductor switching device, such as an insulated-gate bipolar transistor, a metal-oxide-semiconductor field-effect transistor, or a novel wide-bandgap semiconductor device. The switching device has a control terminal, and the drive acceleration circuit drives the switching device to turn on and off by outputting a drive signal to the control terminal of the switching device.

[0057] In this application, the volt-ampere curve of the switching device from the start of switching to the end of switching can be found in [reference needed]. Figure 1 . Figure 1 The horizontal axis represents time, and the vertical axis represents the voltage V at the control terminal of the switching device. G T1 is defined as the turn-on delay period of the switching device, T2 is defined as the turn-on action period of the switching device, T4 is defined as the turn-off delay period of the switching device, and T5 is defined as the turn-off action period of the switching device. At the end of period T5, the switching device has been completely turned off, but in the period after period T5, V G It will continue to drop until it reaches the low level of the drive signal (-5V).

[0058] In this application, the threshold voltage of the switching device is +5V. That is, the gate voltage V at which the switching device reaches the Miller plateau. G It is +5V. That is, when VG When +5V is reached, the switching device is turned on; when V... G When the voltage is below +5V, the switching device is turned off. The drive signal periodically jumps between +15V and -5V, but due to the operating characteristics of semiconductor switching devices, the voltage of the switching device... G It's difficult to switch instantaneously; a voltage switch requires a certain time period to complete. For example, during the turn-on delay T1 of the switching device, V... G The voltage gradually increases from -5V to +5V; during the turn-off delay period T4 of the switching device, V G The voltage gradually decreases from +15V to +5V. The existence of the aforementioned turn-on delay period T1 and turn-off delay period T4 affects the turn-on and turn-off speeds of the switching device.

[0059] In this application, the basic drive unit 12 is used to drive the switching device to turn on or off, and the acceleration drive unit 13 is used to turn on the switching device during the turn-on delay period T1 and the turn-off delay period T4, thereby accelerating the turn-on delay period T1 and the turn-off delay period T4 and reducing the turn-on delay and turn-off delay.

[0060] When the pulse width is large, the current-voltage curve of the switching device is... Figure 1 As shown.

[0061] When the pulse width of the drive signal is small, please refer to [the relevant documentation]. Figure 2 In some cases, V G When the voltage reaches +5V, meaning the switching device is in the on-state period T2, the drive signal level jumps from +15V to -5V immediately upon activation, and the switching device will immediately begin to turn off. If the drive unit 13 accelerates the switching device at this time, it will directly accelerate the Miller plateau, speeding up the normal turn-off process of the switching device, causing a sharp increase in the rate of current change, and greatly increasing the stress on the switching device. Switching device 20 is at risk of stress.

[0062] Therefore, it can be seen that there is a certain time delay during the switching process (turn-on delay T1 and turn-off delay T4). Accelerating the turn-on delay T1 and turn-off delay T4 of the switching device helps reduce the switching delay and speeds up the turn-on and turn-off processes. However, when the pulse width of the drive signal is small, it can accelerate the Miller plateau of the switching device, that is, accelerate the normal turn-on action T2 and turn-off action T5, which may lead to an increased stress risk.

[0063] In this application, a drive signal with a pulse width greater than the sum of the turn-on delay period T1 and the turn-on action period T2 of the switching device is defined as a large pulse drive signal, and a drive signal with a pulse width less than or equal to the sum of the turn-on delay period T1 and the turn-on action period T2 of the switching device is defined as a small pulse drive signal.

[0064] Example 1 The drive acceleration circuit 10 of this embodiment accelerates the switching device during the turn-on delay period T1 and the turn-off delay period T4, and disconnects it during the turn-on action period T2 and the turn-off action period T5, thereby solving the above-mentioned technical problem of "increased stress on the switching device when the drive signal has a small pulse width".

[0065] Please see Figure 3 The circuit system 1 in this embodiment includes a drive acceleration circuit 10 and a switching device 20. In this embodiment, the switching device 20 has a control terminal G. The drive acceleration circuit 10 is electrically connected to the control terminal G of the switching device 20 to output a drive signal, thereby driving the switching device 20 to turn on or off. In this embodiment, the switching device 20 is an insulated-gate bipolar transistor (IGBT), and the control terminal G is the gate of the IGBT. The drive acceleration circuit 10 includes a drive power supply 11, a basic drive unit 12, an acceleration drive unit 13, and a selection conduction unit 14. In this embodiment, the basic drive unit 12 constitutes a first drive branch 15, and the acceleration drive unit 13 and the selection conduction unit 14 are connected in series to form a second drive branch 16. The first drive branch 15 and the second drive branch 16 are used to provide a charging and discharging path for the switching device 20 when it is on. The acceleration drive unit 13 and the selection conduction unit 14 are connected in series and then in parallel with the basic drive unit 12, that is, the first drive branch 15 and the second drive branch 16 are connected in parallel.

[0066] The driving power supply 11 has an output terminal out and a signal reference terminal GND. The output terminal out is used to output a driving signal, and the signal reference terminal GND is used to output a reference signal as a reference ground. The switching device 20 also includes a connection terminal E. In this embodiment, the connection terminal is the emitter. In other embodiments, the connection terminal E can also be the collector. The reference ground signal reference terminal GND is electrically connected to the connection terminal E. The driving signal output from the output terminal out is applied to the control terminal G of the switching device 20. In this embodiment, the selection and conduction unit 14 is used to control the working state of the second driving branch 16. That is, the second driving branch 16 is controlled by the selection and conduction unit 14 to be in a conducting state or an open state, thereby causing the acceleration driving unit 13 to be connected to the driving acceleration circuit 10 or disconnected from the driving acceleration circuit 10 (that is, to make the acceleration driving unit 13 connected to the driving acceleration circuit 10 or disconnected from the driving acceleration circuit 10).

[0067] In this embodiment, the driving signal is a pulse signal. When the driving signal is in the first state (e.g., a high level state, taking 15V as an example), the driving switch device 20 is turned on, and when the driving signal is in the second state (e.g., a low level state, taking -5V as an example), the driving switch device 20 is turned off.

[0068] In this embodiment, the operating state of the second drive branch 16 is controlled by the selection of the conduction unit 14 to enable the acceleration drive unit 13 to be engaged during the turn-on delay period T1 and the turn-off delay period T4 of the switching device 20, and the operating state of the second drive branch 16 is controlled by the selection of the conduction unit 14 to enable the acceleration drive unit 13 to be disengaged during the turn-on operation period T2 and the turn-off operation period T5 of the switching device 20. That is, the second drive branch 16 is controlled to be in a conducting state during the turn-on delay period T1 and the turn-off delay period T4 of the switching device 20, and the second drive branch 16 is controlled to be in an open state during the turn-on operation period T2 and the turn-off operation period T5 of the switching device 20.

[0069] The basic drive unit 12 and the acceleration drive unit 13 include one or any combination of resistors, capacitors, and diodes. The number of resistors, capacitors, and diodes can be one or more, and the resistors, capacitors, and diodes can be connected in series or in parallel.

[0070] Please see Figure 4 In this embodiment, the basic driving unit 12 includes a first resistor R1, the acceleration driving unit 13 includes a second resistor R2 and a capacitor C, and the selection and conduction unit 14 includes a first Zener diode V. Z1 Second Zener diode V Z2 The second resistor R2, capacitor C, and first Zener diode V Z1 and the second Zener diode V Z2 They are connected in series, with the second resistor R2 also electrically connected to the output terminal out of the drive power supply 11, and the second Zener diode V... Z2 The control terminal G of the switching device 20 is also electrically connected. In this embodiment, the first Zener diode V... Z1 The negative terminal is connected to the output terminal OUT of the drive power supply 11, and the positive terminal is connected to the switching device 20; the second Zener diode V Z2 The positive terminal is electrically connected to the output terminal out of the drive power supply 11, and the negative terminal is electrically connected to the switching device 20. The first resistor R1 is electrically connected between the output terminal out of the drive power supply 11 and the control terminal G of the switching device 20, and is also connected to the second resistor R2, the capacitor C, and the first Zener diode V. Z1 and the second Zener diode V Z2 in parallel.

[0071] In this embodiment, the threshold voltage of the switching device 20 is 5V and the first Zener diode V is... Z1Second Zener diode V Z2 Using a breakdown voltage of 10V as an example Figure 4 The working principle of circuit system 1 shown.

[0072] Please see Figure 5 During the turn-on delay period T1, the drive signal is at a high level (+15V). Under the drive signal, the control terminal G of the switching device 20 experiences a voltage V. G The voltage gradually increases from -5V to the threshold voltage +5V (i.e., the Miller plateau of the switching device 20 in this embodiment), at which point the first Zener diode V... Z1 Reverse breakdown, operating voltage 10V, second Zener diode V Z2 In forward conduction, it behaves as a diode. At this time, both the first driving branch 15 and the second driving branch 16 are in the conducting state. In the second driving branch 16, the second resistor R2 and the capacitor C can provide a sufficiently large gate driving peak current, so that the switching device 20 is charged through the first driving branch 15 and accelerated through the second driving branch 16, thereby accelerating the turn-on delay process of the switching device 20.

[0073] Please see Figure 6 During the start-up period T2, the voltage V at the control terminal G is... G The threshold voltage of the switching device has been reached +5V. At this time, the switching device 20 is turned on, selecting the first Zener diode V in the conduction unit 14. Z1 When the circuit is cut off, the second drive branch 16 is in an open circuit state. At this time, only the first drive branch 15 is turned on, and the switching device 20 is charged only through the first drive branch 15. The charging speed is reduced compared to the turn-on delay period, keeping the current change rate of the switching device 20 small, thereby avoiding stress risk.

[0074] In normal operation of switching device 20, the first drive branch 15 remains continuously on, while the second drive branch 16 remains continuously open. Although the voltage V at control terminal G... G The voltage has exceeded +5V, and switching device 20 is already conducting. However, to prevent fluctuations in the drive signal from causing switching device 20 to turn off erroneously, the high level of the drive signal needs to be greater than +5V, so that the voltage V at the control terminal G... G After reaching the Miller platform, it continued to rise to +15V.

[0075] Please see Figure 7 During the turn-off delay period T4, the drive signal is at a low level (-5V). Under the drive of the drive signal, the voltage at the control terminal G of the switching device 20 gradually decreases from +15V to the threshold voltage +5V, and the voltage at the first Zener diode V... Z1 Forward conduction is manifested as a diode, and the second Zener diode V Z2Reverse breakdown occurs when the operating voltage is 10V. At this time, the first drive branch 15 and the second drive branch 16 are simultaneously turned on. In the second drive branch 16, the second resistor R2 and the capacitor C can provide a low-impedance discharge path, accelerating the turn-off delay process of the switching device 20.

[0076] Please see Figure 8 During the turn-off period T5, the second Zener diode V Z2 When the circuit is cut off, the second drive branch 16 is in an open circuit state. At this time, only the first drive branch 15 is conducting, and the switching device 20 discharges only through the first drive branch 15. The discharge speed is reduced, keeping the current change rate of the switching device 20 small, thereby avoiding stress risk.

[0077] During the period following the turn-off period T5 of the switching device 20, although the voltage V at the control terminal G... G The voltage is already below +5V, and switching device 20 is off. However, to prevent fluctuations in the drive signal from causing switching device 20 to turn on erroneously, the low level of the drive signal needs to be below +5V, so that the voltage V at the control terminal G... G After reducing to below +5V, continue reducing to -5V.

[0078] It should be understood that, in other embodiments, the voltage V at the control terminal G during normal operation of the switching device 20 is... G It doesn't have to be +15V; the voltage V at the control terminal G after the switching device 20 is turned off is... G It does not have to be -5V. The voltage value mentioned above in this embodiment is only for illustrative purposes.

[0079] As can be seen from the aforementioned operation of circuit system 1, the acceleration drive unit 13 accelerates the turn-on delay and turn-off delay processes during the turn-on delay period T1 and the turn-off delay period T4, but does not accelerate the normal turn-on and turn-off processes of the switching device 20. When the switching device 20 reaches the Miller plateau, the corresponding Zener diode (V) in the conduction unit 14 is selected. Z1 or V Z2 The circuit is cut off, thereby controlling the second drive branch 16 where the acceleration drive unit 13 is located to be in an open circuit state, which does not accelerate the charging and discharging process of the switching device 20, so that the current change rate of the switching device 20 is stable, which can effectively suppress voltage spikes, reduce the stress risk of the switching device 20, and solve the technical problem that the aforementioned drive signal with a small pulse width is prone to increase the stress of the switching device 20.

[0080] To precisely control the second drive branch 16 to be in an open-circuit state during the turn-on period T2 and the turn-off period T5 of the switching device 20 (i.e., when at the Miller plateau), a Zener diode V matching the operating voltage needs to be selected based on the threshold voltage of the switching device 20 and the high and low levels of the drive signal. Z1 and VZ2 .

[0081] In this embodiment, the switching speed of the switching device 20 is related to the values ​​of capacitor C, first resistor R1, and second resistor R2. A specific switching speed can be obtained by selecting a capacitor C with a specific capacitance value and a first resistor R1 and a second resistor R2 with specific resistance values. A larger capacitance value and a smaller resistance value result in a larger charging and discharging current and a faster charging and discharging speed of the switching device 20; conversely, a smaller capacitance value and a larger resistance value result in a smaller charging and discharging current and a slower charging and discharging speed of the switching device 20.

[0082] In this embodiment, the resistance of the first resistor R1 is greater than that of the second resistor R2. This results in a smaller charging and discharging current and a smaller rate of change of current when the second driving branch 16 is open and the first driving branch 15 is charging and discharging. This is beneficial for the normal opening and closing of the switching device 20 and reduces the stress risk of the switching device 20.

[0083] In one modified embodiment, the aforementioned first Zener diode V Z1 and / or the second Zener diode V Z2 It can also be replaced with other semiconductor devices such as transient voltage suppressor (TVS) diodes and switching devices. In another modified embodiment, the circuit structures of the basic drive unit 12 and the acceleration drive unit 13 can also be different, as long as a charging and discharging path can be provided.

[0084] In this embodiment, the first Zener diode V is used. Z1 The operating characteristics of the first Zener diode V Z1 During the turn-on delay period T1, the switching device 20 breaks down in reverse, and during the turn-on operation period T2, it is turned off, thereby controlling whether the acceleration drive unit 13 is put into the drive acceleration circuit 10 or cut off from the drive acceleration circuit 10. Similarly, the second Zener diode V is used. Z2 The operating characteristics of the second Zener diode V Z2 During the turn-off delay period T4 of the switching device 20, reverse breakdown occurs, and during the turn-off action period T5, the device is cut off, thereby controlling the acceleration drive unit 13 to be either put into the drive acceleration circuit 10 or cut out of the drive acceleration circuit 10.

[0085] In other modified embodiments, the selection and conduction unit 14 includes a first Zener diode V. Z1 Or the second Zener diode V Z2 Instead of including the first Zener diode V Z1 Second Zener diode V Z2 That is, in other modified embodiments, the selection and conduction unit 14 may only include the first Zener diode V. Z1 With the second Zener diode VZ2 One of them. For example, see Figure 9 The selection and conduction unit 14 includes a first Zener diode V. Z1 At that time, the selection of the conduction unit 14 is used to control the operating state of the second drive branch 16 during the turn-on process of the switching device 20 (including the turn-on delay period T1 and the turn-on action period T2). For example, please refer to Figure 10 The selected conduction unit 14 includes a second Zener diode V. Z2 When the switching device 20 is turned off, the selection unit 14 is used to control the working state of the second drive branch 16 during the turn-off process (including the turn-off delay period T4 and the turn-off action period T5).

[0086] Figure 9 and Figure 10 In the modified embodiment shown, the selection of the conduction unit 14 includes only the first Zener diode V. Z1 With the second Zener diode V Z2 One of these advantages is its ability to adapt to the needs of switching devices 20 in different circuit systems.

[0087] Please see Figure 11 In other modified embodiments, the acceleration drive unit 13 does not include capacitor C. In this modified embodiment, the resistance value of the second resistor R2 is much smaller than the resistance value of the first resistor R1, so the charging and discharging current of the second drive branch 16 is much larger than the charging and discharging current of the first drive branch 15, and the switching device 20 can be quickly charged and discharged through the second drive branch 16 to achieve rapid opening or closing.

[0088] Please see Figure 12 and Figure 13 In a modified embodiment where the acceleration drive unit 13 does not include capacitor C, the switch drive unit 14 may be as follows: Figure 8 and Figure 10 The ground shown only includes the first Zener diode V. Z1 With the second Zener diode V Z2 One of them, I will not go into details.

[0089] In summary, the circuit system 1 described above in this embodiment includes a drive acceleration circuit 10, which includes a selection conduction unit 14. The selection conduction unit 14 controls the acceleration drive unit 13 to be in a conducting state during the turn-on delay period T1 and the turn-off delay period T4, thus accelerating the turn-on delay period T1 and the turn-off delay period T4. The selection conduction unit 14 also controls the acceleration drive unit 13 to be in an open-circuit state during the turn-on action period T2 and the turn-off action period T5, thus not accelerating the turn-on action period T2 and the turn-off action period T5. In this way, the drive acceleration circuit 1 selectively accelerates the charging and discharging process of the switching device 20. While ensuring the acceleration of the turn-on delay and the turn-off delay, it also avoids accelerating the normal turn-on and turn-off processes, thereby effectively suppressing voltage spikes, reducing the stress risk of the switching device 20, and solving the technical problem that the aforementioned drive signal with a small pulse width easily leads to an increase in stress on the switching device.

[0090] Example 2 Please see Figure 14 In this embodiment, circuit system 2 and Figure 4-10 The main difference in the illustrated embodiment is that the acceleration drive unit 13 of the second drive branch 16 further includes a third resistor R3, which is connected in series with the second resistor R2 and in parallel with the capacitor C. In this embodiment, the resistance of the third resistor R3 is much greater than the resistances of the first resistor R1 and the second resistor R2, and the resistance of the second resistor R2 is less than the resistance of the first resistor R1. In this embodiment, the capacitor C and the third resistor R3 are connected to the second drive branch 16 in a time-sharing manner.

[0091] In this embodiment, during the turn-on delay period T1, the switching device 20 is charged through the first drive branch 15 and the second drive branch 16. Specifically, the switching device 20 is charged through the second resistor R2 and capacitor C in the second drive branch 16, thereby enabling the acceleration drive unit 13 to accelerate the turn-on process of the switching device 20 during the turn-on delay period T1.

[0092] During the activation period T2, capacitor C in the acceleration drive unit 13 has been charged to a certain voltage. At this time, the path formed by the second resistor R2 and the third resistor R3 is conductive. The total resistance of the second drive branch 16 is the sum of the resistances of the second resistor R2 and the third resistor R3, which is much greater than the resistance of the first resistor R1 in the first drive branch 15. Although both the first drive branch 15 and the second drive branch 16 are conductive at this time, because the resistance on the second drive branch 16 is much greater than the resistance on the first drive branch 15, the charging current on the second drive branch 16 will be much smaller than the charging current on the first drive branch 15. That is, at this time, the switching device 20 is mainly charged through the first drive branch 15, and the current change rate is small, which will not affect the normal activation of the switching device 20.

[0093] During the turn-off delay period T4, the drive signal transitions to a low level, and the switching device 20 begins to discharge. At this time, both the first drive branch 15 and the second drive branch 16 are turned on. Specifically, the switching device 20 discharges through the second resistor R2 and capacitor C in the second drive branch 16, thereby accelerating the discharge process of the switching device 20 during the turn-off delay period T4 by the acceleration drive unit 13.

[0094] During the turn-off period T5, capacitor C in the acceleration drive unit 13 is in an open-circuit state. At this time, the path formed by the second resistor R2 and the third resistor R3 is conductive, and the switching device 20 also charges and discharges through the first drive branch 15 and the second drive branch 16. Specifically, the switching device 20 charges and discharges through the second resistor R2 and the third resistor R3 in the second drive branch 16. The total resistance of the second drive branch 16 is much greater than the total resistance of the first resistor R1, therefore the discharge current of the first drive branch 15 is much greater than the discharge current of the second drive branch 16. That is, the switching device 20 mainly discharges through the first drive branch 15, and the current change rate is small, which will not affect the normal turn-off of the switching device 20.

[0095] That is, in this embodiment, even if the selected conduction unit 14 fails to cut off the second drive branch 16, after the capacitor C is fully charged, the capacitor C can cut off the second drive branch 16. This allows the third resistor R3 to replace the capacitor C and be connected to the second drive branch 16, thus effectively reducing the turn-on and turn-off speed of the switching device 20.

[0096] Please see Figure 15 and Figure 16 In a modified embodiment of this example, the selection and conduction unit 14 may include only the first Zener diode V. Z1 With the second Zener diode V Z2 One of them, with Figure 9 and Figure 10 The embodiments shown are similar and will not be described again.

[0097] In summary, the circuit system 2 and the drive acceleration circuit 10 of this embodiment can achieve all the beneficial effects described in Embodiment 1. Furthermore, when the selection and conduction unit 14 fails to cut off the second drive branch 16, the charging and discharging state of the capacitor C can be used to control the second drive branch 16 to be engaged or disengaged.

[0098] Example 3 Please see Figure 17 The main difference between the circuit system 3 in this embodiment and those in embodiments one and two is that the driving acceleration circuit 10 includes at least two second driving branches 16, and each second driving branch 16 is connected in parallel. This embodiment uses two second driving branches 16 as an example for illustration.

[0099] In this embodiment, each of the second driving branches 16 operates in a time-sharing manner, and the charging and discharging currents of each second driving branch 16 are different when they are turned on. In this embodiment, by selecting second resistor R2 with different resistance values ​​and / or capacitor C with different capacitance values, each of the second driving branches 16 has different charging and discharging currents when it is turned on. In this embodiment, by selecting the first Zener diode V in the selection and conduction unit 14... Z1 The second Zener diode V Z2 They have different breakdown voltages so that each of the second drive branches 16 is turned on in a time-sharing manner. That is, the second drive branches 16 are not turned on at the same time.

[0100] Thus, during the turn-on delay period T1 and the turn-off delay period T4, the two second drive branches 16 are controlled to turn on in a time-division manner by the selection and conduction unit 14 in each second drive branch 16, so that the switching device 20 has different charging and discharging rates in each sub-period within the turn-on delay period T1 and the turn-off delay period T4. For example, the charging and discharging current of each second drive branch 16 when it is turned on can be set to control the charging and discharging rate of the switching device 20 to decrease in each sub-period within the turn-on delay period T1 and the turn-off delay period T4, and finally reach the charging and discharging rate at the Miller plateau.

[0101] In the driving acceleration circuit 10 of this embodiment, the structure of each second driving branch 16 can be any of the structures of the second driving branch 16 described in Embodiments 1 and 2, for example... Figure 18 and Figure 19 The structure shown in the example will not be described again.

[0102] The circuit system 3 and the drive acceleration circuit 10 of this embodiment can achieve all the beneficial effects described in Embodiments 1 and 2. Furthermore, the switching device 20 can be controlled to have a gradual charging and discharging speed during the turning-on and turning-off processes.

[0103] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A driving acceleration circuit for driving a switching device to turn on or off, the switching device having a control terminal and a connection terminal; characterized in that, The drive acceleration circuit includes: The driving power supply includes an output terminal and a reference signal terminal. The output terminal is used to output a driving signal, and the reference signal terminal is electrically connected to the connection terminal of the switching device and is used to output a reference signal to the connection terminal. A first driving branch, electrically connected to the output terminal of the driving power supply and the control terminal of the switching device, is used to drive the switching device to turn on or off according to the driving signal; and The second drive branch is connected in parallel with the first drive branch. The second drive branch includes an acceleration drive unit and a selection conduction unit. One end of the acceleration drive unit is electrically connected to the output terminal of the drive power supply, and the other end of the acceleration drive unit is electrically connected to the control terminal of the switching device through the selection conduction unit. When the pulse width of the drive signal is less than or equal to the sum of the turn-on delay period and the turn-on action period of the switching device, the selection conduction unit is used to turn on the switching device when it is in the turn-off delay period and turn off the switching device when it is in the turn-off action period. The acceleration drive unit is used to accelerate the turn-off of the switching device according to the drive signal when the second drive branch is on.

2. The driving acceleration circuit as described in claim 1, characterized in that, The selective conduction unit includes at least one semiconductor device, one end of which is connected to the acceleration drive unit and the other end of which is connected to the control terminal of the switching device. The at least one semiconductor device is turned on or off in a time-division manner so that the second drive branch is turned on or off.

3. The driving acceleration circuit as described in claim 2, characterized in that, The at least one semiconductor device is a Zener diode, a transient suppression diode, or a switching device.

4. The driving acceleration circuit as described in claim 2 or 3, characterized in that, The selected conduction unit includes two semiconductor devices, each of which is a Zener diode or a transient suppression diode. The anodes of the two semiconductor devices are electrically connected to each other, the cathode of one semiconductor device is electrically connected to the acceleration drive unit, and the cathode of the other semiconductor device is electrically connected to the control terminal of the switching device.

5. The driving acceleration circuit as described in any one of claims 1-4, characterized in that, The drive acceleration circuit includes at least two second drive branches connected in parallel, and the at least two second drive branches are turned on in a time-division manner.

6. The driving acceleration circuit as described in claim 5, characterized in that, Each of the second drive branches has the same structure.

7. The driving acceleration circuit as described in claim 5 or 6, characterized in that, The resistance values ​​of each of the second drive branches are different.

8. The driving acceleration circuit as described in any one of claims 1-7, characterized in that, When the pulse width of the driving signal is greater than the sum of the turn-on delay period and the turn-on action period of the switching device, the second driving branch is used to be in the on state when the switching device is in both the turn-off delay period and the turn-off action period.

9. The driving acceleration circuit as described in any one of claims 1-8, characterized in that, When the pulse width of the driving signal is greater than the sum of the turn-on delay period and the turn-on action period of the switching device, the second driving branch is used to be in the on state when the switching device is in both the turn-on delay period and the turn-on action period.

10. The driving acceleration circuit as described in any one of claims 1-9, characterized in that, The acceleration drive unit includes one or any combination of resistors, capacitors, and diodes. One end of the resistors, capacitors, and diodes or any combination thereof is connected in series or in parallel, and the other end is electrically connected to the output terminal of the drive power supply.

11. The driving acceleration circuit as described in claim 10, characterized in that, The first driving branch includes a first resistor, one end of which is connected to the output terminal of the driving power supply, and the other end is connected to the control terminal of the switching device. The acceleration drive unit includes a second resistor, one end of which is connected to the output terminal of the drive power supply, and the other end is connected to the selection and conduction unit.

12. The driving acceleration circuit as described in claim 11, characterized in that, The resistance of the first resistor is greater than the resistance of the second resistor.

13. The driving acceleration circuit as described in claim 12, characterized in that, The acceleration drive unit also includes a capacitor connected in series with a second resistor. One end of the second resistor is connected to the output terminal of the drive power supply, and the other end is connected to the capacitor. The other end of the capacitor is connected to the selection conduction unit. The capacitor is used to charge or discharge when the second drive branch is turned on.

14. The driving acceleration circuit as described in claim 13, characterized in that, The acceleration drive unit further includes a third resistor, which is connected in parallel with the capacitor. One end of the third resistor is connected to the second resistor, and the other end is connected to the selection and conduction unit. The third resistor and the capacitor are connected to the second drive branch in a time-sharing manner.

15. The driving acceleration circuit as described in claim 14, characterized in that, The sum of the resistance values ​​of the second resistor and the third resistor is greater than the resistance value of the first resistor.

16. A circuit system, characterized in that, include: A switching device having a control terminal and a connection terminal; as well as The drive acceleration circuit as described in any one of claims 1-15 is electrically connected to the control terminal and the connection terminal of the switching device, and is used to accelerate the switching device's opening or closing process.

Images