Switching tube control method, driving device and electronic equipment

Abstract

The invention relates to a control method of a switching tube, a driving device and electronic equipment, and belongs to the field of electronic circuits. The control method of the switch tube comprises the following steps: providing a multi-stage control strategy, and controlling the switch tube by using the control strategy so as to reduce the loss of the switch tube; wherein at least one of the multiple stages adopts a control strategy different from a square wave. According to the invention, the switch tube is controlled by dividing conventional square wave control into a multi-stage control strategy, and at least one of the stages adopts a control strategy different from the square wave control strategy to reduce the loss of the switch tube, thereby achieving the effects of reducing the heat productivity, prolonging the service life of the switch tube and saving energy.

Description

Technical Field

[0001] This application belongs to the field of electronic circuits, and particularly relates to a control method for a switching tube, a driving device, and an electronic device. Background Art

[0002] In a power electronics system, the losses of a switching tube mainly include conduction loss and switching loss. Among them, the conduction loss refers to the energy loss caused by the on-resistance of the device itself when the switching tube is in the on state. The switching loss refers to the energy loss generated during the transient process of the switching tube turning on and off, and this loss is particularly significant in high-frequency switching applications, directly affecting the efficiency and heat generation of the system. Therefore, optimizing the losses of the switching tube can not only save energy but also reduce the heat generation and improve the service life of the switching tube. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a control method for a switching tube, a driving device, and an electronic device to reduce the losses of the switching tube.

[0004] The embodiments of this application are implemented as follows: In a first aspect, an embodiment of this application provides a control method for a switching tube, including: providing a multi-stage control strategy and using the control strategy to control the switching tube to reduce the losses of the switching tube; wherein, at least one stage in the multi-stage adopts a control strategy different from a square wave.

[0005] In the above embodiment, by dividing the conventional square wave control into a multi-stage control strategy to control the switching tube, and at least one stage in the multi-stage adopts a control strategy different from a square wave to reduce the losses of the switching tube, thereby achieving the effects of reducing heat generation, improving the service life of the switching tube, and saving energy.

[0006] Combined with a possible implementation manner of the first aspect embodiment, the multi-stage includes a turn-on stage, an amplification stage, a saturation stage, and a turn-off stage; using the control strategy to control the switching tube includes: using at least one of the following control strategies to control the switching tube: Strategy 1: In the turn-on stage, drive the switching tube with a drive current greater than the starting current of the amplification stage to accelerate the turn-on of the switching tube; Strategy 2: In the amplification stage, drive the switching tube with a drive current positively correlated with the product of the input current of the switching tube and the target amplification factor to reduce the drive loss of the switching tube; Strategy 3: In the saturation stage, increase the amplification factor of the switching tube, or stop power supply to the drive end of the switching tube; Strategy 4: In the turn-off stage, turn off the switching tube with a negative voltage to accelerate the turn-off speed of the switching tube.

[0007] In the above embodiments, at least one of the above control strategies different from the square wave can be adopted to control the switching tube to reduce the switching loss. If control strategies different from the traditional square wave are adopted in all four stages, the loss of the switching tube can be minimized. For example, in the turn-on stage, a larger drive current is adopted to accelerate the turn-on of the switching tube and reduce the turn-on loss; in the amplification stage, a smaller amplification ratio is adopted to reduce the drive loss of the switching tube; in the saturation stage, by increasing the amplification ratio of the switching tube or stopping power supply to the drive end of the switching tube, the saturation voltage drop between the input end and the output end of the switching tube is reduced, thereby reducing the conduction loss of the switching tube; in the turn-off stage, the switching tube is turned off with a negative voltage to accelerate the turn-off speed of the switching tube, thereby reducing the switching loss of the switching tube.

[0008] Combined with a possible implementation manner of the first aspect embodiment, turning off the switching tube with a negative voltage includes: first stopping power supply to the drive end of the switching tube, and then pulling down the voltage of the drive end of the switching tube to be less than the voltage of the output end of the switching tube; or, first raising the voltage of the output end of the switching tube, and then discharging the voltage of the drive end of the switching tube.

[0009] In the above embodiments, by adopting the above method, the turn-off speed of the switching tube can be accelerated, thereby reducing the switching loss of the switching tube.

[0010] Combined with a possible implementation manner of the first aspect embodiment, the switching tube is a composite tube, and the composite tube includes a Darlington tube or an IGBT tube. Turning off the switching tube with a negative voltage includes: first discharging the voltage of the drive end of the low-power tube in the composite tube, and then discharging the voltage of the drive end of the high-power tube in the composite tube; or, first discharging the voltage of the drive end of the low-power tube in the composite tube, then raising the voltage of the output end of the high-power tube in the composite tube, and then discharging the voltage of the drive end of the high-power tube.

[0011] In the above embodiments, for a Darlington tube or an IGBT tube, by adopting the above method, the turn-off speed of the switching tube can be accelerated, thereby reducing the switching loss of the switching tube.

[0012] Combined with a possible implementation manner of the first aspect embodiment, in the amplification stage, the target amplification ratio is related to the parameters of the switching tube; and / or; in the saturation stage, the amplification ratio of the switching tube or the time of stopping power supply to the drive end of the switching tube is related to the parameters of the switching tube; wherein, the parameters include at least one of the temperature of the circuit where the switching tube is located, the peak current of the input end of the switching tube, and the input voltage of the switching tube.

[0013] In the above embodiment, the amplification factors in the amplification stage and the saturation stage are related to the parameters of the switch tube. Different parameters of the switch tube correspond to different amplification factors, and the time when the driving end stops supplying power is also related to the parameters of the switch tube. By taking into account the parameters of the switch tube, such as the temperature of the circuit in which the switch tube is located, the peak current at the input end of the switch tube, the input voltage of the switch tube and other parameters, the amplification factor or the time when the driving end stops supplying power is selected, which is beneficial to further reduce the loss of the switch tube.

[0014] In combination with a possible implementation method of the embodiment of the first aspect, the amplification factor of the switching tube is improved in the saturation stage, including: using any of the following methods to improve the amplification factor of the switching tube: Method 1: increasing the input current and the driving current of the switching tube at the same time, and the increase in the driving current is less than the increase in the input current; Method 2: increasing the input current of the switching tube, and the driving current of the switching tube remains unchanged; Method 3: increasing the input current of the switching tube and reducing the driving current of the switching tube.

[0015] In the above embodiments, any of the above methods can improve the amplification factor of the switch tube. By improving the amplification factor of the switch tube in the saturation stage, the saturation voltage drop between the input and output ends of the switch tube can be reduced, thereby reducing the conduction loss of the switch tube.

[0016] In combination with a possible implementation manner of the embodiment of the first aspect, the output end of the switching tube is grounded via a first switch, and the output end of the switching tube is also grounded via a capacitor, and a first diode and / or a second switch is also arranged between the output end of the switching tube and the capacitor; the method also includes: in the saturation stage, controlling the duration of the first switch being turned off according to the power supply demand of the capacitor, wherein the switching tube charges the capacitor when the first switch is turned off.

[0017] In the above embodiment, in the saturation stage, the duration of the first switch being turned off is controlled according to the power supply demand of the capacitor, thereby solving the problem of insufficient power supply and / or excessive power supply of VCC.

[0018] In combination with a possible implementation manner of the embodiment of the first aspect, the output end of the switching tube is also connected to the capacitor through a first diode, and the method further includes: in the shutdown stage, controlling the first switch to be turned off and the second switch to be turned on, so that the capacitor provides a reverse current from the driving end to the output end of the switching tube.

[0019] In the above embodiment, in the closing stage, the first switch is controlled to be turned off and the second switch is controlled to be turned on, so that the capacitor provides the switch tube with a reverse current from the driving end to the output end, speeds up the extraction of charge from the driving end, and improves the closing speed.

[0020] In a possible implementation manner combining with the embodiments of the first aspect, the driving end of the switching tube is connected to the current mirror through a second diode or MOS tube, and the method further includes: in the saturation stage, when the voltage of the driving end of the switching tube is greater than a preset voltage, gradually increase the current of the current mirror to reduce the conduction voltage difference of the current mirror.

[0021] In the above embodiment, in the saturation stage, when the voltage of the driving end of the switching tube is greater than a preset voltage, gradually increase the current of the current mirror to reduce the conduction voltage difference of the current mirror, thereby improving the driving ability of the switching tube.

[0022] In a second aspect, an embodiment of the present application further provides a switching tube driving device, including: a switching tube and a control circuit; the control circuit is connected to the driving end of the switching tube, and the control circuit is configured to provide a control strategy including multiple stages and use the control strategy to control the switching tube to reduce the loss of the switching tube; wherein, at least one stage of the multiple stages adopts a control strategy different from a square wave.

[0023] In a possible implementation manner combining with the embodiments of the second aspect, the control circuit includes: a capacitor, a first switch, and a first diode and / or a second switch. The output end of the switching tube is grounded through the first switch, and the output end of the switching tube is also grounded through the capacitor. A first diode and / or a second switch is further provided between the output end of the switching tube and the capacitor; the multiple stages include an opening stage, an amplification stage, a saturation stage, and a closing stage; in the opening stage and the amplification stage, the first switch is turned on, in the closing stage, the first switch is turned off, and in the saturation stage, the conduction or turn-off of the first switch is controlled according to the power supply requirement of the capacitor; when the first switch is turned off, the switching tube is used to charge the capacitor.

[0024] In a possible implementation manner combining with the embodiments of the second aspect, the output end of the switching tube is connected to the capacitor through the second switch; in the closing stage, the first switch is in an off state and the second switch is in an on state, and the capacitor provides a reverse current from the driving end to the output end of the switching tube.

[0025] In a possible implementation manner combining with the embodiments of the second aspect, the control circuit further includes: a third switch, and the driving end of the switching tube is also grounded through the third switch; in the closing stage, the third switch is in an on state.

[0026] In a possible implementation manner combining with the embodiments of the second aspect, the control circuit includes: a controller and a current mirror, and the driving end of the switching tube is connected to the current mirror through a second diode or a MOS tube; in the saturation stage, when the voltage at the driving end of the switching tube is greater than a preset voltage, the controller is configured to gradually increase the current of the current mirror to reduce the conduction voltage difference of the current mirror.

[0027] In a third aspect, an embodiment of the present application further provides an electronic device, including: a switching tube driving device provided as described in the embodiments of the second aspect and / or any possible implementation manner combining with the embodiments of the second aspect.

[0028] Other features and advantages of the present application will be described in the subsequent specification. The objectives and other advantages of the present application can be achieved and obtained through the structures specifically pointed out in the written specification and the drawings. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings. As shown in the drawings, the above-mentioned and other objectives, features, and advantages of the present application will become clearer.

[0030] Figure 1 It is a traditional driving waveform for driving a switching tube in the prior art.

[0031] Figure 2 It shows a schematic flowchart of a control method for a switching tube provided by an embodiment of the present application.

[0032] Figure 3 It shows a schematic structural diagram of a Darlington tube provided by an embodiment of the present application.

[0033] Figure 4 It shows schematic diagrams of various current waveforms for driving a single switching tube provided by an embodiment of the present application.

[0034] Figure 5 It shows a schematic diagram of a current waveform for driving a composite tube provided by an embodiment of the present application.

[0035] Figure 6 It shows a schematic circuit diagram of the first type for optimizing the turn-off duration of a single switching tube provided by an embodiment of the present application.

[0036] Figure 7 It shows a schematic circuit diagram of the first type for optimizing the turn-off duration of a composite tube provided by an embodiment of the present application.

[0037] Figure 8aThe figure shows a schematic circuit diagram of the second method provided by the embodiments of the present application for optimizing the turn-off duration of a single switching transistor.

[0038] Figure 8b The figure shows a schematic circuit diagram of the third method provided by the embodiments of the present application for optimizing the turn-off duration of a single switching transistor.

[0039] Figure 8c The figure shows a schematic circuit diagram of the fourth method provided by the embodiments of the present application for optimizing the turn-off duration of a single switching transistor.

[0040] Figure 9 The figure shows a schematic diagram of the connection between a control circuit and a switching transistor provided by the embodiments of the present application. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following embodiments can be used as examples to more clearly illustrate the technical solutions of the present application, but cannot be used to limit the protection scope of the present application. Those skilled in the art can understand that, without conflict, the features in the following embodiments and the embodiments can be combined with each other.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, relational terms such as "first", "second", etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0043] Furthermore, the term "and / or" in the present application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0044] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "connection" can be a direct connection or an indirect connection through an intermediate medium.

[0045] To reduce the loss of the switching device, an embodiment of the present application provides an efficient control method and driving device for the switching device. By using the control method shown in the present application, the loss of the switching device can be effectively reduced, and the usage efficiency of the switching device can be improved. The traditional driving method is Figure 1 the square wave driving shown, and the same high-level driving is used in the turn-on stage, amplification stage, and saturation stage of the switching device, while low-level driving is used in the turn-off stage of the switching device, resulting in large conduction loss and switching loss of the switching device. In the embodiment of the present application, the conventional square wave control is divided into a multi-stage control strategy to control the switching device, and at least one stage in the multi-stage adopts a control strategy different from the traditional square wave, so as to reduce the loss of the switching device.

[0046] The switching device shown in the present application can be a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), IGBT (Insulated Gate Bipolar Transistor), BJT (Bipolar Junction Transistor), Darlington transistor, etc.

[0047] The following combines Figure 2 , to illustrate the control method shown in the present application, including step S1 and step S2.

[0048] Step S1: Provide a multi-stage control strategy.

[0049] By dividing the conventional square wave control into a multi-stage control strategy, the above multi-stage includes a turn-on stage, an amplification stage, a saturation stage, and a turn-off stage, corresponding to 4 stages of the switching device. At least one stage in the multi-stage (such as 4 stages) adopts a control strategy different from the square wave.

[0050] In some possible implementation manners, the control strategies corresponding to at least 2 of the above 4 stages may be different, and the control strategies corresponding to the remaining stages may be the same. In some other possible implementation manners, the control strategy corresponding to each stage may be different. Of course, it is also possible that some stages adopt the control strategy shown in the present application, and some stages adopt the traditional control strategy, so that the control strategies corresponding to at least 2 stages are different. For example, at least one stage in the turn-on stage, amplification stage, saturation stage, and turn-off stage may adopt the control strategy shown in the present application, while the remaining stages adopt the traditional control strategy.

[0051] Since at least one stage adopts a control strategy different from the traditional square wave, the loss of the switching device can be reduced. If all four stages adopt a control strategy different from the traditional square wave, the loss of the switching device can be minimized.

[0052] Step S2: Control the switching device using a multi-stage control strategy to reduce the loss of the switching device.

[0053] The switching device can be controlled using at least one of the following control strategies: Strategy 1: In the turn-on stage, accelerate the turn-on of the switching device with a large drive current to reduce the turn-on loss. For example, drive the switching device with a drive current greater than the starting current of the amplification stage to accelerate the turn-on of the switching device.

[0054] Strategy 2: In the amplification stage, adopt a small amplification factor to reduce the drive loss of the switching device, and the drive current of the switching device changes with the input current of the switching device. For example, drive the switching device with a drive current positively correlated with the product of the input current of the switching device and the target amplification factor to reduce the drive loss of the switching device.

[0055] Strategy 3: In the saturation stage, increase the amplification factor of the switching device or stop power supply to the drive end of the switching device to reduce the saturation voltage drop between the input and output ends of the switching device, thereby reducing the conduction loss of the switching device.

[0056] Strategy 4: In the turn-off stage, turn off the switching device with a negative voltage to accelerate the turn-off speed of the switching device, thereby reducing the switching loss of the switching device.

[0057] The drive end, input end, and output end corresponding to different types of switching devices are different. For example, taking the switching device as a triode, the drive end is the base, the input end can be the collector, and the output end can be the emitter. In addition, the input end and output end of the triode can also be reversed, depending on the type of the triode. Taking the switching device as a MOS transistor, the drive end can be the gate, the input end can be the drain, and the output end can be the source. In addition, the input end and output end of the MOS transistor can also be reversed, depending on the type of the MOS transistor.

[0058] The above four control strategies (Strategy 1, Strategy 2, Strategy 3, Strategy 4) can be adopted simultaneously, or at least one of them can be adopted. For example, in a possible implementation, a large drive current can be provided first in the turn-on stage to improve efficiency, then a small amplification factor can be adopted in the amplification stage to reduce the drive loss of the switching device, then the amplification factor of the switching device can be increased or the power supply to the drive end of the switching device can be stopped in the saturation stage, and the switching device can be turned off with a negative voltage in the turn-off stage to reduce the loss of the switching device.

[0059] The switching transistor in this application can be a single switching transistor or a composite transistor. Usually, a composite transistor includes two or more switching transistors. For example, the composite transistor can include a Darlington transistor or an IGBT transistor, and its schematic diagram is as Figure 3 shown. A Darlington transistor or an IGBT transistor usually includes two switching transistors, such as Figure 3 the high-power transistor S1 and the low-power transistor S2 in

[0060] When the above four strategies are adopted simultaneously, in a possible implementation manner, for a single switching transistor, its drive current waveform can be as Figure 4 shown. Figure 4 shows four different drive current waveforms, namely drive current waveform 1, drive current waveform 2, drive current waveform 3, and drive current waveform 4. Different drive current waveforms are different in at least one of the on stage, amplification stage, saturation stage, and off stage. Figure 4 Only a schematic diagram of stopping power supply to the drive end of the switching transistor in the saturation stage is shown. If the amplification factor of the switching transistor is increased in the saturation stage, then the waveform diagram in the saturation stage will be different from Figure 4 the waveform diagram in the saturation stage in Figure 1 Compared with the traditional drive waveform shown in Figure 1 , the drive waveform shown in this application can greatly reduce the loss of the switching transistor. Compared with Figure 1 , adopting the control strategy shown in this application makes the waveform of the corresponding waveband in the on stage, amplification stage, saturation stage, and off stage different from

[0061] When the above four strategies are adopted simultaneously, in a possible implementation manner, for a Darlington transistor or an IGBT transistor, its waveform principle is as Figure 5 shown. Figure 5 The solid line in Figure 3 represents the drive current waveform of the high-power transistor S1 in Figure 3 , and the dashed line represents the drive current waveform of the low-power transistor S2 in

[0062] Among them, in the amplification stage, the drive current of the switching transistor can be equal to the product of the input current of the switching transistor and the target amplification factor, and changes with the change of the input current of the switching transistor. For example, when the input current increases, the drive current increases; when the input current decreases, the drive current decreases. In some possible implementation manners, the input current can also be replaced by the output current. At this time, the drive current can be equal to the product of the output current of the switching transistor and another fixed target amplification factor.

[0063] If the switching transistor is a single switching transistor, the target magnification factor is less than or equal to 7.5 times; if the switching transistor is a composite transistor, such as a Darlington transistor, the target magnification factor is less than or equal to 56 times. Usually for a switching transistor, the magnification factor of a switching transistor driven by the traditional method is above 7.5 times. In order to reduce the driving loss of the switching transistor in the embodiments of the present application, a magnification factor less than 7.5 times is adopted to reduce the driving current. Taking the switching transistor as a triode as an example, in the embodiments of the present application, the magnification factor is equal to IC / IB and less than 7.5, where IC represents the collector current of the triode and IB represents the base current of the triode.

[0064] In some possible implementation manners, the target magnification factor is a single fixed magnification factor and remains unchanged in different control cycles; in some other possible implementation manners, the target magnification factor can be different in different control cycles.

[0065] In addition, the target magnification factor in the above amplification stage can be related to the parameters of the switching transistor, where the parameters include at least one of the temperature of the circuit where the switching transistor is located, the input terminal peak current (Instantaneous Peak Current, IPK) of the switching transistor, and the input voltage of the switching transistor. The corresponding relationship between different parameters and the target magnification factor can be established in advance. When selecting the target magnification factor subsequently, the target magnification factor corresponding to the parameter can be selected according to this corresponding relationship, and the target magnification factors corresponding to different parameters can be different. Usually, the target magnification factor is positively correlated with the above temperature and input voltage parameters and negatively correlated with the IPK peak current. Here, only taking the case where the above temperature, IPK peak current, and input voltage are included at the same time as an example, generally: the lower the temperature, the lower the input voltage, and the larger the IPK peak current, the smaller the target magnification factor.

[0066] In the saturation stage, the magnification factor of the switching transistor can be increased, or the power supply to the driving end of the switching transistor can be stopped. In some possible implementation manners, in the saturation stage, the magnification factor of the switching transistor or the time when the power supply to the driving end of the switching transistor is stopped (which can be considered as the time ratio of the saturation stage) is also related to the parameters of the switching transistor. Different parameters increase different magnification factors, or the time when the power supply to the driving end of the switching transistor is stopped corresponding to different parameters is different. Usually, the magnification factor is positively correlated with the above temperature and input voltage parameters and negatively correlated with the IPK peak current. The time when the power supply to the driving end is stopped is positively correlated with the above temperature and input voltage parameters and negatively correlated with the IPK peak current. For example, the lower the temperature, the lower the input voltage, and the larger the IPK peak current, the shorter the time when the power supply to the driving end is stopped, that is, the time ratio of the saturation stage is reduced. The corresponding relationship between different parameters and the time when the power supply to the driving end is stopped can be established in advance. When selecting the time when the power supply to the driving end is stopped subsequently, the time when the power supply to the driving end is stopped corresponding to the parameter can be selected according to this corresponding relationship.

[0067] During the saturation stage, increasing the amplification factor of the switching transistor may include: increasing the amplification factor of the switching transistor by using any one of the following methods: Method 1: Simultaneously increase the input current and the drive current of the switching transistor, and the increase amplitude of the drive current is less than that of the input current.

[0068] Method 2: Increase the input current of the switching transistor, and keep the drive current of the switching transistor unchanged.

[0069] Method 3: Increase the input current of the switching transistor and decrease the drive current of the switching transistor.

[0070] During the turn-off stage, when turning off the switching transistor with a negative voltage, the process includes: first stopping power supply to the drive end of the switching transistor, and then pulling down the voltage of the drive end of the switching transistor to be less than the voltage of the output end of the switching transistor. Taking the switching transistor as a triode as an example, first stop power supply to the base of the switching transistor, and then pull down the base voltage of the switching transistor to be less than the emitter voltage of the switching transistor. The greater the amplitude of pulling down the drive-end voltage, the faster the turn-off speed of the switching transistor. In a possible implementation, the drive end of the switching transistor can be grounded through a first switch, and during the turn-off stage, the drive-end voltage can be pulled down by turning on this switch.

[0071] During the turn-off stage, when turning off the switching transistor with a negative voltage, the process includes: first raising the voltage of the output end of the switching transistor, and then discharging the voltage of the drive end of the switching transistor. Taking the switching transistor as a triode as an example, first raise the emitter voltage of the switching transistor, and then discharge the base voltage of the switching transistor.

[0072] In a possible implementation, the drive end of the switching transistor can be grounded through a third switch (such as Figure 6 switch S4 in Figure 6 ), the output end of the switching transistor is grounded through a first switch (such as Figure 6 switch S3 in Figure 6 ), and its schematic diagram is as shown in Figure 6 . Figure 6 In Figure 6 , the base of the triode is grounded through switch S4, and the emitter of the triode is grounded through switch S3. During the turn-off stage, the emitter voltage can be raised by turning off switch S3, and then the base voltage can be discharged by turning on switch S4. Among them, in Figure 6 and subsequent diagrams, only the switching transistor is taken as a triode for example. Therefore, the switching transistor being a triode should not be understood as a limitation to this application.

[0073] If the switching transistor is a composite transistor, for example, the composite transistor may include a Darlington transistor or an IGBT transistor. If the switching transistor is Figure 3For the structure shown, when turning off the switching transistor under negative pressure, the process includes: first discharging the driving-end voltage of the low-power transistor S2 in the composite transistor, and then discharging the driving-end voltage of the high-power transistor S1 in the composite transistor; or, first discharging the driving-end voltage of the low-power transistor S2 in the composite transistor, then raising the output-end voltage of the high-power transistor S1 in the composite transistor, and then discharging the driving-end voltage of this high-power transistor S1.

[0074] In a possible implementation, the driving end of the switching transistor can be grounded through a third switch (such as Figure 7 the switches S4 and S5 in Figure 7 ), and the output end of the switching transistor is also grounded through a first switch (such as Figure 7 the switch S3 in Figure 7 ). The schematic diagram is as shown in Figure 7 . In the turn-off stage, the switch S5 can be turned on first to discharge the driving-end voltage of the low-power transistor S2, then the switch S3 is turned off to raise the output-end voltage of the high-power transistor S1 in the composite transistor, and then the switch S4 is turned on to discharge the driving-end voltage of the high-power transistor S1.

[0075] In some possible implementations, the output end of the switching transistor can also be grounded through a capacitor VCC. In addition, a first diode and / or a second switch can be connected in series between the output end of the switching transistor and the capacitor. For example, the output end of the switching transistor is connected to the capacitor through a first diode, or the output end of the switching transistor is connected to the capacitor through a first diode and a second switch connected in parallel. The specific schematic diagrams are as shown in Figure 8a 、 Figure 8b 、 Figure 8c . Figure 8a In Figure 8a 、 Figure 8b 、 Figure 8c , the emitter of the switching transistor S1 is connected to the capacitor through a first diode (i.e., the diode D1 in the figure), In Figure 8b , the emitter of the switching transistor S1 is connected to the capacitor through a second switch (i.e., the switch S6 in the figure), In Figure 8c , the emitter of the switching transistor S1 is connected to the capacitor through a diode D1 and a switch S6 connected in parallel. In this implementation, the above control method further includes: in the saturation stage, controlling the duration of the turn-off of the switch S3 according to the power supply demand of the capacitor, where when the switch S3 is turned off, the switching transistor S1 charges the capacitor. When charging the capacitor, for Figure 8b , when the switch S3 is turned off, the switch S6 is in the on state; for Figure 8c , when the switch S3 is turned off, the switch S6 is in the off state. By charging the capacitor in the saturation stage, it is convenient for the capacitor to discharge the switching transistor S1 in the turn-off stage, providing a reverse current from the driving end to the output end for the switching transistor S1.

[0076] Among them, when charging the capacitor, the charging control can be divided into the following stages according to the power supply demand of the capacitor: Stage 1: When the power supply demand of the capacitor is insufficient, supply power to the capacitor with the maximum power, or supply power to the capacitor with a power greater than the power consumed by the capacitor; Stage 2: When the power supply to the capacitor is excessive, supply power to the capacitor with a power less than the power consumed by the capacitor, thereby solving the problem of insufficient and / or excessive VCC power supply. Among them, in addition to being used to accelerate the closing speed, the first switch is also used to supply power to the capacitor VCC to solve the problem of insufficient and / or excessive VCC power supply. By controlling the conduction or cut-off duration of the first switch, the charging control of different stages can be achieved. For example, when the power supply demand is insufficient, extend or advance the cut-off duration of the first switch.

[0077] In the turn-off stage, the power supply to the driving end of the switching transistor will be stopped. At this time, the capacitor discharges to the switching transistor, providing a reverse current from the driving end to the output end of the switching transistor. If the output end of the switching transistor is also connected to the capacitor through a parallel-connected first diode and a second switch (schematic diagram as Figure 8c shown), or the output end of the switching transistor is connected to the capacitor through a second switch (schematic diagram as Figure 8b shown), the above control method further includes: in the turn-off stage, control the second switch (i.e., switch S6) to conduct and the first switch (i.e., switch S3) to cut off, so that the capacitor provides a reverse current from the driving end to the output end of the switching transistor, accelerating the extraction of the charge of the B pole (base), and improving the turn-off speed.

[0078] In some possible implementation manners, as Figure 9 shown, the driving end of the switching transistor is connected to a current mirror (including MOS transistor S7, MOS transistor S8, reference current source Iref) through a second diode (such as Figure 9 the diode D2 in) or a MOS transistor (the diode D2 in Figure 9 can be replaced by a MOS transistor). At this time, the above control method further includes: in the saturation stage, when the voltage of the driving end of the switching transistor is greater than a preset voltage (configurable), gradually increase the current of the current mirror to reduce the conduction voltage difference of the current mirror. For example, when the VB voltage (i.e., the base voltage) is higher than a certain voltage, the conduction voltage difference of MOS transistor S8 can be reduced by gradually increasing the current of the reference current Iref in the current mirror according to the increase of the VB voltage, and / or Figure 9 replace the diode D2 in with a MOS transistor to reduce the conduction voltage difference to improve the driving ability.

[0079] The principle is as follows: When the drive current is very large, the pressure difference across the entire loop is very high. For example, when driving an IC current of 2A and amplifying it by 5 times, a drive current of 0.4A is required. At this time, if the internal resistance of switch S3 is 0.3Ω (ohm), the required drive voltage is: the conduction pressure difference of switch S3, 0.72V + the VBE voltage of switch transistor S1, 3V + the pressure difference of diode D2, 0.8V + the pressure difference of MOS transistor S8, 1V = 5.52V. And the power supply range of capacitor VCC is usually 3.3 - 5V, so the driving ability is insufficient. Usually, the conventional operation is to increase the area of switch transistor S1 to reduce the VBE voltage (the voltage difference between base B and emitter E), but this is too costly. In this application, by increasing the reference current Iref of the current mirror, the driving pressure difference of MOS transistor S8 is increased, thereby reducing the on-resistance of MOS transistor S8 and its conduction pressure difference to increase the driving ability. Replacing diode D2 with a MOS transistor follows the same principle.

[0080] Among them, Figure 9 the current mirror (including MOS transistor S7, MOS transistor S8, reference current source Iref), diode D2, diode D1, capacitor VCC, switch S4, switch S3, etc. belong to the electronic components of the control circuit. In addition, the control circuit can also include a controller, etc.

[0081] The above first switch, second switch, and third switch can be switch transistors. For example, they can be triode switches or MOS transistor switches, etc. In addition, the above first switch, second switch, and third switch can also be other intelligent switches, such as relays, etc.

[0082] To better understand the effect of the control method shown in this application compared with the conventional square wave control, the following is illustrated with examples. Assume that a conventional triode has an amplification factor of 8 times, IPK is a current of 1A, and the conduction time is 3S. Then the required driving charge quantity is: (1A / 8 times) × 3S / 2 = 0.1875 coulombs. If the driving method of this application is adopted and the power supply is turned off at the 2 / 3 position (it can be earlier or later), at this time, the conduction time is 2S, even with an amplification factor of 5 times (it can be smaller). Then the driven IPK current is (1A × 2 / 3) / 5 = 0.133A, and the required driving charge quantity is: 0.133A × 2S / 2 = 0.133 coulombs. It can be seen that adopting the driving method shown in this application, the driving charge is reduced by 30% compared with the full-drive method. Since the driving charge is reduced, the corresponding driving voltage will also be reduced. At the same time, the conduction voltage drop can also be reduced after the amplification factor is reduced. Through the accelerated turn-off method, the turn-off time of the conventional VCE (the voltage difference between collector C and emitter E) needs to be more than 120nS, while through this scheme, the turn-off time is shortened to within 100nS, reducing the switching loss.

[0083] An embodiment of the present application further provides a switching transistor driving device, which includes a switching transistor and a control circuit. The control circuit is connected to the driving end of the switching transistor and is configured to provide a control strategy including multiple stages and control the switching transistor by using the control strategy to reduce the loss of the switching transistor, where the control strategies corresponding to at least two of the multiple stages are different.

[0084] In some possible implementation manners, the control circuit includes: a capacitor, a first switch, and a first diode and / or a second switch. For the schematic diagram, refer to the above Figure 8a , Figure 8b , Figure 8c . The output end of the switching transistor is grounded through the first switch, the output end of the switching transistor is grounded through the capacitor, and a first diode and / or a second switch is further arranged between the output end of the switching transistor and the capacitor. In the turn-on stage and the amplification stage, the first switch is turned on. In the turn-off stage, the first switch is turned off. In the saturation stage, the conduction or turn-off of the first switch is controlled according to the power supply requirement of the capacitor; when the first switch is turned off, the switching transistor is used to charge the capacitor.

[0085] In some possible implementation manners, if the output end of the switching transistor is connected to the capacitor through the first switch, at this time, the schematic diagram is as shown in the above Figure 8b , Figure 8c . In the turn-off stage, the first switch is in the off state and the second switch is in the on state, and the capacitor provides a reverse current from the driving end to the output end of the switching transistor.

[0086] In some possible implementation manners, the control circuit further includes a third switch (such as the switch S4 in Figure 8a , Figure 8b , Figure 8c ), and the driving end of the switching transistor is further grounded through the third switch. In the turn-off stage, the third switch is in the on state. In other states, the third switch is in the off state.

[0087] In some possible implementation manners, the control circuit further includes: a controller and a current mirror (including the MOS transistor S7, the MOS transistor S8, and the reference current source Iref in Figure 9 ). The driving end of the switching transistor is connected to the current mirror through a diode D2 or a MOS transistor. In the saturation stage, when the voltage at the driving end of the switching transistor is greater than a preset voltage, the controller is configured to gradually increase the current of the current mirror to reduce the conduction voltage difference of the current mirror.

[0088] Wherein, for the schematic connection diagram between the control circuit and the switching transistor, reference can be made to Figure 9 shown. The current mirror (including the MOS transistor S7, the MOS transistor S8, and the reference current source Iref), the diode D2, the diode D1, the capacitor VCC, the switch S4, the switch S3, etc. in Figure 9 all belong to the electronic components of the control circuit.

[0089] In addition, the controller is further configured to control the conduction or cutoff of the first switch (such as switch S3), the second switch (such as switch S6), and the third switch (such as switch S4 and switch S5), and is further configured to adjust the current of the current mirror.

[0090] The controller may be an integrated circuit chip with signal processing capabilities. The above-mentioned controller may be a processor, and the processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), a graphics processing unit (GPU), an accelerated processing unit, a multimedia application processor (MAP), a microprocessor, etc.; it may also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. Or the controller may also be any conventional processor, etc.

[0091] The switch tube driving device provided by the embodiments of the present application can be applied to various switch circuits to achieve the control of the cutoff or conduction of the switch tube. For example, it can be applied to various converters, such as flyback converters. The implementation principle and the technical effects generated by the switch tube driving device provided by the embodiments of the present application are the same as those of the foregoing method embodiments. For the sake of brief description, for the parts not mentioned in the embodiments of the switch tube driving device, reference may be made to the corresponding contents in the foregoing method embodiments. The embodiments of the present application further provide an electronic device, which may be an electronic device including the above-mentioned switch tube driving device. For example, the electronic device may be various electronic devices such as a mobile phone, a tablet computer, and a computer.

[0092] It should be noted that the embodiments in this specification are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0093] In several embodiments provided by this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of devices, methods, and computer program products according to multiple embodiments of this application. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the part of the module, program segment, or code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0094] In addition, the functional modules in each embodiment of this application can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0095] As described above, the above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A control method for a switching tube, characterized in that, Including: Providing a multi-stage control strategy and using the control strategy to control the switching transistor to reduce the loss of the switching transistor; Among them, at least one stage in the multi-stage adopts a control strategy different from a square wave.

2. The control method according to claim 1, wherein The multi-stage includes a turn-on stage, an amplification stage, a saturation stage, and a turn-off stage; Using the control strategy to control the switching transistor includes: using at least one of the following control strategies to control the switching transistor: Strategy 1: In the turn-on stage, driving the switching transistor with a driving current greater than the starting current of the amplification stage to accelerate the turn-on of the switching transistor; Strategy 2: In the amplification stage, driving the switching transistor with a driving current positively correlated with the product of the input current of the switching transistor and the target amplification factor to reduce the driving loss of the switching transistor; Strategy 3: In the saturation stage, increasing the amplification factor of the switching transistor or stopping power supply to the driving end of the switching transistor; Strategy 4: In the turn-off stage, turning off the switching transistor with a negative voltage to accelerate the turn-off speed of the switching transistor.

3. The control method according to claim 2, wherein Turning off the switching transistor with a negative voltage includes: First stopping power supply to the driving end of the switching transistor, and then pulling down the voltage of the driving end of the switching transistor to be less than the output voltage of the switching transistor; or, First raising the output voltage of the switching transistor, and then discharging the voltage of the driving end of the switching transistor.

4. The control method according to claim 2, wherein The switching transistor is a composite transistor, and the composite transistor includes a Darlington transistor or an IGBT transistor. Turning off the switching transistor with a negative voltage includes: First discharging the voltage of the driving end of the low-power transistor in the composite transistor, and then discharging the voltage of the driving end of the high-power transistor in the composite transistor; or, First discharging the voltage of the driving end of the low-power transistor in the composite transistor, then raising the output voltage of the high-power transistor in the composite transistor, and then discharging the voltage of the driving end of the high-power transistor.

5. The control method according to claim 2, wherein In the amplification stage, the target amplification factor is related to the parameters of the switching transistor; and / or; in the saturation stage, the amplification factor of the switching transistor or the time for stopping power supply to the driving end of the switching transistor is related to the parameters of the switching transistor; Among them, the parameters include at least one of the temperature of the circuit where the switching transistor is located, the peak input current of the switching transistor, and the input voltage of the switching transistor.

6. The control method according to claim 2, wherein Increasing the amplification factor of the switching transistor in the saturation stage includes: using any one of the following methods to increase the amplification factor of the switching transistor: Method 1: Simultaneously increasing the input current and the driving current of the switching transistor, and the increase amplitude of the driving current is less than the increase amplitude of the input current; Method 2: Increasing the input current of the switching transistor, and the driving current of the switching transistor remains unchanged; Method 3: Increasing the input current of the switching transistor and decreasing the driving current of the switching transistor.

7. The control method according to claim 2, wherein The output end of the switch tube is grounded via a first switch, the output end of the switch tube is also grounded via a capacitor, and a first diode and / or a second switch are further provided between the output end of the switch tube and the capacitor; the method further includes: In the saturation stage, the duration of the first switch being turned off is controlled according to the power supply demand of the capacitor, wherein the switch tube charges the capacitor when the first switch is turned off.

8. The control method according to claim 7, wherein The output end of the switch tube is connected to the capacitor via a second switch, and the method further includes: In the closing phase, the first switch is controlled to be turned off and the second switch is controlled to be turned on, so that the capacitor provides a reverse current from the driving end to the output end of the switch tube.

9. The control method according to claim 2, wherein The driving end of the switch tube is connected to the current mirror via a second diode or a MOS tube, and the method further includes: In the saturation stage, when the driving terminal voltage of the switch tube is greater than a preset voltage, the current of the current mirror is gradually increased to reduce the conduction voltage difference of the current mirror.

10. A switching transistor driving device, characterized in that, include: Switching tube; A control circuit connected to the driving end of the switch tube, the control circuit being used to provide a control strategy including multiple stages and use the control strategy to control the switch tube to reduce the loss of the switch tube; Among the multiple stages, at least one stage adopts a control strategy different from the square wave.

11. The switching transistor driving device according to claim 10, wherein The control circuit includes: a capacitor, a first switch, and a first diode and / or a second switch. The output end of the switch tube is grounded via the first switch, and the output end of the switch tube is also grounded via the capacitor. A first diode and / or a second switch is further provided between the output end of the switch tube and the capacitor. The multiple stages include an opening stage, an amplification stage, a saturation stage and a closing stage; In the start-up phase and the amplification phase, the first switch is turned on, in the shut-down phase, the first switch is turned off, and in the saturation phase, the first switch is controlled to be turned on or off according to the power supply demand of the capacitor; When the first switch is turned off, the switch tube is used to charge the capacitor.

12. The switching transistor driving device according to claim 11, wherein, The output end of the switch tube is connected to the capacitor through a second switch; In the closing stage, the first switch is in an off state, the second switch is in an on state, and the capacitor provides a reverse current from the driving end to the output end of the switch tube.

13. The switching transistor driving device according to claim 11, wherein, The control circuit further includes: a third switch, and the driving end of the switch tube is also grounded via the third switch; In the closing phase, the third switch is in an on state.

14. The switching tube driving device according to any one of claims 11-13, characterized in that, The control circuit comprises: a controller and a current mirror, and the driving end of the switch tube is connected to the current mirror through a second diode or a MOS tube; In the saturation stage, when the driving terminal voltage of the switch tube is greater than a preset voltage, the controller is used to gradually increase the current of the current mirror to reduce the conduction voltage difference of the current mirror.

15. An electronic device, characterized in that, include: A switch tube driving device as claimed in any one of claims 10 to 14.

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