Power device control method and current source

Abstract

The present application relates to a control method and current source for a power device. In a control method for controlling the conduction of a power device using a current source, the current source first outputs a first current to precharge the gate of the power device, causing the gate voltage of the power device to reach a first threshold voltage, at which point it is about to enter the Miller platform. The current source then outputs a relatively small second current to charge the gate of the power device until the gate voltage meets the set drive voltage requirement, suppressing the rate of change of the drain-source voltage and avoiding electromagnetic interference. The shutdown process follows this approach for segmented control. Through this precise segmented control, different drive currents are provided to the gate in each segment, which not only reduces the switching cycle, i.e., reduces switching losses, but also ensures anti-electromagnetic interference effects. Furthermore, this control implementation does not require additional hardware devices such as dv / dt or di / dt detection circuits, resulting in low cost and not being restricted by the hardware circuit framework, with strong adaptability and flexibility.

Description

Technical Field

[0001] The present application relates to the technical field of switch drive control, and in particular to a control method and current source for a power device. Background Art

[0002] With the rise of the new energy technology revolution, more and more industries are undergoing electrification, with power supply and powertrain being the primary drivers. This is particularly true for new energy technologies such as electric vehicles and charging stations (including AC / DC and wireless charging stations). These industries all face challenges in controlling the gate drive of power devices. During the power device driving process, switching losses and electromagnetic interference during turn-on and turn-off have long been hot research topics.

[0003] During implementation, the inventors discovered that conventional technologies often induce electromagnetic interference (EMI) when reducing switching losses. Furthermore, addressing EMI requires suppressing the rate of change of drain-source voltage or drain current, which lengthens the switching cycle and increases switching losses. Reducing switching losses without inducing EMI is a key issue in this field. Summary of the Invention

[0004] Based on this, it is necessary to provide a control method and current source for power devices that can effectively shorten the switching period, that is, reduce switching losses, while suppressing electromagnetic interference to address the above technical problems.

[0005] In one aspect, an embodiment of the present application provides a method for controlling a power device, which is applied to a current source to control the conduction of the power device. The method includes:

[0006] The current source outputs a first current to precharge the gate of the power device so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device;

[0007] After the gate voltage of the power device reaches the first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device;

[0008] The effective value of the first current is greater than the effective value of the second current.

[0009] In one embodiment, the current source is a constant current source, and the first current is greater than the second current.

[0010] In one embodiment, the step of “after the gate voltage of the power device reaches the first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement” includes:

[0011] From the time when the gate voltage of the power device reaches the first threshold voltage to the end of the Miller platform, the current source outputs a second current to charge the gate of the power device;

[0012] After the Miller platform ends, the current source outputs a third current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement;

[0013] The effective value of the third current is greater than the effective value of the second current.

[0014] In one embodiment, the step of determining the end of the Miller platform includes:

[0015] If the gate voltage of the power device reaches the second threshold voltage, it is determined that the Miller plateau ends, and the second threshold voltage is greater than the first threshold voltage.

[0016] In one embodiment, the current source is a constant current source, and the third current is greater than the second current.

[0017] In one embodiment, the power device control method further includes:

[0018] The current source configures the first current and / or the second current and / or the third current in each switching cycle.

[0019] On the other hand, an embodiment of the present application further provides a method for controlling a power device, which is applied to a current source to control the shutdown of the power device. The method includes:

[0020] The current source outputs a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device;

[0021] After the gate voltage of the power device drops to a third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device;

[0022] The effective current value of the fourth current is greater than the effective current value of the fifth current.

[0023] In one embodiment, the current source is a constant current source, and the fourth current is greater than the fifth current.

[0024] In one embodiment, the step of “after the gate voltage of the power device drops to the third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged” includes:

[0025] From the time when the gate voltage of the power device drops to the third threshold voltage until the Miller platform ends, the current source outputs a fifth current to discharge the gate of the power device;

[0026] After the Miller platform ends, the current source outputs a sixth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged;

[0027] The effective current value of the sixth current is greater than the effective current value of the fifth current.

[0028] In one embodiment, the step of determining the end of the Miller platform includes:

[0029] If the gate voltage of the power device drops to the fourth threshold voltage, it is determined that the Miller plateau ends, and the fourth threshold voltage is less than the third threshold voltage.

[0030] In one embodiment, the current source is a constant current source, and the sixth current is greater than the fifth current.

[0031] In one embodiment, the power device control method further includes:

[0032] The current source configures the fourth current and / or the fifth current and / or the sixth current in each switching cycle.

[0033] An embodiment of the present application also provides a power device control method, which is applied to a current source to control the on and off of a power device. The method includes the above-mentioned power device control method applied to a current source to control the on-state of a power device and the power device control method applied to a current source to control the off-state of a power device.

[0034] In addition, the present application also provides a current source, the output end of the current source is used to connect to the gate of the power device, and the current source is used to execute the steps of the power device control method applied to the current source to control the power device to be turned on, and / or the steps of the power device control method applied to the current source to control the power device to be turned off.

[0035] In one embodiment, the current source includes a control module and an output module, the control module is electrically connected to the output module, and the output module is used to inject current into the gate of the power device;

[0036] The control module includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it implements the steps of the above-mentioned control method for a power device applied to control the conduction of the power device, and / or the steps of the above-mentioned control method for a power device applied to control the shutdown of the power device.

[0037] In one embodiment, the current source includes a control module and an output module, the control module is electrically connected to the output module, and the output module is used to inject current into the gate of the power device;

[0038] The control module includes a timer, which is used to control the conduction of the power device. The timer is configured as follows:

[0039] Outputting a first electrical signal in a first segment time, the first electrical signal being used to drive the output module to output a first current to pre-charge the gate of the power device, the first segment time being a time period in which the gate voltage of the power device reaches a first threshold voltage;

[0040] After the first segment time, a second electrical signal is output, where the second electrical signal is used to drive the output module to output a second current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement;

[0041] and / or,

[0042] The timer is used to control the shutdown of the power device. The timer is configured as follows:

[0043] Outputting a third electrical signal in a second segment time, the third electrical signal is used to drive the output module to output a fourth current to discharge the gate of the power device, the second segment time being a time period during which the gate voltage of the power device drops to a third threshold voltage;

[0044] After the second segment time, a fourth electrical signal is output, and the fourth electrical signal is used to drive the output module to output a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged.

[0045] One or more embodiments provided by the embodiments of the present application have at least the following beneficial effects: In the control method of the power device provided by the embodiments of the present application, the current source inputs currents of different properties in segments during each switching cycle of the power device. When driving the power device to turn on, the first current is used to pre-charge the power device, so that the gate voltage VGS rises rapidly, shortening the switching time of the power device. At the same time, in order to prevent the electromagnetic interference problem caused by the rapid change of the drain-source voltage, when the gate voltage reaches the first threshold voltage, that is, electromagnetic interference may be generated at this time, by changing the output current, a second current with a smaller effective value is used to suppress the rapid change of the drain-source voltage. Through precise segmented control, the power loss during the conduction process of the power device is reduced, and the generation of electromagnetic interference is prevented.

[0046] Similarly, in the shutdown control of the power device, a similar idea is adopted. At the initial stage of the shutdown control, the current source outputs a larger fourth current to accelerate the gate discharge process, and when the gate voltage drops to the third threshold voltage, it outputs a fifth current with a smaller effective value than the fourth current to suppress the rapid change of the drain-source voltage. Through this precise segmented control, the overall on-off switching cycle of the power device is shortened, that is, the switching loss is reduced, and the anti-EMI (Electromagnetic Interference) effect is guaranteed.

[0047] In addition, the control method of the power device provided in the embodiment of the present application does not require additional hardware devices such as dv / dt (drain-source voltage change rate) or di / dt (drain current change rate) detection circuits. In the application, the first threshold voltage and the third threshold voltage are configured according to the typical gate characteristics and the switching voltage waveform of the power device used, as well as the charging / discharging current source under each segment during the on / off process. Different segments can be distinguished by comparing the magnitude relationship between the gate voltage and the reference voltage (first threshold voltage / third threshold voltage) through a voltage comparator built into or external to the current source. Subsequently, the charging / discharging current source is enabled for each segment time, and the driving current source outputs charging and discharging currents of different sizes in the corresponding time period to drive the switch of the power device to turn on or off. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of the conduction process of a power device MOSFET;

[0049] Figure 2 A schematic diagram of the turn-off process of a power device MOSFET;

[0050] Figure 3 A schematic diagram of a solution for improving electromagnetic interference problems in an exemplary technology;

[0051] Figure 4 1 is a flow chart of a method for controlling a power device in which a current source controls conduction of the power device according to an embodiment;

[0052] Figure 5 A schematic diagram of changes in voltage and current of a power device and a schematic diagram of changes in a driving current output by a current source during implementation of a method for controlling a power device in which a current source controls conduction of the power device in one embodiment;

[0053] Figure 6A schematic diagram of changes in voltage and current of a power device and a schematic diagram of changes in a driving current output by a current source during implementation of a method for controlling a power device in which a current source controls conduction of the power device in another embodiment;

[0054] Figure 7 1 is a flow chart of a method for controlling a power device in which a current source controls conduction of the power device in another embodiment;

[0055] Figure 8 A schematic diagram of changes in voltage and current of a power device and a schematic diagram of changes in a driving current output by a current source during implementation of a method for controlling a power device in which a current source controls conduction of the power device in another embodiment;

[0056] Figure 9 1 is a flow chart of a method for controlling a power device in which a current source is used to control the shutdown of the power device in one embodiment;

[0057] Figure 10 1 is a flow chart of a method for controlling a power device in which a current source is used to control the shutdown of the power device in another embodiment;

[0058] Figure 11 A structural block diagram of a control device for a power device in which a current source is used to control conduction of the power device in one embodiment;

[0059] Figure 12 1. A structural block diagram of a control device for a power device in which a current source is used to control the shutdown of the power device in one embodiment;

[0060] Figure 13 Schematic diagram of the internal structure of a current source in one embodiment;

[0061] Figure 14 is a schematic diagram of the specific structure of a current source in yet another embodiment;

[0062] Figure 15 is a schematic diagram of the specific structure of a current source in another embodiment;

[0063] Figure 16 FIG. 4 is a schematic diagram of a specific structure of a current source in yet another embodiment. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0065] like Figure 1As shown in the figure, the conduction process of the power device MOSFET (Metal-Oxide-Semiconductor Field-EffectTransistor) is taken as an example. The conduction process is divided into four stages. In the stage t0 to t1: the gate voltage V GS From 0V to its gate turn-on threshold voltage V th t1~t2 stage: gate voltage V GS From its gate turn-on threshold voltage V th To Miller Region voltage V Miller , drain current I DS Rising stage. t2~t3 stage: gate voltage V GS During the Miller platform period, the voltage V DS Falling stage. t3~t4 stage: gate voltage V GS From the Miller platform voltage V Miller Rising to the supply voltage stage, further reducing the conduction V DS pressure drop.

[0066] The shutdown process of the power device is as follows Figure 2 As shown, it is the opposite process of the conduction process.

[0067] By increasing the dv / dt (drain-source voltage change rate) at the moment of turning on or off, the switching time of the power switch can be shortened. The drain-source voltage Vds and its drain current I DS The overlapping area is reduced, and the switching loss per cycle is reduced, but the EMI (Electromagnetic Interference) problem caused by this needs to be considered; if the drain-source voltage change rate dv / dt is reduced, the switching time of the power device is prolonged, and its drain-source voltage V DS Its drain current I DS The increased overlap area increases the switching loss per cycle, but makes EMI easier to handle. In practical applications, the main factor affecting EMI is dv / dt.

[0068] In order to solve the EMI problem, the common solution is as follows Figure 3 The exemplary technical solution shown, by configuring an external gate resistor Rg, indirectly adjusts the gate charging current in the t2-t3 stage (the discharge current during the shutdown process), thereby achieving the purpose of reducing dv / dt (drain-source voltage change rate) and improving EMI (Electromagnetic Interference).

[0069] However, during implementation, the inventors discovered that while the solution in the exemplary technology alleviated EMI issues, it also indiscriminately prolonged the other three time periods, resulting in increased switching cycles and switching losses. Furthermore, the exemplary technology requires the use of gate resistor Rg, which increases costs and often requires an external detection circuit to adjust the current limiting of gate resistor Rg by monitoring the voltage and current characteristics of the power device, further increasing hardware costs and circuit complexity. It is desirable to provide a method for gate drive control of power device switches that addresses EMI by controlling the drain-source voltage change rate dv / dt, thereby complying with relevant regulations and shortening product time to market. This method also reduces switching losses and shortens the switching cycle.

[0070] Based on this, in order to solve the above problems, the embodiment of the present application provides a control method for a power device, which is applied to a current source to control the conduction of the power device, such as Figure 4 As shown, the method includes:

[0071] S200: The current source outputs a first current to pre-charge the gate of the power device, so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device;

[0072] S400: After the gate voltage of the power device reaches a first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device;

[0073] The effective value of the first current is greater than the effective value of the second current.

[0074] A current source is a circuit that can output at least two different drive currents. The current source can be an integrated body of multiple current sources, for example, the current source can be a transistor saturation characteristic current source, a multi-channel current source composed of multiple constant current sources, and a voltage controlled current source (VCCS). The set drive voltage requirement refers to an appropriate gate voltage so that when the power device is turned on, its V DS The conduction voltage drop between them is relatively low. For example, for MOSFET, the usual driving voltage is 12V, and for IGBT, the usual driving voltage is 15V. Miller platform voltage refers to the gate voltage of the power device when it enters the Miller platform stage. Figure 5It can be seen that if there is no interference during the duration of the Miller platform, the rate of change of the drain-source voltage when it just enters the Miller platform will be too large, the rate of change of the generated magnetic field will be greater, the electromotive force induced in the surrounding conductors will be higher, and it will be more likely to generate electromagnetic interference. Therefore, the purpose of the second current is to suppress the rate of change of the drain-source voltage of the power device and keep the rate of change of the drain-source voltage within a range that does not generate electromagnetic interference. The second current can be a constant value or a current function that changes with time. For example, during the time period when the drain-source voltage change rate of the power device itself is large, the second current value is set to a smaller value, and during the time period when the drain-source voltage change rate of the power device is small, the second current value can be appropriately increased to accelerate the end of the Miller platform without causing electromagnetic interference (such as Figure 5 As shown). As long as the first current and the second current of the switching period can be simultaneously shortened under the segmented scheme of the above method without causing electromagnetic interference compared to conventional technologies, they are within the scope of protection of this application.

[0075] Specifically, the present application uses a segmented control method based on a single threshold, and the current source inputs different currents in two stages during the gate charging process to achieve control of the drain-source voltage change rate dv / dt, thereby better solving the cycle loss and EMI problems of power devices in practical applications. Figure 5-6 As shown, in the I stage, that is, before the power device starts to charge until the gate voltage reaches the first threshold voltage, the current source outputs the first current I1 to pre-charge the gate until the gate voltage V GS Reaching the first threshold voltage V th1 In the second stage, when the gate voltage V GS After the first threshold voltage V th1 During the subsequent charging time, the gate is charged with the second current I2 until the gate voltage V GS reaches the supply voltage level.

[0076] Since electromagnetic interference is mainly caused by the drain-source voltage change rate dv / dt, the ideal first threshold voltage is set to the Miller platform voltage for the most accurate, which can ensure that the gate voltage is charged to the Miller platform voltage V quickly enough with a large first current. Miller However, in actual engineering practice, the change of drain-source voltage of power devices is affected by factors such as device operating temperature. Figure 1 Therefore, in order to improve the reliability of anti-EMI, the first threshold voltage can be set to a voltage value lower than the Miller platform voltage. That is, at the time point when the power device is about to enter the Miller platform stage but has not yet entered the Miller platform stage, the current source switches the output current from the first current to the second current to avoid the generation of EMI.

[0077] The first current I1 in stage I (before the gate voltage of the power device reaches the first threshold voltage) can be a constant current. Within each switching cycle, the first current I1 can be fixed (i.e., the first current within each switching cycle is the same) or configurable (the first current within different switching cycles can be different, for example, it can be set based on the voltage-current variation curve characteristics of the power device at different operating times). The second current I2 in stage II (the charging process after the gate voltage of the power device reaches the first threshold voltage) can also be configured. For example, as the operating time increases and the temperature of the power device increases, the drain-source voltage variation curve changes. Based on this change, the second current within each switching cycle can be configured.

[0078] The control method of the power device provided in the embodiment of the present application is that the current source inputs currents of different properties in each switching cycle of the power device in segments, and when driving the power device to turn on, the first current is used to pre-charge the power device so that the gate voltage V GS It rises quickly and shortens the switching time of power devices. At the same time, in order to prevent electromagnetic interference problems caused by rapid changes in drain-source voltage, when the gate voltage reaches the first threshold voltage, electromagnetic interference may be generated at this time. By changing the output current, a second current with a smaller effective value is used to suppress the rapid change of drain-source voltage. Through precise segmented control, the power loss during the conduction process of the power device is reduced, and the generation of electromagnetic interference is also prevented.

[0079] Furthermore, compared to conventional technologies, the control method provided by the embodiments of this application can achieve drain-source voltage rate of change (dv / dt) control for a given power device by configuring a single current source for gate charge and discharge, outputting a small constant current to the gate. This solution optimizes and controls the gate discharge process in stages, not only suppressing electromagnetic interference (EMI) issues but also shortening the overall switching cycle and reducing switching losses.

[0080] In one embodiment, the current source is a constant current source, and the current value of the first current output by the current source is greater than the current value of the second current. A constant current source can be selected, which outputs an ideal current that can maintain a fixed value for a certain period of time. For such a current source, ensuring that the current value of the first current is greater than the current value of the second current can achieve the purpose of accelerating charging in stage I and suppressing electromagnetic interference in stage II.

[0081] In one embodiment, Figure 7 As shown, the step of "after the gate voltage of the power device reaches the first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement" includes:

[0082] S420: From the time when the gate voltage of the power device reaches the first threshold voltage to the end of the Miller plateau, the current source outputs a second current to charge the gate of the power device;

[0083] S440: After the Miller platform ends, the current source outputs a third current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement;

[0084] The effective value of the third current is greater than the effective value of the second current.

[0085] Since the second current is smaller than the first current, after the Miller platform duration period (t3-t4 period), the drain-source voltage is stable, and there is no need to consider the electromagnetic interference problem caused by the rapid change of the drain-source voltage, such as Figure 8 As shown, at this time, the current source can further shorten the time of stages t3 and t4 by increasing the driving current output to the gate, that is, outputting a third current larger than the second current to charge the gate, thereby further reducing the conduction voltage drop and reducing the switching loss.

[0086] In addition, in engineering practice, when the gate voltage of the power device approaches the set driving voltage, the current of the current source will gradually drop to zero, such as Figure 8 In the third stage, the current source outputs a third current larger than the second current to charge the gate, which can shorten the t3-t4 period. As the gate voltage approaches the set drive voltage, the third current value output in the third stage also gradually decays to zero, ensuring that the gate voltage will not be charged to a value higher than the set drive voltage. Similarly, for Figure 6 In the two-stage control implementation scheme shown, the second current value output by the current source gradually decays to zero in stage II, ensuring that the gate voltage will not be charged to a value higher than the set driving voltage.

[0087] In one embodiment, the step of determining the end of the Miller platform includes:

[0088] If the gate voltage of the power device reaches a second threshold voltage, it is determined that the Miller plateau ends, and the second threshold voltage is greater than the first threshold voltage.

[0089] To further reduce switching losses in power devices while suppressing electromagnetic interference, the gate voltage at the point where a large current is applied to the gate without increasing the rate of change of the drain-source voltage to a level that causes electromagnetic interference can be selected as a second threshold voltage. When the gate voltage of the power device reaches this second threshold voltage, it indicates that a large current can be applied to the gate for gate drive, which not only accelerates the conduction process but also does not cause electromagnetic interference. This is defined as the end of the Miller platform. From this moment on, the current source outputs a larger third current for gate drive, accelerating the gate voltage to reach the set drive voltage. This reduces the switching period of the power device and further reduces switching losses.

[0090] In one embodiment, the current source is a constant current source, and the third current output by the current source has a current value greater than the second current. A constant current source can be selected, wherein the output current can be maintained at a fixed value for a certain period of time. For such a current source, ensuring that the third current has a current value greater than the second current can accelerate charging in Phase III, allowing the gate voltage to quickly reach the supply voltage level, shortening the conduction process of the power device, and further reducing switching losses.

[0091] In one embodiment, the control method of the power device further includes: a current source configuring the first current and / or the second current and / or the third current in each switching cycle.

[0092] Taking into account that the on-off characteristic parameter curve of the power device may be affected by factors such as temperature during operation, the driving current in each switching cycle of the power device, that is, part or all of the first current, second current, and third current mentioned above, can be configured according to the change of the drain-source voltage change curve of the selected power device with the operating time, so as to ensure that the switching loss and anti-EMI effect in each switching cycle can be optimized.

[0093] On the other hand, the embodiment of the present application also provides a method for controlling a power device, such as Figure 9 As shown, the method is applied to a current source to control the shutdown of a power device, and includes:

[0094] S600: the current source outputs a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device;

[0095] S800: After the gate voltage of the power device drops to a third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device;

[0096] The effective current value of the fourth current is greater than the effective current value of the fifth current.

[0097] For the shutdown control process of the power device, it is the reverse process of the above-mentioned power device conduction control. In the shutdown control of the power device, the current source outputs a larger negative polarity fourth current at the initial stage of the shutdown control to accelerate the gate discharge process, and when the gate voltage drops to the third threshold voltage, it outputs a fifth current whose effective value is smaller than the fourth current to suppress the rapid change of the drain-source voltage. Through this precise segmented control, it is ensured that the overall on-off switching cycle of the power device is shortened, that is, the switching loss is reduced, and the anti-EMI (Electromagnetic Interference) effect is guaranteed. Regarding the third threshold voltage, similar to the first threshold voltage, it is also a voltage value greater than or equal to the Miller platform voltage during the shutdown process. When the gate voltage drops to the third threshold voltage, the current source switches its output fourth current to a smaller fifth current to avoid electromagnetic interference caused by excessive changes in the drain-source voltage after the drain-source voltage begins to change, thereby reducing switching losses without causing EMI.

[0098] In one embodiment, the current source is a constant current source, and the fourth current output by the current source has a current value greater than the fifth current. The high-current fourth current is used to accelerate gate discharge and shorten the turn-off control time. After the gate voltage drops to a third threshold voltage, the current source switches to the smaller fifth current to discharge the gate, thereby avoiding electromagnetic interference caused by rapid changes in drain-source voltage. This ultimately reduces switching losses and achieves EMI mitigation.

[0099] In one embodiment, Figure 7 As shown, the step of “after the gate voltage of the power device drops to the third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged” includes:

[0100] S820: From the time when the gate voltage of the power device drops to the third threshold voltage until the Miller platform ends, the current source outputs a fifth current to discharge the gate of the power device;

[0101] S840: After the Miller platform ends, the current source outputs a sixth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged;

[0102] The effective current value of the sixth current is greater than the effective current value of the fifth current.

[0103] Similar to the reasons described in the embodiment of the power device conduction control method, in order to further reduce switching losses and shorten the time from the end of the Miller platform to the complete discharge of the gate, after the end of the Miller platform, the current source uses a sixth current that is larger than the fifth current to drive the gate to quickly and completely discharge.

[0104] In one embodiment, the step of determining the end of the Miller platform during the shutdown process of the power device includes:

[0105] If the gate voltage of the power device drops to the fourth threshold voltage, it is determined that the Miller plateau ends, and the fourth threshold voltage is less than the third threshold voltage.

[0106] Similar to the turn-on process of a power device, during its turn-off process, when the drain-source voltage remains essentially unchanged or changes at a very low rate, injecting a large drive current into the gate does not cause electromagnetic interference and can accelerate the turn-off process of the power device, thereby reducing switching losses. Therefore, the fourth threshold voltage indicates the gate voltage at which injecting a large current will not increase the rate of change of the drain-source voltage to a level that causes electromagnetic interference. By performing the above steps, when the gate voltage drops to the fourth threshold voltage, this moment can be defined as the end of the Miller platform. At this time, the current source outputs a large sixth current, accelerating the gate discharge process, thereby reducing the switching period of the power device and reducing switching losses.

[0107] In one embodiment, the current source is a constant current source, and the current value of the sixth current output by the current source is greater than the current value of the fifth current. The current source can be a constant current source, which outputs an ideal current that can maintain a fixed value for a certain period of time. For such a current source, the current value of the sixth current is ensured to be greater than the current value of the fifth current. After the Miller plateau ends, gate discharge is accelerated, allowing the gate voltage to be quickly and completely discharged, shortening the power device shutdown process, and further reducing switching losses.

[0108] In one embodiment, the control method of the power device further includes: a current source configuring the fourth current and / or the fifth current and / or the sixth current in each switching cycle.

[0109] Based on the description in the embodiment of the shutdown control method of the above-mentioned power device, it can be known that in order to ensure the anti-EMI effect and switching loss of the power device in each switching cycle, the current source can configure part or all of the fourth current, fifth current and sixth current corresponding to each switching cycle of the power device.

[0110] Since the shutdown process is the reverse process of the conduction process of the power device, in the shutdown control of the power device, the properties and changes of the driving currents output by the current source can refer to the description in the above-mentioned embodiment of the power device conduction control method. The fourth current can refer to the interpretation of the first current, except that the two have different polarities. The fifth current can refer to the interpretation of the above-mentioned second current, and the two have different polarities. The sixth current can refer to the interpretation of the third current, which will not be repeated here.

[0111] In one embodiment, the third threshold voltage is greater than the first threshold voltage.

[0112] In one embodiment, the fourth threshold is less than the second threshold.

[0113] In one embodiment, the second threshold voltage is equal to the third threshold voltage.

[0114] In one embodiment, the first threshold voltage is equal to the fourth threshold voltage. In this case, the output current switching control during the on / off process relies on fewer threshold voltages, requires simpler hardware circuitry, and requires less computational data. If implemented using a voltage comparator, fewer reference voltages can be set to achieve current source output current switching. This results in lower hardware circuit costs and higher control efficiency.

[0115] In one embodiment, the first current and the fourth current are currents of opposite polarities and equal magnitudes.

[0116] In one embodiment, the second current and the fifth current are currents of opposite polarities and equal magnitudes.

[0117] In one embodiment, the third current and the sixth current are currents of opposite polarities and equal magnitudes.

[0118] By adopting this symmetrical setting method of driving the current in the on-off process, the current source is easier to implement and has a simple structure, which can further reduce costs.

[0119] In the above embodiment, the currents in different stages satisfy the magnitude relationship of the above-mentioned current effective values ​​and do not cause electromagnetic interference. The driving current output by the current source can be a constant current or a current that varies with time. Both settings fall within the protection scope of this application.

[0120] The present application also provides a method for controlling a power device, which is applied to a current source to control the on and off of the power device. The method includes the above-mentioned method for controlling a power device (such as Figure 4 、 7 Steps) and a control method for a power device applied to a current source to control a power device to turn off (such as Figure 9-10 in the steps above).

[0121] The power device control method provided in the embodiments of the present application employs the aforementioned control method of outputting drive currents of varying properties in a segmented manner during both the turn-on and turn-off processes of the power device. This method suppresses electromagnetic interference during the drain-source voltage rise and fall process and accelerates the gate voltage charge and discharge process, thereby significantly shortening the power device's switching cycle and, in other words, reducing switching losses. The specific implementation process can be found in the description of the aforementioned method embodiments and is not detailed here.

[0122] In addition, the control method of the power device provided in the embodiment of the present application does not require additional hardware devices such as dv / dt or di / dt detection circuits. In the application, the first threshold voltage and the third threshold voltage can be configured according to the typical gate characteristics and switching voltage waveform of the specific power device used, as well as the charging / discharging current source under each segment during the on / off process, and the corresponding current is output to drive the gate to charge and discharge in the corresponding time period. As described in the above embodiment, different segments can be distinguished by a simple voltage comparator. Subsequently, the charging / discharging current source under each segment is enabled, and the corresponding current is output to drive the gate to charge and discharge.

[0123] On the other hand, the subject that executes the above control method can rely on a timer to replace the voltage comparator of the above distance to realize segmented control, so that each different segment is controlled by the charge and discharge time configured for the timer (that is, the PWM waveform configured for output). Figure 8 The charging process is divided into three segments: the first segment is set to the time period t0-t2, the second segment is set to the time period t2-t3 (the third segment), and the third segment is not set to a time period until the gate voltage of the power device meets the set drive voltage requirement. Therefore, this drive control method has a low overall implementation cost and is not limited by the hardware circuit framework, with strong adaptability and flexibility.

[0124] The embodiment of the present application proposes a segmented (such as Figure 5 、 Figure 6 The 2-stage type shown, such as Figure 8 The three-stage gate charge and discharge drive control method shown in the figure uses different current sources for optimized control at different stages of gate charge and discharge, which not only controls the drain-source voltage change rate dv / dt and solves the EMI problem; at the same time, it effectively shortens the switching period and reduces switching losses.

[0125] It should be understood that although Figure 4 、 7The steps in the flowcharts of , 9, and 10 are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 4 、 7 At least part of the steps in , 9, and 10 may include multiple steps or multiple stages. These steps or stages do not necessarily have to be performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily one by one, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0126] In one embodiment, Figure 11 As shown, a control device for a power device is provided, which is applied to a current source to control the conduction of the power device, including: a pre-charging module 200 and a first interference suppression module 400, wherein:

[0127] The pre-charging module 200 is configured to instruct the current source to output a first current to pre-charge the gate of the power device so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device;

[0128] a first interference suppression module 400, configured to, after the gate voltage of the power device reaches a first threshold voltage, instruct the current source to output a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device;

[0129] The effective value of the first current is greater than the effective value of the second current.

[0130] In one embodiment, the current source used by the control device of the power device is a constant current source, and the current value of the first current output by the pre-charging module 200 is greater than the current value of the second current output by the first interference suppression module.

[0131] In one embodiment, the control device for a power device used for controlling the conduction of a power device by a current source, the first interference suppression module 400 includes:

[0132] The drain-source voltage drop change rate suppression unit 420 is configured to instruct the current source to output a second current to charge the gate of the power device from the time when the gate voltage of the power device reaches the first threshold voltage to the end of the Miller platform;

[0133] The accelerated charging unit 440 is configured to, after the Miller platform ends, cause the current source to output a third current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement;

[0134] The effective value of the third current is greater than the effective value of the second current.

[0135] In one embodiment, the current source used by the control device of the power device is a constant current source, and the current value of the third current output by the current source indicated by the accelerated charging unit 440 is greater than the current value of the second current output by the drain-source voltage drop change rate suppression unit.

[0136] In one embodiment, Figure 12 As shown, a control device for a power device is provided, which is applied to a current source to control the shutdown of the power device, including: an accelerated discharge module 600 and a second interference suppression module 800, wherein:

[0137] The accelerated discharge module 600 is configured to instruct the current source to output a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device;

[0138] a second interference suppression module 800, configured to, after the gate voltage of the power device drops to a third threshold voltage, instruct the current source to output a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device;

[0139] The effective current value of the fourth current is greater than the effective current value of the fifth current.

[0140] In one embodiment, the current source used by the control device of the power device is a constant current source, and the current value of the fourth current output by the accelerated discharge module 600 is greater than the current value of the fifth current output by the second interference suppression module.

[0141] In one embodiment, the second interference suppression module 800 includes:

[0142] a drain-source voltage rising rate suppression unit 820 , configured to instruct the current source to output a fifth current to discharge the gate of the power device from the time when the gate voltage of the power device drops to the third threshold voltage to the end of the Miller platform;

[0143] The fast discharge unit 840 is used to instruct the current source to output a sixth current to discharge the gate of the power device after the Miller platform ends, until the gate voltage of the power device is completely discharged;

[0144] The effective current value of the sixth current is greater than the effective current value of the fifth current.

[0145] In one embodiment, the current source used by the control device of the power device is a constant current source, and the current value of the sixth current output by the fast discharge unit 840 is greater than the current value of the fifth current output by the drain-source voltage rise rate suppression unit.

[0146] In one embodiment, a control device for a power device is provided, which is applied to a current source to control the on / off of the power device. The device includes: Figure 11 The units and modules in the control device for power devices used for current source control of power device conduction and Figure 12 The units and modules shown are used in a control device for a power device in which a current source is used to control the shutdown of the power device.

[0147] For the specific definition of the control device of the power device, please refer to the definition of the control method of the power device above, which will not be repeated here. The various modules in the control device of the power device can be implemented in whole or in part by software, hardware and their combination. The above modules can be embedded in or independent of the processor in the current source in hardware form, or can be stored in the memory in the current source in software form, so that the processor can call and execute the corresponding operations of the above modules. The specific implementation process of the control device of the power device can also refer to the embodiment description in the steps of the control method of the corresponding power device, which will not be repeated here.

[0148] The present application also provides a current source, the output end of the current source is used to connect to the gate of the power device, and the current source is used to execute the steps of the above-mentioned control method for the power device applied to control the power device to be turned on, and / or, the steps of the above-mentioned control method for the power device applied to control the power device to be turned off.

[0149] In one embodiment, the current source includes a control module and an output module, the control module is electrically connected to the output module, and the output module is used to inject current into the gate of the power device; the control module includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it implements the steps of the power device control method applied to control the power device to be turned on, and / or, the steps of the power device control method applied to control the power device to be turned off.

[0150] In one embodiment, a current source is provided, which may include a control module 920 and an output module 940. The control module 920 includes a processor with a control function such as a microprocessor or a single-chip microcomputer, and the processor is used to control the output current of the output module 940. The internal structure of the current source can be shown as follows: Figure 13As shown. The current source includes a processor, a memory and a current output interface connected by wiring. The processor of the current source can provide data configuration and control capabilities. The memory of the current source includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the current source is used to store the first threshold voltage, the second threshold voltage, the third threshold voltage and the fourth threshold voltage, the time when the gate voltage reaches the first threshold voltage (first segment time), the time when the gate voltage rises from the first threshold voltage to the second threshold voltage (third segment time), the time when the gate voltage drops to the third threshold voltage (second segment time), the time when the gate voltage continues to drop from the third threshold voltage to the fourth threshold voltage (fourth segment time) and the configuration parameters of the first current, the second current, the third current, the fourth current, the fifth current and the sixth current in each switching cycle, etc., to provide a data basis for the current source to perform output current switching control. When the computer program is executed by the processor, the steps of the above-mentioned power device control method are implemented to achieve on-control, off-control, and on-off control of the power device during the entire switching cycle.

[0151] Those skilled in the art will understand that Figure 13 The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present application, and does not constitute a limitation on the current source to which the scheme of the present application is applied. The specific current source may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0152] In one embodiment, when the processor executes the computer program, the steps of the method for controlling the conduction of a power device by a current source are implemented:

[0153] S200: The current source outputs a first current to pre-charge the gate of the power device, so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device;

[0154] S400: After the gate voltage of the power device reaches a first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device;

[0155] The effective value of the first current is greater than the effective value of the second current.

[0156] In one embodiment, when the processor executes the computer program, the steps of the method for controlling the shutdown of a power device by a current source are implemented:

[0157] S600: the current source outputs a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device;

[0158] S800: After the gate voltage of the power device drops to a third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device;

[0159] The effective current value of the fourth current is greater than the effective current value of the fifth current.

[0160] In one embodiment, when the processor executes the computer program, the steps of the method for controlling the turning on and off of a power device by a current source are implemented:

[0161] S200: The current source outputs a first current to pre-charge the gate of the power device, so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device;

[0162] S400: After the gate voltage of the power device reaches a first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device;

[0163] S600: the current source outputs a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device;

[0164] S800: After the gate voltage of the power device drops to a third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device;

[0165] The effective value of the first current is greater than the effective value of the second current; and the effective value of the fourth current is greater than the effective value of the fifth current.

[0166] It should be noted that the current source provided in the embodiments of the present application, when its processor executes a computer program stored in a memory, can be implemented according to the specific description in the above method embodiment and achieve the beneficial effects described in the above method embodiment. For the implementation of other method steps that can be implemented by the current source, reference can be made to the description in the above method embodiment and will not be repeated here.

[0167] Any current source that can output currents of various current values ​​falls within the scope of protection of the driving circuit of this application.

[0168] In one embodiment, the control module can be implemented using a hardware circuit or a logic device. For example, the main body of the control module that implements the output module drive current switching control can use a timer. The timer is used to control the conduction of the power device. The timer is configured as follows:

[0169] Outputting a first electrical signal in a first segment time, the first electrical signal being used to drive the output module to output a first current to pre-charge the gate of the power device, the first segment time being a time period in which the gate voltage of the power device reaches a first threshold voltage;

[0170] After the first segment time, a second electrical signal is output, where the second electrical signal is used to drive the output module to output a second current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement;

[0171] and / or,

[0172] The timer is used to control the shutdown of the power device. The timer is configured as follows:

[0173] Outputting a third electrical signal in a second segment time, the third electrical signal is used to drive the output module to output a fourth current to discharge the gate of the power device, the second segment time being a time period during which the gate voltage of the power device drops to a third threshold voltage;

[0174] After the second segment time, a fourth electrical signal is output, and the fourth electrical signal is used to drive the output module to output a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged.

[0175] By analyzing the typical gate characteristics and switching voltage waveform of a selected power device, the first segmented time for the power device to reach the first threshold voltage and the second segmented time during the shutdown process, when the gate voltage drops from the set drive voltage to the third threshold voltage, are determined. The timer is then directly configured to output different currents to the gate by configuring the waveform of the PWM wave it outputs, namely adjusting the high and low levels at the corresponding segmented times. The timer can be a multi-output timer, with each output corresponding to driving a transistor switch in the output module on or off, thereby opening or closing the current path through the transistor to the gate.

[0176] In one embodiment, the timer is further configured to:

[0177] The second electrical signal is output during the third segment time, and the third segment time is the time period from when the gate voltage of the power device reaches the first threshold voltage to when the Miller platform ends (e.g. Figure 8 The time period t2 to t3 shown);

[0178] After the third segment time, a fifth electrical signal is output, and the fifth electrical signal is used to drive the output module to output a third current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement (such as Figure 8 The t3 to t4 time period).

[0179] In one embodiment, the timer is further configured to:

[0180] outputting a fourth electrical signal during a fourth segmented time, wherein the fourth segmented time is a time period from when the gate voltage of the power device drops to the third threshold voltage to when the Miller platform ends;

[0181] After the fourth segment time, a sixth electrical signal is output, where the sixth electrical signal is used to drive the output module to output a sixth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged.

[0182] Among them, the magnitude relationship and interpretation of the first current, the second current, the third current, the fourth current, the fifth current and the sixth current can all be referred to the description in the above control method embodiment, and will not be repeated here.

[0183] The current source provided in the embodiment of the present application can be configured to have a first segment time of T1 (when the first threshold voltage is equal to the Miller platform voltage, T1 is T2) based on the typical gate characteristics of the power device and the switching voltage waveform. Figure 8 Similarly, it is known that the gate voltage of the power device needs time T3 from the first threshold voltage to the end of the Miller platform, so the third segment time is configured as T3 (for example Figure 8 During the third segment, T3, the current source outputs the second current to suppress the rate of change of the drain-source voltage and avoid electromagnetic interference. After the Miller plateau ends, in the fourth segment, the current source continues to output the third current until the gate voltage of the power device meets the set drive voltage requirement, accelerating the power device conduction process. Therefore, this control method has a low overall implementation cost and is not limited by the hardware circuit framework, making it highly adaptable and flexible.

[0184] Similarly, for the shutdown process, the time period T2 when the gate voltage of the power device drops to the third threshold voltage and the time period T4 from the moment the gate voltage of the power device drops to the third threshold voltage to the end of the Miller platform can be obtained according to the typical gate characteristics of the power device and the switching voltage waveform. The timer is configured with a second segment time T2 and a fourth segment time T4. The timer outputs a third electrical signal in the second segment time T2 to drive the output module to output a larger fourth current to accelerate the gate discharge process of the power device, and then outputs a fourth electrical signal in the fourth segment time T4 to drive the output module to output a fifth current smaller than the fourth current value to perform discharge drive, suppress the drain-source voltage change rate, and prevent electromagnetic interference. After the fourth segment time, the timer outputs a sixth signal to drive the output module to use a sixth current larger than the fifth current value to accelerate gate discharge, shorten the switching cycle, and reduce losses.

[0185] Of course, in addition to the timer exemplified here, the control module can also be implemented using a voltage comparator, and the control module is not limited to being implemented using only a timer or a voltage comparator, but can also include a timer and a voltage comparator or other circuits.

[0186] In one embodiment, Figure 14 As shown, the current source is a transistor saturation current source. The output module of this current source includes multiple pairs of controlled transistors, each connected in series between the operating power supply Vdd and ground. The connection point between each pair of transistors is used to connect to the gate of the power device. When the on-off state of each pair of transistors in the current source changes, the current Isource output to the gate changes accordingly. This change can be achieved by a control device set internal to the current source or by a control device external to the current source. This control device is connected to the gate of each transistor to drive the on-off state of each transistor, thereby changing the drive current output by the current source.

[0187] like Figure 14 The structure shown in FIG. 1 is used as an example of the control method for controlling the conduction of a power device using a current source. Figure 8 In the second stage shown, transistor Q2 is turned on and other transistors are turned off. The drain-source current I2 of transistor Q2 is injected into the gate G of the power device along the connection line to avoid electromagnetic interference in the second stage. Figure 8 In the illustrated stage III, transistor Q1 can also be turned on, causing current I1 to flow through Q1. Therefore, the current output by the current source to the power device gate G is I1 + I2, increasing the current output to the gate and accelerating the rapid charging of the gate voltage to the supply voltage level (i.e., the preset drive voltage requirement). Similarly, for a three-stage control implementation, the same method can be used to change the transistor turned on in the current source, thereby changing the drive current output by the current source.

[0188] In addition, during the implementation of the power device shutdown control method, the current source can change the conduction state of the transistor connected to the ground, thereby providing a negative polarity drive current to drive the gate to discharge.

[0189] In one embodiment, Figure 15 As shown, the current source can be a composite current source including multiple constant current sources. The output module of the current source can include multiple constant current sources, each of which includes two constant current sources. Each current source is connected in series between the working power supply Vdd and the ground. A controlled switch is provided between the constant current source close to the working power supply and the working power supply, and a controlled switch is also provided between the constant current source provided close to the ground and the ground. The change of the on-off state of the controlled switch in the current source (which can be achieved by a control module built into or external to the current source) can affect the current magnitude and polarity ultimately output by the current source to the gate of the power device. The current magnitude provided by each constant current source may be different. By selecting the constant current source inside it and making it work, the current source can achieve current switching output to the gate and execute the steps of the above-mentioned power device control method.

[0190] Similar to the description of the current source embodiment above, a peripheral control module can be used to change the state of each controlled switch within the current source to change the magnitude and polarity of the current output by the current source, thereby executing the steps of the power device control method described above. Alternatively, a control module can be provided within the current source to implement switching control of the output current.

[0191] Of course, the current source can change the output current by controlling one or more controlled switches to be turned on at the same time, which will not be elaborated here.

[0192] In one embodiment, Figure 16 As shown, the current source can be a voltage-controlled current source. In this current source, Ig is fed back through the sampling resistor Rs, and a precise driving current Ig is obtained by changing the driving voltage of the PMOS transistor Qp (i.e., the potential of the pin ON).

[0193] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0194] S200: The current source outputs a first current to pre-charge the gate of the power device, so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device;

[0195] S400: After the gate voltage of the power device reaches a first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device;

[0196] The effective value of the first current is greater than the effective value of the second current.

[0197] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0198] S600: the current source outputs a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device;

[0199] S800: After the gate voltage of the power device drops to a third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device;

[0200] The effective current value of the fourth current is greater than the effective current value of the fifth current.

[0201] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0202] S200: The current source outputs a first current to pre-charge the gate of the power device, so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device;

[0203] S400: After the gate voltage of the power device reaches a first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device;

[0204] S600: the current source outputs a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device;

[0205] S800: After the gate voltage of the power device drops to a third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device;

[0206] The effective value of the first current is greater than the effective value of the second current; and the effective value of the fourth current is greater than the effective value of the fifth current.

[0207] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0208] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0209] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for controlling a power device, characterized in that: The invention is applied to a current source to control the conduction of a power device, wherein the current source is a voltage-controlled current source, the ON pin of the current source is connected to the gate of a PMOS tube, the source of the PMOS tube is connected to the VCC pin of the current source through a sampling resistor Rs, the drain of the PMOS tube is connected to the GATE pin of the current source, and the GATE pin of the current source is connected to a power device; the current Ig provided by the current source to the power device is fed back through the sampling resistor Rs and adjusted by the driving voltage of the PMOS tube; the method comprises: The current source outputs a first current to precharge the gate of the power device so that the gate voltage of the power device reaches a first threshold voltage; the first threshold voltage is less than or equal to the Miller platform voltage of the power device; After the gate voltage of the power device reaches the first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement, wherein the second current is a current that does not cause electromagnetic interference to the power device; The effective value of the first current is greater than the effective value of the second current.

2. The method according to claim 1, characterized in that The current source is a constant current source, and the first current is greater than the second current.

3. The method according to claim 1 or 2, characterized in that The step of "after the gate voltage of the power device reaches the first threshold voltage, the current source outputs a second current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement" includes: From the time when the gate voltage of the power device reaches the first threshold voltage to the end of the Miller platform, the current source outputs the second current to charge the gate of the power device; After the Miller platform ends, the current source outputs a third current to charge the gate of the power device until the gate voltage of the power device meets a set driving voltage requirement; The effective value of the third current is greater than the effective value of the second current.

4. The method according to claim 3, characterized in that The steps of determining the end of the Miller platform include: If the gate voltage of the power device reaches a second threshold voltage, it is determined that the Miller plateau ends, and the second threshold voltage is greater than the first threshold voltage.

5. The method according to claim 3, characterized in that The current source is a constant current source, and the third current is greater than the second current.

6. The method according to claim 5, characterized in that The method further comprises: The current source configures the first current and / or the second current and / or the third current in each switching cycle.

7. A method for controlling a power device, characterized in that: The invention is applied to a current source to control the shutdown of a power device, wherein the current source is a voltage-controlled current source, the ON pin of the current source is connected to the gate of a PMOS transistor, the source of the PMOS transistor is connected to the VCC pin of the current source through a sampling resistor Rs, the drain of the PMOS transistor is connected to the GATE pin of the current source, and the GATE pin of the current source is connected to a power device; the current Ig provided by the current source to the power device is fed back through the sampling resistor Rs and adjusted by the driving voltage of the PMOS transistor; the method comprises: The current source outputs a fourth current to discharge the gate of the power device, so that the gate voltage of the power device drops to a third threshold voltage; the third threshold voltage is greater than or equal to the Miller platform voltage of the power device; After the gate voltage of the power device drops to the third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged, wherein the fifth current is a current that does not cause electromagnetic interference to the power device; The effective current value of the fourth current is greater than the effective current value of the fifth current.

8. The method according to claim 7, characterized in that The current source is a constant current source, and the fourth current is greater than the fifth current.

9. The method according to claim 7 or 8, characterized in that The step of "after the gate voltage of the power device drops to the third threshold voltage, the current source outputs a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged" includes: From the time when the gate voltage of the power device drops to the third threshold voltage until the Miller platform ends, the current source outputs a fifth current to discharge the gate of the power device; After the Miller platform ends, the current source outputs a sixth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged; The effective current value of the sixth current is greater than the effective current value of the fifth current.

10. The method according to claim 9, characterized in that The steps of determining the end of the Miller platform include: If the gate voltage of the power device drops to a fourth threshold voltage, it is determined that the Miller plateau ends, and the fourth threshold voltage is less than the third threshold voltage.

11. The method according to claim 9, characterized in that The current source is a constant current source, and the sixth current is greater than the fifth current.

12. The method according to claim 11, characterized in that The method further comprises: The current source configures the fourth current and / or the fifth current and / or the sixth current in each switching cycle.

13. A method for controlling a power device, characterized in that: The method is applied to controlling the on and off of a power device by a current source, and includes the power device control method according to any one of claims 1 to 6 and the power device control method according to any one of claims 7 to 12.

14. A current source, characterized in that: The output end of the current source is used to connect to the gate of the power device, and the current source is used to perform the steps of the power device control method described in any one of claims 1-6, and / or the steps of the power device control method described in any one of claims 7-12.

15. The current source according to claim 14, characterized in that The current source includes a control module and an output module, the control module is electrically connected to the output module, and the output module is used to inject current into the gate of the power device; The control module includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the steps of the power device control method described in any one of claims 1 to 6 and / or the steps of the power device control method described in any one of claims 7 to 12 are implemented.

16. The current source according to claim 14, wherein: The current source includes a control module and an output module, the control module is electrically connected to the output module, and the output module is used to inject current into the gate of the power device; The control module includes a timer, which is used to control the conduction of the power device. The timer is configured to: Outputting a first electrical signal in a first segment time, wherein the first electrical signal is used to drive the output module to output a first current to pre-charge the gate of the power device, and the first segment time is a time period in which the gate voltage of the power device reaches a first threshold voltage; After the first segmented time has elapsed, a second electrical signal is output, wherein the second electrical signal is used to drive the output module to output a second current to charge the gate of the power device until the gate voltage of the power device meets the set driving voltage requirement; and / or, The timer is used to control the power device to turn off, and the timer is configured as follows: outputting a third electrical signal in a second segment time, wherein the third electrical signal is used to drive the output module to output a fourth current to discharge the gate of the power device, and the second segment time is a time period in which the gate voltage of the power device drops to a third threshold voltage; After the second segment time, a fourth electrical signal is output, where the fourth electrical signal is used to drive the output module to output a fifth current to discharge the gate of the power device until the gate voltage of the power device is completely discharged.

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