Power module and Miller current suppression method

Abstract

The invention provides a power module and a Miller current suppression method. The power module comprises a control circuit and at least one power device. The output end of the control circuit is connected with the grid electrode of each power device in the at least one power device, and the input end of the control circuit is connected with the drain electrode and the grid electrode of each power device in the at least one power device; the control circuit is used for outputting one path of compensation current to the grid electrode of each power device in the at least one power device; wherein the phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the difference between the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device is within a preset range. Therefore, each path of compensation current can offset the Miller current of the corresponding power device, thereby suppressing the Miller effect and eliminating the adverse effect of the Miller current on the switching characteristic of the power device.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a power module and a Miller current suppression method. Background Art

[0002] At present, a large number of power devices are configured in power modules such as automotive modules and industrial modules. Due to their semiconductor structure characteristics, power devices have parasitic junction capacitance inside.

[0003] Parasitic junction capacitance is generally divided into input capacitance, output capacitance and Miller capacitance. Among them, Miller capacitance has a great influence on the switching characteristics of power devices. For example, when the input or output voltage of the power device changes rapidly, the existence of Miller capacitance will lead to Miller effect, which in turn will cause serious switching losses, resulting in energy waste and efficiency loss, and reducing the product's current capacity.

[0004] In addition, power devices are often used in series or in parallel, and crosstalk occurs between devices due to Miller capacitance. The faster the switching speed, the more serious the crosstalk. The Miller effect can easily cause device failure to turn on or off, reducing product reliability. When the power device is turned off at high current, the Miller effect can also cause voltage spikes, which may exceed the device specifications and are not conducive to product safety.

[0005] Therefore, how to suppress the Miller effect of power devices in power modules is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The embodiments of the present application provide a power module and a Miller current suppression method for suppressing the Miller effect in a power device.

[0007] In a first aspect, an embodiment of the present application provides a power module.

[0008] The power module includes a control circuit and at least one power device;

[0009] The output end of the control circuit is connected to the gate of each power device in the at least one power device, and the input end of the control circuit is connected to the drain and gate of each power device in the at least one power device;

[0010] The control circuit is used to output a compensation current to the gate of each power device in at least one power device;

[0011] It should be noted that the phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the difference between the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device is within a preset range.

[0012] Based on the technical solution, the control circuit can output a compensation current to each power device in at least one power device to perform negative feedback regulation on the corresponding power device. Since the compensation current is similar in amplitude to the Miller current in the corresponding power device and has an opposite phase, the compensation current can offset the Miller current, thereby achieving the effect of suppressing the Miller effect and eliminating the adverse effects of the Miller capacitor on the switching characteristics of the power device.

[0013] In a possible design, the amplitude of the compensation current is calculated by the control circuit according to the Miller capacitance value and the drain-gate voltage of the corresponding power device.

[0014] It can be understood that according to the capacitor element current calculation formula, the amplitude of the Miller current should be calculated based on the Miller capacitance value of the power device and the drain-gate voltage of the power device. In addition, the amplitude of the compensation current should be equal to or approximately equal to the amplitude of the Miller current to achieve the suppression effect. Therefore, it is necessary to calculate the amplitude of the compensation current based on the Miller capacitance value and the drain-gate voltage of the power device.

[0015] In a possible design, the amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

[0016] It should be noted that, according to the capacitor element current calculation formula, Ires=|Cres|*(dVDG / dt) can be determined, where Ires is the amplitude of the Miller current, |Cres| is the capacitance of the Miller capacitor, and dVDG / dt is the differential of the drain-gate voltage;

[0017] In addition, the amplitude of the compensation current should be equal to or approximately equal to the amplitude of the Miller current to achieve the suppression effect;

[0018] Therefore, the amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

[0019] In a possible design, the Miller capacitance value is a pre-measured capacitance value of the corresponding power device when the drain-source voltage is zero.

[0020] It can be understood that according to the capacitance-voltage characteristic curve of the capacitor element, the capacitance of the capacitor is affected by the voltage applied to the positive and negative electrodes of the capacitor. The smaller the applied voltage, the larger the capacitance of the capacitor.

[0021] In addition, when the power device is turned on, the potential difference between the source and the drain is very small, generally only a few hundred millivolts or a few volts of voltage drop. Therefore, when the power device is turned on, the Miller capacitance value is close to the capacitance value when the drain-source voltage is zero. Furthermore, when the drain-source voltage is zero, the Miller capacitance value is the largest, which can cover more operating conditions and avoid the problem of insufficient compensation.

[0022] In a possible design, the control circuit includes a sampling circuit, a differential circuit and a differential circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential circuit, and the output end of the differential circuit constitutes the output end of the control circuit;

[0023] A sampling circuit, for sampling a gate and a drain of each power device in at least one power device based on a preset sampling coefficient, and outputting a gate sampling voltage and a drain sampling voltage of each power device in at least one power device;

[0024] A differential circuit, used for performing differential operation on a gate sampling voltage and a drain sampling voltage of each power device in at least one power device, and outputting a drain-gate voltage of each power device in at least one power device;

[0025] A differential circuit, used for performing a differential operation on the drain-gate voltage of each power device in the at least one power device based on a differential coefficient, and outputting a compensation current to the gate of each power device in the at least one power device respectively;

[0026] It should be noted that the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current.

[0027] Based on the technical solution of this design, the gate voltage and drain voltage of the power device are first sampled through the sampling circuit; further, the differential circuit performs differential operation on the gate sampling voltage and the drain sampling voltage, outputs the drain-gate voltage, and the differential circuit performs differential operation on the drain-gate voltage of each power device in at least one power device to obtain the differential amount of the drain-gate voltage, and finally outputs the compensation current to the gate of the corresponding power device. Since the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value, the compensation current amplitude output by the differential circuit is equal to the product of the rate of change of the drain-gate voltage and the Miller capacitance value, that is, the compensation current amplitude is equal to or approximately equal to the Miller current amplitude, and because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current output by the differential circuit can be used to offset the current generated by the Miller capacitance.

[0028] In one possible design, the control circuit includes a sampling circuit, a differential circuit and a differential-multiplication circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential-multiplication circuit, and the output end of the differential-multiplication circuit constitutes the output end of the control circuit;

[0029] A sampling circuit, for sampling a gate and a drain of each power device in at least one power device based on a preset sampling coefficient, and outputting a gate sampling voltage and a drain sampling voltage of each power device in at least one power device;

[0030] A differential circuit, used for performing differential operation on a gate sampling voltage and a drain sampling voltage of each power device in at least one power device, and outputting a drain-gate voltage of each power device in at least one power device;

[0031] A differential-multiplication circuit, used for performing differential operation and signal amplification on the drain-gate voltage of each power device in at least one power device based on a preset differential coefficient and a preset amplification coefficient, and outputting a compensation current to the gate of each power device in at least one power device respectively;

[0032] It should be noted that the product of the sampling coefficient, the differential coefficient and the amplification coefficient of the sampling circuit is equal to the Miller capacitance value corresponding to the compensation current.

[0033] Based on the technical solution of the present design, the sampling circuit first samples the gate voltage and the drain voltage of the power device; further, the differential circuit performs a differential operation on the gate sampling voltage and the drain sampling voltage, and outputs the drain-gate voltage of each power device in at least one power device; the differential-multiplication circuit performs a differential operation on the drain-gate voltage of each power device in at least one power device, and amplifies the input signal in the same direction, and finally outputs a compensation current.

[0034] Since the product of the sampling coefficient, the differential coefficient and the amplification coefficient is equal to the Miller capacitance value, the compensation current amplitude output by the differential-multiplication circuit is equal to the product of the differential of the drain-gate voltage and the Miller capacitance value, that is, the compensation current amplitude is equal to or approximately equal to the Miller current amplitude. Because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current can be used to offset the current generated by the Miller capacitance.

[0035] In a possible design, the input terminal of the control circuit is also connected to the source of each power device in the at least one power device.

[0036] It can be understood that since the capacitance of the capacitor is affected by the drain-source voltage of the power device, the control circuit can sample the source voltage of the power device, and further calculate the source-drain voltage in combination with the sampled drain voltage, thereby determining the capacitance of the Miller capacitor.

[0037] In a possible design, the Miller capacitance value is obtained by the control circuit based on the drain-source voltage of the corresponding power device and a preset Miller capacitance value-drain-source voltage curve.

[0038] It is understandable that since the capacitance of the Miller capacitor will change according to the voltage applied to the drain and source of the power device, the Miller capacitance value-drain-source voltage curve is used for feedback compensation, which has a more obvious suppression effect and avoids the risk of over-compensation.

[0039] In a second aspect, an embodiment of the present application provides a Miller current suppression method, which is applied to a power module, wherein the power module includes a control circuit and at least one power device;

[0040] The output end of the control circuit is connected to the gate of each power device in the at least one power device, and the input end of the control circuit is connected to the drain and gate of each power device in the at least one power device;

[0041] The method includes:

[0042] The control circuit outputs a compensation current to the gate of each power device in at least one power device respectively;

[0043] It should be noted that the phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the difference between the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device is within a preset range.

[0044] Based on the technical solution, the control circuit can output a compensation current to each power device in at least one power device to perform negative feedback regulation on the corresponding power device. Since the compensation current is similar in amplitude to the Miller current in the corresponding power device and has an opposite phase, the compensation current can offset the Miller current, thereby achieving the effect of suppressing the Miller effect and eliminating the adverse effects of the Miller capacitor on the switching characteristics of the power device.

[0045] In a possible design, the amplitude of the compensation current is calculated by the control circuit according to the Miller capacitance value and the drain-gate voltage of the corresponding power device.

[0046] It can be understood that according to the capacitor element current calculation formula, the amplitude of the Miller current should be calculated based on the Miller capacitance value of the power device and the drain-gate voltage of the power device. In addition, the amplitude of the compensation current should be equal to or approximately equal to the amplitude of the Miller current to achieve the suppression effect. Therefore, it is necessary to calculate the amplitude of the compensation current based on the Miller capacitance value and the drain-gate voltage of the power device.

[0047] In a possible design, the amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

[0048] It should be noted that, according to the capacitor element current calculation formula, Ires=|Cres|*(dVDG / dt) can be determined, where Ires is the amplitude of the Miller current, |Cres| is the capacitance of the Miller capacitor, and dVDG / dt is the differential of the drain-gate voltage;

[0049] In addition, the amplitude of the compensation current should be equal to or approximately equal to the amplitude of the Miller current to achieve the suppression effect;

[0050] Therefore, the amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

[0051] In a possible design, the Miller capacitance value is a pre-measured capacitance value of the corresponding power device when the drain-source voltage is zero.

[0052] It can be understood that according to the capacitance-voltage characteristic curve of the capacitor element, the capacitance of the capacitor is affected by the voltage applied to the positive and negative electrodes of the capacitor. The smaller the applied voltage, the larger the capacitance of the capacitor.

[0053] In addition, when the power device is turned on, the potential difference between the source and the drain is very small, generally only a few hundred millivolts or a few volts of voltage drop. Therefore, when the power device is turned on, the Miller capacitance value is close to the capacitance value when the drain-source voltage is zero. Furthermore, when the drain-source voltage is zero, the Miller capacitance value is the largest, which can cover more operating conditions and avoid the problem of insufficient compensation.

[0054] In a possible design, the control circuit includes a sampling circuit, a differential circuit and a differential circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential circuit, and the output end of the differential circuit constitutes the output end of the control circuit;

[0055] The control circuit outputs a compensation current to the gate of each power device in at least one power device, including:

[0056] The sampling circuit samples the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and outputs a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device;

[0057] The differential circuit performs differential operation on the gate sampling voltage and the drain sampling voltage of each power device in the at least one power device, and outputs the drain-gate voltage of each power device in the at least one power device;

[0058] The differential circuit performs a differential operation on the drain-gate voltage of each power device in at least one power device based on a differential coefficient, and outputs a compensation current to the gate of each power device in at least one power device respectively; wherein the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current.

[0059] Based on the technical solution of this design, the gate voltage and drain voltage of the power device are first sampled through the sampling circuit; further, the differential circuit performs differential operation on the gate sampling voltage and the drain sampling voltage, outputs the drain-gate voltage, and the differential circuit performs differential operation on the drain-gate voltage of each power device in at least one power device to obtain the rate of change of the drain-gate voltage, and finally outputs the compensation current to the gate of the corresponding power device. Since the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value, the amplitude of the compensation current output by the differential circuit is equal to the product of the rate of change of the drain-gate voltage and the Miller capacitance value, that is, the amplitude of the compensation current is equal to or approximately equal to the amplitude of the Miller current, and because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current output by the differential circuit can be used to offset the current generated by the Miller capacitance.

[0060] In one possible design, the control circuit includes a sampling circuit, a differential circuit and a differential-multiplication circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential-multiplication circuit, and the output end of the differential-multiplication circuit constitutes the output end of the control circuit;

[0061] The control circuit outputs a compensation current to the gate of each power device in at least one power device, including:

[0062] The sampling circuit samples the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and outputs a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device;

[0063] The differential circuit performs differential operation on the gate sampling voltage and the drain sampling voltage of each power device in the at least one power device, and outputs the drain-gate voltage of each power device in the at least one power device;

[0064] The differential-multiplication circuit performs differential operation and signal amplification on the drain-gate voltage of each power device in at least one power device based on a preset differential coefficient and a preset amplification coefficient, and outputs a compensation current to the gate of each power device in at least one power device respectively; wherein the product of the sampling coefficient, the differential coefficient and the amplification coefficient of the sampling circuit is equal to the Miller capacitance value of the power device corresponding to the compensation current.

[0065] Based on the technical solution of the present design, first, the sampling circuit samples the gate voltage and the drain voltage of the power device; further, the differential circuit performs a differential operation on the gate sampling voltage and the drain sampling voltage, and outputs the drain-gate voltage of each power device in at least one power device; the differential-multiplication circuit performs a differential operation on the drain-gate voltage of each power device in at least one power device, obtains the rate of change of the drain-gate voltage, and amplifies the input signal in the same direction, and finally outputs a compensation current.

[0066] Since the product of the sampling coefficient, the differential coefficient and the amplification coefficient is equal to the Miller capacitance value, the compensation current amplitude output by the differential-multiplication circuit is equal to the product of the rate of change of the drain-gate voltage and the Miller capacitance value, that is, the compensation current amplitude is equal to or approximately equal to the Miller current amplitude. Because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current can be used to offset the current generated by the Miller capacitance.

[0067] In one possible design, the input end of the control circuit is also connected to the source of each power device in at least one power device, and the Miller capacitance value is obtained by the control circuit based on the drain-source voltage of the corresponding power device and a preset Miller capacitance value-drain-source voltage curve.

[0068] It can be understood that since the capacitance of the capacitor is affected by the drain-source voltage of the power device, the control circuit can sample the source voltage of the power device, and further calculate the source-drain voltage in combination with the sampled drain voltage, thereby determining the capacitance of the Miller capacitor.

[0069] Based on the technical solution of this design, since the capacitance of the Miller capacitor will change according to the voltage applied to the drain and source of the power device, the Miller capacitance value-drain-source voltage curve is used for feedback compensation, which has a more obvious suppression effect and avoids the risk of over-compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 A schematic diagram of the structure of a power module provided in an embodiment of the present application;

[0071] Figure 2 A schematic diagram of a Miller capacitance-drain-source voltage curve provided in an embodiment of the present application;

[0072] Figure 3a A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0073] Figure 3b A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0074] Figure 3c A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0075] Figure 4a A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0076] Figure 4b A schematic diagram of the structure of another power module provided in an embodiment of the present application;

[0077] Figure 5A schematic diagram of a process of suppressing Miller current provided in an embodiment of the present application;

[0078] Figure 6 A schematic flow chart of another Miller current suppression method provided in an embodiment of the present application;

[0079] Figure 7 A schematic flow chart of another Miller current suppression method provided in an embodiment of the present application;

[0080] Figure 8 A schematic flow chart of another Miller current suppression method provided in an embodiment of the present application;

[0081] Fig. 9 A schematic diagram of an application of a chip provided in an embodiment of the present application. DETAILED DESCRIPTION

[0082] To facilitate understanding of the embodiments of the present application, the following explains the terms involved in the embodiments of the present application:

[0083] 1. Miller Current

[0084] Miller current refers to the current generated on the Miller capacitor during the switching transition of the power device due to the influence of the capacitance characteristics and the inability of the current to immediately follow the voltage change.

[0085] 2. Miller Effect

[0086] Miller effect refers to a feedback effect between the input and output ends of electronic components such as power tubes due to the capacitance between the input signal and the AC path.

[0087] For example, when there is capacitive coupling from input to output in a power device, the signal at the input will pass through the gain stage inside the amplifier and then pass through the capacitor at the output again. Due to the presence of the capacitor, the signal will be fed back to the input, forming a feedback loop, and the effect of this feedback loop on gain and frequency response is the Miller effect.

[0088] In order to make the purpose, technical solutions and advantages of the present application clearer, the following is a clear and complete description of the application scenarios of the technical solutions in the embodiments of the present application and the technical problems to be solved:

[0089] A large number of power devices are generally configured in the power module, and due to their semiconductor structure characteristics, power devices will have internal parasitic junction capacitance. Parasitic junction capacitance is generally divided into input capacitance, output capacitance and Miller capacitance, among which Miller capacitance has the greatest impact on the switching characteristics of power devices. For example, since most power devices are in the switching process of inductive loads, the input or output voltage of the power device will change rapidly, but the charge of the parasitic junction capacitance cannot respond to the change in time, which will cause charge accumulation or discharge. This means that during the switching transition, there is a delay or overlap period between voltage and current, which is called the Miller platform.

[0090] During the Miller platform, due to the existence of Miller capacitance, the current cannot change immediately with the change of voltage, thereby generating Miller current and causing unstable oscillation, that is, the Miller effect. The Miller effect will cause additional switching losses, resulting in energy waste and efficiency loss, and reducing the product's current capacity.

[0091] In addition, due to Miller capacitance, crosstalk is easily formed between the interconnected power devices. The faster the switching speed, the greater the crosstalk, which leads to the Miller effect. The obvious oscillation caused by this Miller effect can easily cause abnormal switching on and off of power devices and voltage spikes, which may exceed the device specifications and reduce product reliability.

[0092] Therefore, how to suppress the Miller effect in power devices is a technical problem that needs to be solved urgently.

[0093] Based on the above problems, the embodiments of the present application provide a power module and a Miller current suppression method to suppress the Miller effect in a power device.

[0094] The power module provided by the exemplary embodiment of the present application is described below in combination with the application scenarios described above and with reference to the accompanying drawings. It should be noted that the above application scenarios are only shown to facilitate understanding of the principles of the present application, and the embodiments of the present application are not limited in this respect.

[0095] Illustratively, the power module of the present application can be applied in photovoltaic scenarios or photovoltaic-storage integrated scenarios, for example, the power module is integrated in a photovoltaic-storage inverter. The power module of the present application can be applied in the field of new energy vehicles, for example, the power module is integrated in a vehicle-mounted motor controller. In addition, the power module can also be applied in data centers, station energy and other fields, which will not be elaborated here.

[0096] Figure 1 A power module is provided for an embodiment of the present application. The power module includes a control circuit 10 and at least one power device ( Figure 1 In the figure, power devices Q1 to Qn are connected in parallel.

[0097] It should be noted that the embodiments of the present application can be applied to power devices of power modules, and can also be applied to other circuits composed of power devices, including but not limited to half-bridge circuits, full-bridge circuits, three-phase full-bridge circuits, I-type three-level circuits, T-type three-level circuits, etc.

[0098] The output terminal A1 of the control circuit 10 is connected to the gate G of each power device in at least one power device, and the input terminal A2 of the control circuit 10 is connected to the drain D and the gate G of each power device in at least one power device (for ease of observation, the connection lines between the control circuit 10 and the drain D and the gate G of each power device in at least one power device are not shown).

[0099] The control circuit 10 is used to output a compensation current to the gate of each power device in at least one power device.

[0100] It should be noted that the phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the difference between the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device is within a preset range;

[0101] In addition, the Miller current is Figure 1 Miller capacitance Cres (Since Miller capacitance Cres is a parasitic capacitance inside the power device, Figure 1 The Miller capacitance Cres in the circuit is not a physical capacitor device).

[0102] Exemplarily, the Miller current phase of the power device is 0°, the phase of the compensation current is 180°, the preset range is 0-1A, and the effective value of the current is measured experimentally to obtain: the Miller current amplitude (effective value) is 1.4A, the compensation current amplitude (effective value) output by the control circuit is 0.7A, and the difference between the compensation current amplitude and the Miller current amplitude is 0.7A;

[0103] It can be seen that the phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device are within a preset range, so the compensation current output by the control circuit can offset the Miller current.

[0104] Exemplarily, when the Miller current phase of the power device is 0°, the phase of the compensation current is 180°, and the preset range is 0-5A. The current peak value is measured experimentally and the Miller current amplitude (peak value) is 16A, the compensation current amplitude (peak value) output by the control circuit is 11.5A, and the difference between the compensation current amplitude and the Miller current amplitude is 4.5A.

[0105] It can be seen that the phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device are within a preset range, so the compensation current output by the control circuit can offset the Miller current.

[0106] The control circuit in the present application can output a compensation current with a similar amplitude and opposite phase to the Miller current. The compensation current can negatively offset the Miller current, thereby achieving the effect of suppressing the Miller effect, eliminating the adverse effects of the Miller capacitor on the switching characteristics of the power device, reducing the voltage oscillation and voltage spikes of the power device, and improving the reliability and safety of the power module.

[0107] The following describes how to calculate the amplitude of the above compensation current in this application in conjunction with an embodiment:

[0108] In a possible embodiment, the amplitude of the compensation current is calculated by the control circuit according to the Miller capacitance value and the drain-gate voltage of the corresponding power device.

[0109] It should be noted that the current of the capacitor element can be calculated by formula 1:

[0110] I=|C|*(du / dt) Formula 1

[0111] Where I represents the capacitance current amplitude, C represents the capacitance value, and du / dt represents the capacitance voltage change rate;

[0112] It can be seen that the amplitude of the Miller current Cres can be calculated based on the Miller capacitance value of the power device and the voltage across the Miller capacitance Cres, and the voltage across the Miller capacitance Cres is the drain-gate voltage of the power device;

[0113] In addition, the amplitude of the compensation current should be equal to or approximately equal to the amplitude of the Miller current Ires to achieve the suppression effect;

[0114] Therefore, the amplitude of the compensation current needs to be calculated based on the Miller capacitance value and the drain-gate voltage of the power device.

[0115] Furthermore, by substituting the working condition of the Miller capacitor Cres into the current calculation formula of the above capacitor element, we can obtain Formula 2:

[0116] Ires=|Cres|*(dVDG / dt) Formula 2

[0117] Among them, Ires represents the amplitude of Miller current, |Cres| represents the Miller capacitance value, and dVDG / dt represents the differential of drain-gate voltage;

[0118] Therefore, in a possible implementation manner, the amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

[0119] The present application can calculate the drain-gate voltage differential dVDG / dt by sampling the voltage of the drain-gate of the power device through the control circuit 10. The following describes how to obtain the Miller capacitance value |Cres| in conjunction with the embodiment, and further describes how the control circuit 10 outputs the compensation current according to the drain-gate voltage differential dVDG / dt and the Miller capacitance value |Cres|:

[0120] Embodiment 1

[0121] The Miller capacitance value |Cres| is a pre-measured capacitance value of the corresponding power device when the drain-source voltage is zero.

[0122] It should be noted that observing Figure 2 From the Miller capacitance value-drain-source voltage curve shown, it can be seen that the capacitance of the Miller capacitor is affected by the voltage applied to the positive and negative electrodes of the Miller capacitor. The smaller the applied voltage, the larger the capacitance of the Miller capacitor.

[0123] In addition, when the power device is turned on, the potential difference between the source and the drain is very small, generally only a few hundred millivolts or a few volts of voltage drop. Therefore, when the power device is turned on, the Miller capacitance value is close to the capacitance value when the drain-source voltage is zero. Furthermore, when the drain-source voltage is zero, the Miller capacitance value is the largest, which can cover more operating conditions and avoid the problem of insufficient compensation.

[0124] In a possible implementation, Figure 3a As shown, the control circuit 10 includes a sampling circuit 301, a differential circuit 302 and a differential circuit 303; wherein the input end of the sampling circuit 301 constitutes the input end A2 of the control circuit 10, the differential circuit 302 is connected between the sampling circuit 301 and the differential circuit 303, and the output end of the differential circuit 303 constitutes the output end A1 of the control circuit 10;

[0125] The sampling circuit 301 is used to sample the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and output a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device;

[0126] A differential circuit 302, configured to perform differential operation on a gate sampling voltage and a drain sampling voltage of each power device in at least one power device, and output a drain-gate voltage of each power device in at least one power device;

[0127] A differential circuit 303, configured to perform a differential operation on the drain-gate voltage of each power device in the at least one power device based on a differential coefficient, and output a compensation current to the gate of each power device in the at least one power device;

[0128] It should be noted that the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value |Cres| of the power device corresponding to the compensation current.

[0129] Based on the technical solution in this embodiment, the gate voltage and the drain voltage of the power device are sampled by the sampling circuit 301; further, the differential circuit 302 performs a differential operation on the gate sampling voltage and the drain sampling voltage to output the drain-gate voltage, and the differential circuit 303 performs a differential operation on the drain-gate voltage of each power device in at least one power device to obtain the differential amount of the drain-gate voltage. In addition, the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current, and finally the compensation current is output to the gate of the corresponding power device respectively.

[0130] Since the amplitude of the compensation current output by the differential circuit 303 is equal to the product of the differential of the drain-gate voltage and the Miller capacitance value, that is, the amplitude of the compensation current is equal to or approximately equal to the amplitude of the Miller current, and because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current output by the differential circuit 303 can be used to offset the current generated by the Miller capacitance.

[0131] Those skilled in the art should know that the control circuit 10 of the present application can be designed using an analog signal operation circuit or a digital logic circuit, so that the circuit design parameters are highly adaptable and can meet the requirements of long-term engineering use. In addition, due to the use of active circuits such as analog signal operation circuits or digital logic circuits, the control circuit 10 can not only eliminate voltage oscillations or spikes, but also ensure that the switching loss of the power device is basically unaffected or even reduces the switching loss, thereby ensuring the current-carrying capacity of the power device while improving product quality.

[0132] For example, Figure 4a As shown, the differential circuit 302 includes a resistor R1, a resistor R2, a feedback resistor R3, a grounding resistor R4 and an integrated amplifier A; the gate voltage m*VG and the drain voltage m*VD collected by the sampling circuit 301 are applied to the inverting input terminal and the non-inverting input terminal of the integrated amplifier A through the resistor R1 and the resistor R2 respectively, and the output terminal of the integrated amplifier A is connected back to the inverting input terminal through the feedback resistor R3;

[0133] In addition, in order to ensure the balance of the resistance between the two input terminals of the operational amplifier and to avoid reducing the common mode rejection ratio, the resistance values ​​of resistors R1 and R2 are set equal in advance, and the resistance values ​​of feedback resistors R3 and grounding resistors 4 are set equal;

[0134] The differential circuit 303 includes a feedback resistor R5, a grounding resistor R6, a differential capacitor Cd and an integrated amplifier B; the drain-gate voltage m*VDG of each power device in at least one power device output by the differential circuit 302 is input into the inverting input terminal of the integrated amplifier B through the differential capacitor Cd, the non-inverting input terminal of the integrated amplifier B is grounded through the grounding resistor R6, and the output terminal of the integrated amplifier B is connected back to the inverting input terminal through the feedback resistor R5.

[0135] Below Figure 4a The working process of the control circuit 10 shown is introduced as follows:

[0136] The sampling circuit 301 proportionally adjusts the gate voltage VG and drain voltage VD of the collected power device by a sampling coefficient m (the sampling coefficient m is generally 0.01), and outputs the gate voltage m*VG of each power device and the drain voltage m*VD of each power device;

[0137] The differential circuit 302 performs a differential operation on m*VG and m*VD, and outputs a drain-gate voltage m*VDG of each power device in at least one power device;

[0138] After the input drain-gate voltage m*VDG of each power device is differentiated by the differential circuit 303, the differential circuit 303 outputs the compensation current I1. The differential processing of the differential circuit 303 can be equivalent to Formula 3:

[0139] I1=-1*m*Cd*R5*(dVDG / dt) Formula 3

[0140] It should be noted that, when the Miller current Ires of the Miller capacitor Cres of the power device is in a positive phase, -1 indicates that the phase of the compensation current I1 is a negative phase, and when the Miller current Ires of the Miller capacitor Cres of the power device is in a negative phase, -1 indicates that the phase of the compensation current I1 is a positive phase; dVDG / dt is the differential of the drain-gate voltage VDG, which indicates the rate of change of the drain-gate voltage VDG;

[0141] To further simplify the calculation process, Cd*R5 can be recorded as the differential coefficient n (the differential coefficient n is generally less than 1), and because the product of the sampling coefficient m and the differential coefficient n is equal to the Miller capacitance value |Cres|, it can be substituted into Formula 3 to obtain: I1 = -1*m*n*(dVDG / dt) = -1*|Cres|*(dVDG / dt);

[0142] Since the Miller current Ires of the Miller capacitor Cres of the power device is |Cres|*(dVDG / dt), it can be deduced that |I1|≈|Ires|, that is, the current value of the compensation current is approximately equal to the current value of the Miller capacitor;

[0143] Since the phase of the compensation current is opposite to that of the Miller current, the compensation current I1 output by the control circuit 10 can be used to offset the Miller current of the corresponding power device, thereby achieving the effect of suppressing the Miller effect.

[0144] In another possible implementation, Figure 3b As shown, the control circuit 10 includes a sampling circuit 301, a differential circuit 302 and a differential-multiplication circuit 304; wherein, the input terminal A2 of the sampling circuit 301 constitutes the input terminal of the control circuit 10, the differential circuit 302 is connected between the sampling circuit 301 and the differential-multiplication circuit 304, and the output terminal of the differential-multiplication circuit 304 constitutes the output terminal A1 of the control circuit 10;

[0145] The control circuit 10 outputs a compensation current to the gate of each power device in at least one power device, including:

[0146] The sampling circuit 301 is used to sample the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and output a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device;

[0147] A differential circuit 302, configured to perform differential operation on a gate sampling voltage and a drain sampling voltage of each power device in at least one power device, and output a drain-gate voltage of each power device in at least one power device;

[0148] A differential-multiplication circuit 304 is used to perform differential operation and signal amplification on the drain-gate voltage of each power device in the at least one power device based on a preset differential coefficient and a preset amplification coefficient, and output a compensation current to the gate of each power device in the at least one power device;

[0149] It should be noted that the product of the sampling coefficient, the differential coefficient and the amplification coefficient of the sampling circuit 301 is equal to the Miller capacitance value of the power device corresponding to the compensation current.

[0150] Based on the technical solution in this embodiment, the sampling circuit 301 first samples the gate voltage and the drain voltage of the power device; further, the differential circuit 302 performs a differential operation on the gate sampling voltage and the drain sampling voltage, and outputs the drain-gate voltage of each power device in at least one power device. The differential-multiplication circuit 304 performs a differential operation on the drain-gate voltage of each power device in at least one power device, and performs a same-direction proportional amplification, and finally outputs a compensation current.

[0151] Since the product of the sampling coefficient, the differential coefficient and the amplification coefficient is equal to the Miller capacitance value |Cres|, the compensation current amplitude output by the differential-multiplication circuit 304 is equal to the product of the differential of the drain-gate voltage and the Miller capacitance value, that is, the compensation current amplitude is equal to or approximately equal to the Miller current amplitude. Because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current can be used to offset the current generated by the Miller capacitance.

[0152] Those skilled in the art should know that the differential circuit 302 and the differential-multiplication circuit 304 can be designed by using an analog signal operation circuit or a digital logic circuit; taking the analog signal operation circuit as an example, the differential-multiplication circuit 304 can include a differential circuit 303 and a multiplication circuit 3041 connected in series, and the present application does not limit the order of the differential circuit 303 and the multiplication circuit 3041 connected in series;

[0153] For example, Figure 4b As shown, the multiplication circuit 3041 includes a grounding resistor R7, a compensation resistor R8, a feedback resistor R9 and an integrated operational amplifier C; wherein the input end of the sampling circuit 301 constitutes the input end A2 of the control circuit 10, the differential circuit 302 is connected between the sampling circuit 301 and the differential-multiplication circuit 304, the differential circuit 303 of the differential-multiplication circuit 304 is connected between the differential circuit 302 and the multiplication circuit 3041, and the output end of the multiplication circuit 3041 constitutes the output end A1 of the control circuit 10;

[0154] The differential current I' output by the differential circuit 303 is applied to the non-inverting input terminal of the integrated amplifier C through the compensation resistor R8, the inverting input terminal of the integrated amplifier C is grounded through the grounding resistor R7, and the output terminal of the integrated amplifier C is connected back to the inverting input terminal through the feedback resistor R9;

[0155] It should be noted that the resistance of the compensation resistor R8 is equal to the ratio of the resistance of the feedback resistor R9 to the resistance of the grounding resistor R7;

[0156] In addition, the structure of the differential circuit 302 and the differential circuit 303 can be referred to above. Figure 4a Description of the circuit structure shown;

[0157] Below Figure 4b The working process of the control circuit 10 shown is introduced as follows:

[0158] The sampling circuit 301 proportionally adjusts the gate voltage VG and drain voltage VD of the collected power device by a sampling coefficient m (the sampling coefficient m is generally 0.01), and outputs a gate sampling voltage m*VG of each power device and a drain sampling voltage m*VD of each power device;

[0159] The drain-gate voltage m*VDG of each power device in at least one power device output by the differential circuit 302;

[0160] After the input drain-gate voltage m*VDG of each power device is differentiated by the differential circuit 303, the differential current I1 output by the differential circuit 303 and the differential amplification process of the differential-multiplication circuit 304 can be equivalent to Formula 4:

[0161] I1=-1*m*Cd*R5*(dVDG / dt)*(1+R9 / R7) Formula 4

[0162] To simplify the calculation process, Cd*R5 can be recorded as the differential coefficient n (the differential coefficient n is generally less than 1), and (1+R9 / R7) can be recorded as the amplification coefficient k (the amplification coefficient k is generally greater than or equal to 1); because the product of the sampling coefficient m, the differential coefficient n and the amplification coefficient k is equal to the Miller capacitance value |Cres|, so substituting it into formula 4 can obtain: I1=-1*m*n*k*(dVDG / dt)=-1*|Cres|*(dVDG / dt);

[0163] Since the Miller current Ires of the Miller capacitor Cres of the power device is |Cres|*(dVDG / dt), it can be deduced that |I1|≈|Ires|, that is, the current value of the compensation current is approximately equal to the current value of the Miller capacitor;

[0164] Since the phase of the compensation current is opposite to that of the Miller current, the compensation current I1 output by the control circuit 10 can be used to offset the Miller current of the corresponding power device, thereby achieving the effect of suppressing the Miller effect.

[0165] Embodiment 2

[0166] like Figure 3c As shown, the input end of the control circuit 10 is also connected to the source S of each power device in at least one power device (for ease of observation, the connection line between the control circuit 10 and the source S of each power device in at least one power device is not shown).

[0167] Understandable, such as Figure 2 As shown, the capacitance of the Miller capacitor is affected by the drain-source voltage of the power device, so the control circuit 10 can sample the source voltage of the power device, and further calculate the source-drain voltage in combination with the sampled drain voltage, thereby determining the Miller capacitance value |Cres|.

[0168] In a possible implementation manner, the Miller capacitance value |Cres| is obtained by the control circuit 10 based on the drain-source voltage of the corresponding power device and a preset Miller capacitance value-drain-source voltage curve;

[0169] Exemplarily, the control circuit 10 samples the drain voltage and the source voltage of each power device in at least one power device, and calculates the drain-source voltage;

[0170] Further, the control circuit 10 identifies the Miller capacitance value corresponding to the drain-source voltage according to a preset Miller capacitance value-drain-source voltage curve;

[0171] Finally, the control circuit 10 calculates the amplitude of the compensation current based on the product of the Miller capacitance value and the differential of the drain-gate voltage, and outputs the compensation current to the gate of the corresponding power device in a phase opposite to the Miller current.

[0172] Based on the technical solution of this embodiment, the control circuit 10 can output a compensation current with a similar amplitude and opposite phase to the Miller current according to the drain-gate voltage differential, the preset Miller capacitance value-drain-source voltage curve and the drain-source voltage. Therefore, the compensation current can offset the Miller current, thereby achieving the effect of suppressing the Miller effect and eliminating the adverse effects of the Miller capacitance on the switching characteristics of the power device.

[0173] In addition, since in actual engineering, the Miller capacitance value will change according to the different voltages applied to the drain and source of the power device, compared with directly using the Miller capacitance value measured when the drain-source voltage is zero to calculate the compensation current value, the compensation current amplitude calculated by the Miller capacitance value-drain-source voltage curve in this embodiment is more accurate and can avoid the risk of over-compensation.

[0174] In summary, the embodiments of the present application provide a variety of control circuits for suppressing the Miller current of power devices, and the main technical concept is: the control circuit calculates the Miller capacitance value by pre-measured Miller capacitance value when the drain-source voltage is zero or based on the drain-source voltage of the power device and a preset Miller capacitance value-drain-source voltage curve; on the other hand, the control circuit calculates the differential of the drain-gate voltage by sampling the drain and gate of the power device, and finally calculates the amplitude of the compensation current according to the Miller capacitance value and the differential of the drain-gate voltage, and outputs the compensation current in combination with the phase opposite to the Miller current;

[0175] In this way, the amplitude of the output compensation current is close to or even equal to the amplitude of the Miller current, and the phase of the compensation current is opposite to the phase of the Miller current, so that the compensation current output by the control circuit can offset the Miller current, thereby suppressing the Miller effect.

[0176] Based on the same technical concept, the present application also provides a Miller current suppression method, which is applied to Figure 1 The control circuit 10 shown, the structure of the control circuit 10 is as described above, and will not be repeated here;

[0177] like Figure 5 As shown, the Miller current suppression method includes:

[0178] Step 501: The control circuit calculates the amplitude of the compensation current.

[0179] Step 502: The control circuit outputs a compensation current to the gate of each power device in at least one power device.

[0180] It should be noted that the phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the difference between the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device is within a preset range.

[0181] Based on the technical solution in this embodiment, the control circuit can output a compensation current to each power device in at least one power device to perform negative feedback regulation on the corresponding power device. Since the compensation current is similar in amplitude to the Miller current in the corresponding power device and has an opposite phase, the compensation current can offset the Miller current, thereby achieving the effect of suppressing the Miller effect, reducing the voltage oscillation and voltage spike of the power device, and improving the reliability and safety of the power module.

[0182] In a possible implementation manner, the amplitude of the compensation current is calculated by the control circuit according to the Miller capacitance value and the drain-gate voltage of the corresponding power device.

[0183] It can be understood that according to Formula 1, the amplitude of the Miller current Cres can be calculated based on the Miller capacitance value of the power device and the voltage across the Miller capacitance Cres, and the voltage across the Miller capacitance Cres is the drain-gate voltage of the power device; in addition, the amplitude of the compensation current should be equal to or approximately equal to the amplitude of the Miller current Ires to achieve the suppression effect;

[0184] Therefore, the amplitude of the compensation current needs to be calculated based on the Miller capacitance value and the drain-gate voltage of the power device.

[0185] Furthermore, the amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

[0186] The Miller current suppression method provided by the present application is described below in conjunction with the embodiments:

[0187] Embodiment 1

[0188] like Figure 6 As shown, the Miller current suppression method is applied to Figure 3a For the power module shown, the Miller current suppression method includes:

[0189] Step 601: The sampling circuit samples the gate and drain of each power device in at least one power device based on a preset sampling coefficient, and outputs a gate sampling voltage and a drain sampling voltage of each power device in at least one power device.

[0190] It should be noted that the sampling coefficient refers to the ratio between the sampling frequency used when sampling a signal and the actual frequency of the signal in signal processing. For example, the sampling coefficient can be 0.01.

[0191] Step 602: The differential circuit performs a differential operation on the gate sampling voltage and the drain sampling voltage of each power device in at least one power device, and outputs the drain-gate voltage of each power device in at least one power device.

[0192] For example, if the gate sampling voltage of each power device in at least one power device collected is 15V and the drain sampling voltage is 100V, the control circuit performs differential calculation on the gate sampling voltage and the drain sampling voltage to obtain a drain-gate voltage of 85V.

[0193] Step 603: The differential circuit performs a differential operation on the drain-gate voltage of each power device in the at least one power device based on the differential coefficient, and outputs a compensation current to the gate of each power device in the at least one power device.

[0194] It should be noted that the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current, wherein the Miller capacitance value is the capacitance value of the corresponding power device measured in advance when the drain-source voltage is zero. In this way, the amplitude of the compensation current calculated by combining the differential value of the drain-gate voltage and formula 2 is close to the amplitude of the Miller current;

[0195] This is because when the power device is turned on, the potential difference between the source and the drain is very small, generally only a few hundred millivolts or a few volts of voltage drop. Therefore, when the power device is turned on, the Miller capacitance value is close to the capacitance value when the drain-source voltage is zero. Furthermore, when the drain-source voltage is zero, the Miller capacitance value is the largest, which can cover more operating conditions and avoid the problem of insufficient compensation.

[0196] Based on the technical solution in this embodiment, the gate voltage and drain voltage of the power device are sampled by a sampling circuit; further, the differential circuit performs a differential operation on the gate sampling voltage and the drain sampling voltage to output the drain-gate voltage, and the differential circuit performs a differential operation on the drain-gate voltage of each power device in at least one power device to obtain the differential amount of the drain-gate voltage. In addition, the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current, and finally the compensation current is output to the gates of the corresponding power devices respectively.

[0197] Since the compensation current amplitude output by the differential circuit is equal to the product of the differential amount of the drain-gate voltage and the Miller capacitance value, that is, the compensation current amplitude is equal to or approximately equal to the Miller current amplitude, and because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current output by the differential circuit 303 can be used to offset the current generated by the Miller capacitance.

[0198] Embodiment 2

[0199] like Figure 7 As shown, the Miller current suppression method is applied to Figure 3b For the power module shown, the Miller current suppression method includes:

[0200] Step 701: The sampling circuit samples the gate and drain of each power device in at least one power device based on a preset sampling coefficient, and outputs a gate sampling voltage and a drain sampling voltage of each power device in at least one power device.

[0201] Step 702: The differential circuit performs a differential operation on the gate sampling voltage and the drain sampling voltage of each power device in at least one power device, and outputs the drain-gate voltage of each power device in at least one power device.

[0202] Step 703, the differential-multiplication circuit performs differential operation and signal amplification on the drain-gate voltage of each power device in the at least one power device based on a preset differential coefficient and a preset amplification coefficient, and outputs a compensation current to the gate of each power device in the at least one power device respectively;

[0203] It should be noted that the product of the sampling coefficient, the differential coefficient and the amplification coefficient of the sampling circuit is equal to the Miller capacitance value of the power device corresponding to the compensation current, wherein the Miller capacitance value is the capacitance value of the corresponding power device measured in advance when the drain-source voltage is zero. In this way, the amplitude of the compensation current calculated by combining the differential value of the drain-gate voltage and formula 2 is close to the amplitude of the Miller current;

[0204] This is because when the power device is turned on, the potential difference between the source and the drain is very small, generally only a few hundred millivolts or a few volts of voltage drop. Therefore, when the power device is turned on, the Miller capacitance value is close to the capacitance value when the drain-source voltage is zero. Furthermore, when the drain-source voltage is zero, the Miller capacitance value is the largest, which can cover more operating conditions and avoid the problem of insufficient compensation.

[0205] Based on the technical solution in the embodiment, the sampling circuit samples the gate voltage and the drain voltage of the power device; further, the differential circuit performs a differential operation on the gate sampling voltage and the drain sampling voltage, and outputs the drain-gate voltage of each power device in at least one power device. The differential-multiplication circuit performs a differential operation on the drain-gate voltage of each power device in at least one power device, and performs a same-direction proportional amplification, and finally outputs a compensation current.

[0206] Since the product of the sampling coefficient, the differential coefficient and the amplification coefficient is equal to the Miller capacitance value, the compensation current amplitude output by the differential-multiplication circuit is equal to the product of the differential of the drain-gate voltage and the Miller capacitance value, that is, the compensation current amplitude is equal to or approximately equal to the Miller current amplitude. Because the phase of the compensation current is opposite to the phase of the Miller current, the compensation current can be used to offset the current generated by the Miller capacitance.

[0207] Embodiment 3

[0208] like Figure 8 As shown, the Miller current suppression method is applied to Figure 3c For the power module shown, the Miller current suppression method includes:

[0209] In step 801 , the control circuit collects the gate voltage, the drain voltage and the source voltage of each power device in at least one power device, and executes steps 802 and 803 .

[0210] Step 802: The control circuit performs a differential operation on the difference between the gate voltage and the drain voltage of each power device in at least one power device to calculate the drain-gate voltage differential of each power device in at least one power device.

[0211] Step 803 : The control circuit calculates the drain-source voltage of each power device in the at least one power device based on the difference between the source voltage and the drain voltage of each power device in the at least one power device.

[0212] Step 804: The control circuit obtains the Miller capacitance value based on a preset Miller capacitance value-drain-source voltage curve and the drain-source voltage of each power device in at least one power device.

[0213] The Miller capacitance value obtained in step 804 may be equal to the actual capacitance value of the Miller capacitance of the power device in an ideal state.

[0214] Step 805 : The control circuit outputs a compensation current to the gate of each power device in at least one power device based on the product of the Miller capacitance value and the differential value of the drain-gate voltage and a phase opposite to the Miller current.

[0215] Based on the technical solution in this embodiment, the control circuit determines the Miller capacitance value with high accuracy based on the preset Miller capacitance value-drain-source voltage curve; and because the phase of the preset compensation current is opposite to the phase of the Miller current, the compensation current can be used to offset the Miller current and avoid the problem of over-compensation.

[0216] In summary, the embodiments of the present application provide a variety of methods for suppressing Miller current, and the main technical concept is: the control circuit calculates the Miller capacitance value by the Miller capacitance value when the drain-source voltage is zero in advance or based on the drain-source voltage of the power device and the preset Miller capacitance value-drain-source voltage curve; on the other hand, the control circuit calculates the differential of the drain-gate voltage by sampling the drain and gate of the power device, and finally calculates the amplitude of the compensation current according to the Miller capacitance value and the differential of the drain-gate voltage, and outputs the compensation current in combination with the phase opposite to the Miller current;

[0217] In this way, the amplitude of the output compensation current is close to or even equal to the amplitude of the Miller current, and the phase of the compensation current is opposite to the phase of the Miller current, so that the compensation current output by the control circuit can offset the Miller current, thereby suppressing the Miller effect.

[0218] Based on the same technical concept, the embodiment of the present application further provides a chip. The implementation of the chip can refer to the above-mentioned relevant contents about the power module, and the repeated parts will not be repeated. Fig. 9 As shown, the chip 901 is coupled to the memory 902, and the chip 901 may be a digital logic circuit;

[0219] The input end of the digital logic circuit is connected to the source S, drain D and gate G of at least one power device, and the output end of the digital logic circuit is connected to the source S, drain D and gate G of at least one power device. Fig. 9 9031 to 903n) are connected to the gate G of at least one power device. If at least one driver is a plurality of drivers, the plurality of drivers are cascaded;

[0220] Digital logic circuit, used to read and execute program instructions stored in memory 902, so that Figure 6 to Figure 8 Any of the methods shown in is executed, and the specific implementation process is as described above and will not be repeated here;

[0221] Each of the at least one driver is used to amplify the current output by the digital logic circuit to drive the gate G of the power device;

[0222] This is because the current signal output by the digital logic circuit is generally in the milliampere level and needs to be amplified by the driver before it has the energy to drive the power device. The specific number of drivers is determined by the energy requirements of the driving power device and the output energy of the digital logic circuit.

[0223] Exemplarily, the digital logic circuit can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0224] It should be understood that the memory mentioned in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct memory bus random access memory (DR RAM).

[0225] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0226] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0227] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0228] Those skilled in the art should also understand that the circuit structure of the present application can be changed by combination and decomposition without departing from the technical concept of the present application, such as cascading a differentiator and a differentiator to form an operational amplifier circuit, or disassembling a multiplier into a plurality of multipliers in cascade, but the overall amplification factor remains unchanged; or a digital logic chip can be disassembled into several chips in parallel, but the whole still realizes the same function.

[0229] Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A power module, characterized in that: The power module includes a control circuit and at least one power device; The output end of the control circuit is connected to the gate of each power device in the at least one power device, and the input end of the control circuit is connected to the drain and gate of each power device in the at least one power device; The control circuit is used to output a compensation current to the gate of each power device in the at least one power device respectively; The phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the difference between the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device is within a preset range.

2. The power module according to claim 1, characterized in that: The amplitude of the compensation current is calculated by the control circuit according to the Miller capacitance value and the drain-gate voltage of the corresponding power device.

3. The power module according to claim 2, characterized in that: The amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

4. The power module according to claim 2 or 3, characterized in that: The Miller capacitance value is a pre-measured capacitance value of the corresponding power device when the drain-source voltage is zero.

5. The power module according to any one of claims 2 to 4, characterized in that: The control circuit includes a sampling circuit, a differential circuit and a differential circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential circuit, and the output end of the differential circuit constitutes the output end of the control circuit; The sampling circuit is used to sample the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and output a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device; The differential circuit is used to perform differential operation on the gate sampling voltage and the drain sampling voltage of each power device in the at least one power device, and output the drain-gate voltage of each power device in the at least one power device; The differential circuit is used to perform a differential operation on the drain-gate voltage of each power device in the at least one power device based on a differential coefficient, and output a compensation current to the gate of each power device in the at least one power device respectively; wherein the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current.

6. The power module according to any one of claims 2 to 4, characterized in that: The control circuit comprises a sampling circuit, a differential circuit and a differential-multiplication circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential-multiplication circuit, and the output end of the differential-multiplication circuit constitutes the output end of the control circuit; The sampling circuit is used to sample the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and output a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device; The differential circuit is used to perform differential operation on the gate sampling voltage and the drain sampling voltage of each power device in the at least one power device, and output the drain-gate voltage of each power device in the at least one power device; The differential-multiplication circuit is used to perform differential operation and signal amplification on the drain-gate voltage of each power device in the at least one power device based on a preset differential coefficient and a preset amplification coefficient, and output a compensation current to the gate of each power device in the at least one power device respectively; wherein the product of the sampling coefficient of the sampling circuit, the differential coefficient and the amplification coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current.

7. The power module according to claim 2 or 3, characterized in that: The input end of the control circuit is also connected to the source of each power device in the at least one power device.

8. The power module according to claim 7, characterized in that: The Miller capacitance value is obtained by the control circuit based on the drain-source voltage of the corresponding power device and a preset Miller capacitance value-drain-source voltage curve.

9. A Miller current suppression method, characterized in that: The Miller current suppression method is applied to a power module, wherein the power module includes a control circuit and at least one power device; The output end of the control circuit is connected to the gate of each power device in the at least one power device, and the input end of the control circuit is connected to the drain and gate of each power device in the at least one power device; The method comprises: The control circuit outputs a compensation current to the gate of each power device in the at least one power device respectively; The phase of the compensation current is opposite to the phase of the Miller current of the corresponding power device, and the difference between the amplitude of the compensation current and the amplitude of the Miller current of the corresponding power device is within a preset range.

10. The Miller current suppression method according to claim 9, characterized in that: The amplitude of the compensation current is calculated by the control circuit according to the Miller capacitance value and the drain-gate voltage of the corresponding power device.

11. The Miller current suppression method according to claim 10, characterized in that: The amplitude of the compensation current is equal to the product of the Miller capacitance value of the corresponding power device and the differential value of the drain-gate voltage.

12. The Miller current suppression method according to claim 10 or 11, characterized in that: The Miller capacitance value is a pre-measured capacitance value of the corresponding power device when the drain-source voltage is zero.

13. The Miller current suppression method according to any one of claims 10 to 12, characterized in that: The control circuit includes a sampling circuit, a differential circuit and a differential circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential circuit, and the output end of the differential circuit constitutes the output end of the control circuit; The control circuit outputs a compensation current to the gate of each power device in the at least one power device, respectively, including: The sampling circuit samples the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and outputs a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device; The differential circuit performs differential operation on the gate sampling voltage and the drain sampling voltage of each power device in the at least one power device, and outputs the drain-gate voltage of each power device in the at least one power device; The differential circuit performs a differential operation on the drain-gate voltage of each power device in the at least one power device based on a differential coefficient, and outputs a compensation current to the gate of each power device in the at least one power device respectively; wherein the product of the sampling coefficient and the differential coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current.

14. The Miller current suppression method according to any one of claims 10 to 12, characterized in that: The control circuit comprises a sampling circuit, a differential circuit and a differential-multiplication circuit; wherein the input end of the sampling circuit constitutes the input end of the control circuit, the differential circuit is connected between the sampling circuit and the differential-multiplication circuit, and the output end of the differential-multiplication circuit constitutes the output end of the control circuit; The control circuit outputs a compensation current to the gate of each power device in the at least one power device, respectively, including: The sampling circuit samples the gate and drain of each power device in the at least one power device based on a preset sampling coefficient, and outputs a gate sampling voltage and a drain sampling voltage of each power device in the at least one power device; The differential circuit performs differential operation on the gate sampling voltage and the drain sampling voltage of each power device in the at least one power device, and outputs the drain-gate voltage of each power device in the at least one power device; The differential-multiplication circuit performs differential operation and signal amplification on the drain-gate voltage of each power device in the at least one power device based on a preset differential coefficient and a preset amplification coefficient, and outputs a compensation current to the gate of each power device in the at least one power device respectively; wherein the product of the sampling coefficient of the sampling circuit, the differential coefficient and the amplification coefficient is equal to the Miller capacitance value of the power device corresponding to the compensation current.

15. The Miller current suppression method according to claim 10 or 11, characterized in that: The input end of the control circuit is also connected to the source of each power device in the at least one power device, and the Miller capacitance value is obtained by the control circuit based on the drain-source voltage of the corresponding power device and a preset Miller capacitance value-drain-source voltage curve.

Images