Driving circuit and driving system

Abstract

The utility model discloses a drive circuit and a drive system, comprising a drive module, the drive module comprises a first drive branch and at least one second drive branch, the first drive branch is connected with a power device, and each second drive branch is respectively connected with the power device; the voltage detection module is connected with the power device and is used for detecting a voltage value between the grid electrode of the power device and the source electrode of the power device; the control module is connected with the voltage detection module and the driving module, and the control module is used for controlling the first driving branch to be switched on to drive the power device when the voltage value is determined not to be within the Miller platform voltage range, and controlling the second driving branch to be switched on to drive the power device when the voltage value is determined to be within the Miller platform voltage range. And controlling the first driving branch and the at least one second driving branch to be switched on simultaneously so as to drive the power device. The driving circuit can effectively accelerate the process of the Miller platform period, shorten the duration of the Miller platform, further reduce the switching time of a power device and improve the system efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a driving circuit and a driving system. Background Art

[0002] In the related technology, the energy of electric vehicles is provided by high-voltage batteries, and the power module composed of power devices IGBT (Insulated Gate Bipolar Transistor) or SiC MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) converts its direct current into three-phase alternating current to drive the motor. The switching state of the power device in the power module is controlled by the drive signal sent by the microprocessor in the motor control system after being isolated and amplified by the drive circuit composed of the gate driver and related components. That is, the drive circuit converts the drive signal sent by the microprocessor into a high-voltage, high-current pulse to control the gate of the IGBT or MOSFET to turn it on or off.

[0003] However, due to the existence of Miller capacitance in power devices, there is a Miller platform in the shutdown process and the turn-on process of the power devices. The power devices will generate losses due to the overlap of voltage and current during switching transients. The Miller platform period prolongs the switching time and increases the loss. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a driving circuit, which can effectively accelerate the process of the Miller platform period, shorten the duration of the Miller platform, and thus reduce the switching time of the power device and improve the system efficiency.

[0005] A second purpose of the present invention is to provide a driving system.

[0006] In order to solve the above problems, the first aspect of the utility model provides a driving circuit, including: a driving module, the driving module including a first driving branch and at least one second driving branch, the first driving branch is connected to the power device, and each second driving branch is respectively connected to the power device; a voltage detection module, the voltage detection module is connected to the power device, and is used to detect the voltage value between the gate of the power device and the source of the power device; a control module, the control module is connected to the voltage detection module and the driving module, and the control module is used to control the first driving branch to be turned on to drive the power device when it is determined that the voltage value is not within the Miller platform voltage range, and when it is determined that the voltage value is within the Miller platform voltage range, control the first driving branch and at least one second driving branch to be turned on at the same time to drive the power device.

[0007] According to the driving circuit of the embodiment of the utility model, at least one second driving branch is added on the basis of the original branch of the driving module, so that when it is determined that the voltage value is within the Miller platform voltage range, the control module controls the first driving branch and at least one second driving branch to be turned on at the same time, thereby increasing the driving current of the power device, thereby effectively accelerating the process of the Miller platform period, shortening the duration of the Miller platform, reducing the switching time of the power device, and improving the system efficiency.

[0008] In some embodiments, the driving module includes a driver chip, which includes a PWM signal receiving end, a power supply end and a driving connection end, the power supply end is suitable for connecting a driving power supply, and the driving connection end is connected to the input end of the first driving branch and the input end of each second driving branch; the control module includes a PWM signal output end, the PWM signal output end is connected to the PWM signal receiving end, and the PWM signal output end is used to output the PWM signal sent by the control module.

[0009] In some embodiments, the driver chip also includes: a signal processing unit, which is connected to the PWM signal receiving end and is used to perform signal processing on the PWM signal; a switch unit, a first end of the switch unit is connected to the power supply end, a second end of the switch unit is connected to the drive connection end, and a control end of the switch unit is connected to the signal processing unit.

[0010] In some embodiments, the first driving branch includes: a first resistor, a first end of the first resistor is connected to the driving connection end, and a second end of the first resistor is connected to the gate of the power device.

[0011] In some embodiments, each second driving branch includes: a MOS tube, the source of which is connected to the driving connection end; a second resistor, the first end of which is connected to the drain of the MOS tube, and the second end of which is connected to the gate of the power device; a third resistor, the first end of which is connected to the source of the MOS tube and the driving connection end, and the second end of which is connected to the gate of the MOS tube; and a fourth resistor, the first end of which is connected to the gate of the MOS tube, and the second end of which is connected to the voltage detection module.

[0012] In some embodiments, the control module also includes a control signal output terminal for outputting a drive control signal to control the on / off state of the MOS tube; the voltage detection module includes an isolation chip, a first input terminal of the isolation chip is connected to the control signal output terminal, and a first output terminal of the isolation chip is connected to the second end of each fourth resistor.

[0013] In some embodiments, the control module also includes an AD conversion end, which is connected to the second output end of the isolation chip; the voltage detection module also includes a detection unit and an amplification unit, the first end of the detection unit is connected to the gate of the power device, the second end of the detection unit is connected to the source of the power device, the output end of the amplification unit is connected to the second input end of the isolation chip, the first input end of the amplification unit is connected to the first end of the detection unit, and the second input end of the amplification unit is connected to the second end of the detection unit.

[0014] In some embodiments, the amplification unit includes: an operational amplifier, the output end of the operational amplifier is connected to the second input end of the isolation chip; a fifth resistor, the first end of the fifth resistor is connected to the first end of the detection unit, and the second end of the fifth resistor is connected to the first input end of the operational amplifier; a sixth resistor, the first end of the sixth resistor is connected to the second end of the detection unit, and the second end of the sixth resistor is connected to the second input end of the operational amplifier; a seventh resistor, the first end of the seventh resistor is connected to the second end of the fifth resistor and the first input end of the operational amplifier, and the second end of the seventh resistor is grounded; an eighth resistor, the first end of the eighth resistor is connected to the second end of the sixth resistor and the second input end of the operational amplifier, and the second end of the eighth resistor is connected to the output end of the operational amplifier and the second input end of the isolation chip.

[0015] In some embodiments, the detection unit includes: a detection resistor, a first end of the detection resistor is connected to the gate of the power device, and a second end of the detection resistor is connected to the source of the power device.

[0016] A second aspect of the present invention provides a driving system, including: a power device; and the driving circuit described in the above embodiment, wherein the driving circuit is used to drive the power device to turn on or off.

[0017] According to the drive system of the embodiment of the utility model, the use of the above-mentioned drive circuit can effectively accelerate the process of the Miller platform period, shorten the duration of the Miller platform, and thus reduce the switching time of the power device and improve the system efficiency.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 It is a schematic diagram of the voltage and current curves during the conduction process of the power device;

[0021] Figure 2 is a structural block diagram of a driving circuit according to an embodiment of the utility model;

[0022] Figure 3 is a topological schematic diagram of a driving circuit according to an embodiment of the utility model;

[0023] Figure 4 is a topological schematic diagram of a driving circuit according to another embodiment of the utility model;

[0024] Figure 5 It is a structural block diagram of a driving system according to an embodiment of the utility model.

[0025] Reference numerals:

[0026] Drive system 1000;

[0027] Driving circuit 100; power device 200;

[0028] Driving module 10; voltage detection module 20; control module 30; first driving branch 101; second driving branch 102;

[0029] Driving chip 1; isolation chip 2; detection unit 3; amplification unit 4; signal processing unit 11; switch unit 12;

[0030] A first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a detection resistor R9, a MOS tube Q1, and an operational amplifier U1. DETAILED DESCRIPTION

[0031] The embodiments of the present utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present utility model are described in detail below.

[0032] IGBT and MOSFET are voltage-controlled devices, and their driving methods are different from those of current-controlled devices such as triodes. However, they actually also require current during the switching process. Taking MOSFET as an example, because there are parasitic capacitances Cgd, Cgs, and Cds between each pole, the MOSFET conduction condition is that the Vgs voltage reaches at least the threshold voltage Vgs (th), which is achieved by charging the Cgs capacitance through the gate charge. When the MOS tube is fully turned on, it is not necessary to provide current to it. The three parasitic capacitance parameter values ​​are generally given in the specification book in the form of input capacitance Ciss, output capacitance Coss, and reverse transfer capacitance Crss, and the corresponding relationship is: Ciss = Cgs + Cgd, Coss = Cds + Cgd, Crss = Cgd, and Cgd is the Miller capacitance.

[0033] During the charging process of the MOSFET gate, Vgs increases with the increase of gate charge at the beginning, but when Vgs increases to the Miller platform voltage, even if the gate charge continues to increase, Vgs remains unchanged because the increased gate charge is used to charge the Cgd capacitor. When the MOS tube is cut off, the drain voltage charges Cgd, and the voltage polarity of Cgd is positive at the top and negative at the bottom; when the MOS tube enters the Miller platform, most of the gate charge is used to charge Cgd, but the polarity is opposite to the drain charge, so it can also be understood as a reverse discharge of Cgd, which eventually makes the Vgd voltage change from negative to positive. When the condition of Vgs-Vgs(th)>Uds is reached, the Miller platform period of the MOS tube ends. In the Miller platform interval, Vds continues to decrease, and the duration of the Miller platform is the time for the Vds voltage to drop from the maximum value to the minimum value. It can be seen that the Miller platform time is positively correlated with the size of the capacitor Cgd.

[0034] The gate drive process can be understood as the charging and discharging process of the gate driver on the input capacitance of the power device, such as Figure 1As shown, during the turn-on process of MOSFET, the gate drive current Ig continues to decrease. When the gate-source voltage Vgs reaches the turn-on voltage threshold Vgs(th), MOSFET will enter the turn-on state, the drain-source voltage Vds begins to decrease, and the drain current Id begins to rise. However, after Vgs rises to the Miller platform voltage Va, it will continue to rise for a period of time, and the gate drive current Ig remains basically unchanged. At this time, Id has reached the maximum, and Vds continues to decrease until the Miller capacitor is fully charged. Vgs continues to rise to the value of the drive voltage Vgg, and the gate drive current Ig drops to zero. At this time, MOSFET enters the saturation region, Vds drops completely, and the turn-on process ends. Therefore, since the Miller capacitor prevents the rise of Vgs, it also prevents the decline of Vds, which causes the loss time to be prolonged and increases the loss.

[0035] The following describes a driving circuit according to an embodiment of the utility model with reference to the accompanying drawings. Figure 2 and Figure 3 As shown, the driving circuit 100 includes a driving module 10 , a voltage detection module 20 and a control module 30 .

[0036] Among them, Figure 2 As shown in or 3, the driving module 10 includes a first driving branch 101 and at least one second driving branch 102, the first driving branch 101 is connected to the power device 200, and each second driving branch 102 is respectively connected to the power device 200, that is, the first driving branch 101 and each second driving branch 102 are in a parallel relationship; the voltage detection module 20 is connected to the power device 200, and is used to detect the voltage value between the gate of the power device 200 and the source of the power device 200; the control module 30 is connected to the voltage detection module 20 and the driving module 10, and the control module 30 is used to control the first driving branch 101 to be turned on to drive the power device 200 when it is determined that the voltage value is not within the Miller platform voltage range, and when it is determined that the voltage value is within the Miller platform voltage range, control the first driving branch 101 and at least one second driving branch 102 to be turned on at the same time to drive the power device 200.

[0037] Specifically, in order to solve the problem that the Miller platform period prolongs the switching time of the power device and increases the loss, the present application adds at least one second driving branch 102 on the basis of the original first driving branch 101 of the driving module 10. Based on this, during the switching process of the power device 200, the voltage value between the gate of the power device 200 and the source of the power device 200 is detected by the voltage detection module 20 to obtain the Miller platform voltage range, so that the control module 30 drives and controls the driving module 10 based on the voltage value and the Miller platform voltage range. Specifically, when it is determined that the voltage value is not within the Miller platform voltage range, the first driving branch 101 is controlled to be turned on to drive the power device 200, and when it is determined that the voltage value is within the Miller platform voltage range, the first driving branch 101 is controlled to be turned on to drive the power device 200. When the voltage of the platform is within the range, the first driving branch 101 and at least one second driving branch 102 are controlled to be turned on at the same time to drive the power device 200. That is to say, at least one second driving branch 102 only works during the Miller platform period, and at least one second driving branch 102 will not affect the circuit operation in other time periods. Therefore, during the Miller platform period, the first driving branch 101 and at least one second driving branch 102 jointly provide a driving current for the gate of the power device, which can effectively accelerate the progress of the Miller platform period, shorten the duration of the Miller platform, and thus reduce the switching time of the power device and improve the system efficiency. In addition, the present application requires fewer components and has low cost, and has no effect on the circuit function outside the Miller platform period.

[0038] Among them, at least one second driving branch 102 can be one or more, and there is no limitation on this. In addition, under the condition that there are multiple second driving branches 102, the control module 30 can control some or all of the second driving branches 102 to be turned on according to actual needs, so as to increase the driving current of the power device 200, accelerate the process of the Miller platform period, and shorten the duration of the Miller platform. According to the driving circuit 100 of the embodiment of the utility model, at least one second driving branch 102 is added on the basis of the original branch of the driving module 10, so that when it is determined that the voltage value is within the Miller platform voltage range, the control module 30 controls the first driving branch 101 and at least one second driving branch 102 to jointly play a driving role to increase the driving current of the power device, thereby effectively accelerating the process of the Miller platform period, shortening the duration of the Miller platform, reducing the switching loss of the power device, and improving the system efficiency.

[0039] In some embodiments, reference Figure 3 As shown, the driving module 10 includes a driver chip 1, the driver chip 1 includes a PWM signal receiving terminal, a power supply terminal VCC2 and a driving connection terminal OUTH, and the control module 30 includes a PWM signal output terminal PH.

[0040] Among them, the power supply terminal VCC2 is suitable for connecting the driving power supply to power the driving module 10; the driving connection terminal OUTH is connected to the input terminal of the first driving branch 101 and the input terminal of each second driving branch 102; the PWM signal output terminal PH is connected to the PWM signal receiving terminal, and the PWM signal output terminal PH is used to output the PWM signal sent by the control module 30, that is, the PWM signal output terminal PH is a signal output terminal for controlling the power device 200 to be turned on or off. Based on this, the driver chip 1 can turn on or off the first driving branch 101 according to the PWM signal provided by the control module 30. For example, when the PWM signal is a PWM_ON signal, the driver chip 1 drives the loop where the first driving branch 101 is located to be turned on, so as to provide a driving current for the power device 200 and start the conduction process.

[0041] In some embodiments, reference Figure 3 As shown, the driver chip 1 includes a signal processing unit 11 and a switch unit 12 .

[0042] Among them, the signal processing unit 11 is connected to the PWM signal receiving end for processing the PWM signal; the first end of the switch unit 12 is connected to the power supply end VCC2, the second end of the switch unit 12 is connected to the drive connection end OUTH, and the control end of the switch unit 12 is connected to the signal processing unit 11.

[0043] Specifically, the PWM signal emitted by the control module 30 enters the signal processing unit 11 from the PWM signal receiving end. The signal processing unit 11 provides isolation, amplification, direct-through interlocking and other processing for the received PWM signal. The PWM signal is processed by the signal processing unit 11 and output to the control end of the switch unit 12. Thus, the switch unit 12 is turned on or off based on the signal of the controller, and then turns on or off the first drive branch 101, so as to control whether the power device is turned on.

[0044] Exemplarily, when the power device 200 needs to be driven to turn on, the control module 30 sends a PWM_ON signal to the signal processing unit 11 of the driver chip 1. The PWM_ON signal is output to the control end of the switch unit 12 after being isolated, amplified, and directly interlocked by the signal processing unit 11, so as to turn on the switch unit 12, thereby causing the loop where the first drive branch 101 is located to be turned on, so as to provide a driving current for the power device 200 and start the conduction process; and the shutdown process of the power device 200 is similar to the above-mentioned conduction process, which will not be described in detail here.

[0045] In some embodiments, reference Figure 3 As shown, the first driving branch 101 includes a first resistor R1.

[0046] The first end of the first resistor R1 is connected to the driving connection terminal OUTH, and the second end of the first resistor R1 is connected to the gate of the power device 200 . That is, the first resistor R1 is used as a driving resistor for the driver chip 1 to drive the switch of the power device 200 .

[0047] In some embodiments, reference Figure 3 As shown, each second driving branch 102 includes a MOS transistor Q1, a second resistor R2, a third resistor R3 and a fourth resistor R4.

[0048] Among them, the source of the MOS tube Q1 is connected to the driving connection terminal OUTH; the first end of the second resistor R2 is connected to the drain of the MOS tube Q1, and the second end of the second resistor R2 is connected to the gate of the power device 200; the first end of the third resistor R3 is connected to the source of the MOS tube Q1 and the driving connection terminal OUTH, and the second end of the third resistor R3 is connected to the gate of the MOS tube Q1; the first end of the fourth resistor R4 is connected to the gate of the MOS tube Q1, and the second end of the fourth resistor R4 is connected to the voltage detection module 20.

[0049] Specifically, based on the above circuit topology, the conduction and cutoff of the MOS tube Q1 can control whether the branch that shortens the Miller platform time is on, and whether the second drive branch 102 is on. That is to say, when the voltage value is within the Miller platform voltage range, the MOS tube Q1 is turned on, and the loop where the second drive branch 102 is located is turned on, so that the second drive branch 102 and the first drive branch 101 jointly provide current for the power device 200, which can accelerate the process of the Miller platform period and shorten the Miller platform time; when the voltage value is not within the Miller platform voltage range, the MOS tube Q1 is turned off, and the loop where the second drive branch 102 is located is disconnected, and only the first drive branch 101 provides current for the power device 200. Among them, the third resistor R3 and the fourth resistor R4 are used to set the drive voltage of the MOS tube Q1, and the second resistor R2 is used as the drive resistor of the second drive branch 102.

[0050] In some embodiments, reference Figure 3 As shown, the control module 30 further includes a control signal output terminal PM, and the voltage detection module 20 includes an isolation chip 2 .

[0051] Among them, the control signal output terminal PM is used to output a driving control signal to control the on / off of the MOS tube Q1; the first input terminal of the isolation chip 2 is connected to the control signal output terminal PM, and the first output terminal of the isolation chip 2 is connected to the second end of each fourth resistor R4 to drive each second driving branch 102 to be on or off.

[0052] Exemplarily, when the control module 30 determines that the voltage value is not within the Miller platform voltage range, the control signal output terminal PM outputs a driving control signal of a high level, which is received by the isolation chip 2 and controls the MOS tube Q1 to be turned off, then the second driving branch 102 is disconnected, that is, only the first driving branch 101 provides current to the power device 200, and the second driving branch 102 does not participate in the turn-on process of the power device 200; when the control module 30 determines that the voltage value is within the Miller platform voltage range, the control signal output terminal PM outputs a driving control signal of a low level, which is received by the isolation chip 2 and controls the MOS tube Q1 to be turned on, then the second driving branch 102 is turned on, and together with the first driving branch 101, provides current to the power device 200, thereby accelerating the process of the Miller platform period and shortening the Miller platform time. Repeating the above steps can achieve the acceleration of the Miller platform period process during the turn-on of the power device 200.

[0053] In addition, in the software design of the control module 30, a hysteresis function may be set for the control signal output terminal PM, thereby effectively filtering out signal interference and improving system reliability.

[0054] In some embodiments, reference Figure 4 As shown, the control module 30 further includes an AD conversion terminal, and the voltage detection module 20 further includes a detection unit 3 and an amplification unit 4.

[0055] Among them, the AD conversion end is connected to the second output end of the isolation chip 2; the first end of the detection unit 3 is connected to the gate of the power device 200, and the second end of the detection unit 3 is connected to the source of the power device 200; the output end of the amplification unit 4 is connected to the second input end of the isolation chip 2, the first input end of the amplification unit 4 is connected to the first end of the detection unit 3, and the second input end of the amplification unit 4 is connected to the second end of the detection unit 3.

[0056] Specifically, when the driving power device 200 is turned on, the detection unit 3 detects the voltage value between the gate and the source of the power device, and sends the detected voltage value, i.e., Vgs, to the amplification unit 4 for amplification processing and then to the control module 30 via the isolation chip 2. The AD conversion end of the control module 30 detects Vgs and calculates the Vgs voltage change rate dv / dt. Because the voltage change rate of Vgs during the Miller platform is much smaller than that in other time periods, the Miller platform voltage range can be obtained.

[0057] It should be noted that when the operating conditions of the control module 30 change, for example, when the temperature of the power device rises or falls, the Miller platform voltage range may change. Therefore, the Vgs voltage value detected by the AD conversion end should be used to timely reconfirm the Miller platform voltage range, i.e., the upper and lower limit voltage values ​​of the Miller platform, so that the relevant circuits can better serve the Miller platform period.

[0058] In addition, after several detection cycles, the control module 30 can obtain a more accurate Miller platform voltage range, that is, the upper and lower limit voltage values ​​of the Miller platform. Therefore, when the working state of the control module 30 does not change, the Miller platform voltage range can no longer be detected to save the resource usage of the microprocessor.

[0059] In some embodiments, reference Figure 4 As shown, the amplifying unit 4 includes an operational amplifier U1 , a fifth resistor R5 , a sixth resistor R6 , a seventh resistor R7 and an eighth resistor R8 .

[0060] Among them, the output end of the operational amplifier U1 is connected to the second input end of the isolation chip 2; the first end of the fifth resistor R5 is connected to the first end of the detection unit 3, and the second end of the fifth resistor R5 is connected to the first input end of the operational amplifier U1; the first end of the sixth resistor R6 is connected to the second end of the detection unit 3, and the second end of the sixth resistor R6 is connected to the second input end of the operational amplifier U1; the first end of the seventh resistor R7 is connected to the second end of the fifth resistor R5 and the first input end of the operational amplifier U1, and the second end of the seventh resistor R7 is grounded; the first end of the eighth resistor R8 is connected to the second end of the sixth resistor R6 and the second input end of the operational amplifier U1, and the second end of the eighth resistor R8 is connected to the output end of the operational amplifier U1 and the second input end of the isolation chip 2. In some embodiments, reference Figure 4 As shown, the detection unit 3 includes a detection resistor R9,

[0061] The first end of the detection resistor R9 is connected to the gate of the power device 200 , and the second end of the detection resistor R9 is connected to the source of the power device 200 .

[0062] Specifically, refer to Figure 3 and Figure 4 As shown, during the conduction process of the power device 200, the differential amplifier composed of the operational amplifier U1, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 continuously processes the gate-source voltage value Vgs according to the corresponding proportion, that is, the voltage across the detection resistor R9, and sends it to the AD conversion end of the control module 30 through the isolation chip 2 for detection, and calculates the voltage change rate dv / dt of Vgs. Because the voltage change rate of Vgs during the Miller platform is much smaller than that in other time periods, the voltage values ​​of the upper and lower limits of the Miller platform, that is, the Miller platform voltage range, can be obtained.

[0063] Furthermore, if the gate-source voltage value Vgs of the power device output by the differential amplifier is within the Miller platform voltage range, that is, Vgs is in the Miller platform interval, the control signal output terminal PM of the control module 30 outputs a low level, and the drive control loop composed of the power supply terminal VCC2, the drive connection terminal OUTH, the MOS tube Q1 and the second resistor R2 is turned on, then the second drive branch 102 is turned on, and together with the drive loop composed of the power supply terminal VCC2, the drive connection terminal OUTH and the first resistor R1, provides a drive current for the gate of the power device, thereby accelerating the process of the Miller platform period and shortening the platform time.

[0064] With the exit of the Miller platform period, the gate-source voltage value Vgs of the power device output by the differential amplifier exceeds the Miller platform voltage range, the control signal output terminal PM of the control module 30 outputs a high level, and the drive control loop composed of the power supply terminal VCC2, the drive connection terminal OUTH, the MOS tube Q1 and the second resistor R2 is disconnected, then the second drive branch 102 is disconnected, and only the drive loop composed of the power supply terminal VCC2, the drive connection terminal OUTH and the first resistor R1 provides drive current for the gate of the power device 200.

[0065] The second embodiment of the utility model provides a drive system, referring to Figure 5 As shown, the driving system 1000 includes a power device 200 and a driving circuit 100 .

[0066] The driving circuit 100 is used to drive the power device 200 to turn on or off.

[0067] According to the drive system 1000 of the embodiment of the utility model, the above-mentioned drive circuit 100 is adopted, which can effectively accelerate the process of the Miller platform period, shorten the duration of the Miller platform, and thus reduce the switching time of the power device 200 and improve the system efficiency.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0069] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A driving circuit, characterized in that: include: A driving module, the driving module comprising a first driving branch and at least one second driving branch, the first driving branch is connected to the power device, and each second driving branch is respectively connected to the power device; A voltage detection module, the voltage detection module is connected to the power device and is used to detect a voltage value between a gate of the power device and a source of the power device; A control module, wherein the control module is connected to the voltage detection module and the drive module, and the control module is used to control the first drive branch to be turned on to drive the power device when it is determined that the voltage value is not within the Miller platform voltage range, and to control the first drive branch and at least one second drive branch to be turned on simultaneously to drive the power device when it is determined that the voltage value is within the Miller platform voltage range.

2. The driving circuit according to claim 1, characterized in that: The driving module includes a driver chip, and the driver chip includes a PWM signal receiving end, a power supply end and a driving connection end, the power supply end is suitable for connecting a driving power supply, and the driving connection end is connected to an input end of the first driving branch and an input end of each second driving branch; The control module comprises a PWM signal output terminal, the PWM signal output terminal is connected to the PWM signal receiving terminal, and the PWM signal output terminal is used to output the PWM signal sent by the control module.

3. The driving circuit according to claim 2, characterized in that: The driver chip further includes: A signal processing unit, connected to the PWM signal receiving end, and configured to perform signal processing on the PWM signal; A switch unit, wherein a first end of the switch unit is connected to the power supply end, a second end of the switch unit is connected to the drive connection end, and a control end of the switch unit is connected to the signal processing unit.

4. The driving circuit according to claim 2 or 3, characterized in that: The first driving branch comprises: A first resistor, wherein a first end of the first resistor is connected to the driving connection end, and a second end of the first resistor is connected to the gate of the power device.

5. The driving circuit according to claim 2 or 3, characterized in that: Each second driving branch comprises: A MOS tube, wherein the source of the MOS tube is connected to the driving connection end; a second resistor, wherein a first end of the second resistor is connected to the drain of the MOS tube, and a second end of the second resistor is connected to the gate of the power device; a third resistor, wherein a first end of the third resistor is connected to the source of the MOS tube and the driving connection end, and a second end of the third resistor is connected to the gate of the MOS tube; A fourth resistor, wherein a first end of the fourth resistor is connected to the gate of the MOS tube, and a second end of the fourth resistor is connected to the voltage detection module.

6. The driving circuit according to claim 5, characterized in that: The control module also includes a control signal output terminal for outputting a driving control signal to control the on / off state of the MOS tube; The voltage detection module includes an isolation chip, a first input terminal of the isolation chip is connected to the control signal output terminal, and a first output terminal of the isolation chip is connected to the second terminal of each fourth resistor.

7. The driving circuit according to claim 6, characterized in that: The control module also includes an AD conversion terminal, which is connected to the second output terminal of the isolation chip; The voltage detection module also includes a detection unit and an amplification unit, the first end of the detection unit is connected to the gate of the power device, the second end of the detection unit is connected to the source of the power device, the output end of the amplification unit is connected to the second input end of the isolation chip, the first input end of the amplification unit is connected to the first end of the detection unit, and the second input end of the amplification unit is connected to the second end of the detection unit.

8. The driving circuit according to claim 7, characterized in that: The amplification unit comprises: An operational amplifier, wherein an output terminal of the operational amplifier is connected to a second input terminal of the isolation chip; a fifth resistor, wherein a first end of the fifth resistor is connected to the first end of the detection unit, and a second end of the fifth resistor is connected to the first input end of the operational amplifier; a sixth resistor, wherein a first end of the sixth resistor is connected to the second end of the detection unit, and a second end of the sixth resistor is connected to the second input end of the operational amplifier; a seventh resistor, wherein a first end of the seventh resistor is connected to the second end of the fifth resistor and the first input end of the operational amplifier, and a second end of the seventh resistor is grounded; An eighth resistor, wherein a first end of the eighth resistor is connected to a second end of the sixth resistor and a second input end of the operational amplifier, and a second end of the eighth resistor is connected to an output end of the operational amplifier and a second input end of the isolation chip.

9. The driving circuit according to claim 7, characterized in that: The detection unit comprises: A detection resistor, wherein a first end of the detection resistor is connected to the gate of the power device, and a second end of the detection resistor is connected to the source of the power device.

10. A drive system, characterized in that: include: Power devices; The drive circuit according to any one of claims 1 to 9, wherein the drive circuit is used to drive the power device to turn on or off.

Images