Driving circuit and driving system

Abstract

The utility model discloses a driving circuit and a driving system, and the driving circuit comprises a first driving module which comprises a driver chip and a first driving branch, and the driver chip is used for driving the first driving branch to be switched on or switched off; 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 second driving module comprises a microprocessor and at least one second driving branch, each second driving branch is connected with the power device after being connected with the first driving branch in parallel, the microprocessor is connected with the voltage detection module, and the microprocessor is used for driving the second driving branch to be switched on or switched off; and the control module is connected with the driver chip and the microprocessor. By adopting the driving circuit, the process of a Miller platform period can be effectively accelerated, the duration of the Miller platform is shortened, the switching time of a power device is further reduced, and the system efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of drive systems, in particular to a drive circuit and a drive 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 emitted 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 emitted 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 is a driving circuit, comprising: a first driving module, the first driving module comprising a driver chip and a first driving branch, the driver chip is used to drive the first driving branch to be turned on or off; 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 second driving module, the second driving module comprises a microprocessor and at least one second driving branch, each second driving branch is connected to the power device in parallel with the first driving branch, the microprocessor is connected to the voltage detection module, and the microprocessor is used to drive the second driving branch to be turned on or off; a control module, the control module is connected to the driver chip and the microprocessor; wherein, when it is determined that the voltage value is not within the Miller platform voltage range, the first driving branch is turned on to drive the power device, and when it is determined that the voltage value is within the Miller platform voltage range, the first driving branch and at least one second driving branch are turned on at the same time to drive the power device.

[0007] According to the drive circuit of the utility model, at least one second drive branch is added on the basis of the original first drive branch, so that when it is determined that the voltage value is within the Miller platform voltage range, the control module controls the first drive branch and at least one second drive branch to be turned on at the same time through the driver chip and the microprocessor, thereby increasing the drive 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 driver chip includes a PWM signal receiving end, a power supply end and a drive connection end, the power supply end is suitable for connecting a drive power supply, and the drive connection end is connected to the input end of the first drive branch and the input end of each second drive 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 serves as the control end of the second driving branch for receiving a driving control signal regarding the MOS tube.

[0012] In some embodiments, the second driving module further includes: a comparison unit, a first end of the comparison unit is connected to the microprocessor, and a second end of the comparison unit is connected to the output end of the voltage detection module; an inverting unit, an input end of the inverting unit is connected to the third end of the comparison unit, and an output end of the inverting unit is connected to the control end of each second driving branch.

[0013] In some embodiments, the microprocessor includes an AD conversion end, a first signal output port and a second signal output port, the AD conversion end is connected to the output end of the voltage detection module, and the microprocessor is used to output a first voltage signal and a second voltage signal according to the voltage value; the comparison unit includes: a first comparison subunit, the same-direction input end of the first comparison subunit is connected to the first signal output port to receive the first voltage signal, the reverse input end of the first comparison subunit is connected to the output end of the voltage detection module, and the output end of the first comparison subunit is connected to the input end of the inverting unit; a second comparison subunit, the reverse input end of the second comparison subunit is connected to the second signal output port to receive the second voltage signal, the same-direction input end of the second comparison subunit is connected to the output end of the voltage detection module, and the output end of the second comparison subunit is connected to the output end of the first comparison subunit and the input end of the inverting unit.

[0014] In some embodiments, the first comparison subunit includes: a first comparator, wherein the output end of the first comparator is connected to the input end of the inverting unit, and the inverting input end of the first comparator is connected to the output end of the voltage detection module; a fifth resistor, wherein the first end of the fifth resistor is connected to the output end of the first comparator and the input end of the inverting unit, and the second end of the fifth resistor is connected to the same-direction input end of the first comparator; a sixth resistor, wherein the first end of the sixth resistor is connected to the first signal output port, and the second end of the sixth resistor is connected to the second end of the fifth resistor and the same-direction input end of the first comparator; and a first capacitor, wherein the first end of the first capacitor is connected to the first end of the sixth resistor and the first signal output port, and the second end of the first capacitor is grounded.

[0015] In some embodiments, the second comparison subunit includes: a second comparator, the output end of the second comparator is connected to the output end of the first comparator and the input end of the inverting unit, and the inverting input end of the second comparator is connected to the second signal output port; a seventh resistor, the first end of the seventh resistor is connected to the same-direction input end of the second comparator, and the second end of the seventh resistor is connected to the output end of the voltage detection module; an eighth resistor, the first end of the eighth resistor is connected to the output end of the second comparator, and the second end of the eighth resistor is connected to the first end of the seventh resistor and the same-direction input end of the second comparator; a second capacitor, the first end of the second capacitor is connected to the inverting input end of the second comparator and the second signal output port, and the second end of the second capacitor is grounded.

[0016] In some embodiments, the voltage detection module includes: a detection unit, a first end of the detection unit is connected to the gate of the power device, and a second end of the detection unit is connected to the source of the power device; an amplification unit, an output end of the amplification unit is connected to the AD conversion end, a first input end of the amplification unit is connected to the first end of the detection unit, and a second input end of the amplification unit is connected to the second end of the detection unit.

[0017] In some embodiments, the amplification unit includes: an operational amplifier, the output end of the operational amplifier is connected to the AD conversion end; a ninth resistor, the first end of the ninth resistor is connected to the first end of the detection unit, and the second end of the ninth resistor is connected to the first input end of the operational amplifier; a tenth resistor, the first end of the tenth resistor is connected to the second end of the detection unit, and the second end of the tenth resistor is connected to the second input end of the operational amplifier; an eleventh resistor, the first end of the eleventh resistor is connected to the second end of the ninth resistor and the first input end of the operational amplifier, and the second end of the eleventh resistor is grounded; a twelfth resistor, the first end of the twelfth resistor is connected to the second end of the tenth resistor and the second input end of the operational amplifier, and the second end of the twelfth resistor is connected to the output end of the operational amplifier and the AD conversion end.

[0018] 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.

[0019] 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.

[0020] According to the drive system of the utility model, through the drive circuit of the above embodiment, the process of the Miller platform period can be effectively accelerated, the duration of the Miller platform can be shortened, and the switching time of the power device can be reduced, thereby improving the system efficiency.

[0021] 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

[0022] 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:

[0023] Figure 1 It is a schematic diagram of the gate charging curve of the power device;

[0024] Figure 2 It is a schematic diagram of the voltage and current curves during the conduction process of the power device;

[0025] Figure 3 is a topological schematic diagram of a driving circuit according to an embodiment of the utility model;

[0026] Figure 4 is a topological schematic diagram of a driving circuit according to another embodiment of the utility model;

[0027] Figure 5 It is a schematic diagram of a driving system according to an embodiment of the utility model.

[0028] Reference numerals:

[0029] Driving system 1000; driving circuit 900; power device 800;

[0030] First driving module 1; voltage detection module 2; second driving module 3; control module 4; driver chip 11; first driving branch 12; detection unit 21; amplification unit 22; microprocessor 31; second driving branch 32; comparison unit 33; inverting unit 34; signal processing unit 111; switch unit 112; first comparison subunit 331; second comparison subunit 332;

[0031] 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 ninth resistor R9; a tenth resistor R10; an eleventh resistor R11; a twelfth resistor R12; a detection resistor Rge; a MOS tube Q1; a first comparator U1; a second comparator U2; a first capacitor C1; a second capacitor C2; and an operational amplifier U3. DETAILED DESCRIPTION

[0032] 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.

[0033] IGBT and MOSFET (MOS tube) are voltage-controlled devices, and their driving methods are different from those of current-controlled devices such as triodes. However, in fact, they also require current (charge) during the switching process. Taking MOSFET as an example, there are parasitic capacitances Cgd, Cgs and Cds between its poles. The conduction condition of MOSFET 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. The parameter values ​​of these three parasitic capacitances 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.

[0034] The gate charging curve of MOSFET is as follows: Figure 1As shown in the figure, during the charging process of the gate of the MOSFET, Vgs increases with the increase of the 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 range, 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.

[0035] 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 2 As 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, while 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.

[0036] In order to solve the above problems, the first embodiment of the utility model provides a driving circuit. The driving 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.

[0037] Reference below Figure 3 The driving circuit 900 according to the embodiment of the present utility model is described as follows: Figure 3 As shown, the driving circuit 900 includes: a first driving module 1 , a voltage detection module 2 , a second driving module 3 and a control module 4 .

[0038] Among them, the first driving module 1 includes a driver chip 11 and a first driving branch 12, and the driver chip 11 is used to drive the first driving branch 12 to be turned on or off; the voltage detection module 2 is connected to the power device 800, and is used to detect the voltage value between the gate of the power device 800 and the source of the power device 800; the second driving module 3 includes a microprocessor 31 and at least one second driving branch 32, each second driving branch 32 is connected to the first driving branch 12 in parallel and then connected to the power device 800, the microprocessor 31 is connected to the voltage detection module 2, and the microprocessor 31 is used to drive the second driving branch 32 to be turned on or off; the control module 4 is connected to the driver chip 11 and the microprocessor 31; wherein, when it is determined that the voltage value is not within the Miller platform voltage range, the first driving branch 12 is turned on to drive the power device 800, and when it is determined that the voltage value is within the Miller platform voltage range, the first driving branch 12 and at least one second driving branch 32 are turned on at the same time to drive the power device 800.

[0039] Specifically, in order to solve the problem that the Miller platform period prolongs the switching time of the power device 800 and increases the loss, the present application adds a second driving module 3 on the basis of the first driving module 1, that is, at least one second driving branch 32 is added on the basis of the original first driving branch 12. Based on this, during the switching process of the power device 800, the voltage value between the gate of the power device 800 and the source of the power device 800 is detected by the voltage detection module 2 to obtain the Miller platform voltage range, so that the control module 4 drives and controls the first driving module 1 and the second driving module 3 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 driver chip 11 is controlled to drive the first driving branch 12 to turn on to drive the power device 800, and When it is determined that the voltage value is within the Miller platform voltage range, the driver chip 11 and the microprocessor 31 are controlled to drive the first drive branch 12 and at least one second drive branch 32 to be turned on at the same time to drive the power device 800. That is to say, at least one second drive branch 32 only works during the Miller platform period, and at least one second drive branch 32 will not affect the circuit operation in other time periods. Therefore, during the Miller platform period, the first drive branch 12 and at least one second drive branch 32 jointly provide a drive current for the gate of the power device 800, which can effectively accelerate the progress of the Miller platform period, shorten the duration of the Miller platform, and thereby reduce the switching time of the power device 800, thereby improving the system efficiency. In addition, the present application requires fewer components and has a low cost, and has no effect on the circuit function outside the Miller platform period.

[0040] According to the drive circuit of the utility model, at least one second drive branch 32 is added on the basis of the original first drive branch 12, so that when it is determined that the voltage value is within the Miller platform voltage range, the control module 4 controls the first drive branch 12 and at least one second drive branch 32 to be turned on at the same time through the driver chip 11 and the microprocessor 31, thereby increasing the drive current of the power device 800, 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 800, and improving the system efficiency.

[0041] In some embodiments, Figure 3 As shown, the driver chip 11 includes a PWM signal receiving terminal, a power supply terminal VCC2 and a driving connection terminal OUTH, and the control module 4 includes a PWM signal output terminal PH.

[0042] Among them, the power supply terminal VCC2 is suitable for connecting the driving power supply, and the power supply terminal VCC2 is the positive voltage of the high-voltage side driving power supply to power the driver chip 11. The driving connection terminal OUTH is connected to the input terminal of the first driving branch 12 and the input terminal of each second driving branch 32, and the driving connection terminal OUTH is the output terminal of the PWM signal after being processed by the driver chip 11; 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 4, that is, the PWM signal output terminal PH is the signal output terminal for controlling the power device 800 to be turned on or off. Based on this, the driver chip 11 can turn on or off the first driving branch 12 according to the PWM signal provided by the control module 4. For example, when the PWM signal is a PWM_ON signal, the driver chip 11 drives the loop where the first driving branch 12 is located to be turned on to provide a driving current for the power device 800, and the power device 800 starts the conduction process.

[0043] In some embodiments, Figure 3 As shown, the driver chip 11 further includes: a signal processing unit 111 and a switch unit 112 .

[0044] The signal processing unit 111 is connected to the PWM signal receiving end and is used to process the PWM signal; the first end of the switch unit 112 is connected to the power supply end VCC2, the second end of the switch unit 112 is connected to the drive connection end OUTH, and the control end of the switch unit 112 is connected to the signal processing unit 111. The switch unit 112 can be a MOS tube.

[0045] Specifically, the PWM signal emitted by the control module 4 enters the signal processing unit 111 from the PWM signal receiving end. The signal processing unit 111 provides isolation, amplification, direct-through interlocking and other processing for the received PWM signal. The PWM signal is processed by the signal processing unit 111 and output to the control end of the switch unit 112. Thus, the switch unit 112 is turned on or off based on the PWM signal of the control module 4, and then turns on or off the first drive branch 12, so as to control whether the power device 800 is turned on.

[0046] Exemplarily, when the power device 800 needs to be driven to turn on, the control module 4 sends a PWM_ON signal to the signal processing unit 111 of the driver chip 11. The PWM_ON signal is output to the control end of the switch unit 112 after being isolated, amplified, and directly interlocked by the signal processing unit 111, so as to turn on the switch unit 112, thereby causing the loop where the first drive branch 12 is located to be turned on, so as to provide a driving current for the power device 800, and the power device 800 starts the conduction process; and the shutdown process of the power device 800 is similar to the above-mentioned conduction process, which will not be described in detail here.

[0047] In some embodiments, Figure 3 As shown, the first driving branch 12 includes: a first resistor R1. 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 800, that is, the first resistor R1 is used as the driving resistor of the driver chip 11 to drive the switch of the power device 800. For example, when the PWM signal is a PWM_ON signal, the driver chip 11 drives the loop where the first driving branch 12 is located to be turned on, that is, the driving loop composed of the power supply terminal VCC2, the driving connection terminal OUTH and the first resistor R1 is turned on to provide a driving current for the power device 800, and the power device 800 starts the conduction process.

[0048] In some embodiments, Figure 3 As shown, each second driving branch 32 includes: a MOS transistor Q1, a second resistor R2, a third resistor R3 and a fourth resistor R4.

[0049] Among them, the source S 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 D of the MOS tube Q1, and the second end of the second resistor R2 is connected to the gate of the power device 800; the first end of the third resistor R3 is connected to the source S 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 G of the MOS tube Q1; the first end of the fourth resistor R4 is connected to the gate G of the MOS tube Q1, and the second end of the fourth resistor R4 serves as the control end of the second driving branch 32 for receiving the driving control signal about the MOS tube Q1.

[0050] 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 32 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 32 is located is turned on, so that the second drive branch 32 and the first drive branch 12 jointly provide current for the power device 800, 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 32 is located is disconnected, and only the first drive branch 12 provides current for the power device 800. 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 32.

[0051] In some embodiments, Figure 3 As shown, the second driving module 3 further includes: a comparison unit 33 and an inversion unit 34 .

[0052] Among them, the first end of the comparison unit 33 is connected to the microprocessor 31, and the second end of the comparison unit 33 is connected to the output end of the voltage detection module 2; the input end of the inverting unit 34 is connected to the third end of the comparison unit 33, and the output end of the inverting unit 34 is connected to the control end of each second driving branch 32. The inverting unit 34 inverts the level signal output by the comparison unit 33 to provide a driving signal for the MOS tube Q1. The inverting unit 34 can be an inverter.

[0053] Exemplarily, when the control module 4 determines that the voltage value is not within the Miller platform voltage range, the comparison unit 33 outputs a low-level signal and is converted into a high-level signal after being inverted by the inverting unit 34, and the high-level signal is transmitted to the control end of each second driving branch 32. Thus, each second driving branch 32 receives a high-level signal of the driving control signal of the MOS tube Q1. When the MOS tube Q1 is a PMOS tube, the MOS tube Q1 is controlled to be cut off, and the second driving branch 32 is disconnected, that is, only the first driving branch 12 provides current to the power device 800, and the second driving branch 32 is disconnected. 32 does not participate in the turn-on process of the power device 800; when the control module 4 determines that the voltage value is within the Miller platform voltage range, the comparison unit 33 outputs a high-level signal and is converted into a low-level signal after being reversed by the inverting unit 34, and the low-level signal is transmitted to the control end of each second drive branch 32, thereby, each second drive branch 32 receives the drive control signal of the MOS tube Q1 as a low-level signal, the second drive branch 32 is turned on, and together with the first drive branch 12, provides current for the power device 800, 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 800.

[0054] In some embodiments, Figure 3 and Figure 4 As shown, the microprocessor 31 includes an AD conversion terminal ADG, a first signal output port PWMH and a second signal output port PWML, and the comparison unit 33 includes: a first comparison subunit 331 and a second comparison subunit 332 .

[0055] Among them, the AD conversion terminal ADG is connected to the output terminal of the voltage detection module 2, and the microprocessor 31 is used to output the first voltage signal and the second voltage signal according to the voltage value; the same-direction input terminal of the first comparison subunit 331 is connected to the first signal output port PWMH to receive the first voltage signal, the reverse input terminal of the first comparison subunit 331 is connected to the output terminal of the voltage detection module 2, and the output terminal of the first comparison subunit 331 is connected to the input terminal of the inverting unit 34; the reverse input terminal of the second comparison subunit 332 is connected to the second signal output port PWML to receive the second voltage signal, the same-direction input terminal of the second comparison subunit 332 is connected to the output terminal of the voltage detection module 2, and the output terminal of the second comparison subunit 332 is connected to the output terminal of the first comparison subunit 331 and the input terminal of the inverting unit 34.

[0056] Specifically, the microprocessor 31 outputs a first voltage signal and a second voltage signal according to the voltage value. The first voltage signal and the second voltage signal can be PWM signals, that is, the microprocessor 31 obtains the upper limit voltage value and the lower limit voltage value of the Miller platform voltage range according to the voltage value, and then outputs the first voltage signal and the second voltage signal according to the Miller platform voltage range. The same-direction input end of the first comparison subunit 331 receives the first voltage signal, and the reverse input end of the first comparison subunit 331 receives the voltage value detected by the voltage detection module 2. The first comparison subunit 331 determines whether the voltage value is lower than the first voltage signal, that is, determines whether the voltage value is lower than the upper limit voltage value, and then outputs a level signal from the output end of the first comparison subunit 331 according to the judgment result. The same-direction input end of the second comparison subunit 332 receives the voltage value detected by the voltage detection module 2, and the second comparison subunit 332 receives the voltage value detected by the voltage detection module 2. The reverse input terminal of unit 332 receives the second voltage signal, and the output terminal of the second comparison subunit 332 outputs a high-level signal. The second comparison subunit 332 determines whether the voltage value is higher than the second voltage signal, that is, determines whether the voltage value is higher than the lower limit voltage value, and then outputs a level signal from the output terminal of the second comparison subunit 332 according to the judgment result. Finally, the level signal of the comparison unit 33 is determined by the output terminals of the first comparison subunit 331 and the second comparison subunit 332. That is to say, when the voltage value is within the Miller platform voltage range, the first comparison subunit 331 and the second comparison subunit 332 both output high-level signals, and the comparison unit 33 outputs a high-level signal. When the voltage value is not within the Miller platform voltage range, the level signals output by the first comparison subunit 331 and the second comparison subunit 332 are different, and the comparison unit 33 outputs a low-level signal.

[0057] Exemplarily, when the control module 4 determines that the voltage value is not within the Miller platform voltage range, the microprocessor 31 outputs the first voltage signal and the second voltage signal according to the voltage value, that is, the voltage average value of the first voltage signal output by the microprocessor 31 according to the voltage value is less than the average value of the second voltage signal, or the output first voltage signal is the same as the second voltage signal. For example, the first voltage signal and the second voltage signal can be 0, so that the judgment result of the voltage value and the first voltage signal and the second voltage signal does not meet the Miller platform voltage range, thereby ensuring that the comparison unit 33 outputs a low-level signal, and is converted into a high-level signal after being inverted by the inverting unit 34, and the high-level signal is transmitted to the control end of each second drive branch 32. As a result, each second drive branch 32 receives the drive control signal of the MOS tube Q1 as a high-level signal to control the MOS tube Q1 to be turned off, and then the second drive branch 32 is disconnected, that is, only the first drive branch 12 provides current to the power device 800, and the second drive branch 32 does not participate in the turn-on process of the power device 800.

[0058] When the control module 4 determines that the voltage value is within the Miller platform voltage range, the microprocessor 31 outputs a first voltage signal and a second voltage signal according to the voltage value, that is, the microprocessor 31 first obtains the upper limit voltage value and the lower limit voltage value of the Miller platform voltage range according to the voltage value, and then outputs the first voltage signal and the second voltage signal of the corresponding duty cycle according to the upper limit voltage value and the lower limit voltage value of the Miller platform voltage range, so that the average voltage value of the first voltage signal is equal to the upper limit voltage value of the Miller platform voltage range, and the average voltage value of the second voltage signal is equal to the lower limit voltage value of the Miller platform voltage range, and the first comparison subunit 331 determines that the voltage value is lower than the Miller platform voltage range. The upper limit voltage value, the second comparison subunit 332 determines that the voltage value is higher than the lower limit voltage value of the Miller platform voltage range, then the first comparison subunit 331 and the second comparison subunit 332 both output a high level, then the comparison unit 33 outputs a high level signal, which is converted into a low level signal after being reversed by the inverting unit 34, and the low level signal is transmitted to the control end of each second driving branch 32, thereby, each second driving branch 32 receives the driving control signal of the MOS tube Q1 as a low level signal, the second driving branch 32 is turned on, and together with the first driving branch 12, provides current to the power device 800, 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 opening of the power device 800.

[0059] In some embodiments, Figure 4 As shown, the first comparison subunit 331 includes: a first comparator U1, a fifth resistor R5, a sixth resistor R6 and a first capacitor C1.

[0060] Among them, the output end of the first comparator U1 is connected to the input end of the inverting unit 34, and the reverse input end of the first comparator U1 is connected to the output end of the voltage detection module 2; the first end of the fifth resistor R5 is connected to the output end of the first comparator U1 and the input end of the inverting unit 34, and the second end of the fifth resistor R5 is connected to the same-direction input end of the first comparator U1; the first end of the sixth resistor R6 is connected to the first signal output port PWMH, and the second end of the sixth resistor R6 is connected to the second end of the fifth resistor R5 and the same-direction input end of the first comparator U1; the first end of the first capacitor C1 is connected to the first end of the sixth resistor R6 and the first signal output port PWMH, and the second end of the first capacitor C1 is grounded GND2, GND2 is the high-voltage side signal ground, and the first capacitor C1 is a filter capacitor, so that the average voltage value of the first voltage signal after filtering by the first capacitor C1 reaches a stable state.

[0061] In some embodiments, Figure 4 As shown, the second comparison subunit 332 includes: a second comparator U2, a seventh resistor R7, an eighth resistor R8 and a second capacitor C2.

[0062] Among them, the output end of the second comparator U2 is connected to the output end of the first comparator U1 and the input end of the inverting unit 34, and the inverting input end of the second comparator U2 is connected to the second signal output port PWML; the first end of the seventh resistor R7 is connected to the same-direction input end of the second comparator U2, and the second end of the seventh resistor R7 is connected to the output end of the voltage detection module 2; the first end of the eighth resistor R8 is connected to the output end of the second comparator U2, and the second end of the eighth resistor R8 is connected to the first end of the seventh resistor R7 and the same-direction input end of the second comparator U2; the first end of the second capacitor C2 is connected to the inverting input end of the second comparator U2 and the second signal output port PWML, and the second end of the second capacitor C2 is grounded GND2. The second capacitor C2 is a filter capacitor, so that the average voltage value of the second voltage signal after filtering by the second capacitor C2 reaches a stable state.

[0063] Therefore, a hysteresis window comparator is formed by the first comparator U1, the fifth resistor R5 and the sixth resistor R6 of the first comparison subunit 331, and the second comparator U2, the seventh resistor R7 and the eighth resistor R8 of the second comparison subunit 332. Since the window comparator has a hysteresis function, it can effectively filter out signal interference and improve the reliability of the driving system.

[0064] Exemplarily, when the control module 4 determines that the voltage value is not within the Miller platform voltage range, the microprocessor 31 outputs the first voltage signal and the second voltage signal according to the voltage value, that is, the voltage average value of the first voltage signal output by the microprocessor 31 according to the voltage value is less than the average value of the second voltage signal, or the output first voltage signal is the same as the second voltage signal. For example, the first voltage signal and the second voltage signal can be 0, so that the first comparator U1 and the second comparator U2 determine that the voltage value does not meet the Miller platform voltage range, thereby ensuring that the comparison unit 33 outputs a low-level signal, and after the inverting unit 34 is inverted and converted into a high-level signal, and the driving control loop composed of the power supply terminal VCC2, the driving connection terminal OUTH, the MOS transistor Q1, the fourth resistor R4 and the inverter is cut off, that is, disconnected, then the second driving branch 32 is disconnected, and the driving loop composed of the power supply terminal VCC2, the driving connection terminal OUTH, the MOS transistor Q1 and the second resistor R2 is disconnected, that is, only the driving loop composed of the power supply terminal VCC2, the driving connection terminal OUTH and the first resistor R1, that is, the first driving branch 12 provides current for the power device 800, and the second driving branch 32 does not participate in the turn-on process of the power device 800.

[0065] When the control module 4 determines that the voltage value is within the Miller platform voltage range, the microprocessor 31 outputs the first voltage signal and the second voltage signal according to the voltage value, that is, the microprocessor 31 first obtains the upper limit voltage value and the lower limit voltage value of the Miller platform voltage range according to the voltage value, and then outputs the first voltage signal and the second voltage signal of the corresponding duty cycle according to the upper limit voltage value and the lower limit voltage value of the Miller platform voltage range, so that the average voltage value of the first voltage signal is equal to the upper limit voltage value of the Miller platform voltage range, and reaches a stable state after filtering by the first capacitor C1, that is, the upper limit reference voltage VrefH of the Miller platform voltage range is obtained, and the average voltage value of the second voltage signal is equal to the lower limit voltage value of the Miller platform voltage range, and reaches a stable state after filtering by the second capacitor C2, that is, the lower limit reference voltage VrefL of the Miller platform voltage range is obtained, VrefL and VrefH are also threshold voltages of the window comparator, and the first comparator The comparator U1 determines that the voltage value is lower than the upper limit reference voltage VrefH of the Miller platform voltage range, and the second comparator U2 determines that the voltage value is higher than the lower limit reference voltage of the Miller platform voltage range, then the first comparator U1 and the second comparator U2 both output high level, then the comparison unit 33 outputs a high level signal, which is converted into a low level signal after being inverted by the inverting unit 34, and the drive control loop composed of the power supply terminal VCC2, the drive connection terminal OUTH, the MOS tube Q1, the fourth resistor R4 and the inverter is turned on, then the second drive branch 32 is turned on, that is, the drive 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, and together with the drive loop composed of the power supply terminal VCC2, the drive connection terminal OUTH and the first resistor R1, that is, the first drive branch 12, provides current to the power device 800, 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 opening of the power device 800.

[0066] In addition, the lower limit reference voltage VrefL should be set first and then the upper limit reference voltage VrefH should be set after it reaches stability, so as to ensure that the time period during which the window comparator output is high level will not exceed the interval range during which the window comparator output is high level after the reference voltage stabilizes, that is, the Miller platform voltage range, to ensure that there is no impact on the circuit operation state outside the Miller platform voltage range.

[0067] In some embodiments, Figure 4 As shown, the voltage detection module 2 includes: a detection unit 21 and an amplification unit 22 .

[0068] Among them, the first end of the detection unit 21 is connected to the gate of the power device 800, and the second end of the detection unit 21 is connected to the source of the power device 800; the output end of the amplification unit 22 is connected to the AD conversion end ADG, the first input end of the amplification unit 22 is connected to the first end of the detection unit 21, and the second input end of the amplification unit 22 is connected to the second end of the detection unit 21.

[0069] In some embodiments, Figure 4 As shown, the amplifying unit 22 includes: an operational amplifier U3, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11 and a twelfth resistor R12.

[0070] Among them, the output end of the operational amplifier U3 is connected to the AD conversion end ADG; the first end of the ninth resistor R9 is connected to the first end of the detection unit 21, and the second end of the ninth resistor R9 is connected to the first input end of the operational amplifier U3; the first end of the tenth resistor R10 is connected to the second end of the detection unit 21, and the second end of the tenth resistor R10 is connected to the second input end of the operational amplifier U3; the first end of the eleventh resistor R11 is connected to the second end of the ninth resistor R9 and the first input end of the operational amplifier U3, and the second end of the eleventh resistor R11 is grounded; the first end of the twelfth resistor R12 is connected to the second end of the tenth resistor R10 and the second input end of the operational amplifier U3, and the second end of the twelfth resistor R12 is connected to the output end of the operational amplifier U3 and the AD conversion end ADG.

[0071] Specifically, during the conduction process of the power device 800, the differential amplifier composed of the operational amplifier U3, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11 and the twelfth resistor R12 continuously processes the voltage across the detection unit 21 according to the corresponding proportion, and sends it to the AD conversion terminal ADG of the microprocessor 31. The microprocessor 31 calculates the voltage change rate dv / dt of the voltage across the detection unit 21. Because the voltage change rate of the voltage across the detection unit 21 during the Miller platform is much smaller than that in other time periods, the upper and lower limit voltage values ​​of the Miller platform voltage range can be obtained. In addition, after several detection cycles, more accurate upper and lower limit voltage values ​​of the Miller platform voltage range can be obtained.

[0072] In some embodiments, Figure 4 As shown, the detection unit 21 includes: a detection resistor Rge, wherein a first end of the detection resistor Rge is connected to the gate of the power device 800, and a second end of the detection resistor Rge is connected to the source of the power device 800, that is, the detection unit 21 detects the voltage across the detection resistor Rge.

[0073] Exemplarily, when the power device 800 is an IGBT, the voltage detection module detects the voltage value between the gate and the emitter of the IGBT, and the detection resistor Rge is located between the gate of the IGBT and the emitter of the IGBT. During the conduction process of the power device 800, the differential amplifier composed of the operational amplifier U3, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11 and the twelfth resistor R12 continuously processes the voltage between the gate and the emitter of the IGBT according to the corresponding proportion, that is, the voltage Vge across the detection resistor Rge, and sends it to the AD conversion terminal ADG of the microprocessor 31. The microprocessor 31 calculates the voltage change rate dv / dt of Vge. Because the voltage change rate of the voltage across the detection unit 21 during the Miller platform is much smaller than that in other time periods, the upper and lower limit voltage values ​​of the Miller platform voltage range can be obtained. In addition, it should be noted that when the power device is a MOS tube, the voltage detection module detects the voltage value between the gate of the MOS tube and the source of the MOS tube.

[0074] In the embodiment, the control module 4 is a microprocessor of the motor drive system, and the microprocessor 31 is a high-voltage side single-chip microcomputer, such as Figure 3 As shown, the control module 4 communicates with the microprocessor 31 through the communication port PX.

[0075] In the embodiment, when the working condition of the control module 4 changes, such as the IGBT temperature rises or falls, the voltage value of the Miller platform may change. Therefore, the threshold voltages VrefH and VrefL of the window comparator can be appropriately adjusted according to the upper and lower limit voltage values ​​of the Miller platform voltage range detected by the AD conversion terminal ADG of the microprocessor 31, so that the drive circuit can better serve the Miller platform period.

[0076] The second aspect of the present utility model provides a drive system 1000, such as Figure 5 As shown, the driving system 1000 includes: a power device 800 and the driving circuit 900 of the above embodiment.

[0077] The driving circuit 900 is used to drive the power device 800 to turn on or off. The power device can be an IGBT or a MOS tube, etc., which is not limited.

[0078] According to the drive system of the present invention, through the drive circuit of the above embodiment, the process of the Miller platform period can be effectively accelerated, the duration of the Miller platform can be shortened, and the switching time of the power device 800 can be reduced, thereby improving the system efficiency.

[0079] 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.

[0080] 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 first driving module, the first driving module comprising a driver chip and a first driving branch, the driver chip is used to drive the first driving branch to be turned on or off; A voltage detection module, the voltage detection module is suitable for being connected to a 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 second driving module, the second driving module includes a microprocessor and at least one second driving branch, each second driving branch is connected to the first driving branch in parallel and then connected to the power device, the microprocessor is connected to the voltage detection module, and the microprocessor is used to drive the second driving branch to be turned on or off; A control module, the control module is connected to the driver chip and the microprocessor; When it is determined that the voltage value is not within the Miller platform voltage range, the first driving branch is turned on to drive the power device, and when it is determined that the voltage value is within the Miller platform voltage range, the first driving branch and at least one second driving branch are turned on at the same time to drive the power device.

2. The driving circuit according to claim 1, characterized in that: The driver chip includes a PWM signal receiving end, a power supply end and a driving connection end, wherein 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, 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 serves as a control end of the second driving branch to receive a driving control signal about the MOS tube.

6. The driving circuit according to claim 1 or 5, characterized in that: The second driving module further includes: A comparison unit, wherein a first end of the comparison unit is connected to the microprocessor, and a second end of the comparison unit is connected to an output end of the voltage detection module; An inverting unit, wherein an input end of the inverting unit is connected to the third end of the comparing unit, and an output end of the inverting unit is connected to the control end of each second driving branch.

7. The driving circuit according to claim 6, characterized in that: The microprocessor comprises an AD conversion terminal, a first signal output port and a second signal output port, the AD conversion terminal is connected to the output terminal of the voltage detection module, and the microprocessor is used to output a first voltage signal and a second voltage signal according to the voltage value; The comparison unit comprises: a first comparing subunit, wherein a non-inverting input terminal of the first comparing subunit is connected to the first signal output port to receive the first voltage signal, a reverse input terminal of the first comparing subunit is connected to the output terminal of the voltage detection module, and an output terminal of the first comparing subunit is connected to the input terminal of the inverting unit; A second comparing subunit, wherein the inverting input terminal of the second comparing subunit is connected to the second signal output port to receive the second voltage signal, the non-inverting input terminal of the second comparing subunit is connected to the output terminal of the voltage detection module, and the output terminal of the second comparing subunit is connected to the output terminal of the first comparing subunit and the input terminal of the inverting unit.

8. The driving circuit according to claim 7, characterized in that: The first comparison subunit comprises: A first comparator, wherein an output terminal of the first comparator is connected to an input terminal of the inverting unit, and a reverse input terminal of the first comparator is connected to an output terminal of the voltage detection module; a fifth resistor, wherein a first end of the fifth resistor is connected to the output end of the first comparator and the input end of the inverting unit, and a second end of the fifth resistor is connected to the non-inverting input end of the first comparator; a sixth resistor, wherein a first end of the sixth resistor is connected to the first signal output port, and a second end of the sixth resistor is connected to the second end of the fifth resistor and the non-inverting input end of the first comparator; A first capacitor, wherein a first end of the first capacitor is connected to the first end of the sixth resistor and the first signal output port, and a second end of the first capacitor is grounded.

9. The driving circuit according to claim 8, characterized in that: The second comparison subunit comprises: a second comparator, wherein an output terminal of the second comparator is connected to an output terminal of the first comparator and an input terminal of the inverting unit, and an inverting input terminal of the second comparator is connected to the second signal output port; a seventh resistor, wherein a first end of the seventh resistor is connected to the non-inverting input end of the second comparator, and a second end of the seventh resistor is connected to the output end of the voltage detection module; an eighth resistor, wherein a first end of the eighth resistor is connected to the output end of the second comparator, and a second end of the eighth resistor is connected to the first end of the seventh resistor and the non-inverting input end of the second comparator; A second capacitor, wherein a first end of the second capacitor is connected to the inverting input end of the second comparator and the second signal output port, and a second end of the second capacitor is grounded.

10. The driving circuit according to any one of claims 7 to 9, characterized in that: The voltage detection module comprises: A detection unit, wherein a first end of the detection unit is connected to a gate of the power device, and a second end of the detection unit is connected to a source of the power device; an amplifying unit, wherein the output end of the amplifying unit is connected to the AD conversion end, the first input end of the amplifying unit is connected to the first end of the detecting unit, and the second input end of the amplifying unit is connected to the second end of the detecting unit.

11. The driving circuit according to claim 10, characterized in that: The amplification unit comprises: An operational amplifier, wherein the output terminal of the operational amplifier is connected to the AD conversion terminal; a ninth resistor, wherein a first end of the ninth resistor is connected to the first end of the detection unit, and a second end of the ninth resistor is connected to the first input end of the operational amplifier; a tenth resistor, wherein a first end of the tenth resistor is connected to the second end of the detection unit, and a second end of the tenth resistor is connected to the second input end of the operational amplifier; an eleventh resistor, a first end of the eleventh resistor being connected to the second end of the ninth resistor and the first input end of the operational amplifier, and a second end of the eleventh resistor being grounded; A twelfth resistor, wherein a first end of the twelfth resistor is connected to the second end of the tenth resistor and the second input end of the operational amplifier, and a second end of the twelfth resistor is connected to the output end of the operational amplifier and the AD conversion end.

12. The driving circuit according to claim 10, 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.

13. A drive system, characterized in that: include: Power devices; The drive circuit according to any one of claims 1 to 12, wherein the drive circuit is used to drive the power device to turn on or off.

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