A driving method, a driving circuit of an amplification module and an electronic device

Abstract

The application provides a driving method, a driving circuit of an amplification module and electronic equipment, and the method comprises the following steps: when the power tube is turned on: outputting a first conduction current to the gate of the power tube; after the gate-source voltage of the power tube rises to a threshold voltage, reducing the first conduction current to a second conduction current, so as to reduce the reverse recovery current of the corresponding body diode of the power tube; after the gate-source voltage of the power tube rises from the threshold voltage to a Miller voltage, increasing the second conduction current to a third conduction current until the power tube is completely turned on; when the power tube is turned off: outputting a first turn-off current to the gate of the power tube until the power tube is completely turned off. In the process of turning on the power tube, after the gate-source voltage of the power tube rises to the threshold voltage, the first conduction current is reduced to the second conduction current, so as to reduce the reverse recovery current of the corresponding body diode of the power tube, avoid the overshoot of the power tube in the process of turning on, and improve the turn-on safety of the power tube.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of amplifiers, in particular to a driving method, a driving circuit of an amplification module and an electronic device. BACKGROUND

[0002] The classical closed-loop class-D amplifier modulates the input audio signal or the signal inputted through the DAC by an integrator, inputs the modulated signal and a triangular wave carrier into a comparator for comparison. The comparator outputs a square wave signal with different duty cycles to a driving circuit according to the comparison result. The driving circuit outputs a corresponding driving signal to control the conduction and cutoff of the output stage power tube after receiving the square wave signal, so as to realize the amplification of the square wave signal. Finally, a low-pass filter restores the amplified square wave signal to an audio sine signal, thereby realizing the amplification of the input audio signal.

[0003] Then, the conventional driving circuit has the risk of power tube breakdown and burnout due to overshoot when turning on the output stage power tube, thereby reducing the safety of the turned-on power tube.

[0004] Therefore, it has become a technical problem in the industry to provide a driving method for improving the safety of power conduction. SUMMARY

[0005] The technical problem solved by the present application is to provide a driving method, a driving circuit of an amplification module and an electronic device, which solves the safety problem of the power tube during conduction.

[0006] To solve the above technical problem, the first aspect of the technical solution of the present application provides a driving method for driving a power tube, comprising:

[0007] When turning on the power tube:

[0008] outputting a first conduction current to the gate of the power tube;

[0009] after the gate-source voltage of the power tube rises to a threshold voltage, reducing the first conduction current to a second conduction current to reduce the reverse recovery current of the corresponding body diode of the power tube;

[0010] after the gate-source voltage of the power tube rises from the threshold voltage to a Miller voltage, increasing the second conduction current to a third conduction current until the power tube is completely turned on;

[0011] When turning off the power tube:

[0012] the gate of the power tube outputs a first turn-off current until the power tube is completely turned off.

[0013] Optionally, the first conduction current is greater than the third conduction current.

[0014] Optionally, after the second conduction current is increased to the third conduction current, the method further comprises:

[0015] After the drain-source voltage of the power tube drops to zero, the third conduction current is increased to a fourth conduction current.

[0016] Optionally, the method further comprises:

[0017] The gate of the power tube outputs a second turn-off current;

[0018] After the gate-source voltage of the power tube drops to the Miller voltage, the second turn-off current is reduced to a third turn-off current;

[0019] After the gate-source voltage of the power tube drops to the threshold voltage, the third turn-off current is increased to a fourth turn-off current until the power tube is completely turned off.

[0020] Correspondingly, a second aspect of the technical solution of the present application provides another driving method for driving an amplification module, wherein the amplification module comprises a first power tube and a second power tube, the drain of the first power tube is connected to a power supply voltage, the source of the first power tube is connected to the drain of the second power tube and serves as an output terminal of the amplification module, and the source of the second power tube is connected to a ground terminal; the method comprises:

[0021] When the second power tube is turned off, a second gate-source voltage of the second power tube is detected;

[0022] When the second gate-source voltage of the second power tube is less than or equal to a threshold voltage, the first power tube is turned on;

[0023] When the first power tube is turned off, a first gate-source voltage of the first power tube is detected;

[0024] When the first gate-source voltage of the first power tube is less than or equal to the threshold voltage, the second power tube is turned on;

[0025] The turning on of the first power tube and the turning on of the second power tube each comprises:

[0026] A first conduction current is output to the gate of the power tube to be driven;

[0027] After the gate-source voltage of the power tube to be driven rises to the threshold voltage, the first conduction current is reduced to a second conduction current to reduce the reverse recovery current of the corresponding body diode of the power tube to be driven;

[0028] After the gate-source voltage of the power tube to be driven rises from the threshold voltage to the Miller voltage, the second conduction current is increased to a third conduction current until the power tube to be driven is fully turned on.

[0029] Optionally, the first conduction current is greater than the third conduction current.

[0030] Optionally, after the second conduction current is increased to the third conduction current, the method further comprises:

[0031] After the drain-source voltage of the power tube drops to zero, the third conduction current is increased to a fourth conduction current.

[0032] Optionally, the first power tube and the second power tube each comprise an NMOS tube.

[0033] Correspondingly, a third aspect of the technical scheme of the present application provides a driving circuit of an amplification module, the amplification module comprising a first power tube and a second power tube, the drain of the first power tube being connected to a power supply voltage, the source of the first power tube being connected to the drain of the second power tube and serving as an output terminal of the amplification module, the source of the second power tube being connected to a ground terminal, the driving circuit comprising:

[0034] a first driving module, the first driving module being configured to turn on or turn off the first power tube according to a first control signal and according to the driving method provided in the first aspect of the technical scheme of the present application;

[0035] a second driving module, the second driving module being configured to turn on or turn off the second power tube according to a second control signal and according to the driving method provided in the first aspect of the technical scheme of the present application;

[0036] a bootstrap module, the bootstrap module being configured to boost the output voltage of the amplification module and use the boosted output voltage as the power supply voltage of the first driving module;

[0037] a logic control module and a level shift module, the logic control module being configured to receive an externally input control square wave and output a first control signal to the level shift module according to the control square wave, the level shift module being configured to perform level conversion on the first control signal and output a second control signal to the first driving module, and the logic control module being further configured to output a third control signal to the second driving module according to the control square wave;

[0038] a threshold detection module, the threshold detection module being configured to detect the first gate-source voltage of the first power tube and output the first gate-source voltage to the logic control module, and the threshold detection module being further configured to detect the second gate-source voltage of the second power tube and output the second gate-source voltage to the logic control module;

[0039] The logic control module is further configured to output a second control signal to control the second drive module to turn on the second power tube according to the first gate-source voltage being less than a threshold voltage when the first power tube is turned off, and output a first control signal to control the first drive module to turn on the first power tube according to the second gate-source voltage being less than a threshold voltage when the second power tube is turned off.

[0040] Correspondingly, the fourth aspect of the technical scheme of the present application provides an electronic device, which comprises the drive circuit of the amplification module provided by the third aspect of the technical scheme of the present application.

[0041] Compared with the prior art, the technical scheme of the embodiment of the present application has the following beneficial effects:

[0042] In the driving method provided by the first aspect of the technical scheme of the present application, after the gate-source voltage of the power tube rises to the threshold voltage, the first on-current is reduced to the second on-current, so as to reduce the reverse recovery current of the body diode corresponding to the power tube, and avoid the overshoot of the power tube in the on process, thereby improving the on safety of the power tube.

[0043] Further, by setting the first on-current to be greater than the third on-current, and increasing the third on-current to the fourth on-current after the drain-source voltage of the power tube drops to zero, the speed of the power tube in different stages of the on process is accelerated, thereby improving the on efficiency of the power tube on the basis of ensuring the on safety of the power tube. Meanwhile, in the Miller plateau stage of the on of the power tube, the on-current is reduced to avoid generating an excessively large peak voltage.

[0044] Further, by setting the gate of the power tube to output the second off-current, so as to make the gate-source voltage of the power tube drop to the Miller voltage, and by setting the gate of the power tube to output the fourth off-current after the gate-source voltage of the power tube drops to the threshold voltage, until the power tube is completely turned off. Since the second off-current and the fourth off-current are both greater than the third off-current, the speed of the power tube in different stages of the off process is accelerated, thereby improving the off efficiency of the power tube. Meanwhile, in the Miller plateau stage and the Miller plateau to the threshold voltage stage of the off of the power tube, the off-current is reduced to avoid generating an excessively large peak voltage and peak current.

[0045] The second aspect of the technical scheme of the present application provides the driving method. When the first power tube is turned off, the first gate-source voltage of the first power tube is detected. When the first gate-source voltage is less than or equal to the threshold voltage, the second power tube is turned on. When the second power tube is turned off, the second gate-source voltage of the second power tube is detected. When the second gate-source voltage is less than or equal to the threshold voltage, the first power tube is turned on. Through the above technical means, the adaptive control of the dead time of the first power tube and the second power tube is realized. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a waveform diagram of different parameters of the power tube in an on embodiment;

[0047] Figure 2 is a flow of the driving method provided by the technical scheme of the present application Figure 1 ;

[0048] Figure 3 is a waveform diagram of each parameter of the power tube turned on by the driving method provided by the technical scheme of the present application;

[0049] Figure 4 is a circuit structure diagram of the driving circuit provided by the embodiment of the present application Figure 1 ;

[0050] Figure 5 is a turn-on waveform diagram of the driving circuit provided by the embodiment of the present application;

[0051] Figure 6 is a flow of the driving method provided by the technical scheme of the present application Figure 2 ;

[0052] Figure 7 is a waveform diagram of each parameter of the power tube turned off by the driving method provided by the technical scheme of the present application;

[0053] Figure 8 is a circuit structure diagram of the driving circuit provided by the embodiment of the present application Figure 2 ;

[0054] Figure 9 is a turn-off waveform diagram of the driving circuit provided by the embodiment of the present application;

[0055] Figure 10 is a circuit structure diagram of the driving circuit of the amplification module provided by the technical scheme of the present application. DETAILED DESCRIPTION

[0056] As described in the background, the prior art has the risk of power tube being burned out due to overvoltage when the power tube is turned on, thereby reducing the safety of turning on the power tube.

[0057] The problems of the prior art in turning on the power tube are explained as follows:

[0058] Before explaining the problems of the prior art in turning on the power tube, the different stages of the power tube in the process of turning on are explained as follows:

[0059] Among them, Figure 1 is the waveform diagram of different parameters of the power tube in an embodiment of turning on.

[0060] Please refer to Figure 1 , the first stage: when the driving circuit outputs the turn-on current acting on the gate of the power tube, the gate-source voltage of the power tube rises from zero to the threshold voltage. The threshold voltage is the turn-on threshold voltage of the power tube, which is related to the size and type of the power tube and is not limited here. In this stage, the drain-source voltage and the drain current of the power tube are both zero.

[0061] The second stage: the gate-source voltage of the power tube rises from the threshold voltage to the Miller voltage. Since the gate-source voltage of the power tube rises to the threshold voltage, the power tube can start to carry current, so the drain current of the power tube rises from zero to the maximum current in this stage. The drain-source voltage of the power tube is still zero.

[0062] The third stage: the gate-source voltage of the power tube is maintained at the Miller voltage, so this stage is also called the Miller platform stage. In this stage, the power tube is gradually turned on, and the drain-source voltage of the power tube gradually decreases to zero.

[0063] The fourth stage: the gate-source voltage of the power tube rises from the Miller voltage to the maximum driving voltage, and the power tube is completely turned on.

[0064] Because there is a parasitic structure, i.e. a body diode, between the source and the drain of the power tube, when the power tube is turned on, the corresponding body diode of the power tube is turned off, thereby generating a reverse recovery current flowing from the negative electrode to the positive electrode, and then gradually recovering to zero. But in the second stage of turning on, the turn-on current of the power tube flows into the negative electrode of the body diode from the drain of the power tube, thereby increasing the reverse recovery current of the body diode. Because the prior art usually uses constant current to turn on the power tube, the reverse recovery current of the body diode is greatly increased, which leads to the overvoltage from the drain to the source of the power tube, thereby greatly increasing the risk of the power tube being burned out.

[0065] Therefore, the technical scheme of the present application provides a new driving method for driving the power tube.

[0066] wherein, Figure 2 is the flow of the driving method provided by the technical scheme of the present application Figure 1 . Figure 3 is the waveform diagram of each parameter of the power tube turned on by the driving method provided by the technical scheme of the present application.

[0067] Please refer to Figure 2 and Figure 3 , the technical scheme of the present application provides a driving method for driving a power tube, which comprises the following steps:

[0068] S11: determine whether to turn on or turn off the power tube; if it is turned on, jump to S12; if it is turned off, jump to S15.

[0069] S12: output a first turn-on current IG1st to the gate of the power tube.

[0070] S13: after the gate-source voltage of the power tube rises to the threshold voltage Vth, the first turn-on current IG1st is reduced to the second turn-on current IG2nd to reduce the reverse recovery current of the corresponding body diode of the power tube.

[0071] S14: after the gate-source voltage of the power tube rises from the threshold voltage Vth to the Miller voltage Vmiller, the second turn-on current IG2nd is increased to the third turn-on current IG3rd until the power tube is completely turned on.

[0072] S15: the gate of the power tube outputs a first turn-off current until the power tube is completely turned off.

[0073] Through the above technical means, the technical scheme of the present application greatly improves the safety of the power tube in the conduction process. The specific reasons are as follows:

[0074] As can be known from the above description, in the second stage of the conduction of the power tube, the turn-on current acting on the gate of the power tube flows into the negative electrode of the body diode through the drain of the power tube, thereby increasing the reverse recovery current of the body diode. Therefore, the technical scheme of the present application specifically reduces the first turn-on current IG1st to the second turn-on current IG2nd in the second stage of the conduction of the power tube to reduce the current flowing into the body diode in this stage, thereby reducing the reverse recovery current of the body diode, and further avoiding the risk of burning out and breakdown of the power tube due to overshoot, greatly improving the safety of the power tube in the conduction process.

[0075] It should be noted that the specific size of the second conduction current IG2nd can be selected according to the specific size, type and withstand voltage capacity of the power tube, which is not limited herein. However, regardless of the specific size, type and withstand voltage capacity of the power tube, the second conduction current IG2nd is smaller than the constant current value for driving the same type of power tube in the prior art.

[0076] To make the above-mentioned purposes, features and benefits of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0077] As a specific embodiment, after the second conduction current IG2nd is increased to the third conduction current IG3rd in S14, the method further comprises:

[0078] After the drain-source voltage of the power tube decreases to zero, the third conduction current IG3rd is increased to a fourth conduction current. The first conduction current IG1st is set to be greater than the third conduction current IG3rd, and the third conduction current IG3rd is approximately equal to the constant current value for turning on the same type of power tube in the prior art.

[0079] The embodiment has the beneficial effect that by setting the first conduction current IG1st and the fourth conduction current to be greater than the third conduction current IG3rd, the rate of the power tube in the first stage and the fourth stage of conduction is accelerated, thereby improving the conduction efficiency of the power tube on the basis of ensuring the safety of the power tube conduction.

[0080] It should be noted that the reason for not increasing the third conduction current IG3rd is that during the third stage of power tube conduction, i.e. the Miller plateau period, the drain-source voltage of the power tube will decrease to zero. If the conduction current in this stage is too large, it will shorten the Miller plateau period, causing the drain-source voltage of the power tube to decrease too quickly and generate a large peak voltage, thereby greatly increasing the risk of breakdown of the power tube.

[0081] As a supplement, the first conduction current IG1st can be set to 2-3 times the constant current value for turning on the same type of power tube in the prior art. Of course, the first conduction current IG1st can also be set to different sizes according to requirements. The fourth conduction current can also be set to 2-3 times the constant current value for turning on the same type of power tube in the prior art. Of course, the fourth conduction current can also be set to different sizes according to requirements. However, the first conduction current IG1st and the fourth conduction current are both greater than the constant current value for turning on the same type of power tube in the prior art.

[0082] Figure 4 is a circuit structure schematic of the driving circuit provided by the embodiment of the present application Figure 1 . Figure 5is a conduction waveform diagram of the driving circuit provided by the embodiment of the present application.

[0083] Before the working process of the driving method provided by the embodiment of the present application for turning on the power tube is described, the driving circuit for driving the power tube to turn on and the control method thereof are exemplified as follows:

[0084] Please refer to Figure 3 , Figure 4 and Figure 5 , the driving circuit for driving the power tube to turn on comprises a first PMOS tube M1, a second PMOS tube M2, a third PMOS tube M3 and a fourth PMOS tube M4; the source of the first PMOS tube M1, the source of the second PMOS tube M2, the source of the third PMOS tube M3 and the source of the fourth PMOS tube M4 are all connected to a power supply voltage; the drain of the first PMOS tube M1, the drain of the second PMOS tube M2, the drain of the third PMOS tube M3 and the drain of the fourth PMOS tube M4 are all connected to the gate of the power tube.

[0085] In the power tube conduction diagram, the first PMOS tube M1 and the second PMOS tube M2 are both turned on, and the driving circuit outputs the first conduction current IG1st.

[0086] In the second stage of the power tube conduction, the first PMOS tube M1 is turned off, and only the second PMOS tube M2 is turned on, and the driving circuit outputs the second conduction current IG2nd.

[0087] In the third stage of the power tube conduction, the third PMOS tube M3 is also turned on, and the driving circuit outputs the third conduction current IG3rd.

[0088] In the fourth stage of the power tube conduction, the fourth PMOS tube M4 is also turned on, and the driving circuit outputs the fourth conduction current.

[0089] The following takes the embodiment shown in Figure 4 and Figure 5 as an example to describe the working process of the driving method provided by the embodiment of the present application for turning on the power tube:

[0090] Please refer to Figure 2 , Figure 3 , Figure 4 and Figure 5 , the first stage of the power tube conduction: the first PMOS tube M1 and the second PMOS tube M2 are both turned on, and the driving circuit outputs the first conduction current IGlst to the gate of the power tube. The gate-source voltage of the power tube rises from zero to the threshold voltage Vth.

[0091] The second stage of power transistor turn-on: The first PMOS transistor M1 is turned off, and only the second PMOS transistor M2 is turned on. The output current of the drive circuit decreases to the second turn-on current IG2nd and is output to the gate of the power transistor. The gate-source voltage of the power transistor rises from the threshold voltage Vth to the Miller voltage Vmiller. The power transistor begins to carry current, and its drain-source current rises from zero to its peak value, and then decreases from the peak value to a constant maximum value.

[0092] The third stage of power transistor conduction: The third PMOS transistor M3 is also turned on, the output current of the drive circuit increases to the third conduction current IG3rd, and is output to the gate of the power transistor. The gate-source voltage of the power transistor stabilizes at the Miller voltage Vmiller. The drain-source voltage of the power transistor decreases from a constant value to zero.

[0093] The fourth stage of power transistor conduction: The fourth PMOS transistor M4 is also turned on, the output current of the drive circuit increases to the fourth conduction current, and is output to the gate of the power transistor. The gate-source voltage of the power transistor rises from the Miller voltage Vmiller to a constant maximum value, and the power transistor is fully turned on.

[0094] Figure 6 This is the flow chart of the driving method provided by the technical solution of the present invention. Figure 2 . Figure 7 The waveform diagram shows the parameters of the power transistor being turned off using the driving method provided by the technical solution of this invention.

[0095] Please refer to Figure 6 and Figure 7 In one specific implementation, the method for turning off the power transistor, in addition to step S15, also includes the following steps:

[0096] S161: The gate of the power transistor outputs a second turn-off current IG2.

[0097] S162: After the gate-source voltage of the power transistor drops to the Miller voltage Vmiller, the second turn-off current IG2 is reduced to the third turn-off current IG3.

[0098] S163: After the gate-source voltage of the power transistor drops to the threshold voltage Vth, the third turn-off current IG3 is increased to the fourth turn-off current IG4 until the power transistor is completely turned off.

[0099] It should be noted that the third turn-off current IG3 and the first turn-off current can be set as the same current. Of course, the third turn-off current IG3 and the first turn-off current can also be set as different. But the second turn-off current IG2 and the fourth turn-off current IG4 are both greater than the first turn-off current, and the first turn-off current is set as the constant current value of the prior art for turning off the same power tube.

[0100] The embodiment has the beneficial effect that, since the second turn-off current IG2 and the fourth turn-off current IG4 are both greater than the third turn-off current IG3, the speed of the power tube in different stages of the turn-off process is accelerated, thereby improving the turn-off efficiency of the power tube.

[0101] It should be noted that the reason for not increasing the third turn-off current IG3 is similar to the reason for not increasing the third turn-on current IG3rd: during the Miller plateau of the power tube turn-off, the drain-source voltage of the power tube will increase from zero to the maximum value, and if the turn-off current in this stage is too large, the drain-source voltage of the power tube will increase too fast and generate a large peak voltage, thereby greatly increasing the risk of breakdown of the power tube. During the period when the gate-source voltage of the power tube decreases from the Miller voltage Vmiller to the threshold voltage Vth, the drain current of the power tube will decrease from the maximum value to zero, and if the turn-off current in this stage is too large, the drain current of the power tube will decrease too fast and generate a large peak current, thereby greatly increasing the risk of breakdown of the power tube.

[0102] As a supplement, the second turn-off current IG2 can be set as 2-3 times the constant current value of the prior art for turning off the same power tube. Of course, the second turn-off current IG2 can also be set as different sizes according to the needs. The fourth turn-off current IG4 can also be set as 2-3 times the constant current value of the prior art for turning off the same power tube. Of course, the fourth turn-off current IG4 can also be set as different sizes according to the needs. But the second turn-off current IG2 and the fourth turn-off current IG4 are both greater than the constant current value of the prior art for turning off the same power tube.

[0103] Figure 8 is a circuit structure schematic of the driving circuit provided by the embodiment of the application Figure 2 . Figure 9 is a turn-off waveform diagram of the driving circuit provided by the embodiment of the application.

[0104] Before the working process of the driving method provided by the embodiment of the application for turning off the power tube is described, the driving circuit for driving the power tube to turn off and the control method thereof are exemplified:

[0105] Please refer to Figure 8 and Figure 9The driving circuit for driving the power tube to be off includes a first NMOS tube M5, a second NMOS tube M6, a third NMOS tube M7 and a fourth NMOS tube M8; the source of the first NMOS tube M5, the source of the second NMOS tube M6, the source of the third NMOS tube M7 and the source of the fourth NMOS tube M8 are all connected to a ground terminal; the drain of the first NMOS tube M5, the drain of the second NMOS tube M6, the drain of the third NMOS tube M7 and the drain of the fourth NMOS tube M8 are all connected to the gate of the power tube.

[0106] In the first stage of the power tube being off, the first NMOS tube M5 and the second NMOS tube M6 are both turned on, and the driving circuit controls the gate of the power tube to output a second off current IG2.

[0107] In the second stage of the power tube being off, the second NMOS tube M6 is turned off, and the third NMOS tube M7 is also turned on, and the driving circuit controls the gate of the power tube to output a third off current IG3.

[0108] In the third stage of the power tube being off, the fourth NMOS tube M8 is also turned on, and the driving circuit controls the gate of the power tube to output a fourth off current IG4.

[0109] The following takes the embodiment shown in Figure 8 and Figure 9 as an example to describe the working process of the driving method provided by the embodiment of the present application for the power tube being off.

[0110] Please refer to Figure 6 , Figure 7 , Figure 8 and Figure 9 , in the first stage of the power tube being off, the first NMOS tube M5 and the second NMOS tube M6 are both turned on, and the driving circuit outputs a second off current IG2 to the gate of the power tube. The gate-source voltage of the power tube decreases from a constant maximum value to the Miller voltage Vmiller.

[0111] In the second stage of the power tube being off, the second NMOS tube M6 is turned off, and the third NMOS tube M7 is also turned on, and the driving circuit controls the gate of the power tube to output a current decreasing to a third off current IG3. In the first sub-stage of the second stage, the gate-source voltage of the power tube is stabilized at the Miller voltage Vmiller, and the drain-source voltage of the power tube increases from zero to a constant maximum value. In the second sub-stage of the second stage, the gate-source voltage of the power tube decreases from the Miller voltage Vmiller to the threshold voltage Vth, and the drain-source current of the power tube decreases from a constant maximum value to zero.

[0112] The third stage of the power tube being turned off: the fourth NMOS tube M8 is also turned on, and the driving circuit makes the current output of the gate controlling the power tube rise to the fourth turn-off current IG4. The gate-source voltage of the power tube decreases from the threshold voltage Vth to zero, and the power tube is completely turned off.

[0113] In summary, the driving method provided by the embodiment of the application reduces the reverse recovery current of the corresponding body diode of the power tube by reducing the first turn-on current IG1st to the second turn-on current IG2nd after the gate-source voltage of the power tube rises to the threshold voltage Vth, thereby avoiding overshoot of the power tube in the conduction process, and improving the conduction safety of the power tube.

[0114] Further, the first turn-on current IG1st and the fourth turn-on current are both greater than the third turn-on current IG3rd, so as to accelerate the rate of the power tube in the first stage and the fourth stage of being turned on, thereby improving the conduction efficiency of the power tube on the basis of ensuring the conduction safety of the power tube. Meanwhile, the turn-on current is reduced in the Miller plateau stage of the power tube being turned on, so as to avoid generating an excessively large peak voltage.

[0115] Further, the second turn-off current IG2 and the fourth turn-off current IG4 are both greater than the third turn-off current IG3, so as to accelerate the rate of the power tube in different stages of being turned off, thereby improving the turn-off efficiency of the power tube. Meanwhile, the turn-off current is reduced in the Miller plateau stage of the power tube being turned off and the stage from the Miller plateau to the threshold voltage Vth, so as to avoid generating an excessively large peak voltage and peak current.

[0116] Before the other technical solution of the application is described, the problems existing in the prior art in driving an amplification circuit are described.

[0117] The amplification circuit usually includes a high-side power tube and a low-side power tube. The drain of the high-side power tube is connected to a power supply voltage, the source of the high-side power tube is connected to the drain of the low-side power tube and serves as an output terminal of the amplification circuit, and the source of the second power tube is connected to a ground terminal. When the amplification circuit is driven, the high-side power tube and the low-side power tube are turned on alternately. If there is a phase mismatch between the driving signals of the high-side power tube and the low-side power tube, or if one of the power tubes is not completely turned off due to being larger in size and the other power tube is turned on in advance, the two power tubes may be turned on simultaneously to form a low-resistance path from the power supply to the ground, thereby generating a large current and burning the power device.

[0118] In order to avoid the above situation, the prior art adds a dead time interval between the gate drive signals to ensure that the power tube on the other side is turned on after the power tube on one side is completely turned off. However, the fixed dead time interval may be affected by external environmental factors such as temperature and process, resulting in a fixed dead time interval that is too large or too small. If the dead time interval is too long, it will cause serious nonlinear distortion; if the dead time interval is too short, it will increase the risk of simultaneous conduction of the high-side power tube and the low-side power tube.

[0119] Therefore, the technical scheme of the present application also provides another driving method for driving an amplification module, wherein the amplification module comprises a first power tube and a second power tube, the drain of the first power tube is connected to a power supply voltage, the source of the first power tube is connected to the drain of the second power tube and serves as an output terminal of the amplification module, and the source of the second power tube is connected to a ground terminal.

[0120] The technical scheme of the present application provides another driving method comprising the following steps:

[0121] When the second power tube is turned off, a second gate-source voltage of the second power tube is detected;

[0122] When the second gate-source voltage of the second power tube is less than or equal to a threshold voltage, the first power tube is turned on;

[0123] When the first power tube is turned off, a first gate-source voltage of the first power tube is detected;

[0124] When the first gate-source voltage of the first power tube is less than or equal to the threshold voltage, the second power tube is turned on;

[0125] Wherein, the turning on of the first power tube and the turning on of the second power tube each comprises:

[0126] outputting a first turn-on current to the gate of the power tube to be driven;

[0127] After the gate-source voltage of the power tube to be driven rises to the threshold voltage, the first turn-on current is reduced to a second turn-on current to reduce the reverse recovery current of the body diode corresponding to the power tube to be driven;

[0128] After the gate-source voltage of the power tube to be driven rises from the threshold voltage to a Miller voltage, the second turn-on current is increased to a third turn-on current until the power tube to be driven is completely turned on.

[0129] Through the above technical means, the technical scheme of the present application can adaptively control the dead time interval between the alternating turn-on of the first power tube and the second power tube to avoid the influence of external environmental factors such as temperature and process. The specific reasons are as follows:

[0130] When the first power tube is turned off, the first gate-source voltage of the first power tube is detected. When the first gate-source voltage is less than or equal to the threshold voltage, the second power tube is turned on again. When the second power tube is turned off, the second gate-source voltage of the second power tube is detected. When the second gate-source voltage is less than or equal to the threshold voltage, the first power tube is turned on again.

[0131] Since the turning on of one power tube is anchored with the size of the gate-source voltage of the other power tube in the process of turning off, even if the power tube is affected by external environmental factors such as temperature and process, it can be ensured that the power tube to be turned on will be turned on when the other power tube is completely turned off, thereby effectively avoiding the simultaneous turning on of the first power tube and the second power tube. At the same time, because the turning on of the power tube and the turning off of the other power tube establish a chain relationship, when the power tube is affected by external environmental factors such as temperature and process, the dead time between the turning on of the power tube and the turning off of the other power tube can also be controlled within a reasonable range.

[0132] It should be noted that since the technical means for turning on or turning off a single power tube in this technical solution is the same as the previous technical solution and the corresponding embodiments, the turning on or turning off of the power tube will not be described again.

[0133] As a specific embodiment, the first power tube and the second power tube each include an NMOS tube.

[0134] The technical solution of the present application also provides a driving circuit of an amplification module. The amplification module includes a first power tube Ma and a second power tube Mb, the drain of the first power tube Ma is connected to a power supply voltage VCC, the source of the first power tube Ma is connected to the drain of the second power tube Mb and serves as an output terminal of the amplification module, and the source of the second power tube Mb is connected to a ground terminal.

[0135] Wherein, Figure 10 is a circuit structure schematic diagram of the driving circuit of the amplification module provided by the technical solution of the present application.

[0136] Please refer to Figure 10 The driving circuit of the amplification module provided by the technical solution of the present application includes:

[0137] A first driving module 10, the first driving module 10 is used for turning on or turning off the first power tube Ma according to the driving method provided by the previous technical solution according to the first control signal V1;

[0138] A second driving module 20 is configured to turn on or turn off the second power tube Mb according to a second control signal V2 and the driving method provided in the previous technical solution.

[0139] A bootstrap module 30 is configured to boost the output voltage of the amplification module and take the boosted output voltage as the power supply voltage of the first driving module 10.

[0140] A logic control module 40 is configured to receive an external input control square wave Va and output a first control signal V1 to the level shift module 50 according to the control square wave Va, and the level shift module 50 is configured to perform level conversion on the first control signal V1 and output a second control signal V2 to the first driving module 10, and the logic control module 40 is further configured to output the third control signal V3 to the second driving module 20 according to the control square wave Va.

[0141] A threshold detection module 60 is configured to detect the first gate-source voltage of the first power tube Ma and output to the logic control module 40, and the threshold detection module 60 is further configured to detect the second gate-source voltage of the second power tube Mb and output to the logic control module 40.

[0142] The logic control module 40 is further configured to output the second control signal V2 to make the second driving module 20 control the second power tube Mb to turn on according to the first gate-source voltage being less than a threshold voltage Vth when the first power tube Ma is turned off, and the logic control module 40 is further configured to output the first control signal V1 to make the first driving module 10 control the first power tube Ma to turn on according to the second gate-source voltage being less than the threshold voltage Vth when the second power tube Mb is turned off.

[0143] In the present application, the driving circuit and the corresponding amplification module are particularly applied in a class-D power amplifier. Of course, the driving circuit provided in the present application is also applicable to other circuit structures that need to set an amplification module, which is not limited herein.

[0144] The present application further provides an electronic device comprising the driving circuit of the amplification module.

[0145] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present application, and the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A driving method for driving a power transistor, characterized in that, The method includes: When the power transistor is turned on: The first on-state current is output to the gate of the power transistor; After the gate-source voltage of the power transistor rises to the threshold voltage, the first on-current is reduced to the second on-current to reduce the reverse recovery current of the corresponding body diode of the power transistor. After the gate-source voltage of the power transistor rises from the threshold voltage to the Miller voltage, the second on-current is increased to the third on-current until the power transistor is fully turned on. When the power transistor is turned off: The gate of the power transistor is turned off by a first shutdown current until the power transistor is completely turned off. Also includes: After the gate of the power transistor outputs a first turn-off current, the gate of the power transistor outputs a second turn-off current; after the gate-source voltage of the power transistor drops to the Miller voltage, the second turn-off current is reduced to a third turn-off current; after the gate-source voltage of the power transistor drops to the threshold voltage, the third turn-off current is increased to a fourth turn-off current until the power transistor is completely turned off.

2. The driving method according to claim 1, characterized in that, The first on-current is set to be greater than the third on-current.

3. The driving method according to claim 2, characterized in that, After increasing the second conduction current to the third conduction current, the method further includes: After the drain-source voltage of the power transistor drops to zero, the third on-current is increased to the fourth on-current.

4. A driving method for driving an amplification module, characterized in that, The amplification module includes a first power transistor and a second power transistor. The drain of the first power transistor is connected to the power supply voltage, and the source of the first power transistor is connected to the drain of the second power transistor and serves as the output terminal of the amplification module. The source of the second power transistor is connected to ground. The method includes: When the second power transistor is turned off, the second gate-source voltage of the second power transistor is detected; When the second gate-source voltage of the second power transistor is less than or equal to the threshold voltage, the first power transistor is turned on. When the first power transistor is turned off, the first gate-source voltage of the first power transistor is detected; When the first gate-source voltage of the first power transistor is less than or equal to the threshold voltage, the second power transistor is turned on. The process of turning on the first power transistor and turning on the second power transistor both include: Output the first on-current to the gate of the power transistor to be driven; After the gate-source voltage of the power transistor to be driven rises to the threshold voltage, the first on-current is reduced to the second on-current to reduce the reverse recovery current of the corresponding body diode of the power transistor to be driven. After the gate-source voltage of the power transistor to be driven rises from the threshold voltage to the Miller voltage, the second on-current is increased to the third on-current until the power transistor to be driven is fully turned on. The process of turning off the first power transistor and turning off the second power transistor both include: The gate of the power transistor is turned off by a first shutdown current until the power transistor is completely turned off. It also includes: after the gate of the power transistor outputs a first turn-off current, causing the gate of the power transistor to output a second turn-off current; after the gate-source voltage of the power transistor drops to the Miller voltage, reducing the second turn-off current to a third turn-off current; and after the gate-source voltage of the power transistor drops to the threshold voltage, increasing the third turn-off current to a fourth turn-off current until the power transistor is completely turned off.

5. The driving method according to claim 4, characterized in that, The first on-current is set to be greater than the third on-current.

6. The driving method according to claim 5, characterized in that, After increasing the second conduction current to the third conduction current, the method further includes: After the drain-source voltage of the power transistor drops to zero, the third on-current is increased to the fourth on-current.

7. The driving method according to claim 4, characterized in that, Both the first power transistor and the second power transistor include an NMOS transistor.

8. A driving circuit for an amplification module, characterized in that, The amplification module includes a first power transistor and a second power transistor. The drain of the first power transistor is connected to the power supply voltage, and the source of the first power transistor is connected to the drain of the second power transistor and serves as the output terminal of the amplification module. The source of the second power transistor is connected to ground. The driving circuit includes: A first driving module is configured to turn on or off the first power transistor according to a first control signal and the driving method according to any one of claims 1 to 3. The second driving module is used to turn the second power transistor on or off according to the driving method described in any one of claims 1 to 3, based on a second control signal. The bootstrap module is used to boost the output voltage of the amplification module and use the boosted output voltage as the power supply voltage of the first drive module. The system includes a logic control module and a level shifting module. The logic control module receives a control square wave input from the outside and outputs a first control signal to the level shifting module based on the control square wave. The level shifting module performs level conversion on the first control signal and outputs a second control signal to the first driving module. The logic control module also outputs a third control signal to the second driving module based on the control square wave. A threshold detection module is configured to detect the first gate-source voltage of the first power transistor and output it to the logic control module; the threshold detection module is also configured to detect the second gate-source voltage of the second power transistor and output it to the logic control module. The logic control module is further configured to, when the first power transistor is turned off, output a second control signal based on the first gate-source voltage being less than a threshold voltage, so as to enable the second driving module to control the second power transistor to turn on; the logic control module is further configured to, when the second power transistor is turned off, output a first control signal based on the second gate-source voltage being less than a threshold voltage, so as to enable the first driving module to control the first power transistor to turn on.

9. An electronic device, characterized in that, The driving circuit includes the amplification module as described in claim 8.

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