阅读说明：本技术 一种驱动电路 (Driving circuit ) 是由 吴新科 李光灿 于 2021-01-05 设计创作，主要内容包括：本发明公开了一种驱动电路,包括信号输出装置及电感,信号输出装置能够输出交流控制信号,从而驱动开关管,交流控制信号中包括死区,当交流控制信号处于死区时,电感与开关管中的等效门极电容谐振,等效门极电容中的部分能量被存储至电感中,且通过设置电感,使流经开关管的等效电阻的电流不能突变,且小于未连接电感时的电流,因此,使消耗在开关管的等效电阻上的能量减少,也即使驱动电路中的能耗减少。(The invention discloses a driving circuit, which comprises a signal output device and an inductor, wherein the signal output device can output an alternating current control signal so as to drive a switching tube, the alternating current control signal comprises a dead zone, when the alternating current control signal is in the dead zone, the inductor resonates with an equivalent gate electrode capacitor in the switching tube, partial energy in the equivalent gate electrode capacitor is stored into the inductor, and the current flowing through the equivalent resistor of the switching tube cannot suddenly change and is smaller than the current when the inductor is not connected through setting the inductor, so that the energy consumed on the equivalent resistor of the switching tube is reduced, namely the energy consumption in the driving circuit is reduced.)

1. A driver circuit, comprising:

the signal output device is used for outputting an alternating current control signal to drive the switching tube, and the alternating current control signal comprises a dead zone;

and the inductor is used for resonating the dead time of the alternating current control signal and the equivalent gate pole capacitance in the switch tube.

2. The drive circuit according to claim 1, wherein the signal output means includes:

a DC power supply for outputting a DC voltage;

the first input end is connected with the positive output end of the direct-current power supply, the second input end is connected with the negative output end of the direct-current power supply, the first output end is the first output end of the signal output device is connected with the first end of the inductor, the second output end is connected with the second output end of the signal output end and the inverter circuit connected with the second end of the inductor, the inverter circuit is used for converting the direct-current voltage into alternating-current voltage in an inverse mode to output an alternating-current control signal to drive the switch tube, and the alternating-current control signal comprises a dead zone.

3. The driving circuit according to claim 2, wherein the inverter circuit is a bridge circuit having a first input terminal connected to the positive output terminal of the dc power source, a second input terminal connected to the negative output terminal of the dc power source, a first output terminal connected to the first output terminal of the inverter circuit and the first end of the inductor, and a second output terminal connected to the second output terminal of the inverter circuit and the second end of the inductor, and configured to invert the dc voltage into an ac voltage to output an ac control signal, the ac control signal including a dead zone; and clamping the alternating current control signal to enable the alternating current control signal to be smaller than the gate breakdown voltage of the switching tube.

4. The driving circuit of claim 3, wherein the bridge circuit is a half-bridge switching tube circuit, a full-bridge switching tube circuit, a push-pull circuit, or an active clamp circuit.

5. The drive circuit according to claim 3, wherein the switching tube is plural;

the drive circuit further includes:

and the transformer is connected between the inductor and each switching tube and is used for transmitting the alternating current control signal to the switching tubes and isolating the alternating current control signal between the switching tubes.

6. The drive circuit of claim 5 wherein said inductance is formed by an excitation inductance of the primary side of said transformer.

7. The driving circuit of claim 5, wherein the transformer is a planar transformer or a wound transformer.

8. The driving circuit as claimed in claim 5, wherein the switching transistor is a metal oxide semiconductor field effect transistor (MOS) transistor.

Technical Field

The present invention relates to the field of power electronics, and more particularly, to a driving circuit.

Background

In the power module, when the switching frequency is high, the driving loss is large, and when the conventional voltage-type driving circuit or driving chip is applied, the equivalent circuit thereof refers to fig. 1, where fig. 1 is a schematic structural diagram of the equivalent circuit of the voltage-type driving circuit in the prior art, where Cgs is an equivalent gate capacitance of the switching tube, and Rg is an equivalent resistance, i.e., a sum of the gate resistance of the switching tube and a loop parasitic resistance. In the voltage-type driving circuit, the driving circuit can be equivalent to an RC (resistor-capacitor) charging and discharging circuit when the equivalent gate capacitance Cgs of the switching tube is charged and discharged, and the energy in the equivalent gate capacitance Cgs of the switching tube is totally dissipated on the equivalent resistance Rg in one switching period. When the equivalent gate capacitance Cgs of the switching tube is large or the number of the switching tubes is large and the switching frequency of the switching tubes is high, a very large driving loss is caused, and the efficiency of the circuit is seriously influenced.

Disclosure of Invention

The present invention provides a driving circuit, which can prevent the current flowing through the equivalent resistor of the switch tube from sudden change and is smaller than the current when the inductor is not connected by arranging the inductor, thereby reducing the energy consumed on the equivalent resistor of the switch tube, i.e. reducing the energy consumption in the driving circuit.

To solve the above technical problem, the present invention provides a driving circuit, including:

the signal output device is used for outputting an alternating current control signal to drive the switching tube, and the alternating current control signal comprises a dead zone;

and the inductor is used for resonating the dead time of the alternating current control signal and the equivalent gate pole capacitance in the switch tube.

Preferably, the signal output device includes:

a DC power supply for outputting a DC voltage;

the first input end is connected with the positive output end of the direct-current power supply, the second input end is connected with the negative output end of the direct-current power supply, the first output end is the first output end of the signal output device is connected with the first end of the inductor, the second output end is connected with the second output end of the signal output end and the inverter circuit connected with the second end of the inductor, the inverter circuit is used for converting the direct-current voltage into alternating-current voltage in an inverse mode to output an alternating-current control signal to drive the switch tube, and the alternating-current control signal comprises a dead zone.

Preferably, the inverter circuit is a bridge circuit having a first input end connected to the positive output end of the dc power supply, a second input end connected to the negative output end of the dc power supply, a first output end connected to the first output end of the inverter circuit, and a second output end connected to the second output end of the inductor, and configured to invert the dc voltage into an ac voltage to output an ac control signal to drive the switching tube, where the ac control signal includes a dead zone; and clamping the alternating current control signal to enable the alternating current control signal to be smaller than the gate breakdown voltage of the switching tube.

Preferably, the bridge circuit is a half-bridge switching tube circuit, a full-bridge switching tube circuit, a push-pull circuit or an active clamping circuit.

Preferably, the switch tube is multiple;

the drive circuit further includes:

and the transformer is connected between the inductor and each switching tube and is used for transmitting the alternating current control signal to the switching tubes and isolating the alternating current control signal between the switching tubes.

Preferably, the inductor is formed by an excitation inductor on the primary side of the transformer.

Preferably, the transformer is a planar transformer or a wound transformer.

Preferably, the switch tube is a metal oxide semiconductor field effect transistor (MOS) tube.

The application provides a drive circuit, including signal output device and inductance, signal output device can output alternating current control signal, thereby drive the switch tube, including the dead zone in the alternating current control signal, when alternating current control signal is in the dead zone, inductance and the resonance of the equivalent gate pole electric capacity in the switch tube, some energy in the equivalent gate pole electric capacity is stored to the inductance, and through setting up the inductance, make the electric current of the equivalent resistance of switch tube of flowing through can not break suddenly, and be less than the electric current when not connecting the inductance, consequently, make the energy of consuming on the equivalent resistance of switch tube reduce, also make the energy consumption in the drive circuit reduce.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed in the prior art and the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of an equivalent circuit of a voltage-type driving circuit in the prior art;

FIG. 2 is a schematic structural diagram of a driving circuit according to the present invention;

FIG. 3 is a schematic structural diagram of a driving circuit with an inverter circuit according to the present invention;

fig. 4 is a schematic structural diagram of a driving circuit provided in the present invention;

FIG. 5 is a waveform diagram illustrating the variation of key parameters in the driving circuit according to the present invention;

FIG. 6 is a schematic diagram of an operation mode of the driving circuit according to the present invention;

FIG. 7 is a schematic diagram illustrating another operating mode of the driving circuit according to the present invention;

fig. 8 is a schematic diagram of a first modification of the driving circuit of the half-bridge configuration provided in the present invention;

fig. 9 is a key waveform diagram of a first improvement of a driving circuit of a half-bridge structure provided by the present invention;

fig. 10 is a schematic diagram of a second improvement of the driving circuit of the half-bridge structure provided by the present invention;

fig. 11 is a key waveform diagram of a second modification of the driving circuit of the half-bridge configuration provided by the present invention;

fig. 12 is a schematic diagram of a third modification of the driving circuit of the half-bridge configuration provided in the present invention;

fig. 13 is a schematic diagram of another driving circuit of a half-bridge configuration according to the present invention;

fig. 14 is a schematic diagram of a first modification of a driving circuit of another half-bridge structure provided in the present invention;

fig. 15 is a schematic diagram of a second modification of the driving circuit of the half-bridge structure provided in the present invention;

fig. 16 is a schematic diagram of a third modification of the driving circuit of another half-bridge structure provided in the present invention;

fig. 17 is a schematic structural diagram of a driving circuit of a full-bridge structure according to the present invention;

fig. 18 is a schematic structural diagram of a first modification of the driving circuit of the full-bridge configuration provided by the present invention;

fig. 19 is a schematic structural diagram of a second modification of the driving circuit of the full-bridge configuration provided by the present invention;

fig. 20 is a schematic structural diagram of a third modification of the driving circuit of the full-bridge configuration provided by the present invention;

fig. 21 is a schematic structural diagram of a driving circuit of a push-pull structure according to the present invention;

fig. 22 is a schematic structural diagram of a first modification of the driving circuit of the push-pull configuration provided in the present invention;

fig. 23 is a schematic structural diagram of a second modification of the driving circuit of the push-pull configuration provided in the present invention;

fig. 24 is a schematic structural diagram of a third modification of the driving circuit of the push-pull configuration provided by the present invention;

FIG. 25 is a schematic diagram of a driving circuit of an active clamping structure according to the present invention;

FIG. 26 is a schematic diagram of a first modified driving circuit of an active clamp structure according to the present invention;

FIG. 27 is a diagram illustrating a second modified driving circuit of an active clamp structure according to the present invention;

fig. 28 is a schematic diagram of a third modified driving circuit of an active clamp structure according to the present invention.

Detailed Description

The core of the invention is to provide a driving circuit, which can prevent the current flowing through the equivalent resistance of the switching tube from sudden change and is smaller than the current when the inductance is not connected by arranging the inductance, thereby reducing the energy consumed on the equivalent resistance of the switching tube, namely reducing the energy consumption in the driving circuit.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a driving circuit provided in the present invention.

The drive circuit includes:

the signal output device 1 is used for outputting an alternating current control signal to drive the switching tube 3, and the alternating current control signal comprises a dead zone;

the inductor 2 is connected with the first output end of the signal output device 1 and the control end of the switch tube 3 at the first end, and is connected with the second output end of the signal output device 1 and one end of the switch tube 3 at the second end, and is used for resonating at the dead time of the alternating current control signal and the equivalent gate pole capacitor Cgs in the switch tube 3.

In the power module in the prior art, a power supply U outputs a control signal to drive a switching tube 3, the switching tube 3 can be equivalent to an equivalent gate capacitor Cgs connected to an equivalent resistor Rgs, as shown in fig. 1, when the switching frequency of the switching tube 3 is high, that is, the equivalent gate capacitor Cgs of the switching tube 3 is frequently charged and discharged, in a voltage-type driving circuit, the equivalent gate capacitor Cgs of the switching tube 3 is equivalent to an RC charging and discharging circuit during charging and discharging, the energy of the equivalent gate capacitor Cgs of the switching tube 3 in one switching period is consumed by the equivalent resistor Rgs, and when the equivalent gate capacitor Cgs of the switching tube 3 is large, the gate capacitor Cgs stores more electric energy and the gate capacitor Cgs consumes more electric energy; when the number of the switching tubes 3 is large and the switching frequency of the switching tubes 3 is high, the electric energy consumed by the equivalent resistance Rgs is also large, which also causes large loss, affects the efficiency of the circuit, and particularly has a large influence on whether the driving circuit can normally work in a light load state or a half load state.

In order to solve the above technical problem, in the present application, an inductor 2 is disposed between a signal output device 1 and a switching tube 3, the signal output device 1 is capable of outputting an ac control signal to drive the switching tube 3, the ac control signal includes a dead zone, the inductor 2 and an equivalent gate capacitor Cgs in the switching tube 3 resonate during the dead zone time of the ac control signal, a part of energy in the equivalent gate capacitor Cgs is stored in the inductor 2, and since the current flowing through the inductor 2 cannot suddenly change, the current flowing through the equivalent resistor Rgs of the switching tube 3 is also smaller, the energy consumed on the resistor is also smaller, and it can be known from the law of conservation of energy that a part of energy in the equivalent gate capacitor Cgs in the switching tube 3 is stored in the inductor 2 and is less than the energy consumed on the equivalent gate capacitor Rgs when the inductor 2 is not disposed, that is, the inductor 2 recovers the energy in the equivalent gate capacitor Cgs of the switching tube 3, the losses in the drive circuit are reduced.

In addition, the signal output device 1 outputs the ac control signal including a high level state, a low level state and a high impedance state, i.e. a state when there is a dead zone in the ac control signal.

It should be noted that the signal output device 1 in the present application may be, but is not limited to, a device formed by a square wave power supply and a switch connected in series, specifically, the square wave power supply can output a square wave ac signal, when the switching tube 3 starts to perform a switching action, that is, when the voltage at two ends of the equivalent gate capacitance Cgs starts to change, the switch is turned off, that is, the ac control signal enters a dead zone, so that the switching tube 3 does not have an input of a control signal, at this time, the inductor 2 and the equivalent gate capacitance Cgs of the switching tube 3 form a loop, and the inductor 2 and the equivalent gate capacitance Cgs resonate, thereby realizing the recovery of the electric energy in the equivalent gate capacitance Cgs by the inductor; when the voltage in the equivalent gate capacitance Cgs is reversed and the absolute value of the voltage at the two ends of the equivalent gate capacitance Cgs reaches the clamping voltage (the clamping voltage is a voltage smaller than the gate breakdown voltage of the switching tube 3), the switch is closed, namely the alternating current control signal ends the dead zone, and the square wave alternating current signal is in a high level or low level state correspondingly.

In addition, in the present application, the time of the dead zone in the ac control signal is not limited, and it is sufficient to recover the electric energy of the equivalent gate capacitance Cgs of the switching tube 3 by the inductor 2 and to perform high-low level switching of the ac control signal.

In addition, the inductance value of the inductor 2 can be changed in the present application to adjust the driving signal of the switching tube 3.

In summary, in the present application, when the ac control signal is in the dead zone, the inductor 2 resonates with the equivalent gate capacitor Cgs in the switching tube 3, a part of energy in the equivalent gate capacitor Cgs is stored in the inductor 2, and the current flowing through the equivalent resistor Rgs of the switching tube 3 cannot suddenly change and is smaller than the current when the inductor 2 is not connected, so that the energy consumed by the equivalent resistor Rgs of the switching tube 3 is reduced, that is, the energy consumption in the driving circuit is reduced.

On the basis of the above-described embodiment:

as a preferred embodiment, the signal output apparatus 1 includes:

a direct current power supply Ve for outputting a direct current voltage;

the first input end is connected with the positive output end of the direct current power supply Ve, the second input end is connected with the negative output end of the direct current power supply Ve, the first output end is the first output end of the signal output device 1 and is connected with the first end of the inductor 2, and the second output end of the second output end and the signal output end is connected with the inverter circuit of the second end of the inductor 2 and is used for converting the direct current voltage into the alternating current voltage in an inverse mode to output the alternating current control signal to drive the switch tube 3, wherein the alternating current control signal comprises a dead zone.

In this embodiment, referring to fig. 3, fig. 3 is a schematic structural diagram of a driving circuit with an inverter circuit according to the present invention. Direct current power supply Ve and inverter circuit have constituted signal output module, and direct current power supply Ve can output direct current voltage, and the voltage value of the direct current voltage of direct current voltage Ve output is Ve, and inverter circuit carries out the contravariant with the direct current voltage of direct current power supply Ve output to output alternating voltage, alternating voltage drives switch tube 3 as alternating current control signal, controls through the output to inverter circuit, can realize including the dead zone in the alternating current control signal of inverter circuit output. It can be seen that the signal output apparatus 1 in this embodiment can output not only the ac control signal including the dead zone, but also a simple circuit structure.

It should be noted that the inverter circuit in the present application may include, but is not limited to, a full bridge circuit, a half bridge circuit, a push-pull circuit, or an active clamp circuit.

In addition, the dc power source Ve in the present application may be, but is not limited to, a dc voltage source.

As a preferred embodiment, the inverter circuit is a bridge circuit in which a first input terminal of the inverter circuit is connected to a positive output terminal of the dc power supply Ve, a second input terminal of the inverter circuit is connected to a negative output terminal of the dc power supply Ve, a first output terminal of the inverter circuit is connected to a first terminal of the inductor 2, and a second output terminal of the inverter circuit is connected to a second terminal of the inductor 2, and is configured to invert the dc voltage into an ac voltage to output an ac control signal, which includes a dead zone, to drive the switching tube 3; and clamping the alternating current control signal to make the alternating current control signal smaller than the gate breakdown voltage of the switching tube 3.

In this embodiment, it is considered that the inverter circuit needs to output an ac voltage as an ac control signal, and the ac control signal further includes a dead zone, so that the inverter circuit in this application is set as a bridge circuit to invert the dc power supply Ve, output the ac control signal, and clamp the ac control signal, so that the ac control signal is smaller than the gate breakdown voltage of the switching tube 3, thereby preventing the gate breakdown of the switching tube 3 due to the excessive driving voltage of the switching tube 3.

In a preferred embodiment, the bridge circuit is a half-bridge switching tube circuit, a full-bridge switching tube circuit, a push-pull circuit or an active clamp circuit.

The bridge circuit in this embodiment may be, but not limited to, a half-bridge switching tube circuit, a full-bridge switching tube circuit, a push-pull circuit, or an active clamp circuit, and the half-bridge switching tube circuit, the full-bridge switching tube circuit, the push-pull circuit, or the active clamp circuit can all invert the dc power Ve, and the control method is simple.

The half-bridge switch tube circuit, the full-bridge switch tube circuit, the push-pull circuit or the active clamping circuit are internally provided with switch tubes, for example, the two ends of each switch tube are respectively connected with a diode and a capacitor in parallel, or the body pole tube and the body capacitor of each half-bridge switch tube can be directly multiplexed, so that the cost is reduced.

As a preferred embodiment, the switch tube 3 is plural;

the drive circuit further includes:

and the transformer is connected between the inductor 2 and each switching tube 3 and is used for transmitting the alternating current control signal to the switching tube 3 and isolating the alternating current control signal between the switching tubes 3.

In this embodiment, considering that there is a need to drive a plurality of switching tubes 3 simultaneously in the prior art, if a driving chip or a driving circuit is provided for each switching tube 3, the number of driving chips or driving circuits required is large, the cost is also high, and isolation type driving chips are also needed to be used for signal isolation between different switching tubes 3, which further increases the cost.

In order to solve the above problem, in this embodiment, a transformer is disposed between the inductor 2 and each of the switching tubes 3, the transformer includes a primary winding and a secondary winding, and the transformer may include a plurality of secondary windings, each of the switching tubes 3 is connected to one of the secondary windings, and the secondary windings of the transformer corresponding to each of the switching tubes 3 and the winding manner corresponding to the primary winding are respectively set based on the on/off requirement of the switching tube 3.

Referring to fig. 4, a specific connection manner of the bridge circuit is a half-bridge switching tube circuit, and fig. 4 is a specific structural schematic diagram of the driving circuit provided by the present invention. In the figure, two switching tubes 3 are taken as an example, one end of a first secondary winding of the transformer is connected with a gate electrode of the first switching tube S1, and the other end of the first secondary winding of the transformer is connected with a source electrode of the first switching tube S1, and when a plurality of switching tubes are arranged, the connection mode of each switching tube Sn is similar to that of the first switching tube S1, so that the transformer can transmit a primary alternating current control signal to the secondary switching tube 3 to drive the switching tube 3, and can isolate each switching tube 3, and the circuit is simple in structure, strong in expansibility and low in cost.

In this embodiment, the present embodiment is describedReferring to fig. 5, fig. 5 is a waveform diagram of a variation of a key parameter in the driving circuit provided by the present invention, wherein the waveform diagram includes a schematic diagram of control signals of the first half-bridge switch Q1 and the second half-bridge switch Q2 in the middle half-bridge switch tube circuit, a schematic diagram of a current flowing through the inductor 2, and a schematic diagram of a variation of a voltage Vgs1 across the first switch tube S1 and a variation of a voltage Vgs2 across the second switch tube S2 in the switch tube 3. It can be seen that Vg _ Q1 is a driving signal of the first half-bridge switch Q1 in the half-bridge switch tube circuit, Vg _ Q2 is a driving signal of the second half-bridge switch Q2 in the half-bridge switch tube circuit, i_LmFor the current flowing through the inductor 2, Vgs1 is the voltage across the equivalent gate capacitance Cgs1 of the first switching transistor S1, and Vgs2 is the voltage across the equivalent gate capacitance Cgs2 of the second switching transistor S2.

Because the capacitance values of the half-bridge capacitor C1 and the half-bridge capacitor C2 in the half-bridge capacitor circuit in fig. 4 are large, the voltages at the two ends of the circuit are approximately unchanged when the circuit operates in a steady state, and the circuit can be regarded as the voltage source VC1 and the voltage source VC2 when the circuit operates in a modal analysis.

Fig. 6 shows an equivalent circuit diagram of the driving circuit when the first half-bridge switching transistor Q1 is turned on, and fig. 6 is a schematic diagram of an operation mode of the driving circuit provided by the present invention. In the figure, two switching tubes 3 are connected as an example, in the figure, VC2 is a voltage source equivalent to a second capacitor C2, Cgs1 is an equivalent gate capacitor of a first switching tube S1, Cgs2 is an equivalent gate capacitor of a second switching tube S2, a secondary winding of a transformer connected with the equivalent gate capacitor Cgs1 is wound in the same direction as a primary winding of the transformer, a secondary winding of the transformer connected with the equivalent gate capacitor Cgs2 is wound in the opposite direction to the primary winding of the transformer, and as shown in fig. 5, at t, the winding direction is opposite to that of the primary winding of the transformer₀At the moment, the first half-bridge switch tube Q1 is conducted, the voltage of the second capacitor C2 is Ve/2, therefore, the voltage of the primary winding of the transformer is clamped at Ve/2, and when the turn ratio of the primary side and the secondary side of the transformer is set to be 1:1, the voltage Vgs1 of the equivalent gate capacitor Cgs1 of the secondary side is clamped at Ve/2. The voltage across the inductor 2 is equal to the voltage across the primary winding, so that the voltage across the inductor 2 transitions from negative to positive; t is t₁At this time, the first half-bridge switching transistor Q1 is turned off. Since the secondary winding of the transformer is connected to the equivalent gate capacitance Cgs of the switching tube 3, the voltage of the secondary winding of the transformer does not suddenly change, becauseThe voltage of the primary winding does not suddenly change, namely the drain-source voltage of the first half-bridge switching tube Q1 is approximately 0 when being turned off, and the primary winding has a zero-voltage turn-off characteristic.

Fig. 7 shows an equivalent circuit diagram of the driving circuit when the first half-bridge switching transistor Q1 and the second half-bridge switching transistor Q2 are both turned off, and fig. 7 is a schematic diagram of another operation mode of the driving circuit provided by the present invention. t is t₁At the moment, the first half-bridge switching tube Q1 and the second half-bridge switching tube Q2 are both in an off state, and since a forward current exists in the inductor 2 at the moment, the current in the inductor 2 resonates with an equivalent gate capacitor on the secondary side through the transformer, so that high and low level conversion of the driving signal is performed. When Vgs1 is converted from + Ve/2 to-Ve/2, the drain-source voltage of the second half-bridge switching tube Q2 is zero, zero-voltage switching-on is realized, and the secondary side Cgs1 is clamped at-Ve/2 by the primary side. The second half-bridge switching tube Q2 is turned on, the mode when the first half-bridge switching tube Q1 is turned off is turned on with the first half-bridge switching tube Q1, and the process of the mode when the second half-bridge switching tube Q2 is turned off is similar, which is not described herein again.

In addition, the present application further provides an improved circuit when the bridge circuit is a half-bridge switching tube circuit, please refer to fig. 8, fig. 8 is a schematic structural diagram of a first improvement of the driving circuit of the half-bridge structure provided by the present invention, in the diagram, two switching tubes 3 are arranged behind the same secondary winding of the transformer, which are respectively a first switching tube S1 and a second switching tube S2, and a first auxiliary switching tube Q is connected between the secondary winding of the transformer and the switching tube 3_M1And a second auxiliary switch tube Q_M2First auxiliary switch tube Q_M1And a second auxiliary switch tube Q_M2The negative half-wave of the voltage Vgs across the equivalent gate capacitance Cgs of the switching tube 3 can be filtered out, and only the positive half-wave remains, where g is the gate of the switching tube 3, S is the source of the switching tube 3, and the equivalent gate capacitance Cgs of the switching tube 3 is the gate-source capacitance of the switching tube 3, please refer to fig. 9 for waveforms, and fig. 9 is a first improved key waveform diagram of the driving circuit with a half-bridge structure provided in the present invention, it can be seen that the voltage Vgs1 across the equivalent gate capacitance Cgs1 of the first switching tube S1 in the diagram contains only the positive half-wave, and the voltage Vgs2 across the equivalent gate capacitance Cgs2 of the second switching tube S2 also contains only the positive half-wave, which needs to be explainedThat is, the first auxiliary switch tube Q_M1And a second auxiliary switch tube Q_M2Is less than the turn-on threshold voltages of the first switch tube S1 and the second switch tube S2.

Referring to fig. 10, fig. 10 is a schematic diagram of a second improved structure of the driving circuit of the half-bridge structure provided by the present invention, it can be seen that only one switching tube 3, i.e. the first switching tube S1, is arranged behind one secondary winding of the transformer in the figure, and a first auxiliary switching tube Q is connected between the secondary winding of the transformer and the switching tube 3_M1And a second auxiliary switch tube Q_M2First auxiliary switch tube Q_M1And a second auxiliary switch tube Q_M2Referring to fig. 11, fig. 11 is a key waveform diagram of a second improvement of the driving circuit of the half-bridge structure provided in the present invention, and it can be seen that the voltage Vgs1 across the equivalent gate capacitor Cgs1 of the first switching tube S1 in the figure only contains a positive half-wave. Auxiliary capacitor C in the figure_M0A second switching tube S2 corresponding to the driving in place of the first modified circuit; wherein, the first auxiliary switch tube Q_M1And a second auxiliary switch tube Q_M2Is less than the turn-on threshold voltages of the first switch tube S1 and the second switch tube S2, and the auxiliary capacitor C_M0The capacitance value of (c) is close to the equivalent gate capacitance Cgs1 of the first switch tube S1, and the error is not more than +/-40%.

Referring to fig. 12, fig. 12 is a schematic structural diagram of a third improvement of the driving circuit of the half-bridge structure provided by the present invention, and it can be seen that, in the drawing, only one switching tube 3 is arranged behind one secondary winding of the transformer, and two secondary windings are arranged, each secondary winding is respectively provided with one switching tube 3, namely, a first switching tube S1 and a second switching tube S2, and a first auxiliary switching tube Q is connected between the first secondary winding of the transformer and the first switching tube S1_M1And a second auxiliary switch tube Q_M2Between the second secondary winding of the transformer and the second switch tube S2A third auxiliary switch tube Q is connected between_M3And a fourth auxiliary switch tube Q_M4First auxiliary switch tube Q_M1And a second auxiliary switch tube Q_M2The negative half wave of the voltage Vgs1 applied to the two ends of the equivalent gate capacitance Cgs1 of the first switch tube S1 can be filtered out, only the positive half wave is left, and the third auxiliary switch tube Q_M3And a fourth auxiliary switch tube Q_M4The negative half-wave of the voltage Vgs2 across the equivalent gate capacitor Cgs2 of the second switching tube S2 can be filtered out, and only the positive half-wave remains, and referring to fig. 9, it can be seen that the voltage Vgs1 across the equivalent gate capacitor Cgs1 of the first switching tube S1 in the figure contains only the positive half-wave, and the voltage Vgs2 across the equivalent gate capacitor Cgs2 of the second switching tube S2 also contains only the positive half-wave. Wherein, the first auxiliary switch tube Q_M1A second auxiliary switch tube Q_M2And a third auxiliary switch tube Q_M3And a fourth auxiliary switch tube Q_M4Is less than the turn-on threshold voltages of the first switch tube S1 and the second switch tube S2.

Referring to fig. 13, fig. 13 is a schematic structural diagram of another half-bridge driving circuit according to the present invention, and it can be seen that only one capacitor C is provided in the diagram₂Fig. 14, 15 and 16 are shown, fig. 14 is a schematic diagram of a first improved structure of another driving circuit with a half-bridge structure provided by the present invention, fig. 15 is a schematic diagram of a second improved structure of another driving circuit with a half-bridge structure provided by the present invention, fig. 16 is a schematic diagram of a third improved structure of another driving circuit with a half-bridge structure provided by the present invention, and the description of the three improvements of the another driving circuit with a half-bridge structure is described with reference to the description of the three improvements when the bridge circuit is a half-bridge switching tube circuit, which is not repeated herein.

The present application further provides a driving circuit when the inverter circuit is a full-bridge switching tube circuit, please refer to fig. 17, fig. 17 is a schematic structural diagram of the driving circuit of the full-bridge structure provided by the present invention, it can be seen that, in the diagram, four switching tubes are provided in the full-bridge circuit, in addition, fig. 18, fig. 19 and fig. 20 are referred to for a circuit obtained by modifying the driving circuit when the inverter circuit is a full-bridge switching tube circuit, fig. 18 is a schematic structural diagram of a first modification of the driving circuit of the full-bridge structure provided by the present invention, fig. 19 is a schematic structural diagram of a second modification of the driving circuit of the full-bridge structure provided by the present invention, fig. 20 is a schematic structural diagram of a third modification of the driving circuit of the full-bridge structure provided by the present invention, and the above-mentioned description of three modifications of the driving circuit of the full-bridge structure refers to the description of three modifications of the, and will not be described in detail herein.

Referring to fig. 21, fig. 21 is a schematic structural diagram of a driving circuit of a push-pull structure provided by the present invention, and it can be seen that the push-pull circuit in the figure is provided with two switching tubes and two primary windings, each switching tube is connected in series with one primary winding, one switching tube is connected to the same-name end of one primary winding, and the other switching tube is connected to the other end of the other primary winding. In addition, please refer to fig. 22, fig. 23, and fig. 24 for a circuit obtained by improving a driving circuit when the inverter circuit is a push-pull circuit, where fig. 22 is a schematic diagram of a first improved structure of the driving circuit with a push-pull structure provided by the present invention, fig. 23 is a schematic diagram of a second improved structure of the driving circuit with a push-pull structure provided by the present invention, and fig. 24 is a schematic diagram of a third improved structure of the driving circuit with a push-pull structure provided by the present invention, and the description of the three improvements of the driving circuit with a push-pull structure refers to the description of the three improvements when the bridge circuit is a half-bridge switching tube circuit, which is not repeated herein.

Referring to fig. 25, fig. 25 is a schematic structural diagram of a driving circuit of an active clamping structure provided by the present invention, and it can be seen that the active clamping circuit in the figure is provided with two switching tubes and an auxiliary capacitor C1, wherein a main switching tube Q1 is connected to a primary winding of a transformer, and an auxiliary switching tube Q2 is connected in series with the capacitor C1 and then connected in parallel to two ends of the primary winding of the transformer. The capacitance of the capacitor C1 is much larger than the sum of the capacitances of the gate capacitances of the driven switching tubes, for example, the capacitance of the capacitor C1 is more than 50 times larger than the sum of the capacitances of the gate capacitances of the driven switching tubes. In addition, please refer to fig. 26, fig. 27, and fig. 28 for a circuit obtained by improving a driving circuit when the inverter circuit is an active clamping circuit, fig. 26 is a schematic diagram of a first improved structure of the driving circuit of the active clamping structure provided by the present invention, fig. 27 is a schematic diagram of a second improved structure of the driving circuit of the active clamping structure provided by the present invention, fig. 28 is a schematic diagram of a third improved structure of the driving circuit of the active clamping structure provided by the present invention, and the description of the three improvements of the driving circuit of the active clamping structure refers to the description of the three improvements when the bridge circuit is a half-bridge switching tube circuit, which is not repeated herein.

As a preferred embodiment, the inductance 2 is formed by the excitation inductance of the primary side of the transformer.

The applicant considers that the excitation inductance exists on the primary side of the transformer and can resonate with the equivalent gate capacitance of the switching tube 3, so that the excitation inductance in the transformer can be reused, the cost is saved, and the circuit structure is simplified.

The adjustment of the driving signal of the switching tube 3 can be performed by selecting the magnetic core of the transformer with a suitable air gap so that the inductance of the excitation inductance corresponds to the dead time in the ac control signal.

As a preferred embodiment, the transformer is a planar transformer or a wound transformer.

The transformer in this embodiment may be, but is not limited to, a planar transformer or a wound-rotor transformer, the planar transformer or the wound-rotor transformer may not only implement the functions of transmitting and isolating the ac control signal, but also have the characteristics of a high frequency, a small height and a high operating frequency, and the wound-rotor transformer may also have the characteristic of a high window utilization rate, and may be selected based on its own needs.

As a preferred embodiment, the switch tube 3 is a MOS (Metal Oxide Semiconductor field effect transistor).

The applicant considers that the MOS transistor is controlled by a voltage driving signal, and therefore, the switching transistor 3 in the present application is a MOS transistor, and the switching transistor 3 can be driven by an ac control signal.

In addition, the MOS tube also has the characteristics of low power consumption and stable performance.

It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.