Half-bridge LLC charger driving circuit with wide output voltage range

Abstract

The invention discloses a wide-output-voltage-range half-bridge LLC charger driving circuit, and the circuit comprises a half-bridge circuit which comprises an upper tube driving circuit and a lower tube driving circuit which are connected in a totem-pole manner; and the independent power supply is connected with the upper tube driving circuit and the lower tube driving circuit through windings and supplies power to the first clamping circuit and the second clamping circuit. By designing a negative voltage clamping circuit, negative voltage clamping is completed after a power supply IC is started and before PWM output, the active negative voltage clamping function is achieved, negative voltage is achieved and kept constant when Vcc supplies power, the voltage value can be changed according to requirements, noise interference is avoided, mistaken machine explosion is prevented, and the driving reliability and the product safety are improved; the independent power supply can realize electrical isolation, protect the main circuit from being influenced by the abnormal condition of the driving circuit, reduce the risk of system damage, and the power supply of the driving circuit can be independently designed and optimized according to needs, thereby realizing more efficient energy conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics and wireless charging, and in particular to a half-bridge LLC charger driving circuit with a wide output voltage range. Background Art

[0002] With the popularization and application of portable energy storage products, especially in the emergence and growth of new scenarios such as outdoor work, outdoor travel, and disaster relief, the demand for lithium batteries has also grown rapidly. The continuous breakthroughs in lithium battery technology, the continuous improvement of energy density, portability, light weight, convenience, and continuous power have further pushed up the growth of demand for portable products, and the corresponding demand for chargers has grown rapidly.

[0003] Energy conservation, emission reduction and energy efficiency requirements are constantly increasing, and competition in the charger market is intensifying. Faced with many pressures and challenges, the development and design of chargers are also put forward higher requirements, such as safety, reliability, high efficiency, small size, light weight, etc., which need to meet rigid requirements. The resonant half-bridge LLC topology adopts resonant soft switching technology, zero voltage / current switching (ZVS / ZCS), its inherent soft switching characteristics and simple circuits, and has a variety of DC / DC converter topology types. Its conversion efficiency is currently the highest power topology and is widely used. However, since the charger needs to design constant current CC and constant voltage CV working modes, the output voltage span is very large from the low battery voltage to the full battery charging stage. The LLC topology has a relatively narrow output gain range and a large change in output voltage during the charging process. This feature conflicts with the best application of LLC soft switching and will bring efficiency and reliability problems. Especially when the output voltage is relatively low, due to low gain, the LLC operating frequency will increase significantly, resulting in the LLC operating point being much greater than the resonant point frequency and unable to achieve ZCS. At the same time, due to the high operating frequency and short excitation time, the excitation inductance design is not considered The working state of balance will lead to hard switching problems, especially the hard switching noise interference during battery switching or voltage fluctuation will bring serious reliability problems, such as: the noise interference exceeds the gate turn-on threshold voltage Vth of the power switch, causing the upper and lower switches to malfunction and directly explode, especially the new device wide bandgap gallium nitride power tube in half-bridge applications, due to faster dV / dt and dI / dt interference, it is more likely to cause reliability problems and increase the difficulty of design; the drive circuit and the main circuit use the same power supply, when any of the two has an abnormal operation, it will affect the operation of the other circuit. At present, most of the driving negative voltage clamps on the market are passive, and can only passively generate negative voltage clamps under normal operation. The negative voltage clamp function can hardly be realized during the startup process and the light load interval Burst mode. Summary of the invention

[0004] Based on this, it is necessary to propose a half-bridge LLC charger drive circuit design with a wide output voltage range to address the above problems. This design does not affect the turn-on performance and establishes a constant negative voltage between the driver and the power device when shutting down. This can completely and effectively clamp the power tube in the shut-off state (the negative clamping voltage can be adjusted) to avoid the shoot-through phenomenon caused by false operation.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A half-bridge LLC charger driving circuit with a wide output voltage range, comprising:

[0007] A half-bridge circuit comprises an upper tube driving circuit and a lower tube driving circuit connected in a totem pole manner, wherein the upper tube driving circuit comprises a field effect tube Q1, a high-side driving switch and a first clamping circuit, wherein the first clamping circuit is connected between the high-side driving switch and the field effect tube Q1, and the lower tube driving circuit comprises a field effect tube Q2, a low-side driving switch and a second clamping circuit, wherein the second clamping circuit is connected between the low-side driving switch and the field effect tube Q2; a drain electrode D2 of the field effect tube Q2 is connected to a source electrode S1 of the field effect tube Q1, the first clamping circuit is connected to the source electrode S1 of the field effect tube Q1, and the second clamping circuit is connected to the source electrode S2 of the field effect tube Q2; and an independent power supply is connected to the upper tube driving circuit and the lower tube driving circuit by a winding to supply power to the first clamping circuit and the second clamping circuit.

[0008] In some embodiments, the first clamping circuit includes a capacitor C2 and a Zener diode ZD1 , and the capacitor C2 and the Zener diode ZD1 are connected in parallel.

[0009] In some embodiments, the second clamping circuit includes a capacitor C3 and a Zener diode ZD2, and the capacitor C3 and the Zener diode ZD2 are connected in parallel.

[0010] In some embodiments, the high-side drive switch is connected in parallel in the upper tube drive circuit, and the low-side drive switch is connected in parallel in the lower tube drive circuit.

[0011] In some embodiments, the upper tube driving circuit further includes a resistor R1, and the lower tube driving circuit further includes a resistor R2, and the resistor R1 and the resistor R2 work alternately.

[0012] In some embodiments, the voltage of the first clamping circuit and the second clamping circuit is -2.4V.

[0013] In some embodiments, the upper tube driving circuit is further connected in parallel with a capacitor C1, and the lower tube driving circuit is further connected in parallel with a capacitor C4.

[0014] In some embodiments, a resonant circuit is further included. The resonant circuit is connected in parallel to Q2 and is used to control the frequency of the half-bridge circuit.

[0015] In some embodiments, the resonant circuit further includes a resonant inductor Lr, an excitation inductor Lm and a resonant capacitor Cr, and the resonant inductor Lr, the excitation inductor Lm and the resonant capacitor Cr are connected in series.

[0016] In some embodiments, a diode D3 and a diode D4 are further included, wherein the diode D3 is connected in series in the upper tube driving circuit, and the diode D4 is connected in series in the lower tube driving circuit.

[0017] The present invention proposes a half-bridge LLC charger driving circuit design with a wide output voltage range and designs a clamping circuit. After the power IC is started, the negative voltage clamping is completed before the PWM output, thereby realizing the active negative voltage clamping function. When Vcc provides power, the negative voltage is realized and kept constant. The voltage value can be changed according to demand to avoid noise interference, prevent accidental explosion, and improve the driving reliability and product safety. The independent power supply can realize electrical isolation, protect the main circuit from the influence of abnormal conditions of the driving circuit, and reduce the risk of system damage. The power supply of the driving circuit can be independently designed and optimized according to needs to realize more efficient energy conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] in:

[0019] Figure 1 It is a schematic diagram of a half-bridge LLC charger driving circuit with a wide output voltage range according to the present invention;

[0020] Figure 2 It is a timing diagram of the half-bridge LLC charger driving circuit with wide output voltage range according to the present invention when Vcc is powered on to establish negative voltage clamping;

[0021] Figure 3 It is a voltage PWM waveform diagram displayed after the main control IC of the wide output voltage range half-bridge LLC charger driving circuit of the present invention is increased and amplified.

[0022] The symbols in the accompanying drawings are described as follows:

[0023] 1. Half-bridge circuit; 11. Upper tube driving circuit; 111. High-side driving switch; 112. First clamping circuit; 12. Lower tube driving circuit; 121. Low-side driving switch; 122. Second clamping circuit; 2. Independent power supply; 3. Resonant circuit. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "connected" to another element, it can be directly on another element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "left", "right", "upper end", "lower end", "top" and "bottom" used in this specification indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0025] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0026] In order to solve the problem in the prior art that the noise interference exceeds the gate turn-on threshold voltage Vth of the power switch, resulting in malfunction of the upper and lower switches and direct burnout, a half-bridge LLC charger drive circuit with a wide output voltage range is proposed.

[0027] The following will be combined with the attached Figure 1 to Figure 2 A half-bridge LLC charger driving circuit with a wide output voltage range provided by an embodiment of the present invention is described in detail.

[0028] See also Figure 1 , Figure 1 The present invention is a schematic diagram of a half-bridge LLC charger driving circuit with a wide output voltage range, a half-bridge LLC charger driving circuit with a wide output voltage range, comprising:

[0029] A half-bridge circuit 1 comprises an upper tube driving circuit 11 and a lower tube driving circuit 12 connected in a totem pole manner, wherein the upper tube driving circuit 11 comprises a field effect tube Q1, a high side driving switch 111 and a first clamping circuit 112, wherein the first clamping circuit 112 is connected between the high side driving switch 111 and the field effect tube Q1, and the lower tube driving circuit 12 comprises a field effect tube Q2, a low side driving switch 121 and a second clamping circuit 122, wherein the second clamping circuit 122 is connected between the low side driving switch 121 and the field effect tube Q2; a drain electrode D2 of the field effect tube Q2 is connected to a source electrode S1 of the field effect tube Q1, the first clamping circuit 112 is connected to the source electrode S1 of the field effect tube Q1, and the second clamping circuit 122 is connected to a source electrode S2 of the field effect tube Q2; and an independent power supply 2 is connected to the upper tube driving circuit 11 and the lower tube driving circuit 12 by a winding to supply power to the first clamping circuit 112 and the second clamping circuit 122.

[0030] Specifically, in the commonly used half-bridge resonant LLC upper and lower tube driving mode, the gate (G) and source (S) GS voltage of the MOSFET is 0V when it is turned off. When the MOS is interfered by noise, the instantaneous voltage may exceed the turn-on threshold voltage Vth, resulting in false turn-on and burning of the upper and lower tubes. The turn-on threshold voltage Vth of the MOSFET is determined by the silicon base and process, and its inherent properties cannot be changed. To improve the anti-interference ability of the circuit, the anti-interference ability can only be enhanced from the PCB Layout. However, no matter how the routing is optimized, the driver IC can only be clamped at 0V when it is turned off. If a negative voltage can be generated at the GS end of the MOS when it is turned off, it is equivalent to turning on the interference voltage of the MOS to exceed: the turn-on threshold voltage Vth+2.4V to make it conduct. In this way, there is no need to restrict the PCB routing requirements too much, and the anti-interference ability of false operation when the midpoint voltage of the half-bridge / full-bridge suddenly changes can be improved, which greatly improves the reliability of the product. There are obvious improvements in the sudden change of the mains voltage, the sudden change of the load voltage and current, the interference of electrostatic discharge, the interference of lightning strikes, etc. At the same time, because the space layout can be improved and reasonably used, the volume of the power supply can be reduced. It can also be applied to scenarios such as high-power converters and gallium nitride devices. The application principle is the same and the reliability of the product can be improved.

[0031] By changing the power supply mode of the driver IC and designing the circuit, the active negative voltage clamping function is cleverly realized, and the negative voltage is realized when Vcc provides power, and the negative voltage remains constant and adjustable. After the power IC is started, the negative voltage clamping is completed before the PWM output, avoiding failures caused by the fact that the negative voltage has not been established during the startup process or the power supply is working in the light load gap / burst mode. Therefore, this circuit realizes the active negative voltage clamping covering all working mode changes after the IC is powered on.

[0032] The benefits of independent power supply are: it can achieve electrical isolation between the drive circuit and the main circuit, reduce mutual interference, and improve the stability and reliability of the system; when the drive circuit encounters abnormal conditions such as overload and short circuit, the main circuit is not affected; the power supply of the drive circuit can be independently designed and optimized as needed to meet specific performance requirements.

[0033] In one embodiment, the first clamping circuit 112 includes a capacitor C2 and a Zener diode ZD1 , and the capacitor C2 and the Zener diode ZD1 are connected in parallel.

[0034] Specifically, in the half-bridge circuit 1, the upper tube driving circuit 11 and the lower tube driving circuit 12 work alternately. When the upper tube driving circuit 11 works, the voltage regulator diode ZD1 is used to stabilize the voltage of the upper tube driving circuit 11 to prevent the influence of voltage fluctuations. If the selected voltage regulator diode is 2.4V, when the charging voltage of the capacitor C2 reaches 2.4V, it will not continue to rise and maintain this voltage as a clamping voltage. To turn on the interference voltage of the MOS tube, it must exceed its threshold voltage of 2.4V before it can be turned on. This can reduce the requirements for PCB routing, improve the anti-interference ability of malfunction when the midpoint voltage of the full-bridge / half-bridge changes suddenly, and improve the reliability of the product.

[0035] In one embodiment, the second clamping circuit 122 includes a capacitor C3 and a Zener diode ZD2 , and the capacitor C3 and the Zener diode ZD2 are connected in parallel.

[0036] Specifically, when the upper tube driving circuit 11 is turned off, the lower tube driving circuit 12 starts working, and the voltage stabilizing diode ZD2 is used to stabilize the voltage of the lower tube driving circuit 12 to prevent the influence of voltage fluctuations. If the selected voltage stabilizing diode is 2.4V, when the charging voltage of the capacitor C3 reaches 2.4V, it will not continue to rise, and this voltage will be maintained as a clamping voltage. To turn on the interference voltage of the MOS tube, it must exceed its threshold voltage of 2.4V before it can be turned on. This can reduce the requirements for PCB routing, improve the anti-interference ability of malfunction when the midpoint voltage of the full-bridge / half-bridge changes suddenly, and improve the reliability of the product.

[0037] In one embodiment, the high-side drive switch 111 is connected in parallel in the upper tube drive circuit 11 , and the low-side drive switch 121 is connected in parallel in the lower tube drive circuit 12 .

[0038] Specifically, a pin of the high-side drive switch 111 is connected to the gate of Q1, which is used to control the voltage of Q1 and thus control the conduction of Q1. When PWM outputs a high-level pulse width signal, the Gate output current of the driver IC returns to the driver IC through Q1, C2 and the negative terminal of the IC. When PWM outputs a low-level pulse width signal, the Gate output voltage of the driver IC is turned off (short circuit), and the current flows from the negative terminal of the driver IC to C2 (discharge) to Q1 (Qg).

[0039] In one embodiment, the upper tube driving circuit 11 further includes a resistor R1 , and the lower tube driving circuit 12 further includes a resistor R2 , and the resistor R1 and the resistor R2 work alternately.

[0040] Specifically, the resistor R1 and the resistor R2 limit the current in the circuit to prevent overload and overheating, play a role in protecting the circuit, and work alternately in the upper tube driving circuit 11 and the lower tube driving circuit 12.

[0041] When powered on, in the upper tube driving circuit 11, the line Vcc1 is powered on, and the current actively charges C2 through R1. When the charging voltage of C2 reaches the Zener diode ZD1, the current stops rising and maintains the voltage. In the lower tube driving circuit 12, the line Vcc2 is powered on, and the current actively charges C3 through R2. When the charging voltage of C3 reaches the Zener diode ZD2, the current stops rising and maintains the voltage.

[0042] In one embodiment, the voltage of the first clamp circuit 112 and the second clamp circuit 122 is -2.4V.

[0043] Specifically, the threshold turn-on voltage of MOS is between 2.4V and 2.8V, which can be selected according to actual needs. The common voltage regulator diode is generally 2.4V. The voltage regulator diode determines that the voltage of the negative voltage clamp circuit is mostly 2.4V. Therefore, the threshold turn-on voltage of the MOS tube is usually 2.4V. In the off state, it will be disturbed by noise. The instantaneous voltage may exceed the threshold voltage and cause the MOS tube to be turned on by mistake. Therefore, the voltage of the first clamp circuit 112 and the second clamp circuit 122 is set to -2.4V. The voltage of the clamp circuit can be adjusted and can also be adjusted according to actual needs.

[0044] In one embodiment, the upper tube driving circuit 11 is further connected in parallel with a capacitor C1 , and the lower tube driving circuit 12 is further connected in parallel with a capacitor C4 .

[0045] Specifically, capacitors C1 and C4 can smooth the voltage by absorbing and releasing charges, thereby reducing voltage fluctuations, and can stabilize the voltage to a certain extent. When the circuit voltage decreases or the current changes, the capacitor releases the stored energy to keep the circuit voltage stable; in devices such as switching power supplies, capacitors can protect components and circuits; when the switching components are turned off, the capacitor absorbs and releases energy to reduce damage caused by overvoltage and current.

[0046] In one embodiment, a resonant circuit 3 is further included. The resonant circuit is connected in parallel to Q2 and is used to control the frequency of the half-bridge circuit 1 .

[0047] Specifically, the resonant circuit can be used for filtering, frequency selection, impedance transformation and interference suppression.

[0048] In one embodiment, the resonant circuit 3 further includes a resonant inductor Lr, an excitation inductor Lm and a resonant capacitor Cr, and the resonant inductor Lr, the excitation inductor Lm and the resonant capacitor Cr are connected in series.

[0049] Specifically, the resonant inductor Lr stores and releases energy, the resonant capacitor Cr isolates DC, filters and balances the transformer flux to prevent transformer saturation, the excitation inductor Lm, the resonant capacitor Cr and the resonant inductor Lr together form a resonant cavity, and the resonant capacitor Cr and the resonant inductor Lr work together to ensure that the current in the circuit flows in the form of a sine wave, realizing the periodic conversion of energy, thereby reducing switching losses and realizing soft switching technology.

[0050] In one embodiment, a diode D3 and a diode D4 are further included. The diode D3 is connected in series to the upper tube driving circuit 11 , and the diode D4 is connected in series to the lower tube driving circuit 12 .

[0051] Specifically, diode D3 and diode D4 are used for rectification, freewheeling and protection, converting AC power into DC power, ensuring that current can only flow from the positive electrode to the negative electrode, thereby providing a stable DC power supply; in the inductor of the switching power supply, they play a freewheeling role. When the switch is closed, the current in the inductor cannot change suddenly, which will generate a reverse electromotive force. The diode can provide a low-impedance path so that the current can continue to flow, thereby protecting other components in the circuit from damage; it can also be used to protect the circuit from voltage spikes and reverse voltages that damage the circuit, and ensure the stable operation of the circuit by limiting the peak value of the voltage.

[0052] Working principle description: please refer to Figure 2 and Figure 3 , Figure 2 It is a timing diagram of the half-bridge LLC charger driving circuit with wide output voltage range according to the present invention when Vcc is powered on to establish negative voltage clamping; Figure 3It is a voltage PWM waveform diagram displayed after the main control IC of the wide output voltage range half-bridge LLC charger driving circuit of the present invention is enlarged. When the power is turned on, the line Vcc is powered on first, and the current actively charges C2 through R1. ZD1 is a negative voltage clamping Zener diode. If the selected Zener diode is 2.4V, then when the charging voltage of C2 reaches 2.4V, it will not continue to rise and maintain this voltage. R1=10KΩ, C2=2.2uF, ZD1=2.4V, according to the charging constant, the time to be fully charged to 2.4V is about 4.5mS, that is, the 2.4V clamping voltage is established within 5mS of establishing Vcc when the power is turned on. When the main control IC and the driver IC meet the power-on conditions (generally at least 50mS or more), the PMW output signal is played. After 50mS, the circuit has completed the negative voltage clamping. Regardless of the working mode of the main control IC, the clamping circuit has been working and has been maintaining the clamping state. When PWM outputs a high-level pulse width signal, the Gate output current of the driver IC passes through Q1 (Qg), C2, and the negative end of the IC back to the driver IC. At this time, the opening drive voltage obtained by the MOSFET is: 12V-2.4V=9.6V, and the smooth opening of the MOS tube is not affected. When PWM outputs a low-level pulse width signal, the Gate output voltage of the driver IC is closed (short circuit). At this time, the current flows from the negative end of the driver IC, C2 (discharge), Q1 (Qg). At this time, the closing drive voltage obtained by the MOSFET is: 0V-2.4V=-2.4V. After the charge of Qg is released, C2 can quickly obtain charge replenishment through R1 to maintain the clamping voltage. Therefore, Q1 MOS is always clamped at -2.4V when it is closed to improve anti-interference and reliability.

[0053] The advantage of designing a clamping circuit is that after the power supply IC is started, the negative voltage clamping is completed before the PWM output, avoiding failures caused by the negative voltage not being established during the startup process or the power supply working in the light-load interval Burst mode. Therefore, this circuit covers all the working mode changes after the IC is powered on, realizes the active negative voltage clamping function, and realizes the negative voltage when Vcc provides power. The negative voltage remains constant and the voltage value can be changed according to demand to avoid noise interference, prevent accidental explosions, and improve the reliability of the drive and the safety of the product.

[0054] The benefits of independent power supply for drive lines mainly include the following aspects:

[0055] Electrical isolation: Independent power supply can achieve electrical isolation between the drive circuit and the main circuit, reduce mutual interference, and improve the stability and reliability of the system. Protect the main circuit: In some cases, the drive circuit may face abnormal conditions such as overload and short circuit. If an independent power supply is used, it is easier to protect the main circuit from these abnormal conditions and reduce the risk of system damage. Flexibility: Independent power supply allows the power supply of the drive circuit to be independently designed and optimized as needed to meet specific performance requirements. For example, the power supply voltage and current range can be adjusted according to the load characteristics to achieve more efficient energy conversion.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention is described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A half-bridge LLC charger drive circuit with a wide output voltage range, characterized in that: include: A half-bridge circuit, comprising an upper tube driving circuit and a lower tube driving circuit connected in a totem pole manner, wherein the upper tube driving circuit comprises a field effect tube Q1, a high-side driving switch and a first clamping circuit, wherein the first clamping circuit is connected between the high-side driving switch and the field effect tube Q1, and the lower tube driving circuit comprises a field effect tube Q2, a low-side driving switch and a second clamping circuit, wherein the second clamping circuit is connected between the low-side driving switch and the field effect tube Q2; The drain D2 of the field effect transistor Q2 is connected to the source S1 of the field effect transistor Q1, the first clamping circuit is connected to the source S1 of the field effect transistor Q1, and the second clamping circuit is connected to the source S2 of the field effect transistor Q2; An independent power supply is connected to the upper tube driving circuit and the lower tube driving circuit by a winding to supply power to the first clamping circuit and the second clamping circuit.

2. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 1, characterized in that: The first clamping circuit includes a capacitor C2 and a voltage stabilizing diode ZD1 , and the capacitor C2 and the voltage stabilizing diode ZD1 are connected in parallel.

3. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 1, characterized in that: The second clamping circuit includes a capacitor C3 and a voltage stabilizing diode ZD2, and the capacitor C3 and the voltage stabilizing diode ZD2 are connected in parallel.

4. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 1, characterized in that: The high-side drive switch is connected in parallel in the upper tube drive circuit, and the low-side drive switch is connected in parallel in the lower tube drive circuit.

5. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 4, characterized in that: The upper tube driving circuit further includes a resistor R1, and the lower tube driving circuit further includes a resistor R2, and the resistor R1 and the resistor R2 work alternately.

6. A wide output voltage range half-bridge LLC charger drive circuit according to claim 1, characterized in that: The voltage of the first clamping circuit and the second clamping circuit is -2.4V.

7. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 1, characterized in that: The upper tube driving circuit is further connected in parallel with a capacitor C1 , and the lower tube driving circuit is further connected in parallel with a capacitor C4 .

8. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 1, characterized in that: It also includes a resonant circuit, which is connected in parallel to Q2 and is used to control the frequency of the half-bridge circuit.

9. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 8, characterized in that: The resonant circuit further includes a resonant inductor Lr, an excitation inductor Lm and a resonant capacitor Cr, and the resonant inductor Lr, the excitation inductor Lm and the resonant capacitor Cr are connected in series.

10. A half-bridge LLC charger driving circuit with a wide output voltage range according to claim 1, characterized in that: It also includes a diode D3 and a diode D4, wherein the diode D3 is connected in series in the upper tube driving circuit, and the diode D4 is connected in series in the lower tube driving circuit.

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