A bootstrap circuit, integrated drive circuit and Buck converter

Abstract

The present application discloses a bootstrap circuit, an integrated drive circuit, and a Buck converter, which are used in the field of power electronics technology to solve the problem in the prior art that the bootstrap circuit cannot power the high-side drive module corresponding to the high-side switch tube in the converter with a wide duty cycle range. Specifically, when the first on-off control module connects the main energy storage module to the external first power supply, the main energy storage module is charged by the external first power supply, and when the third on-off control module connects the main energy storage module to the auxiliary energy storage module, the main energy storage module is charged by the auxiliary energy storage module; when the second on-off control module is connected, the auxiliary energy storage module is charged by the external second power supply. By setting up the auxiliary energy storage module to replenish energy for the main energy storage module, the main energy storage module can generate sufficient voltage to the high-side drive module, and the bootstrap circuit can power the high-side drive module corresponding to the high-side switch tube of the wide-range duty cycle converter, and can support normal power supply with a 100% duty cycle.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a bootstrap circuit, an integrated drive circuit, and a Buck converter. Background Art

[0002] Switching converters are widely used in various consumer and industrial electronics fields and are gradually developing towards meeting a wide input voltage range. Existing switching converters typically use silicon-based NMOS transistors or gallium nitride high electron mobility transistors (GaN HEMTs) as high-side and low-side switches. Taking the existing wide-input-output-range step-down (Buck) switching converter as an example, to meet the wide input voltage range, the converter's duty cycle (D) variation range has increased significantly. Duty cycle D is the percentage of the high-side switch's on-time as a percentage of the duty cycle. Currently, step-down (Buck) circuits using silicon-based NMOS devices as high-side switches typically generate the higher voltage required to drive the high-side switch through a bootstrap circuit (Boostrap), consisting of a bootstrap capacitor CBOOT and a high-voltage diode DHV.

[0003] This bootstrap circuit relies on charging the bootstrap capacitor while the low-side switch is on but the high-side switch is off. This allows the bootstrap capacitor to generate the higher voltage required to drive the high-side switch. This results in a narrow duty cycle range for the circuit containing the high-side switch. When the duty cycle is high, the low-side switch's on-time is short, and the energy used to charge the capacitor during the high-side switch's off-time is less than the energy consumed by the driver circuit during its on-time. This results in the bootstrap circuit being unable to generate sufficient voltage to power the high-side driver module, preventing the high-side switch from remaining on for extended periods of its operating cycle. This can lead to output anomalies in the circuit containing the high-side switch. Summary of the Invention

[0004] The embodiments of the present application provide a bootstrap circuit, an integrated drive circuit and a Buck converter to solve the problem in the prior art that the bootstrap circuit cannot power the high-side drive module corresponding to the high-side switch tube in a converter with a wide duty cycle range.

[0005] The technical solutions provided in the embodiments of this application are as follows:

[0006] On the one hand, an embodiment of the present application provides a bootstrap circuit, comprising: a first on-off control module, a second on-off control module, a third on-off control module, a main energy storage module, and an auxiliary energy storage module;

[0007] The first input end of the main energy storage module is connected to the external first power supply via the first on-off control module, the first output end of the main energy storage module is connected to the high-voltage power supply end of the external high-side driver module, and the second output end of the main energy storage module is connected to the low-voltage power supply end of the external high-side driver module;

[0008] The first input terminal of the auxiliary energy storage module is connected to the external second power supply, the second input terminal of the auxiliary energy storage module is connected to the ground via the second on-off control module, and the first output terminal of the auxiliary energy storage module is connected to the second input terminal of the main energy storage module;

[0009] The control ends of the first on-off control module, the second on-off control module and the third on-off control module are respectively connected to the external control module;

[0010] The first on-off control module is used to connect the main energy storage module to the external first power supply when the external high-side driver module does not drive the high-side switch tube to turn on, and disconnect the main energy storage module from the external first power supply when the external high-side driver module drives the high-side switch tube to turn on;

[0011] The second on-off control module is configured to disconnect the auxiliary energy storage module from the ground when the third on-off control module connects the main energy storage module to the auxiliary energy storage module, and connect the auxiliary energy storage module to the ground when the third on-off control module disconnects the main energy storage module from the auxiliary energy storage module;

[0012] The third on-off control module is configured to connect or disconnect the main energy storage module and the auxiliary energy storage module according to a preset on-off rule when the external high-side driver module drives the high-side switch tube to conduct. The on-off rule is configured to connect or disconnect the main energy storage module and the auxiliary energy storage module according to a preset on-off rule when the duty cycle of the high-side switch tube exceeds a preset threshold value. The on-off rule is configured to connect the main energy storage module and the auxiliary energy storage module multiple times according to a preset on-time within the on-time of the high-side switch tube, and disconnect the main energy storage module and the auxiliary energy storage module when the auxiliary energy storage module completes discharge.

[0013] The main energy storage module is configured to be charged through the external first power supply when the first on-off control module connects the main energy storage module to the external first power supply. The main energy storage module is also configured to be charged through the auxiliary energy storage module when the third on-off control module connects the main energy storage module to the auxiliary energy storage module. The auxiliary energy storage module is configured to be charged through the external second power supply when the second on-off control module connects the auxiliary energy storage module to the ground. The auxiliary energy storage module is also configured to discharge energy into the auxiliary energy storage module when the third on-off control module connects the main energy storage module to the auxiliary energy storage module.

[0014] In one possible implementation, the main energy storage module includes: a low-voltage capacitor;

[0015] The first end of the low-voltage capacitor is respectively connected to the first end of the first on-off control module, the first end of the third on-off control module and the high-voltage power supply end of the external high-side driver module, and the second end of the low-voltage capacitor is respectively connected to the second end of the third on-off control module and the low-voltage power supply end of the external high-side driver module;

[0016] The auxiliary energy storage module includes: high-voltage capacitor;

[0017] The first end of the high-voltage capacitor is connected to the third end of the third on-off control module and the external second power supply respectively, and the second end of the high-voltage capacitor is connected to the first end of the second on-off control module and the fourth end of the third on-off control module respectively.

[0018] In a possible implementation, the third on-off control module includes: a first MOS transistor and a second MOS transistor;

[0019] The input end of the first MOS transistor is connected to the first end of the high-voltage capacitor, the output end of the first MOS transistor is connected to the first end of the low-voltage capacitor, and the control end of the first MOS transistor is connected to the external control module;

[0020] The input end of the second MOS tube is connected to the second end of the low-voltage capacitor, the output end of the second MOS tube is connected to the second end of the high-voltage capacitor, and the control end of the second MOS tube is connected to the external control module.

[0021] In a possible implementation, the third on-off control module further includes: a first diode and a second diode;

[0022] The first diode is provided between the input terminal of the first MOS tube and the first terminal of the high-voltage capacitor, and the conduction direction of the first diode is opposite to the conduction direction of the body diode of the first MOS tube;

[0023] The second diode is arranged between the input end of the second MOS tube and the second end of the low-voltage capacitor. The conduction direction of the second diode is opposite to the conduction direction of the body diode of the second MOS tube.

[0024] In a possible implementation, the first on-off control module includes: a third MOS transistor and a fourth MOS transistor;

[0025] The drain of the third MOS tube is connected to the external first power supply, the source of the third MOS tube is connected to the source of the fourth MOS tube, and the gate of the third MOS tube is connected to the gate of the fourth MOS tube and the external control module respectively;

[0026] The drain of the fourth MOS tube is connected to the first input terminal of the main energy storage module.

[0027] In a possible implementation, the bootstrap circuit further includes: a third diode;

[0028] The anode of the third diode is connected to the external second power supply, and the cathode of the third diode is connected to the first input end of the auxiliary energy storage module.

[0029] In a possible implementation, the bootstrap circuit further includes: a control signal generating module;

[0030] The input end of the control signal generating module is connected to the external control module, the output end of the control signal generating module is connected to the second on-off control module, and the power supply end of the control signal generating module is connected to the external first power supply; the control signal generating module is used to convert the control signal input from the external control module into a control signal of the second on-off control module.

[0031] In a possible implementation, the control signal generating module includes: a first current source, a second current source, a first switch, a second switch, a first capacitor, a Schmitt trigger, and an AND gate;

[0032] The positive terminal of the first current source is connected to the external first power supply, and the negative terminal of the first current source is connected to the first terminal of the first switch; the second terminal of the first switch is connected to the first terminal of the second switch and the first terminal of the first capacitor respectively; the second terminal of the second switch is connected to the positive terminal of the second current source; the negative terminal of the second current source is connected to ground; and the second terminal of the first capacitor is connected to ground;

[0033] The control end of the first switch and the control end of the second switch are connected to the control module;

[0034] The input terminal of the Schmitt trigger is connected to the second terminal of the first capacitor, and the output terminal of the Schmitt trigger is connected to the first input terminal of the AND gate;

[0035] The second input end of the AND gate is connected to the external control module, and the output end of the AND gate is connected to the control end of the second on-off control module.

[0036] On the other hand, an embodiment of the present application provides an integrated driving circuit, comprising: a high-side driving module, a low-side driving module, and the above-mentioned bootstrap circuit provided in an embodiment of the present application;

[0037] The high-voltage power supply end of the high-side driving module is connected to the high-voltage output end of the bootstrap circuit, the low-voltage power supply end of the high-side driving module is connected to the high-voltage output end of the bootstrap circuit, the input end of the high-side driving module is connected to the external control module, and the output end of the high-side driving module is connected to the gate of the external high-side switching tube;

[0038] The high-voltage power supply end of the low-side driving module is connected to the external first power supply, the low-voltage power supply end of the low-side driving module is connected to the ground, the input end of the low-side driving module is connected to the external control module, and the output end of the low-side driving module is connected to the gate of the external low-side switching tube.

[0039] On the other hand, an embodiment of the present application provides a Buck converter, comprising: a high-side switch tube, a low-side switch tube, an inductor, a capacitor, a control module, and the above-mentioned integrated drive circuit provided in an embodiment of the present application;

[0040] The gate of the high-side switch is connected to the first drive signal output terminal of the integrated drive circuit, the drain of the high-side switch is connected to the external second power supply, and the source of the high-side switch is respectively connected to the drain of the low-side switch, the voltage output terminal of the integrated drive circuit, and the first end of the inductor;

[0041] The gate of the low-side switch tube is connected to the second drive signal output terminal of the integrated drive circuit, and the source of the low-side switch tube is connected to the ground;

[0042] The second end of the inductor is connected to the first end of the capacitor and the first end of the external load respectively; the second end of the capacitor is connected to the ground; the second end of the external load is connected to the ground; and the control module is connected to the integrated drive circuit.

[0043] The beneficial effects of the embodiments of the present application are as follows:

[0044] In an embodiment of the present application, when the external high-side driver module does not drive the high-side switch tube to turn on, the main energy storage module charges and stores energy through the external first power supply. When the external high-side driver module drives the high-side switch tube to turn on, the auxiliary energy storage module is provided to replenish energy to the main energy storage module. That is, when the duty cycle of the converter where the high-side switch tube is located is high and exceeds a preset duty cycle threshold, the auxiliary energy storage module is automatically turned on. At this time, the energy storage of the main energy storage module does not depend on the conduction time of the low-side switch tube in the external circuit. Even if the duty cycle of the converter where the low-side switch tube and the high-side switch tube are located reaches 100%, the main energy storage module can generate sufficient voltage to the high-side driver module that drives the high-side switch tube. That is, the bootstrap circuit can power the high-side driver module corresponding to the high-side switch tube in the converter with a wide duty cycle range, and support the normal power supply of the high-side driver module corresponding to the high-side switch tube in the converter with a 100% duty cycle.

[0045] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description or be understood by practicing the present application. The purposes and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0047] Figure 1 Schematic diagram of the circuit structure of the bootstrap circuit in the prior art;

[0048] Figure 2 This is a schematic diagram of a first circuit structure of a bootstrap circuit in an embodiment of the present application;

[0049] Figure 3 This is a schematic diagram of a second circuit structure of the bootstrap circuit in an embodiment of the present application;

[0050] Figure 4 This is a working waveform diagram of the bootstrap circuit in state 1 in an embodiment of the present application;

[0051] Figure 5 Schematic diagram of the working mode of the bootstrap circuit in state 1 in an embodiment of the present application;

[0052] Figure 6 This is a working waveform diagram of the bootstrap circuit in state 2 in an embodiment of the present application;

[0053] Figure 7 Schematic diagram of the working mode of the bootstrap circuit in state 2 in an embodiment of the present application;

[0054] Figure 8 This is a working waveform diagram of the bootstrap circuit in state three in an embodiment of the present application;

[0055] Figure 9 Schematic diagram of the working mode of the bootstrap circuit in state three in an embodiment of the present application;

[0056] Figure 10 Schematic diagram of the third circuit structure of the bootstrap circuit in the embodiment of the present application;

[0057] Figure 11 Schematic diagram of the circuit structure of the integrated driving circuit in the embodiment of the present application;

[0058] Figure 12 Schematic diagram of the circuit structure of the Buck converter in the embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and beneficial effects of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0060] It should be noted that the terms "first," "second," etc., mentioned in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that such terms are interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0061] First, the application scenarios and design concepts of the embodiments of the present application are briefly introduced.

[0062] Currently, switching converters are widely used in various consumer and industrial electronics fields, and are gradually developing towards meeting the requirements of a wide input voltage range. Taking the existing wide input and output range step-down (Buck) switching converter as an example, in order to meet the wide input voltage range, the converter's duty cycle D variation range has been significantly increased. Figure 1 As shown in FIG, the bootstrap circuit (Boostrap) is composed of a bootstrap capacitor CBOOT and a high-voltage diode DHV. Figure 1 The bootstrap circuit includes a diode DHV, a bootstrap capacitor C, a high-side switch QH, a low-side switch QL, a high-side driver, a low-side driver, an inductor L, an output filter capacitor Co, and an output load resistor RL. The bootstrap capacitor in this bootstrap circuit needs to be charged for a period of time in each cycle, which will limit the duty cycle range that the converter can achieve. This is because the normal operation of the Buck circuit in which the high-side switch is driven in a bootstrap manner depends on charging the bootstrap capacitor during the period when the low-side switch is turned on but the high-side switch is turned off. Once the input voltage is close to the output and the maintenance time is long, that is, the on-time of the low-side switch is short, the energy charged to the capacitor during the off-time period of the high-side switch will be less than the energy consumed by the driving circuit during the on-time period, and the voltage V on the bootstrap capacitor will increase. BST will continue to decrease, causing V OUT Furthermore, GaN power devices lack the body diode reverse recovery process of traditional MOSFETs, enabling rapid turn-off and are therefore often used in high-frequency applications. However, at high frequencies, the low-side switch's on-time is relatively short, making it more difficult to charge the bootstrap capacitor. Consequently, widening the duty cycle range of the high-side switch is more difficult.

[0063] To this end, in an embodiment of the present application, when the external high-side driver module does not drive the high-side switch tube to turn on, the main energy storage module charges and stores energy through the external first power supply. When the external high-side driver module drives the high-side switch tube to turn on, the auxiliary energy storage module is provided to replenish energy to the main energy storage module. That is, when the duty cycle of the converter where the high-side switch tube is located is high and exceeds a preset duty cycle threshold, the auxiliary energy storage module is automatically turned on. At this time, the energy storage of the main energy storage module is not dependent on the conduction time of the low-side switch tube in the external circuit. Even if the duty cycle of the converter where the low-side switch tube and the high-side switch tube are located reaches 100%, the main energy storage module can generate sufficient voltage to the high-side driver module that drives the high-side switch tube. That is, the bootstrap circuit can power the high-side driver module corresponding to the high-side switch tube in the converter with a wide duty cycle range, and support the normal power supply of the high-side driver module corresponding to the high-side switch tube in the converter with a 100% duty cycle. Moreover, by providing an auxiliary energy storage module to supplement energy for the main energy storage module, the size of the bootstrap capacitor in the circuit can be reduced, making it easier to integrate the bootstrap circuit with the external high-side drive module and low-side drive module on the same chip.

[0064] After introducing the application scenarios and design concepts of the embodiments of the present application, the technical solutions provided by the embodiments of the present application are described in detail below.

[0065] The embodiment of the present application provides a bootstrap circuit 100, see Figure 2 As shown, the bootstrap circuit 100 includes: a first on-off control module 110, a second on-off control module 120, a third on-off control module 130, a main energy storage module 140 and an auxiliary energy storage module 150;

[0066] The first input terminal of the main energy storage module 140 is connected to the external first power supply VDD via the first on-off control module 110, the first output terminal of the main energy storage module 140 is connected to the high-voltage power supply terminal of the external high-side driver module, and the second output terminal of the main energy storage module 140 is connected to the low-voltage power supply terminal of the external high-side driver module;

[0067] The first input terminal of the auxiliary energy storage module 150 is connected to the external second power supply VIN, the second input terminal of the auxiliary energy storage module 150 is connected to the ground via the second on-off control module 120, and the first output terminal of the auxiliary energy storage module 150 is connected to the second input terminal of the main energy storage module 140;

[0068] The control terminals of the first on-off control module 110 , the second on-off control module 120 and the third on-off control module 130 are respectively connected to the external control module;

[0069] The first on-off control module 110 is used to connect the main energy storage module 140 to the external first power supply VDD when the external high-side driver module does not drive the high-side switch tube to turn on, and disconnect the main energy storage module 140 from the external first power supply VDD when the external high-side driver module drives the high-side switch tube to turn on;

[0070] The second on-off control module 120 is configured to disconnect the auxiliary energy storage module 150 from the ground when the third on-off control module 130 connects the main energy storage module 140 and the auxiliary energy storage module 150, and to connect and disconnect the auxiliary energy storage module 150 from the ground when the third on-off control module 130 disconnects the main energy storage module 140 and the auxiliary energy storage module 150;

[0071] The third on-off control module 130 is configured to connect or disconnect the main energy storage module 140 and the auxiliary energy storage module 150 according to a preset on-off rule when the external high-side driver module drives the high-side switch tube to turn on. The on-off rule is that when the duty cycle of the high-side switch tube exceeds a preset threshold, the main energy storage module 140 and the auxiliary energy storage module 150 are connected multiple times according to a preset on-time within the on-time of the high-side switch tube, and the connection between the energy storage module 140 and the auxiliary energy storage module 150 is disconnected when the auxiliary energy storage module 150 completes discharging.

[0072] The main energy storage module 140 is configured to be charged by the external first power supply VDD when the first on-off control module 110 connects the main energy storage module 140 to the external first power supply VDD. The main energy storage module 140 is also configured to be charged by the auxiliary energy storage module 150 when the third on-off control module 130 connects the main energy storage module 140 to the auxiliary energy storage module 150.

[0073] The auxiliary energy storage module 150 is used to charge through the external second power supply VIN when the second on-off control module 120 connects the auxiliary energy storage module 150 to the ground; the auxiliary energy storage module 150 is also used to discharge to the auxiliary energy storage module 150 when the third on-off control module 130 connects the main energy storage module 140 to the auxiliary energy storage module 150.

[0074] exist Figure 2In the illustrated bootstrap circuit 100, the path from the external first power supply VDD via the first on / off control module 110 to the main energy storage module 140 is the primary charging path. The path from the external second power supply VIN via the auxiliary energy storage module 150 and the second on / off control module 120 to ground is the auxiliary charging path. The path from the auxiliary energy storage module 150 to the main energy storage module 140 via the third on / off control module 130 is the auxiliary discharging path. The external first power supply VDD can be the high-voltage power supply for the external low-side driver module, typically 5V. The voltage of the external second power supply VIN is higher than that of the external first power supply VDD. The external second power supply VIN is typically the power supply that provides the input voltage for the circuit containing the high-voltage switch corresponding to the high-side driver module connected to the bootstrap circuit 100. The on-time of the external high-side switch complements the on-time of the low-side switch, and together, the on-time of the high-side switch constitutes a single operating cycle. The on-off rule is that when the duty cycle of the high-side switch exceeds a preset threshold, the connection between the main energy storage module 140 and the auxiliary energy storage module 150 is repeatedly connected within the high-side switch on-time, according to a preset on-time duration, and the connection between the energy storage module 140 and the auxiliary energy storage module 150 is disconnected when the auxiliary energy storage module 150 reaches the on-time duration. The on-time duration and the number of connections can be set based on the high-side switch on-time and the charge storage capacity of the main energy storage module 140. A shorter on-time duration and fewer on-times result in less additional charge provided by the auxiliary discharge path to the main energy storage module 140. A longer on-time duration and more on-times result in more additional charge provided by the auxiliary energy storage module 150 to the main energy storage module 140. A weaker charge storage capacity of the main energy storage module 140 requires more on-times and a longer on-time duration to ensure that the auxiliary energy storage module 150 provides sufficient charge to the main energy storage module 140. The auxiliary energy storage module 150 cannot be charged and discharged simultaneously. Therefore, when the third on-off control module 130 is off, the second on-off control module 120 is on; when the third on-off control module 130 is on, the second on-off control module 120 is off. When the first on-off control module 110 connects the main energy storage module 140 to the external first power supply VDD, the third on-off control module 130 disconnects the main energy storage module 140 from the auxiliary energy storage module 150. The external first power supply VDD charges the main energy storage module 140 via the main charging path. At this time, the first and second output terminals of the main energy storage module 140 have no voltage output, and the bootstrap circuit 100 does not supply power to the external high-side driver module, corresponding to the high-side switch being off. Simultaneously, the second on-off control module 120 connects the auxiliary energy storage module 150 to ground, and the external second power supply VIN charges the auxiliary energy storage module 150 via the auxiliary charging path.When the first on-off control module 110 disconnects the main energy storage module 140 from the external first power supply VDD, a voltage is output from the first output terminal and the second output terminal of the main energy storage module 140, and the bootstrap circuit 100 starts to supply power to the external high-side driver module, corresponding to the state in which the high-side switch tube is turned on. During this process, the second on-off control module 120 first maintains the state in which the auxiliary energy storage module 150 is connected to the ground, so that the external second power supply VIN continues to charge the auxiliary energy storage module 150 through the auxiliary charging path. When the charge in the main energy storage module 140 is insufficient to power the high-side driver module, the second on-off control module 120 disconnects the auxiliary energy storage module 150 from the ground, and the third on-off control module 130 connects the main energy storage module 140 and the auxiliary energy storage module 150. The auxiliary energy storage module 150 charges the main energy storage module 140 through the auxiliary discharge path, so that the main energy storage module 140 obtains sufficient charge and powers the high-side driver module.

[0075] In practical applications, when the switching converter operates at a 100% duty cycle, the high-side switch is continuously on, and the high-side driver module that drives the high-side switch needs to be continuously powered. Simultaneously, the auxiliary energy storage module 150 in the bootstrap circuit 100 continuously provides additional charge to the main energy storage module 140 via the auxiliary discharge path, allowing the main energy storage module 140 to continuously power the high-side driver module. When the duty cycle of the high-side switch exceeds a preset threshold, corresponding to the switching converter operating at a higher duty cycle (e.g., 80%-100%), the auxiliary energy storage module 150 in the bootstrap circuit 100 continuously provides additional charge to the main energy storage module 140 via the auxiliary discharge path, allowing the main energy storage module 140 to power the high-side driver module when the high-side switch is on. When the duty cycle of the high-side switch tube does not exceed the preset threshold, corresponding to the switching converter operating at a lower duty cycle (for example, below 80%), the auxiliary energy storage module 150 in the bootstrap circuit 100 does not charge or discharge, and the main energy storage module 140 supplies power to the high-side driver module when the high-side switch tube is turned on, so as to reduce the loss caused by charging and discharging of the auxiliary energy storage module.

[0076] In specific implementation, the main energy storage module 140 in the bootstrap circuit has a variety of structures to achieve its functions, see Figure 3 As shown, the main energy storage module 140 may include: a low voltage capacitor C BOOT ;

[0077] Low voltage capacitor C BOOT The first end of the first on-off control module 110, the first end of the third on-off control module 130 and the high-voltage power supply end of the external high-side drive module are respectively connected, and the low-voltage capacitor C BOOT The second end of is respectively connected to the second end of the third on-off control module 130 and the low-voltage power supply end of the external high-side drive module;

[0078] The auxiliary energy storage module 150 may include: a high voltage capacitor C SUPPLY ;

[0079] High voltage capacitor C SUPPLY The first end of the third on-off control module 130 and the external second power supply VIN are connected respectively, and the high-voltage capacitor C SUPPLY The second end of the on-off control module 120 is connected to the first end of the second on-off control module 120 and the fourth end of the third on-off control module 130 respectively.

[0080] exist Figure 3 In the bootstrap circuit shown, since the voltage of the external first power supply VDD is relatively low, generally 5V, in order to be charged by the external first power supply VDD, the main energy storage module 140 can use a low-voltage capacitor C BOOT Since the external second power supply VIN is the power supply voltage of the converter where the high-side switch tube is located, which is relatively high (for example, the voltage range of the external second power supply VIN can be 36-40V), in order to charge through the external second power supply VIN, the main energy storage module 140 can use a high-voltage capacitor C SUPPLY During the high-side switch conduction phase, the high-voltage capacitor C SUPPLY Give the low voltage capacitor C BOOT Discharge to replenish the low voltage capacitor C BOOT The charge on the capacitor C is directly supplied to the high voltage capacitor C through the external second power supply VIN with a higher voltage. SUPPLY Charging, set the capacitance value to a smaller C SUPPLY Capacitance can get higher V SUPPLY and sufficient charge to achieve C BOOT Rapid discharge. Compared with the prior art where a larger bootstrap capacitor is set to maintain the bootstrap voltage V BST Compared with the solution of CMOS, it is beneficial to reduce the size of on-chip capacitors.

[0081] In specific implementation, the third on-off control module 130 in the bootstrap circuit has a variety of structures to achieve its functions, see Figure 3 As shown, the third on-off control module 130 at least includes: a first MOS transistor Q1 and a second MOS transistor Q2;

[0082] The input terminal of the first MOS tube Q1 is connected to the high voltage capacitor C SUPPLY The first end of the first MOS tube Q1 is connected to the low-voltage capacitor C BOOT The first end of the first MOS tube Q1 is connected to the external control module;

[0083] The input end of the second MOS tube Q2 is connected to the low voltage capacitor C BOOT The second end of the second MOS tube Q2 is connected to the high-voltage capacitor C SUPPLYThe second end of the second MOS tube Q2 is connected to the external control module.

[0084] exist Figure 3 In the bootstrap circuit shown, the first MOS transistor Q1 and the second MOS transistor Q2 can be selected as NMOS transistors or PMOS transistors. The types of the first MOS transistor Q1 and the second MOS transistor Q2 can be the same or different. What needs to be satisfied is that the input and output terminals of the first MOS transistor Q1 and the second MOS transistor Q2 are connected to the high-voltage capacitor C SUPPLY and low voltage capacitor C BOOT The connection method forms a high voltage capacitor C SUPPLY Starting from the first end, it passes through the first MOS tube Q1, the low-voltage capacitor C BOOT First terminal, low voltage capacitor C BOOT After the second end and the second MOS tube Q2, it returns to the high-voltage capacitor C SUPPLY The second end of this auxiliary discharge path is used to achieve the high voltage capacitor C SUPPLY For low voltage capacitor C BOOT The first MOS tube Q1 and the second MOS tube Q2 are turned on or off at the same time.

[0085] In specific implementation, the third on-off control module 130 in the bootstrap circuit has a variety of structures to achieve its functions, see Figure 3 As shown, the third on-off control module 130 may further include: a first diode D1 and a second diode D2;

[0086] The first diode D1 is set between the input end of the first MOS tube Q1 and the high-voltage capacitor C SUPPLY Between the first ends of the first diode D1 and the first MOS transistor Q1, the conduction direction of the first diode D1 is opposite to the conduction direction of the body diode of the first MOS transistor Q1;

[0087] The second diode D2 is set between the input end of the second MOS tube Q2 and the low voltage capacitor C BOOT The conduction direction of the second diode D2 is opposite to the conduction direction of the body diode of the second MOS transistor Q2.

[0088] exist Figure 3 In the bootstrap circuit shown in FIG, when the first MOS transistor Q1 and the second MOS transistor Q2 are turned off, the first diode D1 and the body diode of the first MOS transistor Q1 form a back-to-back diode, and the second diode D2 and the body diode of the second MOS transistor Q2 form a back-to-back diode, which can effectively prevent the high-voltage capacitor C from being blocked when the first MOS transistor Q1 and the second MOS transistor Q2 are turned off. SUPPLY With low voltage capacitor C BOOT The charge transfer between the first MOS tube Q1 and the second MOS tube Q2 avoids shutting off the high-voltage capacitor C SUPPLY With low voltage capacitor CBOOT between charge and discharge.

[0089] In specific implementation, the first on-off control module 110 in the bootstrap circuit has a variety of structures to achieve its functions, see Figure 3 As shown, the first on-off control module 110 may include: a third MOS transistor Q3 and a fourth MOS transistor Q4;

[0090] The drain of the third MOS transistor Q3 is connected to the external first power supply VDD, the source of the third MOS transistor Q3 is connected to the source of the fourth MOS transistor Q4, and the gate of the third MOS transistor Q3 is connected to the gate of the fourth MOS transistor Q4 and the external control module respectively;

[0091] The drain of the fourth MOS transistor Q4 is connected to the first input terminal of the main energy storage module 140 .

[0092] exist Figure 3 In the bootstrap circuit shown, the third MOS transistor Q3 and the fourth MOS transistor Q4 are NMOS transistors, and the third MOS transistor Q3 and the fourth MOS transistor Q4 are connected in series back-to-back. The third MOS transistor Q3 and the fourth MOS transistor Q4 form an active diode. The use of the third MOS transistor Q3 and the fourth MOS transistor Q4 to form an active diode instead of the high-voltage diode in the traditional solution reduces the conduction voltage drop of the first on-off control module 110. The low-voltage capacitor C BOOT A higher charging voltage can be obtained. Compared with the existing bootstrap circuit, the low voltage capacitor C BOOT A higher charging voltage can be obtained at the low voltage capacitor C BOOT Under the premise of providing constant energy, the low voltage capacitor C can be reduced BOOT size to reduce the circuit area and facilitate the integration of the bootstrap circuit.

[0093] In one possible implementation, the first on-off control module can also be composed of a low-voltage PMOS transistor and a high-voltage PMOS transistor connected in series. The source of the low-voltage PMOS transistor is connected to the external first power supply VDD, and the drain is connected to the drain of the high-voltage PMOS transistor; the source of the high-voltage PMOS transistor is connected to the first input terminal of the main energy storage module; the gates of the two PMOS transistors are connected to the external control module, wherein the control signal level of the low-voltage PMOS transistor is 0 / VDD, and the control signal level of the high-voltage PMOS transistor is VSSH / VDDH. Because the low-voltage PMOS transistor and the high-voltage PMOS transistor form a "back-to-back" body diode when turned off, the low-voltage PMOS transistor and the high-voltage PMOS transistor connected in series can be used as an active diode.

[0094] In specific implementation, the second on-off control module 120 in the bootstrap circuit has a variety of structures to achieve its functions, see Figure 3As shown, the second on-off control module 120 may include: a fifth MOS transistor Q5;

[0095] An input end of the fifth MOS transistor Q5 is connected to the auxiliary energy storage module 150 , an output end of the fifth MOS transistor Q5 is connected to the ground, and a control end of the fifth MOS transistor Q5 is connected to the external control module.

[0096] In practical applications, the fifth MOS transistor Q5 can be an NMOS transistor or a PMOS transistor. Figure 5 The figure shows the connection method of the fifth MOS transistor Q5 as an NMOS transistor. Specifically, when the fifth MOS transistor Q5 is an NMOS transistor, the drain of the fifth MOS transistor Q5 is connected to the auxiliary energy storage module 150, the source of the fifth MOS transistor Q5 is connected to ground, and the gate of the fifth MOS transistor Q5 is connected to the external control module. When the fifth MOS transistor Q5 is a PMOS transistor, the source of the fifth MOS transistor Q5 is connected to the auxiliary energy storage module 150, the drain of the fifth MOS transistor Q5 is connected to ground, and the gate of the fifth MOS transistor Q5 is connected to the external control module. Because the switching state of the fifth MOS transistor Q5 is opposite to that of the first MOS transistor Q1 and the second MOS transistor Q2, and the switching states of the first MOS transistor Q1 and the second MOS transistor Q2 are the same, the drive signal V of the fifth MOS transistor Q5 is adjusted by the control module. PWM_EX The duty cycle and frequency can achieve the high voltage capacitor C SUPPLY Adjustment of the charging and discharging process to achieve the high voltage capacitor C SUPPLY To the low voltage capacitor C BOOT Adjustment of the supplementary charge.

[0097] In one possible implementation, see Figure 3 As shown, the bootstrap circuit further includes: a third diode D3;

[0098] An anode of the third diode D3 is connected to the external second power source VIN, and a cathode of the third diode D3 is connected to the first input terminal of the auxiliary energy storage module 150 .

[0099] exist Figure 3 In the bootstrap circuit shown, the third diode D3 is used to prevent the high voltage capacitor C SUPPLY After being fully charged, the battery is discharged to the external second power supply VIN, and damage to the bootstrap circuit caused by reverse connection of the power supply can be avoided.

[0100] Next, Figure 3 Taking the bootstrap circuit shown in the figure as an example, the working state of the bootstrap circuit is described in detail. Figure 4-Figure 9 As shown, where △V CH The voltage difference across the high-voltage capacitor, △V CL is the voltage difference across the low-voltage capacitor, VCONTROL_2 is the driving signal of the fifth MOS tube Q5, V CONTROL_1 The driving signals of the third MOS transistor Q3 and the fourth MOS transistor Q4 are the driving signals of the first MOS transistor Q1 and the second MOS transistor Q2, and the driving signals of the first MOS transistor Q1 and the second MOS transistor Q2 are the inverted V CONTROL_2 , V GSH is the driving signal of the high-side switch tube. When the bootstrap circuit works in state 1, V CONTROL_2 is low level, V CONTROL_1 is high level, V GSH The high-side switch is turned off, the main charging path works, and the external first power supply VDD is supplied to the low-voltage capacitor C through the active diode composed of the third MOS tube Q3 and the fourth MOS tube Q4. BOOT The capacitor is charged until the low voltage capacitor C BOOT The voltage difference between VDDH and VSSH is △V CL Rising to V BST When the bootstrap circuit works in state 2, V CONTROL_2 The external second power supply VIN directly supplies the high voltage capacitor C to the high voltage capacitor C. SUPPLY The capacitor is charged until the high voltage capacitor C SUPPLY The voltage difference between VSH and VSL is △V CH Rising to V SUPPLY When the bootstrap circuit works in state three, V CONTROL_2 is low level, V CONTROL_1 is low level, V GSH The high-side switch is turned on, the auxiliary discharge path works, and the high-voltage capacitor C SUPPLY Discharge to the low voltage capacitor C BOOT Charge.

[0101] In one possible implementation, see Figure 10 As shown, the bootstrap circuit further includes: a control signal generating module 160;

[0102] The input end of the control signal generating module 160 is connected to the external control module, the output end of the control signal generating module 160 is connected to the second on-off control module 120, and the power supply end of the control signal generating module 160 is connected to the external first power supply VDD; the control signal generating module 160 is used to convert the control signal input from the external control module into a control signal of the second on-off control module 120.

[0103] exist Figure 10 In the bootstrap circuit shown, the signal that the control module can output is the driving signal V of the high-side switch tube GSH , the low-side switch drive signal V GSL And the driving signal V determined according to the on-time and the number of on-timesPWM_EX The signal input from the control module to the control signal generating module 160 may be the driving signal V of the high-side switch tube. GSH and / or the low-side switch drive signal V GSL The signal input from the control module to the control signal generating module 160 also includes a driving signal V PWM_EX The control signal generating module 160 can generate a high-side switch tube drive signal V GSH and / or the low-side switch drive signal V GSL Determine the duty cycle and when the duty cycle exceeds the preset duty cycle threshold, the drive signal V PWM_EX The PWM outputs a low level signal to the second on-off control module 120 , and outputs a low level signal to the second on-off control module 120 when the duty cycle does not exceed the preset duty cycle threshold.

[0104] For specific implementation, see Figure 10 As shown, the control signal generating module includes: a first current source I CHARGE , the second current source I SINK , a first switch S1, a second switch S2, a first capacitor C1, a Schmitt trigger and an AND gate;

[0105] The first current source I CHARGE The positive terminal of the first current source I CHARGE The negative end of the first switch S1 is connected to the first end of the first switch S1; the second end of the first switch S1 is connected to the first end of the second switch S2 and the first end of the first capacitor C1 respectively; the second end of the second switch S2 is connected to the second current source I SINK The positive terminal of the second current source I SINK The negative terminal of the first capacitor C1 is connected to the ground; the second terminal of the first capacitor C1 is connected to the ground;

[0106] The control end of the first switch S1 and the control end of the second switch S2 are connected to the control module;

[0107] An input terminal of the Schmitt trigger is connected to the second terminal of the first capacitor C1, and an output terminal of the Schmitt trigger is connected to the first input terminal of the AND gate;

[0108] The second input end of the AND gate is connected to the external control module, and the output end of the AND gate is connected to the control end of the second on-off control module.

[0109] exist Figure 10 In the bootstrap circuit shown, the high-side switch tube and the low-side switch tube are driven complementary. The signal input from the control module to the control signal generation module is the drive signal V of the high-side switch tube. GSH and the low-side switch drive signal V GSLWhen the control signal of the first switch S1 is the driving signal V of the high-side switch tube GSH The control signal of the second switch S2 is the driving signal V of the low-side switch tube. GSL The signal input from the control module to the control signal generation module is the drive signal V of the high-side switch tube. GSH , but does not input the driving signal V of the low-side switch tube GSL When the control signal of the first switch S1 is the driving signal V of the high-side switch tube GSH The control signal of the second switch S2 is the inverted high-side switch drive signal V GSH The signal input from the control module to the control signal generation module is the drive signal V of the low-side switch tube. GSL , but does not input the driving signal V of the high-side switch tube GSH When the control signal of the first switch S1 is the inverted driving signal V of the low-side switch tube, GSL The control signal of the second switch S2 is the driving signal V of the low-side switch tube. GSL The first current source I CHARGE and the second current source I SINK The output current is set according to a preset ratio, which is determined according to a preset duty cycle threshold. The control signal of the first switch S1 is the driving signal V of the high-side switch tube. GSH The control signal of the second switch S2 is the inverted high-side switch drive signal V GSH For example, the driving signal V GSH When the first switch S1 is high, the first current source I CHARGE The second switch S2 disconnects the second current source I SINK The connection with the first capacitor C1, the first current source I CHARGE Charge the first capacitor C1; when the driving signal V GSH When the first switch S1 is low, it disconnects the first current source I CHARGE The second switch S2 is connected to the first capacitor C1 and conducts the second current source I SINK The first capacitor C1 is connected to the first capacitor C1 through the second current source I SINK When the duty cycle of the converter exceeds the preset duty cycle threshold, the drive signal V GSH In each cycle, the high level time is longer and the low level time is shorter. Correspondingly, the charging time of the first capacitor C1 is longer and the discharging time is shorter. After a series of charging and discharging processes, the voltage value V C1 The voltage value V at the first terminal of the first capacitor C1 is stable near the external first power supply voltage VDD. C1When the voltage is stable near VDD, the EN_PWM_EX level input to the AND gate after Schmitt rectification is flipped to high, and the AND gate outputs the driving signal V PWM_EX to the control end of the second on-off control module, so that the second control module can PWM_EX The corresponding connection duration and number of connections control the auxiliary energy storage module 150 to charge and discharge.

[0110] In addition, based on the above embodiment, the present application also provides an integrated driving circuit 200, see Figure 11 As shown, the integrated driving circuit at least includes: a high-side driving module 210, a low-side driving module 220 and the above-mentioned bootstrap circuit 100 provided in the embodiment of the present application;

[0111] The high-voltage power supply terminal of the high-side driving module 210 is connected to the high-voltage output terminal of the bootstrap circuit 100, the low-voltage power supply terminal of the high-side driving module 210 is connected to the high-voltage output terminal of the bootstrap circuit 100, the input terminal of the high-side driving module 210 is connected to the external control module, and the output terminal of the high-side driving module is connected to the external high-side switch tube Q. H The gate connection;

[0112] The high voltage power supply terminal of the low side driving module 220 is connected to the external first power supply VDD, the low voltage power supply terminal of the low side driving module 220 is connected to the ground, the input terminal of the low side driving module 220 is connected to the external control module, and the output terminal of the low side driving module is connected to the external low side switch tube Q. L Gate connection.

[0113] In addition, based on the above embodiment, the present application also provides a Buck converter, see Figure 12 As shown, the Buck converter at least includes: a high-side switch tube Q H , low-side switch tube Q L , inductor L, capacitor C, control module and the above-mentioned integrated driving circuit 200 provided in the embodiment of the present application;

[0114] High-side switch Q H The gate of the integrated driving circuit 200 is connected to the first driving signal output terminal, and the high-side switch tube Q H The drain of the high-side switch Q is connected to the external second power supply VIN. H The source of the low-side switch Q L The drain of the integrated driving circuit 200 and the voltage output terminal are connected to the first end of the inductor L;

[0115] Low-side switch Q L The gate of the integrated driving circuit 200 is connected to the second driving signal output terminal, and the low-side switch tube Q L The source is connected to ground;

[0116] The second end of the inductor L is connected to the first end of the capacitor C and the external load R L The first end of the capacitor C is connected to the ground; the second end of the capacitor C is connected to the ground; the external load R L The second end is connected to the ground; the control module is connected to the integrated drive circuit 200.

[0117] It should be noted that although several units or subunits of the device are mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, depending on the embodiment of the application, the features and functions of two or more units described above can be embodied in a single unit. Conversely, the features and functions of a single unit described above can be further divided and embodied by multiple units.

[0118] Furthermore, although the operations of the method of the present application are described in a particular order in the accompanying drawings, this does not require or imply that the operations must be performed in this particular order, or that all illustrated operations must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0119] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0120] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application also intends to include such modifications and variations.

Claims

1. A bootstrap circuit, characterized in that: include: A first on-off control module, a second on-off control module, a third on-off control module, a main energy storage module and an auxiliary energy storage module; The first input end of the main energy storage module is connected to the external first power supply via the first on-off control module, the first output end of the main energy storage module is connected to the high-voltage power supply end of the external high-side driver module, and the second output end of the main energy storage module is connected to the low-voltage power supply end of the external high-side driver module; The first input end of the auxiliary energy storage module is connected to the external second power supply, the second input end of the auxiliary energy storage module is connected to the ground via the second on-off control module, and the first output end of the auxiliary energy storage module is connected to the second input end of the main energy storage module; The control ends of the first on-off control module, the second on-off control module and the third on-off control module are respectively connected to an external control module; The first on-off control module is configured to connect the main energy storage module to the external first power supply when the external high-side driver module does not drive the high-side switch tube to turn on, and disconnect the main energy storage module from the external first power supply when the external high-side driver module drives the high-side switch tube to turn on; The second on-off control module is configured to disconnect the auxiliary energy storage module from the ground when the third on-off control module connects the main energy storage module to the auxiliary energy storage module, and connect the auxiliary energy storage module to the ground when the third on-off control module disconnects the main energy storage module from the auxiliary energy storage module; The third on-off control module is configured to connect or disconnect the connection between the main energy storage module and the auxiliary energy storage module according to a preset on-off rule when the external high-side driver module drives the high-side switch tube to turn on; wherein the on-off rule is that when the duty cycle of the high-side switch tube exceeds a preset threshold, the connection between the main energy storage module and the auxiliary energy storage module is connected multiple times according to a preset on-time within the on-time of the high-side switch tube, and the connection between the main energy storage module and the auxiliary energy storage module is disconnected when the auxiliary energy storage module completes discharging; The main energy storage module is configured to be charged by the external first power supply when the first on-off control module connects the main energy storage module to the external first power supply; the main energy storage module is further configured to be charged by the auxiliary energy storage module when the third on-off control module connects the main energy storage module to the auxiliary energy storage module; the auxiliary energy storage module is configured to be charged by the external second power supply when the second on-off control module connects the auxiliary energy storage module to the ground; and the auxiliary energy storage module is further configured to discharge to the main energy storage module when the third on-off control module connects the main energy storage module to the auxiliary energy storage module; The main energy storage module includes: a low-voltage capacitor; the auxiliary energy storage module includes: a high-voltage capacitor; The third on-off control module includes: a first MOS transistor and a second MOS transistor; The input end of the first MOS transistor is connected to the first end of the high-voltage capacitor, the output end of the first MOS transistor is connected to the first end of the low-voltage capacitor, and the control end of the first MOS transistor is connected to an external control module; The input end of the second MOS transistor is connected to the second end of the low-voltage capacitor, the output end of the second MOS transistor is connected to the second end of the high-voltage capacitor, and the control end of the second MOS transistor is connected to the external control module.

2. The bootstrap circuit according to claim 1, wherein: The first end of the low-voltage capacitor is respectively connected to the first end of the first on-off control module, the first end of the third on-off control module and the high-voltage power supply end of the external high-side drive module, and the second end of the low-voltage capacitor is respectively connected to the second end of the third on-off control module and the low-voltage power supply end of the external high-side drive module; The first end of the high-voltage capacitor is connected to the third end of the third on-off control module and the external second power supply respectively, and the second end of the high-voltage capacitor is connected to the first end of the second on-off control module and the fourth end of the third on-off control module respectively.

3. The bootstrap circuit according to claim 1, wherein: The third on-off control module further includes: a first diode and a second diode; The first diode is provided between the input terminal of the first MOS transistor and the first terminal of the high-voltage capacitor, and the conduction direction of the first diode is opposite to the conduction direction of the body diode of the first MOS transistor; The second diode is arranged between the input end of the second MOS tube and the second end of the low-voltage capacitor, and the conduction direction of the second diode is opposite to the conduction direction of the body diode of the second MOS tube.

4. The bootstrap circuit according to claim 1, wherein: The first on-off control module includes: a third MOS transistor and a fourth MOS transistor; The drain of the third MOS transistor is connected to the external first power supply, the source of the third MOS transistor is connected to the source of the fourth MOS transistor, and the gate of the third MOS transistor is connected to the gate of the fourth MOS transistor and the external control module respectively; The drain of the fourth MOS tube is connected to the first input end of the main energy storage module.

5. The bootstrap circuit according to any one of claims 1 to 4, wherein: Also includes: The third diode; The anode of the third diode is connected to the external second power supply, and the cathode of the third diode is connected to the first input end of the auxiliary energy storage module.

6. The bootstrap circuit according to claim 5, wherein: Also includes: control signal generation module; The input end of the control signal generating module is connected to the external control module, the output end of the control signal generating module is connected to the second on-off control module, and the power supply end of the control signal generating module is connected to the external first power supply; the control signal generating module is used to convert the control signal input by the external control module into a control signal of the second on-off control module.

7. The bootstrap circuit according to claim 6, wherein: The control signal generating module includes: a first current source, a second current source, a first switch, a second switch, a first capacitor, a Schmitt trigger and an AND gate; The positive terminal of the first current source is connected to an external first power source, and the negative terminal of the first current source is connected to the first terminal of the first switch; the second terminal of the first switch is connected to the first terminal of the second switch and the first terminal of the first capacitor respectively; the second terminal of the second switch is connected to the positive terminal of the second current source; the negative terminal of the second current source is connected to ground; and the second terminal of the first capacitor is connected to ground; The control end of the first switch and the control end of the second switch are connected to the control module; The input end of the Schmitt trigger is connected to the second end of the first capacitor, and the output end of the Schmitt trigger is connected to the first input end of the AND gate; The second input end of the AND gate is connected to the external control module, and the output end of the AND gate is connected to the control end of the second on-off control module.

8. An integrated drive circuit, characterized in that: include: A high-side driver module, a low-side driver module, and a bootstrap circuit according to any one of claims 1 to 7; The high-voltage power supply end of the high-side driving module is connected to the high-voltage output end of the bootstrap circuit, the low-voltage power supply end of the high-side driving module is connected to the low-voltage output end of the bootstrap circuit, the input end of the high-side driving module is connected to the external control module, and the output end of the high-side driving module is connected to the gate of the external high-side switching tube; The high-voltage power supply end of the low-side driving module is connected to the external first power supply, the low-voltage power supply end of the low-side driving module is connected to the ground, the input end of the low-side driving module is connected to the external control module, and the output end of the low-side driving module is connected to the gate of the external low-side switching tube.

9. A Buck converter, characterized in that: include: A high-side switch tube, a low-side switch tube, an inductor, a capacitor, a control module, and an integrated drive circuit according to claim 8; The gate of the high-side switch is connected to the first drive signal output terminal of the integrated drive circuit, the drain of the high-side switch is connected to an external second power supply, and the source of the high-side switch is connected to the drain of the low-side switch, the voltage output terminal of the integrated drive circuit, and the first end of the inductor respectively; The gate of the low-side switch tube is connected to the second drive signal output terminal of the integrated drive circuit, and the source of the low-side switch tube is connected to the ground; The second end of the inductor is connected to the first end of the capacitor and the first end of the external load respectively; the second end of the capacitor is connected to the ground; the second end of the external load is connected to the ground; The control module is connected to the integrated drive circuit.

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