Bootstrap drive circuit and half-bridge circuit

Abstract

The utility model provides a bootstrap driving circuit and a half-bridge circuit, and relates to the technical field of semiconductors, and the bootstrap driving circuit comprises an independent power supply, an upper bridge arm tube, a lower bridge arm tube, an upper bridge arm bootstrap module, a lower bridge arm bootstrap module, an upper bridge arm negative voltage module and a lower bridge arm negative voltage module. According to the technical scheme provided by the invention, the lower bridge arm negative voltage module is charged through the loop formed by the independent power supply and the lower bridge arm negative voltage module before the lower bridge arm tube is switched on, and then voltage is established. When the lower bridge arm tube is turned on, the upper bridge arm bootstrap module charges the capacitor through a loop formed by the independent power supply, the upper bridge arm bootstrap module, the anti-reverse diode, the lower bridge arm tube and the lower bridge arm negative voltage module to establish voltage, so that stable negative voltage is provided for the upper bridge arm tube and the lower bridge arm tube, and stable turn-off of the upper bridge arm tube and the lower bridge arm tube can be guaranteed. The reliability and the stability of the bootstrap driving circuit can be improved.

Description

Technical Field

[0001] This application belongs to the field of semiconductor technology, and in particular relates to a bootstrap driving circuit and a half-bridge circuit. Background Technology

[0002] A bootstrap circuit, also known as a boost circuit, uses electronic components such as diodes and capacitors to superimpose the capacitor discharge voltage and the power supply voltage, thereby increasing the output voltage.

[0003] In related technologies, such as Figure 1 As shown, the bootstrap circuit is generally used in a half-bridge circuit. The upper bridge arm transistor Q1 is connected to the positive terminal of the high-voltage bus (BUS+), and the lower bridge arm transistor Q2 is connected to the negative terminal of the high-voltage bus (BUS-). Furthermore, the drivers of the upper and lower bridge arm transistors Q1 and Q2 typically use a half-bridge driver chip. The upper half-bridge power supply terminal VDDB of the half-bridge driver chip usually draws power from the power supply VDD using a bootstrap method. The bootstrap circuit may include: a bootstrap capacitor C1, a bootstrap diode D1, and a current-limiting resistor R5. Moreover, Zener diodes DZ1 and C3 provide a negative voltage circuit for driving the upper bridge arm transistor Q1, and Zener diodes DZ2 and C4 provide a negative voltage circuit for driving the lower bridge arm transistor Q2.

[0004] However, the voltage of capacitors C3 and C4 can only be established when the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2 are turned on. In the initial stage of the circuit, there is no voltage on capacitors C3 and C4. When the turn-on threshold VGSth of the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2 is small, the direct current stress of the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2 will damage them. Utility Model Content

[0005] This application provides a bootstrap drive circuit and a half-bridge circuit, which solves the problem in the prior art that when the turn-on threshold VGSth of the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2 is small, the direct current stress of the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2 will damage the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] In a first aspect, embodiments of this application provide a bootstrap driving circuit, the bootstrap driving circuit comprising: an independent power supply, an upper bridge arm transistor, a lower bridge arm transistor, an upper bridge arm bootstrap module, a lower bridge arm bootstrap module, an upper bridge arm negative voltage module, and a lower bridge arm negative voltage module.

[0008] The first end of the upper arm boot module is connected to the positive terminal of the independent power supply, and the second end of the upper arm boot module is connected to the second end of the upper arm negative voltage module through a charging diode.

[0009] The first end of the upper arm negative pressure module is connected to the second end of the upper arm boot module through an anti-reverse diode. The second end of the upper arm negative pressure module is connected to the second end of the upper arm tube. The first end of the upper arm tube is connected to the positive terminal of the high voltage bus.

[0010] The first end of the lower arm boot module is connected to the positive terminal of the independent power supply. The second end of the lower arm boot module is connected to the negative terminal of the independent power supply and the first end of the lower arm negative pressure module. The second end of the lower arm negative pressure module is connected to the second end of the lower arm tube. The first end of the lower arm tube is connected to the second end of the upper arm tube. The second end of the lower arm tube is connected to the negative terminal of the high-voltage bus.

[0011] Optionally, the upper bridge arm bootstrap module includes: a first bootstrap diode and a first bootstrap capacitor;

[0012] The first end of the first bootstrap diode is connected to the positive terminal of the independent power supply, the second end of the first bootstrap diode is connected to the first end of the first bootstrap capacitor, and the second end of the first bootstrap capacitor is connected to the second end of the upper bridge arm negative voltage module through the charging diode.

[0013] Optionally, the second terminal of the first bootstrap capacitor is connected to the first terminal of the upper bridge arm negative voltage module through the anti-reverse diode.

[0014] Optionally, the bootstrap driving circuit further includes: a first current-limiting resistor and a second current-limiting resistor;

[0015] The first end of the first current-limiting resistor is connected between the first bootstrap diode and the first bootstrap capacitor, and the second end of the first current-limiting resistor is connected to the second end of the upper bridge arm negative voltage module.

[0016] The first end of the second current-limiting resistor is connected to the positive terminal of the independent power supply, and the second end of the second current-limiting resistor is connected to the second end of the lower bridge arm negative voltage module.

[0017] Optionally, the bootstrap driving circuit further includes: a third current-limiting resistor;

[0018] The third current-limiting resistor is connected in series between the upper bridge arm bootstrap module and the independent power supply.

[0019] Optionally, the bootstrap driving circuit further includes: a first driving resistor and a second driving resistor;

[0020] The first driving resistor is connected to the control terminal of the upper bridge arm transistor;

[0021] The second driving resistor is connected to the control terminal of the lower bridge arm transistor.

[0022] Optionally, the bootstrap driving circuit further includes: a first gate resistor and a second gate resistor;

[0023] The first gate resistor is connected between the control terminal and the second terminal of the upper bridge arm transistor;

[0024] The second gate resistor is connected between the control terminal and the second terminal of the lower bridge arm transistor.

[0025] Optionally, the upper bridge arm negative pressure module includes: a first negative pressure capacitor and a first Zener diode;

[0026] The positive terminal of the first Zener diode is connected to the first terminal of the first negative voltage capacitor, and the negative terminal of the first Zener diode is connected to the second terminal of the first negative voltage capacitor.

[0027] The first end of the first negative voltage capacitor is connected to the second end of the upper bridge arm bootstrap module, and the second end of the first negative voltage capacitor is connected to the second end of the upper bridge arm tube.

[0028] The lower bridge arm negative pressure module includes: a second negative pressure capacitor and a second Zener diode;

[0029] The positive terminal of the second Zener diode is connected to the first terminal of the second negative voltage capacitor, and the negative terminal of the second Zener diode is connected to the second terminal of the second negative voltage capacitor.

[0030] The first end of the second negative voltage capacitor is connected to the second end of the lower bridge arm boot module, and the second end of the second negative voltage capacitor is connected to the second end of the lower bridge arm tube.

[0031] Optionally, the bootstrap driving circuit further includes: a third Zener diode;

[0032] The lower arm boot module is connected to the independent power supply through the third Zener diode. The positive terminal of the third Zener diode is connected to the first end of the lower arm boot module, and the negative terminal of the third Zener diode is connected to the positive terminal of the independent power supply.

[0033] Secondly, embodiments of this application provide a half-bridge circuit, the half-bridge circuit comprising: a driver chip and a bootstrap driver circuit as described in any of the first aspects;

[0034] The first positive pressure terminal of the driving chip is connected to the first terminal of the lower bridge arm bootstrap module, the second terminal of the lower bridge arm negative pressure module, and the control terminal of the lower bridge arm tube, respectively.

[0035] The first negative voltage terminal of the driver chip is connected to the negative terminal of the independent power supply, the first terminal of the lower bridge arm bootstrap module, and the second terminal of the lower bridge arm negative voltage module, respectively.

[0036] The first output terminal of the driver chip is connected to the control terminal of the lower bridge arm transistor.

[0037] The second positive voltage terminal of the driver chip is connected between the first bootstrap diode and the first bootstrap capacitor of the upper bridge arm bootstrap module, and the second positive voltage terminal of the driver chip is also connected to the second terminal of the upper bridge arm negative voltage module.

[0038] The second negative pressure terminal of the driver chip is connected to the first terminal of the upper bridge arm negative pressure module and the second terminal of the upper bridge arm bootstrap module, respectively.

[0039] The second output terminal of the driver chip is connected to the control terminal of the upper bridge arm transistor.

[0040] This application provides a bootstrap driving circuit in which, before the lower bridge arm transistor is turned on, the lower bridge arm negative voltage module is charged and establishes voltage through an independent power supply and the circuit formed by the lower bridge arm negative voltage module. When the lower bridge arm transistor is turned on, the upper bridge arm bootstrap module, through an independent power supply, charges the capacitor and establishes voltage through the circuit formed by the upper bridge arm bootstrap module, the anti-reverse diode, the lower bridge arm transistor, and the lower bridge arm negative voltage module. Simultaneously, the upper bridge arm bootstrap module charges and establishes voltage through the circuit formed by the upper bridge arm bootstrap module, the upper bridge arm negative voltage module, and the anti-reverse diode, thereby providing a stable negative voltage for both the upper and lower bridge arm transistors. This ensures the stable turn-off of both transistors and improves the reliability and stability of the bootstrap driving circuit. Attached Figure Description

[0041] Figure 1 This is a circuit diagram of a half-bridge circuit proposed in the prior art;

[0042] Figure 2 This is a circuit diagram of a half-bridge circuit involved in a bootstrap driving circuit proposed in an embodiment of this application.

[0043] Figure 3 This is a circuit diagram of a bootstrap driving circuit proposed in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the driving waveform of a bootstrap driving circuit proposed in an embodiment of this application at the initial moment. Detailed Implementation

[0045] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known circuit principles have been omitted so as not to obscure the description of this application with unnecessary detail.

[0046] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “the,” “the,” and “the” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise.

[0047] A bootstrap circuit, also known as a boost circuit, uses electronic components such as diodes and capacitors to superimpose the capacitor discharge voltage and the power supply voltage, thereby increasing the output voltage.

[0048] like Figure 1 As shown, the bootstrap circuit is generally used in a half-bridge circuit. The upper bridge arm transistor Q1 is connected to the positive terminal of the high-voltage bus (BUS+), and the lower bridge arm transistor Q2 is connected to the negative terminal of the high-voltage bus (BUS-). The upper bridge arm transistors Q1 and Q2 are generally driven by a Half-Bridge Driver chip. The upper half-bridge power supply VDDB of the chip usually draws power from the power supply VDD in a bootstrap manner. The bootstrap circuit includes a bootstrap capacitor C1, a bootstrap diode D1, and a current-limiting resistor R5. Zener diode DZ1 and capacitor C3 provide a negative voltage circuit for driving Q1, and Zener diode DZ2 and capacitor C4 provide a negative voltage circuit for driving Q2.

[0049] The voltage across capacitors C3 and C4 can only be established when the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2 are turned on. Only after the voltage is established can a negative voltage be provided to turn off the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2, ensuring that the upper bridge arm transistor Q1 and the lower bridge arm transistor Q2 are reliably turned off.

[0050] However, initially, capacitors C3 and C4 have no voltage, meaning that upper arm transistor Q1 and lower arm transistor Q2 have no negative voltage when turned off. Due to the influence of parasitic parameters, when lower arm transistor Q2 is turned on, it will drive up the gate-source voltage VGS1 of upper arm transistor Q1, and when upper arm transistor Q1 is turned on, it will drive up the gate-source voltage VGS2 of lower arm transistor Q2. When the turn-on threshold VGSth of upper arm transistor Q1 and lower arm transistor Q2 is small, it will cause the DC current stress of upper arm transistor Q1 and lower arm transistor Q2 to damage them, resulting in unreliable equipment.

[0051] Therefore, this application embodiment proposes a bootstrap driving circuit. During the operation of the bootstrap driving circuit, before the lower bridge arm transistor is turned on, the second negative voltage capacitor has been charged through the independent power supply, the second Zener diode, the second current limiting resistor, the second negative voltage capacitor and the second Zener diode circuit to establish a voltage. The voltage magnitude is determined by the second Zener diode, and the lower bridge arm transistor will reliably turn on and off.

[0052] Furthermore, when the lower arm transistor is turned on, the first bootstrap capacitor is charged to establish voltage through the upper arm bootstrap module, independent power supply, third current limiting resistor, first bootstrap diode, first bootstrap capacitor, charging diode, anti-reverse diode, lower arm transistor, second negative voltage capacitor and second Zener diode circuit.

[0053] At the same time, the first bootstrap capacitor will charge the first negative voltage capacitor to establish voltage through the upper bridge arm negative voltage module, the first bootstrap capacitor, the first current limiting resistor, the first negative voltage capacitor, the first Zener diode and the anti-reverse diode circuit.

[0054] See Figure 2 , Figure 2 This is a circuit diagram of a half-bridge circuit involved in a bootstrap driving circuit proposed in an embodiment of this application. The half-bridge circuit may include a driver chip 210 and a bootstrap driving circuit 220.

[0055] Specifically, the first positive voltage terminal VDDA of the driver chip 210 is connected to the first terminal of the lower bridge arm bootstrap module, the second terminal of the lower bridge arm negative voltage module, and the control terminal of the lower bridge arm transistor Q2, respectively; the first negative voltage terminal VEEA of the driver chip 210 is connected to the negative terminal of the independent power supply VDD, the first terminal of the lower bridge arm bootstrap module, and the second terminal of the lower bridge arm negative voltage module, respectively; and the first output terminal OUTA of the driver chip 210 is connected to the control terminal of the lower bridge arm transistor Q2.

[0056] Similarly, the second positive voltage terminal VDDB of the driver chip 210 is connected between the first bootstrap diode D1 and the first bootstrap capacitor C1 of the upper arm bootstrap module, and the second positive voltage terminal VDDB of the driver chip 210 is also connected to the second terminal of the upper arm negative voltage module; the second negative voltage terminal VEEB of the driver chip 210 is connected to the first terminal of the upper arm negative voltage module and the second terminal of the upper arm bootstrap module respectively; the second output terminal OUTB of the driver chip 210 is connected to the control terminal of the upper arm transistor Q1.

[0057] The upper arm self-lifting module, upper arm negative pressure module, lower arm self-lifting module, and lower arm negative pressure module are detailed below.

[0058] It should be noted that the driver chip 210 can be a Half-Bridge Driver dual-channel driver chip, an optocoupler, or a single-channel driver chip. This application embodiment does not specifically limit the driver chip 210.

[0059] The bootstrap drive circuit in the half-bridge circuit will be described in detail below.

[0060] See Figure 3 , Figure 3This is a circuit diagram of a bootstrap driving circuit proposed in an embodiment of this application. The bootstrap driving circuit may include: an independent power supply VDD310, an upper bridge arm transistor Q1 320, a lower bridge arm transistor Q2 330, an upper bridge arm bootstrap module 340, a lower bridge arm bootstrap module 350, an upper bridge arm negative voltage module 360, and a lower bridge arm negative voltage module 370.

[0061] The first end of the upper arm bootstrap module 340 is connected to the positive terminal of the independent power supply VDD310, and the second end of the upper arm bootstrap module 340 is connected to the second end of the upper arm transistor Q1 320 through the charging diode D3.

[0062] Furthermore, the first end of the upper arm negative pressure module 360 ​​is connected to the second end of the upper arm bootstrap module 340 through the anti-reverse diode D2, the second end of the upper arm negative pressure module 360 ​​is connected to the second end of the upper arm tube Q1 320, and the first end of the upper arm tube Q1 320 is connected to the positive terminal BUS+ of the high voltage bus.

[0063] In addition, the first end of the lower arm boot module 350 is connected to the positive terminal of the independent power supply VDD310, the second end of the lower arm boot module 350 is connected to the negative terminal of the independent power supply VDD310 and the first end of the lower arm negative voltage module 370, the second end of the lower arm negative voltage module 370 is connected to the second end of the lower arm tube Q2 330, the first end of the lower arm tube Q2 330 is connected to the second end of the upper arm tube Q1 320, and the second end of the lower arm tube Q2 330 is connected to the negative terminal BUS- of the high voltage bus.

[0064] For example, the lower arm bootstrap module 350 may include a bootstrap capacitor C2. This application embodiment does not specifically limit the devices included in the lower arm bootstrap module 350.

[0065] It should be noted that, in practical applications, both the upper bridge arm transistor Q1 320 and the lower bridge arm transistor Q2 330 can be silicon carbide (SiC) devices, insulated gate bipolar transistors (IGBTs), or metal-oxide-semiconductor field-effect transistors (MOSFETs). This application does not specifically limit the upper bridge arm transistor Q1 320 and the lower bridge arm transistor Q2 330.

[0066] In summary, before the lower bridge arm transistor is turned on, the lower bridge arm negative voltage module has already been charged and established through a circuit formed by its independent power supply. When the lower bridge arm transistor is turned on, the upper bridge arm bootstrap module, through its independent power supply, charges the capacitor and establishes voltage through a circuit formed by the upper bridge arm bootstrap module, the reverse protection diode, the lower bridge arm transistor, and the lower bridge arm negative voltage module. Simultaneously, the upper bridge arm bootstrap module charges and establishes voltage through a circuit formed by its own components, the upper bridge arm negative voltage module, and the reverse protection diode, thus providing a stable negative voltage for both the upper and lower bridge arm transistors. This ensures stable turn-off of both transistors and improves the reliability and stability of the bootstrap drive circuit.

[0067] In one alternative embodiment, the upper arm bootstrap module 340 may include a first bootstrap diode D1 and a first bootstrap capacitor C1.

[0068] The first end of the first bootstrap diode D1 is connected to the positive terminal of the independent power supply VDD310, the second end of the first bootstrap diode D1 is connected to the first end of the first bootstrap capacitor C1, and the second end of the first bootstrap capacitor C1 is connected to the second end of the upper bridge arm negative voltage module 360 ​​through the charging diode D3.

[0069] Furthermore, the second terminal of the first bootstrap capacitor C1 is connected to the first terminal of the upper bridge arm negative voltage module 360 ​​through the anti-reverse diode D2.

[0070] Furthermore, the bootstrap driving circuit may also include: a first current-limiting resistor R7 and a second current-limiting resistor R6.

[0071] The first end of the first current-limiting resistor R7 is connected between the first bootstrap diode D1 and the first bootstrap capacitor C1, and the second end of the first current-limiting resistor R7 is connected to the first end of the upper bridge arm negative voltage module 360.

[0072] Furthermore, the first end of the second current-limiting resistor R6 is connected to the positive terminal of the independent power supply VDD310, and the second end of the second current-limiting resistor R6 is connected to the second end of the lower bridge arm negative pressure module 370.

[0073] It should be noted that the bootstrap drive circuit may also include a third current-limiting resistor R5.

[0074] The third current-limiting resistor R5 is connected in series between the upper bridge arm bootstrap module 340 and the independent power supply VDD310.

[0075] In another alternative embodiment, the upper bridge arm negative pressure module 360 ​​may include: a first negative pressure capacitor C3 and a first Zener diode DZ1.

[0076] The positive terminal of the first Zener diode DZ1 is connected to the first terminal of the first negative capacitor C3, and the negative terminal of the first Zener diode DZ1 is connected to the second terminal of the first negative capacitor C3; the first terminal of the first negative capacitor C3 is connected to the second terminal of the upper bridge arm bootstrap module 340, and the second terminal of the first negative capacitor C3 is connected to the second terminal of the upper bridge arm transistor Q1 320.

[0077] Similarly, the lower bridge arm negative pressure module 370 may include: a second negative pressure capacitor C4 and a second Zener diode DZ2.

[0078] Specifically, the positive terminal of the second Zener diode DZ2 is connected to the first terminal of the second negative capacitor C4, and the negative terminal of the second Zener diode DZ2 is connected to the second terminal of the second negative capacitor C4. Furthermore, the first terminal of the second negative capacitor C4 is connected to the second terminal of the lower bridge arm bootstrap module 350, and the second terminal of the second negative capacitor C4 is connected to the control terminal and the second terminal of the lower bridge arm transistor Q2 330.

[0079] Optionally, the bootstrap drive circuit may also include a third Zener diode, DZ3.

[0080] The lower arm boot module 350 is connected to the independent power supply VDD310 through the third Zener diode DZ3. The positive terminal of the third Zener diode DZ3 is connected to the first end of the lower arm boot module 350, and the negative terminal of the third Zener diode DZ3 is connected to the positive terminal of the independent power supply VDD310.

[0081] Furthermore, the Zener diodes DZ1, DZ2, and DZ3 can regulate voltages between 0 and 20 volts, matching the gate-source voltage range of the upper arm transistor Q1 320 and the lower arm transistor Q2 330.

[0082] It should be noted that the voltage regulation values ​​of the first Zener diode DZ1, the second Zener diode DZ2, and the third Zener diode DZ3 can be determined based on the gate-source voltage of the upper bridge arm transistor Q1 320 and / or the lower bridge arm transistor Q2 330. For example, the voltage regulation value range of any one of the first Zener diode DZ1, the second Zener diode DZ2, and the third Zener diode DZ3 can be between 0 volts (V) and 20V. In this embodiment of the application, no specific limitation is made on the voltage regulation value range of the first Zener diode DZ1, the second Zener diode DZ2, and the third Zener diode DZ3.

[0083] In another alternative embodiment, the bootstrap driving circuit may further include: a first driving resistor R1 and a second driving resistor R2.

[0084] The first driving resistor R1 is connected to the control terminal of the upper bridge arm transistor Q1 320, and the second driving resistor R2 is connected to the control terminal of the lower bridge arm transistor Q2 330.

[0085] In addition, the bootstrap drive circuit may also include: a first gate resistor R3 and a second gate resistor R4.

[0086] The first gate resistor R3 is connected between the control terminal and the second terminal of the upper bridge arm transistor Q1 320, and the second gate resistor R4 is connected between the control terminal and the second terminal of the lower bridge arm transistor Q2 330.

[0087] See Figure 4 , Figure 4 This is a schematic diagram of the driving waveform of a bootstrap driving circuit proposed in an embodiment of this application at the initial moment. Figure 4 The graph at the top shows the voltage waveforms corresponding to the first bootstrap capacitor C1 and the first negative voltage capacitor C3, respectively. It can be seen that the voltage of the first bootstrap capacitor C1 and the voltage of the first negative voltage capacitor C3 are initially the same. After a period of time, the voltage of the first bootstrap capacitor C1 increases significantly, while the voltage of the first negative voltage capacitor C3 shows a smaller increase.

[0088] and, Figure 4 The graph at the bottom shows the gate-source voltage waveforms of the upper bridge arm transistor Q1 320 and the lower bridge arm transistor Q2 330, respectively. It can be seen that the gate-source voltage of the upper bridge arm transistor Q1 320 is 0 potential, and the gate-source voltage of the lower bridge arm transistor Q2 330 is negative potential. After a period of time, the upper bridge arm transistor Q1 320 and the lower bridge arm transistor Q2 are turned on alternately.

[0089] Accordingly, based on the above bootstrap drive circuit, during operation, a negative voltage can be established first for the first negative voltage capacitor C3 and the second negative voltage capacitor C4 before the upper bridge arm transistor Q1 320 and the lower bridge arm transistor Q2 330 start working, so as to ensure that the upper bridge arm transistor Q1 320 and the lower bridge arm transistor Q2 330 are safe and reliable when switching.

[0090] Specifically, the current flows from the independent power supply VDD310 through the third Zener diode DZ3 to the second current-limiting resistor R6, and then returns to the independent power supply VDD310 through the second negative voltage capacitor C4 to charge the second negative voltage capacitor C4 and establish voltage.

[0091] Moreover, the current can flow from the independent power supply VDD310 through the third current-limiting resistor R5, the bootstrap diode D1 to the first bootstrap capacitor C1, then through the charging diode D3 to the lower bridge arm transistor Q2 330, and then through the second negative voltage capacitor C4 back to the independent power supply VDD310. At this time, the lower bridge arm transistor Q2 330 is in the conducting state, charging the first bootstrap capacitor C1 to establish voltage.

[0092] In addition, current can flow from the first bootstrap capacitor C1 through the first current-limiting resistor R7 to the first negative voltage capacitor C3, and then return to the first bootstrap capacitor C1 through the anti-reverse diode D2 to charge the first negative voltage capacitor C3 and establish voltage.

[0093] Correspondingly, when the first output terminal OUTA is low, the current can flow from the second negative voltage capacitor C4 through the lower bridge arm transistor Q2 330 to the second drive resistor R2, and then return to the second negative voltage capacitor C4 through the first output terminal OUTA and the first negative voltage terminal VEEA. The second negative voltage capacitor C4 provides a negative voltage shutdown power supply to the lower bridge arm transistor Q2 330.

[0094] Furthermore, when the second output terminal OUTB is high, current flows from the second positive voltage terminal VDDB through the first drive resistor R1 to the upper bridge arm transistor Q1 320, and then returns to the second negative voltage terminal VEEB through the first negative voltage capacitor C3, turning on the upper bridge arm transistor Q1 320. At this time, the first output terminal OUTA is low, and the lower bridge arm transistor Q2 330 is turned off.

[0095] Similarly, when the second output terminal OUTB is low, the current flows from the first negative voltage capacitor C3 through the upper bridge arm transistor Q1320 to the first drive resistor R1, and then returns to the first negative voltage capacitor C3 through the second output terminal OUTB and the second negative voltage terminal VEEB. The upper bridge arm transistor Q1320 is turned off, and the first negative voltage capacitor C3 provides a negative voltage shutdown power supply to the upper bridge arm transistor Q1320.

[0096] Furthermore, when the first output terminal OUTA is high, current flows from the first positive voltage terminal VDDA through the second drive resistor R2 to the lower bridge arm transistor Q2 330, and then returns to the first negative voltage terminal VEEA through the second negative voltage capacitor C4, turning on the lower bridge arm transistor Q2 330. At this time, the second output terminal OUTB is low, and the upper bridge arm transistor Q1 320 is turned off.

[0097] It should be noted that in practical applications, in order to avoid a short circuit caused by the simultaneous conduction of the upper bridge arm transistor Q1 320 and the lower bridge arm transistor Q2 330, a dead time is usually set between the first output terminal OUTA and the second output terminal OUTB. That is, after one signal is turned off, a certain period of time is required before the other signal is turned on.

[0098] In summary, during the operation of the bootstrap drive circuit, before the lower bridge arm transistor Q2 330 is turned on, the second negative voltage capacitor C4 has been charged and established through the independent power supply VDD, the second Zener diode DZ2, the second current limiting resistor R6, the second negative voltage capacitor C4, and the second Zener diode DZ2. The voltage magnitude is determined by the second Zener diode DZ2, and the lower bridge arm transistor Q2 330 will reliably turn on and off.

[0099] Furthermore, when the lower arm transistor Q2 330 is turned on, the first bootstrap capacitor C1 is charged to establish voltage through the upper arm bootstrap module 340, independent power supply VDD, third current limiting resistor R5, first bootstrap diode D1, first bootstrap capacitor C1, charging diode D3, anti-reverse diode D2, lower arm transistor Q2 330, second negative voltage capacitor C4, and second Zener diode DZ2 circuit.

[0100] At the same time, the first bootstrap capacitor C1 will charge the first negative voltage capacitor C3 to establish voltage through the circuit of the upper bridge arm negative voltage module 360, the first bootstrap capacitor C1, the first current limiting resistor R7, the first negative voltage capacitor C3, the first Zener diode DZ1 and the anti-reverse diode D2.

[0101] It should be noted that in practical applications, half-bridge driver chips are usually equipped with undervoltage protection. When the upper arm of the half-bridge driver chip is generating a waveform normally, the voltage on the first bootstrap capacitor C1 has exceeded the undervoltage threshold. At this time, the voltage of the first negative voltage capacitor C3 has been established, thus achieving the reliable conditions for the upper arm transistor Q1 320 to be turned on and off.

[0102] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0103] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0104] In the embodiments provided in this application, it should be understood that the disclosed apparatus / devices and methods can be implemented in other ways. For example, the apparatus / device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0105] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0106] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0107] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0108] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0109] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A bootstrap driving circuit, characterized in that, The bootstrap drive circuit includes: an independent power supply, an upper arm transistor, a lower arm transistor, an upper arm bootstrap module, a lower arm bootstrap module, an upper arm negative pressure module, and a lower arm negative pressure module. The first end of the upper arm boot module is connected to the positive terminal of the independent power supply, and the second end of the upper arm boot module is connected to the second end of the upper arm negative voltage module through a charging diode. The first end of the upper arm negative pressure module is connected to the second end of the upper arm boot module through an anti-reverse diode. The second end of the upper arm negative pressure module is connected to the second end of the upper arm tube. The first end of the upper arm tube is connected to the positive terminal of the high voltage bus. The first end of the lower arm boot module is connected to the positive terminal of the independent power supply. The second end of the lower arm boot module is connected to the negative terminal of the independent power supply and the first end of the lower arm negative pressure module. The second end of the lower arm negative pressure module is connected to the second end of the lower arm tube. The first end of the lower arm tube is connected to the second end of the upper arm tube. The second end of the lower arm tube is connected to the negative terminal of the high-voltage bus.

2. The bootstrap driving circuit according to claim 1, characterized in that, The upper bridge arm bootstrap module includes: a first bootstrap diode and a first bootstrap capacitor; The first end of the first bootstrap diode is connected to the positive terminal of the independent power supply, the second end of the first bootstrap diode is connected to the first end of the first bootstrap capacitor, and the second end of the first bootstrap capacitor is connected to the second end of the upper bridge arm negative voltage module through the charging diode.

3. The bootstrap driving circuit according to claim 2, characterized in that, The second terminal of the first bootstrap capacitor is connected to the first terminal of the upper bridge arm negative voltage module through the anti-reverse diode.

4. The bootstrap driving circuit according to claim 2, characterized in that, The bootstrap driving circuit further includes: a first current-limiting resistor and a second current-limiting resistor; The first end of the first current-limiting resistor is connected between the first bootstrap diode and the first bootstrap capacitor, and the second end of the first current-limiting resistor is connected to the second end of the upper bridge arm negative voltage module. The first end of the second current-limiting resistor is connected to the positive terminal of the independent power supply, and the second end of the second current-limiting resistor is connected to the second end of the lower bridge arm negative voltage module.

5. The bootstrap driving circuit according to claim 4, characterized in that, The bootstrap driving circuit further includes: a third current-limiting resistor; The third current-limiting resistor is connected in series between the upper bridge arm bootstrap module and the independent power supply.

6. The bootstrap driving circuit according to any one of claims 1 to 5, characterized in that, The bootstrap driving circuit further includes: a first driving resistor and a second driving resistor; The first driving resistor is connected to the control terminal of the upper bridge arm transistor; The second driving resistor is connected to the control terminal of the lower bridge arm transistor.

7. The bootstrap driving circuit according to any one of claims 1 to 5, characterized in that, The bootstrap driving circuit further includes: a first gate resistor and a second gate resistor; The first gate resistor is connected between the control terminal and the second terminal of the upper bridge arm transistor; The second gate resistor is connected between the control terminal and the second terminal of the lower bridge arm transistor.

8. The bootstrap driving circuit according to any one of claims 1 to 5, characterized in that, The upper bridge arm negative pressure module includes: a first negative pressure capacitor and a first voltage regulator; The positive terminal of the first Zener diode is connected to the first terminal of the first negative voltage capacitor, and the negative terminal of the first Zener diode is connected to the second terminal of the first negative voltage capacitor. The first end of the first negative voltage capacitor is connected to the second end of the upper bridge arm bootstrap module, and the second end of the first negative voltage capacitor is connected to the second end of the upper bridge arm tube. The lower bridge arm negative pressure module includes: a second negative pressure capacitor and a second Zener diode; The positive terminal of the second Zener diode is connected to the first terminal of the second negative voltage capacitor, and the negative terminal of the second Zener diode is connected to the second terminal of the second negative voltage capacitor. The first end of the second negative voltage capacitor is connected to the second end of the lower bridge arm boot module, and the second end of the second negative voltage capacitor is connected to the second end of the lower bridge arm tube.

9. The bootstrap driving circuit according to claim 8, characterized in that, The bootstrap driving circuit also includes: a third Zener diode; The lower arm boot module is connected to the independent power supply through the third Zener diode. The positive terminal of the third Zener diode is connected to the first end of the lower arm boot module, and the negative terminal of the third Zener diode is connected to the positive terminal of the independent power supply.

10. A half-bridge circuit, characterized in that, The half-bridge circuit includes: a driver chip and a bootstrap driver circuit as described in any one of claims 1 to 9; The first positive pressure terminal of the driving chip is connected to the first terminal of the lower bridge arm bootstrap module, the second terminal of the lower bridge arm negative pressure module, and the control terminal of the lower bridge arm tube, respectively. The first negative voltage terminal of the driver chip is connected to the negative terminal of the independent power supply, the first terminal of the lower bridge arm bootstrap module, and the second terminal of the lower bridge arm negative voltage module, respectively. The first output terminal of the driver chip is connected to the control terminal of the lower bridge arm transistor. The second positive voltage terminal of the driver chip is connected between the first bootstrap diode and the first bootstrap capacitor of the upper bridge arm bootstrap module, and the second positive voltage terminal of the driver chip is also connected to the second terminal of the upper bridge arm negative voltage module. The second negative pressure terminal of the driver chip is connected to the first terminal of the upper bridge arm negative pressure module and the second terminal of the upper bridge arm bootstrap module, respectively. The second output terminal of the driver chip is connected to the control terminal of the upper bridge arm transistor.

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