Bootstrap driving circuit and switching power supply

Abstract

The utility model relates to a bootstrap driving circuit and a switching power supply, the bootstrap driving circuit comprises a first isolation circuit, a bootstrap circuit, a first driving circuit and a first switching device, the first isolation circuit is configured to transmit a first control signal to the first driving circuit in an isolated manner, and the bootstrap circuit is configured to drive the first driving circuit to work; when the first driving circuit is configured to work, the first switching device is controlled to be switched on and switched off periodically according to the first control signal, so that the isolation of the power device and the control device can be realized by using the high-voltage-resistant isolation circuit, and the influence of the high voltage of the power device side on the control device which is not resistant to the high voltage is reduced; therefore, the bootstrap drive circuit can resist high voltage to meet the requirements of high-voltage application scenarios, and the application range is expanded.

Description

Technical Field

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

[0002] With the development and rise of the new energy industry and the energy storage industry, high-power switching power supplies have developed rapidly due to their advantages of high efficiency, energy saving, compact size, stability and reliability.

[0003] However, the bootstrap drive circuit of the switching power supply in the related art has the problem of being unable to meet the needs of high-voltage application scenarios. Utility Model Content

[0004] The embodiments of the present application provide a bootstrap drive circuit and a switching power supply to solve the problem in the related art that the bootstrap drive circuit of the switching power supply cannot meet the needs of high-voltage application scenarios.

[0005] An embodiment of the present application provides a bootstrap drive circuit, which includes: a first isolation circuit, a bootstrap circuit, a first drive circuit and a first switching device, wherein the first isolation circuit is configured to isolate and transmit a first control signal to the first drive circuit; the bootstrap circuit is configured to drive the first drive circuit to operate; and the first drive circuit is configured to control the first switch device to periodically open and close according to the first control signal when operating.

[0006] The first end of the first switch device is configured to be connected to an external power source, the voltage of the second end of the first switch device is a floating voltage, and the first switch device is configured to drive an external load.

[0007] Among them, the bootstrap circuit includes a bootstrap diode and a bootstrap capacitor, the positive electrode of the bootstrap diode is connected to the first power supply voltage, the negative electrode of the bootstrap diode is connected to the first end of the bootstrap capacitor, the second end of the bootstrap capacitor is connected to the floating ground, and the voltage at the first end of the bootstrap capacitor is configured to drive the first drive circuit to work.

[0008] The bootstrap drive circuit further includes: a second drive circuit and a second switching device, wherein the second drive circuit is configured to control the second switching device to periodically turn on and off, and the second switching device is configured to pull down the voltage of the second end of the first switching device to the first voltage when turned on.

[0009] The first end of the second switch device is connected to the second end of the first switch device, and the second end of the second switch device is grounded.

[0010] The bootstrap drive circuit further includes: a second isolation circuit, the second isolation circuit is configured to isolate and transmit the second control signal to the second drive circuit, and the second drive circuit is specifically configured to control the second switch device to periodically turn on and off according to the second control signal.

[0011] The first control signal and the second control signal are pulse width modulation signals, and a phase difference between the first control signal and the second control signal is 180 degrees.

[0012] Wherein, the first isolation circuit and the second isolation circuit include digital isolators.

[0013] The bootstrap driving circuit further includes a digital controller, which is configured to send a first control signal and a second control signal to the first isolation circuit and the second isolation circuit respectively.

[0014] An embodiment of the present application further provides a switching power supply, which includes any one of the above-mentioned bootstrap drive circuits.

[0015] The bootstrap drive circuit and switching power supply provided in the present application utilize a first isolation circuit to isolate and transmit a first control signal to the first drive circuit, and utilize the bootstrap circuit to drive the first drive circuit to work. When the first drive circuit is working, it can control the first switching device to periodically open and close according to the first control signal, so that the power device and the control device can be isolated by utilizing a high-voltage resistant isolation circuit to reduce the influence of the high voltage on the power device side on the control device that is not resistant to high voltage, thereby achieving the high-voltage resistance performance of the bootstrap drive circuit to meet the needs of high-voltage application scenarios and expand the scope of application. In addition, this is also conducive to the flexible layout of the power part circuit and the drive part circuit in the bootstrap drive circuit to improve the practicality of the switching power supply drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0017] Figure 1 A schematic diagram of the structure of a bootstrap drive circuit provided in an embodiment of the present application;

[0018] Figure 2 Another structural schematic diagram of the bootstrap driving circuit provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of waveforms of a first control signal and a second control signal provided in an embodiment of the present application;

[0020] Figure 4 Another structural schematic diagram of the bootstrap driving circuit provided in an embodiment of the present application;

[0021] Figure 5 A schematic diagram of the structure of a switching power supply provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0024] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0026] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0027] With the development and rise of the new energy industry and the energy storage industry, high-power switching power supplies have developed rapidly due to their advantages of high efficiency, energy saving, compact size, and stability and reliability.

[0028] The driving circuit in the switching power supply is located between the main power circuit of the power supply and the digital control chip. Its essence is to amplify the PWM (Pulse Width Modulation) signal generated by the digital control chip to drive the opening and closing of power switching devices with different withstand voltage levels.

[0029] In the related art, there are many types of drive circuits, for example, a drive circuit using a photocoupler isolation circuit, a drive circuit using a transformer isolation circuit, and a bootstrap drive circuit.

[0030] Among them, the technical solution of using optocoupler isolation drive circuit is to use optocoupler to convert the electrical signal emitted by the digital control chip into an optical signal, and then convert the optical signal into an electrical signal to realize signal transmission and isolation, and transmit the signal to the driver chip to drive the next stage.

[0031] The technical solution of using transformer isolation drive circuit is to convert the electrical signal sent by the digital control chip into magnetism, and then convert it from magnetism to electrical signal, so as to realize signal transmission and isolation, and realize voltage conversion.

[0032] The bootstrap driving circuit can realize bootstrap and driving in one chip.

[0033] However, the technical solution of using a photoelectric coupler to isolate the drive circuit has the following disadvantages:

[0034] The optocoupler needs an independent power supply, which increases the complexity of the circuit and the cost;

[0035] The transmission delay of the optocoupler is relatively large. To ensure the accuracy of the switch device on and off, the structural parameters of each path must be consistent, so that the delay of each path is consistent, which increases the difficulty of design and reduces reliability.

[0036] The switching speed of the optocoupler is slow, which causes a large delay on the leading and trailing edges of the driving pulse, making it difficult to apply it at high frequencies.

[0037] The technical solution of using a transformer to isolate the drive circuit has the following disadvantages:

[0038] Easily affected by parasitic parameters;

[0039] The size of the isolation transformer is relatively large and the layout is not flexible enough;

[0040] High energy consumption and low efficiency;

[0041] The waveform quality is poor.

[0042] The technical solution of the bootstrap drive circuit has the following disadvantages:

[0043] The voltage resistance of the bootstrap drive circuit is not high enough to meet the needs of high-voltage application scenarios;

[0044] The layout of the power circuit and the drive circuit is not flexible enough.

[0045] In view of the above problems, the embodiments of the present application provide a bootstrap drive circuit and a switching power supply to solve the problem that the bootstrap drive circuit of the switching power supply in the related art cannot meet the needs of high-voltage application scenarios due to insufficient withstand voltage.

[0046] The following is a detailed description with reference to specific embodiments. It should be noted that the serial numbers of the following embodiments are not intended to limit the preferred order of the embodiments.

[0047] See also Figure 1 , Figure 1 Schematic diagram of the structure of the bootstrap drive circuit provided in the embodiment of the present application. Figure 1As shown, the bootstrap drive circuit 100 may include a first isolation circuit 101, a bootstrap circuit 102, a first drive circuit 103 and a first switch device Q1, wherein the first isolation circuit 101 is configured to isolate and transmit the first control signal PWM1 to the first drive circuit 103, the bootstrap circuit 102 is configured to drive the first drive circuit 103 to work, and the first drive circuit 103 is configured to control the first switch device Q1 to be periodically turned on and off according to the first control signal PWM1 during operation, thereby realizing the bootstrap drive of the first switch device Q1, and realizing the control of the first switch device Q1 by using the first isolation circuit 101 with high voltage resistance. The power device and the control device are isolated to reduce the impact of the high voltage on the power device side on the control device that is not resistant to high voltage. The first isolation circuit 101 has a high withstand voltage value, so the withstand voltage value of the bootstrap drive circuit 100 can be increased to achieve the high voltage resistance performance of the bootstrap drive circuit 100, and the bootstrap drive of the first switching device Q1 can be achieved in the high voltage application scenario, so that the bootstrap drive circuit 100 can meet the needs of the high voltage application scenario and expand the scope of application. In addition, this is also conducive to the flexible layout of the power part circuit and the drive part circuit in the bootstrap drive circuit 100 to improve the practicality of the switching power supply drive circuit.

[0048] The first isolation circuit 101 may include a digital isolator (e.g., a digital isolation chip), and the digital isolator may receive a first control signal PWM1 sent by the control device, and isolate and transmit the received first control signal PWM1 to the first drive circuit 103. The first control signal PWM1 may be a pulse width modulated signal, and its high level and low level may drive the first switch device Q1 to turn on and off, respectively.

[0049] In some embodiments, the bootstrap circuit 102 may be specifically configured to provide a driving voltage to the first driving circuit 103 to drive the first driving circuit 103 to work. Furthermore, the first driving circuit 103 may be specifically configured to control the first switching device Q1 to be periodically turned on and off according to the received first control signal PWM1 when the driving voltage is greater than or equal to the target voltage, so as to achieve the bootstrap driving of the first switching device Q1. The target voltage may be the operating voltage of the first driving circuit 103, that is, the first driving circuit 103 will work only when the driving voltage is greater than or equal to the target voltage, and will not work when the driving voltage is less than the target voltage.

[0050] In some embodiments, the first end of the first switching device Q1 can be configured to be connected to an external power supply, the voltage at the second end of the first switching device Q1 can be a floating voltage, and can be configured to drive an external load, so that when the bootstrap drive circuit 100 is applied to a switching power supply, it can convert the voltage VIN of the external power input switching power supply into a specified output voltage VOUT to drive the external load to operate.

[0051] Furthermore, it can be understood that in this embodiment, by using the first isolation circuit 101 to isolate and transmit the first control signal PWM1 to the first drive circuit 103, the isolation of the power device and the control device is achieved, which can reduce the influence of the high voltage on the power device side on the control device with poor high voltage resistance performance, and the first isolation circuit 101 can use a high voltage resistant isolation circuit, so the high voltage resistance performance of the bootstrap drive circuit 100 can be achieved, that is, when the voltage VIN of the external power input switching power supply is high voltage (for example, 700V), the bootstrap drive circuit 100 can still drive the external load to work normally. In addition, the scheme also has the characteristics of simple circuit devices, mature and reliable devices, low cost, small size, high reliability, high frequency and flexible layout.

[0052] In some examples, the first switching device Q1 may be a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), and the first end of the first switching device Q1 may be one of the source and the drain of the first switching device Q1, and the second end of the first switching device Q1 may be the other of the source and the drain of the first switching device Q1.

[0053] Furthermore, the first driving circuit 104 can be specifically configured to output the received first control signal PWM1 to the control terminal of the first switching device Q1 when the driving voltage is greater than or equal to the target voltage, so as to control the first switching device Q1 to be periodically turned on and off. The connection point SW can be used as a potential reference point of the floating ground, and the floating ground and the connection point SW can be connected internally through the first switching device Q1.

[0054] In some embodiments, Figure 2 As shown, the bootstrap circuit 102 may include a bootstrap diode D1 and a bootstrap capacitor C62, the positive electrode of the bootstrap diode D1 is connected to the first power supply voltage V1 (for example, 12V), the negative electrode of the bootstrap diode is connected to the first end of the bootstrap capacitor C62, the second end of the bootstrap capacitor C62 is connected to the floating ground GND_S1, and the driving voltage provided by the bootstrap circuit 102 to the first driving circuit 103 can be the voltage of the first end of the bootstrap capacitor C62.

[0055] Specifically, during the off period of the first switch device Q1, the voltage at the second end of the first switch device Q1 (that is, the voltage of the floating ground GND_S1) is pulled down to a first voltage (for example, about 0 V) ​​that is less than the first power supply voltage. During the on period of the first switch device Q1, the voltage at the second end of the first switch device Q1 (that is, the voltage of the floating ground GND_S1) is raised to a second voltage (for example, about 350 V) that is greater than the first power supply voltage.

[0056] Furthermore, when the voltage of the floating ground GND_S1 (i.e., the voltage of the second end of the first switch device Q1) is less than the first power supply voltage V1, the first power supply voltage V1 can charge the bootstrap capacitor C62 through the bootstrap diode D1, so as to raise the voltage of the first end of the bootstrap capacitor C62 to be greater than or equal to the target voltage, thereby driving the first drive circuit 103 to work. When the voltage of the floating ground GND_S1 (i.e., the voltage of the second end of the first switch device Q1) is greater than the first power supply voltage V1, the first power supply voltage V1 no longer charges the bootstrap capacitor C62 through the bootstrap diode D1, and the bootstrap capacitor C62 can supply power to the first drive circuit 103 by discharging, so as to drive the first drive circuit 103 to work. Therefore, the bootstrap circuit 102 can realize stable power supply to the first drive circuit 103.

[0057] In some examples, the bootstrap diode D1 can be a fast recovery diode with sufficient voltage resistance.

[0058] In some embodiments, Figure 2 As shown, the bootstrap driving circuit 100 may further include a second driving circuit 104 and a second switching device Q2, wherein the second driving circuit 104 may be configured to control the second switching device Q2 to be periodically turned on and off, and the second switching device Q2 may be configured to pull down the voltage of the second end of the first switching device Q2 (that is, the voltage of the floating ground GND_S1) to a first voltage (e.g., approximately 0 V) ​​when turned on. Accordingly, the first switching device Q1 may be configured to raise the voltage of the floating ground GND_S1 to a second voltage (e.g., approximately 350 V) when turned on.

[0059] Specifically, a first end of the second switch device Q2 may be connected to a second end of the first switch device Q1, and a second end of the second switch device Q2 may be connected to a ground GND_S2, wherein a voltage of the ground GND_S2 may be a fixed value, for example, 0V.

[0060] Furthermore, during the on-time of the second switch device Q2, the first switch device Q1 is turned off to ensure that the voltage of the floating ground GND_S1 can be pulled down to the ground or the first voltage. During the on-time of the first switch device Q1, the second switch device Q2 is turned off to ensure that the voltage of the floating ground GND_S1 can be raised to the second voltage. The second voltage is a very high voltage relative to the first voltage.

[0061] In some specific embodiments, Figure 2 As shown, the above-mentioned bootstrap drive circuit 100 may also include a second isolation circuit 105, which is configured to isolate and transmit the second control signal PWM2 to the second drive circuit 104, and the second drive circuit 104 may be specifically configured to control the second switching device Q2 to periodically turn on and off according to the received second control signal PWM2, so that the high-voltage-resistant second isolation circuit 105 can be used to further improve the withstand voltage value of the bootstrap drive circuit 100, so that the bootstrap drive circuit 100 can better meet the needs of high-voltage application scenarios.

[0062] The second isolation circuit 105 may include a digital isolator (e.g., a digital isolation chip), and the digital isolator may receive a second control signal PWM2 sent by the control device, and isolate and transmit the received second control signal PWM2 to the second drive circuit 104. The second control signal PWM2 may be a pulse width modulated signal, and its high level and low level may drive the second switch device Q2 to turn on and off, respectively.

[0063] In some examples, the second switching device Q2 may be a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), and the first end of the second switching device Q2 may be one of the source and the drain of the second switching device Q2, and the second end of the second switching device Q2 may be the other of the source and the drain of the second switching device Q2.

[0064] Furthermore, the second drive circuit 104 can be specifically configured to transmit the received second control signal PWM2 to the control terminal of the second switch device Q2 to control the second switch device Q2 to periodically turn on and off. The connection point SW of the first end of the second switch device Q2 and the second end of the first switch device Q1 can be used as a floating potential reference point, and the voltage VIN and the ground GND_S2 can be the power supply voltage +BUS and the ground voltage BUS_GND (for example, 0V) of the bus, respectively. In some examples, the ground GND_S2 and the ground voltage BUS_GND of the bus can be connected internally through the second switch device Q2.

[0065] In some specific embodiments, Figure 3As shown, the first control signal PWM1 and the second control signal PWM2 can both be pulse width modulation signals, and the phase difference between the first control signal PWM1 and the second control signal PWM2 can be 180 degrees to ensure that the first switch device Q1 is turned off during the turn-on period of the second switch device Q2, and to ensure that the first switch device Q1 is turned on during the turn-off period of the second switch device Q2.

[0066] In some embodiments, the bootstrap driving circuit 100 may further include a digital controller (not shown in the figure), which is configured to send a first control signal PWM1 and a second control signal PWM2 to the first isolation circuit 101 and the second isolation circuit 104 respectively.

[0067] In some examples, the digital controller may include a digital signal processor (DSP), for example, a digital control chip, wherein the digital control chip may be configured to generate a first control signal PWM1 and a second control signal PWM2, and send the generated first control signal PWM1 and the second control signal PWM2 to the first isolation circuit 101 and the second isolation circuit 104, respectively.

[0068] In some embodiments, the bootstrap driving circuit 100 may further include a rectifying circuit configured to convert a voltage at the second end of the first switching device Q1 (ie, a voltage of the floating ground GND_S1 ) into a voltage for driving an external load to operate.

[0069] In some examples, such as Figure 4 As shown, the rectifier circuit can be a transformer step-down rectifier circuit, and can include a transformer T1, a first diode D11, a second diode D12, a third diode D13, a fourth diode D14 and a first capacitor C11. Among them, the first input end of the transformer T1 is connected to the connection point SW, the connection point SW is the connection point of the second end of the first switch device Q1 and the first end of the second switch device Q2, the second input end of the transformer T1 is grounded BUS_GND, the first output end of the transformer T1 is connected to the positive electrode of the first diode D11, the negative electrode of the first diode D11 is connected to the negative electrode of the second diode D12 and one end of the first capacitor C11, the positive electrode of the second diode D12 is connected to the second output end of the transformer T1 and the negative electrode of the third diode D13, the positive electrode of the third diode D13, the positive electrode of the fourth diode D14 and the other end of the first capacitor C11 can be grounded GND, and the negative electrode of the fourth diode D14 is connected to the positive electrode of the first diode D11.

[0070] Furthermore, the rectifier circuit 106 can provide a first output voltage VOUT and a second output voltage to an external load, and the first output voltage VOUT and the second output voltage are voltages across the first capacitor respectively, wherein the second output voltage is the voltage of the ground GND, for example, can be 0V.

[0071] Specifically, in the above-mentioned rectifier circuit, the first diode D11, the second diode D12, the third diode D13 and the fourth diode D14 can form a rectifier bridge, and the voltage at the second end of the first switching device Q1 is successively stepped down by the transformer T1, rectified by the rectifier bridge composed of four diodes and filtered by the first capacitor C11. The obtained voltage VOUT can be considered as a specified voltage that can drive the external load to work normally.

[0072] In some examples, such as Figure 2 and Figure 4 As shown, in an embodiment where the bootstrap drive circuit 100 includes a first isolation circuit 101, a bootstrap circuit 102, a first drive circuit 103, a first switching device Q1, a second drive circuit 104, a second switching device Q2, a second isolation circuit 105 and a digital controller, the first isolation circuit 101 may include a digital isolation chip U7, the second isolation circuit 105 may include a digital isolation chip U8, and the digital controller may be connected to an input port INB of the digital isolation chip U7 and an input port INB of the digital isolation chip U8, so that the first control signal PWM1 and the second control signal PWM2 generated when the digital controller is working can be input into the digital isolation chip U7 and the digital isolation chip U8 through the input port INB of the digital isolation chip U7 and the input port INB of the digital isolation chip U8, respectively.

[0073] Specifically, the first driving circuit 103 may include a driving chip U1, the second driving circuit 104 may include a driving chip U2, and the first end of the bootstrap capacitor C62 in the bootstrap circuit 102 may be connected to the input port VIN of the driving chip U1, so that the first end voltage of the bootstrap capacitor C62 in the bootstrap circuit 102 can drive the driving chip U1 to work. The input port VIN of the driving chip U2 can be connected to a second preset voltage (for example, 12V), and the second preset voltage can drive the driving chip U2 to work.

[0074] Specifically, the digital isolation chip U7 can output the first control signal PWM1 to the input port PWM of the driver chip U1 through its output port OUTB, and the digital isolation chip U8 can output the second control signal PWM2 to the input port PWM of the driver chip U2 through its output port OUTB. In addition, the driver chip U1 can output the first control signal PWM1 to the control end of the first switch device Q1 through the output port OUTH and the output port OUTL to achieve the switching effect of driving the first switch device Q1. The driver chip U2 can output the second control signal PWM2 to the control end of the second switch device Q2 through the output port OUTH and the output port OUTL to achieve the switching effect of driving the second switch device Q2.

[0075] From the above, it can be seen that the bootstrap drive circuit provided in this embodiment utilizes the first isolation circuit to isolate and transmit the first control signal to the first drive circuit, and utilizes the bootstrap circuit to drive the first drive circuit to work, and when the first drive circuit is working, it can control the first switching device to periodically open and close according to the first control signal, so that the power device and the control device can be isolated by utilizing the high-voltage resistant isolation circuit to reduce the influence of the high voltage on the power device side on the control device that is not resistant to high voltage, thereby achieving the high-voltage resistant performance of the bootstrap drive circuit to meet the needs of high-voltage application scenarios and expand the scope of application.

[0076] See also Figure 5 , Figure 5 Schematic diagram of the structure of the switching power supply provided in the embodiment of the present application. Figure 5 As shown, the switching power supply 200 may include the bootstrap driving circuit 201 of any of the above embodiments.

[0077] The bootstrap drive circuit 201 may include a first isolation circuit, a bootstrap circuit, a first drive circuit and a first switch device. The first isolation circuit is configured to isolate and transmit the first control signal to the first drive circuit. The bootstrap circuit is configured to drive the first drive circuit to work. The first drive circuit is configured to control the first switch device to be periodically turned on and off according to the first control signal when working.

[0078] In some examples, the switching power supply 200 may convert a voltage input from an external power source into a specified output voltage to supply power to an external load.

[0079] It should be noted that the switching power supply provided in the embodiment of the present application, since the bootstrap drive circuit provided in the embodiment of the present application is provided, can achieve the beneficial effects that can be achieved by any bootstrap drive circuit provided in the embodiment of the present application. Please refer to the previous embodiments for details, which will not be repeated here.

[0080] The above is a detailed introduction to a bootstrap drive circuit and a switching power supply provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, according to the ideas of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A bootstrap driving circuit, characterized in that: include: A first isolation circuit, a bootstrap circuit, a first drive circuit and a first switching device, wherein: The first isolation circuit is configured to isolate and transmit the first control signal to the first driving circuit; The bootstrap circuit is configured to drive the first driving circuit to operate; The first driving circuit is configured to control the first switching device to be periodically turned on and off according to the first control signal during operation.

2. The bootstrap driving circuit according to claim 1, characterized in that: The first terminal of the first switching device is configured to be connected to an external power source, the voltage of the second terminal of the first switching device is a floating voltage, and the first switching device is configured to drive an external load.

3. The bootstrap driving circuit according to claim 2, characterized in that: The bootstrap circuit includes a bootstrap diode and a bootstrap capacitor, the anode of the bootstrap diode is connected to the first power supply voltage, the cathode of the bootstrap diode is connected to the first end of the bootstrap capacitor, the second end of the bootstrap capacitor is connected to the floating ground, and the voltage at the first end of the bootstrap capacitor is configured to drive the first drive circuit to operate.

4. The bootstrap driving circuit according to claim 2, characterized in that: The bootstrap drive circuit also includes: a second drive circuit and a second switching device, wherein the second drive circuit is configured to control the second switching device to periodically turn on and off, and the second switching device is configured to pull the voltage of the second end of the first switching device down to the first voltage when turned on.

5. The bootstrap driving circuit according to claim 4, characterized in that: The first end of the second switching device is connected to the second end of the first switching device, and the second end of the second switching device is grounded.

6. The bootstrap driving circuit according to claim 4, characterized in that: The bootstrap drive circuit further includes: a second isolation circuit, wherein the second isolation circuit is configured to isolate and transmit a second control signal to the second drive circuit, and the second drive circuit is specifically configured to control the second switch device to periodically turn on and off according to the second control signal.

7. The bootstrap driving circuit according to claim 6, characterized in that: The first control signal and the second control signal are pulse width modulation signals, and a phase difference between the first control signal and the second control signal is 180 degrees.

8. The bootstrap driving circuit according to claim 6, characterized in that: The first isolation circuit and the second isolation circuit include digital isolators.

9. The bootstrap driving circuit according to claim 6, characterized in that: The bootstrap driving circuit further includes a digital controller configured to send the first control signal and the second control signal to the first isolation circuit and the second isolation circuit, respectively.

10. A switching power supply, characterized in that: The bootstrap driving circuit comprises the bootstrap driving circuit according to any one of claims 1 to 9.

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