A power converter and a switch control circuit

Abstract

The present application proposes a switch control circuit and a power converter including the switch control circuit. The power converter includes a high-side switch and a low-side switch connected in series. The switch control circuit is used to drive the high-side switch of the power converter. The switch control circuit has a first terminal for receiving a low-side switch drive signal, a second terminal used as a reference ground terminal of the switch control circuit, and a third terminal used as an output terminal to provide a high-side switch drive signal. The switch control circuit can obtain electrical energy from the low-side switch drive signal and does not require an internal voltage regulator that withstands high voltage. Since no high-voltage resistant device is required, the technical solution of the present application reduces the design complexity and cost of the switch control circuit.

Description

[0001] Related references

[0002] This application claims priority to and the benefits of patent application No. 17 / 541,576 filed in the United States on December 3, 2021, and incorporates the entire contents of the aforementioned patent application herein. Technical Field

[0003] The present application relates to an electronic circuit, and more particularly, to a switch control circuit for driving a switching power supply and a power converter including the switch control circuit. Background Art

[0004] like Figure 1 and Figure 2 The example circuit for the half-bridge circuit 11 ( Figure 1 ) and 21( Figure 2 ) of conventional gate drivers (e.g. Figure 1 The high-side gate driver 12 and the low-side gate driver 13 in the control IC (e.g. Figure 2 The controller 22 in each requires its own power supply circuit. Figure 1 The half-bridge circuit 11 and Figure 2 The half-bridge circuit 21 in FIG. 2 is shown as including a high-side power transistor QH and a low-side power transistor QL connected in series. Usually, in particular, in order to drive the high-side power transistor QH, a bootstrap circuit (for example, including a bootstrap diode DB and a bootstrap capacitor CB) is required to generate a bootstrap voltage VB, and the bootstrap circuit should be powered by an auxiliary voltage VP, which is usually generated by charging the capacitor Caux from the auxiliary winding Laux of the transformer T through a diode Daux. The auxiliary voltage VP or the bootstrap voltage VB usually needs to be supplied by a gate driver (for example Figure 1 12 and 13) in the internal voltage regulator (such as LDO, etc.) or control IC (such as Figure 2 22) to a lower internal supply voltage VDD to power other internal circuits (such as logic control circuits, etc.). In addition, additional pins or circuits (such as Figure 1 The synchronization pin SYNC of the middle and high side gate driver 12 and the synchronization pin SYNC of the low side gate driver 13, Figure 1 The synchronization circuit inside the middle and high side gate driver 12 and Figure 2 The synchronous circuit HV SYNC in the gate driver realizes the synchronous communication between the high-side gate drive signal VGH for driving the high-side power tube QH and the low-side gate drive signal VGL for driving the low-side power tube QL. Moreover, in most AC-DC applications, the voltage regulator and synchronous circuit inside the gate driver need to withstand high voltages (e.g., up to 100V or higher), which increases the design complexity and cost. Summary of the invention

[0005] An embodiment of the present application relates to a power converter, comprising: a high-side switch having a first end, a second end and a control end, the first end of the high-side switch being coupled to an input port of the power converter; a low-side switch having a first end, a second end and a control end, the first end of the low-side switch being coupled to the second end of the high-side switch to form a common coupling point, and the second end of the low-side switch being coupled to a reference ground of the power converter; and a high-side switch control circuit having a first terminal, a second terminal and a third terminal, the first terminal of which is configured to receive a low-side switch drive signal, the low-side switch drive signal being provided to the control end of the low-side switch, the second terminal of which is coupled to the common coupling point, and the third terminal of which is configured to provide a high-side switch drive signal, and the high-side switch control circuit is configured to obtain electrical energy from the low-side switch drive signal.

[0006] According to an embodiment of the present application, the high-side switch control circuit is further used to determine whether the low-side switch is turned on according to the low-side switch driving signal.

[0007] According to an embodiment of the present application, the high-side switch control circuit is further configured to keep the high-side switch turned off once it is detected that the low-side switch is turned on.

[0008] According to an embodiment of the present application, the high-side switch control circuit is further configured to allow the high-side switch to switch between on and off once it is detected that the low-side switch is turned off.

[0009] According to an embodiment of the present application, the high-side switch control circuit is integrated on a first semiconductor die or packaged in a first integrated circuit chip.

[0010] According to one embodiment of the present application, the high-side switch control circuit further includes: a fourth terminal configured to provide an adjusted voltage signal when the capacitive energy storage device is coupled between the fourth terminal and the second terminal of the high-side switch control circuit.

[0011] According to one embodiment of the present application, the high-side switch control circuit also includes: an internal adjustment module, coupled between the first terminal and the fourth terminal of the high-side switch control circuit, and used to convert the low-side switch drive signal into an adjusted voltage signal when the capacitive energy storage device is coupled between the fourth terminal and the second terminal of the high-side switch control circuit.

[0012] According to one embodiment of the present application, the high-side switch control circuit also includes: a synchronous control module, coupled to the first terminal of the high-side switch control circuit, and used to generate a synchronous control signal based on the low-side switch drive signal, the synchronous control signal having a first logic level indicating that the low-side switch is turned on and a second logic level indicating that the low-side switch is turned off.

[0013] One embodiment of the present application also relates to a switch control circuit used in a power converter. The switch control circuit includes: a first terminal for receiving a low-side switch drive signal; a second terminal configured as a reference ground terminal of the switch control circuit; and a third terminal configured as an output terminal of the switch control circuit for providing a high-side switch drive signal; the switch control circuit is configured to receive the low-side switch drive signal at the first terminal.

[0014] According to one embodiment of the present application, the switch control circuit is configured to use the potential at the second terminal of the high-side switch control circuit as a reference, and when the low-side switch drive signal is higher than a preset threshold, keep the high-side switch drive signal in a reset logic state; and use the potential at the second terminal of the high-side switch control circuit as a reference, and when the low-side switch drive signal is lower than a preset threshold, allow the high-side switch drive signal to switch between a reset logic state and a set logic state.

[0015] According to one embodiment of the present application, the switch control circuit is integrated on a semiconductor die or packaged in an integrated circuit chip.

[0016] According to an embodiment of the present application, the switch control circuit further includes: a fourth terminal configured to provide an adjusted voltage signal when the capacitive energy storage device is coupled between the fourth terminal and the second terminal of the switch control circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following drawings are helpful to better understand the following description of different embodiments of the present application. These drawings are not drawn according to actual features, sizes and proportions, but schematically illustrate the main features of some embodiments of the present application. These drawings and embodiments provide some embodiments of the present application in a non-limiting and non-exhaustive manner. For the sake of simplicity, the same or similar components or structures having the same functions in different drawings are marked with the same reference numerals.

[0018] Figure 1 A circuit structure diagram of a conventional flyback converter 10 is shown.

[0019] Figure 2 is a schematic diagram of a circuit structure of a conventional LLC converter 20 .

[0020] Figure 3A power converter 100 according to an embodiment of the present application is illustrated.

[0021] Figure 4 A power converter 200 according to an embodiment of the present application is illustrated.

[0022] Figure 5 A power converter 300 according to an embodiment of the present application is illustrated.

[0023] Figure 6 A power converter 400 according to an embodiment of the present application is illustrated.

[0024] Figure 7 The internal adjustment module 721 according to an embodiment of the present application is illustrated.

[0025] Figure 8 An internal adjustment module 821 according to a variant embodiment of the present application is illustrated.

[0026] Fig. 9 The synchronous control module 922 according to an embodiment of the present application is illustrated.

[0027] Fig.10 The synchronous control module 1022 according to a variant embodiment of the present application is illustrated. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present application illustrated in the accompanying drawings will now be described in detail. Although the present application will be described in conjunction with the preferred embodiments, it should be understood that they are not intended to limit the present application to these embodiments. On the contrary, the present application is intended to cover substitutions, modifications and equivalents that may be included in the spirit and scope of the present application as defined by the appended claims. In addition, in the following detailed description of the present application, many specific details are set forth in order to provide a thorough understanding of the present application. However, it is apparent to a person of ordinary skill in the art that the technical solutions of the present application can be implemented without these specific details. In order to avoid unnecessarily obscuring the present application, known methods, processes, components and circuits are not described in detail here.

[0029] An "embodiment" or "example" means that certain features, structures, or characteristics are included in at least one embodiment of the present application. These "embodiments" or "examples" do not necessarily refer to the same embodiment. In addition, features, structures, or characteristics may be combined in one or more embodiments. In addition, the drawings are provided for illustration purposes and are not necessarily drawn to scale. When an element is described as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or one or more intermediate elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, it means that there are no intermediate elements.

[0030] Figure 3 The power converter 100 according to an embodiment of the present application is illustrated. The power converter 100 may include a half-bridge switch circuit 110, which includes a high-side switch QH and a low-side switch QL. The high-side switch QH may have a first end, a second end, and a control end, wherein the first end of the high-side switch QH may be coupled to the input port VIN of the power converter 100. The low-side switch QL also has a first end, a second end, and a control end, wherein the first end of the low-side switch QL is coupled to the second end of the high-side switch QH to form a common coupling point SW, and the second end of the low-side switch QL is coupled to the reference ground (PGND) of the power converter 100.

[0031] The power converter 100 may further include a switch driving module 101, which is configured to drive the half-bridge switch circuit 110. The switch driving module 101 may include a high-side switch control circuit 120 to control the high-side switch QH. The high-side switch control circuit 120 may include a first terminal T1, which is configured to receive a low-side switch drive signal VGL for driving the low-side switch QL; a second terminal T2, which is configured as a reference ground terminal of the high-side switch control circuit 120; and a third terminal T3, which is configured as an output terminal of the high-side switch control circuit 120 to provide a high-side switch drive signal VGH. The second terminal T2 of the high-side switch control circuit 120 may be coupled to a common coupling point SW. The high-side switch drive signal VGH may have a reset logic state (e.g., logic low) that drives the high-side switch QH off and a set logic state (e.g., logic high) that drives the high-side switch QH on. The high-side switch control circuit 120 may be configured to obtain electrical energy from the low-side switch drive signal VGL. Since the low-side switch drive signal VGL generally has a well-adjusted voltage amplitude, for example, in the range of 10V to 20V, relative to the reference ground PGND of the power converter 100, the high-side switch control circuit 120 that can be configured to obtain electrical energy from the low-side switch drive signal VGL according to various embodiments of the present application may not need to be provided with an internal voltage regulator that can withstand high voltage. The "high voltage" here may refer to a voltage higher than the voltage amplitude (for example, 10V to 20V) of the low-side switch drive signal VGL in one example, may refer to a voltage higher than 20V to 100V in another example, or may refer to a voltage higher than 100V to 1500V in another example. Since no high-voltage resistant devices are required, the present application reduces the complexity and cost of the switch controller design.

[0032] According to an embodiment of the present application, the high-side switch control circuit 120 may be further configured to realize synchronous communication of high-side switch control and low-voltage side switch control through the first terminal T1. The synchronous communication of high-side switch control and low-voltage side switch control is essential to prevent the high-side switch QH and the low-side switch QL from being turned on at the same time. The high-side switch control circuit 120 may be configured to detect whether the low-side switch is turned on or off based on the low-side switch drive signal VGL received at the first terminal T1. Therefore, according to the high-side switch control circuit 120 in each embodiment of the present application, a single terminal T1 may be used as its power supply terminal to obtain energy, and at the same time as its synchronization / communication terminal to realize synchronous communication of high-side switch control and low-voltage side switch control. Compared with traditional gate drivers (for example, which require two independent terminals to be set for providing power supply and synchronous control, respectively), Figure 1 Compared with the gate driver 12 in the embodiment of the present invention, the high-side switch control circuit 120 according to each embodiment of the present application can save at least one I / O terminal / pad when integrated on a semiconductor bare die / wafer / die, and can save at least one pin when packaged in an integrated circuit chip, thereby helping to save cost and size.

[0033] According to one embodiment of the present application, the high-side switch control circuit 120 may be further configured to use the potential VSS at the second terminal T2 of the high-side switch control circuit 120 as a reference, and when the low-side switch drive signal VGL is higher than the preset threshold value Vth, it is determined that the low-side switch QL is turned on. In an exemplary embodiment, the preset threshold value Vth may be zero volts. In another alternative exemplary embodiment, the preset threshold value Vth may be a voltage value higher than zero volts (e.g., 0.5V or 1V or other suitable values) to improve noise immunity. The high-side switch control circuit 120 may also be configured to use the potential VSS at the second terminal T2 of the high-side switch control circuit 120 as a reference, and when the low-side switch drive signal VGL is lower than the preset threshold value Vth, it is determined that the low-side switch QL has been detected to be disconnected. The high-side switch control circuit 120 may also be configured to lock / maintain the high-side switch drive signal VGH in a reset logic state (e.g., logic low) to keep the high-side switch QH disconnected when it detects that the low-side switch QL is turned on (i.e., with the potential VSS at the second terminal T2 of the high-side switch control circuit as a reference, when the low-side switch drive signal VGL is higher than a preset threshold value Vth). The high-side switch control circuit 120 may also be configured to allow the high-side switch drive signal VGH to switch between a reset logic state (e.g., logic low) and a set logic state (e.g., logic high) when it detects that the low-side switch QL is disconnected (i.e., with the potential VSS at the second terminal T2 of the high-side switch control circuit as a reference, when the low-side switch drive signal is lower than a preset threshold value Vth).

[0034] According to an exemplary embodiment of the present application, the high-side switch control circuit 120 may further include a fourth terminal T4 configured to provide an adjusted voltage signal VB when the capacitive energy storage device CB is coupled between the fourth terminal T4 and the second terminal T2 of the high-side switch control circuit 120 .

[0035] According to an exemplary embodiment of the present application, the high-side switch control circuit 120 may further include an internal adjustment module 121, which is coupled between the first terminal T1 and the fourth terminal T4 of the high-side switch control circuit 120. The internal adjustment module 121 may be configured to convert the low-side switch drive signal VGL into the adjusted voltage signal VB when the capacitive energy storage device CB is coupled between the fourth terminal T4 and the second terminal T2 of the high-side switch control circuit 120. Since the low-side switch drive signal VGL generally has a well-regulated voltage amplitude, for example, in the range of 10V to 20V relative to the reference ground PGND of the power converter 100, the high-side switch control circuit 120 may not require its internal adjustment module 121 to withstand high voltage. Here, "high voltage" may refer to a voltage higher than the low-side switch drive signal VGL (e.g., 10V to 20V) in one example, may refer to a voltage even higher than 20V to 100V in another example, or may refer to a voltage higher than 100V to 1500V in another example. For example, the internal regulation module 121 may include a low voltage device (eg, having a breakdown voltage lower than the voltage of the low-side switch drive signal VGL). Figure 4 In the exemplary embodiment shown, the internal regulation module 121 of the power converter 200 may simply include a rectifier (e.g., a MOSFET or a diode) configured to conduct in the direction from the first terminal T1 to the fourth terminal T4 and reversely block (not conduct) in the direction from the fourth terminal T4 to the first terminal T1. Except for the internal regulation module 121, the other circuits and elements in the power converter 200 are the same as those in the power converter 100, so they are not described in detail. Low-voltage devices not only save cost and size, but also help reduce design complexity and power consumption.

[0036] According to an exemplary embodiment of the present application, the high-side switch control circuit 120 may further include a synchronous control module 122, which is coupled to the first terminal T1 of the high-side switch control circuit 120 and is configured to generate a synchronous control signal SN based on the low-side switch drive signal VGL, wherein the synchronous control signal SN has a first logic level (e.g., logic high) indicating that the low-side switch QL is turned on and a second logic level (e.g., logic low) indicating that the low-side switch QL is turned off. Since the low-side switch drive signal VGL generally has a well-regulated voltage amplitude, for example, in the range of 10V to 20V, relative to the reference ground PGND of the power converter 100, the high-side switch control circuit 120 may not require its synchronous control module 122 to be able to withstand high voltage. Here, "high voltage" may refer to a voltage higher than the voltage amplitude (e.g., 10V to 20V) of the low-side switch drive signal VGL in one example, may refer to a voltage even higher than 20V to 100V in another example, or may refer to a voltage higher than 100V to 1500V in another example. For example, the synchronous control module 122 may be composed of low-voltage devices. Low voltage devices not only save cost and size, but also help reduce design complexity and power consumption.

[0037] According to an exemplary embodiment of the present application, the high-side switch control circuit 120 may further include a synchronous control module 122, which is coupled to the first terminal T1 of the high-side switch control circuit 120 and is configured to generate a synchronous control signal SN based on the low-side switch drive signal VGL, wherein the synchronous control signal SN has a first logic level (e.g., logic high) indicating that the low-side switch QL is turned on and a second logic level (e.g., logic low) indicating that the low-side switch QL is turned off. Since the low-side switch drive signal VGL generally has a well-regulated voltage amplitude, for example, in the range of 10V to 20V, relative to the reference ground PGND of the power converter 100, the high-side switch control circuit 120 may not require its synchronous control module 122 to be able to withstand high voltage. Here, "high voltage" may refer to a voltage higher than the low-side switch drive signal VGL (e.g., 10V to 20V) in one example, may refer to a voltage even higher than 20V to 100V in another example, and may refer to a voltage higher than 100V to 1500V in another example. For example, the synchronous control module 122 may be composed of low-voltage devices. Low voltage devices not only save cost and size, but also help reduce design complexity and power consumption.

[0038] According to an exemplary embodiment of the present application, the high-side switch control circuit 120 may further include a logic control module 123 and a driver 124. In one example, the logic control module 123 and the driver 124 may be powered by the adjusted voltage signal VB from the internal regulation module 121. The logic control module 123 may be configured to receive at least the synchronization control signal SN, and further configured to provide a control signal DR to the driver 124 based at least in part on the synchronization control signal SN. The driver 124 may be configured to enhance the driving capability of the control signal DR to provide the high-side switch drive signal VGH. For example, the logic control module 123 may be configured to set the control signal DR to a logic low when the synchronization control signal SN is at a first logic level (e.g., logic high) indicating that the low-side switch is turned on, so as to lock the high-side switch drive signal VGH in a reset state (e.g., logic low), thereby keeping the high-side switch turned off. The logic control module 123 can also be configured to allow the control signal DR to switch between logic high and logic low according to other signals input to the logic control module 123 (e.g., current sensing signal VCS indicating current flowing through the high-side switch QH) when the synchronization control signal SN is at a second logic level (e.g., logic low) indicating that the low-side switch is turned off, thereby allowing the high-side switch drive signal VGH to switch between a set logic state (e.g., logic high) and a reset logic state (e.g., logic low) to allow the high-side switch QH to perform switching between on and off.

[0039] According to an exemplary embodiment of the present application, the switch driving module 101 may further include a low-side switch control circuit 130 to control the low-side switch QL. The low-side switch control circuit 130 may have a first terminal SP configured to receive a power supply voltage VP, a second terminal GND connected to a reference ground PGND of the power converter 100, and a third terminal GL configured to provide a low-side switch drive signal VGL.

[0040] According to an exemplary embodiment of the present application, the power converter 100 may further include an inductive energy storage device T, which Figure 3 In the example of , a transformer having a primary winding Lp and a secondary winding Ls is illustrated. The primary winding Lp can be coupled between the input port VIN of the power converter 100 and the common coupling point SW. Llk illustratively represents the leakage inductance of the transformer T. The secondary winding Ls has a first end and a second end, the first end can be coupled to the output terminal Vo of the power converter 100 through a synchronous rectifier SR (for example, including a MOSFET), and the second end can be coupled to the secondary reference ground SGND of the secondary side of the power converter 100. The output capacitive energy storage device Co can be coupled between the output terminal Vo of the power converter 100 and the secondary reference ground SGND. In Figure 3In an exemplary embodiment of the present invention, the power converter 100 has a flyback converter topology. The supply voltage VP for supplying power to the low-side switch control circuit 130 may be generated by an auxiliary winding Laux of a transformer T, which is inductively coupled to a primary winding Lp and a secondary winding Ls of the transformer T. A diode Daux and a capacitor Caux may be coupled between a first terminal and a second terminal of the auxiliary winding Laux, and a voltage across the capacitor Caux may be provided as the supply voltage VP.

[0041] In the aforementioned embodiments, a power converter (e.g., 100 or 200) configured in a flyback converter topology is taken as an example, and the flyback converter topology includes a high-side switch control circuit (e.g., 120) for driving a high-side switch (e.g., QH) of a half-bridge switch circuit (e.g., 110). However, it will be understood by those skilled in the art that the high-side switch control circuit according to various embodiments of the present application is also applicable to other power converters of different topologies. Figure 5 A power converter 300 according to an alternative embodiment of the present application is schematically shown. The power converter 300 may include a half-bridge switch circuit 210, which includes a high-side switch QH and a low-side switch QL. The high-side switch QH may have a first end, a second end, and a control end, wherein the first end of the high-side switch QH may be coupled to an input port VIN of the power converter 300. The low-side switch QL may also have a first end, a second end, and a control end, wherein the first end of the low-side switch QL may be coupled to the second end of the high-side switch QH to form a common coupling point SW, and the second end of the low-side switch QL may be coupled to a reference ground (PGND) or a current sensing pin CS of the power converter 300.

[0042] The power converter 300 may further include a switch driving module 201, which is configured to drive a half-bridge switch circuit 210. Similar to the switch driving module 101, the switch driving module 201 may include a high-side switch control circuit 220 to control the high-side switch QH. The high-side switch control circuit 220 includes a first terminal T1, a second terminal T2, and a third terminal T3. Wherein the first terminal T1 is configured to receive a low-side switch drive signal VGL, the second terminal T2 is configured as a reference ground terminal of the high-side switch control circuit 220, and the third terminal T3 is configured as an output terminal of the high-side switch control circuit 220 to provide a high-side switch drive signal VGH. The second terminal T2 of the high-side switch control circuit 220 may be coupled to a common coupling point SW. The high-side switch drive signal VGH may have a reset logic state (e.g., logic low) that drives the high-side switch QH to turn off and a set logic state (e.g., logic high) that drives the high-side switch QH to turn on. The high-side switch control circuit 220 may be configured to obtain electrical energy from the low-side switch drive signal VGL. Since the low-side switch drive signal VGL generally has a well-adjusted voltage value, for example, in the range of 10V to 20V, relative to the reference ground PGND of the power converter 300, the high-side switch control circuit 220 that can be configured to obtain electrical energy from the low-side switch drive signal VGL according to various embodiments of the present disclosure may not need to be provided with an internal voltage regulator that can withstand high voltages. The "high voltage" here may refer to a voltage higher than the low-side switch drive signal VGL (for example, 10V to 20V) in one example, may refer to a voltage even higher than 20V to 100V in another example, or may refer to a voltage higher than 100V to 1500V in another example. Since no high-voltage resistant devices are required, the present application reduces the complexity and cost of the switch controller design.

[0043] The high-side switch control circuit 220 may be further configured to implement synchronous communication of the high-side switch control and the low-side switch control through the first terminal T1. The synchronous communication of the high-side switch control and the low-side switch control is essential to prevent the high-side switch QH and the low-side switch QL from being turned on at the same time. The high-side switch control circuit 220 may be configured to detect whether the low-side switch is turned on or off based on the low-side switch drive signal VGL received at the first terminal T1. Therefore, the high-side switch control circuit 220 according to multiple embodiments of the present application may use a single terminal T1 as its power terminal to obtain energy, and at the same time as its synchronization / communication terminal to implement synchronous communication of the high-side switch control and the low-side switch control. This is different from conventional gate drivers (for example, which require two independent terminals to be set for providing power and synchronous control, respectively) Figure 2Compared with the controller 22 in FIG. 1 , the high-side switch control circuit 220 can save at least one I / O terminal / pad when integrated on a semiconductor die, and can save at least one pin when packaged in an integrated circuit chip. This can save cost and size.

[0044] According to an embodiment of the present application, the high-side switch control circuit 220 may be further configured to use the potential at the second terminal T2 of the high-side switch control circuit 220 (also labeled as VSS for simplicity) as a reference, and when the low-side switch drive signal VGL is higher than the preset threshold value Vth, it is determined that it has detected that the low-side switch QL is turned on. In an exemplary embodiment, the preset threshold value Vth may be zero volts. In an alternative exemplary embodiment, the preset threshold value Vth may be a voltage value higher than zero volts (e.g., 0.5V or 1V or other suitable values) to improve noise resistance. The high-side switch control circuit 220 may also be configured to use the potential VSS at the second terminal T2 of the high-side switch control circuit 220 as a reference, and when the low-side switch drive signal VGL is lower than the preset threshold value Vth, it is determined that it has detected that the low-side switch QL is disconnected. The high-side switch control circuit 220 may also be configured to lock / maintain the high-side switch drive signal VGH in a reset logic state (e.g., logic low) to keep the high-side switch QH turned off when it detects that the low-side switch QL is turned on (i.e., with the potential VSS at the second terminal T2 as a reference, when the low-side switch drive signal VGL is higher than a predetermined threshold value Vth). The high-side switch control circuit 220 may also be configured to allow the high-side switch drive signal VGH to switch between a reset logic state (e.g., logic low) and a set logic state (e.g., logic high) when it detects that the low-side switch QL is turned off (i.e., with the potential VSS at the second terminal T2 as a reference, when the low-side switch drive signal is lower than a preset threshold value Vth).

[0045] According to an exemplary embodiment of the present application, the high-side switch control circuit 220 may further include a fourth terminal T4 configured to provide an adjusted voltage signal VB when the capacitive energy storage device CB is coupled between the fourth terminal T4 and the second terminal T2 of the high-side switch control circuit 220 .

[0046] According to an exemplary embodiment of the present application, the high-side switch control circuit 220 may further include an internal regulation module 221, which is coupled between the first terminal T1 and the fourth terminal T4 of the high-side switch control circuit 220. The internal regulation module 221 may be configured to convert the low-side switch drive signal VGL into a regulation voltage signal VB when the capacitive energy storage device CB is coupled between the fourth terminal T4 and the second terminal T2 of the high-side switch control circuit 220. Since the low-side switch drive signal VGL generally has a well-regulated voltage value, for example, in the range of 10V to 20V relative to the reference ground PGND of the power converter 300, the high-side switch control circuit 220 may not require its internal regulation module 221 to withstand high voltage. Here, "high voltage" may refer to a voltage higher than the low-side switch drive signal VGL (e.g., 10V to 20V) in one example, may refer to a voltage even higher than 20V to 100V in another example, or may refer to a voltage higher than 100V to 1500V in another example. For example, the internal regulation module 221 may include a low voltage device (eg, having a breakdown voltage lower than the voltage of the low side switch drive signal VGL). Figure 6 In the exemplary embodiment shown, the internal regulation module 221 of the power converter 400 may simply include a rectifier (e.g., a MOSFET or a diode) configured to conduct in the direction from the first terminal T1 to the fourth terminal T4 and reversely block (not conduct) in the direction from the fourth terminal T4 to the first terminal T1. Except for the internal regulation module 221, the other circuits and elements in the power converter 400 are the same as those in the power converter 300 and are not described in detail here. Low-voltage devices not only save cost and size, but also help reduce design complexity and power consumption.

[0047] According to an exemplary embodiment of the present application, the high-side switch control circuit 220 may further include a synchronous control module 222, which is coupled to the first terminal T1 of the high-side switch control circuit 220 and is configured to generate a synchronous control signal SN based on the low-side switch drive signal VGL, wherein the synchronous control signal SN has a first logic level (e.g., logic high) indicating that the low-side switch QL is turned on and a second logic level (e.g., logic low) indicating that the low-side switch QL is turned off. Since the low-side switch drive signal VGL generally has a well-regulated voltage value, for example, in the range of 10V to 20V, relative to the reference ground PGND of the power converter 300, the high-side switch control circuit 220 may not require its synchronous control module 222 to be able to withstand high voltage. Here, "high voltage" may refer to a voltage higher than the low-side switch drive signal VGL (e.g., 10V to 20V) in one example, may refer to a voltage even higher than 20V to 100V in another example, or may refer to a voltage higher than 100V to 1500V in another example. For example, the synchronous control module 222 may be composed of low-voltage devices. Low voltage devices not only save cost and size, but also help reduce design complexity and power consumption.

[0048] According to an exemplary embodiment of the present application, the high-side switch control circuit 220 may further include a logic control module 223 and a driver 224. In one example, the logic control module 223 and the driver 224 may be powered by the adjusted voltage signal VB from the internal regulation module 221. The logic control module 223 may be configured to receive at least the synchronization control signal SN, and further configured to provide a control signal DR to the driver 224 based at least in part on the synchronization control signal SN. The driver 224 may be configured to enhance the driving capability of the control signal DR to provide the high-side switch drive signal VGH. For example, the logic control module 223 may be configured to set the control signal DR to a logic low when the synchronization control signal SN is at a first logic level (e.g., logic high) indicating that the low-side switch is turned on, so as to lock the high-side switch drive signal VGH in a reset state (e.g., logic low), thereby keeping the high-side switch turned off. The logic control module 223 can also be configured to allow the control signal DR to switch between logic high and logic low according to other signals input to the logic control module 223, thereby allowing the high-side switch drive signal VGH to switch between a set logic state (e.g., logic high) and a reset logic state (e.g., logic low) so that when the synchronization control signal SN is at a second logic level (e.g., logic low) indicating that the low-side switch is turned off, the high-side switch QH is allowed to perform on and off switching.

[0049] According to an exemplary embodiment of the present application, the switch driving module 201 may further include a low-side switch control circuit 230 to control the low-side switch QL. The low-side switch control circuit 230 may have a first terminal SP configured to receive a power supply voltage VP, a second terminal GND connected to a reference ground PGND of the power converter 300, and a third terminal GL configured to provide a low-side switch drive signal VGL. Figure 5 In the example shown, the low-side switch control circuit 230 is shown to include a buck circuit 231, which is configured to convert the power supply voltage VP into a lower internal power supply voltage VDD. The low-side switch control circuit 230 may also include a drive control circuit 232 and a driver 233 for generating a low-side switch drive signal QL. The drive control circuit 232 and the driver 233 may be powered by the internal power supply voltage VDD.

[0050] According to an exemplary embodiment of the present application, the power converter 300 may further include an inductive energy storage device T, which is attached to Figure 5 In the example of , a transformer having a primary winding Lp, a first secondary winding Ls1, and a second secondary winding Ls2 is illustrated. The primary winding Lp may have a first terminal coupled to a common coupling point SW of a high-side switch QH and a low-side switch QL through a resonant inductor Lr, and a second terminal coupled to a reference ground PGND of the power converter 300 through a resonant capacitor Cr. A current sensing capacitor Cs and a current sensing resistor Rs may be coupled to the primary winding Lp to provide a current sensing signal VCS to a drive control circuit 232 of a low-side switch control circuit 230. The first secondary winding Ls1 may have a first terminal coupled to a secondary reference ground SGND of a secondary side of the power converter 300, and a second terminal coupled to an output terminal Vo of the power converter 300 through a first synchronous rectifier SR1 (e.g., including a MOSFET). The second secondary winding Ls2 may have a first terminal coupled to a secondary reference ground SGND of the secondary side of the power converter 300, and a second terminal coupled to the output terminal Vo of the power converter 300 through a second synchronous rectifier SR2 (e.g., including a MOSFET). The output capacitive energy storage device Co may be coupled between the output terminal Vo of the power converter 300 and the secondary reference ground SGND. Figure 5 In an exemplary embodiment of the present invention, the power converter 300 is shown as having an LLC converter topology. The power supply voltage VP for supplying the low-side switch control circuit 230 can be generated from an auxiliary winding Laux of a transformer T, which is inductively coupled to a primary winding Lp and first and second secondary windings Ls1 and Ls2 of the transformer T. A diode Daux and a capacitor Caux can be coupled between a first terminal and a second terminal of the auxiliary winding Laux, and a voltage across the capacitor Caux can be provided as the power supply voltage VP.

[0051] According to an exemplary embodiment of the present application, the first terminal T1 of the high-side switch control circuit 220 may be configured to receive the low-side switch drive signal VGL through a unidirectional conductive device DG (e.g., a diode or a MOSFET connected in a diode manner). The unidirectional conductive device DG may be conductive in a direction entering the first terminal T1 of the high-side switch control circuit 220 (e.g., from the outside of the high-side switch control circuit 220 toward the first terminal T1, e.g., in the direction of Figure 5 In the example, from the third terminal GL of the low-side switch control circuit 230 to the first terminal T1), and reverse blocking in the direction outward from the first terminal T1 of the high-side switch control circuit 220 (for example, from the first terminal T1 to the outside of the high-side switch control circuit 220, for example, in the attached Figure 5 In the example of the embodiment, from the first terminal T1 of the high-side switch control circuit 220 to the third terminal GL of the low-side switch control circuit 230). The unidirectional conductive device DG may have a reverse breakdown voltage higher than a preset voltage value, for example, the preset voltage value may be determined by the maximum voltage difference between the low-side switch drive signal VGL and the voltage potential VSS at the second terminal T2 of the high-side switch control circuit 220. For example, for a typical application, an input voltage of 380V is provided at the input terminal VIN of the power converter 300 and an output voltage of 20V is desired, the turns ratio between the primary winding Lp and the first secondary winding Ls1 is 4, and when the low-side switch is turned off, the maximum voltage difference between the low-side switch drive signal VGL and the voltage potential VSS at the second terminal T2 of the high-side switch control circuit 220 may reach 540V. Therefore, a unidirectional conductive device DG having a reverse breakdown voltage higher than 540V (e.g., 600V or 700V) may be reasonably selected to protect the high-side switch control circuit 220 from damage.

[0052] The advantages of various embodiments of the present application are not limited to the above content. After reading the complete detailed description and studying the drawings, the advantages of various embodiments of the present application will become more obvious.

[0053] Obviously, according to the above teachings, various modifications and changes can be made to the present application. Therefore, it should be understood that within the scope of the appended claims, the present application can be implemented in a manner different from that specifically described. For example, Figure 7The internal regulation module 721 according to an embodiment of the present application is schematically shown, which can be used as the internal regulation module 121 of the high-side switch control circuit 120 or the internal regulation module 221 of the high-side switch control circuit 220. The internal regulation module 721 may include a resistor 722, a bipolar transistor 723, and a Zener diode 724. When used as the internal regulation module 121, the resistor 722 has a first terminal coupled to the T1 end of the high-side switch control circuit 120 (or when used as the internal regulation module 221, the resistor 722 has a first terminal coupled to the T1 end of the high-side switch control circuit 220) and a second terminal coupled to the cathode of the Zener diode 724. When used as the internal regulation module 121, the bipolar transistor 723 has a first terminal coupled to the T1 end, a second terminal coupled to the T4 end of the high-side switch control circuit 120 (when used as the internal regulation module 221, the second terminal is coupled to the T4 end of the high-side switch control circuit 220) and a third terminal coupled to the cathode of the Zener diode 724. When used as internal regulation module 121 , the anode of the Zener diode is coupled to the T2 terminal of the high-side switch control circuit 120 (or when used as internal regulation module 221 , the anode of the Zener diode is coupled to the T2 terminal of the high-side switch control circuit 220 ).

[0054] For another example, Figure 8An internal regulation module 821 according to an alternative embodiment of the present application is schematically shown, which can be used as the internal regulation module 121 of the high-side switch control circuit 120 or the internal regulation module 221 of the high-side switch control circuit 220. The internal regulation module 821 may include a first resistor 822, a Zener diode 823, a second resistor 824, and a bipolar transistor 825. When the internal regulation module 821 is used as the internal regulation module 121, the first resistor 822 may be coupled between the first terminal T1 and the fourth terminal T4 of the high-side switch control circuit 120 (when the internal regulation module 821 is used as the internal regulation module 221, the first resistor 822 may be coupled between the first terminal T1 and the fourth terminal T4 of the high-side switch control circuit 220). When the internal regulation module 821 is used as the internal regulation module 121, the cathode of the Zener diode 823 may be coupled to the fourth terminal T4 of the high-side switch control circuit 120 (or when the internal regulation module 821 is used as the internal regulation module 221, the cathode is coupled to the fourth terminal T4 of the high-side switch control circuit 220), and the anode of the Zener diode 823 is coupled to the first terminal of the second resistor 824. When the internal regulation module 821 is used as the internal regulation module 121, the second terminal of the second resistor 824 is coupled to the second terminal T2 of the high-side switch control circuit 120 (or when the internal regulation module 821 is used as the internal regulation module 221, the second terminal of the second resistor 824 is coupled to the second terminal T2 of the high-side switch control circuit 220). When the internal regulation module 821 is used as the internal regulation module 121, the first terminal of the bipolar transistor 825 is coupled to the fourth terminal T4 of the high-side switch control circuit 120 (or when the internal regulation module 821 is used as the internal regulation module 221, the first terminal of the bipolar transistor 825 is coupled to the fourth terminal T4 of the high-side switch control circuit 220), the second terminal of the bipolar transistor 825 is coupled to the second terminal T2 of the high-side switch control circuit 120 (or when the internal regulation module 821 is used as the internal regulation module 221, the second terminal of the bipolar transistor 825 is coupled to the second terminal T2 of the high-side switch control circuit 220), and the third terminal of the bipolar transistor 825 is coupled to the anode of the Zener diode 823. The circuit elements in the exemplary internal regulation modules 721 and 821 are low voltage devices (e.g., having a breakdown voltage lower than the low-side switch drive signal VGL).

[0055] Fig. 9The synchronous control module 922 according to an embodiment of the present application is schematically illustrated, which can be used as the synchronous control module 122 of the high-side switch control circuit 120 or the synchronous control module 222 of the high-side switch control circuit 220. In this example, the synchronous control module 922 may include a comparator. When used as the synchronous control module 122, the comparator has a first input terminal (e.g., a non-inverting input terminal "+") and a second input terminal (e.g., an inverting input terminal "-"), wherein the first input terminal is coupled to the T1 terminal of the high-side switch control circuit 120 (or when used as the synchronous control module 222, coupled to the T1 terminal of the high-side switch control circuit 220), and the second input terminal is configured to receive a preset threshold value Vth (e.g., at Fig. 9 In the example of the embodiment, the second input terminal of the comparator is connected to the second terminal T2 of the high-side switch control circuit 120 or 220, so the preset threshold value Vth is zero volts relative to the potential VSS), and the comparator is configured to compare the low-side switch drive signal VGL received from the first terminal T1 with the preset threshold value Vth to provide a synchronization control signal SN at the output terminal of the comparator. The comparator can be composed of low-voltage devices.

[0056] Fig.10 The synchronous control module 1022 according to an alternative embodiment of the present application is schematically shown, which can be used as the synchronous control module 122 of the high-side switch control circuit 120 or the synchronous control module 222 of the high-side switch control circuit 220. The synchronous control module 1022 may include a Zener diode 1023, when used as the synchronous control module 122, its cathode is coupled to the first terminal T1 of the high-side switch control circuit 120 through a resistor element 1024 (or when used as the synchronous control module 222, it is coupled to the first terminal T1 of the high-side switch control circuit 220). When used as the synchronous control module 122, its anode is connected to the second terminal T2 of the high-side switch control circuit 120 (or when used as the synchronous control module 222, it is connected to the second terminal T2 of the high-side switch control circuit 220). The Zener diode 1023 is configured to provide a synchronization signal SN at the cathode. The synchronous control module 1022 is also composed of a low voltage element with a breakdown voltage lower than the voltage amplitude of the low-side switch drive signal VGL.

Claims

1. A power converter, comprising: A high-side switch having a first terminal, a second terminal and a control terminal, wherein the first terminal of the high-side switch is coupled to the input port of the power converter; A low-side switch having a first end, a second end and a control end, the first end of the low-side switch being coupled to the second end of the high-side switch to form a common coupling point, and the second end of the low-side switch being coupled to a reference ground of the power converter; as well as A high-side switch control circuit has a first terminal, a second terminal and a third terminal, wherein the first terminal is configured to receive a low-side switch drive signal, and the low-side switch drive signal is provided to the control end of the low-side switch, the second terminal is coupled to the common coupling point, and the third terminal is configured to provide the high-side switch drive signal, and the high-side switch control circuit is configured to obtain electrical energy from the low-side switch drive signal. 2 . The power converter as claimed in claim 1 , wherein the high-side switch control circuit is further configured to determine whether the low-side switch is turned on according to the low-side switch driving signal.

3. The power converter as claimed in claim 2, wherein the high-side switch control circuit is further configured to use the potential at the second terminal of the high-side switch control circuit as a reference, and when the low-side switch drive signal is higher than a preset threshold, determine that it has detected that the low-side switch is turned on.

4. The power converter as claimed in claim 3, wherein the high-side switch control circuit is further configured to use the potential at the second terminal of the high-side switch control circuit as a reference, and when the low-side switch drive signal is lower than a preset threshold, determine that it has detected that the low-side switch is turned off. 5 . The power converter of claim 2 , wherein the high-side switch control circuit is further configured to keep the high-side switch off upon detecting that the low-side switch is turned on. 6 . The power converter of claim 2 , wherein the high-side switch control circuit is further configured to allow the high-side switch to switch between on and off upon detecting that the low-side switch is turned off.

7. The power converter of claim 1, further comprising: A low-side switch control circuit is configured to provide a low-side switch drive signal.

8. The power converter as claimed in claim 7, wherein: The low-side switch control circuit has a first terminal configured to receive a power supply voltage, a second terminal connected to a reference ground of the power converter, and a third terminal configured to provide the low-side switch drive signal. 9 . The power converter of claim 1 , wherein the high-side switch control circuit is integrated on a first semiconductor die or packaged in a first integrated circuit chip.

10. The power converter of claim 1, wherein the high-side switch control circuit further comprises: A fourth terminal is configured to provide a regulated voltage signal when the capacitive energy storage device is coupled between the fourth terminal and the second terminal of the high-side switch control circuit.

11. The power converter of claim 10, wherein the high-side switch control circuit further comprises: The internal regulation module is coupled between the first terminal and the fourth terminal of the high-side switch control circuit and is used to convert the low-side switch drive signal into an adjusted voltage signal when the capacitive energy storage device is coupled between the fourth terminal and the second terminal of the high-side switch control circuit.

12. The power converter of claim 2, wherein the high-side switch control circuit further comprises: The synchronous control module is coupled to the first terminal of the high-side switch control circuit and is used to generate a synchronous control signal based on the low-side switch drive signal, wherein the synchronous control signal has a first logic level indicating that the low-side switch is turned on and a second logic level indicating that the low-side switch is turned off.

13. The power converter according to claim 12, wherein the synchronous control module comprises: A comparison circuit is configured to compare the low-side switch drive signal with a preset threshold to generate a synchronization control signal, wherein when the low-side switch drive signal is higher than the preset threshold, the synchronization control signal has a first logic level, and when the low-side switch drive signal is lower than the preset threshold, the synchronization signal has a second logic level.

14. The power converter according to claim 12, wherein the synchronous control module comprises: A Zener diode has a cathode coupled to the first terminal through a resistance element and an anode coupled to the second terminal, and the cathode is configured to provide the synchronization control signal. 15 . The power converter of claim 1 , wherein the first terminal of the high-side switch control circuit receives the low-side switch driving signal through a unidirectional conducting device.

16. The power converter of claim 15, wherein the unidirectional conducting device has a reverse breakdown voltage higher than a predetermined voltage value.

17. A switch control circuit for driving a high-side switch in a power converter, comprising a high-side switch and a low-side switch connected in series, the switch control circuit comprising: A first terminal, for receiving a low-side switch driving signal; A second terminal configured as a reference ground terminal of the switch control circuit; and A third terminal is configured as an output terminal of the switch control circuit, for providing a high-side switch driving signal; The switch control circuit is configured to derive power from a low-side switch drive signal received at the first terminal.

18. The switch control circuit as described in claim 17 is configured to keep the high-side switch drive signal in a reset logic state with reference to the potential at the second terminal of the high-side switch control circuit when the low-side switch drive signal is higher than a preset threshold, and to allow the high-side switch drive signal to switch between a reset logic state and a set logic state with reference to the potential at the second terminal of the high-side switch control circuit when the low-side switch drive signal is lower than a preset threshold.

19. The switch control circuit as claimed in claim 17, wherein the switch control circuit is integrated on a semiconductor die or packaged in an integrated circuit chip.

20. The switch control circuit of claim 17, further comprising: A fourth terminal is configured to provide a regulated voltage signal when the capacitive energy storage device is coupled between the fourth terminal and the second terminal of the switch control circuit.

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