Half-bridge LLC resonant circuit, power panel and display device

Abstract

The utility model discloses a half-bridge LLC resonant circuit, a power panel and a display device. The half-bridge LLC resonant circuit comprises a half-bridge LLC topology module, a first capacitor, a second capacitor and a multiplexing resistor unit. The first capacitor and the second capacitor are connected in series to form an energy storage string, one end of the energy storage string is connected with the first end of the first switch unit, and the other end is connected with the second end of the second switch unit; one end of the multiplexing resistor unit is connected with a first series node, the other end is connected with a second series node, the first series node is a connection node of the first capacitor and the second capacitor, and the second series node is a connection node of the first switch unit and the second switch unit. The first capacitor and the second capacitor are connected in series and then are connected in parallel with the first switch unit and the second switch unit which are connected in series, a feedback path of high-frequency noise generated by the half-bridge LLC topology module at the switch node and high-frequency parasitic oscillation in the circuit is formed, the noise can quickly return to the source, and it is ensured that the noise path is controllable.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a half-bridge LLC resonant circuit, a power supply board, and a display device. Background Art

[0002] With the improvement of people's living standards and the popularization of smart home appliances, the demand for high-power and high-efficiency power supplies for display products such as televisions and monitors is becoming increasingly apparent. The flyback power supply topology can no longer meet the power supply requirements. Therefore, the use of an LLC resonant circuit consisting of two inductors and one capacitor as the main power topology to improve power supply efficiency has become the mainstream choice. Among them, the half-bridge LLC topology is a high-frequency, high-efficiency, and cost-effective conversion topology commonly used in power converters. It generates an excitation source in two switching devices and inputs it into the resonant cavity to form a resonant circuit, achieving zero voltage switching (ZVS) and zero current switching (ZCS), thereby greatly improving conversion efficiency.

[0003] The current half-bridge LLC topology causes high-frequency oscillations due to transformer leakage inductance, parasitic capacitance of semiconductor devices, and parasitic inductance and capacitance of printed circuit board (PCB) traces. The high-frequency oscillations in the square wave contain abundant high-order harmonics, which can cause electromagnetic interference (EMI) radiation to fail to meet design requirements in some frequency bands.

[0004] In the related art, high-frequency oscillations are weakened by connecting corresponding RC absorption circuits in parallel to the two switching tubes in the half-bridge LLC topology. However, the RC absorption circuits in the related art cannot make the high-frequency noise generated by the half-bridge LLC topology at the switching node and the high-frequency parasitic oscillations in the circuit return to the noise source via the shortest path, resulting in an uncontrollable noise path. Utility Model Content

[0005] In view of the above problems, the present application provides a half-bridge LLC resonant circuit, a power supply board and a display device to solve the above technical problems.

[0006] In a first aspect, the present application provides a half-bridge LLC resonant circuit, the half-bridge LLC resonant circuit comprising a half-bridge LLC topology module, a first capacitor, a second capacitor, and a multiplexed resistance unit, the half-bridge LLC topology module comprising a first switch unit and a second switch unit connected in series;

[0007] The first capacitor and the second capacitor are connected in series to form an energy storage string, one end of the energy storage string is connected to the first end of the first switch unit, and the other end is connected to the second end of the second switch unit;

[0008] One end of the multiplexed resistance unit is connected to a first series node, and the other end is connected to a second series node, wherein the first series node is a connection node between the first capacitor and the second capacitor, and the second series node is a connection node between the first switch unit and the second switch unit.

[0009] In a possible implementation of the present application, the first switching unit includes a first transistor, the first end of the first transistor is connected to the voltage signal and the first end of the first capacitor, the second end of the first transistor is connected to the second end of the first capacitor through a multiplexed resistance unit, and the control end of the first transistor is connected to the half-bridge control unit.

[0010] In a possible implementation of the present application, the second switching unit includes a second transistor, the first end of the second transistor is connected to the first end of the second capacitor through a multiplexed resistance unit, the second end of the second transistor is connected to the second end of the second capacitor and the ground end, and the control end of the second transistor is connected to the half-bridge control unit.

[0011] In a possible implementation of the present application, the multiplexed resistor unit includes a first resistor and a second resistor in parallel, a first parallel node of the first resistor and the second resistor is connected to a first series node, and a second parallel node of the first resistor and the second resistor is connected to a second series node.

[0012] In a possible implementation of the present application, the multiplexed resistance unit includes a first chip ferrite bead and a second chip ferrite bead in parallel, the third parallel node of the first chip ferrite bead and the second chip ferrite bead is connected to the first series node, and the fourth parallel node of the first chip ferrite bead and the second chip ferrite bead is connected to the second series node.

[0013] In a possible implementation of the present application, the multiplexed resistor unit includes an inserted magnetic bead, one end of the inserted magnetic bead is connected to the first series node, and the other end is connected to the second series node.

[0014] In a possible implementation of the present application, the half-bridge LLC topology module also includes a resonant inductor, a transformer and a resonant capacitor, one end of the resonant inductor is connected to the second series node, and the other end is connected to the first end of the primary winding of the transformer, the second end of the primary winding of the transformer is connected to the first end of the resonant capacitor, and the second end of the resonant capacitor is connected to the ground end.

[0015] In a possible implementation of the present application, the half-bridge LLC resonant circuit further includes a grounded electrolytic capacitor, and the positive electrode of the electrolytic capacitor is connected to the power input terminal of the half-bridge LLC topology module.

[0016] In a second aspect, the present application further provides a power supply board, which includes a board body and a half-bridge LLC resonant circuit as described in the first aspect and arranged on the board body.

[0017] In a third aspect, the present application further provides a display device, which includes a device body and a half-bridge LLC resonant circuit such as the first aspect or the power supply board of the second aspect, which is arranged on the device body.

[0018] From the above content, it can be concluded that this application has the following beneficial effects:

[0019] In the present application, by connecting the multiplexed resistance unit between the first series node and the second series node, the first capacitor and the multiplexed resistance unit constitute the absorption module of the first switch unit, and the second capacitor and the multiplexed resistance unit constitute the absorption module of the second switch unit, thereby weakening the high-frequency oscillation of the half-bridge LLC topology module and reducing EMI radiation; at the same time, the first capacitor and the second capacitor are connected in series and then in parallel at both ends of the first switch unit and the second switch unit, forming a feedback path for the high-frequency noise generated by the half-bridge LLC topology module at the switch node and the high-frequency parasitic oscillation in the circuit, so that the noise can quickly return to the source, reducing the high-frequency loop, ensuring that the noise path is controllable, further improving EMI, and improving circuit reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of a half-bridge LLC topology in the related art;

[0022] Figure 2 yes Figure 1 A waveform diagram of a square wave generated between node a and node b is shown;

[0023] Figure 3 yes Figure 2 A time domain expansion diagram of the rising edge circled in the middle;

[0024] Figure 4 This is a schematic diagram of a half-bridge LLC topology with an added snubber circuit in the related art;

[0025] Figure 5 yes Figure 4 A waveform diagram of the voltage between node a and node b is shown;

[0026] Figure 6 yes Figure 4 A schematic diagram of the high-frequency noise loop in the half-bridge LLC topology is shown;

[0027] Figure 7 1 is a structural diagram of a half-bridge LLC resonant circuit provided in an embodiment of the present application;

[0028] Figure 8 is another structural diagram of a half-bridge LLC resonant circuit provided in an embodiment of the present application;

[0029] Figure 9 1 is a schematic diagram of a circuit principle of a half-bridge LLC resonant circuit provided in an embodiment of the present application;

[0030] Figure 10 This is another circuit principle diagram of the half-bridge LLC resonant circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0032] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described 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, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0033] In the embodiments of the present application, it should be noted that, in this document, relational terms such as first and second, etc., are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0034] Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not explicitly listed or inherent to such article or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the article or device comprising the element.

[0035] In the description of the embodiments of this application, words such as "example" or "for example" are used to indicate an example, illustration, or description. Any embodiment or design described as "for example" or "for example" in the embodiments of this application is not to be construed as being preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to clearly present relative concepts.

[0036] In addition, in the embodiments of the present application, "plurality" refers to two or more. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two, or more. For example, "including at least one" means including one, two, or more, and does not limit which ones are included. For example, "including at least one of A, B, and C" means including A, B, C, A and B, A and C, B and C, or A, B, and C.

[0037] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0038] The first electrode / first end of each transistor used in the embodiments of the present application is one of the source and the drain, and the second electrode / second end of each transistor is the other of the source and the drain. Since the source and drain of the transistor can be symmetrical in structure, the source and drain can be structurally indistinguishable, that is, the first electrode / first end and the second electrode / second end of the transistor in the embodiments of the present application can be structurally indistinguishable. For example, in the case where the transistor is a P-type transistor, the first electrode / first end of the transistor is the source, and the second electrode / second end is the drain; for example, in the case where the transistor is an N-type transistor, the first electrode / first end of the transistor is the drain, and the second electrode / second end is the source.

[0039] In the circuit structure provided in the embodiments of the present application, the first node, the second node and other nodes do not represent actual components, but represent the junction points of related couplings in the circuit diagram. That is, these nodes are nodes formed by the equivalent junction points of related couplings in the circuit diagram.

[0040] Before introducing the half-bridge LLC resonant circuit, power supply board and display device of the present application, the relevant background information of the embodiments of the present application is first introduced.

[0041] like Figure 1 As shown, Figure 1This is a schematic diagram of the principle of the half-bridge LLC topology in the related art. In the figure, two metal-oxide-semiconductor field-effect transistors (MOSFETs), namely MOS tube Q1' and MOS tube Q2', are alternately turned on, generating a current between node a and node b. Figure 2 The square wave with a duty cycle of 50% is used as the input excitation of the LLC resonant cavity (the first resonant inductor Lr', the primary side of the first transformer T' and the first resonant capacitor Cr'), causing the resonant cavity to resonate and transfer energy to the secondary side of the first transformer T'. Figure 2 The rising edge circled in the middle is expanded in the time domain to obtain Figure 3 The time domain expansion diagram shown is based on Figure 3 It can be seen that high-frequency oscillations occur on the rising edge of the waveform, caused by transformer leakage inductance, parasitic capacitance of semiconductor devices, and parasitic inductance and capacitance of PCB traces. The high-frequency oscillations in square waves contain abundant high-order harmonics, which can cause EMI radiation in some frequency bands to fail to meet power supply design requirements.

[0042] To solve this problem, Figure 4 As shown, in the related art, the characteristic that the voltage across the capacitor cannot change suddenly is used to weaken the high-frequency oscillation by adding an absorption circuit, thereby reducing the high-order harmonic components and lowering the amplitude of the harmonic components, and ultimately achieving the purpose of optimizing EMI radiation. Figure 4 The absorption circuit shown in FIG is a Q1' resistor-capacitor absorption circuit connected in parallel at both ends of the MOS transistor Q1' and a Q2' resistor-capacitor absorption circuit connected in parallel at both ends of the MOS transistor Q2'. Figure 5 As shown in Figure 2, after adding the absorption circuit, the rising edge of the voltage waveform between node a and node b is smoother than that of Figure 3 No high frequency oscillation.

[0043] However, since the equivalent series resistance (ESR) of the first electrolytic capacitor E1' is larger than the ESR of the first ceramic capacitor C1' and the second ceramic capacitor C2', Figure 6 As shown by the middle dashed line, only a portion of the high-frequency noise generated by the power switch node of the half-bridge LLC topology and the high-frequency parasitic oscillation in the circuit will return to the noise source through the first electrolytic capacitor E1'. The remaining noise cannot return to the noise source via the shortest path, resulting in an uncontrollable noise path.

[0044] Based on this, an embodiment of the present application provides a half-bridge LLC resonant circuit, a power supply board and a display device. The half-bridge LLC resonant circuit weakens the high-frequency oscillation of the half-bridge LLC topology module by reusing a resistance unit, a first capacitor and a second capacitor to form an absorption module. At the same time, by connecting the first capacitor and the second capacitor in series and then in parallel with the half-bridge LLC topology module, a feedback path for the high-frequency noise generated by the half-bridge LLC topology module at the switching node and the high-frequency parasitic oscillation in the circuit is formed, so that the noise can quickly return to the source, ensuring that the noise path is controllable.

[0045] The half-bridge LLC resonant circuit, power supply board and display device provided in this application are respectively introduced in detail below.

[0046] First, an embodiment of the present application provides a half-bridge LLC resonant circuit, which can be used in a display device or integrated in a display device. The display device can be a display electronic device such as a television, a monitor, or a large display screen.

[0047] See also Figure 7 , Figure 7 1 is a structural diagram of a half-bridge LLC resonant circuit provided in an embodiment of the present application. The half-bridge LLC resonant circuit 100 may include a first capacitor C1, a second capacitor C2, a multiplexed resistor unit 110 and a half-bridge LLC topology module 120, wherein the half-bridge LLC topology module 120 includes a first switch unit 1201 and a second switch unit 1202 connected in series; the first capacitor C1 and the second capacitor C2 are connected in series to form an energy storage string, one end of the energy storage string is connected to the first end of the first switch unit 1201, and the other end is connected to the second end of the second switch unit 1202; one end of the multiplexed resistor unit 110 is connected to a first series node A, and the other end is connected to a second series node B, wherein the first series node A is a connection node of the first capacitor C1 and the second capacitor C2, and the second series node B is a connection node of the first switch unit 1201 and the second switch unit 1202.

[0048] In the embodiment of the present application, the power input terminal of the half-bridge LLC topology module 120 can be connected to a voltage source to receive the voltage signal VIN. It is understandable that the voltage signal VIN can be a DC voltage signal obtained by rectifying the AC voltage signal.

[0049] Due to the "DC-blocking and AC-passing" characteristic of the capacitor, both the first capacitor C1 and the second capacitor C2 can pass high-frequency signals. Therefore, the energy storage string formed by connecting the first capacitor C1 and the second capacitor C2 in series in parallel with the first switch unit 1201 and the second switch unit 1202 connected in series can cooperate with the resonant cavity of the first switch unit 1201 and the half-bridge LLC topology module 120 to provide a feedback path for high-frequency noise. That is, the first capacitor C1, the second capacitor C2, the first switch unit 1201 and the resonant cavity of the half-bridge LLC topology module 120 can form a high-frequency noise feedback loop, as shown by the red dotted line, so that the high-frequency noise quickly returns to the source.

[0050] The multiplexed resistance unit 110 is connected between a first series node A and a second series node B, and the first series node A is a connection node between the first capacitor C1 and the second capacitor C2, and the second series node B is a connection node between the first switch unit 1201 and the second switch unit 1202. The multiplexed resistance unit 110 cooperates with the first capacitor C1 to form a first absorption loop for the first switch unit 1201, as shown by the blue dotted line, and the multiplexed resistance unit 110 cooperates with the second capacitor C2 to form a second absorption loop for the second switch unit 1202, as shown by the green dotted line.

[0051] In practical applications, if a RC absorption circuit has only one resistor in series with a capacitor, the power consumption may be too high, resulting in severe heat generation and the temperature rise may not meet the requirements. Figure 4 It can be seen that in the related art, adding one RC absorption circuit to the half-bridge LLC topology requires the use of at least one capacitor and two resistors. Therefore, two RC absorption circuits require a total of at least two capacitors and four resistors. For example, when using plug-in capacitors, if the pin spacing meets the creepage distance requirements, one RC absorption circuit can meet the design requirements with one capacitor; when using chip capacitors, two chip capacitors are required to be used in series to meet the creepage distance requirements. In this way, the increase in electronic components not only complicates the circuit structure and increases the cost, but also requires occupying PCB area and expanding the PCB, resulting in a decrease in PCB power density.

[0052] In this embodiment, the first and second absorption loops weaken high-frequency oscillations in the circuit, thereby reducing high-order harmonic components and lowering their amplitudes, thereby optimizing EMI radiation. Furthermore, the first and second absorption loops share a common resistor unit 110, reducing the number of electronic components, thereby streamlining the circuit, lowering costs, reducing PCB footprint, and increasing power density.

[0053] In an embodiment of the present application, by connecting the multiplexed resistance unit 110 between the first series node A and the second series node B, the first capacitor C1 and the multiplexed resistance unit 110 constitute an absorption module of the first switch unit 1201, and the second capacitor C2 and the multiplexed resistance unit 110 constitute an absorption module of the second switch unit 1202, thereby weakening the high-frequency oscillation of the half-bridge LLC topology module 120 and reducing EMI radiation; at the same time, the first capacitor C1 and the second capacitor C2 are connected in series and then in parallel at both ends of the first switch unit 1201 and the second switch unit 1202, forming a feedback path for the high-frequency noise generated by the half-bridge LLC topology module 120 at the switch node and the high-frequency parasitic oscillation in the circuit, so that the noise can quickly return to the source, reducing the high-frequency loop, ensuring that the noise path is controllable, further improving EMI, and improving circuit reliability.

[0054] Next, continue to Figure 7 Each unit module shown and the specific implementation methods that may be used in practical applications are described in detail.

[0055] See also Figure 8 In some embodiments of the present application, the first switching unit 1201 includes a first transistor Q1, the first end of the first transistor Q1 is connected to the voltage signal VIN and the first end of the first capacitor C1, the second end of the first transistor Q1 is connected to the second end of the first capacitor C1 through the multiplexed resistance unit 110, and the control end of the first transistor Q1 is connected to the half-bridge control unit 130.

[0056] In an embodiment of the present application, the half-bridge control unit 130 can output a pulse width modulation (PWM) signal to control the first transistor Q1 to be turned on or off. The half-bridge control unit 130 can be a microcontroller unit (MCU), a central processing unit (CPU), etc.

[0057] The first transistor Q1 can be any existing controllable switch tube, including but not limited to a P-type MOS tube, an N-type MOS tube, an insulated gate bipolar transistor (IGBT), etc. The specific selection can be made according to the actual application scenario and is not limited here.

[0058] Please continue reading Figure 8In some embodiments of the present application, the second switching unit 1202 may include a second transistor Q2, the first end of the second transistor Q2 is connected to the first end of the second capacitor C2 through the multiplexed resistance unit 110, the second end of the second transistor Q2 is connected to the second end of the second capacitor C2 and the ground terminal SGND, and the control end of the second transistor Q2 is connected to the half-bridge control unit 130.

[0059] In the embodiment of the present application, the half-bridge control unit 130 can also output a PWM signal to control the second transistor Q2 to be turned on or off, and the first transistor Q1 and the second transistor Q2 are alternately turned on and off in response to the PWM signal from the half-bridge control unit 130 to supply energy to the secondary side of the transformer T in the resonant cavity, thereby achieving ZVS and ZCS and improving the operating efficiency of the circuit.

[0060] The second transistor Q2 can also adopt any existing controllable switch tube, including but not limited to P-type MOS tube, N-type MOS tube, insulated gate bipolar transistor (IGBT), etc. The specific selection can be made according to the actual application scenario and is not limited here.

[0061] It should be noted that the control of the first transistor Q1 and the second transistor Q2 by the half-bridge control unit 130 can be achieved through existing technologies, and this application does not involve improvements to the control method.

[0062] It is understandable that the first capacitor C1 and the second capacitor C2 in the embodiment of the present application can be plug-in capacitors or chip capacitors. When plug-in capacitors are used, if the pin spacing meets the creepage distance requirements, then the first capacitor C1 and the second capacitor C2 can each use a single plug-in capacitor to meet the design requirements; when chip capacitors are used, then the first capacitor C1 and the second capacitor C2 each need to use two chip capacitors in series to meet the creepage distance requirements.

[0063] like Figure 9 As shown, in some embodiments of the present application, the multiplexed resistance unit 110 may include a first resistor R1 and a second resistor R2 in parallel, wherein a first parallel node of the first resistor R1 and the second resistor R2 is connected to a first series node A, and a second parallel node of the first resistor R1 and the second resistor R2 is connected to a second series node B.

[0064] In the embodiment of the present application, the first resistor R1 and the second resistor R2 connected in parallel and the first capacitor C1 constitute an absorption circuit for the first transistor Q1, and the first resistor R1 and the second resistor R2 connected in parallel and the second capacitor C2 constitute an absorption circuit for the second transistor Q2, thereby weakening the high-frequency oscillation in the circuit, reducing the high-order harmonic components and the amplitude of the harmonic components, and optimizing EMI radiation. At the same time, Figure 9The high-frequency noise feedback loop shown by the red dotted line in the figure provides a feedback path for the high-frequency noise in the circuit, ensuring that the noise quickly returns to the source, further optimizing EMI.

[0065] Moreover, taking the plug-in capacitor that meets the creepage distance requirement as an example, compared with Figure 4 For example, if two plug-in capacitors and four resistors are added, the two RC absorption circuits in the embodiment of the present application share the resistor, and the same effect can be achieved by using only two plug-in capacitors and two resistors, without affecting the circuit performance, saving PCB area, and also reducing the PCB expansion area.

[0066] As an example, the first resistor R1 and the second resistor R2 may be 1206 resistors with a resistance of 20 ohm, and the first capacitor C1 and the second capacitor C2 may be capacitors with a capacitance of 100 PF.

[0067] In some embodiments of the present application, the multiplexed resistor unit 110 may also include a first chip ferrite bead and a second chip ferrite bead connected in parallel. The connection relationship between the first chip ferrite bead and the second chip ferrite bead and other components is the same as that of the first resistor R1 and the second resistor R2, and will not be repeated here.

[0068] In the embodiment of the present application, the first chip ferrite bead and the second chip ferrite bead can better suppress high-frequency noise and spike interference on the signal line and the power line compared to resistors, thereby improving the reliability of the circuit.

[0069] like Figure 10 As shown, in some embodiments of the present application, the multiplexed resistor unit 110 may include an inserted magnetic bead BL1 , one end of the inserted magnetic bead BL1 is connected to the first series node A, and the other end is connected to the second series node B.

[0070] The plug-in magnetic bead BL1 can also be connected between the first capacitor C1 and the second capacitor C2 at one end, and between the first transistor Q1 and the second transistor Q2 at the other end. Figure 10 The blue dotted line shown in FIG is the absorption loop for the first transistor Q1 , and the green solid line is the absorption loop for the second transistor Q2 .

[0071] Since the plug-in magnetic beads have excellent heat dissipation performance, in the embodiment of the present application, by using one plug-in magnetic bead in combination with the first capacitor C1 and the second capacitor C2, the function of the absorption circuit can also be achieved, further reducing the number of electronic components, improving product power density, and enhancing competitiveness.

[0072] Please continue reading Figure 9 and Figure 10In some embodiments of the present application, the half-bridge LLC topology module 120 may further include a resonant inductor Lr, a transformer T and a resonant capacitor Cr. The resonant inductor Lr, the transformer T and the resonant capacitor Cr constitute a resonant cavity. One end of the resonant inductor Lr is connected to the second series node B, and the other end is connected to the first end of the primary winding of the transformer T. The second end of the primary winding of the transformer T is connected to the first end of the resonant capacitor Cr, and the second end of the resonant capacitor Cr is connected to the ground terminal SGND.

[0073] It can be understood that the half-bridge LLC topology module 120 can also include a first rectifier diode D1, a second rectifier diode D2 and an output capacitor E2 connected to the secondary winding of the transformer T. The working principle of the half-bridge LLC topology module 120 is the same as the working principle of the existing half-bridge LLC topology, which will not be repeated here.

[0074] In other examples, the first rectifier diode D1 and the second rectifier diode D2 of the half-bridge LLC topology module 120 may also be replaced by MOS transistors to further improve product operating efficiency by using synchronous rectification.

[0075] In some embodiments of the present application, the half-bridge LLC resonant circuit 100 may further include a grounded electrolytic capacitor E1 , wherein a positive electrode of the electrolytic capacitor E1 is connected to a power input terminal of the half-bridge LLC topology module 120 .

[0076] In the embodiment of the present application, by connecting the electrolytic capacitor E1 to the power input terminal, the electrolytic capacitor E1 can store and release electrical energy to balance the current fluctuation and ensure the stability of the voltage signal VIN.

[0077] Based on the half-bridge LLC resonant circuit in the above embodiment, on the basis of the above embodiment, the embodiment of the present application further provides a power supply board, which may include a board body and a circuit board provided on the board body. Figures 7 to 10 Corresponding to the half-bridge LLC resonant circuit in any embodiment.

[0078] The board body can be a printed circuit board (PCB) of a power supply, and the half-bridge LLC resonant circuit is integrated on the PCB. Alternatively, the board body can also be a circuit board integrated with a half-bridge LLC resonant circuit, and the circuit board is connected to a power supply PCB.

[0079] Since the power board includes the present application Figures 7 to 10 Corresponding to the half-bridge LLC resonant circuit in any embodiment, therefore, the present application can be implemented as follows Figures 7 to 10 For all the beneficial effects that can be achieved by the half-bridge LLC resonant circuit in any embodiment, please refer to the previous description in detail and will not be repeated here.

[0080] On the basis of the above embodiments, the embodiment of the present application further provides a display device, which may include a device body and a display device provided on the device body. Figures 7 to 10 Corresponding to the half-bridge LLC resonant circuit or power board in any embodiment.

[0081] The display device can be a display electronic device such as a television, a monitor, or a large display screen.

[0082] Since the display device includes the present application Figures 7 to 10 Corresponding to the half-bridge LLC resonant circuit in any embodiment, therefore, the present application can be implemented as follows Figures 7 to 10 For all the beneficial effects that can be achieved by the half-bridge LLC resonant circuit in any embodiment, please refer to the previous description in detail and will not be repeated here.

[0083] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A half-bridge LLC resonant circuit, characterized in that: It includes a half-bridge LLC topology module, a first capacitor, a second capacitor and a multiplexed resistance unit, wherein the half-bridge LLC topology module includes a first switch unit and a second switch unit connected in series; The first capacitor and the second capacitor are connected in series to form an energy storage string, one end of the energy storage string is connected to the first end of the first switch unit, and the other end is connected to the second end of the second switch unit; One end of the multiplexed resistance unit is connected to a first series node, and the other end is connected to a second series node, wherein the first series node is a connection node between the first capacitor and the second capacitor, and the second series node is a connection node between the first switch unit and the second switch unit.

2. The half-bridge LLC resonant circuit according to claim 1, characterized in that: The first switching unit includes a first transistor, the first end of the first transistor is connected to the voltage signal and the first end of the first capacitor, the second end of the first transistor is connected to the second end of the first capacitor through the multiplexed resistance unit, and the control end of the first transistor is connected to the half-bridge control unit.

3. The half-bridge LLC resonant circuit according to claim 1, characterized in that: The second switching unit includes a second transistor, the first end of the second transistor is connected to the first end of the second capacitor through the multiplexed resistance unit, the second end of the second transistor is connected to the second end of the second capacitor and the ground end, and the control end of the second transistor is connected to the half-bridge control unit.

4. The half-bridge LLC resonant circuit according to any one of claims 1 to 3, characterized in that: The multiplexed resistor unit includes a first resistor and a second resistor connected in parallel, a first parallel node of the first resistor and the second resistor is connected to the first series node, and a second parallel node of the first resistor and the second resistor is connected to the second series node.

5. The half-bridge LLC resonant circuit according to any one of claims 1 to 3, characterized in that: The multiplexed resistor unit includes a first chip magnetic bead and a second chip magnetic bead connected in parallel, a third parallel node of the first chip magnetic bead and the second chip magnetic bead is connected to the first series node, and a fourth parallel node of the first chip magnetic bead and the second chip magnetic bead is connected to the second series node.

6. The half-bridge LLC resonant circuit according to any one of claims 1 to 3, characterized in that: The multiplexed resistor unit includes an inserted magnetic bead, one end of which is connected to the first series node, and the other end of which is connected to the second series node.

7. The half-bridge LLC resonant circuit according to claim 1, characterized in that: The half-bridge LLC topology module also includes a resonant inductor, a transformer and a resonant capacitor, one end of the resonant inductor is connected to the second series node, and the other end is connected to the first end of the primary winding of the transformer, the second end of the primary winding of the transformer is connected to the first end of the resonant capacitor, and the second end of the resonant capacitor is connected to the ground end.

8. The half-bridge LLC resonant circuit according to claim 1, characterized in that: The half-bridge LLC resonant circuit further includes a grounded electrolytic capacitor, wherein a positive electrode of the electrolytic capacitor is connected to a power input terminal of the half-bridge LLC topology module.

9. A power board, characterized in that: The invention comprises a card body and a half-bridge LLC resonant circuit according to any one of claims 1 to 8, which is arranged on the card body.

10. A display device, characterized in that: The device comprises a device body and a half-bridge LLC resonant circuit according to any one of claims 1 to 8 or a power supply board according to claim 9, which is arranged on the device body.

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