A multiphase independent synchronous rectification device and power supply equipment

Abstract

The utility model discloses a kind of multi-phase independent synchronous rectification device and power supply equipment, it is related to switching power supply technical field.Specifically including power transformer and at least two synchronous rectification modules, power transformer at least includes two secondary output windings;Each synchronous rectification module includes synchronous rectification controller and power transistor, the main electrode end of power transistor is electrically connected at the two ends of secondary output winding, the driving end of power transistor is electrically connected with synchronous rectification controller;The output end of each synchronous rectification module is connected in parallel, and is used to supply power for load uniformly, the output end of each synchronous rectification module is formed after rectification by its internal power transistor;The synchronous rectification controller of each synchronous rectification module is electrically isolated each other.Not only reduce the requirement to single synchronous rectification controller performance, make each controller only need to process partial original total current, effectively solve the problem that high-performance controller is expensive in prior art, and conduction loss is big.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, and in particular to a multiphase independent synchronous rectifier and power supply equipment. Background Technology

[0002] In applications such as servers, communication equipment, and high-performance computing, the requirements for the power density, output current capability, and conversion efficiency of core switching power supplies are increasing.

[0003] In existing technologies, to achieve high current output, the commonly used technical solution in the industry is to connect multiple windings of the power transformer secondary side in parallel on the AC side, or to use a single winding with multiple strands wound in parallel, concentrating energy into a single channel, which is then processed by a high-power synchronous rectifier (SR) circuit. However, this centralized current architecture has the following shortcomings: Because the total current that needs to be detected and controlled is huge and its dynamic changes are drastic, strong electromagnetic noise interference will be generated. This requires the SR controller to have extremely high response speed, noise immunity and detection accuracy, which makes the technical threshold of such controllers high and the price very expensive. Therefore, the requirements for synchronous rectifier controllers are extremely demanding.

[0004] According to the formula P=I 2 As R indicates, conduction losses are proportional to the square of the current, and the concentration of total current in a single path will lead to huge energy losses. At the same time, the total parasitic capacitance of multiple MOSFETs connected in parallel to carry large currents also increases the switching losses significantly. These factors together lead to a decrease in power conversion efficiency and heat concentration, which seriously affects the reliability and lifespan of the product. Therefore, the energy loss and heat during conduction are highly concentrated.

[0005] Therefore, this application aims to solve the technical problems of complex and expensive control and high energy loss caused by centralized processing of total current in the prior art. Utility Model Content

[0006] The main purpose of this invention is to provide a multiphase independent synchronous rectifier and power supply device, which aims to replace the expensive and complex controller and reduce conduction losses under high current.

[0007] To achieve the above objectives, this utility model proposes a multiphase independent synchronous rectification device, comprising: A power transformer, wherein the power transformer includes at least two secondary output windings; At least two synchronous rectification modules, the number of which corresponds to the number of secondary output windings, and the input terminal of each synchronous rectification module is electrically connected to the corresponding secondary output winding; each synchronous rectification module includes: Synchronous rectifier controller; A power transistor, wherein the main terminal of the power transistor is electrically connected to both ends of the secondary output winding, and the driving terminal of the power transistor is electrically connected to the synchronous rectifier controller; The output terminals of each synchronous rectification module are connected in parallel and used to supply power to the load uniformly. The output terminal of each synchronous rectification module is formed by the rectification of the power transistor inside it. The synchronous rectification controllers of each synchronous rectification module are electrically isolated from each other.

[0008] Furthermore, the number of synchronous rectification modules is three or more.

[0009] Furthermore, the power transistor is a metal-oxide-semiconductor field-effect transistor with a positive temperature coefficient of on-resistance.

[0010] Furthermore, the synchronous rectification controller and the power transistor are integrated into the same chip package.

[0011] Furthermore, it also includes parallel output buses; One end of the parallel output bus is electrically connected to the output of the multiple synchronous rectification modules, and the other end of the parallel output bus is used to supply power to the load.

[0012] Furthermore, the input terminal of the synchronous rectifier controller of each synchronous rectifier module is electrically connected to the corresponding secondary output winding.

[0013] Furthermore, the synchronous rectification controller includes a detection unit and a drive unit; The input terminal of the detection unit is electrically connected to the main terminal of the power transistor; The input terminal of the driving unit is electrically connected to the detection unit, and the output terminal of the driving unit is electrically connected to the control terminal of the power transistor. The detection unit is used to receive the voltage of the power transistor.

[0014] Furthermore, the detection unit includes a voltage comparator and a logic controller, the voltage comparator being electrically connected to the logic controller, and the logic controller being electrically connected to the drive unit; The input terminal of the voltage comparator is connected to the main terminal of the power transistor, and is used to compare the collected voltage of the power transistor with a preset threshold voltage, and output a level signal to the logic controller. The logic controller is used to receive the level signal and output a digital signal to the drive unit according to the level signal; The driving unit is used to receive the digital signal and drive the control terminal of the power transistor according to the digital signal.

[0015] This application also discloses a power supply device, including a main circuit and a multiphase independent synchronous rectifier as described above, wherein the output terminal of the main circuit is electrically connected to the input terminal of the power transformer of the multiphase independent synchronous rectifier.

[0016] Furthermore, the power supply device is a server power supply, a communication equipment power supply, or a computing equipment power supply.

[0017] The above technical solution has the following advantages: This application reduces the performance requirements of a single synchronous rectifier controller by distributing the total current to multiple isolated synchronous rectifier modules for independent processing. This allows each controller to handle only a portion of the original total current, enabling the use of lower-cost and more mature standard controllers to build a power supply system capable of outputting a large total current. It also reduces the overall circuit conduction loss, effectively solving the problem of high cost and high conduction loss of high-performance controllers in the prior art.

[0018] This application utilizes a metal-oxide-semiconductor field-effect transistor with a positive temperature coefficient of conduction resistance to achieve automatic current balancing between parallel paths. This eliminates the need for additional complex active current sharing circuits, simplifying system design, reducing costs, and improving reliability. Furthermore, since losses are evenly distributed across multiple modules, the formation of local hot spots is avoided, simplifying heat dissipation design.

[0019] This invention utilizes the natural slight differences in the operating timing of each independent synchronous rectifier controller to create an interleaved parallel operation effect, which helps reduce the total switching losses and output voltage ripple of the system. In addition, if one synchronous rectifier module fails, the remaining synchronous rectifier modules can still continue to work without causing the entire system to collapse immediately, thus enhancing the robustness and availability of the system. Attached Figure Description

[0020] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 A schematic diagram of a centralized synchronous rectification architecture in existing technology; Figure 2 This is a schematic diagram of an embodiment of the present utility model; Figure 3 This is a block diagram of the internal structure of a single synchronous rectification module of this utility model; Figure 4 This is a block diagram of the internal structure of the detection unit of this utility model.

[0021] In the diagram: 1. Power transformer; 2. Synchronous rectification module; 21. Synchronous rectification controller; 22. Power transistor; 221. Power supply unit; 222. Detection unit; 2221. Voltage comparator; 2222. Logic controller; 2223. Delay unit; 223. Drive unit; 3. Load. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain this utility model and do not constitute a limitation on this utility model.

[0023] like Figure 1 As shown in the attached figure, this is a schematic diagram of the prior art, which uses a single synchronous rectifier controller to regulate multiple power switching devices. It must have extremely high response speed, noise immunity and detection accuracy, which makes the technical threshold of such controllers high and the price very expensive. Therefore, the requirements for synchronous rectifier controllers are extremely demanding.

[0024] like Figure 2 and Figure 3 As shown, a multiphase independent synchronous rectification device includes a power transformer 1 and at least two synchronous rectification modules 2. The power transformer 1 includes at least two secondary output windings. The number of synchronous rectification modules 2 corresponds to the number of secondary output windings. The input terminal of each synchronous rectification module 2 is electrically connected to the corresponding secondary output winding. Each synchronous rectification module 2 includes a synchronous rectification controller 21 and a power transistor 22. The main terminal of the power transistor 22 is electrically connected to both ends of the secondary output winding, and the driving terminal of the power transistor 22 is electrically connected to the synchronous rectification controller 21. The output terminals of each synchronous rectification module 2 are connected in parallel and used to supply power to the load 3. The output terminal of each synchronous rectification module 2 is formed by rectification by its internal power transistor 22. The synchronous rectification controllers 21 of each synchronous rectification module 2 are electrically isolated from each other.

[0025] Reference Figure 2 This embodiment provides a two-phase independent synchronous rectification device. The device includes a power transformer 1, with two independent secondary output windings on its secondary side. It also includes two synchronous rectification modules 2, the number of which is the same as the number of secondary output windings, and each synchronous rectification module 2 is connected to a corresponding secondary output winding.

[0026] Each synchronous rectification module 2 includes a synchronous rectification controller 21 and a power transistor 22. The power transistor 22 is preferably a MOSFET, with its main terminals being the drain and source, respectively. It is connected to the two ends of the secondary output winding according to the specific rectification topology. The control terminal of the power transistor 22 is the gate of the MOSFET, and the control terminal of the power transistor 22 is electrically connected to the output terminal of the synchronous rectification controller 21.

[0027] The DC current of the two synchronous rectifier modules 2 is connected in parallel to a common output bus, which is connected to the subsequent load 3.

[0028] The key feature of this embodiment is that the synchronous rectifier controllers 21 between the multiple synchronous rectifier modules 2 are electrically isolated from each other, and there are no electrical connection lines of any kind between the synchronous rectifier controllers 21 for synchronization, communication or current sharing control. They are two completely independent units.

[0029] In one embodiment of this application, the number of synchronous rectification modules 2 is three or more. Therefore, this embodiment provides an N-phase independent synchronous rectification device, where N is an integer greater than 2. The secondary side of the power transformer 1 has N secondary output windings, namely LS1, LS2, ..., LSN. Correspondingly, it also includes N synchronous rectification modules 2, with the number of synchronous rectification modules 2 ranging from 1 to N. Each synchronous rectification module 2 is uniquely connected to a corresponding single secondary winding. For example, the first synchronous rectification module 2 is electrically connected to LS1, the second synchronous rectification module 2 is electrically connected to LS2, and so on, until the Nth synchronous rectification module 2 is electrically connected to LSN.

[0030] Each synchronous rectification module 2 contains an independent synchronous rectification controller 21 and at least one power transistor 22SRMOS. The DC output terminals of N synchronous rectification modules 2 are finally connected in parallel to power the load 3. The N synchronous rectification controllers 21 are electrically isolated from each other and work independently.

[0031] like Figure 2 As shown in this embodiment, in order to ensure the natural current sharing performance among the N channels, the N secondary output windings of the power transformer 1 can be manufactured using a parallel winding process. This ensures that the key electrical parameters such as leakage inductance and DC resistance of each secondary output winding have a high degree of consistency, providing a good physical basis for subsequent passive current sharing.

[0032] Power transistor 22 is a metal-oxide-semiconductor field-effect transistor with a positive temperature coefficient of on-resistance.

[0033] In the above embodiments, the selected power transistors 22 are all MOSFETs with a positive temperature coefficient, which means that the on-resistance of the MOSFET increases as its junction temperature increases. Under the architecture of this embodiment, automatic current balancing between parallel paths can be achieved. Its operation is a dynamic negative feedback adjustment process, as detailed below: If, due to slight differences in component parameters, the output current of the first synchronous rectification module 2 is initially slightly greater than that of the second synchronous rectification module 2, this will cause the drain and source temperatures of the MOSFETs in the first synchronous rectification module 2 to be slightly higher than those in the second synchronous rectification module 2. Due to the positive temperature coefficient of MOSFETs, the on-resistance of the drain and source will increase accordingly. According to Ohm's law, the increased resistance of the path will naturally suppress the current growth in that path. Meanwhile, the second synchronous rectification module 2, due to its smaller current and lower temperature, has a relatively smaller on-resistance MOSFET and will tend to share more current. This negative feedback process is continuous and automatic, eventually bringing the current and temperature of the two synchronous rectification modules 2 to a dynamic equilibrium point. Actual measurements show that this method can reduce the current difference between branches to less than 5% and the temperature difference between MOSFETs to less than 10℃, achieving excellent automatic current sharing without the need for any additional current sharing control circuitry.

[0034] like Figure 2 and Figure 3 As shown, in one embodiment of this application, the synchronous rectifier controller 21 and the power transistor 22 are integrated into the same chip package.

[0035] To achieve higher power density and better switching performance, the synchronous rectifier controller 21 and power transistor 22 in each synchronous rectifier module 2 can be integrated. For example, a synchronous rectifier controller 21 chip and one or more MOSFET chips can be packaged together in a standardized package to form a power integrated module. This can significantly reduce the parasitic inductance of the loop between the output of the synchronous rectifier controller 21 and the gate of the MOSFET, thereby reducing switching losses, improving efficiency, and simplifying PCB layout design.

[0036] like Figure 2 As shown, this application also includes a parallel output bus, one end of which is electrically connected to the output of multiple synchronous rectification modules 2, and the other end of which is used to supply power to the load 3.

[0037] In the above embodiment, the DC output terminals of multiple synchronous rectification modules 2 need to be combined together. This combination point is physically achieved through a parallel output bus. On the PCB board, the parallel output bus can be a large area copper foil layer or multiple layers to carry the total output current. The output terminals of multiple synchronous rectification modules 2 are all connected to the same end of this parallel output bus through a low impedance path. The other end of the parallel output bus supplies power to the final load device 3.

[0038] like Figure 2 and Figure 3 As shown, the synchronous rectification controller 21 of each synchronous rectification module 2 is electrically connected to the corresponding secondary output winding. In the synchronous rectification module 2, in order to accurately determine the switching timing of the drain and source of the power transistor 22, the synchronous rectification controller 21 needs to obtain the voltage information of the secondary output winding to which it is connected. Therefore, the voltage detection pin of the synchronous rectification controller 21 is electrically connected to the two ends of the secondary output winding or its relevant nodes. By monitoring the voltage polarity change of this secondary output winding in real time, the synchronous rectification controller 21 precisely controls the switching on and off of the MOSFET to achieve efficient synchronous rectification.

[0039] The synchronous rectification controller 21 includes a detection unit 222 and a drive unit 223. The input terminal of the detection unit 222 is connected to the main terminal of the power transistor 22. The detection unit 222 is connected to the voltage of the power transistor 22, which is the drain-source voltage Vds. The detection unit 222 changes according to the magnitude and polarity of this Vds voltage. The input terminal of the drive unit 223 is electrically connected to the detection unit 222. The output terminal of the drive unit 223 is electrically connected to the control terminal of the power transistor 22. The detection unit 222 is used to determine when to turn the power transistor 22 on or off, and sends a control signal to the control terminal of the power transistor 22 through the drive unit 223.

[0040] like Figure 3 and Figure 4 As shown, the detection unit 222 includes a voltage comparator 2221 and a logic controller 2222. The voltage comparator 2221 is connected to the logic controller 2222, and the logic controller 2222 is connected to the drive unit 223. The input terminal of the voltage comparator 2221 is connected to the drain voltage and source voltage of the power transistor 22, and is compared with a preset threshold voltage. The compared level signal is then transmitted to the logic controller 2222. The logic controller 2222 receives the level signal, converts it into a digital signal, and transmits it to the drive unit 223. The drive unit 223 receives the digital signal and generates a control signal, which is then transmitted to the control terminal of the power transistor 22.

[0041] The core of the detection unit 222 can be composed of three parts: a voltage comparator 2221, a logic controller 2222, and a drive unit 223. The input terminal of the voltage comparator 2221 is connected to the drain and source of the MOSFET, and is used to compare the real-time Vds voltage with multiple preset threshold voltages inside the chip. For example, the turn-on threshold Vth_on is -5mV and the turn-off threshold Vth_off is +2mV. When Vds is lower than Vth_on, the comparator outputs a high-level signal; when Vds is higher than Vth_off, it outputs a low-level signal.

[0042] The compared level signal is transmitted to the logic controller 2222, a small digital circuit. Upon receiving this level signal, the logic controller 2222 processes it using timing control logic, such as minimum on-time and minimum off-time, to prevent false triggering caused by noise. After processing, the logic controller 2222 outputs a digital signal to the drive unit 223.

[0043] The drive unit 223 is a power amplifier circuit that receives a weak digital signal from the logic controller 2222 and converts it into a control signal with sufficient drive current and voltage swing. This signal is ultimately applied to the gate of the MOSFET to control its reliable turn-on and turn-off.

[0044] In some more specific implementations, to enhance system reliability, each independent synchronous rectification module 2 can also be configured with an independent current sensing resistor. This resistor is connected in series in the output path of each module, and its resistance value is very small, such as in the milliohm range. The synchronous rectification controller 21 can monitor the voltage drop across this resistor to obtain the current information of this channel, thereby realizing the overcurrent protection function of this channel and further improving the robustness of the entire system.

[0045] like Figure 4 As shown, it also includes a delay unit 2223, which is electrically connected to the logic controller 2222. When the logic controller 2222 issues a switching command, the delay unit 2223 will delay for a short period of time before sending it to the drive unit 223. The reason is that the MOSFET needs a certain amount of time to turn off. If the turn-off command is issued and the turn-on command of another MOSFET is issued immediately, the first MOSFET may not be completely turned off while the other MOSFET has started to conduct within a very short time. This will cause the transformer secondary winding to short-circuit instantaneously through the two MOSFETs, generating a huge spike current, which can easily damage the device.

[0046] like Figure 2 As shown, a power supply device includes a main circuit and the aforementioned multiphase independent synchronous rectifier. The output terminal of the main circuit is electrically connected to the input terminal of the power transformer 1 of the multiphase independent synchronous rectifier.

[0047] The multiphase independent synchronous rectifier serves as the secondary output of the power supply, while the main circuit can include the primary part of the power supply, such as the mains frequency AC input, power factor correction circuit, and high-frequency DC-DC converter, such as LLC resonant converter or phase-shifted full-bridge converter. The high-frequency AC output terminal of the DC-DC converter in the main circuit is connected to the input terminal of power transformer 1 in the multiphase independent synchronous rectifier, i.e., the primary winding of power transformer 1. The entire device works together to convert the mains power into a stable high-current DC power required by the server.

[0048] The aforementioned power supply equipment includes server power supplies, communication equipment power supplies, or computing equipment power supplies.

[0049] This invention is applicable to fields with high requirements for power density, efficiency, and reliability. Typical applications include server rack power supplies used in data centers, rectifier power modules for 5G communication base stations, and power supply units 221 for high-performance computing clusters used for scientific computing. These devices all require providing continuous and stable high-current output within a limited space, making them ideal application scenarios for the technical solution of this invention.

[0050] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A multiphase independent synchronous rectification device, characterized in that, include: A power transformer, wherein the power transformer includes at least two secondary output windings; At least two synchronous rectifier modules, the number of which corresponds to the number of secondary output windings, and the input terminal of each synchronous rectifier module is electrically connected to the corresponding secondary output winding. Each of the aforementioned synchronous rectification modules includes: Synchronous rectifier controller; A power transistor, wherein the main terminal of the power transistor is electrically connected to both ends of the secondary output winding, and the driving terminal of the power transistor is electrically connected to the synchronous rectifier controller; The output terminals of each synchronous rectification module are connected in parallel and used to supply power to the load uniformly. The output terminal of each synchronous rectification module is formed by the rectification of the power transistor inside it. The synchronous rectification controllers of each synchronous rectification module are electrically isolated from each other.

2. The multiphase independent synchronous rectification arrangement of claim 1, wherein, The number of synchronous rectification modules is three or more.

3. The multiphase independent synchronous rectification device as described in claim 1 or 2, characterized in that, The power transistor is a metal-oxide-semiconductor field-effect transistor with a positive temperature coefficient of on-resistance.

4. The multiphase independent synchronous rectification arrangement of claim 1, wherein, The synchronous rectifier controller and the power transistor are integrated into the same chip package.

5. The multiphase independent synchronous rectification arrangement of claim 1, wherein, It also includes a parallel output bus; One end of the parallel output bus is electrically connected to the output of the multiple synchronous rectification modules, and the other end of the parallel output bus is used to supply power to the load.

6. The multiphase independent synchronous rectification arrangement of claim 1, wherein, The input terminal of the synchronous rectifier controller of each synchronous rectifier module is electrically connected to the corresponding secondary output winding.

7. The multiphase independent synchronous rectifier as described in claim 2, characterized in that, The synchronous rectification controller includes a detection unit and a drive unit; The input terminal of the detection unit is electrically connected to the main terminal of the power transistor; The input terminal of the driving unit is electrically connected to the detection unit, and the output terminal of the driving unit is electrically connected to the control terminal of the power transistor. The detection unit is used to receive the voltage of the power transistor.

8. The multiphase independent synchronous rectification arrangement of claim 7, wherein, The detection unit includes a voltage comparator and a logic controller, the voltage comparator being electrically connected to the logic controller, and the logic controller being electrically connected to the drive unit; The input terminal of the voltage comparator is connected to the main terminal of the power transistor, and is used to compare the collected voltage of the power transistor with a preset threshold voltage, and output a level signal to the logic controller. The logic controller is used to receive the level signal and output a digital signal to the drive unit according to the level signal; The driving unit is used to receive the digital signal and drive the control terminal of the power transistor according to the digital signal.

9. A power supply device, characterized in that, It includes a main circuit and a multiphase independent synchronous rectifier as described in any one of claims 1 to 8, wherein the output terminal of the main circuit is electrically connected to the input terminal of the power transformer of the multiphase independent synchronous rectifier.

10. The power supply device as described in claim 9, characterized in that, The power supply device is a server power supply, a communication equipment power supply, or a computing equipment power supply.

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