Low-voltage input high-power isolation power supply based on GaN power tube

Abstract

The invention discloses a GaN power tube-based low-voltage input high-power isolated power supply, which comprises a first-stage circuit and a second-stage circuit, the first-stage circuit and the second-stage circuit both adopt a GaN power tube as a main power switch in a circuit, the first-stage circuit and the second-stage circuit are connected in series, and the input end of the first-stage circuit is used as the input end of the high-power isolated power supply; the output end of the second-stage circuit is used as the output end of the high-power isolation power supply; the first-stage circuit is used for boosting an input low-voltage direct-current voltage through an interleaved parallel BOOST circuit to obtain a boosted voltage; and the second-stage circuit is used for converting the boosted voltage into a voltage required by a load by adopting an asymmetric half-bridge flyback AHB topology and then outputting the voltage, and isolating the input boosted voltage from the output voltage required by the load through a power transformer. The switching power supply provided by the invention can meet the requirements of low-voltage input, high-power output, input and output voltage isolation, high efficiency, low temperature rise and high integration.

Description

Technical Field

[0001] The present invention belongs to the technical field of switching power supplies, and in particular relates to a high-power isolation power supply with low voltage input based on a GaN power tube. Background Art

[0002] As an indispensable power supply module for electronic products, switching power supplies appear in various electronic products. Switching power supplies can convert the power supply voltage from the outside into the required load voltage of the actual device to be powered, and at the same time need to meet the current requirements of the device to be powered under different working conditions. For actual electronic products, some electronic products often require the power supply voltage to be isolated from other external voltages according to the actual application, and they do not share the same ground. At this time, it is necessary to consider using an isolated switching power supply. Secondly, with the development of electronic products, the required current of the devices to be powered (for example, power amplifier devices, load chips, etc.) continues to increase, and a switching power supply that can provide greater power is needed. Usually, more complex switching power supply circuits are selected during design, such as LLC resonant conversion circuits (L in LLC represents resonant inductance and excitation inductance, and C represents resonant capacitance) or phase-shifted full-bridge circuits. From the perspective of circuit design, this type of power supply has more complex circuits, more circuit components, and increased difficulty in power supply design. From the perspective of circuit size structure, in addition to the newly added functional circuits of each link, larger energy storage inductors, larger packages and larger heat dissipation surfaces of power devices are required. At the same time, heat dissipation treatment is required at the places where the temperature rise of the power supply is high (for example, applying thermal conductive glue, adding heat sinks, etc.), so that the overall size of the overall power supply will be larger. Correspondingly, with the development of power supply technology, many power supply designs increase the switching frequency of the power supply, thereby reducing the inductance of the transformer or inductor and the size of the transformer (inductor) in the hope of reducing the size of the overall power supply module. However, for the commonly used Si-based MOSFET switch tube (MOSFET is a metal-oxide semiconductor field-effect transistor, and the full name of MOSFET in English is Metal-Oxide-Semiconductor Field-EffectTransistor), there are generally conduction losses and switching losses, among which the switching losses are positively correlated with the switching frequency of the power supply circuit. When the switching frequency increases to a certain extent, the switching loss of the Si-based MOSFET is already quite large. At this time, if no heat dissipation measures are added, the power MOSFET tube will be damaged due to overheating. Therefore, it is necessary to consider adding design heat dissipation measures, which increases the size of the power supply.

[0003] The development of electronic products conforms to the overall trend of increasing power and decreasing size. As a link in the overall electronic product, the switching power supply also needs to reduce its own size and meet higher power density. Therefore, the design of the switching power supply needs to take into account the above issues. In particular, for low-voltage DC input scenarios (for example, external 18V / 24V / 28V bus power supply), when the terminal power demand is large, the current in the circuit will increase accordingly. The increase in current will further increase the loss of power devices (especially the switch MOSFET), and the miniaturization design of the power supply will be further difficult. For example, the common isolated power supply topology flyback converter will no longer be so applicable above 150W.

[0004] In other words, there is an urgent need to design a switching power supply to meet the requirements of low voltage input, high power output, input and output voltage isolation, high efficiency, low temperature rise and high integration. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a high-power isolation power supply with low voltage input based on GaN power tube.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solutions: The present invention provides a low-voltage input high-power isolated power supply based on a GaN power tube, comprising: a first-stage circuit and a second-stage circuit, wherein the output end of the first-stage circuit is connected to the input end of the second-stage circuit, the input end of the first-stage circuit serves as the input end of the high-power isolated power supply, and the output end of the second-stage circuit serves as the output end of the high-power isolated power supply; The first-stage circuit is used to raise the input low-voltage DC voltage by interleaving and paralleling BOOST boost circuits to obtain a boosted voltage; The second stage circuit is used to adopt an asymmetric half-bridge flyback AHB topology to convert the boosted voltage into a voltage required by the load and then output it, and isolate the input boosted voltage from the output voltage required by the load through a power transformer; Wherein, both the first-stage circuit and the second-stage circuit use GaN power tubes as main power switches in the circuit.

[0007] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a two-stage architecture to design a low-voltage input, high-power isolated power supply. Specifically, the input low-voltage DC voltage can be raised through the first-stage circuit, for example, it can be raised to about 100V, and then the raised voltage is used as the input of the second-stage circuit. Due to the voltage rise, when the output power is constant, the input current in the second-stage circuit can be greatly reduced. According to the MOSFET conduction loss being proportional to the effective value current flowing through the MOSFET, the present invention can significantly reduce the conduction loss of the main power MOSFET. In addition, the second-stage circuit of the present invention uses a transformer to achieve the isolation of the output voltage from the input voltage, thereby meeting the needs of the power supply design with input and output isolated from each other; at the same time, the second-stage circuit of the present invention adopts an asymmetric half-bridge flyback AHB topology, so that a certain amount of energy can be transferred by using the resonant energy storage capacitor therein, which increases the energy transfer in the power supply circuit and also improves the power density of the power supply circuit designed by the present invention. In addition, the present invention uses GaN power tubes to design switching power supplies, and utilizes the characteristics of fast switching speed and low loss of GaN devices under high-frequency switching in the power supply design; when working at high frequency, due to the fast switching speed of GaN devices, the turn-on and turn-off time of the GaN power tube can be shortened, and the two indicators of turn-on and turn-off time are positively correlated with the turn-on and turn-off losses of the GaN power tube. Therefore, the switching loss of the power switch GaN in the present invention is also optimized, thereby optimizing the loss of the overall power supply circuit, so that the reduction of circuit loss does not require more heat sinks, heat dissipation areas or measures, thereby saving the area of ​​the overall power supply circuit and improving the power density of the power supply circuit.

[0008] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a circuit structure schematic diagram of a GaN power tube-based low-voltage input high-power isolated power supply provided by an embodiment of the present invention; Figure 2 is a circuit schematic diagram of a first-stage circuit provided by an embodiment of the present invention; Figure 3 is a specific circuit connection principle diagram of the first-level circuit provided by an embodiment of the present invention; Figure 4 is a circuit schematic diagram of a second-stage circuit provided by an embodiment of the present invention; Figure 5 It is a specific circuit connection principle diagram of the second-level circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0010] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0011] Figure 1 1 is a circuit structure schematic diagram of a GaN power tube low voltage input high power isolated power supply provided by an embodiment of the present invention. Figure 1 As shown, the high-power isolated power supply includes: a first-stage circuit and a second-stage circuit, wherein the output end of the first-stage circuit is connected to the input end of the second-stage circuit, the input end of the first-stage circuit serves as the input end of the high-power isolated power supply, and the output end of the second-stage circuit serves as the output end of the high-power isolated power supply. The first-stage circuit is used to raise the input low-voltage DC voltage through an interlaced parallel BOOST boost circuit to obtain a boosted voltage. The second-stage circuit is used to convert the boosted voltage into the voltage required by the load using an asymmetric half-bridge flyback AHB topology (AHB's full English spelling is Asymmerical Half-Bridge, and its Chinese meaning is asymmetric half-bridge) and then output it, and isolate the input boosted voltage from the output voltage required by the load through a power transformer. Both the first-stage circuit and the second-stage circuit use GaN power tubes as the main power switches in the circuit.

[0012] The present invention uses GaN power tubes to build a switching power supply, optimizes the turn-on and turn-off losses of the power device, and improves the efficiency of the overall power supply. Therefore, the low-voltage input high-power isolated power supply based on GaN power tubes provided by the present invention is a high-efficiency power module. The present invention uses GaN power devices to build a switching power supply, optimizes the loss of the overall circuit, reduces the heat dissipation area of ​​the power supply, and enables the power supply to operate at a higher power under the same volume, thereby enabling the power supply to have a higher power density. In addition, the present invention optimizes the high-frequency characteristics of the power device of each level of the circuit by making the main power switching device of each level of the circuit use GaN power tubes, reduces the loss of the power tube of each level of the circuit, and thus provides a multi-level architecture power supply designed using GaN devices.

[0013] In some embodiments, the first-stage circuit includes: a first BOOST boost circuit and a second BOOST boost circuit, and the input end of the first BOOST boost circuit and the input end of the second BOOST boost circuit are connected as the input end of the first-stage circuit, the output end of the first BOOST boost circuit and the output end of the second BOOST boost circuit are connected as the output end of the first-stage circuit, and the control end of the first BOOST boost circuit and the control end of the second BOOST boost circuit are also connected.

[0014] Specifically, the first BOOST boost circuit includes: a first filter module, a first power control chip U1, a first GaN driver chip U3, a first power inductor L1 and a first GaN power tube module; wherein the first filter module, the first power inductor L1 and the first GaN power tube module are connected, the first power control chip U1, the first GaN driver chip U3 and the first GaN power tube module are connected, and the first filter module and the first GaN power tube module are also grounded. Specifically, the second BOOST boost circuit includes: a second filter module, a second power control chip U2, a second GaN driver chip U4, a second power inductor L2 and a second GaN power tube module; wherein the second filter module, the second power inductor L2 and the second GaN power tube module are connected, the second power control chip U2, the second GaN driver chip U4 and the second GaN power tube module are connected, and the second filter module and the second GaN power tube module are also grounded. One end of the first filter module is connected to one end of the second filter module to realize the connection between the input end of the first BOOST boost circuit and the input end of the second BOOST boost circuit. The other end of the first filter module, the first GaN power tube module, the other end of the second filter module and the second GaN power tube module are connected to realize the connection between the output end of the first BOOST boost circuit and the output end of the second BOOST boost circuit. The first power control chip U1 is connected to the second power control chip U2 to realize the connection between the control end of the first BOOST boost circuit and the control end of the second BOOST boost circuit. It should be noted that the inductance and model of L1 and L2 are the same.

[0015] Here, the first power control chip U1 is used to send a control signal to the first GaN driver chip U3, and the first GaN driver chip U3 is used to convert the received drive signal into the drive voltage of the GaN power tube in the first GaN power tube module to control the opening and closing of the GaN power tube in the first GaN power tube module. The second power control chip U2 is used to send a control signal to the second GaN driver chip U4, and the second GaN driver chip U4 is used to convert the received drive signal into the drive voltage of the GaN power tube in the second GaN power tube module to control the opening and closing of the GaN power tube in the second GaN power tube module. It should be noted that U1 and U2 are both chips with staggered parallel BOOST mode control function, so that the first-level circuit can realize the operation of staggered parallel BOOST mode, and U1 and U2 are of the same model, and U3 and U4 are also of the same model. In addition, one of U1 and U2 is a main control chip, and the other is an auxiliary control chip; for example, in the present invention, U1 is used as the main control chip and U2 is used as the auxiliary control chip.

[0016] For example, Figure 2 is a circuit schematic diagram of the first-level circuit. Figure 2 As shown, the first filter module includes: input filter capacitor C1, output filter capacitor C3; the first GaN power tube module includes: GaN power tube Q1, GaN power tube Q2. The second filter module includes: input filter capacitor C2, output filter capacitor C4; the second GaN power tube module includes: GaN power tube Q3, GaN power tube Q4. Specifically, as Figure 2 As shown, one end of C1 is connected to one end of C2, and the end of C1 connected to C2 is also connected to one end of L1, and the other end of L1 is simultaneously connected to the drain of Q1 and the source of Q2, the gate of Q2 is connected to the first control output end of U3, the drain of Q2 is simultaneously connected to one end of C3, one end of C4 and the drain of Q4, the other end of C3 and the other end of C4 are both grounded, the gate of Q1 is connected to the second control output end of U3, the source of Q1 is grounded, and the control output end of U1 is connected to the control input end of U3; U1 is connected to U2, the control output end of U2 is connected to the control input end of U4, the first control output end of U4 is connected to the gate of Q4, the source of Q4 is simultaneously connected to one end of L2 and the drain of Q3, the other end of L2 is connected to the ungrounded end of C2, the second control output end of U4 is connected to the gate of Q3, and the source of Q3 is grounded. The ungrounded end of C1 serves as the input end of the first BOOST boost circuit, and the ungrounded end of C2 serves as the input end of the second BOOST boost circuit; the drain of Q2 serves as the output end of the first BOOST boost circuit, and the drain of Q4 serves as the output end of the second BOOST boost circuit; the ends connected to U1 and U2 serve as the control end of the first BOOST boost circuit and the control end of the second BOOST boost circuit respectively, and one of U1 and U2 is the main control chip, and the other is the auxiliary control chip.

[0017] It should be noted that the specifications of C1 and C2 are the same, and the specifications of C3 and C4 are the same.

[0018] Here, the input of the first stage circuit is a low voltage input voltage provided by the outside world, for example, a common bus low voltage power supply such as 18V, 24V, 28V, etc. The two BOOST boost circuits can realize the staggered parallel boost control of the two BOOST boost circuits through U1 and U2 with the same function. The driving voltage range of the GaN device is small (usually less than 8V), and the driving control is relatively sensitive and easily interfered by the outside world. Therefore, the present invention uses GaN dedicated driver chips U3 and U4 to provide driving control for the GaN switch tube to control the opening and closing of the corresponding GaN switch tube, which can meet the driving voltage range of the GaN power tube and ensure the reliability of the GaN device switch. The first stage circuit in the present invention can convert the input low voltage power supply into a high voltage boost power supply to power the second stage circuit, so that the current can be reduced by increasing the voltage during high power output, thereby reducing the power MOSFET conduction loss caused by the current. On the other hand, for high-power applications, the present invention adopts an interlaced parallel BOOST circuit structure, which can evenly distribute the power of the overall power supply to two BOOST boost circuits, so that the power MOSFET in each BOOST boost circuit only needs to bear half of the power, thereby optimizing the power loss of the MOSFET in each BOOST boost circuit and the temperature rise caused by the loss. In addition, when the GaN power tube in the first-stage circuit works at a high frequency, the opening and closing speeds are fast, so the opening and closing time are short, and since the opening and closing time of the power tube is positively correlated to the opening and closing losses of the power tube, the opening and closing losses of the GaN power tube in the first-stage circuit are small. In other words, the present invention optimizes the loss of the power tube in the power supply circuit through the design of the first-stage circuit, can reduce the temperature rise of the device due to the loss, thereby reducing the area of ​​circuit heat dissipation, and improving the power density of the power supply circuit, which can be suitable for power supply application scenarios with higher power.

[0019] For example, Figure 3 This is a specific circuit connection schematic diagram of the first-level circuit. Figure 3As shown, the drive signal output pin HO of U1 is connected to the drive signal input pin HI of U3, the drive signal output pin LO of U1 is connected to the drive signal input pin LI of U3, the drive output pin HS of U3 is connected to the gate of Q2, and the drive output pin LS of U3 is connected to the gate of Q1; the input undervoltage control pin UVLO of U1 is connected to the input undervoltage control pin UVLO of U2, the slow start control pin SS of U1 is connected to the slow start control pin SS of U2, the loop compensation pin COMP of U1 is connected to the loop compensation pin COMP of U2, and the staggered parallel synchronous control output of U1 is connected to the gate of Q2. The function pin SYNOUT is connected to the staggered parallel synchronization control input function pin SYNIN of U2, the staggered parallel synchronization control input function pin SYNIN of U1 can set the operating frequency of the first stage circuit by connecting an external resistor, and the staggered parallel synchronization control output function pin SYNOUT of U2 is suspended; the drive signal output pin HO of U2 is connected to the drive signal input pin HI of U4, the drive signal output pin LO of U2 is connected to the drive signal input pin LI of U4, the drive output pin HS of U4 is connected to the gate of Q4, and the drive output pin LS of U4 is connected to the gate of Q3.

[0020] Exemplarily, Q1, Q2, Q3 and Q4 may preferably use power devices with small on-resistance, for example, 1 mΩ, and GaN devices with fast switching speed, which may have better switching characteristics and thus smaller power device losses.

[0021] In some embodiments, the second stage circuit includes: a third filter module, a resonant energy storage capacitor, a power transformer T1, a third GaN power tube module, an asymmetric half-bridge flyback AHB control chip U5, a third GaN driver chip U6, a power tube module and a synchronous rectification control chip U7. The third filter module, the resonant energy storage capacitor, the power transformer T1, the third GaN power tube module, the power tube module and the synchronous rectification control chip U7 are connected, the asymmetric half-bridge flyback AHB control chip U5, the third GaN driver chip U6 and the third GaN power tube module are connected, and the third filter module and the third GaN power tube module are also grounded; one end of the third filter module connected to the resonant energy storage capacitor is used as the input end of the second stage circuit, and one end of the third filter module connected to the power tube module is used as the output end of the second stage circuit.

[0022] Here, the asymmetric half-bridge flyback AHB control chip U5 is used to send a drive control signal to the third GaN driver chip U6, and the third GaN driver chip U6 is used to convert the received drive control signal into the drive voltage of the GaN power tube in the third GaN power tube module to control the opening and closing of the GaN power tube in the third GaN power tube module. The synchronous rectification control chip U7 is used to control the opening and closing of the power tube in the power tube module, so that the power tube meets the working logic of the AHB circuit. It should be noted that U6 can be the same model as the above-mentioned U3 and U4. It should be noted that the chips used in the present invention are all existing chips.

[0023] For example, Figure 4 is a circuit schematic diagram of the second-stage circuit. Figure 4 As shown, the power tube module includes: power tube Q5 and power tube Q6, and Q5 and Q6 are connected in parallel by MOSFET. In the present invention, Q5 and Q6 are connected in parallel by MOSFET, so that more current can flow through the power circuit of the present invention, thereby increasing the power range of the power circuit provided by the present invention. Figure 4 The third filter module includes: input filter capacitor C5, output filter capacitor C6; the resonant energy storage capacitor in the second stage circuit is C7; the third GaN power tube module includes: GaN power tube Q7, GaN power tube Q8. Specifically, Figure 5 is a specific circuit connection schematic diagram of the second-level circuit. Figure 5 As shown, one end of C5 is connected to one end of C7 and the drain of Q7 at the same time, the other end of C5 is grounded, the other end of C7 is connected to pin 1 of the primary side of the power transformer T1, the source of Q7 is connected to the drain of Q8 and pin 2 of the primary side of the power transformer T1 at the same time, the gate of Q7 is connected to the drive output pin HS of U6; the gate of Q8 is connected to the drive output pin LS of U6, and the source of Q8 is grounded; the voltage pin VCC of U5 is connected to the voltage pin VDD of U6, the enable signal pin EN of U5 is connected to the enable pin EN of U6, and the drive signal output pin HO of U5 is connected to The drive signal input pin HI of U6 is connected, and the drive signal output pin LO of U5 is connected to the drive signal input pin LI of U6; the source of Q5 is simultaneously connected to the source of Q6, the pin 4 of the secondary side of the power transformer T1, and the detection MOSFET source state control pin VS of U7, the gate of Q5 is simultaneously connected to the gate of Q6 and the drive output pin VG of U7, the drain of Q5 is simultaneously connected to the drain of Q6, the detection MOSFET drain state control pin VD of U7, and one end of C6, and the other end of C6 is connected to the pin 3 of the secondary side of the power transformer T1. In addition, as Figure 4 , Figure 5As shown, the other end of C6 can also be connected to the negative end of the load, so that the two ends of C6 can be connected to the two ends of the load to supply power to the load.

[0024] In the second-stage circuit of the present invention, the input voltage passes through the resonant energy storage capacitor C7, the primary side of the power transformer T1, and the GaN power tube Q8 in sequence, and then returns to the negative end of the input voltage. The secondary side of the power transformer T1 and the parallel GaN power tubes Q5 and Q6 cooperate with the synchronous rectification control chip U7 to form an output synchronous rectification circuit. Finally, the output of the secondary rectification circuit is the load required voltage output by the second-stage circuit of the present invention. In the second-stage circuit of the present invention, the power transformer T1 can be used to isolate the output load voltage from the input voltage, and can also be used as the main power storage and transfer device of the second-stage circuit; the use of the resonant energy storage capacitor C7 can increase the storage and transfer of energy in the AHB circuit. By adopting synchronous rectification at the output, the power supply circuit provided by the present invention is suitable for high-current and high-power scenarios; the output end adopts the method of parallel MOSFET Q5 and Q6 to further reduce the conduction loss of a single MOSFET. Different from the general flyback power supply circuit, the auxiliary GaN power tube Q7 is also added to the second-stage circuit of the present invention. The second-stage circuit of the present invention adopts an asymmetric half-bridge flyback AHB architecture, which can work in the two stages of transformer primary energy storage and transformer secondary energy supply for output. When working in the transformer primary energy storage stage, the GaN power tube Q8 is turned on, Q7 is turned off, and the input energy of the asymmetric half-bridge flyback AHB architecture is stored in the power transformer T1 and the resonant energy storage capacitor C7. When working in the stage where the transformer secondary side provides energy for the output, the GaN power tube Q8 is turned off, the auxiliary power tube Q7 is turned on, and the energy stored in the resonant capacitor C7 and the primary coil of the power transformer T1 is provided to the output load through the secondary side of the power transformer T1. The addition of the resonant energy storage capacitor C7 and the auxiliary power tube Q7 provides another part of the energy from the resonant energy storage capacitor C7 to the secondary side of the power transformer T1. Therefore, when a power transformer of the same specification is selected, the asymmetric half-bridge flyback AHB power supply architecture provided by the present invention will provide more energy, thereby improving the power density of the overall power supply circuit.

[0025] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0027] In the specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality of components. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good effects.

[0028] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A low-voltage input high-power isolated power supply based on GaN power tube, characterized in that: include: A first-stage circuit and a second-stage circuit, wherein the output end of the first-stage circuit is connected to the input end of the second-stage circuit, the input end of the first-stage circuit serves as the input end of the high-power isolated power supply, and the output end of the second-stage circuit serves as the output end of the high-power isolated power supply; The first-stage circuit is used to raise the input low-voltage DC voltage by interleaving and paralleling BOOST boost circuits to obtain a boosted voltage; The second stage circuit is used to adopt an asymmetric half-bridge flyback AHB topology to convert the boosted voltage into a voltage required by the load and then output it, and isolate the input boosted voltage from the output voltage required by the load through a power transformer; Wherein, both the first-stage circuit and the second-stage circuit use GaN power tubes as main power switches in the circuit.

2. The low-voltage input high-power isolated power supply based on GaN power tube according to claim 1 is characterized in that: The first-stage circuit includes: a first BOOST boost circuit and a second BOOST boost circuit, and the input end of the first BOOST boost circuit and the input end of the second BOOST boost circuit are connected to serve as the input end of the first-stage circuit, the output end of the first BOOST boost circuit and the output end of the second BOOST boost circuit are connected to serve as the output end of the first-stage circuit, and the control end of the first BOOST boost circuit and the control end of the second BOOST boost circuit are connected.

3. The low-voltage input high-power isolated power supply based on GaN power tube according to claim 2 is characterized in that: The first BOOST boost circuit includes: a first filter module, a first power control chip U1, a first GaN driver chip U3, a first power inductor L1 and a first GaN power tube module; wherein the first filter module, the first power inductor L1 and the first GaN power tube module are connected, the first power control chip U1, the first GaN driver chip U3 and the first GaN power tube module are connected, and the first filter module and the first GaN power tube module are also grounded; The second BOOST boost circuit includes: a second filter module, a second power control chip U2, a second GaN driver chip U4, a second power inductor L2 and a second GaN power tube module; wherein the second filter module, the second power inductor L2 and the second GaN power tube module are connected, the second power control chip U2, the second GaN driver chip U4 and the second GaN power tube module are connected, and the second filter module and the second GaN power tube module are also grounded; One end of the first filter module is connected to one end of the second filter module to realize the connection between the input end of the first BOOST boost circuit and the input end of the second BOOST boost circuit; the other end of the first filter module, the first GaN power tube module, the other end of the second filter module and the second GaN power tube module are connected to realize the connection between the output end of the first BOOST boost circuit and the output end of the second BOOST boost circuit; The first power control chip U1 is connected to the second power control chip U2 to achieve connection between the control end of the first BOOST boost circuit and the control end of the second BOOST boost circuit.

4. The low-voltage input high-power isolated power supply based on GaN power tube according to claim 3 is characterized in that: The first power control chip U1 is used to send a control signal to the first GaN driver chip U3, and the first GaN driver chip U3 is used to convert the received drive signal into a drive voltage of the GaN power tube in the first GaN power tube module to control the opening and closing of the GaN power tube in the first GaN power tube module; The second power control chip U2 is used to send a control signal to the second GaN driver chip U4, and the second GaN driver chip U4 is used to convert the received drive signal into a drive voltage of the GaN power tube in the second GaN power tube module to control the opening and closing of the GaN power tube in the second GaN power tube module.

5. The low-voltage input high-power isolated power supply based on GaN power tube according to claim 3 is characterized in that: The first filter module includes: an input filter capacitor C1 and an output filter capacitor C3; the first GaN power tube module includes: a GaN power tube Q1 and a GaN power tube Q2; The second filter module includes: an input filter capacitor C2 and an output filter capacitor C4; the second GaN power tube module includes: a GaN power tube Q3 and a GaN power tube Q4; One end of C1 is connected to one end of C2, and the end of C1 connected to C2 is also connected to one end of L1, and the other end of L1 is connected to the drain of Q1 and the source of Q2 at the same time, the gate of Q2 is connected to the first control output end of U3, the drain of Q2 is connected to one end of C3, one end of C4 and the drain of Q4 at the same time, the other end of C3 and the other end of C4 are both grounded, the gate of Q1 is connected to the second control output end of U3, the source of Q1 is grounded, and the control output end of U1 is connected to the control input end of U3; U1 is connected to U2, the control output end of U2 is connected to the control input end of U4, the first control output end of U4 is connected to the gate of Q4, the source of Q4 is connected to one end of L2 and the drain of Q3 at the same time, the other end of L2 is connected to the ungrounded end of C2, the second control output end of U4 is connected to the gate of Q3, and the source of Q3 is grounded; Among them, the ungrounded end of C1 serves as the input end of the first BOOST boost circuit, and the ungrounded end of C2 serves as the input end of the second BOOST boost circuit; the drain of Q2 serves as the output end of the first BOOST boost circuit, and the drain of Q4 serves as the output end of the second BOOST boost circuit; the ends connected to U1 and U2 serve as the control end of the first BOOST boost circuit and the control end of the second BOOST boost circuit respectively, and one of U1 and U2 is the main control chip, and the other is the auxiliary control chip.

6. The low-voltage input high-power isolated power supply based on GaN power tube according to claim 5 is characterized in that: Pin HO of U1 is connected to pin HI of U3, pin LO of U1 is connected to pin LI of U3, pin HS of U3 is connected to the gate of Q2, and pin LS of U3 is connected to the gate of Q1; pin UVLO of U1 is connected to pin UVLO of U2, pin SS of U1 is connected to pin SS of U2, pin COMP of U1 is connected to pin COMP of U2, pin SYNOUT of U1 is connected to pin SYNIN of U2, and pin SYNOUT of U2 is left floating; pin HO of U2 is connected to pin HI of U4, pin LO of U2 is connected to pin LI of U4, pin HS of U4 is connected to the gate of Q4, and pin LS of U4 is connected to the gate of Q3.

7. The GaN power tube-based low-voltage input high-power isolated power supply according to claim 1, characterized in that: The second stage circuit includes: a third filter module, a resonant energy storage capacitor, a power transformer T1, a third GaN power tube module, an asymmetric half-bridge flyback AHB control chip U5, a third GaN driver chip U6, a power tube module and a synchronous rectification control chip U7; Among them, the third filter module, the resonant energy storage capacitor, the power transformer T1, the third GaN power tube module, the power tube module and the synchronous rectification control chip U7 are connected, the asymmetric half-bridge flyback AHB control chip U5, the third GaN driver chip U6 and the third GaN power tube module are connected, and the third filter module and the third GaN power tube module are also grounded; one end of the third filter module and the resonant energy storage capacitor is connected as the input end of the second-stage circuit, and one end of the third filter module and the power tube module is connected as the output end of the second-stage circuit.

8. The low-voltage input high-power isolated power supply based on GaN power tube according to claim 7 is characterized in that: The asymmetric half-bridge flyback AHB control chip U5 is used to send a driving control signal to the third GaN driver chip U6, and the third GaN driver chip U6 is used to convert the received driving control signal into a driving voltage of the GaN power tube in the third GaN power tube module to control the opening and closing of the GaN power tube in the third GaN power tube module; The synchronous rectification control chip U7 is used to control the opening and closing of the power tube in the power tube module.

9. The low-voltage input high-power isolated power supply based on GaN power tube according to claim 7, characterized in that: The power tube module includes: a power tube Q5 and a power tube Q6, and Q5 and Q6 are connected in a MOSFET parallel connection manner.

10. The GaN power tube-based low-voltage input high-power isolated power supply according to claim 9, characterized in that: The third filter module includes: an input filter capacitor C5 and an output filter capacitor C6; the resonant energy storage capacitor in the second stage circuit is C7; the third GaN power tube module includes: a GaN power tube Q7 and a GaN power tube Q8; Among them, one end of C5 is connected to one end of C7 and the drain of Q7 at the same time, the other end of C5 is grounded, the other end of C7 is connected to pin 1 of the primary side of the power transformer T1 at the same time, the source of Q7 is connected to the drain of Q8 and pin 2 of the primary side of the power transformer T1 at the same time, the gate of Q7 is connected to pin HS of U6; the gate of Q8 is connected to pin LS of U6, and the source of Q8 is grounded; the pin VCC of U5 is connected to the pin VDD of U6, and the pin EN of U5 is connected to the pin HS of U6. The pin EN of U5 is connected, the pin HO of U5 is connected to the pin HI of U6, and the pin LO of U5 is connected to the pin LI of U6; the source of Q5 is connected to the source of Q6, the pin 4 of the secondary side of the power transformer T1, and the pin VS of U7 at the same time, the gate of Q5 is connected to the gate of Q6 and the pin VG of U7 at the same time, the drain of Q5 is connected to the drain of Q6, the pin VD of U7 and one end of C6 at the same time, and the other end of C6 is connected to the pin 3 of the secondary side of the power transformer T1.

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