Power supply circuit of autotransformer structure

Abstract

The application discloses a power supply circuit with a self-coupling transformer structure, which comprises a first resonant bridge, a second resonant bridge, a third resonant bridge, a fourth resonant bridge, a first coil unit, a second coil unit, a third coil unit and a capacitor. A voltage input end is located between the first resonant bridge and the second resonant bridge, the first resonant bridge is grounded through the third resonant bridge, the second resonant bridge is grounded through the fourth resonant bridge, and a reference ground is connected between the third resonant bridge and the fourth resonant bridge. The first resonant bridge is connected with the second resonant bridge through the capacitor and the first coil unit in sequence, the second coil unit is connected between the third resonant bridge and the third coil unit, and the third coil unit is connected on the fourth resonant bridge. A voltage output end is located between the second coil unit and the third coil unit and is used for outputting voltage to a load. The application realizes high integration and miniaturization of the power supply circuit by using the self-coupling transformer structure.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and more specifically, to a power supply circuit with an autotransformer structure. Background Technology

[0002] In traditional full-bridge DC-DC circuits, transformers are typically used for voltage conversion and electrical isolation, but the parallel winding of the secondary winding causes the transformer to occupy a large amount of space on the PCB board. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a power supply circuit with an autotransformer structure, addressing the large space occupation of existing full-bridge DC-DC circuit transformers on PCB boards.

[0004] The technical solution adopted by the present invention to solve its technical problem is: to construct a power supply circuit with an autotransformer structure, including: a first resonant bridge 10, a second resonant bridge 20, a third resonant bridge 30, a fourth resonant bridge 40, a first coil unit, a second coil unit, a third coil unit, and a capacitor;

[0005] The voltage input terminal is connected between the first terminal of the first resonant bridge 10 and the first terminal of the second resonant bridge 20. The second terminal of the first resonant bridge 10 is grounded through the first terminal of the third resonant bridge 30. The second terminal of the second resonant bridge 20 is grounded through the first terminal of the fourth resonant bridge 40. The reference ground is connected between the second terminal of the third resonant bridge 30 and the second terminal of the fourth resonant bridge 40.

[0006] The third end of the first resonant bridge 10 is also connected to the third end of the second resonant bridge 20 in sequence through the capacitor and the first coil unit;

[0007] The second end of the first resonant bridge 10 is also connected to the second end of the second resonant bridge 20; one end of the second coil unit is connected to the third end of the third resonant bridge 30, and the other end is connected to one end of the third coil unit, and the other end of the third coil unit is connected to the third end of the fourth resonant bridge 40; used to realize voltage transformation;

[0008] The voltage output terminal is connected between the second coil unit and the third coil unit, and is used to output the transformed voltage to the load.

[0009] In one embodiment, the first resonant bridge 10 includes a first switch SW1 and a second switch SW2;

[0010] The voltage input terminal is connected to the first end of the third resonant bridge 30 in sequence through the first switch SW1 and the second switch SW2. The first capacitor is connected between the first switch SW1 and the second switch SW2. The first switch SW1 is connected to the first end of the second resonant bridge 20.

[0011] In one embodiment, the second resonant bridge 20 includes a third switch SW3 and a fourth switch SW4;

[0012] The voltage input terminal is connected to the first terminal of the fourth resonant bridge 40 in sequence through the third switch SW3 and the fourth switch SW4. The first switch SW1 is connected to the third switch SW3. The first coil unit is connected between the third switch SW3 and the fourth switch SW4. The second switch SW2 is also connected to the fourth switch SW4.

[0013] In one embodiment, the third resonant bridge 30 includes a fifth switch SW5 and a sixth switch SW6; the second switch SW2 is grounded sequentially through the fifth switch SW5 and the sixth switch SW6, and the second coil unit is connected between the fifth switch SW5 and the sixth switch SW6.

[0014] In one embodiment, the fourth resonant bridge 40 includes a seventh switch SW7 and an eighth switch SW8; the fourth switch SW4 is grounded through the seventh switch SW7 and the eighth switch SW8 in sequence; the third coil unit is connected between the seventh switch SW7 and the eighth switch SW8; and the sixth switch SW6 is connected to the eighth switch SW8.

[0015] In one embodiment, the power supply circuit further includes a control circuit; the control circuit is connected to the control terminals of the first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, the fifth switch SW5, the sixth switch SW6, the seventh switch SW7, and the eighth switch SW8, respectively.

[0016] In one embodiment, the control circuit performs the following actions in one execution cycle: controlling the third switch SW3, the second switch SW2, the seventh switch SW7, and the sixth switch SW6 to turn on; and controlling the first switch SW1, the fourth switch SW4, the eighth switch SW8, and the fifth switch SW5 to turn off.

[0017] In one embodiment, the control circuit performs the following in one execution cycle: controlling the first switch SW1, the fourth switch SW4, the eighth switch SW8, and the fifth switch SW5 to be turned on, and controlling the third switch SW3, the second switch SW2, the seventh switch SW7, and the fifth switch SW5 to be turned off.

[0018] In one embodiment, the control circuit includes a PWM generator, which generates a corresponding pulse width modulation signal and frequency based on the operating frequency of the power supply circuit and the resonant frequency of the first coil, the second coil, and the capacitor under load conditions, for controlling the turn-on and turn-off times of each switching transistor.

[0019] In one embodiment, the switching transistor is any one of a silicon-based MOSFET device, a silicon carbide device, or a gallium nitride device.

[0020] The beneficial effect of this invention is that it provides a power supply circuit with an autotransformer structure, comprising: a first resonant bridge 10, a second resonant bridge 20, a third resonant bridge 30, a fourth resonant bridge 40, a first coil unit, a second coil unit, a third coil unit, and a capacitor; a voltage input terminal is connected between the first terminal of the first resonant bridge 10 and the first terminal of the second resonant bridge 20; the second terminal of the first resonant bridge 10 is grounded through the first terminal of the third resonant bridge 30; the second terminal of the second resonant bridge 20 is grounded through the first terminal of the fourth resonant bridge 40; and a reference ground is connected to the second terminal of the third resonant bridge 30 and the fourth resonant bridge 40. The second end of the first resonant bridge 10 is connected to the third end of the second resonant bridge 20 via the capacitor and the first coil unit; the second end of the first resonant bridge 10 is also connected to the second end of the second resonant bridge 20; one end of the second coil unit is connected to the third end of the third resonant bridge 30, and the other end is connected to one end of the third coil unit, and the other end of the third coil unit is connected to the third end of the fourth resonant bridge 40; this is used to realize voltage transformation; the voltage output terminal is connected between the second coil unit and the third coil unit, and is used to output the transformed voltage to the load. This invention achieves high integration and miniaturization of the power supply circuit by employing an autotransformer structure. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0022] Figure 1 This is a circuit diagram of a power supply circuit based on an embodiment of the autotransformer structure of the present invention;

[0023] Figure 2 This is a schematic diagram of a DC-DC circuit in the prior art;

[0024] Figure 3 This is a schematic diagram of the inductor current flow in an embodiment of a power supply circuit with an invented autotransformer structure.

[0025] Figure 4 This is a schematic diagram of the inductor current flow direction of another embodiment of the power supply circuit with the autotransformer structure. Detailed Implementation

[0026] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0027] like Figure 1 As shown, Figure 1 This is a circuit diagram of a power supply circuit based on an embodiment of the autotransformer structure of the present invention.

[0028] The technical solution adopted in this invention is a power supply circuit with an autotransformer structure, including: a first resonant bridge 10, a second resonant bridge 20, a third resonant bridge 30, a fourth resonant bridge 40, a first coil unit, a second coil unit, a third coil unit, and a capacitor;

[0029] The voltage input terminal is connected between the first terminal of the first resonant bridge 10 and the first terminal of the second resonant bridge 20. The second terminal of the first resonant bridge 10 is grounded through the third resonant bridge 30, and the second terminal of the second resonant bridge 20 is grounded through the fourth resonant bridge 40. The reference ground is connected between the second terminal of the third resonant bridge 30 and the second terminal of the fourth resonant bridge 40.

[0030] The third end of the first resonant bridge 10 is connected to the third end of the second resonant bridge 20 in sequence through a capacitor and the first coil unit; the second end of the first resonant bridge 10 is also connected to the second end of the second resonant bridge 20; one end of the second coil unit is connected to the third end of the third resonant bridge 30, and the other end is connected to one end of the third coil unit, and the other end of the third coil unit is connected to the third end of the fourth resonant bridge 40; this is used to realize voltage transformation; the voltage output terminal is connected between the second coil unit and the third coil unit, and is used to output the transformed voltage to the load.

[0031] like Figure 1 As shown, the present invention employs a power supply circuit with an autotransformer structure, including multiple resonant bridges and coil units. Specifically, N1A represents the first coil unit, N2A1 represents the second coil unit, and N2A2 represents the third coil unit. N2A1 and N2A2 are symmetrical coils with equal inductance values.

[0032] During circuit operation, the input voltage sequentially passes through switch SW3, the first coil unit N1A, switch SW2, switch SW7, the third coil unit N2A2, the second coil unit N2A1, and switch SW6, forming a resonant path. The resonant frequency of this path is determined by the total inductance of the first coil unit N1A, the second coil unit N2A1, and the third coil unit N2A2 (i.e., N1A + N2A1 + N2A2) and the capacitance C.

[0033] In the next switching cycle, the input voltage passes sequentially through switch SW1, capacitor C, first coil unit N1A, switch SW4, switch SW5, second coil unit N2A1, third coil unit N2A2, and switch SW8, forming another resonant path. This path not only achieves the resonant function but also decouples the coils composed of N1A, N2A1, and N2A2.

[0034] Ultimately, the magnitude of the output voltage is determined by the ratio between the inductance of the second coil unit N2A1 (or the third coil unit N2A2) and the total inductance of the entire coil (i.e., N1A + N2A1 + N2A2).

[0035] Furthermore, the first resonant bridge 10 includes a first switch SW1 and a second switch SW2; the voltage input terminal is connected to the first end of the third resonant bridge 30 in sequence through the first switch SW1 and the second switch SW2, the first capacitor is connected between the first switch SW1 and the second switch SW2, and the first switch SW1 is connected to the first end of the second resonant bridge 20.

[0036] In one embodiment, when the circuit is operating, voltage enters from the input terminal and first enters the first resonant bridge 10. The first switch SW1 and the second switch SW2 are alternately turned on and off according to a preset frequency and duty cycle.

[0037] Furthermore, the second resonant bridge 20 includes a third switch SW3 and a fourth switch SW4; the voltage input terminal is connected to the first end of the fourth resonant bridge 40 in sequence through the third switch SW3 and the fourth switch SW4, the first switch SW1 is connected to the third switch SW3, the first coil unit is connected between the third switch SW3 and the fourth switch SW4, and the second switch SW2 is also connected to the fourth switch SW4.

[0038] The first coil, along with the second and third coil units, resonate efficiently under the control of the switching transistor, achieving electromagnetic induction and further voltage transformation. This improves energy conversion and transmission efficiency, reduces losses, and optimizes overall performance. Compared to traditional transformer winding structures, this combination simplifies the circuit structure, reduces components and PCB area, lowers costs, and increases integration and miniaturization, meeting the high requirements of modern electronic devices for power circuits.

[0039] Furthermore, the third resonant bridge 30 includes a fifth switch SW5 and a sixth switch SW6; the second switch SW2 is grounded in sequence through the fifth switch SW5 and the sixth switch SW6, and the second coil unit is connected between the fifth switch SW5 and the sixth switch SW6.

[0040] Furthermore, the fourth resonant bridge 40 includes a seventh switch SW7 and an eighth switch SW8; the fourth switch SW4 is grounded through the seventh switch SW7 and the eighth switch SW8 in sequence, the third coil unit is connected between the seventh switch SW7 and the eighth switch SW8, and the sixth switch SW6 is connected to the eighth switch SW8.

[0041] like Figure 2 The diagram shows a traditional full-bridge DC-DC circuit. It uses a total of four coils: N1, N2, N3, and N4. After adopting the implementation idea of ​​an autotransformer, the improved circuit is shown below. Figure 3 As shown in the diagram. In specific implementations, assuming that N1 and N2 are not equal to N3 and N4, the least common divisor method can be used to ensure that the number of turns of N2A1 and N2A2 in the improved diagram is one-in-one of the smallest integer fractions of the number of turns of N1, N2, N3, and N4 before the improvement. For example: N1=N2=2, N3=N4=1. Then after the improvement, N2A1=1, N2A2=1, and N1A=2. The total number of turns of the coil before the improvement is 2+2+1+1=6, and the number of turns of the coil after the improvement is 2+1+1=4. The number of turns saved is 2, and the saving rate is 2 / 6=33.3%.

[0042] Furthermore, the power supply circuit also includes a control circuit; the control circuit is connected to the control terminals of the first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, the fifth switch SW5, the sixth switch SW6, the seventh switch SW7, and the eighth switch SW8, respectively.

[0043] It should be noted that the control circuit is responsible for controlling the on and off states of each switching transistor based on the operating status of the power supply circuit and load requirements. It monitors parameters such as voltage and current in the circuit and adjusts the drive signals of the switching transistors in real time to ensure the circuit maintains optimal operation under different working conditions. For example, when the load changes, the control circuit can respond quickly, adjusting the on-time of the switching transistors to maintain stable output voltage. Simultaneously, the control circuit also has protection functions, such as overcurrent protection and overvoltage protection. When abnormal conditions are detected, it can promptly shut down the relevant switching transistors to prevent circuit damage.

[0044] like Figure 3 As shown in Figure 4, where Figure 3 The direction of the inductor current is from left to right. Figure 4 The direction of the inductor current is from right to left, such as... Figure 3 and Figure 4 The two stages shown are mutually switched, and the switching transistor is used to commutate the current in the inductor to maintain volt-second balance. Specifically, when the circuit is in... Figure 3 During the stage shown, the control circuit turns on the relevant switching transistors, forming a current path from left to right, and the inductor stores energy; subsequently, the circuit switches to... Figure 4 In the stage shown, the control circuit changes the conduction state of the switching transistor, reversing the current direction so that it flows from right to left, and the inductor releases energy. Through this mutual conversion between the two stages, the inductor current is reversed, thereby maintaining the volt-second balance of the inductor and ensuring the stable operation of the circuit.

[0045] Furthermore, the control circuit executes the following in one execution cycle: controlling the third switch SW3, the second switch SW2, the seventh switch SW7 and the sixth switch SW6 to turn on, and controlling the first switch SW1, the fourth switch SW4, the eighth switch SW8 and the fifth switch SW5 to turn off.

[0046] It should be noted that this control strategy ensures that the current flows through the circuit along a predetermined path. When the third switch SW3 and the second switch SW2 are turned on, the current flows from the input terminal through the third switch SW3 to the first coil unit, and then through the second switch SW2 to the subsequent circuit. Simultaneously, the conduction of the seventh switch SW7 and the sixth switch SW6 allows the current to flow through the third coil unit to the ground terminal, completing the current loop. At this time, the off state of the first switch SW1, the fourth switch SW4, the eighth switch SW8, and the fifth switch SW5 ensures that the current does not flow along other paths, avoiding unnecessary energy loss and circuit interference.

[0047] Furthermore, the control circuit executes the following in one execution cycle: controlling the first switch SW1, the fourth switch SW4, the eighth switch SW8 and the fifth switch SW5 to turn on, and controlling the third switch SW3, the second switch SW2, the seventh switch SW7 and the fifth switch SW5 to turn off.

[0048] It should be noted that this control strategy ensures that the current flows through the circuit along a predetermined path. When the first switch SW1 is turned on, the current flows from the input terminal through the first switch SW1 to the first terminal of the second resonant bridge 20. The conduction of the fourth switch SW4 allows the current to continue flowing to the fourth resonant bridge 40, and finally to ground through the eighth switch SW8 and the fifth switch SW5. At this time, the off state of the third switch SW3, the second switch SW2, the seventh switch SW7, and the sixth switch SW6 ensures that the current does not flow to other paths, avoiding unnecessary energy loss and circuit interference.

[0049] Furthermore, the control circuit includes a PWM generator. The PWM generator generates corresponding pulse width modulation signals and frequencies based on the operating frequency of the power supply circuit, the load conditions, and the resonant frequencies of the first coil, the second coil, and the capacitor, which are used to control the on and off times of each switching transistor.

[0050] Specifically, the PWM generator monitors the operating status of the power supply circuit in real time, including the operating frequency and load conditions, while also considering the resonant frequencies of the first coil, the second coil, and the capacitor. These parameters collectively determine the characteristics of the pulse width modulation signal. The generated pulse width modulation signal is then sent to the control terminals of each switch transistor to precisely control the turn-on and turn-off times of the transistors. For example, within one execution cycle, the PWM generator may control the first switch transistor SW1, the fourth switch transistor SW4, the eighth switch transistor SW8, and the fifth switch transistor SW5 to turn on, while controlling the third switch transistor SW3, the second switch transistor SW2, the seventh switch transistor SW7, and the sixth switch transistor SW6 to turn off, thereby guiding the current to flow along a predetermined path and achieving efficient voltage conversion and current transfer.

[0051] Furthermore, the switching transistor is any one of a silicon-based MOSFET device, a silicon carbide device, or a gallium nitride device.

[0052] This invention utilizes an autotransformer model to cleverly reuse the primary winding of the transformer, reducing the number of parallel turns in the secondary winding. Each turn of the transformer's primary winding serves as the smallest unit. Based on the design of the transformer and switching power supply, the number of secondary windings is determined by stacking N of these smallest units as part of the secondary winding. This achieves the goal of reducing the wire diameter of the secondary winding and improving the power density of the electrically non-isolated power supply.

[0053] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, free combinations of the above technical features and various modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A power supply circuit with an autotransformer structure, characterized in that, include: First resonant bridge (10), second resonant bridge (20), third resonant bridge (30), fourth resonant bridge (40), first coil unit, second coil unit, third coil unit and capacitor; The voltage input terminal is connected between the first end of the first resonant bridge (10) and the first end of the second resonant bridge (20). The second end of the first resonant bridge (10) is grounded through the first end of the third resonant bridge (30). The second end of the second resonant bridge (20) is grounded through the first end of the fourth resonant bridge (40). The reference ground is connected between the second end of the third resonant bridge (30) and the second end of the fourth resonant bridge (40). The third end of the first resonant bridge (10) is also connected to the third end of the second resonant bridge (20) in sequence through the capacitor and the first coil unit; The second end of the first resonant bridge (10) is also connected to the second end of the second resonant bridge (20) to cooperate with the first coil unit, the second coil unit, the third coil unit and the capacitor to form a resonant path that reuses the second coil unit and the third coil unit; One end of the second coil unit is connected to the third end of the third resonant bridge (30), and the other end is connected to one end of the third coil unit. The other end of the third coil unit is connected to the third end of the fourth resonant bridge (40); used to realize voltage transformation. The voltage output terminal is connected between the second coil unit and the third coil unit, and is used to output the transformed voltage to the load.

2. The power supply circuit with an autotransformer structure according to claim 1, characterized in that, The first resonant bridge (10) includes a first switch (SW1) and a second switch (SW2); The voltage input terminal is connected to the first end (30) of the third resonant bridge in sequence through the first switch (SW1) and the second switch (SW2). The capacitor is connected between the first switch (SW1) and the second switch (SW2). The first switch (SW1) is connected to the first end of the second resonant bridge (20).

3. The power supply circuit with an autotransformer structure according to claim 2, characterized in that, The second resonant bridge (20) includes a third switch (SW3) and a fourth switch (SW4); The voltage input terminal is connected to the first end of the fourth resonant bridge (40) in sequence through the third switch (SW3) and the fourth switch (SW4). The first switch (SW1) is connected to the third switch (SW3). The first coil unit is connected between the third switch (SW3) and the fourth switch (SW4). The second switch (SW2) is also connected to the fourth switch (SW4).

4. The power supply circuit with an autotransformer structure according to claim 3, characterized in that, The third resonant bridge (30) includes a fifth switch (SW5) and a sixth switch (SW6). The second switch (SW2) is grounded in sequence through the fifth switch (SW5) and the sixth switch (SW6), and the second coil unit is connected between the fifth switch (SW5) and the sixth switch (SW6).

5. The power supply circuit with an autotransformer structure according to claim 4, characterized in that, The fourth resonant bridge (40) includes a seventh switch (SW7) and an eighth switch (SW8). The fourth switch (SW4) is grounded in sequence through the seventh switch (SW7) and the eighth switch (SW8). The third coil unit is connected between the seventh switch (SW7) and the eighth switch (SW8). The sixth switch (SW6) is connected to the eighth switch (SW8).

6. The power supply circuit with an autotransformer structure according to claim 5, characterized in that, The power supply circuit also includes a control circuit; The control circuit is connected to the control terminals of the first switch (SW1), the second switch (SW2), the third switch (SW3), the fourth switch (SW4), the fifth switch (SW5), the sixth switch (SW6), the seventh switch (SW7), and the eighth switch (SW8), respectively.

7. The power supply circuit with an autotransformer structure according to claim 6, characterized in that, The control circuit executes in one execution cycle: Control the conduction of the third switch (SW3), the second switch (SW2), the seventh switch (SW7), and the sixth switch (SW6). The first switch (SW1), the fourth switch (SW4), the eighth switch (SW8), and the fifth switch (SW5) are turned off.

8. The power supply circuit with an autotransformer structure according to claim 6, characterized in that, The control circuit executes in one execution cycle: The first switch (SW1), the fourth switch (SW4), the eighth switch (SW8), and the fifth switch (SW5) are turned on, while the third switch (SW3), the second switch (SW2), the seventh switch (SW7), and the fifth switch (SW5) are turned off.

9. The power supply circuit with an autotransformer structure according to claim 6, characterized in that, The control circuit includes a PWM generator, which generates corresponding pulse width modulation signals and frequencies based on the operating frequency of the power supply circuit, the load conditions, and the resonant frequencies of the first coil, the second coil, and the capacitor, to control the on and off times of each switching transistor.

10. The power supply circuit with an autotransformer structure according to claim 6, characterized in that, The switching transistor can be any one of a silicon-based MOSFET device, a silicon carbide device, or a gallium nitride device.

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