TWI832416B - Power converter - Google Patents

Abstract

A power converter includes a primary-side rectifying/filtering circuit, an AC-DC converter, a DC/DC converter, a primary-side controller, a secondary-side rectification controller, and a secondary-side feedback controller. The primary-side rectifying/filtering circuit receives an input voltage, and rectifies and filters the input voltage into an adjusted input voltage. The AC-DC converter receives the adjusted input voltage. The primary-side controller provides a first control signal to control the AC-DC converter to convert the adjusted input voltage into a DC input voltage, and provides a second control signal to control the DC-DC converter. The secondary-side rectification controller provides a third control signal to control the DC-DC converter to convert the DC input voltage into a conversion voltage to supply power to a load based on a gain condition. The secondary-side feedback controller receives a power demand signal provided by the load to control the primary-side controller and the secondary-side rectification controller.

Description

power converter

The present invention relates to a power converter, in particular to a power converter that can operate in a half-bridge or full-bridge circuit topology and is used to provide multiple sets of output voltages of different sizes.

When the power is greater than 100 watts, power supply products usually use the PFC+LLC topology. The main reason is that LLC has zero-voltage switching characteristics, which allows the power supply product to operate at a higher frequency, thereby shrinking the magnetic components and reducing the energy consumption. Product volume.

The above-mentioned PFC as the first stage plus the second stage LLC is a very common power supply design architecture. However, in response to the increasing advancement of technology, there are many 3C products that require different voltages. Therefore, power supply product specifications with different output voltages have become an increasingly popular demand. However, since the optimal operating point of LLC efficiency is the resonant frequency point, a stable input voltage and a stable output voltage must be maintained at this resonant frequency point, so LLC is usually not the best solution at a single output voltage.

For this reason, how to design a power converter to solve the problems and technical bottlenecks of the existing technology is an important topic studied by the inventor of this case.

The purpose of the present invention is to provide a power converter to solve the problems of the prior art.

In order to achieve the aforementioned purpose, the power converter proposed by the present invention includes a primary side rectification filter circuit, an AC-to-DC converter, a DC-to-DC converter, a primary side controller, a secondary side rectification controller, and a secondary side feedback circuit. controller. The primary side rectifier and filter circuit receives the input voltage, and rectifies and filters the input voltage to output an adjusted input voltage. The AC-to-DC converter is coupled to the primary side rectifier and filter circuit and receives an adjusted input voltage. The DC-to-DC converter is coupled to the AC-to-DC converter. The primary-side controller is coupled to the AC-to-DC converter and the DC-to-DC converter, provides a first control signal to control the AC-to-DC converter to convert and adjust the input voltage into a DC input voltage, and provides a second control signal to control the DC-to-DC converter. . The secondary side rectifier controller is coupled to the DC-to-DC converter and provides a third control signal to control the DC-to-DC converter to convert the DC input voltage into a conversion voltage based on the gain condition to supply power to the load. The secondary side feedback controller is coupled to the primary side controller and the secondary side rectification controller. The secondary side feedback controller receives the load power supply demand signal provided by the load to control the operations of the primary side controller and the secondary side rectification controller. .

In one embodiment, the secondary side feedback controller provides a feedback control signal including an AC and DC feedback control signal and a DC and DC feedback control signal to the primary side controller, and provides a rectification control signal to the secondary side rectification control. device. The primary side controller controls the AC to DC converter according to the AC and DC feedback control signals, controls the DC to DC converter according to the DC and DC feedback control signals, and controls the secondary side rectification controller and adjusts the gain conditions according to the rectification control signals.

In one embodiment, the DC-to-DC converter includes a primary-side isolation circuit and a secondary-side isolation circuit. The primary-side isolation circuit is coupled to the AC-to-DC converter and the primary-side controller for receiving the second control signal and the DC input voltage. The secondary side isolation circuit is coupled to the secondary side rectifier controller and used to isolate and convert the DC input voltage.

In one embodiment, the primary-side isolation circuit includes a bridge switching circuit and a resonant circuit. The secondary side isolation circuit includes a bridge synchronous rectifier circuit and a buck conversion circuit.

In one embodiment, the bridge switching circuit includes an upper switch and a lower switch. The first end of the upper switch is coupled to the AC-to-DC converter. The first terminal of the lower switch is coupled to the second terminal of the upper switch and the resonant circuit. The primary side controller provides a second control signal to control the upper switch and the lower switch.

In one embodiment, the bridge synchronous rectifier circuit includes a first switch, a second switch, a third switch, a fourth switch, a first resonant inductor and a second resonant inductor. The first terminal of the second switch is coupled to the second terminal of the first switch. The first terminal of the third switch is coupled to the first terminal of the first switch and the buck conversion circuit. The first terminal of the fourth switch is coupled to the second terminal of the third switch. The first terminal of the first resonant inductor is coupled between the second terminal of the first switch and the first terminal of the second switch. The first end of the second resonant inductor is coupled to the second end of the first resonant inductor, and the second end of the second resonant inductor is coupled between the second end of the third switch and the first end of the fourth switch. The secondary side rectification controller provides a third control signal to control the first switch, the second switch, the third switch and the fourth switch.

In one embodiment, the bridge synchronous rectifier circuit further includes a first capacitor and a second capacitor. The first terminal of the first capacitor is coupled to the third switch. The first terminal of the second capacitor is coupled to the second terminal of the first capacitor, and the second terminal of the second capacitor is coupled to the fourth switch.

In one embodiment, the buck conversion circuit includes a fifth switch, a sixth switch, a diode, an inductor and a capacitor. The first terminal of the fifth switch is coupled to the first terminal of the third switch. The first terminal of the sixth switch is coupled between the second terminal of the first resonant inductor and the first terminal of the second resonant inductor, and the second terminal of the sixth switch is coupled to the second terminal of the fifth switch. The cathode of the diode is coupled to the second terminal of the fifth switch and the second terminal of the sixth switch. The first end of the inductor is coupled to the cathode of the diode. The first terminal of the capacitor is coupled to the second terminal of the inductor, and the second terminal of the capacitor is coupled to the anode of the diode and the second terminal of the fourth switch.

In one embodiment, when the conversion voltage is the first voltage, the first switch and the third switch are turned off, and the second switch and the fourth switch are switched on and off to excite the first resonant inductor or the second resonant inductor.

In one embodiment, when the second switch is turned on, a first magnetic excitation path is formed including the second switch, a first resonant inductor and a buck conversion circuit to excite the first resonant inductor. When the fourth switch It is turned on to form a second magnetic excitation path including a fourth switch, a second resonant inductor and a buck conversion circuit to excite the second resonant inductor.

In one embodiment, when the conversion voltage is the first voltage, the second switch and the fourth switch are turned off, and the first switch and the third switch are switched on and off to excite the first resonant inductor or the second resonant inductor.

In one embodiment, when the first switch is turned on, a third magnetic excitation path is formed including the first switch, the first resonant inductor and a buck conversion circuit to excite the first resonant inductor. When the third switch is turned on, a fourth magnetic excitation path is formed including the third switch, the second resonant inductor and the buck conversion circuit to excite the second resonant inductor.

In one embodiment, when the conversion voltage is the second voltage, the first switch and the fourth switch are turned on and off at the same time, the second switch and the third switch are turned on and off at the same time, and the first switch and the second switch interact with each other. The switch is turned on to excite the first resonant inductor and the second resonant inductor.

In one embodiment, when the first switch and the fourth switch are turned on at the same time, the first magnetic excitation path is formed including the first switch, the first resonant inductor, the second resonant inductor, the fourth switch and the buck conversion circuit. When the second switch and the third switch are turned on at the same time, a second magnetic excitation path is formed including the second switch, the first resonant inductor, the second resonant inductor, the third switch and the buck conversion circuit.

In one embodiment, when the conversion voltage is less than the first voltage, the fifth switch and the sixth switch turn on the buck conversion circuit.

In one embodiment, when the conversion voltage is less than the second voltage, the fifth switch and the sixth switch turn on the buck conversion circuit.

In one embodiment, the buck conversion circuit is used to convert the conversion voltage into a DC output voltage.

In one embodiment, by controlling the duty cycle of the fifth switch or the duty cycle of the sixth switch, the conversion voltage is stepped down into DC output voltages of different voltages.

The proposed power converter can operate in a half-bridge or full-bridge circuit topology to flexibly provide multiple sets of output voltages of different sizes.

In order to further understand the technology, means and effects adopted by the present invention to achieve the intended purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, features and characteristics of the present invention can be understood in depth and For specific understanding, however, the attached drawings are only for reference and illustration, and are not intended to limit the present invention.

1: Primary side rectifier and filter circuit

2: AC to DC converter

3: DC to DC converter

4: Primary side controller

5: Secondary side rectification controller

6: Secondary side feedback controller

7:Load

31: Primary side isolation circuit

32:Secondary side isolation circuit

311: Bridge switching circuit

312:Resonant circuit

321: Bridge synchronous rectifier circuit

322: Buck conversion circuit

Q _H : upper switch

Q _L : lower switch

Q1: First switch

Q2: Second switch

Q3: The third switch

Q4: The fourth switch

Q5: The fifth switch

Q6: The sixth switch

L1: first resonant inductor

L2: Second resonant inductor

C1: first capacitor

C2: second capacitor

D: Diode

L: inductance

C: capacitor

V _IN :Input voltage

V _INRF : adjust the input voltage

V _INDC : DC input voltage

V _CON :conversion voltage

V _OUTDC : DC output voltage

S _C1 : first control signal

S _C2 : Second control signal

S _C3 : The third control signal

_SLP : load power demand signal

S _CSR : Rectification control signal

S _CAD : AC and DC feedback control signal

S _CDD : DC feedback control signal

Figure 1: It is an architectural block diagram of the power converter of the present invention.

Figure 2 is a detailed block diagram of the power converter of the present invention.

Figures 3 and 4 are circuit diagrams of the DC-to-DC converter of the present invention.

The technical content and detailed description of the present invention are as follows with reference to the drawings.

Please refer to Figures 1 and 2, which are respectively an architectural block diagram and a detailed block diagram of the power converter of the present invention. The power converter with step-up and step-down conversion includes a primary side rectification and filter circuit 1, an AC to DC converter 2, a DC to DC converter 3, a primary side controller 4, a secondary side rectification controller 5 and a secondary side return circuit. Grant controller 6.

The primary side rectifier and filter circuit 1 receives the input voltage V _IN , and rectifies and filters the input voltage V _IN to output an adjusted input voltage V _INRF . Specifically, the primary side rectification and filter circuit 1 includes a primary side rectification circuit and a primary side filter circuit (not shown). The primary side rectifier circuit is used to rectify the input voltage V _IN . The primary side filter circuit is used to filter the rectified input voltage to output the adjusted input voltage V _INRF to the AC-to-DC converter 2 .

The AC-to-DC converter 2 is coupled to the primary-side rectifier and filter circuit 1 and receives the adjusted input voltage V _INRF output by the primary-side rectifier and filter circuit 1 .

The DC-to-DC converter 3 is coupled to the AC-to-DC converter 2 . Specifically, as shown in Figures 3 and 4, they are circuit diagrams of the DC-to-DC converter of the present invention. The DC-to-DC converter 3 includes a primary side isolation circuit 31 and a secondary side isolation circuit 32 . The primary-side isolation circuit 31 is coupled to the AC-to-DC converter 2 and the primary-side controller 4 for receiving the second control signal S _C2 and the DC input voltage V _INDC provided by the primary-side controller 4 . The secondary-side isolation circuit 32 is coupled to the secondary-side rectifier controller 5 for isolating and converting the DC input voltage V _INDC .

The primary side isolation circuit 31 includes a bridge switching circuit 311 and a resonant circuit 312 . The bridge switching circuit 311 includes an upper switch _QH and a lower switch _QL . The first terminal of the upper switch Q _H is coupled to the AC-to-DC converter 2 . The first terminal of the lower switch _QL is coupled to the second terminal of the upper switch _QH and the resonant circuit 312. The primary side controller 4 provides the second control signal _SC2 to control the upper switch _QH and the lower switch _QL .

The secondary side isolation circuit 32 includes a bridge synchronous rectifier circuit 321 and a buck conversion circuit 322 . The bridge synchronous rectifier circuit 321 includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a first resonant inductor L1 and a second resonant inductor L2. The first terminal of the second switch Q2 is coupled to the second terminal of the first switch Q1. The first terminal of the third switch Q3 is coupled to the first terminal of the first switch Q1 and the buck conversion circuit 322 . The first terminal of the fourth switch Q4 is coupled to the second terminal of the third switch Q3. The first terminal of the first resonant inductor is coupled between the second terminal of the first switch Q1 and the first terminal of the second switch Q2. The first terminal of the second resonant inductor L2 is coupled to the second terminal of the first resonant inductor L1. The second terminal of the second resonant inductor L2 is coupled to the second terminal of the third switch Q3 and the first terminal of the fourth switch Q4. between. The secondary side rectification controller 5 provides the third control signal _SC3 to control the first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4.

The bridge synchronous rectifier circuit 321 further includes a first capacitor C1 and a second capacitor C2. The first terminal of the first capacitor C1 is coupled to the third switch Q3. The first terminal of the second capacitor C2 is coupled to the second terminal of the first capacitor C1, and the second terminal of the second capacitor C2 is coupled to the fourth switch Q4.

The buck conversion circuit 322 is used to convert the conversion voltage V _OON into the DC output voltage V _OUTDC . The buck conversion circuit 322 includes a fifth switch Q5, a sixth switch Q6, a diode D, an inductor L and a capacitor C. The first terminal of the fifth switch Q5 is coupled to the first terminal of the third switch Q3. The first terminal of the sixth switch Q6 is coupled between the second terminal of the first resonant inductor L1 and the first terminal of the second resonant inductor L2, and the second terminal of the sixth switch Q6 is coupled to the second terminal of the fifth switch Q5. . The cathode of the diode D is coupled to the second terminal of the fifth switch Q5 and the second terminal of the sixth switch Q6. The first terminal of the inductor L is coupled to the cathode of the diode D. The first terminal of the capacitor C is coupled to the second terminal of the inductor L, and the second terminal of the capacitor C is coupled to the anode of the diode D and the second terminal of the fourth switch Q4. In one embodiment, the sixth switch Q6 can be implemented with back-to-back semiconductor components, but this does not limit the present invention.

The primary side controller 4 is coupled to the AC-to-DC converter 2 and the DC-to-DC converter 3, provides the first control signal S _C1 to control the AC-to-DC converter 2 to convert and adjust the input voltage V _INRF to the DC input voltage V _INDC , and provides The second control signal S _C2 controls the DC-to-DC converter 3 .

The secondary side rectification controller 5 is coupled to the DC-to-DC converter 3 and provides the third control signal S _C3 to control the DC-to-DC converter 3 to convert the DC input voltage V _INDC to the conversion voltage V _CON based on the gain condition to supply power to the load 7 .

The secondary side feedback controller 6 is coupled to the primary side controller 4 and the secondary side rectification controller 5 . The secondary side feedback controller 6 receives the load power demand signal S _LP provided by the load 7 to control the operations of the primary side controller 4 and the secondary side rectification controller 5 . Specifically, the secondary side feedback controller 6 provides a feedback control signal including an AC and DC feedback control signal S _CAD and a DC and DC feedback control signal S _CDD to the primary side controller 4 , and provides the rectification control signal S _CSR to Secondary side rectification controller 5.

The primary side controller 4 controls the AC to DC converter 2 according to the AC and DC feedback control signal S _CAD , controls the DC to DC converter 3 according to the DC and DC feedback control signal S _CDD , and controls the secondary side according to the rectification control signal S _CSR . Rectifier controller 5 and adjust gain conditions.

When the bridge synchronous rectifier circuit 321 operates as a half-bridge, the conversion voltage V _CON is the first voltage, for example but not limited to 20 volts, and the third control signal S _C3 controls the first switch Q1 and the third switch Q3 to turn off , and controls the second switch Q2 and the fourth switch Q4 to switch and conduct each other, so the first resonant inductor L1 or the second resonant inductor L2 is excited. In this embodiment, when the second switch Q2 is turned on, a first magnetic excitation path is formed including the second switch Q2, the first resonant inductor L1 and the buck conversion circuit 322, so the first resonant inductor L1 is excited. When the fourth switch Q4 is turned on, a second magnetic excitation path is formed including the fourth switch Q4, the second resonant inductor L2 and the buck conversion circuit 322, so the second resonant inductor L2 is excited.

The symmetrical circuit operation is that when the conversion voltage V _CON is the first voltage, the third control signal S _C3 controls the second switch Q2 and the fourth switch Q4 to turn off, and controls the first switch Q1 and the third switch Q3 to switch on and off with each other, Therefore, the second resonant inductor L2 is excited. In this embodiment, when the first switch Q1 is turned on, a third magnetic excitation path is formed including the first switch Q1, the first resonant inductor L1 and the buck conversion circuit 322, so the first resonant inductor L1 is excited. When the third switch Q3 is turned on, a fourth magnetic excitation path is formed including the third switch Q3, the second resonant inductor L2 and the buck conversion circuit 322, so the second resonant inductor L2 is excited.

When the conversion voltage V _CON is less than the first voltage (that is, less than 20 volts), the fifth switch Q5 and the sixth switch Q6 turn on the buck conversion circuit 322 . Specifically, by controlling the duty cycle of the fifth switch Q5 or the duty cycle of the sixth switch Q6, the conversion voltage V _CON is stepped down into the DC output voltage V _OUTDC of different voltages to provide multiple sets of output voltages of different sizes.

When the bridge synchronous rectifier circuit 321 is in full-bridge operation, the conversion voltage V _CON is the second voltage, such as but not limited to 48 volts or 36 volts, and the third control signal S _C3 controls the first switch Q1 and the fourth switch Q4 is turned on and off at the same time, and controls the second switch Q2 and the third switch Q3 to be turned on and off at the same time, and controls the first switch Q1 and the second switch Q2 to switch on and off with each other, exciting the first resonant inductor L1 and the second resonant inductor L2. Specifically, when the first switch Q1 and the fourth switch Q4 are turned on at the same time, the first magnetic excitation path includes the first switch Q1, the first resonant inductor L1, the second resonant inductor L2, the fourth switch Q4 and the buck conversion circuit. 322, so the first resonant inductor L1 and the second resonant inductor L2 are excited at the same time. When the second switch Q2 and the third switch Q3 are turned on at the same time, the second magnetic excitation path includes the second switch Q2, the first resonant inductor L1, the second resonant inductor L2, the third switch Q3 and the buck conversion circuit 322. Therefore, The first resonant inductor L1 and the second resonant inductor L2 are excited at the same time.

When the conversion voltage V _CON is less than the second voltage (that is, less than 48 volts or 36 volts), the fifth switch Q5 and the sixth switch Q6 turn on the buck conversion circuit 322 . By controlling the duty cycle of the fifth switch Q5 or the duty cycle of the sixth switch Q6, the conversion voltage V _CON is stepped down into the DC output voltage V _OUTDC of different voltages to provide multiple sets of output voltages of different sizes.

The power converter proposed by the present invention can operate in a half-bridge or full-bridge circuit topology to flexibly provide multiple sets of output voltages of different sizes.

The above are only detailed descriptions and drawings of the preferred embodiments of the present invention. However, the characteristics of the present invention are not limited thereto and are not used to limit the present invention. The entire scope of the present invention should be determined by the following patent application scope. Subject to the present invention, all embodiments that are within the spirit of the patentable scope of the present invention and similar changes thereof shall be included in the scope of the present invention. Anyone familiar with the art can easily think of such changes or modifications in the field of the present invention. Modifications may be covered by the following patent scope of this case.

1: Primary side rectifier and filter circuit

2: AC to DC converter

3: DC to DC converter

4: Primary side controller

5: Secondary side rectification controller

6: Secondary side feedback controller

7:Load

V _IN :Input voltage

V _INRF : adjust the input voltage

V _INDC : DC input voltage

V _OUTDC : DC output voltage

S _C1 : first control signal

S _C2 : Second control signal

S _C3 : The third control signal

_SLP : Load power demand signal

S _CSR : Rectification control signal

S _CAD : AC and DC feedback control signal

S _CDD : DC feedback control signal

Claims (18)

A power converter includes: a primary side rectification and filtering circuit that receives an input voltage, and rectifies and filters the input voltage to output an adjusted input voltage; an AC to DC converter coupled to the primary side rectification and filtering circuit, and Receive the adjusted input voltage; a DC-to-DC converter is coupled to the AC-to-DC converter; a primary side controller is coupled to the AC-to-DC converter and the DC-to-DC converter to provide a first control signal control The AC-to-DC converter converts the adjusted input voltage into a DC input voltage and provides a second control signal to control the DC-to-DC converter; the primary side rectification controller is coupled to the DC-to-DC converter and provides a The third control signal controls the DC-to-DC converter to convert the DC input voltage into a conversion voltage based on a gain condition to power a load; and a primary-side feedback controller coupled to the primary-side controller and the secondary Side rectification controller, the secondary side feedback controller receives a load power supply demand signal provided by the load to control the operations of the primary side controller and the secondary side rectification controller. The power converter as claimed in claim 1, wherein the secondary side feedback controller provides a feedback control signal including an AC and DC feedback control signal and a DC feedback control signal to the primary side controller, and Provide a rectification control signal to the secondary-side rectification controller; wherein the primary-side controller controls the AC-to-DC converter according to the AC-DC feedback control signal, and controls the DC-to-DC conversion according to the DC-DC feedback control signal. controller, and controls the secondary side rectification controller and adjusts the gain condition according to the rectification control signal. The power converter as described in claim 1, wherein the DC-to-DC converter includes: a primary-side isolation circuit coupled to the AC-to-DC converter and the primary-side controller for receiving the second control signal and the DC input voltage; and a primary-side isolation circuit coupled to the secondary-side rectification control converter to isolate and convert the DC input voltage. The power converter of claim 3, wherein the primary side isolation circuit includes a bridge switching circuit and a resonant circuit; the secondary side isolation circuit includes a bridge synchronous rectification circuit and a buck conversion circuit. The power converter of claim 4, wherein the bridge switching circuit includes: an upper switch, a first end of the upper switch coupled to the AC to DC converter; and a lower switch, a first end of the lower switch One end is coupled to a second end of the upper switch and the resonant circuit; wherein the primary side controller provides the second control signal to control the upper switch and the lower switch. The power converter of claim 4, wherein the bridge synchronous rectification circuit includes: a first switch; a second switch, a first end of the second switch is coupled to a second end of the first switch ; A third switch, a first end of the third switch is coupled to a first end of the first switch and the buck conversion circuit; A fourth switch, a first end of the fourth switch is coupled a second terminal of the third switch; a first resonant inductor, a first terminal of the first resonant inductor coupled between the second terminal of the first switch and the first terminal of the second switch; and a second resonant inductor, a first end of the second resonant inductor is coupled to the second end of the first resonant inductor, and a second end of the second resonant inductor is coupled to the second end of the third switch. between the terminal and the first terminal of the fourth switch; The secondary side rectification controller provides the third control signal to control the first switch, the second switch, the third switch and the fourth switch. The power converter of claim 6, wherein the bridge synchronous rectifier circuit further includes: a first capacitor, a first end of the first capacitor is coupled to the third switch; and a second capacitor, the third switch A first terminal of the two capacitors is coupled to a second terminal of the first capacitor, and a second terminal of the second capacitor is coupled to the fourth switch. The power converter of claim 6, wherein the buck conversion circuit includes: a fifth switch, a first terminal of the fifth switch is coupled to the first terminal of the third switch; a sixth switch , a first end of the sixth switch is coupled between the second end of the first resonant inductor and the first end of the second resonant inductor, and a second end of the sixth switch is coupled to the fifth a second end of the switch; a diode, a cathode of the diode is coupled to the second end of the fifth switch and the second end of the sixth switch; an inductor, a first end of the inductor A terminal is coupled to the cathode of the diode; and a capacitor, a first terminal of the capacitor is coupled to a second terminal of the inductor, and a second terminal of the capacitor is coupled to an anode of the diode and the A second terminal of the fourth switch. The power converter of claim 8, wherein when the conversion voltage is a first voltage, the first switch and the third switch are turned off, and the second switch and the fourth switch are switched on and excited. the first resonant inductor or the second resonant inductor. The power converter of claim 9, wherein when the second switch is turned on, a first magnetic excitation path is formed including the second switch, the first resonant inductor and the buck conversion circuit, and the The first resonant inductor is excited; when the fourth switch is turned on, a second magnetic excitation path is formed including the fourth switch, the second resonant inductor and the buck conversion circuit, and the second resonant inductor is excited. The power converter as claimed in claim 8, wherein when the conversion voltage is a first voltage, the second switch and the fourth switch are turned off, and the first switch and the third switch are switched on and excited. the first resonant inductor or the second resonant inductor. The power converter of claim 11, wherein when the first switch is turned on, a third magnetic excitation path is formed including the first switch, the first resonant inductor and the buck conversion circuit, and the first resonant The inductor is excited; when the third switch is turned on, a fourth magnetic excitation path is formed including the third switch, the second resonant inductor and the buck conversion circuit, and the second resonant inductor is excited. The power converter of claim 8, wherein when the conversion voltage is a second voltage, the first switch and the fourth switch are turned on and off at the same time, and the second switch and the third switch are turned on and off at the same time. is turned off, and the first switch and the second switch are switched on and off to excite the first resonant inductor and the second resonant inductor. The power converter of claim 13, wherein when the first switch and the fourth switch are turned on at the same time, a first magnetic excitation path is formed including the first switch, the first resonant inductor, and the second resonant inductor. , the fourth switch and the buck conversion circuit; when the second switch and the third switch are turned on at the same time, a second magnetic excitation path is formed including the second switch, the first resonant inductor, the second resonant The inductor, the third switch and the buck conversion circuit. The power converter of claim 9, wherein when the conversion voltage is less than the first voltage, the fifth switch and the sixth switch conduct the buck conversion circuit. The power converter of claim 13, wherein when the conversion voltage is less than the second voltage, the fifth switch and the sixth switch conduct the buck conversion circuit. The power converter of claim 8, wherein the step-down conversion circuit is used to convert the conversion voltage into a DC output voltage. The power converter of claim 17, wherein the conversion voltage is stepped down into the DC output voltages of different voltages by controlling a duty cycle of the fifth switch or a duty cycle of the sixth switch.

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