Bipolar output resonant DC-DC converter

Abstract

The invention provides a bipolar output resonant DC-DC converter, and belongs to the technical field of power electronics. The output end of the control circuit is respectively connected with the control ends of the input half bridge and the output half bridge, the input end of the input half bridge is connected with an input signal, the first output end of the input half bridge is connected with one end of the resonance network, and the second output end of the input half bridge is grounded; the other end of the resonance network is connected with the input end of the output half bridge, the first output end and the second output end of the output half bridge are both connected with an external load, and the two output ends of the output half bridge are used for outputting positive polarity voltage and negative polarity voltage respectively; the resonant network is used for energy transmission between the input half-bridge and the output half-bridge, and the input half-bridge and the output half-bridge are circularly switched on or switched off within a preset work period under the action of a control signal output by the control circuit, so that bidirectional energy transmission of the resonant network is realized. According to the invention, the reliability, the conversion efficiency and the power density of the bipolar output power supply can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, in particular to a bipolar output resonant DC-DC converter. BACKGROUND

[0002] Power management integrated circuits (PMICs) are widely used in consumer electronics, industrial control, automotive electronics, aerospace, and energy exploration as the core power supply units of various electronic systems. With the widespread application of high-performance sensors, analog-to-digital converters (ADCs), and precision analog front-end circuits in complex environments, higher requirements are placed on the functionality and reliability of power supplies, especially in extreme conditions such as high temperature and high vibration. The traditional power supply architecture faces severe challenges. At the same time, to meet the needs of precision analog front-end circuits for wide dynamic range and low-noise power supply, power management integrated circuits also need to provide positive and negative voltage outputs to achieve unbiased processing of alternating signals and common-mode noise suppression.

[0003] Currently, bipolar output power supplies are mainly implemented in two ways. The first way is to use two independent DC-DC converters to generate positive and negative voltage outputs, such as using a buck converter to provide positive voltage output and a flyback converter or a buck-boost converter to provide negative voltage output. The second way is to use a single-inductor bipolar output (SIBO) converter structure to simultaneously achieve positive and negative voltage outputs.

[0004] However, when implementing a bipolar output power supply using the above two methods, the first method requires two separate power inductors, which results in a large size, high cost, and low power density of the power management integrated circuit. The second method mainly focuses on step-up in low-voltage power supply scenarios, which results in poor step-down output capability and low conversion efficiency in high-voltage scenarios, and has the problem of two-way cross-regulation / coupling. In addition, as the system operating frequency increases in high-frequency operating scenarios, the hard switching loss of the power stage will increase significantly, which will further deteriorate the conversion efficiency. Furthermore, due to the limitations of system operating frequency and output ripple, most existing designs still require the use of large inductors, limiting further improvement in power density. Therefore, the related art has the problems of poor reliability, low conversion efficiency, and limited power density. SUMMARY

[0005] The present application aims to provide a bipolar output resonant DC-DC converter that can improve the reliability, conversion efficiency, and power density of bipolar output power supplies.

[0006] The embodiments of this application are implemented as follows: A first aspect of this application provides a bipolar output resonant DC-DC converter, which includes: an input half-bridge, a resonant network, an output half-bridge, and a control circuit. The output terminal of the control circuit is connected to the control terminal of the input half-bridge and the control terminal of the output half-bridge respectively. The input terminal of the input half-bridge is used to receive the input signal. The first output terminal of the input half-bridge is connected to one end of the resonant network, and the second output terminal of the input half-bridge is grounded. The other end of the resonant network is connected to the input of the output half-bridge. The first and second outputs of the output half-bridge are both connected to an external load. The first output of the output half-bridge is used to output a positive voltage, and the second output of the output half-bridge is used to output a negative voltage. The resonant network is used for energy transfer between the input half-bridge and the output half-bridge. The input half-bridge and the output half-bridge are cyclically turned on or off within a preset working cycle under the control signal output by the control circuit, so as to realize the bidirectional energy transfer of the resonant network.

[0007] As one possible implementation, the resonant network includes: a first capacitor and an inductor; the input half-bridge includes: a first switch and a second switch; the output half-bridge includes: a third switch and a fourth switch; One end of the first capacitor is connected to the output terminal of the first switch and the input terminal of the second switch, and the other end of the first capacitor is connected to one end of the inductor, and the other end of the inductor is connected to the input terminal of the third switch and the input terminal of the fourth switch. The input terminal of the first switch is used to receive the input signal, and the output terminal of the first switch is also connected to the input terminal of the second switch, and the output terminal of the second switch is grounded; the input terminal of the third switch is also connected to the input terminal of the fourth switch, and the output terminals of the third switch and the fourth switch are both connected to an external load. The control terminals of the first switch, the second switch, the third switch, and the fourth switch are all connected to the output terminal of the control circuit. The voltage node connecting the output terminal of the first switch and the input terminal of the second switch serves as the input switch voltage node, and the voltage node connecting the input terminal of the third switch and the input terminal of the fourth switch serves as the output switch voltage node. The output terminal of the third switch is used to output a positive voltage, and the output terminal of the fourth switch is used to output a negative voltage.

[0008] As one possible implementation, the control circuit described above includes: a zero-crossing detection module; The first input end of the zero-crossing detection module is connected with the other end of the first capacitor and one end of the inductor, the second input end of the zero-crossing detection module is grounded, the third input end of the zero-crossing detection module is connected with the input switch voltage node, the first output end of the zero-crossing detection module is connected with the control end of the third switch, and the second output end of the zero-crossing detection module is connected with the control end of the fourth switch.

[0009] As a possible implementation manner, the zero-crossing detection module comprises an inductor current detection circuit, a zero-crossing detection circuit, a first SR flip-flop and a first non-overlapping clock generator. The sampling end of the inductor current detection circuit is connected with the other end of the first capacitor and one end of the inductor, the output end of the inductor current detection circuit is connected with the first input end of the zero-crossing detection circuit, the second input end of the zero-crossing detection circuit is grounded, the third input end of the zero-crossing detection circuit is connected with the input switch voltage node, the first output end of the zero-crossing detection circuit is connected with the set end of the first SR flip-flop, the second output end of the zero-crossing detection circuit is connected with the reset end of the first SR flip-flop, the data output end of the first SR flip-flop is connected with the input end of the first non-overlapping clock generator, the first output end of the first non-overlapping clock generator is connected with the control end of the third switch, and the second output end of the first non-overlapping clock generator is connected with the control end of the fourth switch.

[0010] As a possible implementation manner, the control circuit further comprises a peak current control module and an adaptive zero-voltage turn-on adjustment module. The first input end of the adaptive zero-voltage turn-on adjustment module is used for inputting an input signal, the second input end of the adaptive zero-voltage turn-on adjustment module is connected with the input switch voltage node, the third input end of the adaptive zero-voltage turn-on adjustment module is used for inputting a power supply voltage, the fourth input end of the adaptive zero-voltage turn-on adjustment module is connected with the first output end of the zero-crossing detection circuit, and the output end of the adaptive zero-voltage turn-on adjustment module is connected with the control end of the second switch. The first input end of the peak current control module is connected with the output end of the third switch, the second input end of the peak current control module is used for inputting a preset reference voltage, the third input end of the peak current control module is connected with the output end of the inductor current detection circuit, the fourth input end of the peak current control module is connected with the first output end of the zero-crossing detection circuit, the first output end of the peak current control module is connected with the control end of the first switch, and the second output end of the peak current control module is connected with the fifth input end of the adaptive zero-voltage turn-on adjustment module. The adaptive zero-voltage turn-on adjustment module is used for controlling the turn-off time of the second switch, so as to control the zero-voltage turn-on state of the first switch.

[0011] As a possible implementation manner, the adaptive zero-voltage turn-on adjustment module comprises a first comparator, a second comparator, a reference voltage generation circuit, a ramp signal generation circuit and a second SR flip-flop; The negative input end of the first comparator is used for accessing the input signal, the positive input end of the first comparator is connected with the input switch voltage node, the output end of the first comparator is connected with the first input end of the reference voltage generation circuit, the second input end of the reference voltage generation circuit is used for accessing the power supply voltage, the third input end of the reference voltage generation circuit is connected with the first output end of the zero-crossing detection circuit, and the output end of the reference voltage generation circuit is connected with the negative input end of the second comparator; The data output end of the second SR flip-flop is connected with the control end of the second switch, the inverted output end of the second SR flip-flop is connected with the control end of the ramp signal generation circuit, the input end of the ramp signal generation circuit is used for accessing the power supply voltage, the output end of the ramp signal generation circuit is connected with the positive input end of the second comparator, the output end of the second comparator is connected with the reset end of the second SR flip-flop, and the set end of the second SR flip-flop is connected with the second output end of the peak current control module.

[0012] As a possible implementation manner, the reference voltage generation circuit comprises a first D flip-flop, a second D flip-flop, a NAND gate, a first current source, a second current source, a second capacitor, a fifth switch and a sixth switch. The clock input end of the first D flip-flop is connected with the output end of the first comparator, the data input end of the first D flip-flop and the data input end of the second D flip-flop are both used for accessing the power supply voltage, the clock input end of the second D flip-flop is connected with the first output end of the zero-crossing detection circuit, the data output end of the first D flip-flop is connected with the control end of the fifth switch and the first input end of the NAND gate respectively, the data output end of the second D flip-flop is connected with the control end of the sixth switch and the second input end of the NAND gate respectively, and the output end of the NAND gate is connected with the reset end of the first D flip-flop and the reset end of the second D flip-flop respectively. The input end of the first current source is used for accessing the power supply voltage, the output end of the first current source is connected with the input end of the fifth switch, the output end of the fifth switch is connected with one end of the second capacitor, the input end of the sixth switch and the negative input end of the second comparator respectively, the output end of the sixth switch is connected with the input end of the second current source, and the output end of the second current source and the other end of the second capacitor are both grounded.

[0013] As a possible implementation manner, the ramp signal generation circuit comprises a P-type metal oxide semiconductor transistor, an N-type metal oxide semiconductor transistor, a third current source and a third capacitor. The gate of the P-type metal oxide semiconductor transistor and the gate of the N-type metal oxide semiconductor transistor are connected with the inverting output terminal of the second SR flip-flop, the source of the P-type metal oxide semiconductor transistor is connected with the output terminal of the third current source, the input terminal of the third current source is used for connecting with the power supply voltage, the drain of the P-type metal oxide semiconductor transistor and the drain of the N-type metal oxide semiconductor transistor are respectively connected with the positive input terminal of the second comparator and one end of the third capacitor; The source of the N-type metal oxide semiconductor transistor and the other end of the third capacitor are grounded.

[0014] As a possible implementation manner, the peak current control module comprises: a voltage dividing network, a compensation network, a current-voltage converter, a third comparator, a third SR flip-flop and a second non-overlapping clock generator. The input terminal of the voltage dividing network is connected with the output terminal of the third switch, the first output terminal of the voltage dividing network is connected with the first input terminal of the compensation network, and the second output terminal of the voltage dividing network is grounded. The second input terminal of the compensation network is used for connecting with a preset reference voltage, the output terminal of the compensation network is connected with the negative input terminal of the third comparator, the positive input terminal of the third comparator is connected with the output terminal of the current-voltage converter, and the input terminal of the current-voltage converter is connected with the output terminal of the inductor current detection circuit. The reset terminal of the third SR flip-flop is connected with the output terminal of the third comparator, the set terminal of the third SR flip-flop is connected with the first output terminal of the zero-crossing detection circuit, the data output terminal of the third SR flip-flop is connected with the input terminal of the second non-overlapping clock generator, the first output terminal of the second non-overlapping clock generator is connected with the control terminal of the first switch, and the second output terminal of the second non-overlapping clock generator is connected with the fifth input terminal of the adaptive zero-voltage opening adjustment module.

[0015] As a possible implementation manner, the voltage dividing network comprises: a first resistor and a second resistor, and the compensation network comprises: an error amplifier, a fourth capacitor, a fifth capacitor and a third resistor. One end of the first resistor is connected with the output terminal of the third switch, the other end of the first resistor is respectively connected with one end of the second resistor and the negative input terminal of the error amplifier, the positive input terminal of the error amplifier is used for connecting with a preset reference voltage, and the other end of the second resistor is grounded. The negative input terminal of the error amplifier is also connected with one end of the third resistor and one end of the fourth capacitor, the other end of the third resistor is connected with one end of the fifth capacitor, the other end of the fourth capacitor and the other end of the fifth capacitor are both connected with the output terminal of the error amplifier, and the output terminal of the error amplifier is also connected with the negative output terminal of the third comparator.

[0016] A second aspect of this application provides a bipolar output power supply in which a bipolar output resonant DC-DC converter as described in the first aspect is deployed.

[0017] The beneficial effects of the embodiments of this application include: This application provides a bipolar output resonant DC-DC converter comprising: an input half-bridge, a resonant network, an output half-bridge, and a control circuit. The input terminal of the input half-bridge is used to receive an input signal. The first output terminal of the input half-bridge is connected to one end of the resonant network, and the second output terminal of the input half-bridge is grounded. The other end of the resonant network is connected to the output terminal of the output half-bridge. Both the first and second output terminals of the resonant network are connected to an external load. The first output terminal of the output half-bridge outputs a positive voltage, and the second output terminal outputs a negative voltage. The control terminals of both the input and output half-bridges are connected to the control circuit. An LC resonant network is positioned between the input and output half-bridges, providing a bidirectional energy transfer bridge. By introducing a small inductor to eliminate large pulse currents from the capacitor, the LC resonant network achieves high energy utilization and expands load capacity while maintaining high conversion efficiency and power density. The control circuit switches the switching sequence of the power switches in the input and output half-bridges within a preset operating cycle to adjust the operating mode of the resonant network, enabling the entire system to have continuous output voltage regulation capabilities. Furthermore, the power switches in the input and output half-bridges cycle on and off within a preset duty cycle, enabling bidirectional energy transfer in the resonant network. This optimizes the operating mode of the power switches in the DC-DC converter, thereby reducing switching losses and improving conversion efficiency. Ultimately, this improves the reliability, conversion efficiency, and power density of the bipolar output power supply. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a first bipolar output resonant DC-DC converter provided in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of a second bipolar output resonant DC-DC converter provided in the embodiments of this application; Figure 3A schematic diagram of the operating mode of the first-stage bipolar output resonant DC-DC converter provided in the embodiments of this application; Figure 4 A schematic diagram of the operating mode of the second-stage bipolar output resonant DC-DC converter provided in the embodiments of this application; Figure 5 A schematic diagram of the operating mode of the third-stage bipolar output resonant DC-DC converter provided in the embodiments of this application; Figure 6 A schematic diagram of the operating mode of the fourth-stage bipolar output resonant DC-DC converter provided in the embodiments of this application; Figure 7 A waveform diagram of a bipolar output resonant DC-DC converter provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of a third bipolar output resonant DC-DC converter provided in the embodiments of this application; Figure 9 A freewheeling schematic diagram illustrating the state switching of a first type of bipolar output resonant DC-DC converter provided in this application embodiment; Figure 10 A freewheeling schematic diagram illustrating the state switching of a second type of bipolar output resonant DC-DC converter provided in an embodiment of this application; Figure 11 A freewheeling schematic diagram illustrating the state switching of a third type of bipolar output resonant DC-DC converter provided in this application embodiment; Figure 12 The waveform diagram of a bipolar output resonant DC-DC converter provided in this application embodiment within a preset working cycle; Figure 13 A waveform diagram of zero-voltage start-up of a first switch provided in an embodiment of this application; Figure 14 A freewheeling diagram illustrating the state switching of a fourth type of bipolar output resonant DC-DC converter provided in this application embodiment; Figure 15 This is a schematic diagram of a bipolar output power supply provided in an embodiment of this application.

[0020] Reference numerals: 10: Bipolar output resonant DC-DC converter; 101: Input half-bridge; 1011: First switch; 1012: Second switch; 102: Resonant network; 1021: First capacitor; 1022: Inductor; 103: Output half-bridge; 1031: Third switch; 1032: Fourth switch; 104: Control circuit; 1041: Zero-crossing detection module; 411: Zero-crossing detection circuit; 412: First SR flip-flop; 413: First non-overlapping... Clock generator; 414: Inductor current detection circuit; 1042: Peak current control module; 421: Voltage divider network; 4211: First resistor; 4212: Second resistor; 422: Compensation network; 4221: Error amplifier; 4222: Fourth capacitor; 4223: Fifth capacitor; 4224: Third resistor; 423: Current-to-voltage converter; 424: Third comparator; 425: Third SR flip-flop; 426: Second non-overlapping clock generator; 1 043: Adaptive zero-voltage turn-on adjustment module; 431: First comparator; 432: Second comparator; 433: Reference voltage generation circuit; 4331: First D flip-flop; 4332: Second D flip-flop; 4333: NAND gate; 4334: First current source; 4335: Second current source; 4336: Second capacitor; 4337: Fifth switch; 4338: Sixth switch; 434: Ramp signal generation circuit; 4341: P-type metal-oxide-semiconductor transistor; 4342: N-type metal-oxide-semiconductor transistor; 4343: Third current source; 4344: Third capacitor; 435: Second SR flip-flop; 20: Bipolar output power supply; 170: Level shifting circuit and gate drive buffer for the first switch; 171: Level shifting circuit and gate drive buffer for the third switch; 180: Level shifting circuit and gate drive buffer for the second switch; 190: Level shifting circuit and gate drive buffer for the fourth switch. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this application, it should be noted that the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Power management chips, as the power supply hub for all electronic products and devices, are essential electronic components for building efficient, stable, and reliable power systems. However, most current power management chips are researched and designed at room temperature, which results in poor adaptability to high-temperature environments, making them unsuitable for harsh high-temperature operating environments such as deep well drilling and aerospace systems.

[0026] In addition, compared to power electronic converters operating at room temperature, the performance of power electronic converters will significantly decrease when they enter a high-temperature operating environment, such as reduced efficiency, weakened noise immunity, and decreased system reliability.

[0027] For example, in oil and gas applications, electronic equipment typically operates in downhole environments ranging from 150°C to 175°C, and with deeper drilling, downhole temperatures can even reach 200°C. Furthermore, the drill bit vibrates at high frequencies during drilling, affecting the detection accuracy of exploration sensors, analog-to-digital converters, and numerous other analog front-end components. Especially in high-temperature environments, this vibration interference can lead to signal distortion, increased noise, and measurement errors during data acquisition, further deteriorating the reliability and accuracy of the entire system. Therefore, there is an urgent need to develop and design a power management chip that can operate efficiently and stably in high-temperature environments to improve the overall performance of the power system.

[0028] In addition, to improve the detection accuracy of precision devices in the analog front end, the power management chip also needs to have the ability to output positive and negative voltage rails in both directions, thereby providing a wider dynamic range and power margin for the signal chain, thus suppressing the noise of the power system and ensuring that the power system can operate efficiently and reliably under harsh conditions.

[0029] Currently, bipolar output power supplies are commonly implemented in two ways. The first is to use two independent DC-DC converters to generate positive and negative outputs respectively, such as using a buck converter to provide the positive output and a flyback or buck-boost converter to provide the negative output. The second is a single-inductor bipolar output converter structure, such as using a single inductor to achieve both positive and negative voltage outputs simultaneously. However, the first method requires two separate power inductors, which leads to a large power management chip, high cost, low power density, and difficulty in achieving power matching and cross-regulation between the two outputs. The second method is mainly for boosting in low-voltage power supply scenarios, resulting in poor buck output capability and low conversion efficiency in high-voltage scenarios, and also suffers from cross-regulation / coupling issues between the two outputs. In addition, as the system operating frequency increases in high-frequency scenarios, the hard switching losses of the power stage will increase significantly, leading to further deterioration in conversion efficiency. Furthermore, due to limitations in system operating frequency and output ripple, most existing designs still require the use of large inductors, limiting further increases in power density. Therefore, the solutions disclosed in the relevant technologies suffer from poor reliability, low conversion efficiency, and limited power density.

[0030] To address this, this application provides a bipolar output resonant DC-DC converter, comprising an input half-bridge, a resonant network, an output half-bridge, and a control circuit. The control terminals of both the input and output half-bridges are connected to the output terminal of the control circuit. An input signal is received at the input terminal of the input half-bridge, one output terminal of the input half-bridge is connected to one end of the resonant network, and the other output terminal is grounded. The input terminal of the output half-bridge is connected to the other end of the resonant network, one output terminal of the output half-bridge outputs a positive voltage, and the other output terminal outputs a negative voltage. This application uses the control circuit to control the power switches in the input and output half-bridges to cyclically turn on and off within a preset operating cycle, thereby achieving bidirectional energy transfer through the resonant network. This optimizes the operating mode of the power switches in the DC-DC converter, reducing switching losses and improving conversion efficiency. Furthermore, by optimizing the operating mode of the power switches, this application addresses the problem of the operating frequency being limited by switching losses in existing circuit architectures, thereby increasing power density. Thus, it achieves the effects of improving the reliability, conversion efficiency, and power density of the bipolar output power supply.

[0031] The following description, in conjunction with the accompanying drawings, provides a detailed explanation of the bipolar output resonant DC-DC converter and bipolar output power supply provided in the embodiments of this application.

[0032] Figure 1 See the schematic diagram of the bipolar output resonant DC-DC converter provided in this application. Figure 1This application provides a bipolar output resonant DC-DC converter 10, which includes an input half-bridge 101, a resonant network 102, an output half-bridge 103, and a control circuit 104.

[0033] The output terminal of the control circuit 104 is connected to the control terminal of the input half-bridge 101 and the control terminal of the output half-bridge 103 respectively. The input terminal of the input half-bridge 101 is used to receive the input signal. The first output terminal of the input half-bridge 101 is connected to one end of the resonant network 102, and the second output terminal of the input half-bridge 101 is grounded.

[0034] Optionally, both the input half-bridge 101 and the output half-bridge 103 are half-bridge structures composed of power switches. The power switches in the input half-bridge 101 and the output half-bridge 103 are turned on or off under the control of the control circuit 104 to convert the input signal into the signal required by the user. The input signal can specifically be a DC signal, such as a DC voltage, and this application does not specifically limit it.

[0035] Optionally, the resonant network 102 is used to provide an energy transmission path for the input half-bridge 101 and the output half-bridge 103. The input half-bridge 101 converts the incoming DC signal into an AC signal based on the switching of the internal power switch, and transmits it to the output half-bridge 103 via the resonant network 102. The output half-bridge 103 converts the received signal into a positive or negative output voltage.

[0036] The control circuit 104 may include various types of control circuits, such as feedback regulation circuits and zero-voltage turn-on circuits. The output terminal of the control circuit 104 includes the output terminals of all its internal sub-control circuits. The input half-bridge 101 includes at least two power switches. Each output terminal of the input half-bridge 101 corresponds to the output terminal of a power switch. The input terminal of the input half-bridge 101 is the input terminal of the power switch in the main power circuit of the input half-bridge 101. The output half-bridge 103 includes at least two power switches. The input terminal of the output half-bridge 103 refers to the input terminal of all power switches in the output half-bridge 103. Each output terminal of the output half-bridge 103 corresponds to the output terminal of a power switch.

[0037] Optionally, the resonant network 102 is specifically an LC resonant network formed by a capacitor and an inductor connected in series. The resonant network 102 is mainly used for signal transmission and filtering. The resonant network 102 can provide a bidirectional energy output path for the input half-bridge 101 and the output half-bridge 103.

[0038] The other end of the resonant network 102 is connected to the input terminal of the output half-bridge 103. The first output terminal and the second output terminal of the output half-bridge 103 are both connected to an external load. The first output terminal of the output half-bridge 103 is used to output a positive voltage, and the second output terminal of the output half-bridge 103 is used to output a negative voltage.

[0039] Optionally, the positive or negative voltage output by the output half-bridge 103 is the final supply voltage provided by the bipolar output resonant DC-DC converter 10 to the external load.

[0040] Specifically, one end of the resonant network 102 refers to the end other than the end where the capacitor and inductor are connected in the resonant network 102, and the other end of the resonant network 102 refers to the end other than the end where the inductor and capacitor are connected in the resonant network 102. That is, one end of the resonant network 102 is the end where the capacitor is connected to the first output terminal of the input half-bridge 101, and the other end of the resonant network 102 is the end where the inductor is connected to the input terminal of the output half-bridge 103.

[0041] The resonant network 102 is used to transfer energy between the input half-bridge 101 and the output half-bridge 103. The input half-bridge 101 and the output half-bridge 103 are cyclically turned on or off within a preset working cycle under the control signal output by the control circuit 104, so as to realize the bidirectional energy transfer of the resonant network 102.

[0042] Optionally, the resonant network 102 is composed of components such as non-polar capacitors and inductors. One end of the resonant network 102 is connected to the first output terminal of the input half-bridge 101, and the other end of the resonant network 102 is connected to the input terminal of the output half-bridge 103, thereby realizing bidirectional energy transfer between the input half-bridge 101 and the output half-bridge 103.

[0043] Optionally, the preset working cycle is the cyclic working cycle of the bipolar output resonant DC-DC converter 10 preset by the user. The bipolar output resonant DC-DC converter 10 has multiple working modes in the preset working cycle, and the bipolar output resonant DC-DC converter 10 switches cyclically according to these working modes within the preset working cycle.

[0044] In this embodiment, the bipolar output resonant DC-DC converter includes an input half-bridge, a resonant network, an output half-bridge, and a control circuit. The input terminal of the input half-bridge is used to receive the input signal. The first output terminal of the input half-bridge is connected to one end of the resonant network, and the second output terminal of the input half-bridge is grounded. The other end of the resonant network is connected to the output terminal of the output half-bridge. Both the first and second output terminals of the resonant network are connected to an external load. The first output terminal of the output half-bridge is used to output a positive voltage, and the second output terminal of the output half-bridge is used to output a negative voltage. The control terminals of both the input and output half-bridges are connected to the control circuit. An LC resonant network is positioned between the input and output half-bridges, providing a bidirectional energy transfer bridge. By introducing a small inductor, the LC resonant network eliminates the large pulse current of the capacitor, achieving high energy utilization and expanding load capacity while maintaining high conversion efficiency and power density. The control circuit switches the switching sequence of the power switches in the input and output half-bridges within a preset operating cycle to adjust the operating mode of the resonant network, enabling the entire system to have continuous output voltage regulation capabilities. Furthermore, the power switches in the input and output half-bridges cycle on and off within a preset duty cycle, enabling bidirectional energy transfer in the resonant network. This optimizes the operating mode of the power switches in the DC-DC converter, thereby reducing switching losses and improving conversion efficiency. Ultimately, this improves the reliability, conversion efficiency, and power density of the bipolar output power supply.

[0045] In one alternative implementation, see [link to implementation details]. Figure 2 The resonant network 102 of the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a first capacitor 1021 and an inductor 1022; the input half-bridge 101 includes: a first switch 1011 and a second switch 1012; and the output half-bridge 103 includes: a third switch 1031 and a fourth switch 1032.

[0046] Optionally, the input half-bridge 101 and output half-bridge 103 of the bipolar output resonant DC-DC converter 10 are each composed of two switches. The input half-bridge 101 is composed of a first switch 1011 and a second switch 1012, and the output half-bridge 103 is composed of a third switch 1031 and a fourth switch 1032. All four switches—the first switch 1011, the second switch 1012, the third switch 1031, and the fourth switch 1032—are implemented using high-voltage power switches.

[0047] Optionally, the resonant network 102 is formed by a first capacitor 1021 and an inductor 1022 connected in series. The first capacitor 1021 is a small-value resonant capacitor, and the inductor 1022 is a resonant inductor. That is, the resonant network 102 is an LC resonant network composed of a resonant capacitor and a resonant inductor. The resonant network 102 is disposed between the input half-bridge 101 and the output half-bridge 103, serving as the energy transmission bridge and intermediate storage medium of the bipolar output resonant DC-DC converter 10.

[0048] One end of the first capacitor 1021 is connected to the output terminal of the first switch 1011 and the input terminal of the second switch 1012. The other end of the first capacitor 1021 is connected to one end of the inductor 1022. The other end of the inductor 1022 is connected to the input terminal of the third switch 1031 and the input terminal of the fourth switch 1032. The input terminal of the first switch 1011 is used to receive the input signal, and the output terminal of the first switch 1011 is also connected to the input terminal of the second switch 1012, and the output terminal of the second switch 1012 is grounded; the input terminal of the third switch 1031 is also connected to the input terminal of the fourth switch 1032, and the output terminals of the third switch 1031 and the fourth switch 1032 are both connected to the external load. The control terminals of the first switch 1011, the second switch 1012, the third switch 1031, and the fourth switch 1032 are all connected to the output terminal of the control circuit 104. The voltage node connecting the output terminal of the first switch 1011 and the input terminal of the second switch 1012 serves as the input switch voltage node. The voltage node connecting the input terminal of the third switch 1031 and the input terminal of the fourth switch 1032 serves as the output switch voltage node. The output terminal of the third switch 1031 is used to output a positive voltage, and the output terminal of the fourth switch 1032 is used to output a negative voltage.

[0049] It should be noted that the bipolar output resonant DC-DC converter 10 provided in this application embodiment fully utilizes the structure of an LC resonant network. Compared with traditional inductor-type converters, by introducing a smaller resonant capacitor (i.e., the first capacitor 1021), the utilization rate of the inductor 1022 can be improved and the size of the inductor can be reduced. In addition, due to the resonant operating mode of the LC resonant network, the inductor current of the inductor 1022 can transfer energy through both positive and negative polarities. This not only facilitates the output of a negative polarity voltage by the bipolar output resonant DC-DC converter 10, but also lays the foundation for zero-voltage switching of all power switches in the bipolar output resonant DC-DC converter 10.

[0050] Furthermore, compared to traditional single-inductor bipolar output converters, this application employs fewer power switches, smaller inductors, and smaller capacitors (such as the first capacitor 1021 with a capacitance of approximately 2nF), which can significantly improve the power density of the converter.

[0051] Furthermore, since the bipolar output resonant DC-DC converter 10 can achieve zero-voltage turn-on of all switches, the hard switching losses of the power switching transistors are greatly reduced, enabling power systems using this bipolar output resonant DC-DC converter 10 to operate efficiently at higher operating frequencies.

[0052] It should also be noted that the operating frequency of the bipolar output resonant DC-DC converter 10 provided in this application embodiment is mainly determined by the resonant frequency of the resonant network 102. The higher the operating frequency of the bipolar output resonant DC-DC converter 10, the smaller the specifications of the resonant capacitor and resonant inductor used in the bipolar output resonant DC-DC converter 10. This not only reduces the size of the passive components in the bipolar output resonant DC-DC converter 10, but also greatly improves the power density of the system.

[0053] In the following figures, Cr indicates the first capacitor 1021, L indicates the inductor 1022, S1 indicates the first switch 1011, S2 indicates the second switch 1012, S3 indicates the third switch 1031, S4 indicates the fourth switch 1032, Vin indicates the input signal, Vop indicates the positive output voltage, and Von indicates the negative output voltage.

[0054] Figure 3 For a schematic diagram of the operating mode of the first-stage bipolar output resonant DC-DC converter provided in this application, please refer to [reference needed]. Figure 3 In the first stage, the control circuit controls the first switch S1 and the third switch S3 to turn on, and controls the second switch S2 and the fourth switch S4 to turn off. The input signal Vin simultaneously charges the positive output terminal Vop and the resonant network LC. All current flows through the inductor L. The positive output terminal Vop and the resonant capacitor Cr receive the same amount of charge Q1. The entire bipolar output resonant DC-DC converter 10 adopts the peak current control mode. When the inductor current of the inductor L reaches the threshold value set by the error amplifier (this threshold value is generated by comparing the voltage divider signal Vfbp of the positive output terminal Vop with the preset reference voltage Vrefp through the error amplifier, and then adjusting the output voltage threshold through the type II compensator), at this time, see Figure 4The system controls the first switch S1 to turn off, the second switch S2 to turn on, the third switch S3 to remain on, and the fourth switch S4 to remain off. The bipolar output resonant DC-DC converter 10 enters its second stage. The voltage difference across the resonant network 102 changes from Vin-Vop to -Vop, and the inductor L begins to release energy. The inductor current of inductor L gradually decreases, but the current direction remains unchanged (the current direction is still positive from left to right). During this process, the positive output terminal Vop and the resonant capacitor Cr continue to acquire charge Q2. When the zero-crossing detection circuit detects that the inductor current of inductor L has decreased to zero, the third switch S3 is turned off, and the fourth switch S4 is turned on, completing the second stage of the bipolar output resonant DC-DC converter 10.

[0055] During the entire positive half-cycle of the inductor current (i.e., the first stage of charging and the second stage of releasing energy), the inductor L does not accumulate energy, but only plays the role of transmitting charge and energy, so that the positive output terminal Vop and the resonant capacitor Cr obtain the same amount of charge Q1+Q2.

[0056] Figure 5 For a schematic diagram of the operating mode of the third-stage bipolar output resonant DC-DC converter provided in this application, please refer to [reference needed]. Figure 5 In the third stage, the bipolar output resonant DC-DC converter 10 enters the reverse energy transfer stage. Due to the periodic change in the direction of the resonant current in the resonant network 102, the resonant current of the resonant network 102 is now negative. The bipolar output resonant DC-DC converter 10 draws charge Q3 from the negative output terminal Von. At this time, only the inductor L discharges, and the amount of charge released by the capacitor Cr is equal to the amount of charge released by the negative output terminal Von. According to the law of conservation of charge, Q1 + Q2 = Q3, that is, Qop = |Qon|. Furthermore, before the bipolar output resonant DC-DC converter 10 enters the third stage, there is no energy stored in the inductor L; all energy is stored in the resonant capacitor Cr. After one complete negative half-cycle of resonant operation, all the energy in the resonant network 102 is released to the negative output terminal Von. After the power stage completes one large cycle, it returns to the first stage operating mode.

[0057] Optionally, according to the principles of energy conservation and charge conservation, the average voltage across the resonant capacitor Cr in the bipolar output resonant DC-DC converter 10 is equal to the voltage at the positive output terminal Vop. During the positive half-cycle, the energy gained by the resonant capacitor Cr is the same as the energy gained by the positive output terminal Vop; during the negative half-cycle, all the energy gained by the resonant capacitor Cr is released to the negative output terminal Von. In summary, the positive output terminal Vop and the negative output terminal Von gain the same energy, and the voltages at the positive output terminal Vop and the negative output terminal Von are equal in magnitude but opposite in polarity, thus achieving bipolar output.

[0058] Therefore, the bipolar output resonant DC-DC converter 10 provided in this application embodiment, based on the variable conversion ratio operation of the resonant network 102, enables it to provide good voltage regulation capability over a wide conversion range, thereby achieving efficient and high power density bipolar output.

[0059] Figure 6 For a schematic diagram of the operating mode of the fourth-stage bipolar output resonant DC-DC converter provided in this application, please refer to [reference needed]. Figure 6 In the fourth stage, the fourth switch S4 remains on, but the second switch S2 needs to be turned off earlier. During this stage, the first switch S1 and the third switch S3 are not yet on, and a small negative current still exists in the resonant inductor L. Due to the early turn-off of the second switch S2, the negative current flows through the fourth switch S4 and charges the input switch voltage node Vinsw through the parasitic capacitance path, raising the voltage of the input switch voltage node Vinsw to near Vin. This ensures that when the first switch S1 is about to turn on, the voltage between the drain and source of the first switch S1 is close to zero, thus achieving zero-voltage turn-on of the first switch S1. It should be noted that the turn-off time of the second switch S2 is not fixed but dynamically adjusted by the adaptive zero-voltage turn-on adjustment module 1043. If zero-voltage turn-on occurs too early, the timing of the next turn-off of the second switch S2 needs to be delayed; if zero-voltage turn-on is established too late, or even not established at all, and the system is in a hard-switching state, the timing of the next turn-off of the second switch S2 needs to be relatively earlier. In this way, it can be ensured that the voltage across the first switch S1 is zero before it is turned on, and that it is in a perfect zero-voltage start-up state, thereby reducing switch stress and losses.

[0060] Figure 7 For the operating waveform diagram of a bipolar output resonant DC-DC converter provided in this application, please refer to [reference needed]. Figure 7In the first stage, both the first switch S1 and the third switch S3 are turned on under the control of the control circuit, while both the second switch S2 and the fourth switch S4 are turned off under the control of the control circuit. The voltage at the input switch voltage node Vinsw is pulled up to near Vin by the first switch S1, and the voltage at the output switch voltage node Vosw is pulled up to the voltage at the positive output terminal Vop by the third switch S3. The voltage across the resonant network LC composed of capacitor Cr and inductor L is equal to (Vin - Vop). The input voltage Vin charges the resonant network and simultaneously supplies power to the positive output terminal Vop. The inductor current I(L) is... Starting from zero, the voltage and current I(L) increase sinusoidally. When the voltage and current reach the peak threshold set by the error amplifier, the comparator is triggered to flip, generating a control signal to control the switch switching state, entering the second stage. In the second stage, the third switch S3 remains on, the fourth switch S4 remains off, the first switch S1 is turned off under the control of the control circuit, and the second switch S2 is turned on under the control of the control circuit. The inductor current I(L) begins to decrease, but it is still positive. The voltage at the input switch voltage node Vinsw is pulled down to zero due to the on state of the second switch S2. Near the voltage level, the voltage at the output switch voltage node Vosw is still approximately the voltage at the positive output terminal Vop. Capacitor Cr continues to charge, and inductor L releases energy to maintain the continuous charging of the positive output terminal Vop and capacitor Cr. In the second stage, charge accumulation for the positive half-cycle is completed solely by the energy stored in the resonant network of the first stage. When the inductor current I(L) is 0, the zero-crossing detection circuit triggers the corresponding control signal, controlling the third switch S3 to turn off and the fourth switch S4 to turn on, thus entering the third stage. In the third stage, the first switch S1 remains off, the second switch S2 remains on, and the third switch S3... The control circuit turns off the circuit and turns on the fourth switch S4. The inductor current I(L) changes from positive to negative. The inductor current I(L) increases from zero in a sinusoidal direction. The current flows from the resonant capacitor Cr through the inductor L and then to the negative output terminal Von. The voltage of the output switch voltage node Vosw is pulled down by the fourth switch S4 to the voltage of the negative output terminal Von. The voltage of the capacitor Cr begins to drop, and the resonant capacitor Cr begins to release energy. The energy stored in the resonant capacitor Cr in the first and second stages is transferred to the negative output terminal Von through the inductor current during the negative half-cycle of the current.Therefore, based on the above analysis, the energy obtained by the positive output terminal Vop is equal to the energy obtained by the negative output terminal Von. Furthermore, if the load is the same, the voltage of the positive output terminal Vop is also equal to the voltage of the negative output terminal Von, thus achieving bipolar output with the same power. When the inductor current I(L) rises from the maximum negative current to zero, it will prepare to return to the first stage again. However, at this time, a fourth stage needs to be introduced to achieve zero-voltage turn-on of the first switch S1. In the fourth stage, the first switch S1 and the third switch S3 remain off, the fourth switch S4 remains on, and the second switch S2 needs to be turned off in advance. In this stage, there is still a small negative current in the inductor L. Due to the early turn-off of the second switch S2, the negative current flows through the fourth switch S4 and charges the input switch voltage node Vinsw through the parasitic capacitance path, raising the voltage of the input switch voltage node Vinsw to close to Vin. This makes the voltage between the drain and source of the first switch S1 close to zero voltage when the first switch S1 is about to turn on, thus achieving zero-voltage turn-on of the first switch S1. The adaptive zero-voltage turn-on adjustment module automatically generates an adaptive reference voltage ZVS_Ref, which is compared with the ramp signal generated by the ramp signal generation circuit to determine the turn-off timing of the second switch S2. Finally, through a continuous feedback adjustment mechanism, the com_zvs signal is synchronized with the Ntrigger signal, thereby ensuring the optimal zero-voltage turn-on of the first switch S1 in steady state.

[0061] In one alternative implementation, see [link to implementation details]. Figure 8 The control circuit 104 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a zero-crossing detection module 1041.

[0062] The first input terminal of the zero-crossing detection module 1041 is connected to the other end of the first capacitor 1021 and one end of the inductor 1022. The second input terminal of the zero-crossing detection module 1041 is grounded. The third input terminal of the zero-crossing detection module 1041 is connected to the input switch voltage node. The first output terminal of the zero-crossing detection module 1041 is connected to the control terminal of the third switch 1031. The second output terminal of the zero-crossing detection module 1041 is connected to the control terminal of the fourth switch 1032.

[0063] Optionally, the zero-crossing detection module 1041 is used to detect the voltage between the first capacitor 1021 and the inductor 1022 in the resonant network 102, and control the opening and closing of the third switch 1031 and the fourth switch 1032 based on the zero-crossing detection result, so as to realize the bipolar output of the bipolar output resonant DC-DC converter 10.

[0064] In one alternative implementation, see Figure 8The zero-crossing detection module 1041 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a zero-crossing detection circuit 411, a first SR flip-flop 412, a first non-overlapping clock generator 413, and an inductor current detection circuit 414.

[0065] The sampling terminal of the inductor current detection circuit 414 is connected to the other end of the first capacitor 1021 and one end of the inductor 1022. The output terminal of the inductor current detection circuit 414 is connected to the first input terminal of the zero-crossing detection circuit 411. The second input terminal of the zero-crossing detection circuit 411 is grounded. The third input terminal of the zero-crossing detection circuit 411 is connected to the input switch voltage node. The first output terminal of the zero-crossing detection circuit 411 is connected to the set terminal of the first SR flip-flop 412. The second output terminal of the zero-crossing detection circuit 411 is connected to the reset terminal of the first SR flip-flop 412. The data output terminal of the first SR flip-flop 412 is connected to the input terminal of the first non-overlapping clock generator 413. The first output terminal of the first non-overlapping clock generator 413 is connected to the control terminal of the third switch 1031. The second output terminal of the first non-overlapping clock generator 413 is connected to the control terminal of the fourth switch 1032.

[0066] It should be noted that Ntrigger refers to the output signal of the first output terminal of the zero-crossing detection circuit 411. Specifically, it can be the negative current termination signal output by the zero-crossing detection circuit 411. This application does not make any specific limitation on this.

[0067] It should also be noted that Ptrigger refers to the output signal of the second output terminal of the zero-crossing detection circuit 411. Specifically, it can be the positive half-cycle end signal output by the zero-crossing detection circuit 411. This application does not make any specific limitation on this.

[0068] In one alternative implementation, see [link to implementation details]. Figure 8 The control circuit 104 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment further includes: a peak current control module 1042 and an adaptive zero voltage turn-on adjustment module 1043.

[0069] The first input terminal of the adaptive zero-voltage turn-on adjustment module 1043 is used to receive the input signal. The second input terminal of the adaptive zero-voltage turn-on adjustment module 1043 is connected to the input switch voltage node. The third input terminal of the adaptive zero-voltage turn-on adjustment module 1043 is used to receive the power supply voltage. The fourth input terminal of the adaptive zero-voltage turn-on adjustment module 1043 is connected to the first output terminal of the zero-crossing detection circuit 411. The output terminal of the adaptive zero-voltage turn-on adjustment module 1043 is connected to the control terminal of the second switch 1012.

[0070] Optionally, the adaptive zero-voltage turn-on regulation module 1043 controls the on / off state of the second switch 1012 based on the input signal of the bipolar output resonant DC-DC converter 10 and the inductor current detected by the zero-crossing detection circuit 411.

[0071] The first input terminal of the peak current control module 1042 is connected to the output terminal of the third switch 1031. The second input terminal of the peak current control module 1042 is used to connect to a preset reference voltage. The third input terminal of the peak current control module 1042 is connected to the output terminal of the inductor current detection circuit 414. The fourth input terminal of the peak current control module 1042 is connected to the first output terminal of the zero-crossing detection circuit 411. The first output terminal of the peak current control module 1042 is connected to the control terminal of the first switch 1011. The second output terminal of the peak current control module 1042 is connected to the fifth input terminal of the adaptive zero-voltage turn-on adjustment module 1043.

[0072] Optionally, the peak current control module 1042 controls the on / off state of the first switch 1011 based on the comparison result of the positive voltage output by the positive output terminal Vop and the preset reference voltage and the effective signal of the low-level switch tube output by the zero-crossing detection circuit, and at the same time outputs the inverted signal of the control signal of the first switch 1011 to the adaptive zero-voltage start-up adjustment module 1043.

[0073] Optionally, the preset reference voltage is a voltage value preset by the user. The preset reference voltage can be +5V, +3V, etc., and this application does not make specific limitations on it.

[0074] The adaptive zero-voltage turn-on adjustment module 1043 is used to control the turn-off time of the second switch 1012 in order to control the zero-voltage turn-on state of the first switch 1011.

[0075] In one alternative implementation, see [link to implementation details]. Figure 8 The adaptive zero-voltage turn-on adjustment module 1043 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a first comparator 431, a second comparator 432, a reference voltage generation circuit 433, a ramp signal generation circuit 434, and a second SR trigger 435.

[0076] The negative input terminal of the first comparator 431 is used to receive the input signal, the positive input terminal of the first comparator 431 is connected to the input switch voltage node, the output terminal of the first comparator 431 is connected to the first input terminal of the reference voltage generation circuit 433, the second input terminal of the reference voltage generation circuit 433 is used to receive the power supply voltage, the third input terminal of the reference voltage generation circuit 433 is connected to the first output terminal of the zero-crossing detection circuit 411, and the output terminal of the reference voltage generation circuit 433 is connected to the negative input terminal of the second comparator 432. The data output terminal of the second SR flip-flop 435 is connected to the control terminal of the second switch 1012. The inverting output terminal of the second SR flip-flop 435 is connected to the control terminal of the ramp signal generating circuit 434. The input terminal of the ramp signal generating circuit 434 is used to connect to the power supply voltage. The output terminal of the ramp signal generating circuit 434 is connected to the positive input terminal of the second comparator 432. The output terminal of the second comparator 432 is connected to the reset terminal of the second SR flip-flop 435. The set terminal of the second SR flip-flop 435 is connected to the second output terminal of the peak current control module 1042.

[0077] Optionally, the power supply voltage is the voltage provided by the positive power supply, denoted by Vdd, and Vss represents ground.

[0078] It should be noted that the set terminal of the SR flip-flop is S, the reset terminal of the SR flip-flop is R, and the data output terminal or output terminal of the SR flip-flop is Q.

[0079] In one alternative implementation, see [link to implementation details]. Figure 8 The reference voltage generation circuit 433 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a first D flip-flop 4331, a second D flip-flop 4332, a NAND gate 4333, a first current source 4334, a second current source 4335, a second capacitor 4336, a fifth switch 4337, and a sixth switch 4338.

[0080] In this D flip-flop, D is the data input, CLK is the clock input, RST is the reset input, and Q is the data output.

[0081] The clock input of the first D flip-flop 4331 is connected to the output of the first comparator 431. The data inputs of both the first D flip-flop 4331 and the second D flip-flop 4332 are connected to the power supply voltage. The clock input of the second D flip-flop 4332 is connected to the first output of the zero-crossing detection circuit 411. The data output of the first D flip-flop 4331 is connected to the control terminal of the fifth switch 4337 and the first input of the NAND gate 4333. The data output of the second D flip-flop 4332 is connected to the control terminal of the sixth switch 4338 and the second input of the NAND gate 4333. The output of the NAND gate 4333 is connected to the reset terminals of the first D flip-flop 4331 and the second D flip-flop 4332.

[0082] The input terminal of the first current source 4334 is used to connect to the power supply voltage. The output terminal of the first current source 4334 is connected to the input terminal of the fifth switch 4337. The output terminal of the fifth switch 4337 is connected to one end of the second capacitor 4336, the input terminal of the sixth switch 4338, and the negative input terminal of the second comparator 432. The output terminal of the sixth switch 4338 is connected to the input terminal of the second current source 4335. The output terminal of the second current source 4335 and the other end of the second capacitor 4336 are both grounded.

[0083] Optionally, the first current source 4334 is a charging current source, and the second current source 4335 is a discharging current source.

[0084] In one alternative implementation, see [link to implementation details]. Figure 8 The ramp signal generation circuit 434 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a P-type metal-oxide-semiconductor transistor 4341, an N-type metal-oxide-semiconductor transistor 4342, a third current source 4343, and a third capacitor 4344.

[0085] The gates of the P-type metal-oxide-semiconductor transistor 4341 and the N-type metal-oxide-semiconductor transistor 4342 are connected to the inverting output of the second SR flip-flop 435. The source of the P-type metal-oxide-semiconductor transistor 4341 is connected to the output of the third current source 4343. The input of the third current source 4343 is used to connect to the power supply voltage. The drains of the P-type metal-oxide-semiconductor transistor 4341 and the drains of the N-type metal-oxide-semiconductor transistor 4342 are respectively connected to the positive input of the second comparator 432 and one end of the third capacitor 4344. The source of the N-type metal-oxide-semiconductor transistor 4342 and the other end of the third capacitor 4344 are both grounded.

[0086] In one alternative implementation, see [link to implementation details]. Figure 8 The peak current control module 1042 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a voltage divider network 421, a compensation network 422, a current-voltage converter 423, a third comparator 424, a third SR flip-flop 425, and a second non-overlapping clock generator 426.

[0087] The input terminal of voltage divider network 421 is connected to the output terminal of third switch 1031, the first output terminal of voltage divider network 421 is connected to the first input terminal of compensation network 422, and the second output terminal of voltage divider network 421 is grounded. The second input terminal of the compensation network 422 is used to connect to a preset reference voltage. The output terminal of the compensation network 422 is connected to the negative input terminal of the third comparator 424. The positive input terminal of the third comparator 424 is connected to the output terminal of the current-to-voltage converter 423. The input terminal of the current-to-voltage converter 423 is connected to the output terminal of the inductor current detection circuit 414. The reset terminal of the third SR flip-flop 425 is connected to the output terminal of the third comparator 424, the set terminal of the third SR flip-flop 425 is connected to the first output terminal of the zero-crossing detection circuit 411, the data output terminal of the third SR flip-flop 425 is connected to the input terminal of the second non-overlapping clock generator 426, the first output terminal of the second non-overlapping clock generator 426 is connected to the control terminal of the first switch 1011, and the second output terminal of the second non-overlapping clock generator 426 is connected to the fifth input terminal of the adaptive zero-voltage turn-on adjustment module 1043.

[0088] In one alternative implementation, see [link to implementation details]. Figure 8 The voltage divider network 421 in the bipolar output resonant DC-DC converter 10 provided in this application embodiment includes: a first resistor 4211 and a second resistor 4212, and the compensation network 422 includes: an error amplifier 4221, a fourth capacitor 4222, a fifth capacitor 4223 and a third resistor 4224.

[0089] One end of the first resistor 4211 is connected to the output terminal of the third switch 1031. The other end of the first resistor 4211 is connected to one end of the second resistor 4212 and the negative input terminal of the error amplifier 4221. The positive input terminal of the error amplifier 4221 is used to connect to a preset reference voltage. The other end of the second resistor 4212 is grounded. The negative input terminal of the error amplifier 4221 is also connected to one end of the third resistor 4224 and one end of the fourth capacitor 4222. The other end of the third resistor 4224 is connected to one end of the fifth capacitor 4223. The other ends of the fourth capacitor 4222 and the other ends of the fifth capacitor 4223 are both connected to the output terminal of the error amplifier 4221. The output terminal of the error amplifier 4221 is also connected to the negative output terminal of the third comparator 424.

[0090] It should be noted that the four power switches, namely the first switch 1011, the second switch 1012, the third switch 1031 and the fourth switch 1032, in the bipolar output resonant DC-DC converter 10 provided in this application embodiment are two pairs of half-bridge structures controlled by non-overlapping signals. By controlling the switching sequence of each power switch, zero-voltage turn-on operation is achieved to reduce hard switching losses.

[0091] It should also be noted that the level shifting circuit and gate drive buffer 170 of the first switch are used to apply a corresponding drive signal to the gate of the first switch S1 to control the on / off state of the first switch S1; the level shifting circuit and gate drive buffer 171 of the third switch are used to apply a corresponding drive signal to the gate of the third switch S3 to control the on / off state of the third switch S3; the level shifting circuit and gate drive buffer 180 of the second switch are used to apply a corresponding drive signal to the gate of the second switch S2 to control the on / off state of the second switch S2; and the level shifting circuit and gate drive buffer 190 of the fourth switch are used to output a corresponding drive signal to the gate of the fourth switch S4 to control the on / off state of the fourth switch S4.

[0092] Figure 9 For a freewheeling schematic diagram of the state switching of the first bipolar output resonant DC-DC converter provided in this application, see [link to schematic diagram]. Figure 9 During the switching process of the bipolar output resonant DC-DC converter 10 from the first stage to the second stage, the first switch S1 is turned off and the second switch S2 is about to turn on. At this time, during the dead time, since the current direction of the inductor L is positive, the inductor current cannot change abruptly. The inductor current is instead provided by the body diode of the second switch S2 for forward freewheeling. Therefore, the voltage of the input switch voltage node Vinsw will drop to VSS (ground) - Vdiode (Vdiode is the forward voltage drop of the parasitic body diode of the power switch) before the second switch S2 turns on. This will make the voltage difference across the second switch S2 close to zero before the second switch S2 is officially turned on, and there is no overlap loss caused by the switch. Therefore, the second switch S2 is a naturally zero-voltage turn-on transistor.

[0093] Figure 10 For a freewheeling schematic diagram of the state switching of the second type of bipolar output resonant DC-DC converter provided in this application, please refer to [reference needed]. Figure 10During the transition from the second stage to the third stage of the bipolar output resonant DC-DC converter 10, the third switch S3 is turned off, and the fourth switch S4 is about to turn on. During this transition, the inductor current is about to switch from positive to negative, and this is detected and triggered by the zero-crossing detection circuit. Due to the signal propagation delay between the zero-crossing detection circuit and the logic gate circuit, the inductor current of inductor L has already changed from positive to negative before the fourth switch S4 turns on. At this time, the body diode of the fourth switch S4 conducts, providing negative freewheeling current for the inductor current. Therefore, the voltage at the output switch voltage node Vosw is pulled down to Von-Vdiode (Vdiode is the forward voltage drop of the parasitic body diode of the power switch) due to the conduction of the body diode of the fourth switch S4. This makes the voltage difference between the drain and source of the fourth switch S4 close to 0 before the fourth switch S4 is fully turned on, thus eliminating the overlapping losses caused by voltage and current when the fourth switch S4 turns on. Therefore, the fourth switch S4 is a naturally zero-voltage turn-on transistor.

[0094] Figure 11 For a freewheeling schematic diagram of the state switching of the third type of bipolar output resonant DC-DC converter provided in this application, please refer to [reference needed]. Figure 11 In the case where the bipolar output resonant DC-DC converter 10 does not incorporate an adaptive zero-voltage switching mode, the second switch S2 and the fourth switch S4 are turned off, and the first switch S1 and the third switch S3 are about to turn on. The inductor current is about to switch from negative to positive, and this moment is detected and triggered by the zero-crossing detection circuit. Due to the signal propagation delay between the zero-crossing detection circuit and the logic gate circuit, the inductor current has already flipped from positive to negative to negative to positive before the third switch S3 turns on. At this time, the body diode of the third switch S3 is conducting to provide a freewheeling path for the positive inductor current. This makes the voltage difference between the drain and source of the third switch S3 close to 0 before the third switch S3 is fully turned on, so that there is no overlap loss caused by voltage and current when the third switch S3 turns on. Therefore, the third switch S3 is a natural zero-voltage turn-on transistor. However, for the first switch S1, its body diode points from the input switch voltage node Vinsw to the input terminal Vin. Therefore, before the first switch S1 is turned on, a slightly greater than zero forward inductor current freewheels through the body diode of the second switch S2, not the first switch S1. Furthermore, the voltage at the input switch voltage node Vinsw before the first switch S1 is turned on is VSS - Vdiode. However, since the current flowing through the first switch S1 is close to zero, the first switch S1 is a zero-current turn-on power switch, not a zero-voltage turn-on switch. But because the parasitic capacitance on the first switch S1 still needs to discharge when it is turned on, this results in significant voltage and current overlap losses. Therefore, the first switch S1 is a hard switch.

[0095] Figure 12For the waveform diagram of the bipolar output resonant DC-DC converter provided in this application within a preset duty cycle, please refer to [link / reference]. Figure 12 In the first stage, both the first switch S1 and the third switch S3 are turned on under the control of the control circuit, while the second switch S2 and the fourth switch S4 are turned off under the control of the control circuit. The inductor current of the resonant inductor L is a positive current, and the inductor current increases sinusoidally from 0. The input switch voltage node Vinsw is pulled up to the input voltage Vin due to the conduction of the first switch S1. In the second stage, the third switch S3 remains on, the fourth switch S4 remains off, the first switch S1 is turned off under the control of the control circuit, and the second switch S2 is turned on under the control of the control circuit. The inductor current of the resonant inductor L is still a positive current, but the resonant current decreases in the positive direction and approaches 0. The input switch voltage node Vinsw is pulled down to zero due to the turn-off of the first switch S1 and the conduction of the second switch S2. In the third stage, the first switch S1 remains off, the second switch S2 remains on, the third switch S3 is turned off under the control of the control circuit, and the fourth switch S4 is turned on under the control of the control circuit. At this point, the current direction of the resonant inductor L becomes negative, and the inductor current increases sinusoidally from 0. The input switch node Vinsw remains at zero voltage due to the continued conduction of the second switch S2. In the fourth stage, the first switch S1 and the third switch S3 remain off, the fourth switch S4 remains on, and the second switch S2 is turned off early under the control of the adaptive zero-voltage turn-on circuit. Since the first switch S1 and the second switch S2 are both off, the input switch node becomes a high-resistance node. At the same time, since the inductor current of the resonant inductor L is still negative and decreases from the peak of the negative current to 0, the input switch node Vinsw, which is in a high-resistance state, is pre-charged, and finally, the first switch S1 is perfectly soft-turned at the beginning of the next stage.

[0096] Figure 13 For the working waveform diagram of the zero-voltage start-up of the first switch provided in this application, please refer to [reference needed]. Figure 13 When the second switch S2 is turned off in advance under the control of the adaptive zero-voltage turn-on circuit, the bipolar output resonant DC-DC converter 10 charges the input switch voltage node Vinsw through the negative resonant current of the resonant network 102. The voltage difference across the first switch S1 decreases continuously from VIN until it drops to zero. The pre-charging stage of the Vinsw node is completed, thus making the soon-to-be-conducted S1 turn on with zero voltage.

[0097] Figure 14 For a freewheeling schematic diagram of the state switching of the fourth type of bipolar output resonant DC-DC converter provided in this application, please refer to [reference needed]. Figure 14In the case of the adaptive zero-voltage switching mode added to the bipolar output resonant DC-DC converter 10, the second switch S2 is no longer turned off by the zero-crossing detection circuit from negative to positive, but is controlled by the adaptive zero-voltage turn-on adjustment module 1043. In the third stage of the bipolar output resonant DC-DC converter 10, the inductor current of the bipolar output resonant DC-DC converter 10 is negative. The negative inductor current in the third stage is used to charge the input switch voltage node Vinsw, so that the voltage of the input switch voltage node Vinsw reaches the voltage of the input terminal Vin or Vin+Vdiode before the first switch S1 is turned on.

[0098] To achieve the above function, the second switch S2 needs to be turned off in advance before the bipolar output resonant DC-DC converter 10 completes the third stage. Turning off the second switch S2 in advance will not affect the power transmission of the bipolar output resonant DC-DC converter 10.

[0099] Furthermore, the turn-off timing of the second switch S2 is determined by the adaptive zero-voltage turn-on adjustment module 1043. If the second switch S2 turns off too early, the dead time will be too long, resulting in an excessively long conduction time for the body diode of the first switch S1. While this alleviates switching losses, it also causes excessive body diode conduction losses. Therefore, this application can continuously optimize the turn-off time of the second switch S2 through a feedback adjustment mechanism, enabling the second switch S2 to turn off at the most appropriate time, thereby achieving zero-voltage turn-on for all power switches and fully leveraging the advantages of the resonant network 102.

[0100] For example, if the input voltage of the bipolar output resonant DC-DC converter is 36V, the output voltage is ±5V, and the output current is 2A, the working process and adaptive zero-voltage regulation process of the bipolar output resonant DC-DC converter are as follows: First, when the bipolar output resonant DC-DC converter is in the first stage, both the first switch S1 and the third switch S3 are turned on. The input signal Vin simultaneously charges the positive output terminal Vop and the resonant network LC. All currents flow through the inductor L. The voltage difference Vc across the resonant capacitor Cr and the current across the inductor L both show a sinusoidal trend and continue to rise. At this time, the voltage difference across the resonant network LC is Vin-Vop. During this process, the positive output terminal Vop and the resonant capacitor Cr receive the same charge Q1. The inductor current is converted into a voltage signal of the equivalent sensing resistance Ri through the zero-crossing detection circuit (where Ri is the gain of the zero-crossing detection circuit), and compared with the error amplification signal Vea of ​​the output voltage. The output signal Vcom of the third comparator is used as a control signal to reset the third SR flip-flop. The clock signal CLK1 is at a low level, and then the clock signal CLK1 causes the gate drive signal of the first switch S1 to drop to a low level through the second non-overlapping clock generator, so as to drive the first switch S1 to turn off. At the same time, its complementary signal (the signal received by the set terminal of the second SR flip-flop 435) rises to a high level, and again serves as a control signal. Through the set signal of the second SR flip-flop, the gate drive signal of the second switch S2 is pulled up to a high level, so as to drive the third switch S3 to open. The bipolar output resonant DC-DC converter enters the second stage.

[0101] Secondly, in the second stage, the voltage difference across the resonant network LC changes from Vin-Vop to -Vop, and the inductor L begins to release energy. The inductor current gradually decreases in a sinusoidal waveform. Compared to the first stage, due to the increased voltage difference across the resonant network LC, the rate of change of the inductor current accelerates, but the current direction remains unchanged (still positive). The voltage difference Vc across the resonant capacitor Cr continues to rise in a sinusoidal trend, and the positive output terminal Vop and the resonant capacitor Cr continue to acquire charge Q2. When the zero-crossing detection circuit detects that the inductor current of the inductor L in the resonant network LC has decreased to zero, the output terminal positive half-cycle end signal Ptrigger is triggered, outputting a high-level pulse signal to reset the gate of the third switch S3 and the first SR flip-flop connected to the gate of the fourth switch S4. This causes the clock signal CLK2 to drop to a low level. The clock signal CLK2 then drives the gate drive signal of the third switch S3 to drop to a low level and the gate drive signal of the fourth switch S4 to rise to a high level through the first non-overlapping clock generator, so that the third switch S3 is turned off and the fourth switch S4 is turned on, thus completing the second stage.

[0102] During the entire positive half-cycle of the inductor current, the inductor L does not accumulate energy; it only serves to transfer charge and energy. This will ensure that both the positive output terminal Vop and the resonant capacitor Cr receive the same amount of charge Q1+Q2.

[0103] In the third stage, the bipolar output resonant DC-DC converter enters the reverse energy transfer stage. Utilizing the periodic change in the direction of the resonant current in the LC resonant network, the resonant current direction is negative, drawing charge Q3 from the negative output terminal Von. At this time, since there is only one path for inductor L to discharge, the amount of charge released by capacitor Cr is equal to the amount of charge released by the negative output terminal Von. According to the law of conservation of charge, Q1 + Q2 = Q3, that is, Qop = |Qon|. Furthermore, before entering the third stage, there is no energy stored in inductor L; all energy is stored in the resonant capacitor Cr. After a complete negative half-cycle of resonant operation, the resonant current decreases continuously from negative and then crosses zero, flipping to positive. The negative current end signal Ntrigger of the zero-crossing detection circuit is triggered, outputting a high-level pulse signal, which sets clock signals CLK1 and CLK2 to high level, thereby driving the first switch S1 and the third switch S3 to open and the fourth switch S4 to close. The bipolar output resonant DC-DC converter then re-enters the first stage. Based on the principles of energy and charge conservation and energy conservation, the positive output terminal Vop and the negative output terminal Von obtain the same energy, and the voltage magnitudes of the positive output terminal Vop and the negative output terminal Von are equal but the polarities are opposite, thus achieving a bipolar output of ±5V.

[0104] Furthermore, in the third stage of the adaptive zero-voltage operating mode, the turn-off of the second switch S2 is no longer triggered by the negative current termination signal Ntrigger, but is controlled by the adaptive zero-voltage turn-on regulation module designed in this application. See also Figure 12 , Figure 13 , Figure 14 as well as Figure 8The control logic and circuit structure of the adaptive zero-voltage turn-on adjustment module are shown. During the turn-on phase of the second switch S2, the inverted signal of the gate drive signal of the second switch S2 is low, and the ramp signal generation circuit is activated. When the voltage on the upper plate of capacitor Ccharge rises to the adaptive reference voltage ZVS_Ref generated by the PLL (phase-locked loop), the third comparator generates a reset signal S3RST for the second switch S2 to turn off the second switch S2 in advance. At this time, the inductor current of inductor L in the resonant network LC is still a negative current. The negative current in this additional stage (fourth stage) is used to charge the input switch voltage node Vinsw, so that before the first switch S1 is turned on, the voltage value of the input switch voltage node Vinsw reaches the voltage value of the input signal Vin (or Vin+Vdiode), thereby realizing the soft start of the first switch S1. When the first switch S1 establishes a zero-voltage turn-on state, the voltage value of the input switch voltage node Vinsw is greater than the voltage value of the input signal Vin. The third comparator, as the identification circuit for the completion of the zero-voltage state establishment, generates a com_zvs signal. The peak current control module compares the com_zvs signal with the negative current end signal Ntrigger to identify the phase difference. If the com_zvs signal precedes the negative current end signal Ntrigger, it indicates that the second switch S2 turns off too early. The first D flip-flop controlling the charging current is set to raise the adaptive reference voltage ZVS_Ref potential, thus delaying the turn-off time of the second switch S2. If the com_zvs signal lags behind the negative current end signal Ntrigger, it indicates that the second switch S2 turns off too late. The second D flip-flop controlling the discharge current is set to slowly discharge the adaptive reference voltage ZVS_Ref, thus advancing the turn-off time of the second switch S2. Under steady state, the com_zvs signal is synchronized with the negative current termination signal Ntrigger through the phase-locked loop (PLL) so that the adaptive reference voltage ZVS_Ref that controls the second switch S2 to turn off remains unchanged, the adaptive adjustment of zero voltage opening is completed, and the first switch S1 remains in the zero voltage open state.

[0105] Figure 15 For a schematic diagram of a bipolar output power supply provided in this application, see [link to schematic diagram]. Figure 15 This application provides a bipolar output power supply 20, in which the aforementioned bipolar output resonant DC-DC converter 10 is deployed. The operating principle of the bipolar output power supply 20 is the same as that of the aforementioned bipolar output resonant DC-DC converter 10, and will not be described in detail here.

[0106] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0107] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A bipolar output resonant DC-DC converter, characterized in that, The bipolar output resonant DC-DC converter includes: an input half-bridge, a resonant network, an output half-bridge, and a control circuit. The output terminal of the control circuit is connected to the control terminal of the input half-bridge and the control terminal of the output half-bridge, respectively. The input terminal of the input half-bridge is used to receive the input signal. The first output terminal of the input half-bridge is connected to one end of the resonant network, and the second output terminal of the input half-bridge is grounded. The other end of the resonant network is connected to the input end of the output half-bridge. The first output end and the second output end of the output half-bridge are both connected to an external load. The first output end of the output half-bridge is used to output a positive voltage, and the second output end of the output half-bridge is used to output a negative voltage. The resonant network is used to transfer energy between the input half-bridge and the output half-bridge. The input half-bridge and the output half-bridge are cyclically turned on or off within a preset working cycle under the action of the control signal output by the control circuit, so as to realize the bidirectional energy transfer of the resonant network.

2. The bipolar output resonant DC-DC converter according to claim 1, characterized in that, The resonant network includes a first capacitor and an inductor; the input half-bridge includes a first switch and a second switch; the output half-bridge includes a third switch and a fourth switch. One end of the first capacitor is connected to the output terminal of the first switch and the input terminal of the second switch, and the other end of the first capacitor is connected to one end of the inductor. The other end of the inductor is connected to the input terminal of the third switch and the input terminal of the fourth switch. The input terminal of the first switch is used to receive an input signal, and the output terminal of the first switch is also connected to the input terminal of the second switch, and the output terminal of the second switch is grounded; the input terminal of the third switch is also connected to the input terminal of the fourth switch, and the output terminals of the third switch and the fourth switch are both connected to an external load; The control terminals of the first switch, the second switch, the third switch, and the fourth switch are all connected to the output terminal of the control circuit. The voltage node connecting the output terminal of the first switch and the input terminal of the second switch serves as the input switch voltage node, and the voltage node connecting the input terminal of the third switch and the input terminal of the fourth switch serves as the output switch voltage node. The output terminal of the third switch is used to output a positive voltage, and the output terminal of the fourth switch is used to output a negative voltage.

3. The bipolar output resonant DC-DC converter according to claim 2, characterized in that, The control circuit includes: a zero-crossing detection module; The first input terminal of the zero-crossing detection module is connected to the other end of the first capacitor and one end of the inductor. The second input terminal of the zero-crossing detection module is grounded. The third input terminal of the zero-crossing detection module is connected to the input switch voltage node. The first output terminal of the zero-crossing detection module is connected to the control terminal of the third switch. The second output terminal of the zero-crossing detection module is connected to the control terminal of the fourth switch.

4. The bipolar output resonant DC-DC converter according to claim 3, characterized in that, The zero-crossing detection module includes: an inductor current detection circuit, a zero-crossing detection circuit, a first SR flip-flop, and a first non-overlapping clock generator; The sampling terminal of the inductor current detection circuit is connected to the other end of the first capacitor and one end of the inductor. The output terminal of the inductor current detection circuit is connected to the first input terminal of the zero-crossing detection circuit. The second input terminal of the zero-crossing detection circuit is grounded. The third input terminal of the zero-crossing detection circuit is connected to the input switch voltage node. The first output terminal of the zero-crossing detection circuit is connected to the set terminal of the first SR flip-flop. The second output terminal of the zero-crossing detection circuit is connected to the reset terminal of the first SR flip-flop. The data output terminal of the first SR flip-flop is connected to the input terminal of the first non-overlapping clock generator. The first output terminal of the first non-overlapping clock generator is connected to the control terminal of the third switch. The second output terminal of the first non-overlapping clock generator is connected to the control terminal of the fourth switch.

5. The bipolar output resonant DC-DC converter according to claim 4, characterized in that, The control circuit also includes: a peak current control module and an adaptive zero-voltage turn-on adjustment module; The first input terminal of the adaptive zero-voltage turn-on adjustment module is used to receive the input signal, the second input terminal of the adaptive zero-voltage turn-on adjustment module is connected to the input switch voltage node, the third input terminal of the adaptive zero-voltage turn-on adjustment module is used to receive the power supply voltage, the fourth input terminal of the adaptive zero-voltage turn-on adjustment module is connected to the first output terminal of the zero-crossing detection circuit, and the output terminal of the adaptive zero-voltage turn-on adjustment module is connected to the control terminal of the second switch. The first input terminal of the peak current control module is connected to the output terminal of the third switch, the second input terminal of the peak current control module is used to connect to a preset reference voltage, the third input terminal of the peak current control module is connected to the output terminal of the inductor current detection circuit, the fourth input terminal of the peak current control module is connected to the first output terminal of the zero-crossing detection circuit, the first output terminal of the peak current control module is connected to the control terminal of the first switch, and the second output terminal of the peak current control module is connected to the fifth input terminal of the adaptive zero-voltage turn-on adjustment module. The adaptive zero-voltage turn-on adjustment module is used to control the turn-off time of the second switch in order to control the zero-voltage turn-on of the first switch.

6. The bipolar output resonant DC-DC converter according to claim 5, characterized in that, The adaptive zero-voltage turn-on adjustment module includes: a first comparator, a second comparator, a reference voltage generation circuit, a ramp signal generation circuit, and a second SR flip-flop; The negative input terminal of the first comparator is used to receive the input signal, the positive input terminal of the first comparator is connected to the input switch voltage node, the output terminal of the first comparator is connected to the first input terminal of the reference voltage generation circuit, the second input terminal of the reference voltage generation circuit is used to receive the power supply voltage, the third input terminal of the reference voltage generation circuit is connected to the first output terminal of the zero-crossing detection circuit, and the output terminal of the reference voltage generation circuit is connected to the negative input terminal of the second comparator. The data output terminal of the second SR flip-flop is connected to the control terminal of the second switch, the inverting output terminal of the second SR flip-flop is connected to the control terminal of the ramp signal generation circuit, the input terminal of the ramp signal generation circuit is used to connect to the power supply voltage, the output terminal of the ramp signal generation circuit is connected to the positive input terminal of the second comparator, the output terminal of the second comparator is connected to the reset terminal of the second SR flip-flop, and the set terminal of the second SR flip-flop is connected to the second output terminal of the peak current control module.

7. The bipolar output resonant DC-DC converter according to claim 6, characterized in that, The reference voltage generation circuit includes: a first D flip-flop, a second D flip-flop, a NAND gate, a first current source, a second current source, a second capacitor, a fifth switch, and a sixth switch; The clock input of the first D flip-flop is connected to the output of the first comparator. The data inputs of both the first and second D flip-flops are connected to the power supply voltage. The clock input of the second D flip-flop is connected to the first output of the zero-crossing detection circuit. The data output of the first D flip-flop is connected to the control terminal of the fifth switch and the first input of the NAND gate. The data output of the second D flip-flop is connected to the control terminal of the sixth switch and the second input of the NAND gate. The output of the NAND gate is connected to the reset terminals of the first and second D flip-flops. The input terminal of the first current source is used to connect to the power supply voltage. The output terminal of the first current source is connected to the input terminal of the fifth switch. The output terminal of the fifth switch is connected to one end of the second capacitor, the input terminal of the sixth switch, and the negative input terminal of the second comparator. The output terminal of the sixth switch is connected to the input terminal of the second current source. The output terminal of the second current source and the other end of the second capacitor are both grounded.

8. The bipolar output resonant DC-DC converter according to claim 6, characterized in that, The ramp signal generation circuit includes: a P-type metal-oxide-semiconductor transistor, an N-type metal-oxide-semiconductor transistor, a third current source, and a third capacitor. The gates of the P-type metal-oxide-semiconductor transistor and the N-type metal-oxide-semiconductor transistor are connected to the inverting output of the second SR flip-flop. The source of the P-type metal-oxide-semiconductor transistor is connected to the output of the third current source. The input of the third current source is used to connect to the power supply voltage. The drains of the P-type metal-oxide-semiconductor transistor and the N-type metal-oxide-semiconductor transistor are respectively connected to the positive input of the second comparator and one end of the third capacitor. The source of the N-type metal-oxide-semiconductor transistor and the other end of the third capacitor are both grounded.

9. The bipolar output resonant DC-DC converter according to claim 5, characterized in that, The peak current control module includes: a voltage divider network, a compensation network, a current-to-voltage converter, a third comparator, a third SR flip-flop, and a second non-overlapping clock generator. The input terminal of the voltage divider network is connected to the output terminal of the third switch, the first output terminal of the voltage divider network is connected to the first input terminal of the compensation network, and the second output terminal of the voltage divider network is grounded. The second input terminal of the compensation network is used to connect to a preset reference voltage. The output terminal of the compensation network is connected to the negative input terminal of the third comparator. The positive input terminal of the third comparator is connected to the output terminal of the current-voltage converter. The input terminal of the current-voltage converter is connected to the output terminal of the inductor current detection circuit. The reset terminal of the third SR flip-flop is connected to the output terminal of the third comparator, the set terminal of the third SR flip-flop is connected to the first output terminal of the zero-crossing detection circuit, the data output terminal of the third SR flip-flop is connected to the input terminal of the second non-overlapping clock generator, the first output terminal of the second non-overlapping clock generator is connected to the control terminal of the first switch, and the second output terminal of the second non-overlapping clock generator is connected to the fifth input terminal of the adaptive zero-voltage turn-on adjustment module.

10. The bipolar output resonant DC-DC converter according to claim 9, characterized in that, The voltage divider network includes a first resistor and a second resistor, and the compensation network includes an error amplifier, a fourth capacitor, a fifth capacitor, and a third resistor. One end of the first resistor is connected to the output terminal of the third switch, and the other end of the first resistor is connected to one end of the second resistor and the negative input terminal of the error amplifier. The positive input terminal of the error amplifier is used to connect to a preset reference voltage, and the other end of the second resistor is grounded. The negative input terminal of the error amplifier is also connected to one end of the third resistor and one end of the fourth capacitor. The other end of the third resistor is connected to one end of the fifth capacitor. The other ends of the fourth capacitor and the fifth capacitor are both connected to the output terminal of the error amplifier. The output terminal of the error amplifier is also connected to the negative output terminal of the third comparator.

Images