DC-DC switching power supply control circuit based on phase-shifted full-bridge converter

Abstract

The utility model relates to the technical field of control circuits, in particular to a DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter, which comprises an inverter circuit, a resonance circuit, a rectifying circuit and a filter circuit which are electrically connected, a transformer excitation inductor Lm is arranged on a transformer Tr in parallel, and a transformer leakage inductor Lr and a blocking capacitor Cr are arranged on the transformer Tr in series; a boost circuit is electrically connected between the transformer leakage inductor Lr and the blocking capacitor Cr, and the boost circuit comprises a diode VD1 and an MOS tube T5. The inverter circuit, the resonance circuit, the rectification circuit and the filter circuit are easy to realize high frequency, the main circuit is simple in structure, and soft switching is realized by adding resonance elements such as small inductors and capacitors and introducing resonance conditions before and after the switching process due to the advantages of large output power, high efficiency, simple control, electrical isolation and the like.

Description

Technical Field

[0001] This utility model relates to a switching power supply control circuit, and more particularly to a DC-DC switching power supply control circuit based on a phase-shifting full-bridge converter, belonging to the field of control circuit technology. Background Technology

[0002] DC-DC converters play a crucial role in electronic devices, not only converting voltage and stabilizing output, but also regulating current according to load demands, managing energy, and monitoring power distribution. With the continuous development of electronic technology, DC-DC converters will be widely used and play an even greater role in more fields.

[0003] Traditional full-bridge DC-DC converters generally use metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated-gate bipolar transistors (IGBTs) as the main switching devices. IGBTs have the characteristics of large current, high voltage resistance, high switching speed, low rated switching frequency, and large single switching loss. Therefore, large inductors and capacitors are required for filtering components, which affects the overall size of the power supply and is not suitable for high-frequency applications.

[0004] Therefore, it is urgent to improve the control circuit of DC-DC switching power supply based on phase-shifted full-bridge converter to solve the above-mentioned problems. Utility Model Content

[0005] The purpose of this invention is to provide a DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter. The full-bridge DC-DC converter is a DC-DC conversion circuit suitable for high-power switching power supplies, consisting of an inverter circuit, a resonant circuit, a rectifier circuit, and a filter circuit. It is easy to achieve high frequency operation and has a simple main circuit structure. By adding resonant components such as small inductors and capacitors, resonant conditions are introduced before and after the switching process to achieve soft switching. It benefits from advantages such as high output power, high efficiency, simple control, and electrical isolation.

[0006] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0007] A DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter includes an inverter circuit, a resonant circuit, a rectifier circuit, and a filter circuit that are electrically connected. The resonant circuit is electrically connected to the rectifier circuit through a transformer Tr. A transformer magnetizing inductor Lm is connected in parallel on the transformer Tr, and a transformer leakage inductance Lr and a DC blocking capacitor Cr are connected in series on the transformer Tr.

[0008] A boost circuit is electrically connected between the transformer leakage inductance Lr and the DC blocking capacitor Cr. The boost circuit includes a diode VD1 and a MOSFET T5. The diode VD1 is electrically connected between the transformer leakage inductance Lr and the DC blocking capacitor Cr. A capacitor C2 and a resistor RL are connected in parallel on the MOSFET T5.

[0009] Preferably, an inductor L is electrically connected between the diode VD1 and the DC blocking capacitor Cr, and the inductor L is electrically connected to the inverter circuit through the DC blocking capacitor Cr.

[0010] Preferably, the inverter circuit includes main switch T1, main switch T2, main switch T3, and main switch T4. Main switch T1 and main switch T2 are electrically connected to the DC blocking capacitor Cr, and main switch T3 and main switch T4 are electrically connected to the transformer magnetizing inductance Lm.

[0011] Preferably, the main switch transistors T1 and T2 are connected in series, and the main switch transistors T3 and T4 are connected in series and then a capacitor C1 is connected in parallel.

[0012] Preferably, the rectifier circuit includes diodes VD2 and VD3, and the middle part of the transformer Tr is electrically connected to the filter circuit.

[0013] Preferably, the filter circuit includes a transistor VT1, the base pin of the transistor VT1 is grounded through a capacitor C3, and a capacitor C4 and a resistor R2 are connected in parallel on the emitter pin of the transistor VT1.

[0014] Preferably, a resistor R1 and a diode VD4 are connected in series on the collector pin of the transistor VT1.

[0015] This utility model has at least the following beneficial effects:

[0016] A full-bridge DC-DC converter is a DC-DC conversion circuit suitable for high-power switching power supplies. It includes an inverter circuit, a resonant circuit, a rectifier circuit, and a filter circuit. It is easy to achieve high frequency and has a simple main circuit structure. By adding small inductors, capacitors, and other resonant components, resonant conditions are introduced before and after the switching process to achieve soft switching. It benefits from its advantages such as high output power, high efficiency, simple control, and electrical isolation. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1This is the electrical schematic diagram of the present invention;

[0019] Figure 2 This is the circuit diagram of this utility model;

[0020] Figure 3 This is the filter circuit diagram of this utility model.

[0021] In the diagram, 1 is the inverter circuit; 2 is the resonant circuit; 3 is the rectifier circuit; 4 is the filter circuit; and 5 is the boost circuit. Detailed Implementation

[0022] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0023] like Figures 1-3 As shown, the DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter provided in this embodiment includes an inverter circuit 1, a resonant circuit 2, a rectifier circuit 3, and a filter circuit 4 that are electrically connected. The resonant circuit 2 is electrically connected to the rectifier circuit 3 through a transformer Tr. A transformer magnetizing inductor Lm is connected in parallel on the transformer Tr, and a transformer leakage inductance Lr and a DC blocking capacitor Cr are connected in series on the transformer Tr. The full-bridge DC-DC converter is a DC-DC conversion circuit suitable for high-power switching power supplies. The inverter circuit 1, resonant circuit 2, rectifier circuit 3, and filter circuit 4 are easy to implement at high frequencies and have a simple main circuit structure. By adding small inductors, capacitors, and other resonant components, resonant conditions are introduced before and after the switching process to achieve soft switching. It benefits from its advantages such as high output power, high efficiency, simple control, and electrical isolation.

[0024] A boost circuit 5 is electrically connected between the transformer leakage inductance Lr and the DC blocking capacitor Cr. The boost circuit 5 includes a diode VD1 and a MOSFET T5. Diode VD1 is electrically connected between the transformer leakage inductance Lr and the DC blocking capacitor Cr. A capacitor C2 and a resistor RL are connected in parallel on the MOSFET T5. An inductor L is electrically connected between the diode VD1 and the DC blocking capacitor Cr. The inductor L is electrically connected to the inverter circuit 1 through the DC blocking capacitor Cr. When the PWM-driven MOSFET is turned on, the on-state voltage drop of the MOSFET is ignored, and the voltage across the inductor remains constant. When the PWM-driven MOSFET is turned off, the inductor current forms a loop through the diode VD1, and the inductor current decreases linearly. Therefore, when the duty cycle D > 0.5, Vout > Vin, and the BOOST circuit behaves as a boost circuit. When the duty cycle D < 0.5, Vout < Vin, and the BOOST circuit behaves as a buck circuit. It has the advantages of high efficiency, simple control, and buck-boost capabilities.

[0025] Furthermore, such as Figure 2As shown, inverter circuit 1 includes main switching transistors T1, T2, T3, and T4. Main switching transistors T1 and T2 are electrically connected to a DC blocking capacitor Cr, and main switching transistors T3 and T4 are electrically connected to the transformer magnetizing inductance Lm. Main switching transistors T1 and T2 are connected in series, and capacitor C1 is connected in parallel between main switching transistors T3 and T4 after they are connected in series. Switching losses and conduction losses are greatly affected by the finite bipolar pulse width modulation (PWM) strategy; therefore, two modulation methods are adopted: finite bipolar PWM modulation and full-bridge phase-shift modulation. The finite bipolar PWM modulation strategy uses the lower transistors, i.e., main switching transistors T2 and T4, for PWM modulation, while the upper transistors are sequentially turned on according to half of the switching cycle. The full-bridge phase-shift modulation uses the left half-bridge main switching transistors T1 and T2... Using the bridge as a reference, the control timing of the right half-bridge is phase-shifted relative to the left half-bridge to control the output voltage. The duty cycles of the main switching transistors T1 and T3 are both 0.5, and they are turned on alternately in sequence.

[0026] When the main switch T1 is turned on, the main switches T2 and T3 are turned off, and the main switch T4 adjusts the output voltage by adjusting the duty cycle.

[0027] When the main switch T3 is turned on, the main switches T1 and T4 are turned off. The main switch T2 adjusts the output voltage by adjusting the duty cycle. Compared with the traditional bipolar control method, the finite bipolar control only adjusts the duty cycle of one switch each time it is turned on, which can more easily achieve soft switching operation.

[0028] Furthermore, such as Figure 2 and Figure 3 As shown, rectifier circuit 3 includes diodes VD2 and VD3. The middle part of transformer Tr is electrically connected to filter circuit 4. Filter circuit 4 includes transistor VT1. The base (b) pin of transistor VT1 is grounded through capacitor C3. A capacitor C4 and a resistor R2 are connected in parallel on the emitter (e) pin of transistor VT1. A resistor R1 and a diode VD4 are connected in series on the collector (c) pin of transistor VT1. After diode VD4 is connected between the base of transistor VT1 and ground, the input voltage reverse-biases diode VD4 through resistor R1. At this time, diode VD4... The voltage regulation characteristics of the transistor VT1 stabilize the base voltage, thus making the DC output voltage from the emitter of VT1 relatively stable. Resistor R1 also serves as the current-limiting protection resistor for diode VD4. After adding the Zener diode VD4, changing the value of resistor R1 does not change the magnitude of the emitter output voltage of transistor VT1. Due to the PN junction voltage drop at the emitter junction of transistor VT1, the emitter output voltage is slightly smaller than the regulated voltage of diode VD4. Capacitor C4, resistor R1, and transistor VT1 together form an electronic filter circuit, which serves as a filter.

[0029] like Figures 1-3 As shown in the figure, the principle of the DC-DC switching power supply control circuit based on the phase-shifted full-bridge converter provided in this embodiment is as follows:

[0030] The full-bridge DC-DC converter is a DC-DC conversion circuit suitable for high-power switching power supplies. It consists of an inverter circuit 1, a resonant circuit 2, a rectifier circuit 3, and a filter circuit 4. It is easy to achieve high frequency and has a simple main circuit structure. By adding resonant components such as small inductors and capacitors, resonant conditions are introduced before and after the switching process to achieve soft switching. It benefits from its advantages such as high output power, high efficiency, simple control, and electrical isolation.

[0031] When the PWM-driven MOSFET is turned on, the on-state voltage drop of the MOSFET is ignored, and the voltage across the inductor remains constant. When the PWM-driven MOSFET is turned off, the inductor current forms a loop through diode VD1, and the inductor current decreases linearly. Therefore, when the duty cycle D > 0.5, Vout > Vin, and the BOOST circuit behaves as a boost circuit. When the duty cycle D < 0.5, Vout < Vin, and the BOOST circuit behaves as a buck circuit. It has the advantages of high efficiency, simple control, and buck-boost capabilities.

[0032] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0033] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes that element.

[0034] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter, comprising an inverter circuit (1), a resonant circuit (2), a rectifier circuit (3), and a filter circuit (4) electrically connected, characterized in that, The resonant circuit (2) is electrically connected to the rectifier circuit (3) through the transformer Tr. The transformer Tr is provided with a transformer magnetizing inductor Lm in parallel and a transformer leakage inductance Lr and a DC blocking capacitor Cr in series. A boost circuit (5) is electrically connected between the transformer leakage inductance Lr and the DC blocking capacitor Cr. The boost circuit (5) includes a diode VD1 and a MOSFET T5. The diode VD1 is electrically connected between the transformer leakage inductance Lr and the DC blocking capacitor Cr. A capacitor C2 and a resistor RL are connected in parallel on the MOSFET T5.

2. The DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter according to claim 1, characterized in that: An inductor L is electrically connected between the diode VD1 and the DC blocking capacitor Cr, and the inductor L is electrically connected to the inverter circuit (1) through the DC blocking capacitor Cr.

3. The DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter according to claim 1, characterized in that: The inverter circuit (1) includes main switch transistors T1, T2, T3, and T4. Main switch transistors T1 and T2 are electrically connected to the DC blocking capacitor Cr, and main switch transistors T3 and T4 are electrically connected to the transformer magnetizing inductance Lm.

4. The DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter according to claim 3, characterized in that: The main switch transistors T1 and T2 are connected in series, and the main switch transistors T3 and T4 are connected in series and then a capacitor C1 is connected in parallel.

5. The DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter according to claim 1, characterized in that: The rectifier circuit (3) includes diodes VD2 and VD3, and the middle part of the transformer Tr is electrically connected to the filter circuit (4).

6. The DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter according to claim 1, characterized in that: The filter circuit (4) includes a transistor VT1. The base pin of the transistor VT1 is grounded through a capacitor C3. A capacitor C4 and a resistor R2 are connected in parallel on the emitter pin of the transistor VT1.

7. The DC-DC switching power supply control circuit based on a phase-shifted full-bridge converter according to claim 6, characterized in that: A resistor R1 and a diode VD4 are connected in series on the collector pin of the transistor VT1.

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