Step-down circuit and power supply device

Abstract

The present application provides a step-down circuit and a power supply device, wherein the step-down circuit includes a voltage input port, a voltage output port, two step-down units and a gating unit. The step-down circuit includes a charging stage and a discharging stage; in the charging stage, the gating unit connects the capacitors and inductors in the two step-down units to the voltage input port and the voltage output port in a first connection mode, and in the first connection mode, the power supply voltage input by the voltage input port charges the capacitors and inductors of at least one step-down unit, and outputs to the voltage output port at the same time; in the discharging stage, the gating unit connects the capacitors and inductors in the two step-down units to the voltage input port and the voltage output port in a second connection mode, and in the second connection mode, the capacitors and inductors of at least one step-down unit discharge and output to the voltage output port. The present application can effectively improve the step-down capability and conversion efficiency of the step-down circuit.

Description

Technical Field

[0001] The present application relates to the technical field of power electronic conversion, and in particular to a step-down circuit and a power supply device having the step-down circuit. Background Art

[0002] At present, various types of power electronic conversion circuits are widely used in various fields. According to their topological structures, they can be divided into buck circuits (BUCK), boost circuits (BOOST), and buck-boost circuits (BUCK-BOOST). Among them, with the development of the economy and society, many electrical equipment requires low-voltage, high-current power supply equipment, so the AC mains power is usually directly rectified and passed through a buck circuit with high buck capability to meet the application requirements, and requires a higher conversion efficiency. Therefore, how to effectively improve the buck capability and conversion efficiency of the buck circuit has become a problem that needs to be considered. Summary of the invention

[0003] The present application provides a step-down circuit and a power supply device, which can effectively improve the step-down capability and conversion efficiency of the step-down circuit.

[0004] In a first aspect, a buck circuit is provided, the buck circuit comprising a voltage input port, a voltage output port, two buck units and a gating unit. The voltage input port is used to input the power supply voltage; the two step-down units are connected between the voltage input port and the voltage output port, each of the step-down units includes a capacitor and an inductor, and the connection relationship of the capacitor and / or inductor in each step-down unit is adjustable; the gating unit is used to adjust the connection relationship of the capacitor and / or inductor in the two step-down units; wherein the step-down circuit includes a charging stage and a discharging stage; in the charging stage, the gating unit connects the capacitor and inductor in the two step-down units with the voltage input port and the voltage output port in a first connection mode, and in the first connection mode, the power supply voltage input by the voltage input port charges the capacitor and inductor of the at least one step-down unit and outputs to the voltage output port at the same time; in the discharging stage, the gating unit connects the capacitor and inductor in the two step-down units with the voltage input port and the voltage output port in a second connection mode, and in the second connection mode, the capacitor and inductor of the at least one step-down unit discharge and output to the voltage output port.

[0005] In a possible implementation, the two step-down units include a first step-down unit and a second step-down unit: the first step-down unit includes a first capacitor and a first inductor, the first capacitor is connected in series with the first inductor, and the end of the first capacitor not connected to the first inductor can be selectively connected to the voltage input port or the voltage output port, and the end of the first inductor not connected to the first capacitor can be selectively connected to the voltage output port; the second step-down unit includes a second capacitor and a second inductor, the second capacitor and the second inductor are sequentially connected in series between the end of the first inductor not connected to the first capacitor and the voltage output port, and the end of the second capacitor connected to the first inductor can also be selectively connected to the voltage output port; the gating unit is used to connect the first capacitor to the voltage input port or the voltage output port, and to connect the first inductor, the second capacitor and the second inductor to the voltage output port. wherein, in the charging stage, the gating unit connects the first capacitor to the voltage input port, and disconnects the first inductor and the second capacitor from the voltage output port, so that the first step-down unit and the second step-down unit are in the first connection mode as a whole, and the power supply voltage input by the voltage input port charges the first capacitor, the first inductor, the second capacitor and the second inductor, and outputs to the voltage output port at the same time; in the discharging stage, the gating unit disconnects the first capacitor from the voltage input port, and connects the first capacitor, the first inductor and the second capacitor to the voltage output port, so that the first step-down unit and the second step-down unit are in the second connection mode as a whole, and the first capacitor, the first inductor, the second capacitor and the second inductor discharge and output to the voltage output port.

[0006] In a possible implementation, the voltage input port includes a positive input terminal and a negative input terminal, the voltage output port includes a positive output terminal and a negative output terminal, the negative input terminal is connected to the negative output terminal, and the positive input terminal is used to input a power supply voltage; the second capacitor and the second inductor are sequentially connected in series between an end of the first inductor that is not connected to the first capacitor and the positive output terminal, and the end of the first capacitor that is not connected to the first inductor can be selectively connected to the positive input terminal or the positive output terminal, and the end of the first inductor that is not connected to the first capacitor and the end of the second capacitor that is connected to the first inductor are connected in series with each other. The positive output terminal can be selectively connected to one end of the first capacitor connected to the first inductor, one end of the first inductor connected to the first capacitor, one end of the second capacitor not connected to the first inductor, and one end of the second inductor connected to the second capacitor and can be selectively connected to the negative output terminal; wherein the gating unit is used to connect the first capacitor to the positive input terminal or the positive output terminal, and connect or disconnect the first inductor and the second capacitor to the positive output terminal, and connect or disconnect the first capacitor, the first inductor, the second capacitor, and the second inductor to the negative output terminal.

[0007] In a possible implementation, the gating unit includes a first switch, a second switch, a first diode, a second diode, and a third diode, wherein the first switch is connected between the positive input terminal and the end of the first capacitor that is not connected to the first inductor, the second switch is connected between the end of the first capacitor that is not connected to the first inductor and the end of the second inductor that is not connected to the first capacitor, the positive electrode of the first diode is connected to the connection point between the second capacitor and the second inductor, the negative electrode of the first diode is connected to the connection point between the first capacitor and the first inductor, the positive electrode of the second diode is connected to the connection point between the first inductor and the second capacitor, the negative electrode of the second diode is connected to the connection point between the first capacitor and the second switch, and the positive electrode of the third diode is connected to the negative input terminal. The cathode of the third diode is connected to the connection point between the second capacitor and the second inductor; wherein the first switch and the second switch are complementary turned on or off at a certain duty cycle, the first diode, the second diode and the third diode are unidirectional conducting diodes, and are turned on or off according to the current flow, the first switch, the second switch, the first diode, the second diode and the third diode cooperate to connect the first capacitor to the positive input terminal or the positive output terminal, and connect or disconnect the first inductor and the second capacitor to the positive output terminal, and connect or disconnect the first capacitor, the first inductor, the second capacitor and the second inductor to the negative output terminal, so as to switch the charging state or the discharging state of the buck circuit.

[0008] In a possible implementation, in the charging stage, the first switch is turned on, the second switch is turned off, the first diode, the second diode and the third diode are all turned off, and the first capacitor is connected to the positive input terminal through the turned-on first switch; in the discharging stage, the first switch is turned off, the second switch is turned on, the first diode, the second diode and the third diode are all turned on, the first capacitor, the first inductor, the second capacitor and the second inductor are connected to the positive output terminal through the turned-on second switch and the second diode, and the first capacitor, the first inductor, the second capacitor and the second inductor are connected to the negative output terminal through the turned-on first diode and the third diode.

[0009] In a possible implementation, the buck circuit further includes a control unit, which is used to output a corresponding control signal to control the first switch and the second switch to be turned on or off, and to control the on-duty cycle of the first switch and the second switch by adjusting the duty cycle of the corresponding control signal.

[0010] In a possible implementation, the step-down circuit further includes an output capacitor, one end of the output capacitor is connected to the positive output terminal, and the other end of the output capacitor is connected to the negative output terminal; wherein, in the charging stage, the power supply voltage input to the positive input terminal also charges the output capacitor; and in the discharging stage, the positive output terminal is also output through the output capacitor.

[0011] In a possible implementation manner, the output voltage of the voltage output port, the voltage difference across the first capacitor, and the voltage difference across the second capacitor are all equal.

[0012] In a possible implementation manner, the voltage input port is a DC voltage input port, and the voltage output port is a DC voltage output port.

[0013] In a second aspect, a power supply device is further provided, the power supply device comprising a step-down circuit. The step-down circuit comprises a voltage input port, a voltage output port, two step-down units and a gating unit. The voltage input port is used to input the power supply voltage; the two step-down units are connected between the voltage input port and the voltage output port, each of the step-down units includes a capacitor and an inductor, and the connection relationship of the capacitor and / or inductor in each step-down unit is adjustable; the gating unit is used to adjust the connection relationship of the capacitor and / or inductor in the two step-down units; wherein the step-down circuit includes a charging stage and a discharging stage; in the charging stage, the gating unit connects the capacitor and inductor in the two step-down units with the voltage input port and the voltage output port in a first connection mode, and in the first connection mode, the power supply voltage input by the voltage input port charges the capacitor and inductor of the at least one step-down unit and outputs to the voltage output port at the same time; in the discharging stage, the gating unit connects the capacitor and inductor in the two step-down units with the voltage input port and the voltage output port in a second connection mode, and in the second connection mode, the capacitor and inductor of the at least one step-down unit discharge and output to the voltage output port.

[0014] The step-down circuit and power supply device of the present application can adjust the connection relationship of the capacitor and / or inductor in each of the step-down units, and adjust the connection relationship of the capacitors and / or inductors in the two step-down units by setting a selection unit. While having a higher conversion efficiency, the step-down capability of the step-down circuit can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0016] Figure 1 FIG. 4 is a circuit diagram of a voltage-reducing circuit in an embodiment of the present application.

[0017] Figure 2 For Figure 1 The schematic diagram of the buck circuit shown is in the charging stage.

[0018] Figure 3 For Figure 1 The circuit diagram of the buck circuit shown is in the discharge stage.

[0019] Figure 4 The step-down circuit in one embodiment of the present application further includes a circuit diagram of a control unit.

[0020] Figure 5 is a waveform diagram of the on-duty cycle of the first switch and the step-down ratio of the step-down circuit.

[0021] Figure 6 Schematic diagram of waveforms of the output voltage, the first capacitor voltage and the second capacitor voltage when the on-duty cycle of the first switch is 0.5.

[0022] Figure 7 Schematic diagram of waveforms of the output voltage, the first capacitor voltage and the second capacitor voltage when the on-duty cycle of the first switch is 0.3.

[0023] Figure 8 FIG. 4 is a circuit diagram of a voltage-reducing circuit in another embodiment of the present application.

[0024] Fig. 9 It is a block diagram of a power supply device in an embodiment of the present application.

[0025] Explanation of the reference numerals: 100, buck circuit, 10, voltage input port, Vin, power supply voltage, Vin+, positive input terminal, Vin-, negative input terminal, 20, voltage output port, Vo, output voltage, Vout+, positive output terminal, Vout-, negative output terminal, 30, first buck unit, L1, first inductor, C1, first capacitor, Vc1, first capacitor voltage, 40, second buck unit, L2, second inductor, C2, second capacitor, Vc2, second capacitor voltage, 50, selection unit, S1, first switch, S2, second switch, D1, first diode, D2, second diode, D3, third diode, Co, output capacitor, 60, control unit, 1000, power supply device. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0028] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0029] In the description of the embodiments of the present application, it should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0030] In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0031] See also Figure 1 , Figure 1 FIG. 1 is a circuit diagram of a voltage-reducing circuit in an embodiment of the present application. Figure 1 As shown, the present application provides a buck circuit 100 , which includes a voltage input port 10 , a voltage output port 20 , two buck units and a gating unit 50 . The voltage input port 10 is used to input the power supply voltage Vin; two step-down units are connected between the voltage input port 10 and the voltage output port 20, each step-down unit includes a capacitor and an inductor, and the connection relationship of the capacitor and / or inductor in each step-down unit is adjustable; the gating unit 50 is used to adjust the connection relationship of the capacitor and / or inductor in the two step-down units; wherein the step-down circuit 100 includes a charging stage and a discharging stage; in the charging stage, the gating unit 50 connects the capacitor and inductor in the two step-down units with the voltage input port 10 and the voltage output port 20 in a first connection mode, under which the power supply voltage Vin input by the voltage input port 10 charges the capacitor and inductor of at least one step-down unit and outputs to the voltage output port 20 at the same time; in the discharging stage, the gating unit 50 connects the capacitor and inductor in the two step-down units with the voltage input port 10 and the voltage output port 20 in a second connection mode, under which the capacitor and inductor of at least one step-down unit discharge and output to the voltage output port 20.

[0032] Therefore, the above-mentioned buck circuit 100 in the present application can be adjusted by setting the connection relationship of the capacitor and / or inductor in each buck unit, and the connection relationship of the capacitor and / or inductor in the two buck units is adjusted by setting the selection unit 50, which can effectively improve the buck capability of the buck circuit 100 while having a higher conversion efficiency.

[0033] like Figure 1As shown, the two step-down units include a first step-down unit 30 and a second step-down unit 40: the first step-down unit 30 includes a first capacitor C1 and a first inductor L1, the first capacitor C1 is connected in series with the first inductor L1, and the end of the first capacitor C1 not connected to the first inductor L1 can be selectively connected to the voltage input port 10 or the voltage output port 20, and the end of the first inductor L1 not connected to the first capacitor C1 can be selectively connected to the voltage output port 20; the second step-down unit 40 includes a second capacitor C2 and a second inductor L2, the second capacitor C2 and the second inductor L2 are sequentially connected in series between the end of the first inductor L1 not connected to the first capacitor C1 and the voltage output port 20, and the end of the second capacitor C2 connected to the first inductor L1 can also be selectively connected to the voltage output port 20; the gating unit 50 is used to connect the first capacitor C1 to the voltage input port 10 or the voltage output port 20, and to connect the first inductor L1 and the second capacitor C2 to the voltage output port 20. 2 is connected or disconnected with the voltage output port 20; wherein, in the charging stage, the gating unit 50 connects the first capacitor C1 with the voltage input port 10, and disconnects the first inductor L1 and the second capacitor C2 with the voltage output port 20, so that the first step-down unit 30 and the second step-down unit 40 are in the first connection mode as a whole, and the power supply voltage Vin input by the voltage input port 10 charges the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2, and outputs to the voltage output port 20 at the same time; in the discharging stage, the gating unit 50 disconnects the first capacitor C1 from the voltage input port 10, and connects the first capacitor C1, the first inductor L1 and the second capacitor C2 with the voltage output port 20, so that the first step-down unit 30 and the second step-down unit 40 are in the second connection mode as a whole, and the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 discharge and output to the voltage output port 20.

[0034] Thus, the above-mentioned buck circuit 100 in the present application, by setting the first capacitor C1 of the first buck unit 30 to be connected in series with the first inductor L1, and the end of the first capacitor C1 not connected to the first inductor L1 can be selectively connected to the voltage input port 10 or the voltage output port 20, the end of the first inductor L1 not connected to the first capacitor C1 can be selectively connected to the voltage output port 20, and by setting the second capacitor C2 of the second buck unit 40 and the second inductor L2 to be connected in series between the end of the first inductor L1 not connected to the first capacitor C1 and the voltage output port 20 in sequence, and the end of the second capacitor C2 connected to the first inductor L1 can also be selectively connected to the voltage output port 20, and by setting the gating unit 50 to switch the corresponding connection relationship, the buck capability of the buck circuit 100 can be effectively improved while having a higher conversion efficiency.

[0035] Specifically, compared with a two-stage or even multi-stage power conversion circuit, the buck circuit 100 of the present application is a single-stage power conversion circuit, which can have a higher conversion efficiency while ensuring a buck effect.

[0036] like Figure 1 As shown, the voltage input port 10 includes a positive input terminal Vin+ and a negative input terminal Vin-, and the voltage output port 20 includes a positive output terminal Vout+ and a negative output terminal Vout-, the negative input terminal Vin- is connected to the negative output terminal Vout-, and the positive input terminal Vin+ is used to input the power supply voltage Vin; the second capacitor C2 and the second inductor L2 are sequentially connected in series between the end of the first inductor L1 that is not connected to the first capacitor C1 and the positive output terminal Vout+, and the end of the first capacitor C1 that is not connected to the first inductor L1 can be selectively connected to the positive input terminal Vin+ or the positive output terminal Vout+, the end of the first inductor L1 that is not connected to the first capacitor C1, the end of the second capacitor C2 that is connected to the first inductor L1 One end connected to the positive output terminal Vout+ is selectively connected, one end of the first capacitor C1 connected to the first inductor L1, one end of the first inductor L1 connected to the first capacitor C1, one end of the second capacitor C2 not connected to the first inductor L1, and one end of the second inductor L2 connected to the second capacitor C2 are selectively connected to the negative output terminal Vout-; wherein, the gating unit 50 is used to connect the first capacitor C1 to the positive input terminal Vin+ or the positive output terminal Vout+, and connect or disconnect the first inductor L1 and the second capacitor C2 to the positive output terminal Vout+, and connect or disconnect the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 to the negative output terminal Vout-.

[0037] Thus, the above-mentioned buck circuit 100 in the present application, through the above connection relationship and the selection unit 50, can connect the first capacitor C1 to the positive input terminal Vin+ or the positive output terminal Vout+, and connect or disconnect the first inductor L1 and the second capacitor C2 to the positive output terminal Vout+, and connect or disconnect the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 to the negative output terminal Vout-, so as to have a higher conversion efficiency and ensure the buck effect at the same time.

[0038] In one or more embodiments, the power supply voltage Vin input to the voltage input port 10 is the voltage difference between the positive input terminal Vin+ and the negative input terminal Vin-, and the output voltage Vo of the voltage output port 20 is the voltage difference between the positive output terminal Vout+ and the negative output terminal Vout-.

[0039] Please also read Figure 2 , Figure 3 , Figure 2 For Figure 1 The circuit diagram of the buck circuit in the charging stage is shown in FIG. Figure 3 For Figure 1 The circuit diagram of the buck circuit in the discharge stage is shown in FIG. Figure 2 , Figure 3 As shown, the gating unit 50 includes a first switch S1, a second switch S2, a first diode D1, a second diode D2 and a third diode D3. The first switch S1 is connected between the positive input terminal Vin+ and the end of the first capacitor C1 that is not connected to the first inductor L1, the second switch S2 is connected between the end of the first capacitor C1 that is not connected to the first inductor L1 and the end of the second inductor L2 that is not connected to the first capacitor C1, the positive electrode of the first diode D1 is connected to the connection point between the second capacitor C2 and the second inductor L2, the negative electrode of the first diode D1 is connected to the connection point between the first capacitor C1 and the first inductor L1, the positive electrode of the second diode D2 is connected to the connection point between the first inductor L1 and the second capacitor C2, the negative electrode of the second diode D2 is connected to the connection point between the first capacitor C1 and the second switch S2, and the positive electrode of the third diode D3 is connected to the negative input terminal Vin- and the negative The cathode of the third diode D3 is connected to the connection point between the positive input terminal Vin+ and the positive output terminal Vout-, and the cathode of the third diode D3 is connected to the connection point between the second capacitor C2 and the second inductor L2; wherein the first switch S1 and the second switch S2 are complementary turned on or off at a certain duty cycle, the first diode D1, the second diode D2 and the third diode D3 are unidirectional conducting diodes, and according to the current flow, the first switch S1, the second switch S2, the first diode D1, the second diode D2 and the third diode D3 cooperate to connect the first capacitor C1 to the positive input terminal Vin+ or the positive output terminal Vout+, and connect or disconnect the first inductor L1 and the second capacitor C2 to the positive output terminal Vout+, and connect or disconnect the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 to the negative output terminal Vout-, so as to switch the charging state or the discharging state of the buck circuit 100.

[0040] Thus, the buck circuit 100 in the present application sets the first switch S1, the second switch S2, the first diode D1, the second diode D2 and the third diode D3 of the selection unit 50 and the corresponding connection relationship, and configures the first switch S1 and the second switch S2 to be complementary turned on or off at a certain duty cycle. The first diode D1, the second diode D2 and the third diode D3 are unidirectional conducting diodes, which are turned on or off according to the current flow. The first switch S1, the second switch S2, the first diode D1, the second diode D2 and the third diode D3 can cooperate to connect the first capacitor C1 to the positive input terminal Vin+ or the positive output terminal Vout+, connect or disconnect the first inductor L1 and the second capacitor C2 to the positive output terminal Vout+, and connect or disconnect the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 to the negative output terminal Vout-, so as to switch the charging state or the discharging state of the buck circuit 100.

[0041] In one or more embodiments, the first switch S1 and the second switch S2 may be a power field effect transistor (Metal Oxide Semiconductor FET, MOSFET), an insulated gate bipolar transistor (Insulate-Gate Bipolar Transistor, IGBT) or other controllable switch devices. When the first switch S1 and the second switch S2 are both MOSFETs, the first switch S1 and the second switch S2 may be N-type MOSFETs or P-type MOSFETs. The first switch S1 and the second switch S2 are turned on or off complementarily with a certain duty cycle, that is, the switching cycle and the switching frequency of the first switch S1 and the second switch S2 are the same, and the on-duty cycle is complementary, so they can be turned on or off complementarily.

[0042] In one or more embodiments, the first diode D1, the second diode D2, and the third diode D3 may be various types of common diodes, or may be various types of Zener diodes (ZD), Schottky Barrier Diodes (SBD), Fast Recovery Diodes (FRD), Transient Voltage Suppressors (TVS), or other diodes with unidirectional conduction characteristics. Wherein, when the current flowing through the first diode D1 flows in the same direction as the unidirectional conduction direction of the first diode D1, the first diode D1 is turned on, and when the current flows in the opposite direction to the unidirectional conduction direction of the first diode D1, the first diode D1 is turned off. When the current flows in the same direction as the unidirectional conduction direction of the second diode D2, the second diode D2 is turned on, and when the current flows in the opposite direction to the unidirectional conduction direction of the second diode D2, the second diode D2 is turned off. When the current flows in the same direction as the unidirectional conduction direction of the third diode D3 , the third diode D3 is turned on, and when the current flows in the opposite direction to the unidirectional conduction direction of the third diode D3 , the third diode D3 is turned off.

[0043] like Figure 2 , Figure 3 As shown, in the charging stage, the first switch S1 is turned on, the second switch S2 is turned off, the first diode D1, the second diode D2 and the third diode D3 are all turned off, and the first capacitor C1 is connected to the positive input terminal Vin+ through the turned-on first switch S1; in the discharging stage, the first switch S1 is turned off, the second switch S2 is turned on, the first diode D1, the second diode D2 and the third diode D3 are all turned on, the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 are connected to the positive output terminal Vout+ through the turned-on second switch S2 and the second diode D2, and the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 are connected to the negative output terminal Vout- through the turned-on first diode D1 and the third diode D3.

[0044] Thus, in the above-mentioned buck circuit 100 in the present application, in the charging stage, by configuring the first switch S1 to be turned on, the branch where the first switch S1 is located is also turned on, the second switch S2 is turned off, the branch where the second switch S2 is located is also turned off, and the conduction direction of the first diode D1, the second diode D2 and the third diode D3 is opposite to the current flow direction flowing through them, then the first diode D1, the second diode D2 and the third diode D3 are all turned off, and the branch where the first diode D1, the second diode D2 and the third diode D3 are located is also turned off, so that the first capacitor C1 is connected to the positive input terminal Vin+ through the turned-on first switch S1. In the discharge stage, by configuring the first switch S1 to be disconnected, the branch where the first switch S1 is located is also disconnected, the second switch S2 is turned on, the branch where the second switch S2 is located is also turned on, and the conduction directions of the first diode D1, the second diode D2 and the third diode D3 are the same as the current flowing through them, then the first diode D1, the second diode D2 and the third diode D3 are all turned on, and the branch where the first diode D1, the second diode D2 and the third diode D3 are located is also turned on, so that the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 are connected to the positive output terminal Vout+ through the turned-on second switch S2 and the second diode D2, and the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 are connected to the negative output terminal Vout- through the turned-on first diode D1 and the third diode D3.

[0045] Specifically, Figure 2 As shown, in the charging stage, the first switch S1 is turned on and the second switch S2 is turned off. The current of the buck circuit 100 flows from the positive input terminal Vin+, the first switch S1, the first capacitor C1, the first inductor L1, the second capacitor C2, the second inductor L2, the positive output terminal Vout+, the negative output terminal Vout-, the negative input terminal Vin- back to the positive input terminal Vin+ to form a current loop in the charging stage. The conduction direction of the first diode D1, the second diode D2 and the third diode D3 is opposite to the current flow direction flowing through them, so the first diode D1, the second diode D2 and the third diode D3 are all turned off, and the branch where the first diode D1, the second diode D2 and the third diode D3 are located is also turned off. The power supply voltage Vin input at the positive input terminal Vin+ of the voltage input port 10 charges the first capacitor C1, the first inductor L1, the second capacitor C2 and the second inductor L2 through the current loop in the charging stage, and outputs to the positive output terminal Vout+ of the voltage output port 20 at the same time. Figure 3As shown, in the discharge stage, the first switch S1 is turned off and the second switch S2 is turned on. The current of the buck circuit 100 flows to the first capacitor C1, the second switch S2, the positive output terminal Vout+, the negative output terminal Vout-, the third diode D3, the first diode D1 back to the first capacitor C1, and flows to the first inductor L1, the second diode D2, the second switch S2, the positive output terminal Vout+, the negative output terminal Vout-, the third diode D3, the first diode D1 back to the first inductor L1, and flows to the second capacitor C2, the second diode D2, the second switch S2, the positive output terminal Vout+, the negative output terminal Vout-, the third diode D3, the first diode D1 back to the first inductor L1. The diode D3 returns to the second capacitor C2, and is the second inductor L2, the positive output terminal Vout+, the negative output terminal Vout-, and the third diode D3 returns to the second inductor L2. The conduction direction of the first diode D1, the second diode D2, and the third diode D3 are the same as the current flowing through them, then the first diode D1, the second diode D2, and the third diode D3 are all turned on, and the branch where the first diode D1, the second diode D2, and the third diode D3 are located is also turned on, and the first capacitor C1, the first inductor L1, the second capacitor C2, and the second inductor L2 discharge and output the positive output terminal Vout+ of the voltage output port 20.

[0046] See also Figure 4 , Figure 4 FIG. 1 is a circuit diagram of a voltage reduction circuit in an embodiment of the present application, which further includes a control unit. Figure 4 As shown, the buck circuit 100 also includes a control unit 60, which is used to output a corresponding control signal to control the first switch S1 and the second switch S2 to be turned on or off, and to control the on-duty cycle of the first switch S1 and the second switch S2 by adjusting the duty cycle of the corresponding control signal.

[0047] Therefore, the above-mentioned buck circuit 100 in the present application, by setting a control unit 60, and configuring the control unit 60 to output a corresponding control signal to control the first switch S1 and the second switch S2 to be turned on or off, and configuring the control unit 60 to adjust the duty cycle of the corresponding control signal to control the on-duty cycle of the first switch S1 and the second switch S2.

[0048] In one or more embodiments, the control unit 60 can be a general-purpose processor such as a central processing unit (CPU), or a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate logic devices, transistor logic devices and other logic control devices, or a microprocessor such as a micro control unit (MCU).

[0049] In one or more embodiments, the corresponding control signal may be a pulse width modulation signal (PWM). By adjusting the pulse width of the pulse width modulation signal, the duty cycle of the corresponding control signal may be adjusted to control and adjust the conduction duty cycle of the first switch S1 and the second switch S2.

[0050] Please refer again Figure 1-Figure 4 .like Figure 1-Figure 4 As shown, the buck circuit 100 also includes an output capacitor Co, one end of the output capacitor Co is connected to the positive output terminal Vout+, and the other end of the output capacitor Co is connected to the negative output terminal Vout-; wherein, in the charging stage, the power supply voltage Vin inputted from the positive input terminal Vin+ also charges the output capacitor Co; in the discharging stage, the positive output terminal Vout+ is also outputted through the output capacitor Co.

[0051] Therefore, the above-mentioned buck circuit 100 in the present application is connected to the positive output terminal Vout+ through one end of the output capacitor Co, and the other end of the output capacitor Co is connected to the negative output terminal Vout-. In the charging stage, the power supply voltage Vin input at the positive input terminal Vin+ can also charge the output capacitor Co; in the discharging stage, the positive output terminal Vout+ is also output through the output capacitor Co to improve the output stability of the positive output terminal Vout+ of the voltage output port 20.

[0052] See also Figure 5 , Figure 5 Schematic diagram of waveforms of the on-duty cycle of the first switch and the step-down ratio of the step-down circuit. Figure 5 As shown, the on-duty cycle of the first switch S1 increases, and the step-down ratio of the buck circuit 100 increases, wherein the step-down ratio is the ratio of the power supply voltage Vin to the output voltage Vo.

[0053] Therefore, the buck circuit 100 in the present application can adjust the output voltage Vo of the buck circuit 100 by adjusting the on-duty cycle of the first switch S1 to meet the required voltage conversion requirements.

[0054] In one or more embodiments, the on-duty cycle of the first switch S1 is greater than 0.4, and the on-duty cycle of the second switch S2 is less than 0.6.

[0055] Therefore, in the above-mentioned buck circuit 100 in the present application, when the on-duty cycle of the first switch S1 is greater than 0.4, the buck ratio of the buck circuit 100 is significantly increased, and is greater than the buck ratio that can be achieved by two-stage or even multi-stage power conversion circuits or other conventional circuits, and the buck circuit 100 has a stronger buck capability.

[0056] Please also read Figure 6 , Figure 7 , Figure 6 is a waveform diagram of the output voltage, the first capacitor voltage and the second capacitor voltage when the on-duty ratio of the first switch is 0.5, Figure 7 Schematic diagram of waveforms of the output voltage, the first capacitor voltage, and the second capacitor voltage when the on-duty ratio of the first switch is 0.3. Figure 6 , Figure 7 As shown, the output voltage Vo of the voltage output port 20, the voltage difference across the first capacitor C1, and the voltage difference across the second capacitor C2 are all equal.

[0057] Therefore, the above-mentioned buck circuit 100 in the present application, according to the volt-second balance principle satisfied by the first inductor L1 and the second inductor L2 during stable operation, can deduce that the output voltage Vo, the first capacitor voltage Vc1 and the second capacitor voltage Vc2 are equal, and satisfy the following relationship expression: Vo=Vc1=Vc2=Vin×d / (2+d), where d is the on-duty cycle of the first switch S1.

[0058] like Figure 6 , Figure 7 As shown, when the power supply voltage Vin is 500 volts (V), the first inductor L1 and the second inductor L2 are both 11 microhenries (μH), the first capacitor C1 and the second capacitor C2 are both 22 microfarads (μF), the output capacitor Co is 100 μF, the load connected to the voltage output port 20 is 1 ohm (Ω), the frequency of the control signal is 100 kilohertz (kHz), and the on-duty cycle of the first switch S1 is set to 0.5 and 0.3, as shown in FIG. Figure 6 , Figure 7As shown, it can be seen that after the buck circuit 100 is stabilized, the output voltage Vo, the first capacitor voltage Vc1 and the second capacitor voltage Vc2 are all about 100V and 65V, which effectively verifies that the buck circuit 100 can effectively reduce the output voltage Vo while having a high conversion efficiency.

[0059] Specifically, the first capacitor voltage Vc1 is the voltage difference across the first capacitor C1, that is, the first capacitor voltage Vc1 is the voltage at the high voltage end of the first capacitor C1 minus the voltage at the low voltage end of the first capacitor C1, or is the absolute value of the voltage difference across the first capacitor C1. The second capacitor voltage Vc2 is the voltage difference across the second capacitor C2, that is, the second capacitor voltage Vc2 is the voltage at the high voltage end of the second capacitor C2 minus the voltage at the low voltage end of the second capacitor C2, or is the absolute value of the voltage difference across the second capacitor C2.

[0060] In one or more embodiments, the voltage input port 10 is a DC voltage input port 10 , and the voltage output port 20 is a DC voltage output port 20 .

[0061] Therefore, the above-mentioned step-down circuit 100 in the present application can convert the DC voltage to output a stepped-down DC voltage to meet the required voltage conversion requirements.

[0062] See also Figure 8 , Figure 8 FIG. 1 is a circuit diagram of a voltage-reducing circuit in another embodiment of the present application. Figure 8As shown, the buck circuit 100 includes a voltage input port 10 , a voltage output port 20 , a first buck unit 30 , a second buck unit 40 and a gating unit 50 . The voltage input port 10 is used to input the power supply voltage Vin; the voltage output port 20 includes a positive output terminal Vout+ and a negative output terminal Vout-; the first step-down unit 30 includes a first inductor L1 and a first capacitor C1, the first inductor L1 is connected to the first capacitor C1, and the end of the first inductor L1 not connected to the first capacitor C1 is selectively connected to the voltage input port 10, and the end of the first capacitor C1 not connected to the first inductor L1 is connected to the positive output terminal Vout+; the second step-down unit 40 includes a second inductor L2 and a second capacitor C2, the second inductor L2 is connected to the second capacitor C2, and the second inductor L2 is selectively connected to the two ends of the first capacitor C1 or to the two ends of the first inductor L1 and the first capacitor C1 connected in series, and the second capacitor C2 is connected between the positive output terminal Vout+ and the negative output terminal Vout-; the gating unit 50 is used to connect or disconnect the first inductor L1 to the voltage input port 10, and connect the second inductor L2 to The two ends of the first capacitor C1 are connected to the two ends of the first inductor L1 and the first capacitor C1 connected in series; wherein, the buck circuit 100 includes a charging stage and a discharging stage; in the charging stage, the gating unit 50 connects the first inductor L1 to the voltage input port 10, and connects the second inductor L2 to the two ends of the first capacitor C1, the power supply voltage Vin input by the voltage input port 10 charges the first inductor L1, the first capacitor C1, the second inductor L2 and the second capacitor C2, and outputs to the voltage output port 20 at the same time; in the discharging stage, the gating unit 50 disconnects the first inductor L1 from the voltage input port 10, and connects the second inductor L2 to the two ends of the first inductor L1 and the first capacitor C1 connected in series, the first inductor L1 and the second inductor L2 are discharged, the first capacitor C1 and the second capacitor C2 are freewheeling, so as to output to the voltage output port 20; wherein, the output voltage Vo of the voltage output port 20 is equal to the voltage difference between the two ends of the second capacitor C2.

[0063] Thus, the above-mentioned buck circuit 100 in the present application is connected to the first capacitor C1 by setting the first inductor L1 of the first buck unit 30, and the end of the first inductor L1 not connected to the first capacitor C1 is selectively connected to the voltage input port 10, and the end of the first capacitor C1 not connected to the first inductor L1 is connected to the positive output terminal Vout+, and is connected to the second capacitor C2 by setting the second inductor L2 of the second buck unit 40, and the second inductor L2 is selectively connected to the two ends of the first capacitor C1 or to the two ends of the first inductor L1 and the first capacitor C1 connected in series, and the second capacitor C2 is connected between the positive output terminal Vout+ and the negative output terminal Vout-, and the corresponding connection relationship is switched by setting the selection unit 50, so that the voltage stress of the electronic components can be effectively reduced while having a higher buck capability.

[0064] The buck circuit 100 of the present application, through the above-mentioned structure, can effectively improve the buck capability of the buck circuit 100 while having a higher conversion efficiency. It also has advantages in both conversion efficiency and buck capability, has better application value, and can convert the DC voltage to output a stepped-down DC voltage to meet the required voltage conversion requirements.

[0065] See also Fig. 9 , Fig. 9 FIG. 1 is a block diagram of a power supply device in an embodiment of the present application. Fig. 9 As shown, the present application further provides a power supply device 1000, and the power supply device 1000 includes the buck circuit 100 in any of the aforementioned embodiments.

[0066] Please refer again Figure 1 .like Figure 1As shown, the buck circuit 100 includes a voltage input port 10 , a voltage output port 20 , two buck units and a gating unit 50 . The voltage input port 10 is used to input the power supply voltage Vin; two step-down units are connected between the voltage input port 10 and the voltage output port 20, each step-down unit includes a capacitor and an inductor, and the connection relationship of the capacitor and / or inductor in each step-down unit is adjustable; the gating unit 50 is used to adjust the connection relationship of the capacitor and / or inductor in the two step-down units; wherein the step-down circuit 100 includes a charging stage and a discharging stage; in the charging stage, the gating unit 50 connects the capacitor and inductor in the two step-down units with the voltage input port 10 and the voltage output port 20 in a first connection mode, under which the power supply voltage Vin input by the voltage input port 10 charges the capacitor and inductor of at least one step-down unit and outputs to the voltage output port 20 at the same time; in the discharging stage, the gating unit 50 connects the capacitor and inductor in the two step-down units with the voltage input port 10 and the voltage output port 20 in a second connection mode, under which the capacitor and inductor of at least one step-down unit discharge and output to the voltage output port 20.

[0067] The more specific structure of the buck circuit 100 can refer to the relevant content of the buck circuit 100 in any of the aforementioned embodiments, which will not be described in detail here.

[0068] The step-down circuit 100 and the power supply device 1000 of the present application, through the above-mentioned structure, can effectively improve the step-down capability of the step-down circuit 100 while having a higher conversion efficiency. They also have advantages in both conversion efficiency and step-down capability, have better application value, and can convert DC voltage to output a stepped-down DC voltage to meet the required voltage conversion requirements.

[0069] The above description is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application; in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A step-down circuit, characterized in that: include: Voltage input port, used to input power supply voltage; Voltage output port; Two step-down units are connected between the voltage input port and the voltage output port, each step-down unit comprises a capacitor and an inductor, and the connection relationship of the capacitor and / or inductor in each step-down unit is adjustable; A gating unit, used for adjusting the connection relationship between the capacitors and / or inductors in the two step-down units; Wherein, the step-down circuit includes a charging stage and a discharging stage; in the charging stage, the gating unit connects the capacitors and inductors in the two step-down units to the voltage input port and the voltage output port in a first connection mode, and in the first connection mode, the power supply voltage input by the voltage input port charges the capacitor and inductor of at least one step-down unit, and outputs to the voltage output port at the same time; in the discharging stage, the gating unit connects the capacitors and inductors in the two step-down units to the voltage input port and the voltage output port in a second connection mode, and in the second connection mode, the capacitor and inductor of at least one step-down unit discharges and outputs to the voltage output port; The two step-down units include a first step-down unit and a second step-down unit: The first step-down unit includes a first capacitor and a first inductor, the first capacitor is connected in series with the first inductor, and one end of the first capacitor not connected to the first inductor is selectively connected to the voltage input port or the voltage output port, and one end of the first inductor not connected to the first capacitor is selectively connected to the voltage output port; The second step-down unit includes a second capacitor and a second inductor, wherein the second capacitor and the second inductor are sequentially connected in series between an end of the first inductor that is not connected to the first capacitor and the voltage output port, and an end of the second capacitor that is connected to the first inductor is also selectively connected to the voltage output port; The gating unit is used to connect the first capacitor to the voltage input port or the voltage output port, and connect or disconnect the first inductor and the second capacitor to the voltage output port; Among them, in the charging stage, the gating unit connects the first capacitor to the voltage input port, and disconnects the first inductor and the second capacitor from the voltage output port, so that the first step-down unit and the second step-down unit are in a first connection mode as a whole, and the power supply voltage input by the voltage input port charges the first capacitor, the first inductor, the second capacitor and the second inductor, and outputs to the voltage output port at the same time; in the discharging stage, the gating unit disconnects the first capacitor from the voltage input port, and connects the first capacitor, the first inductor and the second capacitor to the voltage output port, so that the first step-down unit and the second step-down unit are in a second connection mode as a whole, and the first capacitor, the first inductor, the second capacitor and the second inductor discharge and output to the voltage output port.

2. The step-down circuit according to claim 1, characterized in that: The voltage input port includes a positive input terminal and a negative input terminal, the voltage output port includes a positive output terminal and a negative output terminal, the negative input terminal is connected to the negative output terminal, and the positive input terminal is used to input a power supply voltage; The second capacitor and the second inductor are connected in series between one end of the first inductor not connected to the first capacitor and the positive output end in sequence, and the one end of the first capacitor not connected to the first inductor can be selectively connected to the positive input end or the positive output end, the one end of the first inductor not connected to the first capacitor and the one end of the second capacitor connected to the first inductor can be selectively connected to the positive output end, and the one end of the first capacitor connected to the first inductor, the one end of the first inductor connected to the first capacitor, the one end of the second capacitor not connected to the first inductor and the one end of the second inductor connected to the second capacitor can be selectively connected to the negative output end; The selection unit is used to connect the first capacitor to the positive input terminal or the positive output terminal, and to connect or disconnect the first inductor and the second capacitor to the positive output terminal, and to connect or disconnect the first capacitor, the first inductor, the second capacitor and the second inductor to the negative output terminal.

3. The step-down circuit according to claim 2, characterized in that: The gating unit includes a first switch, a second switch, a first diode, a second diode and a third diode, the first switch is connected between the positive input terminal and the end of the first capacitor not connected to the first inductor, the second switch is connected between the end of the first capacitor not connected to the first inductor and the end of the second inductor not connected to the first capacitor, the positive electrode of the first diode is connected to the connection point between the second capacitor and the second inductor, the negative electrode of the first diode is connected to the connection point between the first capacitor and the first inductor, the positive electrode of the second diode is connected to the connection point between the first inductor and the second capacitor, the negative electrode of the second diode is connected to the connection point between the first capacitor and the second switch, the positive electrode of the third diode is connected to the connection point between the negative input terminal and the negative output terminal, and the negative electrode of the third diode is connected to the connection point between the second capacitor and the second inductor; The first switch and the second switch are complementarily turned on or off at a certain duty cycle, the first diode, the second diode and the third diode are unidirectional conducting diodes, and are turned on or off according to the current flow. The first switch, the second switch, the first diode, the second diode and the third diode cooperate to connect the first capacitor to the positive input terminal or the positive output terminal, and connect or disconnect the first inductor and the second capacitor to the positive output terminal, and connect or disconnect the first capacitor, the first inductor, the second capacitor and the second inductor to the negative output terminal, so as to switch the charging stage or the discharging stage of the buck circuit.

4. The step-down circuit according to claim 3, characterized in that: In the charging stage, the first switch is turned on, the second switch is turned off, the first diode, the second diode and the third diode are all turned off, and the first capacitor is connected to the positive input terminal through the turned-on first switch; In the discharge stage, the first switch is turned off, the second switch is turned on, the first diode, the second diode and the third diode are all turned on, the first capacitor, the first inductor, the second capacitor and the second inductor are connected to the positive output end through the turned-on second switch and the second diode, and the first capacitor, the first inductor, the second capacitor and the second inductor are connected to the negative output end through the turned-on first diode and the third diode.

5. The step-down circuit according to claim 3, characterized in that: The buck circuit also includes a control unit, which is used to output a corresponding control signal to control the first switch and the second switch to be turned on or off, and to control the on-duty cycle of the first switch and the second switch by adjusting the duty cycle of the corresponding control signal.

6. The step-down circuit according to claim 2, characterized in that: The step-down circuit further includes an output capacitor, one end of the output capacitor is connected to the positive output terminal, and the other end of the output capacitor is connected to the negative output terminal; In the charging stage, the power supply voltage input to the positive input terminal also charges the output capacitor; in the discharging stage, the positive output terminal is also outputted through the output capacitor.

7. The step-down circuit according to claim 1, characterized in that: The output voltage of the voltage output port, the voltage difference across the first capacitor, and the voltage difference across the second capacitor are all equal.

8. The step-down circuit according to any one of claims 1 to 7, characterized in that: The voltage input port is a DC voltage input port, and the voltage output port is a DC voltage output port.

9. A power supply device, characterized in that: The step-down circuit comprises the step-down circuit described in any one of claims 1 to 8.

Images