Inductor, voltage conversion circuit and electronic equipment

Abstract

An inductor, a voltage conversion circuit, and an electronic device relate to the field of electronic technology. The inductor comprises a magnetic core (X) and a first coil (L01) and a second coil (L02) wound on the magnetic core (X); the first coil (L01) and the second coil (L02) are connected in series between a first end and a second end of the inductor, wherein a pair of opposite-named ends of the first coil (L01) and the second coil (L02) are coupled.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to an inductor, a voltage conversion circuit, and an electronic device. Background Art

[0002] Switching power supplies are widely used to power chips in various electronic products, especially mobile devices like mobile phones and laptops. This creates a strong demand for miniaturized power supplies and improved efficiency across the board. 70% of mobile phone power consumption occurs in light-load conditions, such as standby mode. During these conditions, the chip on the phone requires a low supply current. Therefore, the power supply's conversion efficiency under light-load conditions determines the overall power consumption. When switching and running mobile applications (apps), the chip requires a high current in a short period of time. Therefore, the speed of app switching and execution depends on the dynamic response speed of the power supply, a requirement that is increasingly demanding in high-end devices. In buck / buck-boost circuits, a larger power inductor's inductance improves the power supply's conversion efficiency but also reduces its dynamic response. A smaller inductance reduces the power supply's conversion efficiency but improves its dynamic response. While both power supply conversion efficiency and dynamic response are essential, they have opposing requirements for power inductor selection. A common solution is to install multiple inductors and select inductors with different inductance values ​​through circuits under light and heavy load conditions. However, the size of the power inductors required for multi-channel buck / buck-boost circuits increases significantly, seriously affecting the miniaturization of power supplies and thus hindering the miniaturization design of electronic products. Summary of the Invention

[0003] The embodiments of the present application provide an inductor, a voltage conversion circuit, and an electronic device, which can reduce the volume of the inductor.

[0004] To achieve the above objectives, this application adopts the following technical solutions:

[0005] In a first aspect, an inductor is provided. The inductor includes a magnetic core and at least two coils wound around the magnetic core; the at least two coils are connected in series between a first end and a second end of the inductor, wherein a pair of opposite-named ends of two adjacent coils are coupled. For example, the inductor includes a magnetic core and a first coil and a second coil wound around the magnetic core; the first coil and the second coil are connected in series between a first end and a second end of the inductor, wherein a pair of opposite-named ends of the first coil and the second coil are coupled. In this way, since at least two coils are wound on the same magnetic core and a pair of opposite-name ends of adjacent coils are coupled, the common magnetic circuit of at least two coils is tightly coupled or fully coupled, that is, the magnetic flux generated by any coil on the magnetic core will be superimposed on the magnetic flux generated by other coils on the magnetic core, thereby enhancing the total inductance of the inductor; relative to the prior art, independent inductors formed by winding at least one coil on their respective magnetic cores, when the independent inductors are connected in series, the total inductance is the sum of the inductances of each inductor. Since the independent inductors each use an independent magnetic core, the magnetic flux on the magnetic core is not enhanced. However, the solution provided by the present application, since the magnetic flux on the magnetic core is enhanced by the tight coupling or full coupling of each coil on the magnetic core, the total inductance generated will be enhanced relative to the series connection of independent inductors; therefore, relative to achieving the equivalent total inductance of independent inductors in series in the prior art, the solution provided by the present application can be implemented with a smaller volume, for example, the coil can use fewer turns or length, which is conducive to the miniaturization of power supplies and the miniaturization design of electronic products.

[0006] In an exemplary embodiment, the magnetic core is a cylindrical core, or the magnetic core is in the form of a closed loop. For example, the magnetic core can be a cylindrical core, typically fabricated into an I-shape, with the coil wound around the magnetic column between the upper and lower covers of the I-shaped core; or the magnetic core can be a circular or square ring. In this way, most or all of the magnetic fields generated by at least two coils pass through the magnetic core, and the common magnetic circuits of at least two coils are tightly coupled or fully coupled, meaning that the magnetic flux generated by any coil on the magnetic core is superimposed on the magnetic flux generated by the other coils on the magnetic core, thereby increasing the total inductance of the inductor.

[0007] In an exemplary embodiment, at least two coils differ in one or more of the following parameters: inductance, impedance, number of turns, or cross-sectional area. For example, the first coil and the second coil differ in one or more of the following parameters: inductance, impedance, number of turns, or cross-sectional area. Thus, when applied to a voltage conversion circuit, coils with different parameters can be selected to meet different conversion efficiency requirements. For example, if the direct current resistance (DCR) of the coil has a greater impact on the conversion efficiency of the voltage conversion circuit, a thicker coil with a larger cross-sectional area can be used.

[0008] In an exemplary embodiment, at least two coils are wound sequentially around the magnetic core; alternatively, at least two coils are wound simultaneously around the magnetic core. For example, a first coil is wound around the magnetic core first, and then a second coil is wound around the magnetic core. The second coil may cover the first coil or be wound directly around the magnetic core. Alternatively, the first and second coils may be combined into a single coil and wound simultaneously around the magnetic core.

[0009] In an exemplary embodiment, the coil is made of a single-strand conductor, such as a single-strand copper conductor, or a Litz wire, wherein the use of Litz wire can better reduce the skin effect.

[0010] In an exemplary embodiment, the inductor is formed integrally with a powdered magnetic core and a coil, wherein the coil is a laminated structure of a strip conductor wrapped around the magnetic core, wherein the thickness direction of the laminated structure is parallel to the magnetic loop direction of the magnetic core.

[0011] In a second aspect, a voltage conversion circuit is provided, comprising a switching circuit and an inductor according to the first aspect. The switching circuit and at least one coil on the inductor form a voltage conversion loop; the voltage conversion loop is coupled between a power supply and a load. The voltage conversion loop is configured to convert electrical energy output by the power supply into a predetermined power output for the load. In this solution, different switching circuits can be connected to one or more coils on the inductor to form different voltage loops to supply power to different loads, thereby enabling power supply to different loads under different operating conditions, such as light and heavy loads. Since at least two coils are wound on the same magnetic core and a pair of opposite-name ends of adjacent coils are coupled, the common magnetic circuit of at least two coils is tightly coupled or fully coupled, that is, the magnetic flux generated by any coil on the magnetic core will be superimposed on the magnetic flux generated by other coils on the magnetic core, thereby enhancing the total inductance of the inductor; relative to the prior art, independent inductors formed by winding at least one coil on their respective magnetic cores, when the independent inductors are connected in series, the total inductance is the sum of the inductances of each inductor. Since the independent inductors each use an independent magnetic core, the magnetic flux on the magnetic core is not enhanced. However, the solution provided by the present application, since the tight coupling or full coupling of each coil on the magnetic core enhances the magnetic flux on the magnetic core, the total inductance generated will be enhanced relative to the series connection of independent inductors; therefore, relative to achieving the equivalent total inductance of independent inductors in series in the prior art, the solution provided by the present application can be implemented in a smaller volume, which is conducive to the miniaturization of power supplies and the miniaturization design of electronic products.

[0012] In one exemplary embodiment, to implement the voltage conversion circuit's step-down function, the switching circuit is coupled between a first terminal of an inductor and a power source, with a second terminal of the inductor coupled to a load. Alternatively, the switching circuit is coupled between the opposite-terminal terminals of any two adjacent coils and a power source, with the second terminal of the inductor coupled to the load.

[0013] In one exemplary embodiment, to achieve the voltage-boosting function of the voltage conversion circuit, the second end of the inductor is coupled to the load via a switching circuit, while the first end of the inductor is coupled to the power supply. Alternatively, the switching circuit is coupled between the opposite-polarity terminals of any two adjacent coils and the load, while the first end of the inductor is coupled to the power supply.

[0014] In an exemplary embodiment, the switching circuit includes a half-bridge circuit. Furthermore, when used as a boost switching circuit, the switching transistor in the upper arm of the half-bridge circuit can be replaced with a diode, and when used as a buck switching circuit, the switching transistor in the lower arm of the half-bridge circuit can be replaced with a diode. Using switching transistors in both the upper and lower arms can achieve higher efficiency.

[0015] In a third aspect, an electronic device includes the voltage conversion circuit and the control circuit provided in the second aspect, wherein the control circuit is used to control the switching circuit.

[0016] The technical problems solved and the technical effects achieved by the solution provided in the third aspect can be referred to the descriptions in the first and second aspects and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of the structure of a BUCK circuit provided in an embodiment of the present application;

[0019] Figure 3 A schematic structural diagram of a BUCK circuit provided in another embodiment of the present application;

[0020] Figure 3a A schematic structural diagram of a BUCK circuit provided in yet another embodiment of the present application;

[0021] Figure 3b A schematic structural diagram of a BUCK circuit provided in yet another embodiment of the present application;

[0022] Figure 3c A schematic structural diagram of a BUCK circuit provided in another embodiment of the present application;

[0023] Figure 4 A schematic diagram of the structure of a BOOST circuit provided in an embodiment of the present application;

[0024] Figure 5 A schematic structural diagram of a BOOST circuit provided in another embodiment of the present application;

[0025] Figure 6 A schematic structural diagram of a control circuit of a switch circuit provided in an embodiment of the present application;

[0026] Figure 7 A schematic diagram of the structure of a voltage conversion circuit provided in an embodiment of the present application;

[0027] Figure 8 A schematic structural diagram of a voltage conversion circuit provided in another embodiment of the present application;

[0028] Figure 9 A schematic structural diagram of an inductor provided in an embodiment of the present application;

[0029] Figure 10 A schematic structural diagram of an inductor provided in another embodiment of the present application;

[0030] Figure 11 A schematic structural diagram of an inductor provided in yet another embodiment of the present application;

[0031] Figure 12 A schematic structural diagram of an inductor provided in yet another embodiment of the present application;

[0032] Figure 13 A schematic structural diagram of an inductor provided in another embodiment of the present application;

[0033] Figure 14 A schematic structural diagram of an inductor provided in yet another embodiment of the present application;

[0034] Figure 15 A schematic structural diagram of an inductor provided in yet another embodiment of the present application;

[0035] Figure 16 A schematic structural diagram of an inductor provided in another embodiment of the present application;

[0036] Figure 17 A schematic structural diagram of a voltage conversion circuit provided in yet another embodiment of the present application;

[0037] Figure 18 A schematic structural diagram of a voltage conversion circuit provided in yet another embodiment of the present application;

[0038] Figure 19 A schematic structural diagram of an inductor provided in yet another embodiment of the present application;

[0039] Figure 20 A schematic structural diagram of a voltage conversion circuit provided in another embodiment of the present application;

[0040] Figure 21A schematic structural diagram of a voltage conversion circuit provided in yet another embodiment of the present application;

[0041] Figure 22 A schematic structural diagram of a voltage conversion circuit provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0043] In the following, the terms "first," "second," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the quantity of the technical features indicated. Therefore, a feature specified as "first," "second," etc. may explicitly or implicitly include one or more of the features.

[0044] In addition, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to changes in the orientation of the components in the drawings.

[0045] In this application, unless otherwise specified or limited, the term "connection" should be understood broadly. For example, "connection" can mean fixed connection, detachable connection, or integration; it can mean direct connection or indirect connection through an intermediate medium. In addition, the term "coupling" can refer to the method of electrical connection for signal transmission. "Coupling" can mean direct electrical connection or indirect electrical connection through an intermediate medium.

[0046] The embodiment of the present application provides an electronic device, which includes, for example, a mobile phone, a tablet computer, a car computer, a smart wearable product, etc. The embodiment of the present application does not impose any special restrictions on the specific form of the above electronic device. For the convenience of explanation, the following description is based on the example of the electronic device being a mobile phone. Figure 1 As shown, the electronic device 01 includes a display module 10 , a middle frame 11 and a rear cover 12 .

[0047] The display module 10 is used to display images. In some embodiments of the present application, the display module 10 includes a liquid crystal display (LCD) module and a backlight unit (BLU). Alternatively, in other embodiments of the present application, the display module 10 may be an organic light emitting diode (OLED) display.

[0048] The middle frame 11 is located between the display module 10 and the rear shell 12, and the side of the middle frame 11 facing the display module 10 is used to support the display module 10. In addition, the above-mentioned electronic device 01 also includes a printed circuit board (PCB). The side surface of the middle frame 11 facing the rear shell 12 is used to support electronic components such as the PCB, camera, and battery. Among them, the camera and battery are not shown in the figure. The rear shell 12 is connected to the middle frame 11 to form a accommodating cavity for accommodating the above-mentioned PCB, camera, battery and other electronic components. This can prevent external moisture and dust from invading the accommodating cavity and affecting the performance of the above-mentioned electronic components.

[0049] In addition, the electronic device 01 further includes a voltage conversion circuit (or a switching power supply) and a control circuit. The voltage conversion circuit and the control circuit are arranged on the PCB, and the control circuit is used to control the switching circuit. The voltage conversion circuit is coupled between the power supply (battery) and some loads (chips) on the PCB. For example, the voltage conversion circuit is coupled between the battery and the following chips, such as a system on chip (SoC), a central processing unit (CPU), or a graphics processing unit (GPU). The voltage conversion circuit is used to convert the voltage of the battery, for example, after stepping down or stepping up, it is provided as an operating voltage to the above-mentioned chips. The voltage conversion circuit can be a buck circuit, a boost circuit, or a buck-boost circuit.

[0050] The voltage conversion circuit includes a switch circuit and an inductor. Figure 2As shown, a BUCK circuit 02 is provided, comprising: an inductor 21, a switching circuit 22 (including: a switch tube Q, a diode D) and a capacitor Co. The switch tube Q can be a transistor. The first electrode of the switch tube Q, such as the source (source, s), is coupled to the input terminal Vin of the BUCK circuit 02, and the input terminal Vin of the BUCK circuit 02 can be coupled to a power supply, such as the positive electrode of a battery. The second electrode of the switch tube Q, such as the drain (drain, d), is coupled to the first end of the inductor 21. The second end of the inductor 21 is coupled to the output terminal Vout of the BUCK circuit 02. The gate (gate, g) of the switch tube Q is used to receive a control signal sent by the control circuit, and the control signal can control the conduction and cutoff of the switch tube Q. In addition, the cathode (cathode, c) of the diode D is coupled to the first end of the inductor 21, and the anode (anode, a) is coupled to the power supply, such as the negative electrode of the above-mentioned battery. The first end of the capacitor Co is coupled to the output terminal Vout of the BUCK circuit 02, and the second end is coupled to the power supply, such as the negative electrode of the above-mentioned battery. The inductor 21 has the functions of energy storage and filtering. When the switch tube Q is turned on, the power supply charges the inductor 21. When the switch tube Q is turned off, the inductor 21 discharges and continuously provides a stable operating voltage to each chip through the capacitor Co. In order to improve the efficiency of the power supply, the diode D in the BUCK circuit 02 can usually be replaced by a switch tube, so that the switching circuit is replaced by a half-bridge circuit. The above, Figure 2 In the scheme, the switch tube Q is described as a PMOS (positive channel metal oxide semiconductor, P-type metal oxide semiconductor field effect transistor) as an example. Of course, the switch tube Q can also be an NMOS (negative-MOS, N-type metal oxide semiconductor field effect transistor). The difference is that when the switch tube Q is an NMOS, the drain d of the switch tube Q is coupled to the input terminal Vin of the BUCK circuit 02, and the source s of the switch tube Q is coupled to the first end of the inductor 21. Figure 3 As shown, a BUCK circuit 03 is provided, and Figure 2 The difference is Figure 2The diode D in the BUCK circuit 02 provided in the embodiment is replaced with a switch tube. The BUCK circuit 03 includes a half-bridge circuit formed by a series connection of switch tubes Q1 and Q2. The upper arm of the half-bridge circuit is switch tube Q1 (the source of Q1 is coupled to Vin, and the drain of Q1 is coupled to the drain of switch tube Q2), and the lower arm is switch tube Q2 (the source of Q2 is coupled to a power supply, such as the negative terminal of the aforementioned battery). The inductor 21 is connected in series between the middle node of the half-bridge circuit (the connection point between the drain d of Q1 and the drain d of Q2) and the output terminal Vout of the BUCK circuit 03. The control circuit inputs a first control signal to the gate g of Q1, and a second control signal to the gate g of Q2. The first control signal can control the conduction and cutoff of switch tube Q1; the second control signal can control the conduction and cutoff of switch tube Q2. When switch tube Q1 is on, the power supply charges inductor 21. When the switch tube Q1 is turned off and Q2 is turned on, the inductor 21 discharges and continuously provides a stable operating voltage to each chip through the capacitor Co. Figure 3 In the solution provided, the switch tube Q1 is PMOS and the switch tube Q2 is NMOS. Of course, in other solutions, the switch tubes Q1 and Q2 can both be PMOS or NMOS; or the switch tube Q1 can be NMOS and the switch tube Q2 can be PMOS. Figure 3a As shown, a BUCK circuit 03a is provided, wherein Q1 adopts PMOS, Q2 adopts PMOS, and Figure 3 The difference is that in Figure 3a The source s of Q2 is coupled to the drain d of Q1, and the drain d of Q2 is coupled to a power source, such as the negative electrode of the battery. Figure 3b As shown, a BUCK circuit 03b is provided, wherein Q1 adopts NMOS, Q2 adopts NMOS, and Figure 3 The difference is that in Figure 3b The drain d of Q1 is coupled to the input terminal Vin of the BUCK circuit 03b, and the source s of Q1 is coupled to the first end of the inductor 21. Figure 3c As shown, a BUCK circuit 03c is provided, wherein Q1 adopts NMOS and Q2 adopts PMOS. Figure 3 The difference is that in Figure 3cIn the circuit, the drain d of Q1 is coupled to the input terminal Vin of the buck circuit 03b, and the source s of Q1 is coupled to the first end of the inductor 21. The source s of Q2 is coupled to the source s of Q1, and the drain d of Q2 is coupled to a power source, such as the negative terminal of the aforementioned battery. However, when a PMOS transistor is used as the upper arm, the s-pole is directly connected to Vin, and the s-pole voltage is fixed. It only needs the g-pole voltage to be lower than the s-pole voltage to turn it on, which is convenient. When an NMOS transistor is used as the lower arm, the s-pole is directly connected to the negative terminal of the battery (which is a fixed value), and it only needs to increase the g-pole voltage to turn it on, such as by fixing it to the voltage of Vin, to turn it on. This simplifies the circuit design. When other approaches are used, such as when an NMOS transistor is used as the upper arm, the d-pole is connected to Vin, and the s-pole voltage is not fixed, it is impossible to determine the g-pole voltage that controls the conduction of the NMOS transistor. This is because the s-pole voltage relative to ground has two states: a low level when the MOS transistor is off and close to the high level Vin when it is on. Therefore, when using an NMOS transistor as the high-side bridge, a separate isolated power supply control or bootstrap boost circuit must be designed. Similarly, when using a PMOS transistor as the low-side bridge, the d-terminal is connected to the negative terminal of the battery, the s-terminal voltage is not fixed (low level or Vin), and the g-terminal voltage cannot be determined. Therefore, a separate isolated power supply control or bootstrap boost circuit must be designed.

[0051] like Figure 4 As shown, a boost circuit 04 is provided, comprising an inductor 41, a switching circuit 42 (including a switch Q and a diode D), and a capacitor Co. The switch Q can be a transistor. The first end of the inductor 41 is coupled to the input terminal Vin of the boost circuit 04, which can be coupled to a power source, such as the positive electrode of a battery. The first terminal of the switch Q, such as the drain (d), is coupled to the second end of the inductor 41. The second terminal of the switch Q, such as the source (s), is coupled to a power source, such as the negative electrode of the battery. The gate (g) of the switch Q is used to receive a control signal sent by a control circuit, which can control the conduction and cutoff of the switch Q. In addition, the anode (anode) of the diode D is coupled to the second end of the inductor 41, and the cathode (c) is coupled to the output terminal Vout of the boost circuit 04. The inductor 41 has the functions of energy storage and filtering. When the switch Q is turned on, the inductor 41 is charged. When the switch tube Q is turned off, the inductor 41 forms a series structure with the power supply to discharge (because the inductor 41 and the power supply are in series, the voltage is increased, achieving the BOOST effect), and the capacitor Co continuously provides a stable operating voltage to each chip. To improve the efficiency of the power supply, the diode D in the BOOST circuit 04 can usually be replaced with a switch tube, so that the switching circuit is replaced with a half-bridge circuit. Figure 4The switch tube Q in the solution is described using NMOS as an example. Of course, the switch tube Q can also be PMOS. The difference is that when the switch tube Q is PMOS, the source of the switch tube Q is coupled to the second end of the inductor 41, and the drain d of the switch tube Q is coupled to the power supply, such as the negative electrode of the battery. Figure 5 As shown, a BOOST circuit 05 is provided, and Figure 5 The difference is Figure 4 The diode D in the BOOST circuit 04 provided in the embodiment is replaced with a switch tube. The BOOST circuit 05 includes a bridge circuit formed by a series connection of switch tubes Q3 and Q4. The upper arm of the half-bridge circuit is switch tube Q4 (source s of Q4 is coupled to Vout of the BOOST circuit 04, and drain d of Q4 is coupled to drain d of switch tube Q3). The lower arm is switch tube Q3 (source s of Q3 is coupled to a power supply, such as the negative terminal of the battery mentioned above). Inductor 41 is connected in series between the middle node of the bridge circuit (the connection point between drain d of Q4 and drain d of Q3) and the input terminal Vin of the BOOST circuit 05. The gate g of Q3 receives a third control signal, and the gate g of Q4 receives a fourth control signal. The third control signal can control the conduction and cutoff of switch tube Q3; the fourth control signal can control the conduction and cutoff of switch tube Q4. When switch tube Q3 is turned on, inductor 41 is charged. When the switch tube Q3 is turned off and Q4 is turned on, the inductor 41 and the power supply form a series structure to discharge, and continuously provide a stable operating voltage to each chip through the capacitor Co. Figure 5 In the solution provided, the switch tube Q3 is NMOS, and the switch tube Q4 is NMOS for example. Of course, in other solutions, the switch tubes Q3 and Q4 can both be PMOS, or both be NMOS; or the switch tube Q3 can be NMOS and the switch tube Q4 can be PMOS. Figure 3 The bridge in the provided BUCK circuit is similar and will not be described in detail.

[0052] In the following schemes, the switching circuit mentioned can use at least any of the switching circuits mentioned in the above examples. The above control signal can be a PWM signal generated by a pulse width modulation (PWM) generator. Taking the BUCK circuit as an example, the control signal is usually generated by a PWM generator, such as Figure 6As shown, a control circuit for a switching circuit is provided, wherein the output end of a PWM generator is connected to the gate g of a switching tube in the switching circuit; the input end of the PWM generator is connected to the output end of a comparator (CMP), a first input end of the CMP inputs a ramp voltage Vramp0, and Vramp0 is a ramp voltage of a desired operating frequency; a second input end of the CPM is connected to the output end of an error amplifier (EA), a positive input end of the error amplifier inputs a reference voltage Vref, and a negative input end of the EA is connected to the output end Vout of a voltage conversion circuit. Among them, Vref is the desired output voltage value of the output terminal Vout. When the output voltage of the output terminal Vout of the voltage conversion circuit is less than Vref, EA generates a positive deviation voltage output, causing the voltage value of the second input terminal of CMP to change (increase or decrease is related to the positive and negative pole wiring of CMP). CMP generates a control signal with the same frequency as Vramp0 based on the deviation voltage and Vramp0, and outputs it to the PWM generator, so that the output voltage increases until it reaches the desired voltage; when the output voltage of the output terminal Vout of the voltage conversion circuit is greater than Vref, CMP controls the PWM generator so that the generated PWM signal controls the conduction time of the upper arm of the bridge in the switching circuit to decrease (the duty cycle is reduced), and the output voltage drops to the desired voltage.

[0053] In order to balance the conversion efficiency and dynamic response of the voltage conversion circuit, multiple inductors are usually installed in the prior art. In the light and heavy load states, inductors with different inductance values ​​are selected through the circuit. Figure 7 As shown, the BUCK circuit 07 includes two switch circuits (switch circuits 0 and 1) and two inductors (L0 and L1) between the input terminal Vin and the output terminal Vout; the switch circuit 0 is coupled to the load through the inductor L0 (coupled to the load through the port Vout), and the switch circuit 1 is coupled to the load through the inductor L1. Under light load conditions, the switch circuit 0 works and uses the large inductor L0 to obtain higher conversion efficiency; under heavy load conditions, the switch circuit 1 works and uses the small inductor L1 to ensure good transient performance. At the same time, the directive current resistance (DCR) of the small inductor is small, and the conversion efficiency is higher. In another example, referring to Figure 8As shown, the BUCK circuit 08 includes two switching circuits (switch circuits 0 and 1) and two inductors (L0 and L1) between the input terminal Vin and the output terminal Vout; inductors L0 and L1 are connected in series; switch circuit 0 is coupled to the load through inductors L0 and L1 (coupled to the load through port Vout), and switch circuit 1 is coupled to the load through inductor L1; under light load conditions, switch circuit 0 operates, and the equivalent inductance used at this time is the inductance of L0 + L1 (large inductance) to ensure conversion efficiency; while under heavy load conditions, switch circuit 1 operates, and the equivalent inductance used at this time is the inductance of L1 (small inductance), which can achieve better transient performance and conversion efficiency under heavy load conditions. In both of the above examples, two independent inductors L0 and L1 are required, which doubles the board area, affects the miniaturization of the power supply, and is not conducive to the miniaturization design of electronic products.

[0054] To address the aforementioned issues, an embodiment of the present application provides an inductor comprising a magnetic core and at least two coils wound around the magnetic core; the at least two coils are connected in series between a first end and a second end of the inductor, with a pair of opposite-named ends of adjacent coils coupled. For example, the inductor comprises a magnetic core and a first coil and a second coil wound around the magnetic core; the first coil and the second coil are connected in series between the first end and the second end of the inductor, with a pair of opposite-named ends of the first coil and the second coil coupled. In this way, since at least two coils are wound on the same magnetic core and a pair of opposite-name ends of adjacent coils are coupled, the common magnetic circuit of at least two coils is tightly coupled or fully coupled, that is, the magnetic flux generated by any coil on the magnetic core will be superimposed on the magnetic flux generated by other coils on the magnetic core, thereby enhancing the total inductance of the inductor; relative to the prior art, independent inductors formed by winding at least one coil on their respective magnetic cores, when the independent inductors are connected in series, the total inductance is the sum of the inductances of each inductor. Since the independent inductors each use an independent magnetic core, the magnetic flux on the magnetic core is not enhanced. However, the solution provided by the present application, since the magnetic flux on the magnetic core is enhanced by the tight coupling or full coupling of each coil on the magnetic core, the total inductance generated will be enhanced relative to the series connection of independent inductors; therefore, relative to achieving the equivalent total inductance of independent inductors in series in the prior art, the solution provided by the present application can be implemented with a smaller volume, for example, the coil can use fewer turns or length, which is conducive to the miniaturization of power supplies and the miniaturization design of electronic products.

[0055] For example, Figure 9Taking the illustrated solution as an example, inductor 09 comprises two coils L01 and L02 and a magnetic core X. Coils L01 and L02 are wound around magnetic core X, with L01's first end ① serving as the inductor's first end, L01's second end ② coupled to L02's first end ①, and L02's second end ② serving as the inductor's second end. L01's first end ① and L02's second end ② form a pair of opposite-name terminals, while L01's second end ② and L02's first end ① form a pair of opposite-name terminals. Because L01 and L02 are wound around the same magnetic core, they form a common magnetic circuit and are coupled to each other. Their series equivalent inductance is:

[0056]

[0057] Among them, l eq1 is the equivalent inductance of inductor 09, l01 is the equivalent inductance of coil L01, l02 is the equivalent inductance of coil L02, and k is the coupling coefficient, where k = 1 is full coupling, k is close to 1 is tight coupling, and k is small is loose coupling.

[0058] And refer to Figure 10 As shown, taking the prior art of two independent tapped inductors connected in series as an example, since there is no coupling between the tapped inductors, the coil L01 of the inductor 101 and the coil L02 of the inductor 102 are connected in series. Figure 10 The inductance of the two inductors is respectively Figure 9 When the inductance of the two coils is the same (i.e. Figure 10 The inductance generated by the coil L01 of the inductor 101 is also l01, and the inductance generated by the coil L02 of the inductor 102 is also l02). Since the magnetic core X1 and the magnetic core X2 are not coupled, Figure 10 The equivalent inductance of the two inductors connected in series is:

[0059] l eq2 =l01+l02; obviously l eq2 ≤l eq1 .

[0060] It can be seen that with the same size and winding, the equivalent inductance can be doubled when the tight coupling method is used. According to the relationship between inductance, coil length and number of turns, it can be seen that the inductor coil provided by this application can use fewer turns or length to achieve the same equivalent inductance, so the same equivalent inductance can be achieved with a smaller volume. In addition, Figure 9 In the inductor 09 shown, when the second end ② of L01 and the first end ① of L02 are directly coupled inside the inductor, a shorter trace can be achieved compared to the external connection of the tapped inductor, so the DCR is smaller. Figure 9The winding method of L01 and L02 is explained by taking L01 and L02 as an example of winding in the same direction. In this way, one pair of opposite-name terminals of L01 and L02 is located between the other pair of opposite-name terminals. The second terminal ② of L01 and the first terminal ① of L02 can be directly coupled inside the inductor. If L01 and L02 are wound in opposite directions, then Figure 11 As shown, the distance between the opposite ends of L01 and L02 is relatively far, and they can be connected in series through external coupling, such as Figure 11 As shown, an inductor 011 is provided, wherein the second end ② of the coil L01 and the first end ① of the coil L02 can be coupled via an external lead. In another implementation, the opposite-name ends of the parallel negative coupling inductors can also be coupled externally. Figure 12 As shown, the inductor 012 includes coils L01 and L02 wound on the magnetic core X, wherein the winding directions of L01 and L02 are opposite (i.e., as shown in FIG. Figure 12 As shown, the opposite ends of L01 and L02 are located on the same side, that is, the second end ② of L01 and the first end ① of L02 are located on the same side, and the first end ① of L01 and the second end ② of L02 are located on the same side). In this embodiment, the second end ② of L01 and the first end ① of L02 can be coupled through an external lead.

[0061] This application does not limit the shape of the magnetic core used in the inductor. For example, it can be a cylindrical magnetic core, which is usually made into an I-shape during the manufacturing process, with the coil wound on the magnetic column between the upper and lower covers of the I-shaped magnetic core; or the magnetic core can be shaped as a closed loop, such as a circular ring or a square ring. In this way, most or all of the magnetic field generated by at least two coils passes through the magnetic core, and the common magnetic circuit of at least two coils is tightly coupled or fully coupled. That is, the magnetic flux generated by any coil on the magnetic core will be superimposed on the magnetic flux generated by the other coils on the magnetic core, thereby increasing the total inductance of the inductor. The parameters of the coils can vary depending on the actual load power requirements. For example, the inductance, impedance, number of turns, cross-sectional area, and other parameters of each coil can be different. Therefore, when applied to voltage conversion circuits, coils with different parameters can be selected to meet different conversion efficiency requirements. For example, if the DCR of the coil has a greater impact on the conversion efficiency of the voltage conversion circuit, a thicker coil with a larger cross-sectional area can be used.

[0062] The coil can be made of a single-strand wire, such as a single-strand copper wire; or to reduce the skin effect, the coil can also be made of Litz wire. The coil can be wound in sequence or simultaneously. Figure 13 As shown, a schematic diagram of the structure of an inductor 013 is provided, wherein coils L01 and L02 are wound on a magnetic core X in sequence, and the second end ② of L01 is coupled to the first end ① of L02. Figure 13In the example shown, coil L01 is wound on the upper section of the magnetic core X, and coil L02 is wound on the lower section of the magnetic core. Of course, coil L01 can also be wound on the outside of L02, or L02 can be wound on the outside of L01, or L01 and L02 can be wound directly on the magnetic core. Or coils L01 and L02 can be wound on the magnetic core X at the same time, for example, L01 and L02 can be combined into one and wound on the magnetic core at the same time. It should be noted that combining L01 and L02 into one is only physically combining L01 and L02 together, not electrically connecting them. For example, L01 and L02 are combined together using enameled wire. Although they are close together, the electrical connection relationship still refers to the above-mentioned form of coupling a pair of opposite ends. In addition, the inductor can be formed integrally with a powdered magnetic core and a coil. For example: the coil is a laminated structure of a strip conductor wrapped around the magnetic core, wherein the thickness direction of the laminated structure is parallel to the magnetic circuit direction of the magnetic core. As Figure 14 As shown, the inductor 014 can be realized by using copper foil stacking. The copper foil thickness of coils L01 and L02 can be different, and the stacking spacing can also be different. The thickness direction of the copper foil stacking structure is as follows: Figure 14 As shown, the direction of the magnetic circuit is the same as that of the magnetic core (according to the right-hand rule, when the current in the coil of the inductor flows in different directions, there may be magnetic circuit direction one (corresponding to current direction one) or magnetic circuit direction two (corresponding to current direction two)). Figure 15 、 Figure 16 The packaged inductor device can provide a three-terminal or four-terminal interface, such as Figure 15 、 Figure 16 As shown, after the second end ② of L01 is coupled with the first end ① of L02, an interface (PAD1, PAD4, or only one of the two) is provided externally. The first end ① of L01 provides an interface PAD3 externally, and the second end ② of L02 provides an interface PAD2 externally.

[0063] Of course, the above description is mainly based on the example of two coils connected in series. Of course, in other examples, the inductor provided by the embodiment of the present application may also include more coils connected in series.

[0064] When the inductor provided by embodiments of this application is used in a voltage conversion circuit, the voltage conversion circuit includes a switching circuit and an inductor. The switching circuit and at least one coil of the inductor form a voltage conversion loop, which is coupled between a power supply and a load. The voltage conversion loop is used to convert the electrical energy output by the power supply into a predetermined power output for the load.

[0065] In this solution, different switching circuits can be connected to one or more coils on the inductor to form different voltage loops to supply power to different loads, thereby achieving power supply to different loads under different working conditions such as light load and heavy load states. Since at least two coils are wound on the same magnetic core and a pair of opposite-name ends of adjacent coils are coupled, the common magnetic circuit of at least two coils is tightly coupled or fully coupled, that is, the magnetic flux generated by any coil on the magnetic core will be superimposed on the magnetic flux generated by other coils on the magnetic core, thereby enhancing the total inductance of the inductor; relative to the prior art, independent inductors formed by winding at least one coil on their respective magnetic cores, when the independent inductors are connected in series, the total inductance is the sum of the inductances of each inductor. Since the independent inductors each use an independent magnetic core, the magnetic flux on the magnetic core is not enhanced. However, the solution provided by the present application, since the tight coupling or full coupling of each coil on the magnetic core enhances the magnetic flux on the magnetic core, the total inductance generated will be enhanced relative to the series connection of independent inductors; therefore, relative to achieving the equivalent total inductance of independent inductors in series in the prior art, the solution provided by the present application can be implemented in a smaller volume, which is conducive to the miniaturization of power supplies and the miniaturization design of electronic products.

[0066] The switch circuit and the inductor can form a voltage conversion circuit with a buck function, a boost function, or a buck-boost function.

[0067] Combined with the above Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 Regarding the description of the BUCK and BOOST circuits, when used for bucking, the switching circuit is coupled between the first end of the inductor and the power supply, and the second end of the inductor is coupled to the load. Alternatively, the switching circuit is coupled between the opposite-signal terminals of any two adjacent coils and the power supply, and the second end of the inductor is coupled to the load. When used for boosting, the second end of the inductor is coupled to the load via either switching circuit, and the first end of the inductor is coupled to the power supply. Alternatively, the switching circuit is coupled between the opposite-signal terminals of any two adjacent coils and the load, and the first end of the inductor is coupled to the power supply.

[0068] The following describes the application of inductors in voltage conversion circuits with specific examples:

[0069] Take the inductance formed by two coils in series as an example (i.e. using Figure 9 In Example 1, a BUCK circuit is provided, referring to Figure 17As shown, the buck circuit 017 includes switch circuit 0 and switch circuit 1. Switch circuit 0 is coupled between the first end of the inductor (i.e., the first end ① of coil L01) and the power supply (i.e., Vin), and switch circuit 1 is coupled between the opposite-terminal ends of coils L01 and L02 (i.e., the connection between the second end ② of L01 and the first end ① of L02) and the power supply. The second end ② of L02 is connected to the load via port Vout. When the buck circuit 017 is operating in a light-load state, switch circuit 0 is active, and the equivalent inductance connected to the buck circuit 017 is:

[0070]

[0071] where l eq1 is the equivalent inductance of the inductor, l01 is the equivalent inductance of the coil L01, l02 is the equivalent inductance of the coil L02, and the larger the inductance l eq1 The conversion efficiency is ensured under light load conditions. When the BUCK circuit 017 operates under heavy load conditions, the switch circuit 1 operates, the coil L01 does not operate, and the coil L02 operates. The equivalent inductance connected to the BUCK circuit 017 is l02. At this time, the smaller inductance ensures the response speed under heavy load conditions.

[0072] In Example 2, a BOOST circuit is provided, referring to Figure 18 As shown, the BOOST circuit 018 includes switch circuit 0 and switch circuit 1, wherein switch circuit 0 is coupled between the first end of the inductor (i.e., the first end ① of coil L01) and the load (i.e., connected to the load through Vout), and switch circuit 1 is coupled between the opposite-terminal ends of coils L01 and L02 (i.e., the connection between the second end ② of L01 and the first end ① of L02) and the load. The second end ② of L02 is connected to the power supply through port Vin. When the BOOST circuit 018 is operating in a light-load state, switch circuit 0 is in operation, and the equivalent inductance connected to the BOOST circuit 018 is:

[0073] where l eq1 is the equivalent inductance of the inductor, l01 is the equivalent inductance of the coil L01, and l02 is the equivalent inductance of the coil L02. eq1 The conversion efficiency is ensured under light load conditions. When the BOOST circuit 018 operates under heavy load conditions, the switch circuit 1 operates, the coil L01 does not operate, and the coil L02 operates. The equivalent inductance connected to the BOOST circuit 018 is l02. At this time, the smaller inductance ensures the response speed under heavy load conditions.

[0074] In Examples 1 and 2, the current carrying requirements of coils L01 and L02 can be the same or different. When the current carrying requirements of L01 and L02 are different, wires with different cross-sectional areas can be used. For example, coil L01, which does not carry current under heavy load, is wound with a smaller cross-sectional area (thin wire), while coil L02, which carries large current under heavy load, is wound with a larger cross-sectional area (thick wire). The DCR of the thick wire inductor is small, ensuring high efficiency under heavy load. In this way, because the DCR of coil L02 has a significant impact on the conversion efficiency of the voltage conversion circuit, L02 and L01 are wound with thick and thin wires, respectively. This solution can further reduce the compression cost and inductor volume.

[0075] The following is an example of the inductance formed by three coils connected in series. Figure 19 As shown, an inductor 019 is provided, comprising a coil L01, a coil L02, a coil L03 and a magnetic core X, wherein the coils L01, L02 and L03 are wound on the magnetic core X, and a pair of opposite-name ends of adjacent coils L01 and L02 are coupled (e.g. Figure 19 As shown, the second end ② of coil L01 is connected to the first end ① of coil L02, and a pair of opposite-name ends of adjacent coils L02 and L03 are coupled (as shown in FIG. Figure 19 As shown, the second end ② of the coil L02 and the first end ① of the coil L03). Based on the above-mentioned inductor 019, in Example 3, the embodiment of the present application provides a BUCK circuit 020, referring to Figure 20As shown, the BUCK circuit 020 includes switch circuit 0, switch circuit 1, and switch circuit 2, wherein switch circuit 0 is coupled between the first end of the inductor (i.e., the first end ① of coil L01) and the power supply (i.e., Vin), switch circuit 1 is coupled between the opposite-name ends of coils L01 and L02 (i.e., the connection between the second end ② of L01 and the first end ① of L02) and the power supply, and switch circuit 2 is coupled between the opposite-name ends of coils L02 and L03 (i.e., the connection between the second end ② of L02 and the first end ① of L03) and the power supply. The second end ② of L03 is connected to the load via port Vout. Based on Example 1, Example 3 provides a voltage conversion circuit that adapts to three different load conditions: light, medium, and heavy load conditions. When the buck circuit 020 operates in a light-load state, switch circuit 0 operates, L01, L02, and L03 are all connected to the load, and the total connected inductance is maximized, meeting the high conversion efficiency requirements under light-load conditions. When the buck circuit 020 operates in a medium-load state, switch circuit 1 operates, L02 and L03 are connected to the load, and the total connected inductance is moderate, meeting the performance requirements under medium-load conditions. When the buck circuit 020 operates in a heavy-load state, switch circuit 2 operates, and only L03 is connected to the load, minimizing the total connected inductance and the DCR, meeting the requirements of high efficiency and high transient performance. Similarly, to minimize the DCR under heavy-load conditions, L01, L02, and L03 can use coils with successively smaller inductances. For example, the cross-sectional areas of L01, L02, and L03 can be successively larger. Similar to Example 2, the inductor 019 formed by the three coils connected in series can also be used in boost circuits, and will not be further described here.

[0076] In Example 4, a BUCK-BOOST circuit is provided, referring to Figure 21 As shown, the buck-boost circuit includes switch circuit 0, switch circuit 1, switch circuit 2, and switch circuit 3. Switch circuit 0 is coupled between the first end of the inductor (i.e., the first end ① of coil L01) and the power supply (i.e., Vin). Switch circuit 1 is coupled between the opposite-terminal ends of coils L01 and L02 (i.e., the connection between the second end ② of L01 and the first end ① of L02) and the power supply. Switch circuit 2 is coupled between the opposite-terminal ends of coils L02 and L03 (i.e., the connection between the second end ② of L02 and the first end ① of L03) and the load (i.e., connected to the load via Vout). Switch circuit 3 is coupled between the second end ② of L03 and the load.

[0077] Among them, switch circuit 0 and switch circuit 3 are in non-operating state (refer to Figure 22As shown, switch circuits 0 and 3 are in the off state, that is, the switch tubes Q1, Q2, Q7 and Q8 in switch circuits 0 and 3 are in the off state), and switch circuits 1 and switch circuits 2 work together in the heavy load state of BUCK or BOOST mode: In BUCK mode, the input PWM signal of switch circuit 1 is in the PWM state (that is, Q3 and Q4 of switch circuit 1 are in the on and off switching state under the control of the PWM signal. Of course, Q4 can also be replaced by a diode with freewheeling function, such as Figure 2 The diode D in the switch circuit 2 is in the through state under the control of the control signal (i.e. Q6 is on and Q5 is off); in the BOOST mode, the switch circuit 1 is in the through state under the control of the control signal (Q3 is on and Q4 is off), and the switch circuit 2 is in the PWM state when the PWM signal is input (i.e. Q5 and Q6 of the switch circuit 2 are in the on and off switching state under the control of the PWM signal. Of course, Q6 can also be replaced by a diode with a freewheeling function, such as Figure 4 At this point, only coil L02 is connected to the load, and its inductance is relatively small, ensuring high transient performance. Of course, to minimize the DCR under heavy load conditions and improve circuit efficiency, coil L02 can have a smaller inductance than L01 and L02. For example, a coil with a larger cross-sectional area can be used for L02.

[0078] Switch circuits 0 and 2 are not in operation (refer to Figure 22 As shown, switch circuits 0 and 2 are in the off state, that is, the switch tubes Q1, Q2, Q5 and Q6 in switch circuits 0 and 2 are in the off state), and switch circuit 1 and switch circuit 3 work together in the light load state of BUCK or BOOST mode: In BUCK mode, the input PWM signal of switch circuit 1 is in the PWM state (that is, Q3 and Q4 of switch circuit 1 are in the on and off switching state under the control of the PWM signal. Of course, Q4 can also be replaced by a diode with freewheeling function, such as Figure 2 The diode D in the figure is removed. Switch circuit 3 is in the through state (i.e., Q8 is on and Q7 is off) under the control of the control signal. L02 and L03 are connected in series to the load. At this time, the equivalent inductance is:

[0079] l02 is the equivalent inductance of coil L02, l03 is the equivalent inductance of coil L03, and k is the coupling coefficient between L02 and L03.

[0080] In BOOST mode, the switch circuit 1 is in the through state under the control of the control signal (i.e. Q3 is on and Q4 is off), and the switch circuit 3 is in the PWM state when the PWM signal is input (i.e. Q7 and Q8 of the switch circuit 3 are in the on and off switching state under the control of the PWM signal. Of course, Q8 can also be replaced by a diode with freewheeling function, such as Figure 4 Diode D in the figure), L02 and L03 are connected in series to the load. The equivalent inductance is:

[0081] l02 is the equivalent inductance of coil L02, l03 is the equivalent inductance of coil L03, and k is the coupling coefficient between L02 and L03.

[0082] Switch circuits 1 and 3 are in the non-operating state (refer to Figure 22 As shown, switch circuits 1 and 3 are in the off state, that is, the switch tubes Q3, Q4, Q7 and Q8 in switch circuits 1 and 3 are in the off state), and switch circuit 0 and switch circuit 2 work together in the light load state of BUCK mode (where switch circuit 0 and switch circuit 2 cannot work together in BOOST mode because, during the Boost mode boost, L01 may continue to flow to the power supply Vin through Q3 of switch circuit 1): Switch circuit 2 is in the through state (that is, Q6 is on and Q5 is off) under the control of the control signal, and the equivalent inductance of the connected load is:

[0083] where l eq1 is the equivalent inductance of the inductor, l01 is the equivalent inductance of the coil L01, l02 is the equivalent inductance of the coil L02, and k is the coupling coefficient between L01 and L02.

[0084] Switch circuits 1 and 2 are not in operation (refer to Figure 22 As shown, switch circuits 1 and 2 are in the off state, that is, the switch tubes Q3, Q4, Q5 and Q6 in switch circuits 1 and 2 are in the off state), and switch circuit 0 and switch circuit 3 work together in the BUCK light load state (wherein switch circuit 0 and switch circuit 3 cannot work together in the BOOST mode because when the Boost mode is boosted, L01 may continue to flow to the power supply Vin through Q3 of switch circuit 1): switch circuit 3 is in the through state under the control of the control signal (that is, Q8 is on and Q7 is off), L01, L02, and L03 are connected in series to the load, and the equivalent inductance of the three in series is used. It can be seen that in the above example 4, the voltage conversion circuit provided can realize the connection of different equivalent inductances to the load by reusing coil L02 under different load conditions. Since coil L02 shares the magnetic core X with other coils, the equivalent inductance can be enhanced, which is conducive to reducing the overall volume of the inductor.

[0085] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A voltage conversion circuit, characterized in that: comprising a first switching circuit, a second switching circuit and an inductor; The inductor comprises a magnetic core and a first coil and a second coil wound on the magnetic core; The first coil and the second coil are connected in series between a first end and a second end of the inductor, wherein a pair of opposite-named ends of the first coil and the second coil are coupled; The first switch circuit is coupled to the first end or the second end of the inductor to form a voltage conversion loop; the voltage conversion loop is coupled between the power supply and the load; The second switching circuit is coupled between a pair of opposite-named terminals of the first coil and the second coil and a power supply, and the second end of the inductor is coupled to the load; or the second switching circuit is coupled between a pair of opposite-named terminals of the first coil and the second coil and the load, and the first end of the inductor is coupled to the power supply.

2. The voltage conversion circuit according to claim 1, wherein: The first switch circuit is coupled between a first terminal of the inductor and a power source, and a second terminal of the inductor is coupled to the load.

3. The voltage conversion circuit according to claim 1, wherein: The second end of the inductor is coupled to the load through the first switch circuit, and the first end of the inductor is coupled to the power supply.

4. The voltage conversion circuit according to claim 1, wherein: The magnetic core is a cylindrical magnetic core.

5. The voltage conversion circuit according to claim 1, wherein: The magnetic core is in a closed loop shape.

6. The voltage conversion circuit according to any one of claims 1 to 5, characterized in that: One or more of the following parameters of the first coil and the second coil are different: inductance, impedance, number of turns or cross-sectional area.

7. The voltage conversion circuit according to claim 1, wherein: The first coil and the second coil are wound on the magnetic core in sequence.

8. The voltage conversion circuit according to claim 1, wherein: The first coil and the second coil are wound on the magnetic core simultaneously.

9. The voltage conversion circuit according to any one of claims 1 to 5, characterized in that: The first coil and the second coil are made of single-strand wire or Litz wire.

10. The voltage conversion circuit according to any one of claims 1 to 5, characterized in that: The inductor is formed integrally with a powdered magnetic core and a coil.

11. The voltage conversion circuit according to claim 10, wherein: The first coil and the second coil are a stacked structure in which a strip conductor surrounds the magnetic core, wherein a thickness direction of the stacked structure is parallel to a magnetic loop direction of the magnetic core.

12. An electronic device, characterized in that: It comprises the voltage conversion circuit and the control circuit according to any one of claims 1 to 11, wherein the control circuit is used to control the switch circuit.

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