Multi-inductor multi-output DC voltage converter and control method thereof

Abstract

The invention discloses a multi-inductor multi-output DC voltage converter and a control method thereof, the converter comprises a plurality of basic unit modules and a charge redistribution module, the plurality of basic unit modules are connected in series, and the plurality of basic unit modules are all connected with the charge redistribution module. The method comprises the steps that according to an input voltage signal, based on a basic unit module, a first inductor is sequentially and alternately magnetized and demagnetized in a complete period, and load end output current and load end output voltage are obtained; and obtaining the first flight capacitance current, combining the load end output current and the load end output voltage, performing adjustment processing on the inductance current based on a charge redistribution module, and outputting the adjusted inductance current. According to the embodiment of the invention, the capability of supporting higher input voltage and more output channels can be enhanced, and external elements are reduced, so that the conversion efficiency of the system is improved. The method can be widely applied to the integrated circuit design technology.

Description

Technical Field

[0001] This application relates to the field of integrated circuit design technology, and particularly to a multi-inductor multi-output DC voltage converter and its control method. Background Art

[0002] Traditional inductor-based buck converter architectures face challenges such as increased control-stage design complexity, large size, and reduced efficiency in applications with a large voltage conversion ratio. A large voltage conversion ratio usually means a more extreme duty cycle (D, defined as V OUT / V IN ), which increases the difficulty of control. At the same time, the power switch needs to withstand a high voltage stress, so high-voltage transistors must be used. However, high-voltage transistors have large parasitic effects and poor FoM (Figures of Merit) values, deteriorating the efficiency. In addition, the voltage swing of the conversion node V SW is large, generating a large current ripple, which forces the use of an inductor with a larger inductance value, thereby increasing the DC resistance (DCR) of the inductor and further increasing the size of passive devices.

[0003] In summary, the technical problems existing in the related art need to be improved. Summary of the Invention

[0004] The main purpose of the embodiments of this application is to propose a multi-inductor multi-output DC voltage converter and its control method, which can enhance the ability to support higher input voltages and more output channels and reduce external components, thereby improving the system conversion efficiency.

[0005] To achieve the above object, on the one hand, an embodiment of this application proposes a multi-inductor multi-output DC voltage converter, where the converter includes a plurality of basic unit modules and a charge redistribution module. The plurality of basic unit modules are connected in series, and the plurality of basic unit modules are all connected to the charge redistribution module, where:

[0006] The basic unit module is used to reduce the switch withstand voltage and provide an output voltage;

[0007] The charge redistribution module is used to redistribute the capacitor charges in the basic unit module to achieve power decoupling.

[0008] In some embodiments, the basic unit module includes a first power switch, a second power switch, a third power switch, a first flying capacitor, a first DC capacitor, and a first inductor. The second terminal of the first DC capacitor is connected to the first terminal of the first power switch and is connected to a high-level voltage UP. The second terminal of the first power switch, the first terminal of the second power switch, and the first terminal of the first flying capacitor are connected to a second conversion node. The second terminal of the first flying capacitor, the first terminal of the third power switch, and the first terminal of the first inductor are connected to a first conversion node. The first terminal of the first DC capacitor is grounded. The second terminal of the third power switch is grounded. The second terminal of the second power switch is connected to a low-level voltage DOWN. The second terminal of the first inductor serves as the output terminal of the basic unit module.

[0009] In some embodiments, the first power switch, the second power switch, and the third power switch are used to switch the connection mode of the capacitor and the inductor. The first flying capacitor is used for energy transfer. The first DC capacitor is used to provide a voltage source with an intermediate level, decouple the duty cycles of the two cascaded basic unit modules before and after, and the first inductor is used to filter the switching node to obtain the output voltage.

[0010] In some embodiments, the charge redistribution module includes a plurality of power switch tubes and a second DC capacitor. The second terminal of the second DC capacitor is grounded. The first terminals of the second DC capacitor are all connected to the second terminals of the plurality of power switch tubes and the low-level voltage of the first basic unit module. The first terminals of the plurality of power switch tubes are respectively connected to the first conversion nodes of the plurality of basic unit modules.

[0011] To achieve the above object, on the other hand, an embodiment of the present application proposes a control method for a multi-inductor multi-output DC voltage converter, and the method includes the following steps:

[0012] According to the input voltage signal, based on the basic unit module, the first inductor is alternately magnetized and demagnetized in a complete cycle to obtain the load-side output current and the load-side output voltage;

[0013] Obtain the first flying capacitor current and combine the load-side output current and the load-side output voltage, and based on the charge redistribution module, adjust the inductor current to output the adjusted inductor current.

[0014] In some embodiments, during the magnetization stage of the first inductor, the first power switch in the basic unit module and the switching transistor in the charge redistribution module are both in the conducting state, the second power switch and the third power switch in the basic unit module are in the off state, the first flying capacitor in the basic unit module is connected to the second DC capacitor in the charge redistribution module through the switching transistor, and the first DC capacitor in the basic unit module charges the first flying capacitor and the first inductor through the first power switch.

[0015] In some embodiments, during the demagnetization stage of the first inductor, the first power switch in the basic unit module and the switching transistor in the charge redistribution module are both in the off state, the second power switch and the third power switch in the basic unit module are in the conducting state, the first flying capacitor in the basic unit module is disconnected from the first DC capacitor in the basic unit module and the second DC capacitor in the charge redistribution module, the first flying capacitor is in the discharging state, and the first inductor extracts charge from the ground terminal GND through the third power switch.

[0016] In some embodiments, it further includes:

[0017] During the magnetization period, the voltage of the first conversion node is the high-level voltage UP minus the low-level voltage DOWN, and the voltage of the second conversion node is the high-level voltage UP;

[0018] During the demagnetization stage, the voltage of the first conversion node is 0, and the voltage of the second conversion node is the low-level voltage DOWN.

[0019] In some embodiments, based on the charge redistribution module, the inductor current is adjusted so that the currents output by different output channels are independent of each other.

[0020] In some embodiments, it further includes:

[0021] The converter is periodically controlled. When the converter enters the steady-state operating state, the steady-state voltage on the first DC capacitor in the first basic unit module in the converter is V DC1 = 2×V IN / (N + 1), the steady-state voltage on the first DC capacitor in the second basic unit module is V DC2 = 3×V IN / (N + 1), the steady-state voltage on the first DC capacitor in the (N - 1)th basic unit module is V DC(N-1) = N×V IN / (N + 1), and the steady-state voltage of the first DC capacitor in the Nth basic unit module is V D □□ = (N + 1)×VIN / (N + 1);

[0022] The voltage stress of the first flying capacitor in the first basic unit module is V CF1 = 1 × V IN / (N + 1), the voltage stress of the first flying capacitor in the second basic unit module is V CF2 = 2 × V IN / (N + 1), the voltage stress of the first flying capacitor in the (N - 1)th basic unit module is V CF(N-1) = (N - 1) × V IN / (N + 1), the voltage stress of the first flying capacitor in the Nth basic unit module is V CFN = N × V IN / (N + 1), the steady-state voltage of the second DC capacitor in the charge redistribution module is V R = V IN / (N + 1);

[0023] Wherein, N represents the number of basic units of the converter, that is, the number of output channels, and V IN represents the input voltage.

[0024] The embodiments of the present application at least include the following beneficial effects: The present application provides a scalable multi-inductor multi-output DC voltage converter and its control method. This solution can reduce the switch voltage withstand and provide the output voltage through the basic unit module, so as to reduce the voltage stress on the switch and the inductor, and enhance the ability to support higher input voltages and more output channels. The charge redistribution module redistributes the capacitor charges in the basic unit module to achieve power decoupling, which can reduce external components, increase the system power density, achieve high power transmission efficiency, and ensure the independence of each output at the same time. This topology can be flexibly constructed by selecting an appropriate number of basic units N according to conditions such as input voltage requirements, output channel number, conversion ratio, switch voltage withstand, capacitor voltage withstand, and passive device size, so as to adapt to different application requirements. This flexible design method makes this converter widely applicable in a variety of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of a multi-inductor multi-output DC voltage converter provided by an embodiment of the present application;

[0026] Figure 2 is a schematic step flow diagram of a control method for a multi-inductor multi-output DC voltage converter provided by an embodiment of the present application;

[0027] Figure 3 is a schematic structural diagram of a basic unit of a hybrid topology provided by an embodiment of the present application;

[0028] Figure 4 It is a schematic diagram of the working state of the basic unit of the hybrid topology structure provided by the embodiment of the present application;

[0029] Figure 5 It is a schematic diagram of the structure of the N+1:1 scalable N-output hybrid topology buck converter provided by the embodiment of the present application;

[0030] Figure 6 It is a schematic diagram of the structure of the 3:1 dual-output hybrid topology buck converter provided by the embodiment of the present application;

[0031] Figure 7 It is a schematic diagram of the working process of the 3:1 dual-output hybrid topology buck converter provided by the embodiment of the present application;

[0032] Figure 8 It is a schematic diagram of the voltage waveform of the key nodes of the 3:1 dual-output hybrid topology buck converter provided by the embodiment of the present application;

[0033] Figure 9 It is a schematic diagram of the current distribution ratio of the 3:1 dual-output hybrid topology buck converter provided by the embodiment of the present application;

[0034] Figure 10 It is a schematic diagram of the working principle of the current distribution of the 3:1 dual-output hybrid topology buck converter provided by the embodiment of the present application;

[0035] Figure 11 It is a schematic diagram of the test of the key waveforms in the steady state of the 3:1 dual-output buck converter provided by the embodiment of the present application;

[0036] Figure 12 It is a schematic diagram of the test of the key waveforms in the steady state of the 5:1 four-output buck converter provided by the embodiment of the present application;

[0037] Figure 13 It is a schematic diagram of the visualization of the efficiency results of the dual-output buck converter provided by the embodiment of the present application;

[0038] Figure 14 It is a schematic diagram of the visualization of the efficiency results of the four-output buck converter provided by the embodiment of the present application. Specific embodiments

[0039] To make the objectives, technical solutions and advantages of this application more clear and understandable, the following further elaborates on this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used to explain this application and not to limit it. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the embodiments of this application. They are merely examples of systems and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0040] It can be understood that the terms "first", "second", etc. used in this application may be used herein to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if", "when" as used herein may be interpreted as "when...", "while...", or "in response to determining".

[0041] The terms "at least one", "multiple", "each", "any one", etc. used in this application, at least one includes one, two or more than two, multiple includes two or more than two, each refers to each of the corresponding multiple, and any one refers to any one of the multiple.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0043] First of all, it should be noted that with the promotion of emerging technologies such as artificial intelligence, data centers and cloud computing have developed rapidly, the number of servers has increased sharply, resulting in a continuous increase in overall power consumption. At the same time, multiple low-voltage power rails at the load end are crucial for high energy efficiency and refined power management. As the core of the power management unit, in order to transmit greater power and reduce transmission losses, a DC-DC converter usually requires a relatively high input voltage. Therefore, the market urgently needs a high-efficiency and high-density buck converter with a high input voltage (V IN ), a large voltage conversion ratio (VCR, defined as V IN / V OUT ) and multiple output channels.

[0044] In view of this, in the embodiments of the present application, a multi-inductor multi-output DC voltage converter is provided, which can be flexibly constructed according to conditions such as input voltage requirements, number of output channels, conversion ratio, switch withstand voltage, capacitor withstand voltage, and passive device size, so as to adapt to different application requirements. And maintain efficient and stable performance under different load conditions.

[0045] Referring to Figure 1 , Figure 1 is a structural diagram of a multi-inductor multi-output DC voltage converter provided by an embodiment of the present invention. Referring to Figure 1 , the converter includes a plurality of basic unit modules and a charge redistribution module. The plurality of basic unit modules are connected in series, and the plurality of basic unit modules are all connected to the charge redistribution module, where:

[0046] The basic unit module is used to reduce the switch withstand voltage and provide the output voltage;

[0047] Specifically, the basic unit module includes a first power switch M Ai , a second power switch M Bi , a third power switch M Ci , a first flying capacitor C Fi , a first DC capacitor C DCi and a first inductor L i . The second end of the first DC capacitor is connected to the first end of the first power switch and connected to the high-level voltage UP. The second end of the first power switch, the first end of the second power switch and the first end of the first flying capacitor are connected to the second conversion node V Yi . The second end of the first flying capacitor, the first end of the third power switch and the first end of the first inductor are connected to the first conversion node V Xi . The first end of the first DC capacitor is grounded, the second end of the third power switch is grounded, the second end of the second power switch is connected to the low-level voltage DOWN, and the second end of the first inductor is used as the output end of the basic unit module. Among them, the first power switch, the second power switch and the third power switch are used to switch the connection mode of the capacitor and the inductor, the first flying capacitor is used for energy transmission, the first DC capacitor is used to provide a voltage source for the intermediate level, decouple the duty cycle of the two cascaded basic unit modules before and after, and the first inductor is used to filter the switch node to obtain the output voltage.

[0048] In this embodiment, as Figure 3 and Figure 4 shown, the basic unit of the multi-output converter consists of three power switches M Ai , M Bi , M Ci and three energy storage elements, specifically including: the power switch is used to switch the connection mode of the capacitor and the inductor to realize power transmission; a flying capacitor C Fi, participate in the energy transfer; a DC capacitor C DCi , can be regarded as a voltage source providing an intermediate level for decoupling the duty cycles of the two cascaded stages before and after; and an inductor L i , filter the switching node to obtain the output voltage. During the magnetization period of the inductor L i , M Ai conducts, and L i and C Fi are charged from the upstream basic unit. During the demagnetization period of the inductor, C Fi transfers the charge stored during the magnetization period to the downstream basic unit through the switches M Bi and M Ci . The voltage of the conversion node V Yi switches between the two node levels of UP and DOWN. The magnetization period is the UP node level, and the demagnetization period is the DOWN node level. The voltage swing of the conversion node V Xi is equal to UP–DOWN. The level during the magnetization period is UP–DOWN, and the level during the demagnetization period is 0. This operating mode makes the power of each output correlated because the charge extracted by the output i will be evenly transferred to the output i + 1.

[0049] The charge redistribution module is used to redistribute the capacitor charge in the basic unit module to achieve power decoupling.

[0050] Specifically, the charge redistribution module includes a number of switching transistors M Ri and a second DC capacitor C CP . The second end of the second DC capacitor is grounded, and the first end of the second DC capacitor is connected to the second ends of a number of switching transistors and the low-level voltage of the first basic unit module. The first ends of a number of switching transistors are respectively connected to the first conversion nodes of a number of basic unit modules.

[0051] In this embodiment, the introduced charge redistribution module uses the DC capacitor (C CP ) as a charge pool and redistributes the remaining charge on V Ri to each channel output through the switch M R , effectively solving this problem. Therefore, at the output, each basic unit can provide multiple independent outputs in parallel. Specifically, during the magnetization period, an auxiliary path is added through M Ri to decouple the output current (I oi ) and the current in the flying capacitor C Fi (I CFi ). If the load of output i is much larger than that of other channels, M Ri can perform charge redistribution on output channel i (I Ri ). Therefore, C FiLess charge is transferred to the downstream unit with a lighter load, and less charge from the upstream unit is required, thus achieving charge balance for all flying capacitors. Otherwise, when the load of unit i is lighter, the charge redistribution current (I Ri ) can also be negative.

[0052] In summary, the embodiment of the present invention consists of several basic units and a charge redistribution module. Each basic unit is responsible for reducing the switch breakdown voltage and providing an output, and the charge redistribution module is responsible for redistributing the capacitor charges in the basic units, thereby achieving power decoupling. As Figure 1 shown. Each basic unit is connected in series to reduce the voltage stress on the switches and inductors, enhancing the ability to support higher input voltages and more output channels. At the same time, this structure shares the flying capacitors in each basic unit. To handle the problem that the output power of each channel is not independent due to the shared flying capacitors, a charge redistribution module is introduced. Therefore, this connection method reduces external components, increases the system power density, and ensures the independence of each output. Under two-phase period operation, when the number of output channels is N, the voltage stress faced by all power switches is V IN / (N + 1). Therefore, low-voltage devices with low parasitic effects can be used to improve the system conversion efficiency. Therefore, the duty cycle D i of each channel is only determined by the input voltage (V IN ) and the output voltage (V oi ) of this channel, and the expression is D i = V oi / [(N + 1)×V IN . The voltage stress of the conversion node V SW is reduced to 1 / (N + 1) times that of the traditional inductor-type buck converter. Therefore, we call it an N-output buck converter with a ratio of (N + 1):1.

[0053] Furthermore, it should be further noted that, as Figure 5 shown, the upstream end (UP) of each basic unit is sequentially connected to the downstream end (DOWN), and the downstream end of the last basic unit is connected to port 0 C CP of the charge redistribution module. Then, port 1 V X1 of basic unit 1 is connected to port 1 of the charge redistribution module, port 2 V X2 of basic unit 2 is connected to port 2 of the charge redistribution module, and so on. Port N V XN of basic unit N is connected to port N of the charge redistribution module. Using N basic units, a switched-capacitor N-output DC-DC converter with a voltage conversion ratio of (N + 1):1 can be realized.

[0054] For the connection of basic units, the upstream end (UP) of each basic unit is sequentially connected to the downstream end (DOWN) of the next basic unit.

[0055] For the connection of the charge redistribution module, the downstream end (DOWN) of the last basic unit is connected to port 0 (C CP ) of the charge redistribution module. The ports V X1 , V X2 , …, V XN of each basic unit are respectively connected to the corresponding ports 1, 2, …, N of the charge redistribution module.

[0056] Please refer to Figure 2 , this embodiment of the present application also provides a control method for a multi-inductor multi-output DC voltage converter, which can implement the above-mentioned multi-inductor multi-output DC voltage converter. The method includes the following steps:

[0057] S100. According to the input voltage signal, based on the basic unit module, the first inductor is alternately magnetized and demagnetized in a complete cycle to obtain the output current and output voltage at the load end.

[0058] In some specific embodiments, during the magnetization stage of the first inductor, the first power switch in the basic unit module and the switch tube in the charge redistribution module are both in the on state, the second power switch and the third power switch in the basic unit module are in the off state, the first flying capacitor in the basic unit module is connected to the second DC capacitor in the charge redistribution module through the switch tube, and the first DC capacitor in the basic unit module charges the first flying capacitor and the first inductor through the first power switch.

[0059] Among them, for the magnetization period, the voltage swing of the first conversion node is the voltage difference between the high-level voltage UP and the low-level voltage DOWN, and the voltage of the second conversion node is the high-level voltage UP.

[0060] In some specific embodiments, during the demagnetization stage of the first inductor, the first power switch in the basic unit module and the switch tube in the charge redistribution module are both in the off state, the second power switch and the third power switch in the basic unit module are in the on state, the first flying capacitor in the basic unit module disconnects from the first DC capacitor in the basic unit module and the second DC capacitor in the charge redistribution module, the first flying capacitor is in the discharge state, and the first inductor extracts charge from the ground terminal GND through the third power switch.

[0061] Among them, for the demagnetization stage, the voltage of the first conversion node is 0, and the voltage of the second conversion node is the low-level voltage DOWN.

[0062] S200. Obtain the first flying capacitor current, combine the output current and output voltage at the load end, and based on the charge redistribution module, adjust the inductor current and output the adjusted inductor current.

[0063] In some specific embodiments, based on the charge redistribution module, the inductor current is adjusted and then output to the load end, so that the load currents provided by different output channels are completely independent, that is, the load currents of different output channels can be the same or different.

[0064] Perform periodic control on the converter. When the converter enters the steady-state operating state, the steady-state voltage on the first DC capacitor in the first basic unit module of the converter is V DC1 = 2×V IN / (N + 1), the steady-state voltage on the first DC capacitor in the second basic unit module is V DC2 = 3×V IN / (N + 1), the steady-state voltage on the first DC capacitor in the (N - 1)th basic unit module is V DC(N-1) = N×V IN / (N + 1), the steady-state voltage of the first DC capacitor in the Nth basic unit module is V DCN = (N + 1)×V IN / (N + 1);

[0065] The voltage stress of the first flying capacitor in the first basic unit module is V CF1 = 1×V IN / (N + 1), the voltage stress of the first flying capacitor in the second basic unit module is V CF2 = 2×V IN / (N + 1), the voltage stress of the first flying capacitor in the (N - 1)th basic unit module is V CF(N-1) = (N - 1)×V IN / (N + 1), the voltage stress of the first flying capacitor in the Nth basic unit module is V CFN = N×V IN / (N + 1), the steady-state voltage of the second DC capacitor in the charge redistribution module is V R = V IN / (N + 1);

[0066] Wherein, N represents the number of basic units of the converter, that is, the number of output channels, and V IN represents the input voltage.

[0067] Further, taking a dual-output converter as an example, as Figure 6As shown, the topology of the proposed 3:1 dual-output hybrid buck converter is presented. The converter consists of two basic units and a charge redistribution module. The voltage and current regulations of the two output channels are independent of each other, thus providing two non-interfering outputs. Each channel contains two operating periods: an inductor magnetization period and an inductor demagnetization period. As Figure 7 and Figure 8 show the working flow chart of voltage conversion and the waveform diagram of key nodes. Here, i represents the component corresponding to the basic unit i.

[0068] During the first magnetization period, switches M Ai and M Ri are turned on, switches M Bi and M Ci are turned off, the flying capacitor C Fi is charged and connected to the DC capacitor C Ri through M CP ; the DC capacitor C DCi charges the inductor L Ai through M Fi and C i . During the second demagnetization period, switches M Bi and M Ci are turned on, switches M Ai and M Ri are turned off, the flying capacitor C Fi discharges, disconnects from the DC capacitors C DCi , C CP , and the inductor L i draws charge from the ground terminal GND through M Ci .

[0069] In this topology, the presence of the DC capacitor reduces the voltage stress on the power switches. By analyzing the operating states of the channels and applying Kirchhoff's laws, the voltage stress on each switch can be obtained as V IN / 3. The same voltage stress also enables the topology to have the ability to expand. Based on this voltage stress, when the input voltage V IN is 12V, 5V devices can be used, significantly improving the efficiency of the system. In the steady state, the voltage distributions of the capacitors are as follows: the steady-state voltages of the DC capacitors C DC2 , C DC1 and the charge redistribution module C CP are V DC2 = V IN , V D1C = 2×V IN / 3, and V R = V IN / 3; the voltage stresses of the flying capacitors C F2 and C F1 are 2×VIN / 3, V IN / 3. In addition, the switching nodes V X1 and V X2 switch between 0 and V R , and their conduction time = duty cycle (D i ) * period (T swi ) is determined by the operating state of each channel i. Through reasonable voltage distribution and control, this topology can operate stably under different load conditions.

[0070] As Figure 9 shown, it demonstrates the ratio change between the current (I Ri ) provided by the reallocation module and the current (I CFi ) provided by the flying capacitor of the proposed 3:1 dual-output buck converter under different load conditions. Classified and discussed according to different load situations, first is the case where the two output channels are in a balanced load situation, that is, when the load currents of the first output channel and the second output channel are equal; second is the case where the two output channels are in an unbalanced load situation, where the load current of the second output channel is greater than that of the first output channel (or vice versa).

[0071] For the balanced load situation where I O2 = I O1 , there is:

[0072] I O2 = I R2 + I CF2 , I R2 = 0.5 × I CF2

[0073] I O1 = I R1 + I CF1 , I R1 = 0.5 × I CF1

[0074] The load currents of the first and second channels are jointly provided by the current of the flying capacitor and the reallocation module.

[0075] For the unbalanced load situation when I O2 = 2I O1 , there is:

[0076] I O2 = I R2 + I CF2 , I R2 = I CF2

[0077] I O1 = I CF1 , I R1 = 0

[0078] That is, the first channel only passes through the flying capacitor C F1 to provide current, and the current of the second channel is provided jointly by the flying capacitor C F2 and the current of the redistribution module.

[0079] For the unbalanced load condition when I O2 > 2I O1 there is:

[0080] I O2 = I R2 + I CF2 + I R1 , I R2 > I CF2

[0081] I O1 = I CF1 , I R1 < 0

[0082] That is, the excess current of the basic unit 1 flows reversely into the basic unit 2 to provide more charge to meet the larger load demand, indicating that the basic unit 2 reuses the components of the basic unit 1, improving the component utilization rate.

[0083] Taking one of the cases as an example to analyze the working state, when the load current I O2 of the second channel is twice that of the load current I O1 of the first channel, as Figure 10 shown, when the basic unit 1 is in the magnetization period, the switches M A1 and M R1 are turned on, and the switches M B1 and M C1 are turned off. The DC capacitor C DC1 charges the inductor L1 through M A1 and C F1 . The flying capacitor C F1 is charged only by the load current I O1 of the first channel through the inductor L1, that is, the flying capacitor provides the current I CF1 > I O1 . Since I O1 is small, in order to avoid excessive charge transfer to the basic unit 1, C F1 will transfer the excess charge to C R1 or the basic unit 2 through M CP . When the basic unit 2 is in the magnetization period, the switches M A2 and M R2 are turned on, and the switches M B2 and M C2 are turned off. The DC capacitor C DC2 charges through M A2 and C F2Charge the inductor L2, and the load current of the second output channel and the flying capacitor C F2 provide a current relationship of I O2 >I CF2 . At the same time, the DC capacitor C CP or the basic unit 1 supplies more charge to the output channel 2 through M R2 to meet the larger load current I of the second channel O2 . With the help of the charge redistribution module (C CP +M Ri ), the output current of each path is not affected by other channels, realizing the independence of the output current. Even if an output has no load, its capacitive network can be reused by the fully loaded path, thus significantly improving the utilization rate of components.

[0084] From the perspective of voltage, the two output channels can work simultaneously in the magnetization period, or simultaneously in the demagnetization period, or one channel can work in the magnetization period while the other channel works in the demagnetization period. The duty cycle parameters of each output channel are independent of each other, and multi-voltage output can be achieved through differential adjustment to meet the voltage requirements of different loads. The presence of C DCi in each unit allows duty cycle overlap, enabling all inductor currents to rise simultaneously. The independent transient response of each channel ensures a fast transient response for all channels. Flexible working modes and efficient dynamic responses are achieved.

[0085] As Figure 11 shown, it presents a test diagram of the key steady-state waveforms of the proposed 3:1 dual-output buck converter. In this test diagram, the two output channels provide different output voltages, and the variation of the node voltage is consistent with the theoretical analysis results. By comparing the test waveforms with the theoretical predictions, the voltage distribution and performance of this topology in the steady state can be verified, indicating that the system can operate stably as expected and provide the required output voltage.

[0086] The system can be cascaded in any number of stages. For example, in addition to connecting individual basic units together, we can also cascade two dual-output buck converters according to the Figure 5 connection method shown to construct a four-output buck converter. In this configuration, the conversion ratio is 5:1, the voltage stress of the power switch is reduced to V IN / 5, and the voltage swing at the V Xi node is V IN / 5, a 5:1 four-output buck converter is constructed. This means that the system can support higher input voltages, further reduce transmission line losses, and improve overall efficiency. When the input voltage is increased to 24V, this cascaded method enables the power switches to continue using low-voltage devices while supporting higher input voltages and providing four independent output channels. To further verify the scalability of this topology, we connected two 3:1 dual-output buck converter chips on a PCB board to construct a 5:1 four-output buck converter. The test results of the steady-state waveforms are as Figure 12 shown, and the four output channels each provide different voltages. When the input voltage is 24V, the node voltages or voltage swings at each point are all consistent with the theoretical values, which is V IN / 5 = 4.8V, verifying the scalability and stability of this topology in practical applications.

[0087] As Figure 13 well as Figure 14 shown, the efficiency test curves of the dual-output and four-output buck converters at input voltages of 12V and 24V are shown respectively. This figure shows that under the shared switched-capacitor (including flying capacitors and DC capacitors) design, when the output voltage of each output channel is 1.2V and the input voltage increases from 12V to 24V, the peak efficiency only drops by 1.4%. This highlights the excellent scalability of this structure. Expanding to more outputs can support higher input voltages and maintain high system efficiency. This highlights the effectiveness of the design.

[0088] It can be understood that the content in the above method embodiments is applicable to the system embodiments of the present application. The functions specifically implemented by the system embodiments of the present application are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0089] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings. This does not limit the scope of the rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the rights of the embodiments of the present application.

Claims

1. A multi-inductor multi-output DC voltage converter, characterized in that, The converter includes a number of basic unit modules and a charge redistribution module. The number of the basic unit modules are connected in series, and the number of the basic unit modules are all connected to the charge redistribution module, where: The basic unit module is used to reduce the switch withstand voltage and provide an output voltage; The charge redistribution module is used to redistribute the capacitor charges in the basic unit module to achieve power decoupling.

2. The converter according to claim 1, wherein The basic unit module includes a first power switch, a second power switch, a third power switch, a first flying capacitor, a first DC capacitor, and a first inductor. The second end of the first DC capacitor is connected to the first end of the first power switch and connected to a high-level voltage UP. The second end of the first power switch, the first end of the second power switch, and the first end of the first flying capacitor are connected to a second conversion node. The second end of the first flying capacitor, the first end of the third power switch, and the first end of the first inductor are connected to a first conversion node. The first end of the first DC capacitor is grounded. The second end of the third power switch is grounded. The second end of the second power switch is connected to a low-level voltage DOWN. The second end of the first inductor serves as the output end of the basic unit module.

3. The converter according to claim 2, characterized in that, The first power switch, the second power switch, and the third power switch are used to switch the connection mode of the capacitor and inductor. The first flying capacitor is used for energy transfer. The first DC capacitor is used to provide a voltage source with an intermediate level to decouple the duty cycles of the two cascaded basic unit modules before and after. The first inductor is used to filter the switching node to obtain the output voltage.

4. The converter according to claim 2, wherein The charge redistribution module includes a number of power switch tubes and a second DC capacitor. The second end of the second DC capacitor is grounded. The first end of the second DC capacitor is connected to the second ends of the number of power switch tubes and the low-level voltage of the first basic unit module. The first ends of the number of power switch tubes are respectively connected to the first conversion nodes of the number of basic unit modules.

5. A control method for a multi-inductor multi-output DC voltage converter, characterized in that, The method includes the following steps: According to the input voltage signal, based on the basic unit module, the first inductor is alternately magnetized and demagnetized in a complete cycle to obtain the load terminal output current and the load terminal output voltage; Obtain the first flying capacitor current and combine the load terminal output current and the load terminal output voltage, and based on the charge redistribution module, adjust the inductor current to output the adjusted inductor current.

6. The method according to claim 5, wherein For the magnetization stage of the first inductor, the first power switch in the basic unit module and the switch tube in the charge redistribution module are both in the on state. The second power switch and the third power switch in the basic unit module are in the off state. The first flying capacitor in the basic unit module is connected to the second DC capacitor in the charge redistribution module through the switch tube. The first DC capacitor in the basic unit module charges the first flying capacitor and the first inductor through the first power switch.

7. The method according to claim 5, wherein For the demagnetization stage of the first inductor, the first power switch in the basic unit module and the switching transistor in the charge redistribution module are both in the off state, the second power switch and the third power switch in the basic unit module are in the on state, the first flying capacitor in the basic unit module disconnects from the first DC capacitor in the basic unit module and the second DC capacitor in the charge redistribution module, the first flying capacitor is in the discharge state, and the first inductor extracts charge from the ground terminal GND through the third power switch.

8. The method according to claim 5, characterized in that, It further includes: For the magnetizing period, the voltage of the first conversion node is the high-level voltage UP minus the low-level voltage DOWN, and the voltage of the second conversion node is the high-level voltage UP; For the demagnetization stage, the voltage of the first conversion node is 0, and the voltage of the second conversion node is the low-level voltage DOWN.

9. The method according to claim 5, characterized in that, Based on the charge redistribution module, the inductor current is adjusted so that the currents output by different output channels are independent of each other.

10. The method according to claim 5, wherein It further includes: The converter is periodically controlled. When the converter enters the steady-state operating state, the steady-state voltage across the first DC capacitor in the first basic unit module of the converter is V DC1 = 2×V IN / (N + 1), the steady-state voltage across the first DC capacitor in the second basic unit module is V DC2 = 3×V IN / (N + 1), the steady-state voltage across the first DC capacitor in the (N - 1)th basic unit module is V DC(N-1) = N×V IN / (N + 1), the steady-state voltage across the first DC capacitor in the Nth basic unit module is V DCN = (N + 1)×V IN / (N + 1); The voltage stress of the first flying capacitor in the first basic unit module is V CF1 = 1×V IN / (N + 1), the voltage stress of the first flying capacitor in the second basic unit module is V CF2 = 2×V IN / (N + 1), the voltage stress of the first flying capacitor in the (N - 1)th basic unit module is V CF(N-1) = (N - 1)×V IN / (N + 1), the voltage stress of the first flying capacitor in the Nth basic unit module is V CFN = N×V IN / (N + 1), the steady-state voltage of the second DC capacitor in the charge redistribution module is V R = V IN / (N + 1); Among them, N represents the number of basic units of the converter, that is, the number of output channels, and V IN represents the input voltage.

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