A multi-level multi-stage dc power supply architecture based on switched capacitor

Abstract

The application discloses a multi-stage multi-level DC power supply architecture based on a switched capacitor, which comprises an input source, a first power conversion part, a switching network and a second power conversion part, wherein the first power conversion part is a converter structure with a fixed conversion ratio, and contains a switched capacitor circuit with a stage number n; the switching network is a circuit structure with a multi-port input and a double-port output; and the second power conversion part is a three-port circuit with a double-port input and a single-port output. The power supply architecture can reduce the swing of a switching point, reduce the volume of an inductor, improve power density and efficiency, and is suitable for power supply applications in the field of modern computing SOC.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a multi-stage and multi-level DC power supply architecture based on switched capacitors. Background Art

[0002] In recent years, modern computing SOCs have typically required high output currents at output voltages of 1V or less, posing significant challenges in powering the CPU. Fully integrated voltage regulators are often used to locally reduce the voltage to alleviate current pressure. Implementing a high-efficiency DC-DC converter with a wide output voltage range and fast transient response remains a challenge for modern computing SOCs.

[0003] Reference A, "93.8% Peak Efficiency, 5V Input, 10A Max ILOAD Flying Capacitor Multilevel Converter in 22nm CMOS Featuring Wide Output Voltage Range and Flying Capacitor Precharging" (2019 IEEE International Solid-State Circuits Conference (ISSCC), 2019), uses a 22nm process to implement a four-level flying capacitor converter topology. The topology employs three cascaded, complementary switch pairs. The control circuit utilizes a start-up gate driver, a level shifter, and a three-phase PWM, with the controller implemented on an FPGA. This topology ultimately achieves a maximum output current of 10A. However, in this multi-level structure, the voltage across the flying capacitor requires additional control to balance it. Furthermore, achieving this topology and performance requires specialized advanced processes.

[0004] The paper "12A Imax, Fully Integrated Multi-Phase Voltage Regulator with 91.5% Peak Efficiency at 1.8 to 1V, Operating at 50MHz and Featuring a Digitally Assisted Controller with Automatic Phase Shedding and Soft Switching in 4nm Class FinFET CMOS" (2022 IEEE International Solid-State Circuits Conference (ISSCC), 2022) uses a 4nm process to implement a four-phase interleaved parallel buck converter topology. By detecting the load current and varying operating conditions, the number of operating phases is dynamically adjusted to achieve improved efficiency and reduced device stress. However, this multi-phase interleaved parallel structure requires a large number of switches and control signals to control the different phases. Furthermore, this topology requires advanced CMOS technology, and the inductors in the four-phase interleaved parallel structure also require specialized implementation methods. Summary of the Invention

[0005] In view of the challenges of high-efficiency and wide-range voltage output in modern computing SOCs, the present invention provides a multi-stage, multi-level DC power supply architecture based on switched capacitors. This power supply architecture consists of a first-level scalable fixed-ratio switched capacitor structure, a first-level switch network structure, and a first-level scalable adjustable-ratio switched capacitor structure. The fixed-ratio switched capacitor circuit achieves multi-power rail output through multiple switching tubes and multiple capacitors. Based on the output voltage and load current requirements, the power rails in the switch network can be flexibly adjusted, thereby flexibly adjusting the output voltage range and expanding the model, making it suitable for power supply applications in computing SOCs and other fields.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention first proposes a multi-stage multi-level DC power supply architecture based on switched capacitors, comprising an input source, a first power conversion part connected to the input source, a second power conversion part, and a switch network located between the first power conversion part and the second power conversion part;

[0008] The first power conversion section is a converter structure with a fixed conversion ratio. The first power conversion section includes 2n switching transistors, 2n-2 capacitors, and a plurality of output ports. The i-1th capacitor is connected across the drain of the i-th switching transistor and the source of the i+1th switching transistor, where i≠1 and i≠2n. Thus, power rails with a fixed voltage difference are formed across each capacitor. The high and low voltage levels of these power rails are connected to the switching network as the output voltages of the multi-port.

[0009] The switch network includes multiple input ports and two output ports; wherein the multiple input ports are connected to multiple power rails formed by the first power conversion part, and the output ports are connected to the second power conversion part; the switch network provides a gating function, selecting different power rails to provide to the subsequent second power conversion part;

[0010] The second power conversion part is a converter structure with an adjustable conversion ratio; the second power conversion part includes an input port, an output port, several high-side power tubes and several low-side power tubes; the input port of the second power conversion part is connected to the output port of the switching network, and the output port is connected to the external load; the high-side power tube and the low-side power tube adjust the output voltage and the conversion ratio.

[0011] As a preferred embodiment of the present invention, 2n switching tubes are numbered in sequence; the timing of the driving signals of the odd-numbered switching tubes is consistent, so that the odd-numbered switching tubes are turned on at the same time; the timing of the driving signals of the even-numbered switching tubes is consistent, so that the even-numbered switching tubes are turned on at the same time; the two groups of switching tubes are turned on alternately and the on-time is constant.

[0012] As a preferred solution of the present invention, the first power conversion part can generate multiple groups of power rails with different absolute voltages and the same relative voltage difference as inputs of the switching network through multiple capacitors.

[0013] As a preferred solution of the present invention, the switch network controls the on and off of the switch tube through different external control signals, thereby selecting different power rails to be transmitted to the second power conversion part.

[0014] As a preferred solution of the present invention, the switch network can realize voltage output in different ranges by selecting different power rails and transmit the voltages to the second power conversion part.

[0015] As a preferred embodiment of the present invention, the second power conversion portion controls the conduction and shutdown of the high-side power tube and the low-side power tube by adjusting the power tube control signal to provide the output voltage and load current required by the load. The second power conversion portion can be implemented using a variety of different circuit forms.

[0016] As a preferred solution of the present invention, the second power conversion part adopts a multi-channel adjustable output voltage step-down converter, which can reduce the stress of the power tube and increase the load current.

[0017] As a preferred embodiment of the present invention, the first power conversion section and the second power conversion section can be cascaded in multiple stages. The multi-stage cascade expansion means that the power rail output by the first power conversion section can be used as the input port to cascade another first power conversion section, thereby generating more power rails, and the second power conversion section is similar.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The multi-stage, multi-level DC power supply architecture based on switched capacitors proposed in the present invention uses a ladder circuit structure in the first power conversion part to generate a stable power rail with different absolute voltages and the same relative voltage difference. The high and low levels of the power rail are selected in the switching network and connected to the input port of the second power conversion part. The second power conversion part adopts a converter architecture with adjustable conversion ratio to ultimately provide the voltage signal to the load. Conventional power conversion circuits can only provide 0-V in The power rail has a large swing amplitude, and the overall swing amplitude is large; the multi-stage multi-level DC power supply architecture based on switched capacitors proposed in the present invention provides different power rails in the first power conversion part to supply power to the second power conversion part, which can effectively reduce the swing amplitude of the power rail, and then reduce the swing amplitude of the switch point of the second-stage power conversion part, thereby reducing the volume of the inductor, and ultimately improving the overall power density and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a connection diagram of a multi-stage and multi-level DC power supply architecture system based on switched capacitors according to an embodiment of the present invention.

[0021] Figure 2 middle Figure 2 (a) is a circuit diagram of an n-stage multi-port first power conversion part according to an embodiment of the present invention. Figure 2 (b) is a circuit diagram of a multi-port switch network according to an embodiment of the present invention.

[0022] Figure 3 middle Figure 3 (a) is a circuit diagram of a second power conversion portion including a high-side power transistor and a low-side power transistor according to an embodiment of the present invention; Figure 3 (b) Figure 3 (a) is a circuit diagram of the second power conversion part in which the structure is a basic unit and multiple basic units are connected in parallel.

[0023] Figure 4 middle Figure 4(a) is a circuit diagram of a second power conversion portion having four different power transistors according to an embodiment of the present invention; Figure 4 (b) Figure 4 (a) is a circuit diagram of the second power conversion part in which the structure is a basic unit and multiple basic units are connected in parallel.

[0024] Figure 5 For the present invention Figure 4 (a) shows the logic control timing diagram of the second power conversion part circuit.

[0025] Figure 6 For the present invention Figure 4 (a) shows the key signal waveforms of the second power conversion circuit. DETAILED DESCRIPTION

[0026] The present invention will be further described and illustrated below in conjunction with specific embodiments. The embodiments are merely illustrative of the present disclosure and do not limit its scope. The technical features of the various embodiments of the present invention may be combined accordingly, provided that there is no conflict between them.

[0027] like Figure 1 As shown, a multi-stage multi-level DC power supply architecture based on switched capacitors according to an embodiment of the present invention includes an input source, a multi-port first power conversion part, a three-port second power conversion part, and a switch network structure. The positive pole of the input source is connected to port A of the first power conversion part, the negative pole of the input source is connected to port B of the first power conversion part, and the other ports of the first power conversion part are connected to the switch network. The output ports A' and B' of the switch network are connected to the second power conversion part. The third port C' of the second power conversion part is connected to an external load, and another port of the external load is connected to the negative pole of the input source.

[0028] like Figure 2 As shown in (a), in a specific embodiment of the present invention, the n-stage multi-port first power conversion part includes 2n switching tubes (Q1, Q2...Q 2n ), 2n-2 capacitors (C1, C2…C 2n-2 ) and multiple port outputs, with 2n-2 capacitors connected across the drain of the i-th switch and the source of the i+1-th switch, where i ≠ 1 and i ≠ 2n. This architecture generates multiple power rails with fixed voltage differences, meaning that a fixed voltage difference is formed across each capacitor. The high and low voltage levels of these power rails serve as the output voltages of the multiple ports and are connected to the switch network. The 2n switches are Q1, Q2, ..., Q 2n ; 2n-2 capacitors are C1, C2...C 2n-2 ; The drains of the switching tubes are VH1, VH2…VH 2n-2; The source electrodes of the switching tubes are VL1, VL2…VL 2n-2 .

[0029] like Figure 2 As shown in Figure (a), in a more preferred embodiment of the present invention, the timing of the drive signals for the odd-numbered switches in the first power conversion section is consistent, so that the odd-numbered switches are turned on simultaneously; the timing of the drive signals for the even-numbered switches is consistent, so that the even-numbered switches are turned on simultaneously. The two groups of switches are turned on alternately and the on-time is constant.

[0030] like Figure 2 As shown in Figure (b), in a specific embodiment of the present invention, a multi-port switch network includes two parts: a high-side power rail gating part and a low-side power rail gating part. The switch network uses different control signals to control the on and off of the switches through an external controller, thereby gating the high-side power rail and the low-side power rail.

[0031] The second power conversion part is a converter structure with adjustable conversion ratio, which can be realized by a variety of different circuit forms. The specific implementation methods can be: Figure 3 (a) Figure 3 (b) Figure 4 (a) and Figure 4 (b) and other methods.

[0032] like Figure 3 As shown in (a), in a specific embodiment of the present invention, the four-port second power conversion part includes a high-side power tube and a low-side power tube. The high-side power rail and the low-side power rail in the switch network circuit are connected to the high-side power tube and the low-side power tube as input terminals respectively. The second power conversion part controls the conduction and shutdown of the power tube with a control signal to provide the output voltage and load current required by the load. Figure 3 (b) shows another specific embodiment of the present invention, the four-port second power conversion part includes multiple high-side power tubes and multiple low-side power tubes. Figure 3 The structure in (a) represents a basic unit, with multiple units connected in parallel. The high-side and low-side power rails in the switching network circuit serve as inputs to the high-side and low-side power transistors, respectively. Control signals turn the power transistors on and off, generating the output voltage and load current required by the load. Using multiple phases of high-side and low-side switching transistors can improve overall load capacity.

[0033] Figure 4 (a) is a four-port second power conversion circuit diagram according to an embodiment of the present invention, which includes four different power transistors. The control signals for these four power transistors are: Q1 has a control signal with a duty cycle of D; Q2 has a control signal that is half a cycle out of phase with Q1; Q3 has a control signal that is the opposite of Q2; and Q4 has a control signal that is the opposite of Q1. Figure 5 The control timing diagram for the four signals Q1-Q4 is shown. Based on the volt-second balance of inductor L, it can be determined that when the duty cycle D is less than 0.5, the voltage at the switch point SW varies between 0 and 1 / 2VIN, and the output voltage VOUT is DVIN. When the duty cycle D is greater than 0.5, the voltage at the switch point SW varies between 1 / 2VIN and VIN, and the output voltage VOUT is DVin. Figure 6 (a) and Figure 6 (b) The voltage at the switching point SW and the current on the inductor L are respectively shown when the duty cycle D<0.5 and the duty cycle D>0.5. Figure 4 (b) is a diagram of a four-port second power conversion circuit according to an embodiment of the present invention. Figure 4 The structure in (b) is equivalent to Figure 4 The structure in (a) is a basic unit. Multiple basic units are connected in parallel. This structure of multiple basic units in parallel can improve the overall load capacity.

[0034] In summary, the present invention discloses a multi-stage, multi-level DC power supply architecture based on switched capacitors. A ladder circuit structure is employed in the first power conversion section, forming a power rail with a fixed voltage difference across each capacitor. The high and low levels of the power rail are selected in the switching network and connected to the input port of the second power conversion section. A converter architecture with an adjustable conversion ratio is employed in the second power conversion section, ultimately providing a voltage signal to the load. The present invention discloses a multi-stage, multi-level DC power supply architecture based on switched capacitors, which can flexibly adjust the power rails in the switching network and thus the output voltage range, according to the output voltage and load current requirements.

[0035] The above examples specifically illustrate and describe exemplary implementations of the present invention. The above embodiments are only used to illustrate the technical solutions of the present invention so that those skilled in the art can understand and apply the present invention. The present invention is not limited to the detailed structures, configuration methods, or implementations described herein. It should be noted that it is obvious that those skilled in the art can easily make various modifications to the above embodiments, or replace some or all of the technical features of the present invention with equivalents, or apply the general principles described herein to other embodiments without creative work. Modifications, improvements, or equivalent replacements of technical features of the present invention should all fall within the scope of protection of the present invention.

Claims

1. A multi-stage multi-level DC power supply architecture based on switched capacitors, characterized in that: The invention comprises an input source, a first power conversion part connected to the input source, a second power conversion part, and a switch network located between the first power conversion part and the second power conversion part; The first power conversion section is a converter structure with a fixed conversion ratio. The first power conversion section includes 2n switching transistors, 2n-2 capacitors, and a plurality of output ports. The i-1th capacitor is connected across the drain of the i-th switching transistor and the source of the i+1th switching transistor, where i≠1 and i≠2n. Thus, power rails with a fixed voltage difference are formed across each capacitor. The high and low voltage levels of these power rails are connected to the switching network as the output voltages of the multi-port. The switch network includes multiple input ports and two output ports; the multiple input ports are connected to multiple power rails formed by the first power conversion part, and the output ports are connected to the second power conversion part; the switch network provides a gating function, selecting different power rails to provide to the subsequent second power conversion part; The second power conversion part is a converter structure with an adjustable conversion ratio; the second power conversion part includes an input port, an output port, several high-side power tubes and several low-side power tubes; the input port of the second power conversion part is connected to the output port of the switching network, and the output port is connected to the external load; the high-side power tube and the low-side power tube are used to adjust the output voltage.

2. The multi-stage multi-level DC power supply architecture based on switched capacitors according to claim 1, characterized in that: The 2n switching tubes are numbered in sequence, wherein the timing of the driving signals of the odd-numbered switching tubes is consistent, so that the odd-numbered switching tubes are turned on at the same time; the timing of the driving signals of the even-numbered switching tubes is consistent, so that the even-numbered switching tubes are turned on at the same time; the two groups of switching tubes are turned on alternately and the on-time is constant.

3. The multi-stage multi-level DC power supply architecture based on switched capacitors according to claim 1, characterized in that: The first power conversion part can generate multiple groups of power rails with different absolute voltages and the same relative voltage difference as inputs of the switching network through multiple capacitors.

4. The multi-stage multi-level DC power supply architecture based on switched capacitors according to claim 1, characterized in that: The switch network controls the on and off of the switch tubes through different external control signals, thereby selecting different power rails.

5. The multi-stage multi-level DC power supply architecture based on switched capacitors according to claim 1, characterized in that: The switch network can realize voltage output in different ranges by selecting different power rails and transmit the voltages to the second power conversion part.

6. The multi-stage multi-level DC power supply architecture based on switched capacitors according to claim 1, characterized in that: The second power conversion part controls the on and off of the high-side power tube and the low-side power tube by adjusting the power tube control signal, thereby providing the output voltage and load current required by the load.

7. The multi-stage multi-level DC power supply architecture based on switched capacitors according to claim 1, characterized in that: The second power conversion part can be implemented in a variety of different circuit forms.

8. The multi-stage and multi-level DC power supply architecture based on switched capacitors according to claim 7, characterized in that: The second power conversion part adopts a multi-channel adjustable output voltage step-down converter, which can reduce the stress of the power tube and increase the load current.

9. The multi-stage and multi-level DC power supply architecture based on switched capacitors according to claim 1, characterized in that: The first power conversion part and the second power conversion part can be expanded in multi-stage cascade.

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