Direct current conversion circuit and direct current conversion device

Abstract

A DC conversion circuit and a DC conversion device relate to a power converter. The direct current conversion circuit comprises a shared flying capacitor module, a step-down conversion module and a circuit switching module; the shared flying capacitor module comprises a first power switch group and a shared flying capacitor, and the first power switch group responds to the first control signal and controls the shared flying capacitor to be connected with the input voltage or controls the current of the shared flying capacitor to flow back to the ground; the step-down conversion module comprises at least two step-down conversion circuits which work in parallel; each step-down conversion circuit comprises a second power switch group, a flying capacitor and a power inductor; the second power switch group responds to the second control signal to be switched on and off so as to charge or discharge the flying capacitor and magnetize or demagnetize the power inductor; and the circuit switching module responds to the first control signal, connects the shared flying capacitor module with a step-down conversion circuit set in the step-down conversion module, and is used for charging or discharging the shared flying capacitor.

Description

Technical Field

[0001] The present invention relates to a power converter, and more particularly to a DC conversion circuit and a DC conversion device. Background Art

[0002] Nowadays, 12V power rails are widely used in processors, DDR memories, and data centers. However, many of these functional modules require low-voltage power rails of 1.8V to 0.8V for power supply. Please refer to Figure 1 , in a processor system, a 1.8V power rail is required for analog modules, and a 0.85V power rail is required for the DDR core. Therefore, a multi-output high-voltage conversion ratio DC-DC converter that converts 12V input to 1.8V to 0.8V output is currently needed.

[0003] Hybrid architecture DC-DC converters combine the advantages of capacitors and inductors. In applications with high voltage conversion ratios, they can still achieve high power density and high power conversion efficiency. The dual buck (DSD) converter is a basic and popular solution. For traditional dual buck converters, two power inductors provide all the output current, resulting in relatively large DC resistance (DCR) losses of the inductors. In the structure of the DSD dual-output converter, continuous energy delivery and reduction of inductor current are achieved, but it has a cross-regulation problem and still requires additional power transistors to create new power paths. In the buck-type (2PHB) converter with a dual-path hybrid architecture, an additional current path is added to reduce the average current of the inductor, and the flying capacitor only maintains the output voltage. However, the limited duty cycle is still a problem for 2PHB. In the buck-type (2L4PHB) converter with a dual-inductor four-path hybrid architecture, it inherits the advantages of DSD and 2PHB, further reducing the voltage stress of the power transistors, increasing the duty cycle, and adding output current paths to reduce the DCR losses of the inductors. However, 2L4PHB has only one output and requires many additional components to create new power paths. In the structure of the multi-output switched-capacitor buck (SCB) converter, the DC flying capacitor is shared among channels, reducing the voltage gain of the power transistors. Therefore, low-voltage transistors with better performance can be used, and this structure has no cross-regulation effect. However, it still requires four chips and additional flying capacitors to achieve four-way output and corresponding functions. Summary of the Invention

[0004] The main technical problem to be solved by the present invention is to provide a DC conversion circuit with multi-output and high power conversion efficiency and its corresponding DC conversion device.

[0005] According to a first aspect, in one embodiment, a DC conversion circuit is provided, including a shared flying capacitor module, a buck conversion module, and a circuit switching module;

[0006] The shared flying capacitor module includes a first power switch group and a shared flying capacitor. The first power switch group responds to a first control signal to control the connection of the shared flying capacitor to the input voltage or control the current of the shared flying capacitor to flow back to the ground.

[0007] The buck conversion module includes at least two buck conversion circuits operating in parallel. Each buck conversion circuit includes a second power switch group, a flying capacitor, and a power inductor. The second power switch group turns on and off in response to a second control signal to charge or discharge the flying capacitor and magnetize or demagnetize the power inductor.

[0008] The circuit switching module is connected between the buck conversion module and the shared flying capacitor module. The circuit switching module responds to the first control signal to connect the shared flying capacitor module to a set buck conversion circuit in the buck conversion module for charging or discharging the shared flying capacitor.

[0009] Wherein, the frequency of the second control signal is greater than the frequency of the first control signal.

[0010] In one embodiment, the first power switch group includes switch S 1 and switch S 6 , and the shared flying capacitor is flying capacitor C F0 ; The first end of switch S 1 is connected to the input voltage, the second end of switch S 1 is connected to the first end of capacitor C F0 , the second end of flying capacitor C F0 is connected to the first end of switch S 6 , and the second end of switch S 6 is grounded.

[0011] In one embodiment, the circuit switching module includes a first switching circuit and a second switching circuit;

[0012] The circuit switching module turns on the first switching circuit in response to the first control signal, and the shared flying capacitor discharges;

[0013] Or,

[0014] The circuit switching module turns on the second switching circuit in response to the first control signal, and the shared flying capacitor charges;

[0015] Wherein, the first switching circuit and the second switching circuit work alternately.

[0016] In one embodiment, the buck conversion module includes four buck conversion circuits operating in parallel: a first buck conversion circuit, a second buck conversion circuit, a third buck conversion circuit, and a fourth buck conversion circuit;

[0017] The first switching circuit includes a first sub-switching circuit, a second sub-switching circuit, a third sub-switching circuit, and a fourth sub-switching circuit;

[0018] The second switching circuit includes a fifth sub-switching circuit, a sixth sub-switching circuit, a seventh sub-switching circuit, and an eighth sub-switching circuit;

[0019] The first sub-switching circuit and the fifth sub-switching circuit are connected to the first buck conversion circuit; the second sub-switching circuit and the sixth sub-switching circuit are connected to the second buck conversion circuit; the third sub-switching circuit and the seventh sub-switching circuit are connected to the third buck conversion circuit; the fourth sub-switching circuit and the eighth sub-switching circuit are connected to the fourth buck conversion circuit.

[0020] In one embodiment, the second power switch group of the first buck conversion circuit includes switch S 2 and switch S 3 , the flying capacitor of the first buck conversion circuit is flying capacitor C F1 , and the power inductor of the first buck conversion circuit is inductor L 1 ;

[0021] The first end of switch S 2 is connected to the first end of flying capacitor C F1 , the second end of flying capacitor C F1 is connected to the first end of switch S 3 , the second end of switch S 2 is used to output voltage, the second end of switch S 2 is also connected to the first end of inductor L 1 , the second end of inductor L 1 is connected to the first end of switch S 3 , and the second end of switch S 3 is grounded;

[0022] The second power switch group of the second buck conversion circuit includes switch S 4 and switch S 5 , the flying capacitor of the second buck conversion circuit is flying capacitor C F2 , and the power inductor of the second buck conversion circuit is inductor L 2 ;

[0023] The first end of switch S 4 is connected to the first end of flying capacitor C F2 , the flying capacitor C F2The second end of [component] is connected to switch S 5 The first end of [component], said switch S 4 The second end of [component] is used to output voltage, said switch S 4 The second end of [component] is also connected to inductor L 2 The first end of [component], said inductor L 2 The second end of [component] is connected to switch S 5 The first end of [component], said switch S 5 The second end of [component] is grounded;

[0024] The second power switch group of the third buck conversion circuit includes switch S 7 and switch S 8 The flying capacitor of the third buck conversion circuit is flying capacitor C F3 The power inductor of the third buck conversion circuit is inductor L 3 ;

[0025] The first end of said switch S 7 is connected to the first end of flying capacitor C F3 The first end of [component], said flying capacitor C F3 The second end of [component] is connected to the first end of switch S 8 The first end of [component], said switch S 7 The second end of [component] is used to output voltage, said switch S 7 The second end of [component] is also connected to inductor L 3 The first end of [component], said inductor L 3 The second end of [component] is connected to the first end of switch S 8 The first end of [component], said switch S 8 The second end of [component] is grounded;

[0026] The second power switch group of the fourth buck conversion circuit includes switch S 9 and switch S 10 The flying capacitor of the fourth buck conversion circuit is flying capacitor C F4 The power inductor of the fourth buck conversion circuit is inductor L 4 ;

[0027] The first end of said switch S 9 is connected to the first end of flying capacitor C F4 The first end of [component], said flying capacitor C F4 The second end of [component] is connected to the first end of switch S 10 The first end of [component], said switch S 9 The second end of [component] is used to output voltage, said switch S 9 The second end of [component] is also connected to inductor L 4 The first end of [component], said inductor L 4 The second end of [component] is connected to the first end of switch S 10 The first end of [component], said switch S 10 The second end of [component] is grounded.

[0028] In one embodiment, the first sub-switching circuit includes a switch S 1A , the second sub-switching circuit includes a switch S 2A , the third sub-switching circuit includes a switch S 3A , the fourth sub-switching circuit includes a switch S 4A , the fifth sub-switching circuit includes a switch S 1B , the sixth sub-switching circuit includes a switch S 2B , the seventh sub-switching circuit includes a switch S 3B , the eighth sub-switching circuit includes a switch S 4B ;

[0029] The first end of the switch S 1A is connected to the second end of the switch S 1 , and the second end of the switch S 1A is connected to the first end of the switch S 2 ; The first end of the switch S 2A is connected to the second end of the switch S 1 , and the second end of the switch S 2A is connected to the first end of the switch S 4 ; The first end of the switch S 3A is connected to the second end of the switch S 1 , and the second end of the switch S 3A is connected to the first end of the switch S 7 ; The first end of the switch S 4A is connected to the second end of the switch S 1 , and the second end of the switch S 4A is connected to the first end of the switch S 9 ; The first end of the switch S 1B is connected to the first end of the switch S 6 , and the second end of the switch S 1B is connected to the first end of the switch S 2 ; The first end of the switch S 2B is connected to the first end of the switch S 6 , and the second end of the switch S 2B is connected to the first end of the switch S 4 ; The first end of the switch S 3B is connected to the first end of the switch S 6 , and the second end of the switch S 3B is connected to the first end of the switch S 7 ; The first end of the switch S 4B is connected to the first end of the switch S 6 , and the second end of the switch S 4B is connected to the first end of the switch S 9 .

[0030] According to a second aspect, in one embodiment, a DC conversion device is provided, including:

[0031] a DC conversion circuit, which adopts the DC conversion circuit described in any one of the above embodiments;

[0032] a control module, configured to output a first control signal and a second control signal to control the operation of the DC conversion circuit.

[0033] In one embodiment, the control module further includes a startup module and a real-time calibration module for a shared flying capacitor. The startup module is used to charge the shared flying capacitor in the DC conversion circuit until the voltage of the shared flying capacitor in the DC conversion circuit is half of the input voltage before the DC conversion circuit operates; the real-time calibration module for the shared flying capacitor is used to adjust the duty cycle of charging and discharging the shared flying capacitor in the DC conversion circuit during the operation of the DC conversion circuit to perform real-time calibration on the shared flying capacitor in the DC conversion circuit, ensuring that the voltage of the shared flying capacitor in the DC conversion circuit is half of the input voltage.

[0034] In one embodiment, the startup module includes a first comparator, a second comparator, a first latch, a second latch, resistor R 21 , resistor R 22 , capacitor C 21 , resistor R 23 , resistor R 24 , capacitor C 22 , resistor R 25 , resistor R 26 , capacitor C 23 , resistor R 27 , resistor R 28 and capacitor C 24 ;

[0035] The first end of the resistor R 21 is used to obtain a reference voltage. The second end of the resistor R 21 is connected to the non-inverting input terminal of the first comparator. The second end of the resistor R 21 is also connected to the first end of the resistor R 22 . The second end of the resistor R 22 is grounded. The second end of the resistor R 21 is also connected to the first end of the capacitor C 21 . The second end of the capacitor C 21 is grounded;

[0036] The first end of the resistor R 23 is used to obtain the node voltage of the end of the shared flying capacitor for connecting the input voltage. The resistor R23 The second end is connected to the inverting input terminal of the first comparator, and the resistor R 23 The second end is also connected to the resistor R 24 The first end, and the resistor R 24 The second end is grounded, and the resistor R 23 The second end is also connected to the capacitor C 22 The first end, and the capacitor C 22 The second end is grounded;

[0037] The output terminal of the first comparator is connected to the reset terminal of the first latch. The set terminal of the first comparator is used to obtain the enable signal of the startup module, and the output terminal of the first latch is used to output the charging signal of the shared flying capacitor;

[0038] The resistor R 25 The first end is used to obtain the reference voltage. The resistor R 25 The second end is connected to the non-inverting input terminal of the second comparator. The resistor R 25 The second end is also connected to the resistor R 26 The first end, and the resistor R 26 The second end is grounded. The resistor R 25 The second end is also connected to the capacitor C 23 The first end, and the capacitor C 23 The second end is grounded;

[0039] The resistor R 27 The first end is used to obtain the input voltage. The resistor R 27 The second end is connected to the inverting input terminal of the second comparator. The resistor R 27 The second end is also connected to the resistor R 28 The first end, and the resistor R 28 The second end is grounded. The resistor R 27 The second end is also connected to the capacitor C 24 The first end, and the capacitor C 24 The second end is grounded;

[0040] The output terminal of the second comparator is connected to the reset terminal of the second latch. The set terminal of the second comparator is used to obtain the enable signal of the startup module, and the output terminal of the second latch is used to output the enable signal of the DC conversion circuit.

[0041] In one embodiment, the real-time calibration module of the shared flying capacitor includes a differential difference amplifier, a third comparator, a resistor R 31 a resistor R 32 a capacitor C 31 a resistor R 33 a resistor R 34 a capacitor C32 , resistor R 35 , resistor R 36 , capacitor C 33 , resistor R 37 and capacitor C 34 ;

[0042] The first end of the resistor R 31 is used to obtain the node voltage of the end of the shared flying capacitor for connecting the input voltage. The second end of the resistor R 31 is connected to the first non-inverting input terminal of the differential difference amplifier. The second end of the resistor R 31 is also connected to the first end of the resistor R 32 . The second end of the resistor R 32 is grounded. The second end of the resistor R 31 is also connected to the first end of the capacitor C 31 . The second end of the capacitor C 31 is grounded;

[0043] The first end of the resistor R 33 is used to obtain the node voltage of the end where the current in the shared flying capacitor returns to the ground. The second end of the resistor R 33 is connected to the first inverting input terminal of the differential difference amplifier. The second end of the resistor R 33 is also connected to the first end of the resistor R 34 . The second end of the resistor R 34 is grounded. The second end of the resistor R 33 is also connected to the first end of the capacitor C 32 . The second end of the capacitor C 32 is grounded;

[0044] The first end of the resistor R 35 is used to obtain the input voltage. The second end of the resistor R 35 is connected to the second non-inverting input terminal of the differential difference amplifier. The second end of the resistor R 35 is also connected to the first end of the resistor R 36 . The second end of the resistor R 36 is grounded. The second end of the resistor R 35 is also connected to the first end of the capacitor C 33 . The second end of the capacitor C 33 is grounded;

[0045] The first end of the resistor R 37 is used to be grounded. The second end of the resistor R 37 is connected to the second inverting input terminal of the differential difference amplifier. The second end of the resistor R 37 is also connected to the first end of the capacitor C 34 . The second end of the capacitor C34 The second end is grounded;

[0046] The output terminal of the differential difference amplifier is connected to the inverting input terminal of the third comparator. The non-inverting input terminal of the third comparator is used to obtain a ramp signal, and the output terminal of the third comparator is used to adjust the duty cycle of charging and discharging the shared flying capacitor in the DC conversion circuit.

[0047] According to the DC conversion circuit and the DC conversion device of the above embodiment, the DC conversion circuit includes a shared flying capacitor module, a buck conversion module, and a circuit switching module. The shared flying capacitor module includes a first power switch group and a shared flying capacitor. The first power switch group responds to a first control signal to control the connection of the shared flying capacitor to the input voltage or control the current of the shared flying capacitor to flow back to the ground. Each buck conversion circuit in the buck conversion module includes a second power switch group, a flying capacitor, and a power inductor. The second power switch group is turned on and off in response to a second control signal to realize the charging or discharging of the flying capacitor and the magnetization or demagnetization of the power inductor. The circuit switching module is connected between the buck conversion module and the shared flying capacitor module. The circuit switching module responds to the first control signal to connect the shared flying capacitor module to a set buck conversion circuit in the buck conversion module, which is used to charge or discharge the shared flying capacitor while supplying power to the load. While having a smaller average inductor current and a wider duty cycle range, the present application further reduces the voltage stress of the switch by using one shared flying capacitor and four independent flying capacitors, enabling the use of low-voltage power transistors with better performance for the implementation of the DC conversion circuit. In addition, the DC conversion circuit has no cross-regulation during load transients and does not require additional components for multi-output applications or to create additional power paths. Description of the Drawings

[0048] Figure 1 It is a power supply schematic diagram of the processing system in the background art;

[0049] Figure 2 It is a schematic structural diagram of the DC conversion circuit in an embodiment;

[0050] Figure 3 It is a circuit schematic diagram of the DC conversion circuit in an embodiment;

[0051] Figure 4 It is a circuit schematic diagram of the DC conversion circuit in the 1B phase in an embodiment;

[0052] Figure 5 It is a circuit schematic diagram of the DC conversion circuit in the 1A phase in an embodiment;

[0053] Figure 6 It is a circuit schematic diagram of the DC conversion circuit in the 2B phase in an embodiment;

[0054] Figure 7 Schematic diagram of the DC conversion circuit in the 2A phase in one embodiment;

[0055] Figure 8 Schematic diagram of the structure of the DC conversion device in another embodiment;

[0056] Figure 9 Schematic diagram of the structure of the control module in one embodiment;

[0057] Figure 10 Schematic diagram of the circuit of the startup module in one embodiment;

[0058] Figure 11 Schematic diagram of the circuit of the real-time calibration module sharing flying capacitors in one embodiment;

[0059] Figure 12 Schematic diagram of the circuit of the DC conversion device in one embodiment;

[0060] Figure 13 Working waveform diagram of the DC conversion device in the 1A phase and 1B phase in one embodiment. Specific implementation manners

[0061] The present invention will be further described in detail below in conjunction with the accompanying drawings through specific implementation manners. Similar elements in different implementation manners adopt related similar element numbers. In the following implementation manners, many detailed descriptions are provided to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification to avoid drowning the core part of the present application with excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the descriptions in the specification and the general technical knowledge in the art.

[0062] In addition, the features, operations, or characteristics described in the specification can be combined in any appropriate manner to form various implementation manners. At the same time, the steps or actions in the method description can also be reordered or adjusted in an obvious manner by those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for clearly describing a certain embodiment and do not mean a necessary sequence unless it is stated that a certain sequence must be followed.

[0063] The serial numbers assigned to components in this text itself, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. And as used in this application, "connection" and "coupling", unless otherwise specified, both include direct and indirect connection (coupling).

[0064] This application provides a DC conversion circuit and its corresponding DC conversion device, which can achieve a high voltage conversion ratio with multiple outputs, and at the same time can achieve a high power conversion rate, without an output cross-regulation effect, reduce the voltage stress of power transistors, so as to use high-performance low-voltage transistors, and without adding any additional components. The following is a specific elaboration.

[0065] Please refer to Figure 2 , a DC conversion circuit 110 provided in an embodiment includes a shared flying capacitor module 111, a buck conversion module 112, and a circuit switching module 113.

[0066] In an embodiment, the shared flying capacitor module 111 includes a first power switch group 1111 and a shared flying capacitor 1112. The first power switch group 1111 responds to a first control signal to control the connection of the shared flying capacitor 1112 to the input voltage or control the current of the shared flying capacitor 1112 to flow back to ground.

[0067] In an embodiment, the buck conversion module 112 includes at least two buck conversion circuits 1121 operating in parallel. Each buck conversion circuit 1121 includes a second power switch group 11211, a flying capacitor 11212, and a power inductor 11213. The second power switch group 11211 in each buck conversion circuit 1121 is turned on and off in response to a second control signal to achieve the charging or discharging of the flying capacitor 11212, and the magnetization or demagnetization of the power inductor 11213.

[0068] It should be noted that this application does not limit the number of buck conversion circuits 1121 in the buck conversion module 112. In engineering practice, the number of buck conversion circuits 1121 can be adjusted according to power requirements, voltage conversion ratio, and system optimization strategies.

[0069] In an embodiment, the circuit switching module 113 is connected between the buck conversion module 112 and the shared flying capacitor module 111. The circuit switching module 113 responds to the first control signal to connect the shared flying capacitor module 111 to a set buck conversion circuit 1121 in the buck conversion module 112 for charging or discharging the shared flying capacitor 1112. Among them, the frequency of the second control signal is greater than the frequency of the first control signal.

[0070] In one embodiment, the circuit switching module 113 includes a first switching circuit 1131 and a second switching circuit 1132. The circuit switching module 113 turns on the first switching circuit 1131 in response to a first control signal. In this state, the shared flying capacitor 1112 discharges. Alternatively, the circuit switching module 113 turns on the second switching circuit 1132 in response to the first control signal. In this state, the shared flying capacitor 1112 charges. Among them, the first switching circuit 1131 and the second switching circuit 1132 work alternately to ensure that the capacitance voltage of the shared flying capacitor 1112 does not shift after long-term operation and maintain the steady-state operation of the circuit.

[0071] In one embodiment, the buck conversion module 112 in the DC conversion circuit 110 of the present application includes four buck conversion circuits 1121 operating in parallel, namely a first buck conversion circuit 1121a, a second buck conversion circuit 1121b, a third buck conversion circuit 1121c, and a fourth buck conversion circuit 1121d.

[0072] In one embodiment, corresponding to the four buck conversion circuits 1121 operating in parallel, the first switching circuit 1131 includes a first sub-switching circuit 11311, a second sub-switching circuit 11312, a third sub-switching circuit 11313, and a fourth sub-switching circuit 11314, and the second switching circuit 1132 includes a fifth sub-switching circuit 11321, a sixth sub-switching circuit 11322, a seventh sub-switching circuit 11323, and an eighth sub-switching circuit 11324. The first sub-switching circuit 11311 and the fifth sub-switching circuit 11321 are connected to the first buck conversion circuit 1121a, the second sub-switching circuit 11312 and the sixth sub-switching circuit 11322 are connected to the second buck conversion circuit 1121b, the third sub-switching circuit 11313 and the seventh sub-switching circuit 11323 are connected to the third buck conversion circuit 1121c, and the fourth sub-switching circuit 11314 and the eighth sub-switching circuit 11324 are connected to the fourth buck conversion circuit 1121d.

[0073] In one embodiment, the DC conversion circuit 110 provided by the present application includes 18 power transistors S 1 ~S 10 (i.e., the first power switch group 1111 and the second power switch group 11211), S 1A ~S 4A (i.e., the switches in the first switching circuit 1131) and S 1B ~S 4B (i.e., the switches in the second switching circuit 1132), 5 flying capacitors C F0 ~C F4 (i.e., the shared flying capacitor 1112 and the flying capacitors 11212 in each buck conversion circuit 1121), and 4 power inductors L1 ~L 4 (i.e., the power inductor 11213 in each buck conversion circuit 1121). From the switching nodes in each buck conversion circuit 1121 (i.e., Figure 3 V in SW1 ~V SW4 ), the DC conversion circuit 110 of the present application can be regarded as a three-level buck converter connecting four independent 2PHBs, and at the same time multiplexing the first power switch group 1111 (switches S 1 and switch S 6 ) of the three-level buck converter and the shared flying capacitor 1112. The following will be described in detail with a specific circuit.

[0074] It should be noted that the switching nodes in each buck conversion circuit 1121 correspond to a three-level buck converter of an independent 2PHB. Therefore, the DC conversion circuit 110 can be regarded as a structure of 4 parallel 2PHBs. The three-level buck converter cascades two groups of power switches through an intermediate potential, so that the withstand voltage of the power devices in the buck conversion circuit 1121 becomes half of the input voltage. Therefore, low-voltage power devices with better FoM values can be used, thereby reducing switching losses and improving efficiency. At the same time, the DC conversion circuit 110 multiplexes the first power switch group 1111 and the shared flying capacitor 1112 of the three-level buck converter, reducing the need for additional switching devices and optimizing the circuit design.

[0075] Please refer to Figure 3 , in one embodiment, the first power switch group 1111 includes switches S 1 and switch S 6 , and the shared flying capacitor 1112 is the flying capacitor C F0 . The first end of switch S 1 is connected to the input voltage, the second end of switch S 1 is connected to the first end of flying capacitor C F0 , the second end of flying capacitor C F0 is connected to the first end of switch S 6 , and the second end of switch S 6 is grounded.

[0076] In one embodiment, the second power switch group 11211 of the first buck conversion circuit 1121a includes switches S 2 and switch S 3 , the flying capacitor 11212a of the first buck conversion circuit 1121a is the flying capacitor C F1 , and the power inductor 11213a of the first buck conversion circuit 1121a is the inductor L 1 . The second power switch group 11211 of the second buck conversion circuit 1121b includes switches S 4 and switch S 5, the flying capacitor 11212b of the second buck conversion circuit 1121b is the flying capacitor C F2 , the power inductor 11213b of the second buck conversion circuit 1121b is the inductor L 2 . The second power switch group 11211 of the third buck conversion circuit 1121c includes the switch S 7 and the switch S 8 , the flying capacitor 11212c of the third buck conversion circuit 1121c is the flying capacitor C F3 , the power inductor 11213c of the third buck conversion circuit 1121c is the inductor L 3 . The second power switch group 11211 of the fourth buck conversion circuit 1121d includes the switch S 9 and the switch S 10 , the flying capacitor 11212d of the fourth buck conversion circuit 1121d is the flying capacitor C F4 , the power inductor 11213d of the fourth buck conversion circuit 1121d is the inductor L 4 .

[0077] In one embodiment, the first end of the switch S 2 is connected to the first end of the flying capacitor C F1 , the second end of the flying capacitor C F1 is connected to the first end of the switch S 3 , the second end of the switch S 2 is used to output the voltage (i.e., Figure 3 V in O1 ), the second end of the switch S 2 is also connected to the first end of the inductor L 1 , the second end of the inductor L 1 is connected to the first end of the switch S 3 , and the second end of the switch S 3 is grounded. The first end of the switch S 4 is connected to the first end of the flying capacitor C F2 , the second end of the flying capacitor C F2 is connected to the first end of the switch S 5 , the second end of the switch S 4 is used to output the voltage (i.e., Figure 3 V in O2 ), the second end of the switch S 4 is also connected to the first end of the inductor L 2 , the second end of the inductor L 2 is connected to the first end of the switch S 5 , and the second end of the switch S 5 is grounded. The first end of the switch S 7 is connected to the first end of the flying capacitor C F3 , the second end of the flying capacitor C F3 is connected to the switch S8 The first end of, switch S 7 The second end is for outputting voltage (i.e., Figure 3 V in O3 ), switch S 7 The second end is also connected to the first end of inductor L 3 The second end of inductor L 3 is connected to the first end of switch S 8 The first end of, switch S 8 The second end is grounded. Switch S 9 The first end is connected to the first end of flying capacitor C F4 The second end of flying capacitor C F4 is connected to the first end of switch S 10 The first end of, switch S 9 The second end is for outputting voltage (i.e., Figure 3 V in O4 ), switch S 9 The second end is also connected to the first end of inductor L 4 The first end of inductor L 4 is connected to the first end of switch S 10 The first end of, switch S 10 The second end is grounded.

[0078] In an embodiment, the first sub-switching circuit 11311 includes switch S 1A , the second sub-switching circuit 11312 includes switch S 2A , the third sub-switching circuit 11313 includes switch S 3A , the fourth sub-switching circuit 11314 includes switch S 4A , the fifth sub-switching circuit 11321 includes switch S 1B , the sixth sub-switching circuit 11322 includes switch S 2B , the seventh sub-switching circuit 11323 includes switch S 3B , the eighth sub-switching circuit 11324 includes switch S 4B . Switch S 1A The first end is connected to the second end of switch S 1 , switch S 1A The second end is connected to the first end of switch S 2 , switch S 2A The first end is connected to the second end of switch S 1 , switch S 2A The second end is connected to the first end of switch S 4 , switch S 3A The first end is connected to the second end of switch S 1 , switch S 3A The second end is connected to the first end of switch S 7 , switch S 4AThe first end of 1 is connected to the second end of switch S, switch S 4A The second end of 9 is connected to the first end of switch S, switch S 1B The first end of 6 is connected to the first end of switch S, switch S 1B The second end of 2 is connected to the first end of switch S, switch S 2B The first end of 6 is connected to the first end of switch S, switch S 2B The second end of 4 is connected to the first end of switch S, switch S 3B The first end of 6 is connected to the first end of switch S, switch S 3B The second end of 7 is connected to the first end of switch S, switch S 4B The first end of 6 is connected to the first end of switch S, switch S 4B The second end of 9 is connected to the first end of

[0079] In summary, the working mode of the DC conversion circuit 110 provided in this application can be disassembled into two cooperating duty cycle controls, which are respectively used for the charge and discharge control of the flying capacitor C F0 , and the charge and discharge control of each buck conversion circuit 1121. The DC conversion circuit 110 adopts a multi-phase control strategy. Based on the four buck conversion circuits 1121, the entire operating cycle is divided into eight phases to achieve balanced energy transfer. For the flying capacitor C F0 , it is necessary to maintain charge balance during the operation of the DC conversion circuit 110. Therefore, within a complete operating cycle, it will go through two processes: charging (turning on the second switching circuit 1132) and discharging (turning on the first switching circuit 1131).

[0080] A complete operating cycle is divided into 8 phases, including four A phases when the flying capacitor C F0 is in the discharging state (i.e., the first sub-switching circuit 11311, the second sub-switching circuit 11312, the third sub-switching circuit 11313, and the fourth sub-switching circuit 11314), and four B phases when the flying capacitor C F0 is in the charging state (i.e., the fifth sub-switching circuit 11321, the sixth sub-switching circuit 11322, the seventh sub-switching circuit 11323, and the eighth sub-switching circuit 11324). The A phases and B phases appear alternately as 1B-1A-2B-2A-3B-3A-4B-4A, and in the actual circuit, conduction is carried out in the following manner: the fifth sub-switching circuit 11321 (switch S1B ) - The first sub-switching circuit 11311 (switch S 1A ) - The sixth sub-switching circuit 11322 (switch S 2B ) - The second sub-switching circuit 11312 (switch S 2A ) - The seventh sub-switching circuit 11323 (switch S 3B ) - The third sub-switching circuit 11313 (switch S 3A ) - The eighth sub-switching circuit 11324 (switch S 4B ) - The fourth sub-switching circuit 11314 (switch S 4A ), thus forming a complete working cycle.

[0081] Please refer to Figures 4 - 7 , taking the fifth sub-switching circuit 11321 (switch S 1B ) - The first sub-switching circuit 11311 (switch S 1A ) - The sixth sub-switching circuit 11322 (switch S 2B ) - The second sub-switching circuit 11312 (switch S 2A ) as an example. In the 1B phase, switches S 1 , S 4 , S 5 , S 7 to S 10 and S 1B are turned on, and switches S 2 , S 3 , S 6 , S 1A to S 4A and S 2B to S 4B are turned off. At this time, the flying capacitors C F0 and C F1 are charged, the flying capacitors C F2 to C F4 are discharged, the inductor L 1 is magnetized, the inductors L 2 to L 4 are demagnetized, and other outputs are in the discharge stage of the 2PHB converter. In the 2B phase, switches S 1 to S 3 , S 7 to S 10 and S 2B are turned on, and switches S 4 , S 5 , S 6 , S 1A to S 4A , S 1B ​3B and switch S 4B is turned off. At this time, the flying capacitor C F0 and the flying capacitor C F2 are charged. The flying capacitor C F1 、the flying capacitor C F3 and the flying capacitor C F4 are discharged, and the inductor L 2 is magnetized. The inductor L 1 、the inductor L 3 and the inductor L 4 is demagnetized, and the other outputs are in the discharge stage of 2PHB. For the 1A phase and the 2A phase, it is basically the same as the 1B phase and the 2B phase, except that the flying capacitor C F0 is in the discharge state in these two phases by turning off S 1 and turning on S 6 is realized.

[0082] In one embodiment, the voltage conversion ratio (VCR) of the DC conversion circuit 110 provided by the present application is D / 2(1 + D). For the DSD converter, its VCR is D / 2, while the VCR of the 2PHB converter is D / (1 + D), where D represents the duty cycle. Therefore, the DC conversion circuit 110 provided by the present application has a wider range of duty cycle values in the application of converting 12V to 1.8V to 0.8V. And for the average value of the inductor current, the I L_AVG of the DSD converter is I LOAD / 2, while the I L_AVG of the DC conversion circuit 110 provided by the present application and the 2PHB is I LOAD / (1 + D). In addition, the voltage on the flying capacitor C F0 on the DC conversion circuit 110 provided by the present application is V IN / 2, while the voltage on other flying capacitors is their corresponding output voltages. For the switches S 2 ~switch S 5 and the switches S 7 ~switch S 10 the voltage stress on them is reduced to V IN / 2 - V OUT , where, I L_AVG represents the average value of the inductor current, I LOAD represents the load current, V IN represents the input voltage, and V OUT represents the output voltage.

[0083] In summary, the DC conversion circuit 110 provided by the present application inherits the advantages of DSD and 2PHB, has a small average inductor current and a wider duty cycle range. At the same time, by using a shared flying capacitor 1112 and four independent flying capacitors 11212, the voltage stress of the switch is further reduced, enabling the implementation of the DC conversion circuit 110 to use more low-voltage power transistors with better performance. In addition, the DC conversion circuit 110 has no cross-regulation during load transients and does not require additional components for multi-output applications or creating additional power paths.

[0084] Please refer to Figure 8 , another embodiment further provides a DC conversion device 100, including a DC conversion circuit 110 and a control module 120. The DC conversion circuit 110 adopts the DC conversion circuit 110 in any of the above embodiments. Since the DC conversion circuit 110 has been clearly described in the above circuit, it will not be elaborated here. The control module 120 is configured to output a first control signal and a second control signal to control the operation of the DC conversion circuit 110.

[0085] Please refer to Figure 9 , in one embodiment, the control module 120 further includes a startup module 121 and a real-time calibration module 122 for the shared flying capacitor. The startup module 121 is configured to charge the flying capacitor C in the DC conversion circuit 110 before the DC conversion circuit 110 operates until the voltage of the flying capacitor C in the DC conversion circuit 110 is half of the input voltage. The real-time calibration module 122 for the shared flying capacitor is configured to adjust the charging and discharging duty cycle of the flying capacitor C in the DC conversion circuit 110 during the operation of the DC conversion circuit 110 to ensure that the voltage of the flying capacitor C in the DC conversion circuit 110 is half of the input voltage. F0 in the DC conversion circuit 110 until the voltage of the flying capacitor C in the DC conversion circuit 110 F0 is half of the input voltage. The real-time calibration module 122 for the shared flying capacitor is configured to adjust the charging and discharging duty cycle of the flying capacitor C in the DC conversion circuit 110 during the operation of the DC conversion circuit 110 to ensure that the voltage of the flying capacitor C in the DC conversion circuit 110 F0 is half of the input voltage. F0 is half of the input voltage.

[0086] Please refer to Figure 10 , in one embodiment, the startup module 121 includes a first comparator 1211, a second comparator 1212, a first latch 1213, a second latch 1214, a resistor R 21 , a resistor R 22 , a capacitor C 21 , a resistor R 23 , a resistor R 24 , a capacitor C 22 , a resistor R 25 , a resistor R 26 , a capacitor C 23 , a resistor R 27 , a resistor R 28 and a capacitor C 24 . The resistor R21 The first end of is used to obtain a reference voltage (i.e., Figure 10 VDD in 21 The second end of resistor R is connected to the non-inverting input terminal of the first comparator 1211. Resistor R 21 The second end is also connected to the first end of resistor R 22 The second end of resistor R 22 The second end is grounded. Resistor R 21 The second end is also connected to the first end of capacitor C 21 The first end of capacitor C 21 The second end is grounded. Resistor R 23 The first end is used to obtain the node voltage of the flying capacitor C F0 at the end connected to the input voltage (i.e., Figure 10 V in A , that is, Figure 3 the voltage at point A in 23 The second end of resistor R is connected to the inverting input terminal of the first comparator 1211. Resistor R 23 The second end is also connected to the first end of resistor R 24 The second end of the resistor R 24 The second end is grounded. Resistor R 23 The second end is also connected to the first end of capacitor C 22 The first end of capacitor C 22 The second end is grounded. The output terminal of the first comparator 1211 is connected to the reset terminal of the first latch 1213. The set terminal of the first comparator 1211 is used to obtain the enable signal of the start module 121 (i.e., Figure 10 EN in SU ), and the output terminal of the first latch 1213 is used to output the charging signal of the flying capacitor C F0 (i.e., Figure 10 PCS in 25 The first end of resistor R is used to obtain a reference voltage (i.e., Figure 10 VDD in 25 The second end of resistor R is connected to the non-inverting input terminal of the second comparator 1212. Resistor R 25 The second end is also connected to the first end of resistor R 26 The second end of resistor R 26 The second end is grounded. Resistor R 25 The second end is also connected to the first end of capacitor C 23 The first end of capacitor C 23 The second end is grounded. Resistor R 27 The first end is used to obtain the input voltage (i.e., Figure 10 V in IN ), resistor R 27 The second end is connected to the inverting input terminal of the second comparator 1212. Resistor R 27The second terminal of 28 is also connected to the first terminal of resistor R 28 . The second terminal of resistor R 27 is grounded. The second terminal of 24 is also connected to the first terminal of capacitor C 24 . The second terminal of capacitor C Figure 10 is grounded. The output terminal of the second comparator 1212 is connected to the reset terminal of the second latch 1214. The set terminal of the second comparator 1212 is used to obtain the enable signal of the startup module 121 (i.e., SU EN in Figure 10 ), and the output terminal of the second latch 1214 is used to output the enable signal of the DC conversion circuit 110 (i.e., C EN in

[0087] ). Among them, the first latch 1213 and the second latch 1214 adopt SR latches. The ratio of the resistance values of resistor R 21 and resistor R 22 is 4:1. The ratio of the resistance values of resistor R 23 and resistor R 24 is 5:1. The ratio of the resistance values of resistor R 25 and resistor R 26 is 4:1. The ratio of the resistance values of resistor R 27 and resistor R 28 is 11:1. After determining the ratio of the resistance values of each resistor, the node voltage on the node can be sampled using resistor voltage division.

[0088] It should be noted that in order to ensure the normal operation of the DC conversion device 100 and prevent the switch S 6 from malfunctioning during the startup of the DC conversion device 100. Therefore, a startup module 121 is required to pre-charge the flying capacitor C F0 to V IN / 2 before starting the DC conversion device 100. When EN SU is at a low level and V IN starts to rise from 0V, the switches S 1 and S 6 conduct, and the flying capacitor C F0 starts to be pre-charged. When the voltage V CF0 of the flying capacitor reaches 6V, the pre-charging ends, and the switches S 1 and S 6 turn off. When V IN reaches 12V, the normal control loop of the DC conversion device 100 starts.

[0089] Please refer to Figure 11, in one embodiment, the real-time calibration module 122 for sharing flying capacitors includes a differential difference amplifier 1221, a third comparator 1222, a resistor R 31 , a resistor R 32 , a capacitor C 31 , a resistor R 33 , a resistor R 34 , a capacitor C 32 , a resistor R 35 , a resistor R 36 , a capacitor C 33 , a resistor R 37 and a capacitor C 34 . The first end of the resistor R 31 is used to obtain the node voltage of the end of the flying capacitor C F0 for connecting the input voltage (i.e., V Figure 11 in A , that is, the voltage at point A in Figure 11 ). The second end of the resistor R 31 is connected to the first non-inverting input terminal of the differential difference amplifier 1221. The second end of the resistor R 31 is also connected to the first end of the resistor R 32 . The second end of the resistor R 32 is grounded. The second end of the resistor R 31 is also connected to the first end of the capacitor C 31 . The second end of the capacitor C 31 is grounded. The first end of the resistor R 33 is used to obtain the node voltage of the end where the current in the flying capacitor C F0 flows back to the ground (i.e., V Figure 11 in B , that is, the voltage at point B in Figure 11 ). The second end of the resistor R 33 is connected to the first inverting input terminal of the differential difference amplifier 1221. The second end of the resistor R 33 is also connected to the first end of the resistor R 34 . The second end of the resistor R 34 is grounded. The second end of the resistor R 33 is also connected to the first end of the capacitor C 32 . The second end of the capacitor C 32 is grounded. The first end of the resistor R 35 is used to obtain the input voltage. The second end of the resistor R 35 is connected to the second non-inverting input terminal of the differential difference amplifier 1221. The second end of the resistor R 35 is also connected to the first end of the resistor R 36 . The second end of the resistor R 36 is grounded. The second end of the resistor R 35 is also connected to the first end of the capacitor C 33 . The second end of the capacitor C33 The second terminal of which is grounded. Resistor R 37 The first terminal of which is used for grounding. Resistor R 37 The second terminal of which is connected to the second inverting input terminal of the differential difference amplifier 1221. Resistor R 37 The second terminal of which is also connected to the first terminal of capacitor C 34 Capacitor C 34 The second terminal of which is grounded. The output terminal of the differential difference amplifier 1221 is connected to the inverting input terminal of the third comparator 1222. The non-inverting input terminal of the third comparator 1222 is used to obtain a ramp signal. The output terminal of the third comparator 1222 is used to adjust the duty cycle of the charging and discharging of the flying capacitor C F0 in (that is, Figure 11 ABsel in).

[0090] Among them, the ratio of the resistance values of resistor R 31 and resistor R 32 is 11:1. The ratio of the resistance values of resistor R 33 and resistor R 34 is 11:1. The ratio of the resistance values of resistor R 35 and resistor R 36 is 23:1.

[0091] It should be noted that in the DC conversion device 100 proposed in this application, like the three-level buck converter, the voltage V F0 of the flying capacitor C CF0 should always be V IN / 2; however, many imperfect conditions such as parasitic capacitance and time mismatch between drive signals will affect it. In order to calibrate the voltage V F0 of the flying capacitor C CF0 , it is necessary to sense the voltages of the two terminals V Figure 11 of the flying capacitor C F0 through the differential difference amplifier 1221 (DDA) shown in A and V B and compare them with V IN / 2. In the negative feedback loop, the two input pairs of the DDA follow the following formula:

[0092] V PP -V PN =V NP -V NN

[0093] Among them, V PP represents the voltage of the first non-inverting input terminal, V PN represents the voltage of the first inverting input terminal, V NP represents the voltage of the second non-inverting input terminal, V NNRepresents the voltage of the second inverting input terminal.

[0094] Therefore, the flying capacitor C F0 The voltage V on CF0 = V A - V B Is modulated at V IN / 2. The voltage V output from the output terminal of the differential difference amplifier 1221 CAIL Is compared with the 1 MHz ramp signal RAMP CAIL To generate the charging and discharging duty cycles of the flying capacitor C F0 When V CF0 Is lower than V IN / 2, V CAIL Will increase, causing the charging duty cycle to increase. Similarly, when V CF0 Is higher than V IN / 2, V CAIL Will decrease, causing the discharging duty cycle to increase.

[0095] Meanwhile, in the DC conversion circuit 110, the operating frequency of the system is 1 MHz, while the frequency of the pulse width modulation (PWM) ramp signal of each phase in the four A phases and four B phases is 2 MHz. That is, PWM controls the second power switch group 11211 in each buck conversion circuit 1121, and the switching frequency is 2 MHz. The first power switch group 1111 is controlled by the signal ABsel that is calibrated in real time by the shared flying capacitor 1112, and the switching frequency is 1 MHz. The switches in each sub-switching circuit are obtained by the logical AND of PWM and ABsel, and the switching frequency is also 1 MHz.

[0096] Please refer to Figure 12 , in one embodiment, the control module 120 further includes a voltage mode control module 123. The voltage mode control module 123 relies on the feedback of the output voltage to adjust the PWM duty cycle to maintain the stability of the output voltage. In the voltage mode control module 123, there is a type III compensated PWM controller 1231, a resistor R 41 , a resistor R 42 And an error amplifier 1232 for each output terminal. The first end of a resistor R 41 Connected to each output terminal of the DC conversion circuit 110, the second end of the resistor R 41 Is connected to the first end of the resistor R 42 , the second end of the resistor R 42 Is grounded, and the second end of the resistor R 42The first end is also connected to the inverting input terminal of the type-III compensated PWM controller 1231. The non-inverting input terminal of the type-III compensated PWM controller 1231 is connected to a reference voltage. The output terminal of the type-III compensated PWM controller 1231 is connected to the inverting input terminal of the error amplifier 1232, and the non-inverting input terminal of the error amplifier 1232 obtains a ramp signal.

[0097] It should be noted that the type-III compensated PWM controller 1231 eliminates the double poles generated by the power inductor and the load capacitor during the voltage mode control process by introducing two zeros. After compensation, the unity gain frequency of the DC conversion device 100 reaches 160 kHz, and the phase margin is 71°. Please refer to Figure 13 , which shows the working waveforms of Phase 1A and Phase 1B. The output V of the type-III compensated PWM controller 1231 EA1 is compared with the ramp signal RAMP1. The frequency f of RAMP1 s is 2 MHz. Therefore, the gate drive signal V S2 and V S3 are generated with the help of the PWM signal and some logic circuits and drive circuits. The charge and discharge duty cycle of the flying capacitor C F0 is generated by the real-time calibration circuit of the flying capacitor C F0 voltage, and the drive signals V 1B and V 1A are generated by the logic circuit and the drive circuit. Among them, V S2 represents the voltage of the switch S 2 , and V S3 represents the voltage of the switch S 3 .

[0098] In one embodiment, the control module 120 further includes a logic control - non-overlap control - gate drive module 124. The logic control - non-overlap control - gate drive module 124 is connected to the output terminal of the error amplifier 1232. At the same time, the logic control - non-overlap control - gate drive module 124 is also connected to the real-time calibration module 122 of the shared flying capacitor. The logic control - non-overlap control - gate drive module 124 is used to output the switches S 1 ~switch S 10 , switch S 1A ~switch S 4A , switch S 1B ~switch S 4B and the control signals for adjusting the charge and discharge duty cycle of the flying capacitor C F0 in the DC conversion circuit 110.

[0099] In one embodiment, the control module 120 further includes a ramp signal - clock signal generator 125, which is used to generate a ramp signal (RAMP) and a clock signal (CLK) required for PWM (pulse width modulation) control to ensure that each switch performs switching operations in the correct time sequence.

[0100] Those skilled in the art can understand that all or part of the functions of the above - mentioned methods can be implemented in a hardware manner or in a computer - program manner. When all or part of the functions in the above - mentioned embodiments are implemented in a computer - program manner, the program can be stored in a computer - readable storage medium. The storage medium may include: read - only memory, random - access memory, magnetic disk, optical disk, hard disk, etc. The above - mentioned functions are realized by a computer executing this program. For example, the program is stored in the memory of a device. When the processor executes the program in the memory, the above - mentioned all or part of the functions can be realized. In addition, when all or part of the functions in the above - mentioned embodiments are implemented in a computer - program manner, the program can also be stored in a storage medium such as a server, another computer, magnetic disk, optical disk, flash drive or mobile hard disk. It is saved to the memory of the local device by downloading or copying, or the system of the local device is updated. When the processor executes the program in the memory, the above - mentioned all or part of the functions in the above - mentioned embodiments can be realized.

[0101] The above uses specific examples to elaborate on the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art of the present invention, based on the idea of the present invention, several simple deductions, deformations or substitutions can also be made.

Claims

1. A DC conversion circuit, characterized in that: It includes a shared flying capacitor module, a buck conversion module and a circuit switching module; The shared flying capacitor module includes a first power switch group and a shared flying capacitor, wherein the first power switch group controls the shared flying capacitor to be connected to an input voltage or controls the current of the shared flying capacitor to flow back to the ground in response to a first control signal; The buck conversion module includes at least two buck conversion circuits working in parallel, each of which includes a second power switch group, a flying capacitor and a power inductor; the second power switch group is switched on and off in response to a second control signal to realize charging or discharging of the flying capacitor and magnetizing or demagnetizing of the power inductor; The circuit switching module is connected to the buck conversion module and the shared flying capacitor module. The circuit switching module connects the shared flying capacitor module with the buck conversion circuit set in the buck conversion module in response to a first control signal, so as to charge or discharge the shared flying capacitor; Wherein, the frequency of the second control signal is greater than the frequency of the first control signal.

2. The DC conversion circuit according to claim 1, characterized in that: The first power switch group includes a switch S1 and a switch S6, and the shared flying capacitor is a flying capacitor C F0 The first end of the switch S1 is connected to the input voltage, and the second end of the switch S1 is connected to the flying capacitor C F0 The first end of the flying capacitor C F0 The second end of is connected to the first end of the switch S6, and the second end of the switch S6 is grounded.

3. The DC conversion circuit according to claim 2, characterized in that: The circuit switching module includes a first switching circuit and a second switching circuit; The circuit switching module switches on the first switching circuit in response to the first control signal, and the shared flying capacitor is discharged; or, The circuit switching module switches on the second switching circuit in response to the first control signal, and the shared flying capacitor is charged; Wherein, the first switching circuit and the second switching circuit work alternately.

4. The DC conversion circuit according to claim 3, characterized in that: The buck conversion module includes four buck conversion circuits working in parallel: a first buck conversion circuit, a second buck conversion circuit, a third buck conversion circuit and a fourth buck conversion circuit; The first switching circuit includes a first sub-switching circuit, a second sub-switching circuit, a third sub-switching circuit and a fourth sub-switching circuit; The second switching circuit includes a fifth sub-switching circuit, a sixth sub-switching circuit, a seventh sub-switching circuit and an eighth sub-switching circuit; The first sub-switching circuit and the fifth sub-switching circuit are connected to the first step-down conversion circuit; the second sub-switching circuit and the sixth sub-switching circuit are connected to the second step-down conversion circuit; the third sub-switching circuit and the seventh sub-switching circuit are connected to the third step-down conversion circuit; the fourth sub-switching circuit and the eighth sub-switching circuit are connected to the fourth step-down conversion circuit.

5. The DC conversion circuit according to claim 4, characterized in that: The second power switch group of the first buck conversion circuit includes a switch S2 and a switch S3, and the flying capacitor of the first buck conversion circuit is a flying capacitor C F1 , the power inductor of the first buck conversion circuit is inductor L1; The first end of the switch S2 is connected to the flying capacitor C F1 The first end of the flying capacitor C F1 The second end of the switch S2 is connected to the first end of the switch S3, the second end of the switch S2 is used to output voltage, the second end of the switch S2 is also connected to the first end of the inductor L1, the second end of the inductor L1 is connected to the first end of the switch S3, and the second end of the switch S3 is grounded; The second power switch group of the second buck conversion circuit includes a switch S4 and a switch S5, and the flying capacitor of the second buck conversion circuit is a flying capacitor C F2 , the power inductor of the second buck conversion circuit is inductor L2; The first end of the switch S4 is connected to the flying capacitor C F2 The first end of the flying capacitor C F2 The second end of the switch S4 is connected to the first end of the switch S5, the second end of the switch S4 is used to output voltage, the second end of the switch S4 is also connected to the first end of the inductor L2, the second end of the inductor L2 is connected to the first end of the switch S5, and the second end of the switch S5 is grounded; The second power switch group of the third buck conversion circuit includes a switch S7 and a switch S8. The flying capacitor of the third buck conversion circuit is a flying capacitor C F3 , the power inductor of the third buck conversion circuit is inductor L3; The first end of the switch S7 is connected to the flying capacitor C F3 The first end of the flying capacitor C F3 The second end of the switch S7 is connected to the first end of the switch S8, the second end of the switch S7 is used to output voltage, the second end of the switch S7 is also connected to the first end of the inductor L3, the second end of the inductor L3 is connected to the first end of the switch S8, and the second end of the switch S8 is grounded; The second power switch group of the fourth step-down conversion circuit includes a switch S9 and a switch S 10 The flying capacitor of the fourth step-down conversion circuit is a flying capacitor C F4 , the power inductor of the fourth buck conversion circuit is inductor L4; The first end of the switch S9 is connected to the flying capacitor C F4 The first end of the flying capacitor C F4 The second end of the switch S 10 The first end of the switch S9 is used for outputting voltage, the second end of the switch S9 is also connected to the first end of the inductor L4, and the second end of the inductor L4 is connected to the switch S 10 The first end of the switch S 10 The second end is grounded.

6. The DC conversion circuit according to claim 5, characterized in that: The first sub-switching circuit includes a switch S 1A The second sub-switching circuit includes a switch S 2A The third sub-switching circuit includes a switch S 3A The fourth sub-switching circuit includes a switch S 4A The fifth sub-switching circuit includes a switch S 1B The sixth sub-switching circuit includes a switch S 2B The seventh sub-switching circuit includes a switch S 3B The eighth sub-switching circuit includes a switch S 4B ; The switch S 1A The first end of the switch S1 is connected to the second end of the switch S 1A The second end of the switch S2 is connected to the first end of the switch S2; 2A The first end of the switch S1 is connected to the second end of the switch S 2A The second end of the switch S4 is connected to the first end of the switch S4; 3A The first end of the switch S1 is connected to the second end of the switch S 3A The second end of the switch S7 is connected to the first end of the switch S7; 4A The first end of the switch S1 is connected to the second end of the switch S 4A The second end of the switch S9 is connected to the first end of the switch S9; 1B The first end of the switch S6 is connected to the first end of the switch S 1B The second end of the switch S2 is connected to the first end of the switch S2; 2B The first end of the switch S6 is connected to the first end of the switch S 2B The second end of the switch S4 is connected to the first end of the switch S4; 3B The first end of the switch S6 is connected to the first end of the switch S 3B The second end of the switch S7 is connected to the first end of the switch S7; 4B The first end of the switch S6 is connected to the first end of the switch S 4B The second end of is connected to the first end of the switch S9.

7. A DC conversion device, characterized in that: include: A DC conversion circuit, wherein the DC conversion circuit adopts the DC conversion circuit according to any one of claims 1 to 6; The control module is used to output a first control signal and a second control signal to control the DC conversion circuit to work.

8. The DC converter device according to claim 7, characterized in that: The control module also includes a startup module and a real-time calibration module for a shared flying capacitor. The startup module is used to charge the shared flying capacitor in the DC conversion circuit before the DC conversion circuit works until the voltage of the shared flying capacitor in the DC conversion circuit is half of the input voltage. The real-time calibration module for the shared flying capacitor is used to adjust the duty cycle of charging and discharging of the shared flying capacitor in the DC conversion circuit when the DC conversion circuit works, so as to perform real-time calibration on the shared flying capacitor in the DC conversion circuit to ensure that the voltage of the shared flying capacitor is half of the input voltage.

9. The DC conversion device according to claim 8, characterized in that: The startup module includes a first comparator, a second comparator, a first latch, a second latch, a resistor R 21 , resistor R 22 , capacitor C 21 , resistor R 23 , resistor R 24 , capacitor C 22 , resistor R 25 , resistor R 26 , capacitor C 23 , resistor R 27 , resistor R 28 and capacitor C 24 ; The resistor R 21 The first end is used to obtain the reference voltage, the resistor R 21 The second end of the resistor R 21 The second end is also connected to the resistor R 22 The first end of the resistor R 22 The second end of the resistor R 21 The second end is also connected to the capacitor C 21 The first end of the capacitor C 21 The second end of is grounded; The resistor R 23 The first end is used to obtain the node voltage of one end of the shared flying capacitor connected to the input voltage, and the resistor R 23 The second end of the resistor R 23 The second end is also connected to the resistor R 24 The first end of the resistor R 24 The second end of the resistor R 23 The second end is also connected to the capacitor C 22 The first end of the capacitor C 22 The second end of is grounded; The output end of the first comparator is connected to the reset end of the first latch, the set end of the first comparator is used to obtain an enable signal of the startup module, and the output end of the first latch is used to output a charging signal of the shared flying capacitor; The resistor R 25 The first end is used to obtain the reference voltage, the resistor R 25 The second end of the resistor R 25 The second end is also connected to the resistor R 26 The first end of the resistor R 26 The second end of the resistor R 25 The second end is also connected to the capacitor C 23 The first end of the capacitor C 23 The second end of is grounded; The resistor R 27 The first end is used to obtain the input voltage, the resistor R 27 The second end of the resistor R 27 The second end is also connected to the resistor R 28 The first end of the resistor R 28 The second end of the resistor R 27 The second end is also connected to the capacitor C 24 The first end of the capacitor C 24 The second end of is grounded; The output end of the second comparator is connected to the reset end of the second latch, the set end of the second comparator is used to obtain the enable signal of the startup module, and the output end of the second latch is used to output the enable signal of the DC conversion circuit.

10. The DC conversion device according to claim 8 or 9, characterized in that: The real-time calibration module of the shared flying capacitor includes a differential amplifier, a third comparator, a resistor R 31 , resistor R 32 , capacitor C 31 , resistor R 33 , resistor R 34 , capacitor C 32 , resistor R 35 , resistor R 36 , capacitor C 33 , resistor R 37 and capacitor C 34 ; The resistor R 31 The first end is used to obtain the node voltage of one end of the shared flying capacitor connected to the input voltage, and the resistor R 31 The second end of the resistor R is connected to the first non-inverting input terminal of the differential amplifier. 31 The second end is also connected to the resistor R 32 The first end of the resistor R 32 The second end of the resistor R 31 The second end is also connected to the capacitor C 31 The first end of the capacitor C 31 The second end of is grounded; The resistor R 33 The first end of the resistor R is used to obtain the node voltage at one end of the shared flying capacitor where the current flows back to the ground. 33 The second end of the resistor R is connected to the first inverting input terminal of the differential amplifier. 33 The second end is also connected to the resistor R 34 The first end of the resistor R 34 The second end of the resistor R 33 The second end is also connected to the capacitor C 32 The first end of the capacitor C 32 The second end of is grounded; The resistor R 35 The first end is used to obtain the input voltage, the resistor R 35 The second end of the resistor R 35 The second end is also connected to the resistor R 36 The first end of the resistor R 36 The second end of the resistor R 35 The second end is also connected to the capacitor C 33 The first end of the capacitor C 33 The second end of is grounded; The resistor R 37 The first end of the resistor R 37 The second end of the resistor R is connected to the second inverting input terminal of the differential amplifier. 37 The second end is also connected to the capacitor C 34 The first end of the capacitor C 34 The second end of is grounded; The output end of the differential difference amplifier is connected to the inverting input end of the third comparator, the non-inverting input end of the third comparator is used to obtain a ramp signal, and the output end of the third comparator is used to adjust the duty cycle of charging and discharging of the shared flying capacitor in the DC conversion circuit.

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