A multi-phase hybrid converter

Abstract

The present application provides a multi-phase hybrid converter. The multi-phase hybrid converter includes a plurality of phase units connected in parallel, each phase unit including a power switch circuit, a flying capacitor, and a control circuit connected in sequence, the power switch circuit including a first power switch tube, a second power switch tube, a third power switch tube, and a fourth power switch tube connected in series in sequence; the upper plate of the flying capacitor is connected to a first switch node connecting the first power switch tube and the second power switch tube, and the lower plate of the flying capacitor is connected to a second switch node connecting the third power switch tube and the fourth power switch tube. The present application can be extended to any phase, and the flying capacitor of each phase unit can achieve automatic balancing in any working mode. Compared with the prior art, the present application reduces the complexity of circuit design, eliminates the limitations on the number of phases and the working range, and improves the working efficiency of the multi-phase hybrid converter.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a multi-phase hybrid converter. Background Art

[0002] With the continuous expansion of applications for lithium-ion batteries, IoT products, and other applications, the demand for power supply is increasing. Buck converters, as a DC / DC circuit topology, are widely used in power supply applications in aerospace, communications, and military weaponry due to their advantages such as low voltage and current stress on switching devices, wide input and output ranges, minimal passive components, high efficiency, and reliability and flexibility.

[0003] Considering that the multi-phase hybrid converter is affected by factors such as switching frequency, parasitic capacitance, gate control signal, etc. in actual operation, the flying capacitor voltage cannot be balanced to the preset voltage, which has a more significant impact on the system performance of the converter.

[0004] Prior art proposes a flying capacitor self-balancing circuit based on cross-connected capacitors. While stabilizing the output voltage, this circuit adjusts the on-time to achieve flying capacitor self-balancing over a high frequency range and a wide input range. However, this circuit design is complex, increasing system area and power consumption. Furthermore, the feedback loop can be easily affected and limited by operating conditions, hindering the normal operation of the converter. Summary of the Invention

[0005] The present application proposes a multi-phase hybrid converter, which can solve the technical problems that the existing multi-phase hybrid converter is easily affected and restricted by working conditions in the process of achieving flying capacitor self-balancing based on cross-connected capacitors, and the circuit design is complex, which is not conducive to the normal operation of the converter.

[0006] The multi-phase hybrid converter proposed in the embodiment of the present application includes:

[0007] An input terminal, for receiving an input voltage;

[0008] an output terminal connected to a load, for providing an output voltage to the load according to the input voltage;

[0009] A phase output module includes a plurality of parallel phase units, configured to generate control signals based on the output voltage and input voltage to output output currents of multiple phases; each phase unit includes a power switch circuit, a flying capacitor, and a control circuit connected in sequence; the control circuit is configured to generate non-overlapping control signals based on the input voltage, the output voltage, and a preset reference voltage to control the on or off state of the power switch circuit to adjust the output voltage;

[0010] Among them, the power switch circuit includes a first power switch tube, a second power switch tube, a third power switch tube, and a fourth power switch tube connected in series in sequence; the upper plate of the flying capacitor is connected to a first switching node where the first power switch tube and the second power switch tube are connected, and the lower plate of the flying capacitor is connected to a second switching node where the third power switch tube and the fourth power switch tube are connected;

[0011] An output circuit, including a plurality of output inductors and output capacitors; the output inductors correspond to the phase units one by one, the first end of the output inductor is connected to the second switching node in the corresponding phase unit, and the second ends of the output inductors are commonly connected to form an inductor connection node; the first end of the output capacitor is connected to the inductor connection node for providing an output voltage, and the second end of the output capacitor is grounded.

[0012] ]>In some embodiments, when the duty cycle D of the multi-phase hybrid converter is less than 0.25 or 0.25 < D < 0.5, each phase unit can achieve automatic balance through its own flying capacitor.

[0013] In some embodiments, the control circuit includes a non-operating flying capacitor charging control circuit;

[0014] [[ID=]]The non-operating flying capacitor charging control circuit is used to generate a charging control signal according to an external charging enable signal, and when the preset charging condition is satisfied, control the power switch circuit in the non-operating phase unit to conduct, so that the flying capacitor in the non-operating phase unit is connected in parallel with the flying capacitor in the operating phase unit, so as to realize charging the flying capacitor in the non-operating phase unit through the flying capacitor in the operating phase unit.

[0015] In some embodiments, when there are multiple non-operating phase units, the flying capacitor in the same operating phase unit is selected to charge the flying capacitors in the multiple non-operating phase units;

[0016] Or, the flying capacitors in different operating phase units are selected to charge the flying capacitors in the multiple non-operating phase units respectively.

[0017] In some embodiments, the multi-phase hybrid converter includes a charging control signal generation circuit;

[0018] The input end of the charging control signal generation circuit is used to receive a control signal for controlling the operating phase unit, perform frequency division and delay processing on the control signal, and obtain a charging control signal that meets the preset charging condition.

[0019] In some embodiments, when selecting the flying capacitors in different working phase units to charge the flying capacitors in the plurality of non-working phase units respectively, the power replenishment control signal generating circuit includes a plurality of power replenishment control signal generating units;

[0020] Each of the power compensation control signal generating units corresponds one-to-one to the selected working phase unit.

[0021] In some embodiments, the power replenishment control signal generating circuit includes a frequency divider and a pulse generator connected in sequence;

[0022] The frequency divider includes N D flip-flops cascaded in sequence; the pulse generator includes a delay, an inverter and an AND logic gate; N is a positive integer;

[0023] Among them, the input end of the first-level D-type flip-flop is used to receive a non-overlapping control signal for controlling the operation of the selected working phase unit, the input end of the delay device is connected to the output end of the D-type flip-flop of the Nth level; the input end of the inverter is connected to the output end of the delay device; the first input end of the AND logic gate is connected to the output end of the N-level D-type flip-flop, the second input end is connected to the output end of the inverter, and the output end is used to output a power replenishment control signal.

[0024] In some embodiments, the control circuit includes a current detection circuit, a synchronous hysteresis controller, a dead zone control circuit, and a flying capacitor power-up control circuit;

[0025] The current detection circuit is connected to the second switch node and the output capacitor respectively; the current sampling circuit is used to obtain the peak limit value and the valley limit value of the output inductor according to the voltage at the second switch node and the output voltage;

[0026] The synchronous hysteresis controller is connected to the current detection circuit and the output capacitor respectively; the synchronous hysteresis controller is used to generate a drive control signal under the control of an external clock according to the output voltage, a preset reference voltage, and a peak limit or a valley limit;

[0027] The dead zone control circuit is connected to the synchronous hysteresis controller; the dead zone control circuit is used to interleave the drive control signal to generate a non-overlapping control signal to control the on or off of the power switch circuit;

[0028] The flying capacitor power-on control circuit is used to generate a flying capacitor power-on control signal in response to an external instruction before the multi-phase hybrid converter operates, so as to pre-charge the flying capacitor.

[0029] In some embodiments, the control circuit further comprises a channel selection control circuit;

[0030] The channel selection circuit is connected to the non-working flying capacitor power replenishment control circuit, the dead zone control circuit and the flying capacitor power-on control circuit respectively; the selection control circuit is used to selectively activate the flying capacitor in the corresponding non-working phase unit for power replenishment according to the power replenishment control signal; and is used to selectively activate the power switch tube in the corresponding power switch circuit to turn on or off according to the non-overlapping control signal; and, according to the flying capacitor power-on control signal, selectively activate the flying capacitor in the corresponding phase unit for pre-charging.

[0031] In some embodiments, the phase unit further includes a compensation circuit;

[0032] The first input terminal of the compensation circuit is used to receive the output voltage output by the output circuit, the second input terminal is used to receive a preset reference voltage, and the output terminal of the compensation circuit is used to output an error amplified signal;

[0033] The compensation circuit includes a resistor R1, an error amplifier EA, a capacitor C1, a resistor R2 and a capacitor C2;

[0034] The first end of the resistor R1 is connected to the first end of the compensation circuit;

[0035] The non-inverting input terminal of the error amplifier EA is connected to the second terminal of the compensation circuit, the inverting input terminal of the error amplifier EA is connected to the second terminal of the resistor R1, and the output terminal of the error amplifier EA is connected to the output terminal of the compensation circuit;

[0036] The capacitor C1 and the resistor R2 are connected in series, a first end of the capacitor C1 is connected to the inverting input end of the error amplifier EA, and a second end of the resistor R2 is connected to the output end of the error amplifier EA;

[0037] A first end of the capacitor C2 is connected to a first end of the capacitor C1 , and a second end of the capacitor C2 is connected to a second end of the resistor R2 .

[0038] The embodiment of the present application provides a multi-phase hybrid converter, which includes parallel phase units, each phase unit includes a power switch circuit, a flying capacitor and a control circuit connected in sequence, by splitting the two high-voltage power switch tubes in the cross-connected capacitor buck converter in the prior art into two low-voltage power switch tubes and connecting them to a DC node, and the flying capacitor is connected across the connection node of the upper and lower groups of power switch tubes to obtain a phase unit with two completely symmetrical sub-converters, and then the phase units are simultaneously connected in parallel at the DC node to expand the multi-phase hybrid converter of the present application. Compared with the prior art, the present application no longer requires an additional DC capacitor connected to the ground, and can achieve the flying capacitor voltage being stable at V in any working mode. , Figure 11 ,

[0049] ,

[0051] , ,

[0050] , , , Figure 10 , Figure 12 The balance control of 1 / 2 reduces the complexity of circuit design; at the same time, this application can be extended to any phase without restricting whether the phases overlap, eliminating the limitations of the prior art applied to even phases and the working range, and improving the flexibility of circuit design. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0040] Figure 1 It is a schematic structural diagram of an existing cross-connected capacitor buck converter;

[0041] Figure 2 It is a schematic structural diagram of an existing multi-inductor hybrid buck converter;

[0042] Figure 3 It is an evolution process diagram of the multi-phase hybrid converter according to an embodiment of this application;

[0043] Figure 4 It is a schematic structural diagram of a multi-phase hybrid converter provided by an embodiment of this application;

[0044] Figure 5 It is a working state diagram of the multi-phase hybrid converter provided by an embodiment of this application; <000开0241>

[0045] Figure 6 It is a working principle diagram of the multi-phase hybrid converter provided by an embodiment of this application when the duty cycle D < 0.25;

[0046] Figure 7 It is a working principle diagram of the multi-phase hybrid converter provided by an embodiment of this application when 0.25 < D < 0.5;

[0047] Figure 8 It is a schematic structural diagram of a multi-phase hybrid converter provided by another embodiment of this application;

[0048] Figure 9 It is a schematic diagram of the process of charging the unoperated flying capacitor provided by an embodiment of this application;

[0049] Figure 10 It is a circuit diagram of the charging control signal generation circuit provided by an embodiment of this application;

[0050] Figure 11 It is a steady-state operation test diagram of the multi-phase hybrid converter provided by an embodiment of this application;

[0051] Figure 12 It is a working flying capacitor charging test diagram of the multi-phase hybrid converter provided by an embodiment of this application.

[0052] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0053] The present invention will be further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may 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. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions, and for those skilled in the art, it is not necessary to describe these related operations in detail. They will fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0054] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0055] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally a class, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated before and after are in an "or" relationship. The "connection" and "connection" mentioned in this application, unless otherwise specified, include direct and indirect connections (connections).

[0056] Figure 1 Schematic diagram of the structure of the existing cross-connected capacitor buck converter. Figure 1As shown in the figure, the cross-connected capacitors in the buck converter act as energy storage elements in the circuit and participate in the energy storage and release process together with the inductor. At the same time, the cross-capacitors also help smooth the output voltage, reduce voltage fluctuations and noise. By carefully designing the layout and parameters of the cross-capacitors, the efficiency and performance of the converter can also be optimized.

[0057] Figure 2 FIG. 1 is a structural diagram of an existing multi-inductor hybrid buck converter. Figure 2 As shown in (a), the hybrid buck converter under this structure cannot overlap between phases when working, such as Figure 2 As shown in (b) and (c), if overlapped, the voltage of the switch node will increase, resulting in overvoltage. This non-overlapping characteristic will reduce the range of the duty cycle D as the number of phases increases, resulting in a decrease in the output range as the number of phases increases, limiting the operating range of the converter. At the same time, as Figure 2 As shown in (d), when there is an error in the duty cycle D between phases, the flying capacitor voltage will be offset, requiring additional circuitry for calibration, which undoubtedly increases the complexity of the circuit.

[0058] Furthermore, when implementing a multi-phase buck converter with cross-connected capacitors, if one phase fails for some reason, two inductors in the converter will be unable to deliver current to the load, reducing converter efficiency at high loads. Furthermore, when the converter operates at low load currents, the inactive flying capacitors will leak due to parasitic parameters, eventually causing the flying capacitor voltage to drop to zero, resulting in overvoltage on the power switch.

[0059] Therefore, an embodiment of the present application proposes a multi-phase hybrid converter to solve the technical problems that the existing multi-phase hybrid converter is easily affected and restricted by working conditions in the process of achieving flying capacitor self-balancing based on cross-connected capacitors, and the circuit design is complex, which is not conducive to the normal operation of the converter.

[0060] Figure 3 This is a diagram of the evolution of the multi-phase hybrid converter according to the embodiment of the present application. Figure 3 As shown, the present application is based on an existing cross-connected capacitor buck converter. By splitting the two high-voltage power switches in the prior art cross-connected capacitor buck converter into two low-voltage power switches and connecting them to a DC node, a flying capacitor is connected across the connection node between the upper and lower groups of power switches to obtain a phase unit with two completely symmetrical sub-converters. The phase units are then connected in parallel at the DC node to obtain the multi-phase hybrid converter of the present application. Therefore, the multi-phase hybrid converter of the present application can be expanded to any N phases, and the DC node VDC does not require a DC capacitor connected to ground.

[0061] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0062] Figure 4 This is a schematic diagram of the structure of a multi-phase hybrid converter provided by an embodiment of the present application. Figure 4 As shown, the multi-phase hybrid converter provided by the embodiment of the present application includes an input end 100 , an output end 200 , a phase output module 300 and an output circuit 400 .

[0063] In this embodiment, the input terminal 100 is used to receive the input voltage V IN , the output terminal 200 is connected to the load, and is used to IN Provides output voltage V to the load OUT .

[0064] The phase output module 300 includes a plurality of phase units 310 connected in parallel at a DC node. The phase output module 300 is used to output a voltage V OUT and input voltage V IN , generating a control signal to output multiple phases of output current. It should be noted that the number of phase units 310 is arbitrary, and can be an even number or an odd number, and the phases between each phase unit 310 can overlap or not overlap.

[0065] In this embodiment, each phase unit 310 includes a power switch circuit 3101, a flying capacitor 3102, and a control circuit 3103 connected in sequence. The power switch circuit 3101 includes a drive circuit and a power switch tube group. The power switch tube group is connected to the input terminal 100 and receives the input voltage V IN ; Flying capacitor 3102 is connected to the connection node of the power tube group; the control circuit 3103 is connected to the input terminal 100, the output terminal 200 and the power switch circuit 3101 respectively, and the control circuit 3103 is used according to the input voltage V IN , output voltage V OUT and the preset reference voltage V REF , generating non-overlapping control signals, and controlling the on or off of the power switch tube group through the driving circuit in the power switch circuit 3101 to achieve the output voltage V OUT of adjustment.

[0066] In some embodiments, such as Figure 4 As shown, for phase PhaseA, the power switch tube group in the power switch circuit 3101 includes the first power switch tubes M connected in series in sequence. A1, the second power switch tube M A2 , the third power switch tube M A3 and the fourth power switch tube M A4 , that is, the first power switch tube M A1 The first end of the second power switch tube M is connected to the input end 100. A2 The first end of the first power switch tube M A1 The second end of the third power switch tube M A3 The first end of the second power switch tube M A2 The second end of the fourth power switch tube M A4 The first end of the third power switch tube M A3 The second end of the fourth power switch tube M A4 The second end of the first power switch tube M is grounded. A1 and the second power switch tube M A2 The connection point of the first switch node is the third power switch tube M A3 and the fourth power switch tube M A4 The connection point of is the second switching node.

[0067] For phase PhaseA, the flying capacitor 3102 is the flying capacitor C FA The upper plate is connected to the first switch node, and the lower plate is connected to the second switch node.

[0068] In some embodiments, for phase Phase A, the driving circuit in the power switch circuit 3101 includes a first power switch tube M A1 , the second power switch tube M A2 , the third power switch tube M A3 and the fourth power switch tube M A4 The driving unit corresponds to each other. Specifically, the driving circuit includes a level shifter LS1 and a gate driver GD1 connected in series, a level shifter LS2 and a gate driver GD2 connected in series, a level shifter LS3 and a gate driver GD3 connected in series, and a delayer DLY and a gate driver GD4 connected in series. Specifically, the input end of the level shifter LS1 is used to receive the control signal of the first power switch tube M. A1 The first control signal of the gate driver GD1 is connected to the first power switch tube M A1 Similarly, the level shifter LS2 and the gate driver GD2, the level shifter LS3 and the gate driver GD3, the delayer DLY and the gate driver GD4 are respectively used to control the second power switch tube M A2 , the third power switch tube M A3 and the fourth power switch tube M A4 .

[0069] The output circuit 400 includes a plurality of output inductors L and output capacitors C O , wherein the output inductors correspond to the phase units 310 one by one, the first end of each output inductor L is connected to the second switch node in the corresponding phase unit 310, and the second end of each output inductor is connected in common to form an inductor connection node; the first end of the output capacitor is connected to the inductor connection node to provide an output voltage V OUT , the second end of the output capacitor is grounded.

[0070] like Figure 4 As shown, in some embodiments, for phase PhaseA, the output inductor L A The first end of the output inductor L is connected to the second switch node in phase PhaseA. For phase PhaseB, the output inductor L B The first end of the output inductor L is connected to the second switching node in phase PhaseB, ..., and the second ends of all output inductors L are connected in common.

[0071] Figure 5 This is a working state diagram of the multi-phase hybrid converter provided in the embodiment of the present application. For the multi-phase hybrid converter of the embodiment of the present application, a four-phase hybrid converter is taken as an example, wherein the working states include single phase working, two phases working, three phases working, four phases working or four phases not working. X-4P In this way, X means that the inductor of phase X is charging, and the number 4 means that there are 4 phases working. For example, Figure 5 (a) is S A-4P Working state, that is, an output inductor is charging (output inductor L A charging), the remaining output inductors are in discharge (L B 、L C and L D Equivalent circuit diagram of discharge); Figure 5 (b) is S AB-4P Working state, that is, the two output inductors are charging (output inductor L A and L B charging), the remaining output inductors are in discharge (output inductor L C and L D Equivalent circuit diagram of discharge); Figure 5 (c) is S 0-4P Working state, that is, all output inductors are in discharge (output inductor L A 、L B 、L C and L D Equivalent circuit diagram of (discharged) Figure 5 (d) is S ALL-4P Working state, that is, all output inductors are in charging (output inductor L A, L B , L C and L D are all charged) equivalent circuit diagram.

[0072] The following combines with the equivalent circuit diagram of the working state of the multi-phase hybrid converter to further illustrate the process of the multi-phase hybrid converter of the present application embodiment realizing flying capacitor automatic balancing.

[0073] In the multi-phase hybrid converter provided by the embodiment of the present application, when the duty cycle D < 0.25 or 0.25 < D < 0.5, each phase unit 310 can achieve automatic balancing through its own flying capacitor.

[0074] Figure 6 This is the working principle diagram of the multi-phase hybrid converter provided by the embodiment of the present application when the duty cycle D < 0.25. As Figure 6 shown, when the duty cycle D < 0.25, the working states of the multi-phase hybrid converter of this embodiment are successively S A-4P →S 0-4P →S B-4P →S 0-4P →S C-4P →S 0-4P →S D-4P →S 0-4P . In state S A-4P , C FA and C FB (or C FC , C FD ) are in series, and the formula V CFA +V CFB (or V CFC , V CFD ) = V IN can be obtained. In state S 0-4P , the four capacitors are in parallel, and the formula V CFA = V CFB = V CFC = V CFD can be obtained. From these two formulas, it can be deduced that all flying capacitor voltages are equal to V IN / 2, realizing the automatic balancing of the flying capacitor.

[0075] Figure 7 This is the working principle diagram of the multi-phase hybrid converter provided by the embodiment of the present application when the duty cycle 0.25 < D < 0.5. As Figure 7 shown, when the duty cycle 0.25 < D < 0.5, the working states of the multi-phase hybrid converter of this embodiment are successively S A-4P →S AB-4P →S B-4P →S BC-4P →S C-4P →SCD-4P →S D-4P →S DA-4P In state S A-4P When V CFA +V CFB (or V CFC , V CFD )=V IN ; In state S A-4P When V CFB +V CFC (or V CFD )=V IN ; From these two formulas, it can be deduced that all flying capacitor voltages are equal to V IN / 2.

[0076] It should be noted that the traditional four-inductor hybrid buck converter cannot operate under the condition of D>0.25. However, the multi-phase hybrid converter provided in the embodiment of the present application can operate under phase overlap due to its different flying capacitor connection structure, which broadens the operating range of the converter. That is, regardless of whether the phases overlap (whether D is greater than 0.25), the flying capacitors can be automatically balanced.

[0077] Figure 8 This is a structural diagram of a multi-phase hybrid converter provided by another embodiment of the present application. Figure 8 As shown, based on any of the above embodiments, the control circuit 3103 in each phase unit 310 of the multi-phase hybrid converter provided in the embodiment of the present application includes a control circuit including a current detection circuit, a synchronous hysteresis controller, a dead zone control circuit and a flying capacitor power-on control circuit.

[0078] In this embodiment, for phase PhaseA, the current detection circuit is connected to the second switch node and the output capacitor respectively, and the current sampling circuit is used to detect the voltage V at the second switch node. XA and the output voltage V OUT , get the output inductance L A Peak and valley limits.

[0079] The synchronous hysteresis controller is connected to the current detection circuit and the output capacitor respectively. The synchronous hysteresis controller is used to adjust the output voltage V OUT , preset reference voltage V REF As well as the peak limit or valley limit, a driving control signal is generated under the control of an external clock.

[0080] The dead zone control circuit is connected to the synchronous hysteresis controller and is used to perform interleaving processing on the drive control signal to generate non-overlapping control signals to control the on or off of the power switch tube group in the power switch circuit 3101.

[0081] The flying capacitor power-on control circuit is used to generate a flying capacitor power-on control signal in response to an external instruction before the multi-phase hybrid converter operates, so as to pre-charge the flying capacitor.

[0082] For hybrid multi-phase converters, when the load current is low, some phases can be shut down to improve the overall converter efficiency. However, in traditional hybrid multi-phase converters, the flying capacitors in the inactive phases will leak due to the presence of some parasitic parameters. Eventually, the flying capacitor voltage will drop to zero, causing some power switches to overvoltage. In this case, the inactive flying capacitors need to be recharged to maintain balance and avoid overvoltage in the power switches.

[0083] In some embodiments, in order to alleviate the overvoltage situation of the power switch tube, a clamped power switch tube is used. Due to its own structure, the flying capacitor will be clamped at V IN / 2-V OUT -V D , where V D It is the conduction voltage of the diode inside the power switch tube. This clamping mechanism can greatly alleviate the overvoltage situation of the tube, but there are still risks.

[0084] Therefore, in some embodiments, a non-working flying capacitor power replenishment control circuit is further added to the control circuit 3103 .

[0085] In this embodiment, the non-operating flying capacitor power replenishment control circuit is used to generate a power replenishment control signal based on an external power replenishment enable signal. When a preset power replenishment condition is met, the power switch circuit 3101 in the non-operating phase unit 310 is controlled to be turned on, so that the flying capacitor in the non-operating phase unit 310 is connected in parallel with the flying capacitor in the operating phase unit 310, so that the flying capacitor in the non-operating phase unit 310 is charged from the flying capacitor in the operating phase unit 310 to the flying capacitor in the non-operating phase unit 310.

[0086] Figure 9 This is a schematic diagram of the charging process of an inoperative flying capacitor provided by an embodiment of the present application. Figure 9 As shown, taking the multi-phase hybrid converter of this embodiment as an example, assuming that phase PhaseB is the working phase and phase PhaseA is the non-working phase, it is necessary to pass the flying capacitor C in phase PhaseB. FB For the flying capacitor C in Phase A FA To supplement power, the second power switch tube M in phase PhaseA can be controlled by the supplement power control signal. A2 、Flying capacitor C FA and the fourth power switch tube M A4 , and the second power switch tube M in phase PhaseB B2、Flying capacitor C FB and the fourth power switch tube M B4 Form a loop to realize the flying capacitor C in the working phase PhaseB FB To the flying capacitor C in the non-operating phase PhaseA FA Charge.

[0087] In some embodiments, when there are multiple non-working phase units 310, the flying capacitors in the same working phase unit 310 can be selected to charge the flying capacitors in multiple non-working phase units 310, or the flying capacitors in different working phase units 310 can be selected to charge the flying capacitors in multiple non-working phase units 310 separately, so as to realize the charging of the non-working flying capacitors.

[0088] For example, taking the multi-phase hybrid converter of this embodiment as an example, assuming that phases PhaseA and PhaseB are non-working phases, and phases PhaseC and PhaseD are working phases, the flying capacitor C in phase PhaseA is FA and the flying capacitor C in PhaseB FB When replenishing power, you can also select the flying capacitor C of phase PhaseC FC To supplement the power of both, you can also choose the flying capacitor C of phase PhaseC FC To the flying capacitor C in the non-operating phase PhaseA FA To charge the flying capacitor C of phase D FD To the flying capacitor C in the non-operating phase PhaseB FB Charge.

[0089] In some embodiments, the multi-phase hybrid converter provided in this embodiment also includes a power replenishment control signal generating circuit, which is connected to the dead zone control circuit, and is used to receive the control signal of the phase unit 310 that controls the operation, perform frequency division and delay processing on the control signal, and obtain a power replenishment control signal that meets the preset power replenishment conditions.

[0090] In some embodiments, the power replenishment control signal generating circuit is sequentially connected to a frequency divider and a pulse generator.

[0091] In which, the frequency divider includes N D flip-flops cascaded in sequence, where N is a positive integer; the pulse generator includes a delayer, an inverter and an AND logic gate; in which, the input end of the first-stage D flip-flop is used to receive a non-overlapping control signal for controlling the operation of the selected phase unit 310, the input end of the delayer is connected to the output end of the N-stage D flip-flop; the input end of the inverter is connected to the output end of the delayer; the first input end of the AND logic gate is connected to the output end of the N-stage D flip-flop, the second input end is connected to the output end of the inverter, and the output end is used to output a power replenishment control signal.

[0092] Figure 10 This is a circuit diagram of a power supply control signal generating circuit provided by an embodiment of the present application. Figure 10 As shown, the frequency divider of the power supply control signal generating circuit provided in some embodiments includes 8 D flip-flops cascaded in sequence. Figure 10 The illustrated power-supply control signal generating circuit assumes that the control signal for the phase unit 310 is a PWM signal. The PWM signal is used as the input of the frequency divider. The PWM signal then passes through the pulse generating circuit to generate a PWM_128 signal that is divided 128 times and delayed. The PWM_128 signal is used as the power-supply control signal.

[0093] In some embodiments, the preset recharging condition is that an externally input recharging enable signal is at a high level. That is, when the recharging enable signal is at a high level, the PWM_128 signal is used as the recharging control signal to control the power switch circuit 3101 in the inactive phase unit 310 to conduct, so that the flying capacitor in the inactive phase unit 310 is connected in parallel with the flying capacitor in the active phase unit 310, so that the flying capacitor in the active phase unit 310 is charged from the flying capacitor in the active phase unit 310 to the flying capacitor in the inactive phase unit 310. In this embodiment, the inactive flying capacitor is recharged once every 128 switching cycles.

[0094] In some embodiments, such as Figure 8 As shown, the control circuit 3103 also includes a channel selection control circuit.

[0095] The channel selection circuit is connected to the inoperative flying capacitor power replenishment control circuit, the dead zone control circuit, and the flying capacitor power-up control circuit, respectively. The selection control circuit is used to selectively activate the flying capacitor in the corresponding inoperative phase unit 310 for power replenishment according to the power replenishment control signal; and to selectively activate the power switch tube group in the corresponding power switch circuit 3101 to turn on or off according to the non-overlapping control signal; and, according to the flying capacitor power-up control signal, selectively activate the flying capacitor in the corresponding phase unit 310 for pre-charging.

[0096] In some embodiments, such as Figure 8As shown, based on any of the above embodiments, in the multi-phase hybrid converter provided by the embodiment of the present application, each phase unit 310 further includes a compensation circuit 3104 .

[0097] In this embodiment, the compensation circuit 3104 is connected to the output terminal 200 and the control circuit 3103 respectively. The compensation circuit 3104 is used to compare the output voltage V OUT and reference voltage V REF , for the output voltage V OUT The error is amplified and then output.

[0098] In some embodiments, the compensation circuit 3401 includes a resistor R1, an error amplifier EA, a capacitor C1, a resistor R2, and a capacitor C2. The first end of the resistor R1 is connected to the first end of the compensation circuit; the non-inverting input of the error amplifier EA is connected to the second end of the compensation circuit, the inverting input of the error amplifier EA is connected to the second end of the resistor R1, and the output of the error amplifier EA is connected to the output of the compensation circuit; the capacitor C1 and the resistor R2 are connected in series, the first end of the capacitor C1 is connected to the inverting input of the error amplifier EA, the second end of the resistor R2 is connected to the output of the error amplifier EA; the first end of the capacitor C2 is connected to the first end of the capacitor C1, and the second end of the capacitor C2 is connected to the second end of the resistor R2.

[0099] Figure 11 This is a steady-state test diagram of the multi-phase hybrid converter provided in the embodiment of the present application. Figure 11 As shown, the multi-phase hybrid converter provided in the embodiment of the present application can arbitrarily configure the switch node waveform of the hybrid buck converter in steady state operation. The switch node voltage of each phase is calculated according to V CF →0→V IN -V CF →0. From the test diagram, it can be found that the amplitude of the square wave signal of the switch node of each phase is the same, indicating that V IN -V CF =V CF , which is V CF =V CF / 2. The proposed structure achieves automatic balancing of the flying capacitor when D<0.25 and D>0.25.

[0100] Figure 12 This is a test diagram of the flying capacitor charging of the multi-phase hybrid converter provided in the embodiment of the present application. Figure 12As shown in the figure, the test results of leakage, clamping, and recharging of the non-operating flying capacitors when the multi-phase hybrid converter provided by the embodiment of the present application operates at a 12V input voltage. When the recharging enable signal is low, the non-operating flying capacitors begin to leak, the voltage gradually drops, and they are clamped. When the recharging enable signal is high, the non-operating flying capacitors begin to recharge, and their voltage quickly returns to half the input voltage of 6V.

[0101] In summary, the multi-phase hybrid converter provided by the embodiment of the present application is achieved by splitting the two high-voltage power switch tubes in the cross-connected capacitor buck converter in the prior art into two low-voltage power switch tubes and connecting them to the DC node. The flying capacitor is connected across the connection node of the upper and lower groups of power switch tubes to obtain a phase unit with two completely symmetrical sub-converters. The phase units are then connected in parallel at the DC node to expand the multi-phase hybrid converter of the present application. Compared with the prior art, the present application no longer requires an additional DC capacitor connected to the ground, and can achieve the flying capacitor voltage being stable at V in any operating mode. IN / 2 balance control reduces the complexity of circuit design; at the same time, the present application can be extended to any phase, and there is no restriction on whether the phases overlap, eliminating the limitations of the existing technology applied to even phases and working ranges, and improving the flexibility of circuit design.

[0102] At the same time, based on the existing circuit structure, a non-working flying capacitor power replenishment control circuit is added. When the preset power replenishment conditions are met, the power switch circuit in the non-working phase unit is controlled to be turned on, so that the flying capacitor in the non-working phase unit is connected in parallel with the flying capacitor in the working phase unit, and the flying capacitor in the non-working phase unit is charged by the flying capacitor in the working phase unit. On the basis of circuit reuse, the overvoltage of the power switch tube is alleviated.

[0103] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can make several simple deductions, modifications or substitutions based on the ideas of the present invention without departing from the scope of protection of the purpose of the present application and the claims. All of these are within the protection of the present application.

Claims

1. A multi-phase hybrid converter, characterized in that: Comprising: An input terminal for receiving an input voltage; An output terminal connected to a load for providing an output voltage to the load according to the input voltage; A phase output module including a plurality of parallel-connected phase units for generating a control signal according to the output voltage and the input voltage to output output currents of multiple phases; each of the phase units includes a power switch circuit, a flying capacitor, and a control circuit connected in sequence; The control circuit is configured to generate a non-overlapping control signal according to the input voltage, the output voltage, and a preset reference voltage to control the on or off of the power switch circuit to adjust the output voltage; Wherein, the power switch circuit includes a first power switch transistor, a second power switch transistor, a third power switch transistor, and a fourth power switch transistor connected in series in sequence; the upper plate of the flying capacitor is connected to a first switching node where the first power switch transistor and the second power switch transistor are connected, and the lower plate of the flying capacitor is connected to a second switching node where the third power switch transistor and the fourth power switch transistor are connected; An output circuit including a plurality of output inductors and output capacitors; the output inductors correspond to the phase units one by one, the first end of the output inductor is connected to the second switching node in its corresponding phase unit, and the second ends of the output inductors are commonly connected to form an inductor connection node; the first end of the output capacitor is connected to the inductor connection node for providing an output voltage, and the second end of the output capacitor is grounded; The control circuit includes an unoperated flying capacitor charging control circuit; the unoperated flying capacitor charging control circuit is configured to generate a charging control signal according to an external charging enable signal, and when a preset charging condition is satisfied, control the power switch circuit in the unoperated phase unit to conduct, so that the flying capacitor in the unoperated phase unit is connected in parallel with the flying capacitor in the operated phase unit, so as to realize charging the flying capacitor in the unoperated phase unit through the flying capacitor in the operated phase unit.

2. The multi-phase hybrid converter according to claim 1, characterized in that: When the duty cycle D of the multi-phase hybrid converter is less than 0.25 or 0.25 < D < 0.5, each of the phase units can achieve automatic balance through its own flying capacitor.

3. The multi-phase hybrid converter according to claim 1, wherein: When there are multiple unoperated phase units, select the flying capacitor in the same operated phase unit to charge the flying capacitors in the multiple unoperated phase units; Alternatively, select the flying capacitors in different operated phase units to charge the flying capacitors in the multiple unoperated phase units separately.

4. The multi-phase hybrid converter according to claim 3, characterized in that: It further includes a charging control signal generation circuit; The input end of the charging control signal generation circuit is configured to receive a control signal for controlling the operated phase unit, perform frequency division delay processing on the control signal, and obtain a charging control signal that satisfies the preset charging condition.

5. The multi-phase hybrid converter according to claim 4, characterized in that: When selecting the flying capacitors in different operated phase units to charge the flying capacitors in the multiple unoperated phase units separately, the charging control signal generation circuit includes a plurality of charging control signal generation units; Each of the charging control signal generation units corresponds to the selected operated phase unit one by one.

6. The multi-phase hybrid converter according to claim 4, characterized in that: The power replenishment control signal generating circuit includes a frequency divider and a pulse generator connected in sequence; The frequency divider includes N D flip-flops cascaded in sequence; the pulse generator includes a delay, an inverter and an AND logic gate; N is a positive integer; Among them, the input end of the first-level D-type flip-flop is used to receive a non-overlapping control signal for controlling the operation of the selected working phase unit, the input end of the delay device is connected to the output end of the N-level D-type flip-flop; the input end of the inverter is connected to the output end of the delay device; the first input end of the AND logic gate is connected to the output end of the N-level D-type flip-flop, the second input end is connected to the output end of the inverter, and the output end is used to output a power replenishment control signal.

7. The multi-phase hybrid converter according to claim 1, characterized in that: The control circuit includes a current detection circuit, a synchronous hysteresis controller, a dead zone control circuit and a flying capacitor power-on control circuit; The current detection circuit is connected to the second switch node and the output capacitor respectively; The current sampling circuit is used to obtain a peak limit value and a valley limit value of the output inductor according to the voltage at the second switch node and the output voltage; The synchronous hysteresis controller is connected to the current detection circuit and the output capacitor respectively; The synchronous hysteresis controller is used to generate a drive control signal under the control of an external clock according to the output voltage, a preset reference voltage and a peak limit or a valley limit; The dead zone control circuit is connected to the synchronous hysteresis controller; the dead zone control circuit is used to interleave the drive control signal to generate a non-overlapping control signal to control the on or off of the power switch circuit; The flying capacitor power-on control circuit is used to generate a flying capacitor power-on control signal in response to an external instruction before the multi-phase hybrid converter operates, so as to pre-charge the flying capacitor.

8. The multi-phase hybrid converter according to claim 7, characterized in that: The control circuit further includes a channel selection control circuit; The channel selection circuit is connected to the non-working flying capacitor power replenishment control circuit, the dead zone control circuit and the flying capacitor power-on control circuit respectively; the selection control circuit is used to selectively activate the flying capacitor in the corresponding non-working phase unit for power replenishment according to the power replenishment control signal; And, it is used to selectively activate the power switch tube in the corresponding power switch circuit to turn on or off according to the non-overlapping control signal; and selectively activate the flying capacitor in the corresponding phase unit for pre-charging according to the flying capacitor power-on control signal.

9. The multi-phase hybrid converter according to claim 1, characterized in that: The phase unit further includes a compensation circuit; The first input terminal of the compensation circuit is used to receive the output voltage output by the output circuit, the second input terminal is used to receive a preset reference voltage, and the output terminal of the compensation circuit is used to output an error amplified signal; The compensation circuit includes a resistor R1, an error amplifier EA, a capacitor C1, a resistor R2 and a capacitor C2; The first end of the resistor R1 is connected to the first end of the compensation circuit; The non-inverting input terminal of the error amplifier EA is connected to the second terminal of the compensation circuit, the inverting input terminal of the error amplifier EA is connected to the second terminal of the resistor R1, and the output terminal of the error amplifier EA is connected to the output terminal of the compensation circuit; The capacitor C1 and the resistor R2 are connected in series, a first end of the capacitor C1 is connected to the inverting input end of the error amplifier EA, and a second end of the resistor R2 is connected to the output end of the error amplifier EA; A first end of the capacitor C2 is connected to a first end of the capacitor C1 , and a second end of the capacitor C2 is connected to a second end of the resistor R2 .

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