Multi-phase power supply and control circuit and control method thereof

Abstract

The invention discloses a multi-phase power supply and a control circuit and a control method thereof. The multi-phase power supply includes a multi-phase power conversion circuit. The control circuit comprises a phase enabling module which is used for generating a plurality of phase enabling signals according to a plurality of PWM signals and a plurality of zero-cross detection signals; and the first logic module is used for generating a plurality of switch control signals of the multi-phase power conversion circuit according to the plurality of PWM signals and the plurality of phase enable signals, and when the selected phase power conversion circuit is subjected to phase reduction, the phase enable module outputs the switch control signals after the phase current of the selected phase power conversion circuit passes zero. The selected phase enable signal is flipped from an active state to an inactive state, thereby delaying turn-off of the selected phase power conversion circuit. According to the multi-phase power supply control circuit, the turn-off time of the selected phase power conversion circuit is delayed to the zero-crossing time of the phase current during phase reduction, so that inductive current oscillation during phase reduction can be effectively reduced, and the output stability of a system during phase number change is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies, and more specifically, to a multi-phase power supply and a control circuit and a control method thereof. Background Art

[0002] In CPU power supply applications, in order to cope with increasingly complex data processing and logic calculation functions, the CPU requires more and more power from the power supply, and the load current slew rate encountered by the power supply system during operation is also getting higher and higher. In order to respond to the CPU's demand for power supply capacity, multi-phase power supply systems are currently used in CPU power supply systems.

[0003] Multiphase power supply is a technology that connects multiple power conversion circuits in parallel and interleaves them. Each channel has a corresponding power switch tube and inductor, and the switching modulation process is distributed to different phases to achieve the adjustment and control of the power supply. The PWM (pulse width modulation) signals between phases in a multiphase power supply can be the same or staggered by a certain phase, so that the fluctuation frequency seen by the output and input is the product of the switching frequency in each phase and the number of phases, thereby reducing the need for filter capacitors and reducing the current impact on the input, while speeding up the response to load changes.

[0004] In a multi-phase power supply system, the control circuit opens a corresponding number of power conversion circuits according to the load current to share the current provided to the load. The control circuit uses an analog-to-digital converter (ADC) to sample the current information of each phase, performs analog-to-digital conversion to obtain the average output current of each phase, and judges the load change based on the change in the average output current. When the load is heavy, the control circuit turns on the power conversion circuits of all phases to respond to rapid load changes with extremely high bandwidth. When the load is light, the control circuit gradually reduces the number of working phases of the power conversion circuit according to the load current to reduce power consumption and save energy.

[0005] However, in the existing multi-phase power supply, when the load current decreases to a predetermined threshold value, the control circuit immediately shuts down the selected phase power conversion circuit when performing the phase reduction action. Since there is still phase current in the selected phase power conversion circuit before the phase reduction, the immediate shutdown of the selected phase power conversion circuit will cause output current fluctuation and oscillation, and in severe cases even cause subsequent wrong phase increase, affecting the stability of system operation. Summary of the invention

[0006] In view of the above problems, the object of the present invention is to provide a multi-phase power supply and its control circuit and control method, which are used to delay the shutdown of the selected phase power conversion circuit when reducing the phase, so as to reduce the fluctuation of the total inductor current and improve the output stability when the number of phases changes.

[0007] According to one aspect of the present invention, a control circuit of a multi-phase power supply is provided, wherein the multi-phase power supply includes a multi-phase power conversion circuit, the control circuit includes a plurality of phase control circuits, each phase control circuit controls a corresponding phase power conversion circuit, and each phase control circuit includes: a PWM signal generating module, generating a PWM signal of the corresponding phase power conversion circuit according to the output voltage of the multi-phase power supply; a zero-crossing detection module, generating a zero-crossing detection signal of the corresponding phase power conversion circuit according to a phase current sampling signal of the corresponding phase power conversion circuit; a phase enable module, generating a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal; and a first logic module, generating a switch control signal of the corresponding phase power conversion circuit according to the PWM signal and the phase enable signal, the phase enable module calculates the number of phases to be turned on according to the multi-phase current sampling signal, and when the number of phases of the multi-phase power conversion circuit decreases, the phase enable module delays turning off the corresponding phase power conversion circuit according to the corresponding phase enable signal when the phase current sampling signal of the corresponding phase power conversion circuit decreases from positive current to zero, thereby realizing phase reduction control of the multi-phase power conversion circuit.

[0008] Optionally, the phase enable module includes: a phase number calculation module, which calculates the number of phases to be turned on according to the multi-phase current sampling signal; a phase control module, which generates a phase control signal of the corresponding phase according to the phase number, the zero-crossing detection signal of the corresponding phase, and the PWM signal of the corresponding phase; and a second logic module, which generates the phase enable signal of the corresponding phase according to the phase control signal of the corresponding phase and the zero-crossing detection signal of the corresponding phase, and the phase enable signal turns on or off the corresponding phase power conversion circuit.

[0009] Optionally, when the PWM signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state. When the phase control signal is in an invalid state, the first switching device controlled by the corresponding phase power conversion circuit is kept turned off.

[0010] Optionally, the total inductor current of the multi-phase power conversion circuit is calculated based on the multi-phase current sampling signal, and the total inductor current represents the load current of the multi-phase power supply. When the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control circuit includes the following stages in sequence: (1) the load current decreases and triggers the phase number to decrease, the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state; (2) the corresponding PWM signal changes from an invalid state to an effective state, and the inductor of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in an effective state, the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state. The first switching device in the corresponding phase power conversion circuit is in the on state and the second switching device is in the off state, and the corresponding phase current sampling signal changes from negative current to positive current; (3) the corresponding PWM signal changes from the valid state to the invalid state, and at the falling edge of the corresponding PWM signal and when the corresponding phase current sampling signal is a positive current, the corresponding phase control signal becomes an invalid state. During the period when the corresponding PWM signal is in the invalid state, the first switching device in the corresponding phase power conversion circuit is in the off state and the second switching device is in the on state, and the corresponding phase current sampling signal decreases from positive current to zero; (4) the corresponding phase control signal is in the invalid state, and when the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switching device and the second switching device in the corresponding phase power conversion circuit to be turned off, and the corresponding phase power conversion circuit is turned off.

[0011] Optionally, the phase enable module includes: a phase number calculation module, which calculates the number of phases to be turned on according to the multi-phase current sampling signal; a zero-crossing shielding module, which generates a zero-crossing detection shielding signal of the corresponding phase according to the PWM signal of the corresponding phase; a phase control module, which generates a phase control signal of the corresponding phase according to the phase number, the zero-crossing detection signal of the corresponding phase, and the zero-crossing detection shielding signal of the corresponding phase; and a second logic module, which generates the phase enable signal of the corresponding phase according to the phase control signal of the corresponding phase and the zero-crossing detection signal of the corresponding phase, and the phase enable signal turns on or off the corresponding phase power conversion circuit.

[0012] Optionally, when the rising edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from an invalid state to a valid state; when the falling edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from a valid state to an invalid state after a delayed shielding time; when the zero-crossing detection shielding signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state, and when the phase control signal is in an invalid state, the first switching device in the corresponding phase power conversion circuit is kept turned off.

[0013] Optionally, the masking time period of the zero-crossing masking module is greater than the pulse width of the valid state of the PWM signal.

[0014] Optionally, the phase control module is used to perform a logical operation on the zero-crossing detection signal of the corresponding phase, the zero-crossing detection shielding signal of the corresponding phase and the phase number to obtain the phase control signal of the corresponding phase.

[0015] Optionally, when the zero-crossing detection signal of the corresponding phase power conversion circuit is invalid and the zero-crossing detection shielding signal is invalid, the phase control signal of the corresponding phase power conversion circuit is flipped from a valid state to an invalid state.

[0016] Optionally, the total inductor current of the multi-phase power conversion circuit is calculated according to the multi-phase current sampling signal, and the total inductor current represents the load current of the multi-phase power supply. When the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control circuit includes the following stages in sequence: (1) when the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state; (2) the corresponding PWM signal changes from an invalid state to an effective state, and the inductor of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in an effective state, the first switch device in the corresponding phase power conversion circuit is in an on state and the second switch device is in an on state. and the second switch device is in the off state, and the corresponding phase current sampling signal changes from negative current to positive current; (3) the corresponding PWM signal changes from a valid state to an invalid state, and when the falling edge of the corresponding PWM signal arrives, the corresponding phase control signal becomes an invalid state after the delay of the shielding time and the corresponding phase current sampling signal is a positive current. During the period when the corresponding PWM signal is in the invalid state, the first switch device in the corresponding phase power conversion circuit is in the off state and the second switch device is in the on state, and the corresponding phase current sampling signal decreases from positive current to zero; (4) the corresponding phase control signal is in the invalid state, and when the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switch device and the second switch device in the corresponding phase power conversion circuit to turn off, and the corresponding phase power conversion circuit is turned off.

[0017] Optionally, the second logic module includes an OR gate for performing a logical OR operation on the phase control signal and an inverted signal of the zero-crossing detection signal.

[0018] Optionally, the first logic module includes: a first AND gate, used to perform a logic AND operation on the PWM signal of the corresponding phase and the corresponding phase enable signal to generate a plurality of first switch control signals; and a second AND gate, used to perform a logic AND operation on the inverted signal of the PWM signal of the corresponding phase and the corresponding phase enable signal to generate a plurality of second switch control signals, and the corresponding phase power conversion circuit respectively receives the corresponding first switch control signal and the corresponding second switch control signal.

[0019] Optionally, the zero-crossing detection module is used to compare the phase current sampling signal of the corresponding phase power conversion circuit with a current reference signal to obtain the zero-crossing detection signal.

[0020] Optionally, the PWM signal generating module is used to compare the output voltage with a voltage reference signal to generate an error signal, and adjust the duty cycle of the PWM signal according to the error signal.

[0021] Optionally, phase subtraction is performed according to the serial number sorting of the multi-phase power conversion circuit.

[0022] According to another aspect of the present invention, a multi-phase power supply is provided, comprising: the above-mentioned control circuit, used to generate multiple switch control signals; and a multi-phase power conversion circuit, which includes multiple switch circuits, the multiple switch circuits receive the corresponding switch control signals, and the output ends of the multiple switch circuits are coupled together to power the load.

[0023] According to another aspect of the present invention, a control method for a multi-phase power supply is provided, wherein the multi-phase power supply includes a multi-phase power conversion circuit, and the control method includes: generating a PWM signal of a corresponding phase power conversion circuit according to an output voltage of the multi-phase power supply; generating a zero-crossing detection signal of the corresponding phase power conversion circuit according to a phase current sampling signal of the corresponding phase power conversion circuit; generating a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal; and generating a switch control signal of the corresponding phase power conversion circuit according to the PWM signal and the phase enable signal, wherein the control method also includes: calculating the number of phases to be turned on according to the multi-phase current sampling signal, and when the number of phases of the multi-phase power conversion circuit decreases, the phase enable module delays shutting down the corresponding phase power conversion circuit according to the corresponding phase enable signal when the phase current sampling signal of the corresponding phase power conversion circuit decreases from positive current to zero, thereby realizing phase reduction control of the multi-phase power conversion circuit.

[0024] Optionally, generating a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal includes: calculating the number of phases to be turned on according to the multi-phase current sampling signal; generating a phase control signal of the corresponding phase according to the number of phases, the zero-crossing detection signal of the corresponding phase, and the PWM signal of the corresponding phase; and performing a logical OR operation on the phase control signal of the corresponding phase and the inverted signal of the zero-crossing detection signal of the corresponding phase to generate the phase enable signal of the corresponding phase, and the phase enable signal turns on or off the corresponding phase power conversion circuit.

[0025] Optionally, when the PWM signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state. When the phase control signal is in an invalid state, the first switching device of the corresponding phase power conversion circuit is kept turned off.

[0026] Optionally, the control method further includes: calculating a total inductor current of a multi-phase power conversion circuit according to the multi-phase current sampling signal, wherein the total inductor current represents a load current of a multi-phase power supply, and when a decrease in the load current triggers a decrease in the number of phases, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control method includes the following stages in sequence: (1) the load current decreases and triggers a decrease in the number of phases, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, and the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state; (2) the corresponding PWM signal changes from an invalid state to an effective state, and the inductor of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in an effective state, the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state. (1) when the first switching device is in the on state and the second switching device is in the off state, the corresponding phase current sampling signal changes from negative current to positive current; (2) when the first switching device is in the on state and the second switching device is in the off state, the corresponding phase current sampling signal changes from negative current to positive current; (3) when the corresponding PWM signal changes from the valid state to the invalid state, at the falling edge of the corresponding PWM signal and when the corresponding phase current sampling signal is positive current, the corresponding phase control signal changes to the invalid state, during the period when the corresponding PWM signal is in the invalid state, the first switching device in the corresponding phase power conversion circuit is in the off state and the second switching device is in the on state, and the corresponding phase current sampling signal decreases from positive current to zero; (4) when the corresponding phase control signal is in the invalid state and the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switching device and the second switching device in the corresponding phase power conversion circuit to turn off, and the corresponding phase power conversion circuit is turned off.

[0027] Optionally, generating a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal includes: calculating the number of phases to be turned on according to the multi-phase current sampling signal; generating a zero-crossing detection shielding signal of the corresponding phase according to the PWM signal of the corresponding phase; generating a phase control signal of the corresponding phase according to the number of phases, the zero-crossing detection signal of the corresponding phase, and the zero-crossing detection shielding signal of the corresponding phase; and performing a logical OR operation on the phase control signal of the corresponding phase and the inverted signal of the zero-crossing detection signal of the corresponding phase to generate the phase enable signal of the corresponding phase, and the phase enable signal turns on or off the corresponding phase power conversion circuit.

[0028] Optionally, when the rising edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from an invalid state to a valid state; when the falling edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from a valid state to an invalid state after a delayed shielding time; when the zero-crossing detection shielding signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state, and when the phase control signal is in an invalid state, the first switching device in the corresponding phase power conversion circuit is kept turned off.

[0029] Optionally, the masking time is greater than a pulse width of a valid state of the plurality of PWM signals.

[0030] Optionally, when the zero-crossing detection signal of the corresponding phase power conversion circuit is invalid and the zero-crossing detection shielding signal is invalid, the phase control signal of the corresponding phase power conversion circuit is flipped from a valid state to an invalid state.

[0031] Optionally, the control method further includes: calculating a total inductance current of a multi-phase power conversion circuit according to the multi-phase current sampling signal, wherein the total inductance current represents a load current of a multi-phase power supply, and when the load current decreases and triggers a decrease in the number of phases, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control method includes the following stages in sequence: (1) when the load current decreases and triggers a decrease in the number of phases, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state; (2) the corresponding PWM signal changes from an invalid state to an effective state, and the inductance of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in an effective state, the first switch device in the corresponding phase power conversion circuit is in an off state. The first switching device in the corresponding phase power conversion circuit is in the on state and the second switching device is in the off state, and the corresponding phase current sampling signal changes from negative current to positive current; (3) the corresponding PWM signal changes from the valid state to the invalid state, and when the falling edge of the corresponding PWM signal arrives, the corresponding phase control signal becomes invalid after the shielding time is delayed and the corresponding phase current sampling signal is positive current. During the period when the corresponding PWM signal is in the invalid state, the first switching device in the corresponding phase power conversion circuit is in the off state and the second switching device is in the on state, and the corresponding phase current sampling signal decreases from positive current to zero; (4) the corresponding phase control signal is in the invalid state, and when the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switching device and the second switching device in the corresponding phase power conversion circuit to turn off, and the corresponding phase power conversion circuit is turned off.

[0032] Optionally, generating the switch control signal of the corresponding phase power conversion circuit according to the PWM signal and the phase enable signal includes: performing a logic AND operation on the PWM signal of the corresponding phase and the corresponding phase enable signal to generate a plurality of first switch control signals; and performing a logic AND operation on the inverted signal of the PWM signal of the corresponding phase and the corresponding phase enable signal to generate a plurality of second switch control signals, and the corresponding phase power conversion circuit respectively receives the corresponding first switch control signal and the corresponding second switch control signal.

[0033] Optionally, generating the zero-crossing detection signal of the corresponding phase power conversion circuit according to the phase current sampling signal of the corresponding phase power conversion circuit includes: comparing the phase current sampling signal of the corresponding phase power conversion circuit with a current reference signal to obtain the zero-crossing detection signal.

[0034] Optionally, generating a PWM signal of a corresponding phase power conversion circuit according to the output voltage of the multi-phase power supply includes: comparing the output voltage with a voltage reference signal to generate an error signal, and adjusting a duty cycle of the PWM signal according to the error signal.

[0035] Optionally, phase subtraction is performed according to the serial number sorting of the multi-phase power conversion circuit.

[0036] In summary, in the multi-phase power supply and its control circuit and control method provided by the embodiment of the present invention, when the phase reduction operation is performed on the selected phase power conversion circuit in the multi-phase power supply, if the phase current sampling signal of the corresponding phase power conversion circuit is in the negative current period when the number of phases is reduced, the shutdown time of the selected phase power conversion circuit is delayed until the phase current sampling signal of the corresponding phase power conversion circuit becomes a positive current and decreases to zero. Similarly, if the phase current sampling signal of the corresponding phase power conversion circuit is in the positive current period when the number of phases is reduced, the shutdown time of the selected phase power conversion circuit is delayed until the current decreases from the positive current to zero. Compared with the solution of the conventional technology of immediately shutting down the corresponding phase power conversion circuit when the phase is reduced, the multi-phase power supply and its control circuit and control method provided by the embodiment of the invention can effectively reduce the inductor current oscillation occurring during the phase reduction operation, avoid the overshoot of the output voltage, and improve the stability of the circuit output. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0038] Figure 1 A schematic block diagram of a multi-phase power supply according to an embodiment of the present invention is shown;

[0039] Figure 2 Show Figure 1 A schematic block diagram of a control circuit in the multi-phase power supply shown;

[0040] Figure 3 Show Figure 2 A first example of a phase enable module in the control circuit shown;

[0041] Figure 4 Show Figure 2 A second example of a phase enable module in the control circuit shown;

[0042] Figure 5 The working waveform diagram of the multi-phase power supply control circuit according to the embodiment of the present invention is shown;

[0043] Figure 6 A total inductor current waveform diagram of a multi-phase power conversion circuit in a multi-phase power supply according to an embodiment of the present invention is shown;

[0044] Figure 7 A flow chart of a multi-phase power supply control method according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0045] Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, identical elements are represented by identical or similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown.

[0046] It should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit through electrical connection or electromagnetic connection. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected between" two nodes, it can be directly coupled or connected to another element or there can be an intermediate element, and the connection between the elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0047] It should be noted that, in this article, the switching device is a transistor that works in a switching mode to provide a current path, including one selected from a bipolar transistor or a field effect transistor. The first end and the second end of the switching device are respectively a high potential end and a low potential end on the current path, and the control end of the switching device is used to receive a drive signal to control the on and off of the transistor. In addition, in the present application, the description of the on and off of the power conversion circuit corresponds to the on and off of the main switching device that receives the input voltage in the power conversion circuit. For example, turning on the power conversion circuit corresponds to turning on the main switching device in the power conversion circuit to connect the energy storage element in the circuit to the input for charging and energy storage, and start to provide power output to the load (that is, generate a corresponding output voltage according to the input voltage); turning off the power conversion circuit corresponds to turning off the main switching device in the power conversion circuit to end the charging and energy storage state of the energy storage element in the circuit, and stop providing power output to the load.

[0048] Figure 1 A schematic block diagram of a multi-phase power supply according to an embodiment of the present invention is shown. The multi-phase power supply of the embodiment of the present invention includes a multi-phase power supply control circuit and a multi-phase power conversion circuit, the number of phases of the multi-phase power conversion circuit is, for example, N, N is an integer greater than 1, and the multi-phase power supply control circuit is used to control the conduction sequence of the multi-phase power conversion circuit and the charging time of the energy storage element to jointly provide an output voltage Vout.

[0049] Specifically, refer to Figure 1 The multi-phase power supply 100 includes N-phase parallel-coupled power conversion circuits 101 - 10N (N is the number of phases set in the multi-phase power supply, and N is an integer greater than 1), and a multi-phase power supply control circuit (hereinafter referred to as control circuit) 200.

[0050] Each phase power conversion circuit includes a first switch device T1 and a second switch device T2, and an inductor Lx. The first switch device T1 and the second switch device T2 are connected between the input voltage Vin and the reference ground. The first end of the inductor Lx is connected to the middle node of the first switch device T1 and the second switch device T2, and the second end is connected to the first end of the output capacitor Cout. The second end of the output capacitor Cout is grounded. Each phase power conversion circuit 101-10N receives a first switch control signal GH1-GHn provided by the control circuit 200, and receives a second switch control signal GL1-GLn provided by the control circuit 200, and controls the conduction and shutdown of the corresponding switch device according to the received first switch control signal and the second switch control signal, charges the energy storage element of the current phase for a corresponding period of time to generate the output voltage of the current phase, and the output voltage of the multi-phase power conversion circuit is combined into an output voltage Vout, and drives the load based on the output capacitor Cout.

[0051] It should be noted that although each phase power conversion circuit can refer to Figure 1 The structure of the power conversion circuit 101 in the embodiment can be understood. In this embodiment, each phase inductor corresponding to each phase power conversion circuit in the N-phase power conversion circuit 101-10N can be discrete or mutually coupled (for example, the first phase inductor is coupled with the second phase inductor; the third phase inductor is coupled with the fourth phase inductor, and so on). At the same time, although the power conversion circuit is described as having a buck topology layout (Buck), the technical solution of the present invention can be adopted for any type of layout design, such as boost, flyback, buck-boost, Cuk, Sepic and Zeta.

[0052] like Figure 1 As shown, phase current sampling signals CS1-CSn are obtained inside the N-phase power conversion circuit 101-10N, wherein the phase current sampling signals CS1-CSn represent the inductor currents in the 1st to Nth phase power conversion circuits respectively. At the common output terminal of the multi-phase power conversion circuit 101-10N, a feedback signal of the output voltage Vout is obtained.

[0053] The control circuit 200 calculates the number of open phases M according to the load current Iout of the multi-phase power supply 100, and selects and opens the M-phase power conversion circuit in the N-phase power conversion circuit 101-10N, where M<=N. The control circuit 200 determines whether to increase or decrease the phase according to the change of the number of open phases M. When increasing the phase, the control circuit 200 generates a first switch control signal and a second switch control signal according to the PWM signal of the selected phase power conversion circuit, thereby immediately turning on the selected phase power conversion circuit. When decreasing the phase, the control circuit 200 delays turning off the selected phase power conversion circuit when the phase current sampling signal of the selected phase power conversion circuit decreases from positive current to zero.

[0054] According to the multi-phase power supply of this embodiment, when the selected power conversion circuit is phase-reduced, the shutdown time of the selected phase power conversion circuit is delayed to the time when the phase current sampling signal decreases from the positive current to zero, so that the total inductor current of the multi-phase power conversion circuit remains unchanged before and after the phase reduction. Therefore, the multi-phase power supply can effectively reduce the inductor current oscillation that occurs when the phase is reduced, and improve the output stability of the system when the number of phases changes.

[0055] Figure 2 Show Figure 1 The schematic block diagram of the control circuit in the multi-phase power supply is shown. The multi-phase power supply control circuit 200 is used to generate a plurality of first switch control signals GH1-GHn and second switch control signals GL1-GLn of the N-phase power conversion circuits 101-10N.

[0056] In the figure, any phase power conversion circuit in the N-phase power conversion circuits 101-10N is taken as an example to illustrate the working principle of the control circuit 200 generating the first switch control signal GHx and the second switch control signal GLx. It can be understood that the circuit modules of all phase power conversion circuits are basically the same as the circuit modules of the example phase power conversion circuit, which will not be described in detail.

[0057] The control circuit 200 includes a PWM signal generating module 201 , a zero-crossing detecting module 202 , a first logic module 203 , and a phase enabling module 10 .

[0058] The PWM signal generating module 201 is used to generate a pulse width modulation signal PWMx of the exemplary phase power conversion circuit. The PWM signal generating module 201 receives the output voltage Vout of the multi-phase power supply 100, and compares the output voltage Vout with a voltage reference signal to generate an error signal, and adjusts the duty cycle of the pulse width modulation signal PWMx according to the error signal, thereby maintaining a stable output voltage Vout through continuous feedback adjustment. The circuit structure of the PWM signal generating module 201 is known and will not be described in detail here.

[0059] The zero-crossing detection module 202 receives the phase current sampling signal CSx of the example phase power conversion circuit. The phase current sampling signal CSx is used to characterize the inductor current ILx of the example phase power conversion circuit. The zero-crossing detection module 202 compares the phase current sampling signal CSx with the current reference signal to obtain the zero-crossing detection signal ZCDx. A predetermined value of the current reference signal close to zero can be selected. When the phase current sampling signal CSx is greater than the reference current, the zero-crossing detection signal ZCDx is in an invalid state (e.g., a low level) to indicate the positive current stage of the phase current sampling signal CSx. When the phase current sampling signal CSx is less than the reference current, the zero-crossing detection signal ZCDx is in a valid state (e.g., a high level) to indicate the negative current stage of the phase current sampling signal CSx. When the phase current sampling signal CSx decreases from a positive current to zero, the zero-crossing detection signal ZCDx flips from an invalid state to a valid state. When the phase current sampling signal CSx crosses zero from a negative current to a positive current, the zero-crossing detection signal ZCDx flips from a valid state to an invalid state. The function of the zero-crossing detection module 202 in the existing multi-phase power supply is, for example, to synchronize the switching actions of the switching devices in the example phase power conversion circuit to reduce switching losses and improve efficiency. The circuit structure of the zero-crossing detection module 202 is known and will not be described in detail here.

[0060] The phase enable module 10 receives the pulse width modulation signal PWMx of the example phase power conversion circuit, the zero crossing detection signal ZCDx and the phase current sampling signal CS1-CSn of the N-phase power conversion circuit, and generates a phase enable signal ENx for controlling the on state of the example phase power conversion circuit. When the example phase power conversion circuit maintains the on state, the phase enable signal ENx maintains the valid state. When the example phase power conversion circuit maintains the off state, the phase enable signal ENx maintains the invalid state.

[0061] Further, the phase enable module 10 can determine the start-up state change of the example phase power conversion circuit. In the case of increasing the phase of the example phase power conversion circuit, the phase enable signal ENx immediately flips from the invalid state to the valid state. In the case of subtracting the phase of the example phase power conversion circuit, the phase enable signal ENx is delayed from the valid state to the invalid state according to the pulse width modulation signal PWMx and the zero crossing detection signal ZDx of the example phase power conversion circuit.

[0062] The first logic module 203 receives the pulse width modulation signal PWMx and the phase enable signal ENx of the example phase power conversion circuit. The first logic module 203 performs a logic operation on the pulse width modulation signal PWMx and the phase enable signal ENx of the example phase power conversion circuit to generate a first switch control signal GHx and a second switch control signal GLx of the example phase power conversion circuit. As shown in the figure, the first logic module 203 includes a first AND gate U1 and a second AND gate U2. The first AND gate U1 performs a logic AND operation on the pulse width modulation signal PWMx and the corresponding phase enable signal ENx to generate the first switch control signal GH. The second AND gate U2 performs a logic AND operation on the inverted signal of the pulse width modulation signal PWMx and the corresponding phase enable signal ENx to generate the second switch control signal GL. However, the present invention is not limited to this, and any logic circuit can be used to implement the same logic operation function of the first logic module 203.

[0063] Figure 3 Show Figure 2 The first example of the phase enabling module in the control circuit shown in FIG. 10 includes a phase number calculation module 11 , a phase control module 12 and a second logic module 13 .

[0064] The phase number calculation module 11 receives the phase current sampling signals CS1-CSn of the N-phase power conversion circuits 101-10N, and calculates the total inductor current ILsum of the N-phase power conversion circuits 101-10N according to the phase current sampling signals CS1-CSn, which is used to characterize the load current Iload of the multi-phase power supply 100. However, the present invention is not limited thereto, for example, the phase number calculation module 11 can directly obtain the current sampling signal of the load current Iload of the multi-phase power supply 100.

[0065] Further, the phase number calculation module 11 calculates the number of phases M to be turned on according to the load current Iload of the multi-phase power supply 100. In one example, the phase number calculation module 11 obtains the number of phases M corresponding to the load current Iload through a comparison table according to the detected load current Iload. In another example, the phase number calculation module 11 determines the number of phases M corresponding to the load current Iload by comparing the load current Iload with current thresholds of different phase numbers according to the detected load current Iload.

[0066] The phase control module 12 receives the PWM signal PWMx of the example power conversion circuit, the zero-crossing detection signal ZCDx of the example phase power conversion circuit, and the number of open phases M, and generates a phase control signal ph_enx according to the PWM signal PWMx, the zero-crossing detection signal ZCDx, and the number of open phases M to determine whether to increase or decrease the phase of the example power conversion circuit. For example, when the PWM signal PWMx of the example phase power conversion circuit changes from a valid state (e.g., a high level) to an invalid state (e.g., a low level), and the zero-crossing detection signal ZCDx of the example phase power conversion circuit is in an invalid state, the phase control signal ph_enx changes from a valid state to an invalid state.

[0067] Further, when the sequence number of the example phase power conversion circuit is greater than the initial value of the number of open phases M and less than or equal to the current value of the number of open phases M, the phase control module 12 can determine to increase the phase of the example phase power conversion circuit. When the sequence number of the example phase power conversion circuit is less than or equal to the initial value of the number of open phases M and greater than the current value of the number of open phases M, the phase control module 12 can determine to reduce the phase of the example phase power conversion circuit. However, the present invention is not limited to this. When increasing the phase, the phase control module 12 can turn on any idle phase in the N-phase power conversion circuit 101-10N, and when reducing the phase, the phase control module 12 can turn off any working phase in the N-phase power conversion circuit 101-10N.

[0068] The second logic module 13 receives the zero-crossing detection signal ZCDx and the phase control signal ph_enx of the exemplary phase power conversion circuit, and generates a phase enable signal Enx according to the zero-crossing detection signal ZCDx and the phase control signal ph_enx.

[0069] In the case where the phase control module 12 has determined to perform phase subtraction on the example phase power conversion circuit, the second logic module 13 performs a logic operation on the zero-crossing detection signal ZCDx and the phase control signal ph_enx of the example phase power conversion circuit to generate a phase enable signal Enx. As shown in the figure, the second logic module 23 includes an OR gate U3. The OR gate U3 performs a logic OR operation on the inverted signal of the zero-crossing detection signal ZCDx and the corresponding phase control signal ph_enx to generate the phase enable signal Enx. However, the present invention is not limited to this, and any logic circuit can be used to implement the same logic operation function of the second logic module 13.

[0070] Figure 4 Show Figure 2 The second example of the phase enabling module in the control circuit shown in FIG. 20 includes a phase number calculation module 11 , a zero-crossing detection shielding module 21 , a phase control module 22 and a second logic module 23 .

[0071] The phase number calculation module 11 receives the phase current sampling signals CS1-CSn of the N-phase power conversion circuits 101-10N, and calculates the total inductor current ILsum of the N-phase power conversion circuits 101-10N according to the phase current sampling signals CS1-CSn, which is used to characterize the load current Iload of the multi-phase power supply 100. However, the present invention is not limited thereto, for example, the phase number calculation module 11 can directly obtain the current sampling signal of the load current Iload of the multi-phase power supply 100.

[0072] Further, the phase number calculation module 11 calculates the number of phases M to be turned on according to the load current Iload of the multi-phase power supply 100. In one example, the phase number calculation module 11 obtains the number of phases M corresponding to the load current Iload through a comparison table according to the detected load current Iload. In another example, the phase number calculation module 11 determines the number of phases M corresponding to the load current Iload by comparing the load current Iload with current thresholds of different phase numbers according to the detected load current Iload.

[0073] The zero-crossing detection shielding module 21 receives the PWM signal PWMx of the example power conversion circuit, and is used to generate the zero-crossing detection shielding signal ZCD_blankx. The zero-crossing detection shielding signal ZCD_blankx is used to characterize the shielding time period starting from the effective phase of the PWM signal PWMx. When the effective states of the PWM signal PWMx and the zero-crossing detection shielding signal ZCD_blankx are both high, and the invalid states of the PWM signal PWMx and the zero-crossing detection shielding signal ZCD_blankx are both low, the rising edge of the zero-crossing detection shielding signal ZCD_blankx is aligned with the rising edge of the PWM signal PWMx, and the falling edge of the zero-crossing detection shielding signal ZCD_blankx is delayed by a fixed time period zcd_blank_time relative to the falling edge of the PWM signal PWMx. In this embodiment, the zero-crossing detection shielding signal ZCD_blankx generated by the zero-crossing detection shielding module 21 is used to prevent the phase control signal ph_enx signal from being set to zero, and the inductor is still in the alternating sequence charging process.

[0074] The phase control module 22 receives the number of turned-on phases M, the zero-crossing detection signal ZCDx of the exemplary phase power conversion circuit, and the zero-crossing detection mask signal ZCD_blankx.

[0075] The phase control module 22 determines whether to increase or decrease the phase of the example power conversion circuit according to the number of open phases M. When the sequence number of the example phase power conversion circuit is greater than the initial value of the number of open phases M and is less than or equal to the current value of the number of open phases M, the phase control module 22 can determine to increase the phase of the example phase power conversion circuit. When the sequence number of the example phase power conversion circuit is less than or equal to the initial value of the number of open phases M and greater than the current value of the number of open phases M, the phase control module 22 can determine to decrease the phase of the example phase power conversion circuit. However, the present invention is not limited to this. When increasing the phase, the phase control module 22 can turn on any idle phase in the N-phase power conversion circuit 101-10N, and when decreasing the phase, the phase control module 22 can turn off any working phase in the N-phase power conversion circuit 101-10N.

[0076] Further, the phase control module 22 determines whether to perform the first delay according to the zero-crossing detection signal ZCDx and the zero-crossing detection shielding signal ZCD_blankx of the example phase power conversion circuit. If the zero-crossing detection signal ZCDx is in a valid state, or the zero-crossing detection shielding signal ZCD_blankx is in a valid state, the phase control module 22 performs the first delay, wherein the trigger edge of the phase control signal ph_enx is delayed to a fixed time period zcd_blank_time after the inductor charging stage of the example phase power conversion circuit, that is, delayed to the zero-crossing detection signal ZCDx and the zero-crossing detection shielding signal ZCD_blankx are both in an invalid state. Since the power conversion circuit will have a period of noise at the moment when the high and low levels of the PWM signal change, the delay method of the embodiment of the present invention can effectively shield the noise after the inductor charging time ends, thereby improving the stability of the circuit.

[0077] The second logic module 23 receives the zero-crossing detection signal ZCDx and the phase control signal ph_enx of the exemplary phase power conversion circuit, and generates a phase enable signal Enx according to the zero-crossing detection signal ZCDx and the phase control signal ph_enx.

[0078] In the case where the phase control module 22 has determined to perform phase subtraction on the example phase power conversion circuit, the second logic module 23 performs a logic operation on the zero-crossing detection signal ZCDx and the phase control signal ph_enx of the example phase power conversion circuit to generate a phase enable signal Enx. As shown in the figure, the second logic module 23 includes an OR gate U3. The OR gate U3 performs a logic OR operation on the inverted signal of the zero-crossing detection signal ZCDx and the corresponding phase control signal ph_enx to generate the phase enable signal Enx. However, the present invention is not limited to this, and any logic circuit can be used to implement the same logic operation function of the second logic module 23.

[0079] The second logic module 23 determines whether to perform a second delay according to the zero-crossing detection signal ZCDx of the example phase power conversion circuit. If the zero-crossing detection signal ZCDx is in an invalid state, the second logic module 23 performs a second delay, wherein the trigger edge of the phase control signal ph_enx is delayed to the moment when the inductor current of the example phase power conversion circuit decreases from a positive current to zero, as the phase enable signal ENx. If the zero-crossing detection signal ZCDx is in a valid state, the second logic module 23 directly outputs the phase control signal ph_enx as the phase enable signal ENx.

[0080] Figure 5The working waveform diagram of the multi-phase power supply control circuit 20 according to the embodiment of the present invention is shown. The initial opening phase number M of the multi-phase power supply control circuit 20 is 7, and the serial number of the exemplary power conversion circuit is 7. Since the serial number of the 7th phase power conversion circuit is less than or equal to the opening phase number M=7, the initial state of the exemplary power conversion circuit is the opening state.

[0081] At time t0, since the load current Iload decreases below the current threshold, the phase number calculation module 11 in the control circuit 20 calculates the number of open phases M=6 according to the load current Iload. Since the sequence number of the 7th phase power conversion circuit is greater than the number of open phases M=6, the phase control module 22 in the control circuit 20 determines to reduce the phase of the 7th phase power conversion circuit according to the number of open phases M=6.

[0082] Further, the phase control module 22 in the control circuit 20 determines whether to perform the first delay according to the zero crossing detection signal ZCD7 and the zero crossing detection shielding signal ZCD_blank7 of the 7th phase power conversion circuit. At this time, since the zero crossing detection signal ZCD7 is in a valid state, indicating that the phase current sampling signal of the 7th phase power conversion circuit is in a negative current period, the phase control module 22 starts the first delay from time t0.

[0083] At time t1, the zero-crossing detection signal ZCD7 of the 7th phase power conversion circuit is in an invalid state, and the zero-crossing detection shielding signal ZCD_blank7 is flipped from a valid state to an invalid state. At this time, the phase control module 22 in the control circuit 20 flips the phase control signal ph_en7 from a valid state to an invalid state, and the first delay ends.

[0084] After the phase control module 22 performs the first delay, the triggering edge of the phase control signal ph_en7 has been delayed to a fixed time period zcd_blank_time after the inductor charging phase of the seventh-phase power conversion circuit.

[0085] Further, the second logic module 23 in the control circuit 20 determines whether to perform a second delay according to the zero-crossing detection signal ZCD7 of the seventh-phase power conversion circuit. At this time, since the zero-crossing detection signal ZCD7 is in an invalid state, it indicates that the phase current sampling signal of the seventh-phase power conversion circuit is a positive current and has not yet decreased to zero. Therefore, the second logic module 23 performs a second delay starting from time t1.

[0086] At time t2, the zero-crossing detection signal ZCD7 of the 7th phase power conversion circuit flips from the invalid state to the valid state. At this time, the second logic module 23 delays the trigger edge of the phase control signal ph_en7 to time t2 to obtain the trigger edge of the phase enable signal EN7. The phase enable signal EN7 of the 7th phase power conversion circuit flips from the valid state to the invalid state, and the second delay ends.

[0087] After the second logic module 23 performs the second delay, the trigger edge of the enable signal EN7 is delayed relative to the trigger edge of the phase control signal ph_en7 to the moment when the phase current sampling signal of the seventh phase power conversion circuit decreases from positive current to zero.

[0088] Therefore, the shutdown time of the 7th phase power conversion circuit is t2, which has been delayed to the time when the phase current sampling signal of the 7th phase power conversion circuit decreases from positive current to zero after the first delay and the second delay relative to the time t1.

[0089] Figure 6 A total inductor current waveform diagram of a multi-phase power conversion circuit in a multi-phase power supply according to an embodiment of the present invention is shown.

[0090] In a multi-phase power supply, the multi-phase power converter is initially turned on with the number of phases M=2.

[0091] At time t0 , since the load current Iload decreases below the current threshold, the phase number calculation module 11 in the control circuit 20 calculates the open phase number M=1 according to the load current Iload.

[0092] At time t2, the phase enable signal EN2 of the second phase power conversion circuit flips from a valid state to an invalid state, thereby delaying the shutdown of the second phase power conversion circuit. It can be seen that the first switching device and the second switching device in the second phase power conversion circuit are both turned off after the second phase power conversion circuit waits for a complete turn-on cycle, thereby shutting down the second phase power conversion circuit.

[0093] Figure 6 The example is a case where the load current decrease triggers the phase number to decrease, and the phase current sampling signal of the second phase power conversion circuit is in a negative current period. In this case, the control process of the control circuit includes the following stages in sequence:

[0094] (1) When the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the second phase power conversion circuit is in a negative current period, the first switching device in the second phase power conversion circuit is in an off state and the second switching device is in an on state;

[0095] (2) The PWM signal of the second phase changes from an invalid state to an effective state, and the inductor of the second phase power conversion circuit begins to charge. During the period when the PWM signal of the second phase is in the effective state, the first switch device in the second phase power conversion circuit is in the on state and the second switch device is in the off state, and the phase current sampling signal of the second phase changes from a negative current to a positive current;

[0096] (3) The PWM signal of the second phase changes from an effective state to an ineffective state. The phase control signal of the second phase changes to an ineffective state at the falling edge of the PWM signal of the second phase and when the phase current sampling signal of the second phase is a positive current, or the control signal of the second phase changes to an ineffective state after the falling edge of the PWM signal of the second phase arrives after the masking time is delayed and when the phase current sampling signal of the second phase is a positive current. During the period when the PWM signal of the second phase is in the ineffective state, the first switching device in the second phase power conversion circuit is in the off state and the second switching device is in the on state, and the phase current sampling signal of the second phase decreases from a positive current to zero.

[0097] (4) When the phase control signal of the second phase is in an invalid state and the phase current sampling signal of the second phase decreases from positive current to zero, the phase enable signal of the second phase controls the first switching device and the second switching device in the second phase power conversion circuit to be turned off, and the second phase power conversion circuit is turned off.

[0098] The above control process does not limit the present invention. There is also a situation where the load current decreases, triggering a decrease in the number of phases, and the phase current sampling signal of the second phase power conversion circuit is in a positive current period. The control process in this case is different from the above control process, but it is also when the phase control signal is invalid and the phase current sampling signal of the second phase decreases from positive current to zero, the phase enable signal of the second phase controls the first switching device and the second switching device in the second phase power conversion circuit to be turned off, thereby realizing delayed shutdown of the second phase power conversion circuit. The difference is that the second phase power conversion circuit does not need to wait for a complete opening cycle, but only needs to wait for the time for the phase current sampling signal of the second phase to decrease from positive current to zero.

[0099] The total inductor current ILsum of the multiphase power conversion circuit of the multiphase power supply remains unchanged before and after the second-phase power conversion circuit is turned off. Therefore, the multiphase power supply can effectively reduce the total inductor current overshoot or oscillation occurring when the phase is reduced, and improve the output stability of the system when the number of phases changes.

[0100] Figure 7 FIG. 1 is a flow chart showing a multi-phase power supply control method according to an embodiment of the present invention. Figure 2 The control circuit shown executes at least some steps of the multi-phase power supply control method.

[0101] In step S01, the number of open phases M is calculated according to the load current of the multi-phase power supply.

[0102] In step S02, it is determined whether to perform phase reduction on the selected phase power conversion circuit according to the number of turned-on phases M.

[0103] For example, when the sequence number of the selected phase power conversion circuit is greater than the initial value of the number of open phases M and less than or equal to the current value of the number of open phases M, it can be determined that the selected phase power conversion circuit is phase-increased. When the sequence number of the selected phase power conversion circuit is less than or equal to the initial value of the number of open phases M and greater than the current value of the number of open phases M, it can be determined that the selected phase power conversion circuit is phase-reduced.

[0104] In the case of performing phase subtraction on the selected phase power conversion circuit, steps S03 to S07 are performed to delay the shutdown time of the selected phase power conversion circuit to the time when the phase current sampling signal of the selected phase power conversion circuit decreases from positive current to zero.

[0105] In step S03 , the zero-crossing detection signal ZCDx and the zero-crossing detection masking signal ZCD_blankx of the selected phase power conversion circuit are acquired.

[0106] For example, the phase current sampling signal CSx of the selected phase power conversion circuit is compared with the current reference signal to obtain the zero-crossing detection signal ZCDx. A predetermined value of the current reference signal close to zero can be selected. When the phase current sampling signal CSx is greater than the reference current, the zero-crossing detection signal ZCDx is in an invalid state, which is used to indicate the positive current stage of the phase current sampling signal CSx. When the phase current sampling signal CSx is less than the reference current, the zero-crossing detection signal ZCDx is in a valid state, which is used to indicate the negative current stage of the phase current sampling signal CSx. When the phase current sampling signal CSx decreases from a positive current to zero, the zero-crossing detection signal ZCDx flips from an invalid state to a valid state. When the phase current sampling signal CSx crosses zero from a negative current to a positive current, the zero-crossing detection signal ZCDx flips from a valid state to an invalid state.

[0107] For example, the PWM signal PWMx of the selected phase power conversion circuit is used as a trigger signal to obtain the zero-crossing detection shielding signal ZCD_blankx. The zero-crossing detection shielding signal ZCD_blankx is used to characterize the shielding time period of the PWM signal PWMx starting from its rising edge. When the valid states of the PWM signal PWMx and the zero-crossing detection shielding signal ZCD_blankx are both high level, and the invalid states of the PWM signal PWMx and the zero-crossing detection shielding signal ZCD_blankx are both low level, the rising edge of the zero-crossing detection shielding signal ZCD_blankx is aligned with the rising edge of the PWM signal PWMx, and the falling edge is delayed by a fixed time period zcd_blank_time relative to the falling edge of the PWM signal PWMx.

[0108] In step S04, it is determined whether the zero-crossing detection signal ZCDx and the zero-crossing detection shielding signal ZCD_blankx of the selected phase power conversion circuit are both invalid. If yes, step S05 is executed. If not, the process returns to step S03.

[0109] The loop of steps S03 and S04 is used to perform the first delay, delaying the trigger edge of the phase control signal ph_enx to a fixed time period zcd_blank_time after the inductor charging phase of the exemplary phase power conversion circuit.

[0110] In step S05 , the zero-crossing detection signal ZCDx of the selected phase power conversion circuit is reacquired.

[0111] In step S06, it is determined whether the zero-crossing detection signal ZCDx of the selected phase power conversion circuit is valid. If yes, step S07 is executed. If not, the process returns to step S05.

[0112] The loop of steps S05 and S06 is used to perform a second delay, delaying the trigger edge of the phase control signal ph_enx to the moment when the phase current sampling signal of the exemplary phase power conversion circuit decreases from positive current to zero, as the phase enable signal ENx.

[0113] In step S07 , the phase enable signal Enx of the selected phase power conversion circuit is flipped from the valid state to the invalid state, thereby shutting down the selected phase power conversion circuit.

[0114] In summary, in the multi-phase power supply and its control circuit and control method provided in the embodiment of the present invention, when the phase reduction operation is performed on the selected phase power conversion circuit in the multi-phase power supply, if the phase current sampling signal of the corresponding phase power conversion circuit is in the negative current period when the number of phases is reduced, the shutdown time of the selected phase power conversion circuit is delayed until the phase current sampling signal of the corresponding phase power conversion circuit becomes a positive current and decreases to zero. Similarly, if the phase current sampling signal of the corresponding phase power conversion circuit is in the positive current period when the number of phases is reduced, the shutdown time of the selected phase power conversion circuit is delayed until the current decreases from the positive current to zero. Compared with the solution of the conventional technology of immediately shutting down the corresponding phase power conversion circuit when the phase is reduced, the multi-phase power supply and its control circuit and control method provided in the embodiment of the invention can effectively reduce the inductor current oscillation occurring during the phase reduction operation, avoid the overshoot of the output voltage, and improve the stability of the circuit output.

[0115] In the above description, the well-known structural elements and steps are not described in detail. However, it should be understood by those skilled in the art that the corresponding structural elements and steps can be realized by various technical means. In addition, in order to form the same structural elements, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although each embodiment is described above respectively, this does not mean that the measures in each embodiment cannot be advantageously used in combination.

[0116] According to the embodiments of the present invention, as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A control circuit for a multi-phase power supply, wherein: The multi-phase power supply includes a multi-phase power conversion circuit, the control circuit includes a plurality of phase control circuits, each phase control circuit controls a corresponding phase power conversion circuit, and each phase control circuit includes: A PWM signal generating module, which generates a PWM signal of the corresponding phase power conversion circuit according to the output voltage of the multi-phase power supply; A zero-crossing detection module, which generates a zero-crossing detection signal of the corresponding phase power conversion circuit according to the phase current sampling signal of the corresponding phase power conversion circuit; a phase enable module, generating a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal; and a first logic module, generating a switch control signal of the corresponding phase power conversion circuit according to the PWM signal and the phase enable signal, The phase enable module calculates the number of phases to be turned on according to the multi-phase current sampling signal, and when the number of phases of the multi-phase power conversion circuit decreases, the phase enable module delays shutting down the corresponding phase power conversion circuit according to the corresponding phase enable signal when the phase current sampling signal of the corresponding phase power conversion circuit decreases from positive current to zero, thereby realizing phase reduction control of the multi-phase power conversion circuit.

2. The control circuit according to claim 1, wherein: The phase enabling module comprises: A phase number calculation module, which calculates the number of phases to be turned on according to the multi-phase current sampling signal; a phase control module, generating a phase control signal of a corresponding phase according to the phase number, the zero-crossing detection signal of the corresponding phase, and the PWM signal of the corresponding phase; and The second logic module generates the phase enable signal of the corresponding phase according to the phase control signal of the corresponding phase and the zero-crossing detection signal of the corresponding phase, and the phase enable signal turns on or off the power conversion circuit of the corresponding phase.

3. The control circuit according to claim 2, wherein: When the PWM signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state. When the phase control signal is in an invalid state, the first switching device controlled by the corresponding phase power conversion circuit is kept turned off.

4. The control circuit according to claim 2, wherein: The total inductor current of the multi-phase power conversion circuit is calculated according to the multi-phase current sampling signal, and the total inductor current represents the load current of the multi-phase power supply. When the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control circuit includes the following stages in sequence: (1) The load current decreases and triggers the phase number to decrease, the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state; (2) The corresponding PWM signal changes from an invalid state to an effective state, and the inductor of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in the effective state, the first switch device in the corresponding phase power conversion circuit is in the on state and the second switch device is in the off state, and the corresponding phase current sampling signal changes from a negative current to a positive current; (3) The corresponding PWM signal changes from a valid state to an invalid state. At the falling edge of the corresponding PWM signal and when the corresponding phase current sampling signal is a positive current, the corresponding phase control signal changes to an invalid state. During the period when the corresponding PWM signal is in the invalid state, the first switch device in the corresponding phase power conversion circuit is in the off state and the second switch device is in the on state, and the corresponding phase current sampling signal decreases from a positive current to zero. (4) When the corresponding phase control signal is in an invalid state and the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switching device and the second switching device in the corresponding phase power conversion circuit to be turned off, and the corresponding phase power conversion circuit is turned off.

5. The control circuit according to claim 1, wherein: The phase enabling module comprises: A phase number calculation module, which calculates the number of phases to be turned on according to the multi-phase current sampling signal; A zero-crossing shielding module generates a zero-crossing detection shielding signal of a corresponding phase according to the PWM signal of the corresponding phase; A phase control module generates a phase control signal of a corresponding phase according to the phase number, the zero-crossing detection signal of the corresponding phase, and the zero-crossing detection shielding signal of the corresponding phase; and The second logic module generates the phase enable signal of the corresponding phase according to the phase control signal of the corresponding phase and the zero-crossing detection signal of the corresponding phase, and the phase enable signal turns on or off the power conversion circuit of the corresponding phase.

6. The control circuit according to claim 5, wherein: When the rising edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from an invalid state to a valid state; When the falling edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from a valid state to an invalid state after a delay shielding time; When the zero-crossing detection shielding signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state. When the phase control signal is in an invalid state, the first switching device in the corresponding phase power conversion circuit is kept turned off.

7. The control circuit according to claim 5, wherein: The masking time period of the zero-crossing masking module is greater than the pulse width of the effective state of the PWM signal.

8. The control circuit according to claim 5, wherein: The phase control module is used to perform a logic operation on the zero-crossing detection signal of the corresponding phase, the zero-crossing detection shielding signal of the corresponding phase, and the phase number to obtain the phase control signal of the corresponding phase.

9. The control circuit according to claim 8, wherein: When the zero-crossing detection signal of the corresponding phase power conversion circuit is invalid and the zero-crossing detection shielding signal is invalid, the phase control signal of the corresponding phase power conversion circuit is flipped from a valid state to an invalid state.

10. The control circuit according to claim 6, wherein: The total inductor current of the multi-phase power conversion circuit is calculated according to the multi-phase current sampling signal, and the total inductor current represents the load current of the multi-phase power supply. When the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control circuit includes the following stages in sequence: (1) when the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the first switching device in the corresponding phase power conversion circuit is in an off state and the second switching device is in an on state; (2) The corresponding PWM signal changes from an invalid state to an effective state, and the inductor of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in the effective state, the first switch device in the corresponding phase power conversion circuit is in the on state and the second switch device is in the off state, and the corresponding phase current sampling signal changes from a negative current to a positive current; (3) The corresponding PWM signal changes from a valid state to an invalid state. When the falling edge of the corresponding PWM signal arrives, the corresponding phase control signal changes to an invalid state after the masking time is delayed and the corresponding phase current sampling signal is a positive current. During the period when the corresponding PWM signal is in the invalid state, the first switching device in the corresponding phase power conversion circuit is in the off state and the second switching device is in the on state, and the corresponding phase current sampling signal decreases from a positive current to zero. (4) When the corresponding phase control signal is in an invalid state and the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switching device and the second switching device in the corresponding phase power conversion circuit to be turned off, and the corresponding phase power conversion circuit is turned off.

11. The control circuit according to claim 2 or 5, wherein: The second logic module includes an OR gate, which is used to perform a logic OR operation on the phase control signal and the inverted signal of the zero-crossing detection signal.

12. The control circuit according to claim 1, wherein: The first logic module includes: A first AND gate, configured to perform a logic AND operation on the PWM signal of the corresponding phase and a corresponding phase enable signal to generate a plurality of first switch control signals; and A second AND gate is used to perform a logic AND operation on the inverted signal of the PWM signal of the corresponding phase and the corresponding phase enable signal to generate a plurality of second switch control signals, The corresponding phase power conversion circuits receive corresponding first switch control signals and corresponding second switch control signals respectively.

13. The control circuit according to claim 1, wherein: The zero-crossing detection module is used to compare the phase current sampling signal of the corresponding phase power conversion circuit with the current reference signal to obtain the zero-crossing detection signal.

14. The control circuit according to claim 1, wherein: The PWM signal generating module is used for comparing the output voltage with a voltage reference signal to generate an error signal, and adjusting the duty cycle of the PWM signal according to the error signal.

15. The control circuit according to claim 1, wherein: Phase subtraction is performed according to the sequence number of the multi-phase power conversion circuit.

16. A multiphase power supply comprising: The control circuit according to any one of claims 1 to 15, used to generate a plurality of switch control signals; as well as A multi-phase power conversion circuit comprises a plurality of switch circuits, wherein the plurality of switch circuits receive corresponding switch control signals, and output ends of the plurality of switch circuits are coupled together to supply power to a load.

17. A control method for a multi-phase power supply, the multi-phase power supply comprising a multi-phase power conversion circuit, the control method comprising: Generate a PWM signal of a corresponding phase power conversion circuit according to the output voltage of the multi-phase power supply; Generate a zero-crossing detection signal of the corresponding phase power conversion circuit according to the phase current sampling signal of the corresponding phase power conversion circuit; Generate a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal; as well as generating a switch control signal of the corresponding phase power conversion circuit according to the PWM signal and the phase enable signal, Wherein, the control method further includes: The number of phases to be turned on is calculated according to the multi-phase current sampling signal, and when the number of phases of the multi-phase power conversion circuit is reduced, the phase enable module delays shutting down the corresponding phase power conversion circuit according to the corresponding phase enable signal when the phase current sampling signal of the corresponding phase power conversion circuit decreases from positive current to zero, thereby realizing phase reduction control of the multi-phase power conversion circuit.

18. The control method according to claim 17, wherein: Generating a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal comprises: Calculating the number of phases to be turned on according to the multi-phase current sampling signal; generating a phase control signal of the corresponding phase according to the phase number, the zero-crossing detection signal of the corresponding phase, and the PWM signal of the corresponding phase; and A logic OR operation is performed on the phase control signal of the corresponding phase and the inverted signal of the zero-crossing detection signal of the corresponding phase to generate the phase enable signal of the corresponding phase, and the phase enable signal turns on or off the power conversion circuit of the corresponding phase.

19. The control method according to claim 18, wherein: When the PWM signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state. When the phase control signal is in an invalid state, the first switching device of the corresponding phase power conversion circuit is kept turned off.

20. The control method according to claim 18, wherein: It also includes: calculating the total inductance current of the multi-phase power conversion circuit according to the multi-phase current sampling signal, the total inductance current represents the load current of the multi-phase power supply, when the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control method includes the following stages in sequence: (1) The load current decreases and triggers the phase number to decrease, the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the first switch device in the corresponding phase power conversion circuit is in an off state and the second switch device is in an on state; (2) The corresponding PWM signal changes from an invalid state to an effective state, and the inductor of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in the effective state, the first switch device in the corresponding phase power conversion circuit is in the on state and the second switch device is in the off state, and the corresponding phase current sampling signal changes from a negative current to a positive current; (3) The corresponding PWM signal changes from a valid state to an invalid state. At the falling edge of the corresponding PWM signal and when the corresponding phase current sampling signal is a positive current, the corresponding phase control signal changes to an invalid state. During the period when the corresponding PWM signal is in the invalid state, the first switch device in the corresponding phase power conversion circuit is in the off state and the second switch device is in the on state, and the corresponding phase current sampling signal decreases from a positive current to zero. (4) When the corresponding phase control signal is in an invalid state and the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switching device and the second switching device in the corresponding phase power conversion circuit to be turned off, and the corresponding phase power conversion circuit is turned off.

21. The control method according to claim 17, wherein: Generating a phase enable signal according to the PWM signal, the zero-crossing detection signal and the multi-phase current sampling signal comprises: Calculating the number of phases to be turned on according to the multi-phase current sampling signal; Generating a zero-crossing detection shielding signal of a corresponding phase according to the PWM signal of the corresponding phase; generating a phase control signal of a corresponding phase according to the phase number, the zero-crossing detection signal of the corresponding phase, and the zero-crossing detection shielding signal of the corresponding phase; and A logic OR operation is performed on the phase control signal of the corresponding phase and the inverted signal of the zero-crossing detection signal of the corresponding phase to generate the phase enable signal of the corresponding phase, and the phase enable signal turns on or off the power conversion circuit of the corresponding phase.

22. The control method according to claim 21, wherein: When the rising edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from an invalid state to a valid state; When the falling edge of the PWM signal of the corresponding phase arrives, the zero-crossing detection shielding signal of the corresponding phase is flipped from a valid state to an invalid state after a delay shielding time; When the zero-crossing detection shielding signal of the corresponding phase changes from a valid state to an invalid state, and the zero-crossing detection signal of the corresponding phase is in an invalid state, the phase control signal of the corresponding phase changes from a valid state to an invalid state. When the phase control signal is in an invalid state, the first switching device in the corresponding phase power conversion circuit is kept turned off.

23. The control method according to claim 22, wherein: The masking time is greater than a pulse width of an active state of the plurality of PWM signals.

24. The control method according to claim 21, wherein: When the zero-crossing detection signal of the corresponding phase power conversion circuit is invalid and the zero-crossing detection shielding signal is invalid, the phase control signal of the corresponding phase power conversion circuit is flipped from a valid state to an invalid state.

25. The control method according to claim 23, wherein: It also includes: calculating the total inductance current of the multi-phase power conversion circuit according to the multi-phase current sampling signal, the total inductance current represents the load current of the multi-phase power supply, when the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the control process of the control method includes the following stages in sequence: (1) when the load current decreases and triggers the phase number to decrease, and the phase current sampling signal of the corresponding phase power conversion circuit is in a negative current period, the first switching device in the corresponding phase power conversion circuit is in an off state and the second switching device is in an on state; (2) The corresponding PWM signal changes from an invalid state to an effective state, and the inductor of the corresponding phase power conversion circuit starts to charge. During the period when the corresponding PWM signal is in the effective state, the first switch device in the corresponding phase power conversion circuit is in the on state and the second switch device is in the off state, and the corresponding phase current sampling signal changes from a negative current to a positive current; (3) The corresponding PWM signal changes from a valid state to an invalid state. When the falling edge of the corresponding PWM signal arrives, the corresponding phase control signal changes to an invalid state after the masking time is delayed and the corresponding phase current sampling signal is a positive current. During the period when the corresponding PWM signal is in the invalid state, the first switching device in the corresponding phase power conversion circuit is in the off state and the second switching device is in the on state, and the corresponding phase current sampling signal decreases from a positive current to zero. (4) When the corresponding phase control signal is in an invalid state and the phase current sampling signal decreases from positive current to zero, the phase enable signal of the corresponding phase controls the first switching device and the second switching device in the corresponding phase power conversion circuit to be turned off, and the corresponding phase power conversion circuit is turned off.

26. The control method according to claim 17, wherein: The step of generating a switch control signal of the corresponding phase power conversion circuit according to the PWM signal and the phase enable signal comprises: Performing a logic AND operation on the PWM signal of the corresponding phase and the corresponding phase enable signal to generate a plurality of first switch control signals; and Performing a logic AND operation on the inverted signal of the PWM signal of the corresponding phase and the corresponding phase enable signal to generate a plurality of second switch control signals, The corresponding phase power conversion circuits receive corresponding first switch control signals and corresponding second switch control signals respectively.

27. The control method according to claim 17, wherein: The step of generating a zero-crossing detection signal of the corresponding phase power conversion circuit according to the phase current sampling signal of the corresponding phase power conversion circuit comprises: The phase current sampling signal of the corresponding phase power conversion circuit is compared with the current reference signal to obtain the zero-crossing detection signal.

28. The control method according to claim 17, wherein: The step of generating a PWM signal of a corresponding phase power conversion circuit according to the output voltage of the multi-phase power supply comprises: The output voltage is compared with a voltage reference signal to generate an error signal, and the duty cycle of the PWM signal is adjusted according to the error signal.

29. The control method according to claim 17, wherein: Phase subtraction is performed according to the sequence number of the multi-phase power conversion circuit.

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