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 plurality of transformers, each transformer including a primary winding and a secondary winding, the secondary windings of the plurality of transformers and a compensation inductor being connected in series. The control circuit comprises a controller, an average current sampling circuit and a sampling correction circuit. The controller provides a plurality of pulse width modulation signals according to an output voltage of the multi-phase power supply and a signal between a first current sampling end and a second current sampling end of the multi-phase power supply. An average current sampling circuit is connected to both ends of the primary winding of each transformer to sample an average current flowing through the plurality of switching circuits. The sampling correction circuit comprises a correction capacitor, the first end of the correction capacitor is connected to the first end of the compensation inductor, the second end of the correction capacitor is connected to the second current sampling end, and the sampling correction circuit responds to the transient change of the output current and corrects the sampling result of the average current sampling circuit according to the current flowing through the compensation inductor. The average current flowing through a plurality of switching circuits can be accurately reflected.

Description

Technical Field

[0001] Embodiments of the present invention relate to an electronic circuit, and more particularly, to a multi-phase power supply and a control circuit and a control method thereof. Background Art

[0002] A trans-inductor voltage regulator (TLVR) is a voltage regulator that uses the primary winding of a transformer as the output inductor. In a multi-phase trans-inductor voltage regulator, all corresponding transformer secondary windings are coupled in series to a reference ground. Due to the series coupling of these secondary windings, changes in load current can affect each phase circuit, so that a multi-phase trans-inductor voltage regulator can achieve faster transient response compared to other regulator topologies.

[0003] A conductive inductor regulator can use a constant on-time current mode control to generate and stabilize the output voltage. Current mode control uses a sampled current to indicate the current flowing through the output inductor as part of a constant on-time current control loop. A multiphase conductive inductor regulator can use a sampled current for each phase, or an average sampled current for all phases. The sampled current can be obtained by using a sample resistor, using the DC resistance (DCR) of the output inductor, or by other means to sense the current flowing through the output inductor. Summary of the invention

[0004] The invention provides a multi-phase power supply, a control circuit and a control method thereof.

[0005] According to an embodiment of the present invention, a control circuit for a multi-phase power supply is provided, wherein the multi-phase power supply includes a plurality of transformers, wherein each transformer includes a primary winding and a secondary winding, and the secondary windings of the plurality of transformers are connected in series with a compensation inductor, and the control circuit includes: a controller including a first current sampling terminal, a second current sampling terminal, and a plurality of switch control terminals, wherein the controller provides a plurality of pulse width modulation signals at its plurality of switch control terminals according to an output voltage of the multi-phase power supply and a signal between the first current sampling terminal and the second current sampling terminal, so as to respectively control a plurality of switch circuits of the multi-phase power supply; an average current sampling circuit connected to both ends of the primary winding of each transformer to sample an average current flowing through the plurality of switch circuits, wherein the current sampling circuit includes an average sampling capacitor, wherein a first end of the average sampling capacitor is connected to the first current sampling terminal, and a second end of the average sampling capacitor is connected to the second current sampling terminal; and a sampling correction circuit connected to the compensation inductor, wherein the sampling correction circuit includes a correction capacitor, wherein a first end of the correction capacitor is connected to a first end of the compensation inductor, and a second end of the correction capacitor is connected to the second current sampling terminal, and the sampling correction circuit injects information obtained from the compensation inductor into the second current sampling terminal in response to a transient change in the output current of the multi-phase power supply.

[0006] According to another embodiment of the present invention, a multi-phase power supply is proposed, comprising: an input end for receiving an input voltage and an output end for providing an output voltage; a plurality of transformers, each transformer comprising a primary winding and a secondary winding, the secondary windings of the plurality of transformers and a compensation inductor being connected in series; a plurality of switching circuits connected in parallel between the input end and the output end of the multi-phase power supply, each switching circuit being coupled to the output end of the multi-phase power supply through the primary winding of the corresponding transformer; and the control circuit as described above.

[0007] According to another embodiment of the present invention, a control method for a multi-phase power supply is proposed, wherein the multi-phase power supply includes a plurality of transformers, wherein each transformer includes a primary winding and a secondary winding, and the secondary windings of the plurality of transformers are connected in series with a compensation inductor, and the control method includes: sampling an average current flowing through a plurality of switch circuits of the multi-phase power supply through an average current sampling circuit; in response to transient changes in the output current of the multi-phase power supply, correcting the sampling result of the average current sampling circuit through a sampling correction circuit according to the current flowing through the compensation inductor; generating a total current sampling signal according to the sampling result of the corrected average current sampling circuit; and generating a plurality of pulse width modulation signals according to the output voltage and the total current sampling signal to control the plurality of switch circuits of the multi-phase power supply.

[0008] The multi-phase power supply and its control circuit and control method respond to transient changes in the output current and correct the sampling result of the average current sampling circuit according to the current flowing through the compensation inductor, so as to accurately reflect the average current flowing through multiple switch circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to better understand the present invention, the present invention will be described in detail with reference to the following drawings, wherein the same elements have the same reference numerals.

[0010] Figure 1 A circuit structure schematic diagram of a power stage circuit 100 for a multi-phase power supply according to an embodiment of the present invention is shown;

[0011] Figure 2 A schematic diagram of the circuit structure of a multi-phase power supply 200 according to an embodiment of the present invention is shown;

[0012] Figure 3 shows a circuit schematic diagram of a control circuit 201A according to an embodiment of the present invention;

[0013] Figure 4 shows a circuit schematic diagram of a control circuit 201B according to an embodiment of the present invention;

[0014] Figure 5 A circuit diagram of an existing current sampling circuit 500 is shown;

[0015] Figure 6 shows a waveform diagram of a total current sampling signal Is_total and an output current Io obtained according to an existing current sampling circuit 500;

[0016] Figure 7 The embodiment of the present invention is shown Figure 2 The waveform diagram of the total current sampling signal Is_total and the output current Io obtained by the multi-phase power supply 200 shown;

[0017] Figure 8 A schematic diagram of the circuit structure of a multi-phase power supply 800 according to an embodiment of the present invention is shown;

[0018] Fig. 9 A circuit structure schematic diagram 900 of multiple phase current sampling circuits according to an embodiment of the present invention is shown;

[0019] Fig.10 shows a circuit structure diagram of a controller 300B according to an embodiment of the present invention;

[0020] Fig.11 A control method 1100 of a multi-phase power supply according to an embodiment of the present invention is shown;

[0021] Fig.12 A control method 1200 of a multi-phase power supply according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0022] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not have to be used to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, materials or methods are not specifically described.

[0023] Figure 1 FIG. 1 is a schematic diagram of a circuit structure of a power stage circuit 100 for a multi-phase power supply according to an embodiment of the present invention. The power stage circuit 100 includes a conductive inductor regulator, that is, Figure 1 The power stage circuit 100 includes an input terminal for receiving an input voltage VIN, an output terminal for providing an output voltage VOUT, a plurality of transformers T1 to Tn, a plurality of switch circuits 120 (i.e., 120-1 to 120-n) connected in parallel between the input voltage VIN and the output voltage VOUT, and a compensation inductor Lc. Where n is a natural number greater than 1. The power stage circuit 100 provides an output voltage VOUT and an output current Io to a load (not shown). Each switch circuit 120 generates one of the phases of the power stage circuit 100. Figure 1 In the illustrated embodiment, the switch circuit 120-1 generates the first phase of the power stage circuit 100, the switch circuit 120-2 generates the second phase of the power stage circuit 100, and so on, the switch circuit 120-n generates the nth phase of the power stage circuit 100. Each switch circuit 120 includes at least one switch controlled by a corresponding pulse width modulation signal PWM, for example, the pulse width modulation signal PWM1 controls the on and off of the switch in the switch circuit 120-1, the pulse width modulation signal PWM2 controls the on and off of the switch in the switch circuit 120-2, and the pulse width modulation signal PWMn controls the on and off of the switch in the switch circuit 120-n.

[0024] exist Figure 1In the illustrated embodiment, each switch circuit 120 includes a high-side switch M1 and a low-side switch M2. The first end of the high-side switch M1 is connected to the input voltage VIN, the second end of the high-side switch M1 is connected to the first end of the low-side switch M2 to form a switch node, and the second end of the low-side switch M2 is connected to the reference ground GND. For example, the second end of the high-side switch M1 in the switch circuit 120-1 is connected to the first end of the low-side switch M2 to form a switch node SW1, the second end of the high-side switch M1 in the switch circuit 120-2 is connected to the first end of the low-side switch M2 to form a switch node SW2, and the second end of the high-side switch M1 in the switch circuit 120-n is connected to the first end of the low-side switch M2 to form a switch node SWn. The control ends of the high-side switch M1 and the low-side switch M2 are connected to the corresponding pulse width modulation signal PWM. For example, the high-side switch M1 and the low-side switch M2 of the switch circuit 120-1 are turned on and off under the control of the pulse width modulation signal PWM1, the high-side switch M1 and the low-side switch M2 of the switch circuit 120-2 are turned on and off under the control of the pulse width modulation signal PWM2, and the high-side switch M1 and the low-side switch M2 of the switch circuit 120-n are turned on and off under the control of the pulse width modulation signal PWMn. Each switch M1 and M2 may include, for example, a metal oxide semiconductor field effect transistor, a bipolar transistor, or other types of transistors.

[0025] Figure 1 In the illustrated embodiment, each transformer includes a first winding and a second winding separated by an iron core, which may also be referred to as a primary winding and a secondary winding. The turns ratio between the primary winding and the secondary winding of each transformer may be, for example, 1:1. Each switching circuit 120 is coupled to the output voltage VOUT with the primary winding of the corresponding transformer as the output inductor Lo. The primary winding of each transformer includes a switch node terminal connected to the corresponding switch node, and an output voltage terminal connected to the output voltage VOUT. For example, the switch node terminal Vsw1 of the primary winding 121 of the transformer T1 is connected to the switch node SW1, and the output voltage terminal Vo_p1 of the primary winding 121 of the transformer T1 is connected to the output voltage VOUT. The switch node terminal Vsw2 of the primary winding 122 of the transformer T2 is connected to the switch node SW2, and the output voltage terminal Vo_p2 of the primary winding 121 of the transformer T2 is connected to the output voltage VOUT. The switch node terminal Vswn of the primary winding 12n of the transformer Tn is connected to the switch node SWn, and the output voltage terminal Vo_pn of the primary winding 12n of the transformer Tn is connected to the output voltage VOUT. The secondary windings 131-13n of the transformers T1-Tn are connected in series with the compensation inductor Lc to form a conductive inductor loop 103, and the conductive inductor loop 103 is connected to the output voltage VOUT. Figure 1As shown, the compensation inductor Lc includes a compensation voltage terminal 141 (i.e., Vlc terminal) and a reference terminal 142, wherein the compensation voltage terminal 141 is connected to the secondary winding 131 of the transformer T1, and the reference terminal 142 is connected to the secondary winding 13n of the transformer Tn and the output voltage VOUT. Figure 1 In the illustrated embodiment, each transformer includes a primary winding and a secondary winding. It is understood by those skilled in the art that the transformer in the embodiment of the present invention may also include multiple primary windings and / or multiple secondary windings.

[0026] Figure 2 FIG. 1 is a schematic diagram of a circuit structure of a multi-phase power supply 200 according to an embodiment of the present invention. The multi-phase power supply 200 includes an input terminal for receiving an input voltage VIN, an output terminal for providing an output voltage VOUT, a power stage circuit 100, and a control circuit 201 composed of a controller 300, an average current sampling circuit 22, and a sampling correction circuit 23. The output capacitor Co is coupled between the output terminal of the multi-phase power supply 200 and the reference ground GND. In one embodiment, the specific structure of the power stage circuit 100 is as follows: Figure 1 As shown. The controller 300 includes a current sampling terminal CSAN, a current sampling terminal CSAP, and a plurality of switch control terminals P1-Pn. The controller 300 provides a plurality of pulse width modulation signals PWM1-PWMn at the plurality of switch control terminals P1-Pn according to the output voltage VOUT and the signal between the current sampling terminal CSAN and the current sampling terminal CSAP to control the plurality of switch circuits in the power stage circuit 100. In one embodiment, the controller 300 further includes a voltage sampling terminal VOSP and a voltage sampling terminal VOSN respectively connected to both ends of the output capacitor Co to sample the output voltage VOUT. It will be appreciated by those skilled in the art that the multi-phase power supply 200 may also include other suitable voltage sampling circuits, such as a resistor voltage divider circuit, to sample the output voltage VOUT.

[0027] The average current sampling circuit 22 is connected to both ends of the primary winding of each transformer in the power stage circuit 100 to sample the average current flowing through the multiple switch circuits, thereby further obtaining the total current flowing through the multiple switch circuits. For example, the average current sampling circuit 22 is connected to both ends Vsw1 and Vo_p1 of the primary winding 121, both ends Vsw2 and Vo_p2 of the primary winding 122, ... and both ends Vswn and Vo_pn of the primary winding 12n, and is connected to the current sampling terminal CSAN and the current sampling terminal CSAP of the controller 300 to provide information representing the average current flowing through the multiple switch circuits. The sampling correction circuit 23 is connected to the compensation inductor Lc to sample the current flowing through the compensation inductor Lc, and is connected to the current sampling terminal CSAP of the controller 300 to inject the information obtained from the compensation inductor Lc into the current sampling terminal CSAP, thereby correcting the sampling result of the average current sampling circuit 22. In one embodiment, the sampling correction circuit 23 corrects the sampling result of the average current sampling circuit 22 in response to the transient change of the output current Io, wherein after the output current Io is stable, the sampling correction circuit 23 does not correct the sampling result of the average current sampling circuit 22. Figure 2 In the illustrated embodiment, the sampling correction circuit 23 is connected to the Vlc terminal of the compensation inductor Lc. In another embodiment, the sampling correction circuit 23 may also be connected to both ends of the compensation inductor Lc.

[0028] Figure 3 FIG. 2 shows a circuit diagram of a control circuit 201A according to an embodiment of the present invention. Figure 3 In the illustrated embodiment, the control circuit 201A includes an average current sampling circuit 22, a sampling correction circuit 23A, and a controller 300A. The average current sampling circuit 22 includes at least an average sampling capacitor C1 connected between the current sampling terminal CSAP and the current sampling terminal CSAN of the controller 300, and the sampling correction circuit 23A includes at least a correction capacitor C2 connected between the current sampling terminal CSAP and the compensation inductor Lc of the controller 300. When the output current Io changes transiently, due to the circuit characteristics of the power stage circuit 100, the current flowing through the compensation inductor Lc increases rapidly, and the sampling correction circuit 23A corrects the sampling result of the average current sampling circuit 22 according to the current flowing through the compensation inductor Lc, so that the signal received by the controller 300A through the current sampling terminal CSAP and the current sampling terminal CSAN can reflect the change of the output current Io in real time and accurately. After the output current Io stabilizes, the current flowing through the compensation inductor Lc tends to zero ampere, and the sampling correction circuit 23A does not correct the sampling result of the average current sampling circuit 22, thereby ensuring that the signals received through the current sampling terminal CSAP and the current sampling terminal CSAN can accurately reflect the average current of multiple switching circuits in both the transient and steady states of the output current Io.

[0029] exist Figure 3 In the illustrated embodiment, the average current sampling circuit 22 further includes a resistor network 23 and a resistor network 24. The resistor network 23 includes a plurality of resistors 23-1, 23-2, ... 23-n. One end of each resistor in the resistor network 23 is connected to the first end 311 of the average sampling capacitor C1, and the other end is connected to the output voltage VOUT through the output voltage end of the primary winding of the corresponding transformer. For example, one end of each resistor 23-1 to 23-n is connected to the first end 311 of the average sampling capacitor C1, the other end of the resistor 23-1 is connected to the output voltage end Vo_p1 of the primary winding 121, the other end of the resistor 23-2 is connected to the output voltage end Vo_p2 of the primary winding 122, and the other end of the resistor 23-n is connected to the output voltage end Vo_pn of the primary winding 12n. The resistor network 24 includes a plurality of resistors 24-1, 24-2 ... 24-n. One end of each resistor in the resistor network 24 is connected to the second end 312 of the average sampling capacitor C1, and the other end is connected to the corresponding switch node through the switch node end of the primary winding of the corresponding transformer. For example, one end of each resistor 24-1 to 24-n is connected to the second end 312 of the average sampling capacitor C1, the other end of the resistor 24-1 is connected to the switch node terminal Vsw1 of the primary winding 121, the other end of the resistor 24-2 is connected to the switch node terminal Vsw2 of the primary winding 122, and the other end of the resistor 24-n is connected to the switch node terminal Vswn of the primary winding 12n. The first end 311 of the average sampling capacitor C1 is connected to the current sampling terminal CSAN, and the second end 312 of the average sampling capacitor C1 is connected to the current sampling terminal CSAP. Figure 3 In the illustrated embodiment, the sampling correction circuit 23A further includes a resistor R2. One end of the resistor R2 is connected to the first end 321 of the correction capacitor C2, and the second end 322 of the correction capacitor C2 is connected to the current sampling terminal CSAP. The other end of the resistor R2 is connected to the compensation voltage terminal 141 of the compensation inductor Lc.

[0030] The controller 300A includes a switch control circuit 31, a sampling processing circuit 32, and a sampling processing circuit 33. The sampling processing circuit 32 provides a total current sampling signal Is_total according to a signal between a current sampling terminal CSAP and a current sampling terminal CSAN. The sampling processing circuit 33 provides a voltage feedback signal Vfb according to a signal between a voltage sampling terminal VOSP and a voltage sampling terminal VOSN. In one embodiment, the sampling processing circuit 32 includes a differential amplifier, whose non-phase input terminal is connected to the current sampling terminal CSAP of the controller 300A, whose inverting input terminal is connected to the current sampling terminal CSAN of the controller 300A, and whose output terminal provides a total current sampling signal Is_total according to a signal between the current sampling terminal CSAP and the current sampling terminal CSAN. In one embodiment, the sampling processing circuit 33 includes a differential amplifier, whose non-phase input terminal is connected to the voltage sampling terminal VOSP of the controller 300A, whose inverting input terminal is connected to the voltage sampling terminal VOSN of the controller 300A, and whose output terminal provides a voltage feedback signal Vfb according to a signal between the voltage sampling terminal VOSP and the voltage sampling terminal VOSN. The switch control circuit 31 generates a plurality of pulse width modulation signals PWM1 , PWM2 . . . PWMn according to the total current sampling signal Is_total and the voltage feedback signal Vfb.

[0031] Figure 4 The circuit diagram of the control circuit 201B according to an embodiment of the present invention is shown. The control circuit 201B includes an average current sampling circuit 22, a sampling correction circuit 23B, and a controller 300A. The sampling correction circuit 23B includes a correction capacitor C3 and a resistor R3. The first end 411 of the correction capacitor C3 is connected to the reference end 142 of the compensation inductor Lc, and the second end 412 of the correction capacitor C3 is connected to the current sampling end CSAP. In one embodiment, the second end 412 of the correction capacitor C3 is connected to the current sampling end CSAP through a resistor R5, that is, the average current sampling circuit 22 and the sampling correction circuit 23B are connected to the current sampling end CSAP through different resistors. In one embodiment, the resistance values ​​of the resistors R4 and R5 are much greater than the resistance values ​​of the resistors R3, R23-1 to R23-n, and R24-1 to R24-n. In one embodiment, by selecting appropriate resistance values ​​of the resistors R4 and R5, the correction strength of the sampling result of the average current sampling circuit 22 by the sampling correction circuit 23B can be set. One end of the resistor R3 is connected to the second end 412 of the correction capacitor C3 , and the other end of the resistor R3 is connected to the compensation voltage terminal 141 of the compensation inductor Lc.

[0032] Figure 5 The circuit diagram of the existing current sampling circuit 500 is shown. Figure 3 as well as Figure 4The difference is that the existing current sampling circuit 500 uses capacitor C5 to sample the average current flowing through the multiple switch circuits and the current flowing through the compensation inductor Lc. Similarly, the controller 300A provides a total current sampling signal Is_total according to the sampling result of the current sampling circuit 500 (i.e., the signal between the current sampling terminal CSAP and the current sampling terminal CSAN). Figure 5 In the illustrated embodiment, although the current sampling circuit 500 can compensate the sampling result through the resistor R11 when the output current Io changes transiently, after the output current Io stabilizes, the current sampling circuit 500 will over-compensate or reverse-compensate the sampling result, thereby causing the sampling result of the current sampling circuit 500 to be inaccurate after the output current Io stabilizes.

[0033] Figure 6 The waveform diagram of the total current sampling signal Is_total and the output current Io obtained according to the existing current sampling circuit 500 is shown. Curve 611 represents the output current Io, and curve 612 represents the total current sampling signal Is_total. At time t1, the output current Io increases rapidly from 10A to 100A. At this time, the current value represented by the total current sampling signal Is_total increases with the output current Io. However, as time goes by, after the output current Io stabilizes at 100A, the current value represented by the total current sampling signal Is_total gradually deviates from the output current Io, for example, the current value represented by the total current sampling signal Is_total gradually becomes smaller than the actual output current Io until it stabilizes.

[0034] Figure 7 The embodiment of the present invention is shown Figure 2 The waveform diagram of the total current sampling signal Is_total and the output current Io obtained by the multi-phase power supply 200 shown. Curve 711 represents the output current Io, and curve 712 represents the total current sampling signal Is_total. At time t2, the output current Io increases rapidly from 10A to 100A. At this time, the current value represented by the total current sampling signal Is_total increases with the output current Io. And after the output current Io stabilizes at 100A, the current value represented by the total current sampling signal Is_total still follows the output current Io.

[0035] Figure 8 The circuit structure diagram of the multi-phase power supply 800 according to an embodiment of the present invention is shown. The multi-phase power supply 800 includes a power stage circuit 100, a controller 300B, an average current sampling circuit 22, a sampling correction circuit 23, and a plurality of phase current sampling circuits 24-1, 24-2...24-n. The plurality of phase current sampling circuits 24-1, 24-2...24-n are used to sample the current flowing through each switch circuit, that is, the phase current. Figure 2 Compared with the embodiment shown, the controller 300B further includes phase current sampling terminals CS1, CS2...CSn. Each phase current sampling circuit is connected to the two ends of the primary winding of the corresponding transformer, and provides a phase current sampling signal to the corresponding phase current sampling terminal of the controller 300B. For example, the phase current sampling circuit 24-1 is connected to the switch node terminal Vsw1 and the output voltage terminal Vo_p1 of the primary winding 121, and provides the phase current sampling signal Is_ph1 to the phase current sampling terminal CS1 of the controller 300B, the phase current sampling circuit 24-2 is connected to the switch node terminal Vsw2 and the output voltage terminal Vo_p2 of the primary winding 122, and provides the phase current sampling signal Is_ph2 to the phase current sampling terminal CS2 of the controller 300B, and the phase current sampling circuit 24-n is connected to the switch node terminal Vswn and the output voltage terminal Vo_pn of the primary winding 12n, and provides the phase current sampling signal Is_phn to the phase current sampling terminal CSn of the controller 300B. In one embodiment, the sampling correction circuit 23 is further connected to each phase current sampling circuit, and corrects the sampling result of each phase current sampling circuit in response to the transient change of the output current Io, thereby ensuring that the sampling result of each phase current sampling circuit can accurately reflect the current flowing through the corresponding switch circuit in both the transient and steady state of the output current Io.

[0036] Fig. 9 FIG. 9 is a schematic diagram of a circuit structure of a plurality of phase current sampling circuits according to an embodiment of the present invention. Fig. 9 As shown, the phase current sampling circuit 24-1 includes, for example, a resistor R41_1, a capacitor C41_1, and a resistor R42_1. One end of the resistor R41_1 is connected to the switch node terminal Vsw1 of the primary winding 121, the other end of the resistor R41_1 is connected to one end of the capacitor C41, and the other end of the capacitor C41_1 is connected to the output voltage terminal Vo_p1 of the primary winding 121. One end of the resistor R42_1 is connected to the common end of the resistor R41_1 and the capacitor C41_1, and the other end of the resistor R42_1 is connected to the phase current sampling terminal CS1 of the controller 300B to provide a phase current sampling signal Is_ph1. In one embodiment, the sampling correction circuit 23 further includes a sub-correction circuit 23_1 for correcting the sampling result of the phase current sampling circuit 24-1 when the output current Io changes transiently. In one embodiment, after the output current Io stabilizes, the sub-correction circuit 23_1 does not correct the sampling result of the phase current sampling circuit 24-1. Fig. 9In the illustrated embodiment, the sub-correction circuit 23_1 includes a resistor R3_1, a correction capacitor C3_1, and a resistor R4_1. One end of the resistor R3_1 is connected to the compensation voltage terminal 141 of the compensation inductor Lc, the other end of the resistor R3_1 is connected to one end of the correction capacitor C3_1, and the other end of the correction capacitor C3_1 is connected to the reference terminal 142. One end of the resistor R4_1 is connected to the common end of the resistor R3_1 and the correction capacitor C3_1, and the other end of the resistor R4_1 is connected to the phase current sampling terminal CS1.

[0037] Fig.10 FIG. 3 is a schematic diagram of a circuit structure of a controller 300B according to an embodiment of the present invention. The controller 300B includes a switch control circuit 31, a sampling processing circuit 32, and a sampling processing circuit 33. Fig.10 In the illustrated embodiment, the switch control circuit 31 generates a plurality of pulse width modulation signals PWM1 , PWM2 . . . PWMn according to the total current sampling signal Is_total, the phase current sampling signals Is_ph1 , Is_ph2 . . . Is_phn, and the voltage feedback signal Vfb.

[0038] Fig.11 A control method 1100 of a multi-phase power supply according to an embodiment of the present invention is shown. The multi-phase power supply includes a plurality of transformers and a plurality of switch circuits, wherein each transformer includes a primary winding and a secondary winding, the secondary windings of the plurality of transformers and a compensation inductor are connected in series, and each switch circuit is coupled to the output voltage of the multi-phase power supply through the primary winding of the corresponding transformer, and the primary winding includes an output voltage terminal connected to the output voltage and a switch node terminal connected to the corresponding switch circuit. The control method 1100 includes steps S11 to S14.

[0039] In step S11, the average current flowing through the plurality of switch circuits is sampled by the average current sampling circuit. In step S12, in response to the transient change of the output current of the multi-phase power supply, the sampling result of the average current sampling circuit is corrected by the sampling correction circuit according to the current flowing through the compensation inductor, and after the output current is stable, the sampling result of the average current sampling circuit is not corrected. In step S13, a total current sampling signal is generated according to the sampling result of the corrected average current sampling circuit. In step S14, a plurality of pulse width modulation signals are generated according to the output voltage and the total current sampling signal to control the plurality of switch circuits.

[0040] In one embodiment, the average current sampling circuit includes at least an average sampling capacitor, and the average current sampling circuit provides a sampling result at both ends of the average sampling capacitor. In one embodiment, the sampling correction circuit includes at least a correction capacitor. The sampling correction circuit corrects the sampling result of the average current sampling circuit through the correction capacitor.

[0041] Fig.12 The control method 1200 of a multi-phase power supply according to an embodiment of the present invention is shown. The control method 1200 includes steps S21 to S26. In step S21, the average current flowing through the plurality of switch circuits is sampled by an average current sampling circuit. In step S22, in response to the transient change of the output current of the multi-phase power supply, the sampling result of the average current sampling circuit is corrected by a sampling correction circuit according to the current flowing through the compensation inductor, and after the output current is stable, the sampling result of the average current sampling circuit is not corrected. In step S23, a total current sampling signal is generated according to the sampling result of the corrected average current sampling circuit. In step S24, a plurality of phase current sampling circuits are respectively connected to the two ends of the primary windings of a plurality of transformers to sample the current flowing through each switch circuit. In step S25, in response to the transient change of the output current, the sampling results of the plurality of phase current sampling circuits are respectively corrected by a sampling correction circuit according to the current flowing through the compensation inductor to obtain a plurality of phase current sampling signals, and after the output current is stable, the sampling correction circuit does not correct the sampling result of the phase current sampling circuit. In step S26 , a plurality of pulse width modulation signals are generated according to the output voltage, the plurality of phase current sampling signals, and the total current sampling signal to control the plurality of switch circuits.

[0042] It should be noted that the execution order of the steps in the above flowchart is not limited to Figures 11-12 As shown, two consecutive function blocks may be executed simultaneously, or in reverse order.

[0043] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A control circuit for a multi-phase power supply, the multi-phase power supply comprising a plurality of transformers, wherein each transformer comprises a primary winding and a secondary winding, the secondary windings of the plurality of transformers and a compensation inductor are connected in series, the control circuit comprising: A controller, comprising a first current sampling terminal, a second current sampling terminal, and a plurality of switch control terminals, wherein the controller provides a plurality of pulse width modulation signals at the plurality of switch control terminals according to the output voltage of the multi-phase power supply and the signal between the first current sampling terminal and the second current sampling terminal, so as to respectively control a plurality of switch circuits of the multi-phase power supply; an average current sampling circuit connected to both ends of the primary winding of each transformer to sample the average current flowing through the plurality of switch circuits, wherein the current sampling circuit comprises an average sampling capacitor, a first end of the average sampling capacitor is connected to the first current sampling end, and a second end of the average sampling capacitor is connected to the second current sampling end; as well as A sampling correction circuit is connected to the compensation inductor, wherein the sampling correction circuit includes a correction capacitor, a first end of the correction capacitor is connected to the first end of the compensation inductor, and a second end of the correction capacitor is connected to the second current sampling end. The sampling correction circuit responds to transient changes in the output current of the multi-phase power supply and injects information obtained from the compensation inductor into the second current sampling end.

2. The control circuit as claimed in claim 1, wherein the average current sampling circuit further comprises: a plurality of first resistors, wherein one end of each first resistor is connected to a first end of an average sampling capacitor, and the other end of each first resistor is connected to an output voltage of a multi-phase power supply through one end of a primary winding of a corresponding transformer; as well as A plurality of second resistors, wherein one end of each second resistor is connected to the second end of the average sampling capacitor, and the other end of each second resistor is connected to the switch node of the corresponding switch circuit through the other end of the primary winding of the corresponding transformer.

3. The control circuit as claimed in claim 1, wherein the sampling correction circuit further comprises: A third resistor, wherein the first end of the correction capacitor is connected to the first end of the compensation inductor through the third resistor.

4. The control circuit as claimed in claim 1, wherein the sampling correction circuit further comprises: A fourth resistor, wherein one end of the fourth resistor is connected to the second end of the compensation inductor, and the other end of the fourth resistor is connected to the second end of the correction capacitor. 5 . The control circuit as claimed in claim 1 , wherein the second end of the average sampling capacitor is connected to the second current sampling end through a fifth resistor, and the second end of the correction capacitor is connected to the second current sampling end through a sixth resistor.

6. The control circuit of claim 1, further comprising: A plurality of phase current sampling circuits, each phase current sampling circuit being connected to both ends of the primary winding of a corresponding transformer to provide a plurality of phase current sampling signals to the controller; in The sampling correction circuit is further connected to each phase current sampling circuit, and corrects the plurality of phase current sampling signals respectively in response to transient changes in the output current of the multi-phase power supply.

7. A multiphase power supply comprising: an input terminal for receiving an input voltage and an output terminal for providing an output voltage; A plurality of transformers, each transformer comprising a primary winding and a secondary winding, the secondary windings of the plurality of transformers and a compensating inductor being connected in series; a plurality of switch circuits connected in parallel between the input terminal and the output terminal of the multi-phase power supply, each switch circuit being coupled to the output terminal of the multi-phase power supply through the primary winding of a corresponding transformer; and A control circuit as claimed in any one of claims 1 to 6.

8. A multi-phase power supply as described in claim 7, wherein each switching circuit includes a high-side switch and a low-side switch, a first end of the high-side switch is connected to the input end of the multi-phase power supply, a second end of the high-side switch is connected to the first end of the low-side switch to form a switching node, and a second end of the low-side switch is coupled to a reference ground, and the high-side switch and the low-side switch are controlled by corresponding pulse width modulation signals.

9. A control method for a multi-phase power supply, the multi-phase power supply comprising a plurality of transformers, wherein each transformer comprises a primary winding and a secondary winding, the secondary windings of the plurality of transformers and a compensation inductor are connected in series, the control method comprising: The average current of the plurality of switch circuits flowing through the multi-phase power supply is sampled by an average current sampling circuit; In response to transient changes in the output current of the multi-phase power supply, the sampling result of the average current sampling circuit is corrected by the sampling correction circuit according to the current flowing through the compensation inductor; generating a total current sampling signal according to the sampling result of the corrected average current sampling circuit; as well as A plurality of pulse width modulation signals are generated according to the output voltage and the total current sampling signal to control a plurality of switch circuits of the multi-phase power supply.

10. The control method according to claim 9, further comprising: sampling the current flowing through each switching circuit by means of a plurality of phase current sampling circuits; In response to transient changes in the output current of the multi-phase power supply, the sampling results of the multiple phase current sampling circuits are respectively corrected by the sampling correction circuit according to the current flowing through the compensation inductor to obtain multiple phase current sampling signals; and A plurality of pulse width modulation signals are further generated according to the plurality of phase current sampling signals.

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