阅读说明：本技术 多相开关变换器及其控制器和控制方法 (Multiphase switching converter, controller and control method thereof ) 是由 姜礼节 许彬慈 于 2021-01-29 设计创作，主要内容包括：本发明公开了多相开关变换器及其控制电路和控制方法。多相开关变换器包括多个开关电路,控制器包括：电压控制电路、总电流控制电路、分频电路、以及多个子控制电路,电压控制电路基于电压参考信号和输出电压产生导通控制信号,总电流控制电路基于电流参考信号和多个开关电路的总输出电流产生电流控制信号,分频电路根据导通控制信号在多个输出端产生多个分频信号,每个子控制电路基于相应的分频信号和电流控制信号产生相应的开关控制信号。(The invention discloses a multiphase switching converter, a control circuit and a control method thereof. The multiphase switching converter includes a plurality of switching circuits, and the controller includes: the voltage control circuit generates a conduction control signal based on a voltage reference signal and an output voltage, the total current control circuit generates a current control signal based on a current reference signal and a total output current of the plurality of switch circuits, the frequency division circuit generates a plurality of frequency division signals at a plurality of output ends according to the conduction control signal, and each sub-control circuit generates a corresponding switch control signal based on the corresponding frequency division signal and the corresponding current control signal.)

1. A controller for a multiphase switching converter including a plurality of switching circuits having outputs coupled together to provide an output voltage, the controller generating a plurality of switching control signals to control the plurality of switching circuits to conduct in sequence, the controller comprising:

a voltage control circuit coupled to output terminals of the plurality of switching circuits, and generating a turn-on control signal based on a voltage reference signal and an output voltage;

a total current control circuit generating a current control signal based on a current reference signal and a total output current of the plurality of switching circuits;

a frequency dividing circuit having an input terminal and a plurality of output terminals, wherein the input terminal is coupled to the voltage control circuit to receive the conduction control signal, and the frequency dividing circuit generates a plurality of frequency dividing signals at the plurality of output terminals according to the conduction control signal;

a plurality of over-current detection circuits, each over-current detection circuit having an input terminal and an output terminal, wherein the input terminal is coupled to the corresponding switch circuit, each over-current detection circuit detecting whether the corresponding switch circuit is over-current based on a current flowing through the corresponding switch circuit, and generating an over-current signal at the output terminal thereof; and

the current control circuit comprises a plurality of sub-control circuits, each sub-control circuit is provided with a first input end, a second input end, a third input end and an output end, wherein the first input end is coupled to the corresponding output end of the frequency dividing circuit to receive a frequency dividing signal, the second input end is coupled to the total current control circuit to receive a current control signal, the third input end is coupled to the output end of the corresponding over-current detection circuit to receive an over-current signal, and the output end generates a corresponding switch control signal based on the frequency dividing signal, the current control signal and the over-current signal.

2. The controller of claim 1, further comprising:

and a total current calculating circuit having a plurality of input terminals coupled to the plurality of switching circuits respectively to receive the plurality of current sampling signals and an output terminal providing a current feedback signal representing a total output current of the plurality of switching circuits based on the plurality of current sampling signals, wherein each current sampling signal represents a current flowing through the corresponding switching circuit.

3. The controller of claim 2, wherein the total current calculation circuit comprises:

a current summing circuit coupled to the plurality of switching circuits to receive a plurality of current sampling signals, the current summing circuit providing a current summing signal based on the plurality of current sampling signals, the current summing signal representing a sum of the plurality of current sampling signals; and

and the output circuit provides a current feedback signal at the output end of the output circuit according to the current addition signal.

4. The controller of claim 1, wherein the total current control circuit comprises:

a first comparator having a first input terminal receiving a current feedback signal representative of a total output current of the plurality of switching circuits, a second input terminal receiving a current reference signal, and an output terminal, the first comparator generating a current control signal at the output terminal based on the current feedback signal and the current reference signal.

5. The controller of claim 1, wherein the voltage control circuit comprises:

a second comparator having a first input terminal receiving a voltage feedback signal representative of the output voltage, a second input terminal receiving a voltage reference signal, and an output terminal, the second comparator generating a turn-on control signal at the output terminal based on the voltage feedback signal and the voltage reference signal.

6. The controller of claim 1, wherein the plurality of sub-control circuits comprises:

the logic circuit is provided with a first input end, a second input end, a third input end and an output end, wherein the first input end is coupled to the corresponding output end of the frequency dividing circuit to receive the frequency dividing signal, the second input end is coupled to the total current control circuit to receive the current control signal, the third input end is coupled to the corresponding output end of the over-current detection circuit to receive the over-current signal, and the output end generates a setting signal according to the frequency dividing signal, the current control signal and the over-current signal; and

the trigger circuit is provided with a set end, a reset end and an output end, wherein the set end is coupled to the logic circuit to receive the set signal, the reset end receives a conduction time length control signal for controlling the conduction time length of the corresponding switch circuit, and the output end is coupled to the corresponding switch circuit to provide the switch control signal.

7. The controller of claim 1, wherein the plurality of sub-control circuits control the turn-on time of the respective switching circuits based on the output voltage and the voltage reference signal when a total output current of the plurality of switching circuits is less than the current reference signal.

8. A controller for a multiphase switching converter including a plurality of switching circuits having outputs coupled together to provide an output voltage, the controller generating a plurality of switching control signals to control the plurality of switching circuits to conduct in sequence, the controller comprising:

a voltage control circuit coupled to output terminals of the plurality of switching circuits, and generating a turn-on control signal based on a voltage reference signal and an output voltage;

a total current control circuit coupled to the plurality of switching circuits and generating a current control signal based on the current reference signal and a total output current of the plurality of switching circuits;

a frequency dividing circuit having an input terminal and a plurality of output terminals, wherein the input terminal is coupled to the voltage control circuit to receive the conduction control signal, and the frequency dividing circuit generates a plurality of frequency dividing signals at the plurality of output terminals according to the conduction control signal; and

a plurality of sub-control circuits, each having a first input coupled to a respective output of the frequency dividing circuit to receive the frequency divided signal, a second input coupled to the total current control circuit to receive the current control signal, and an output, a respective switch control signal being generated at the output based on the frequency divided signal and the current control signal.

9. The controller of claim 8, wherein the total current control circuit comprises:

a first comparator having a first input terminal receiving a current feedback signal representative of a total output current of the plurality of switching circuits, a second input terminal receiving a current reference signal, and an output terminal, the first comparator generating a current control signal at the output terminal based on the current feedback signal and the current reference signal.

10. The controller of claim 8, wherein the voltage control circuit comprises:

a second comparator having a first input terminal receiving a voltage feedback signal representative of the output voltage, a second input terminal receiving a voltage reference signal, and an output terminal, the second comparator generating a turn-on control signal at the output terminal based on the voltage feedback signal and the voltage reference signal.

11. The controller of claim 8, wherein the plurality of sub-control circuits comprises:

a logic circuit having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is coupled to the corresponding output terminal of the frequency dividing circuit to receive the frequency dividing signal, the second input terminal is coupled to the total current control circuit to receive the current control signal, and the output terminal generates a setting signal according to the frequency dividing signal and the current control signal; and

the trigger circuit is provided with a set end, a reset end and an output end, wherein the set end is coupled to the logic circuit to receive the set signal, the reset end receives the conduction time length signal representing the conduction time length of the corresponding switch circuit, and the output end is coupled to the corresponding switch circuit to provide the switch control signal.

12. The controller of claim 8, wherein the plurality of sub-control circuits control the turn-on time of the respective switching circuits based on the output voltage and the voltage reference signal when a total output current of the plurality of switching circuits is less than the current reference signal.

13. A multiphase switching converter comprising:

a plurality of switching circuits having outputs coupled together to provide an output voltage; and

the controller of any one of claims 1 to 12.

14. A control method for a multiphase switching converter including a plurality of switching circuits having outputs coupled together to provide an output voltage, the control method comprising:

generating a turn-on control signal based on the voltage reference signal and the output voltage;

generating a current control signal based on a current reference signal and a total output current of the plurality of switching circuits; and

generating a plurality of switch control signals based on the conduction control signal and the current control signal to control the plurality of switch circuits to be sequentially conducted; wherein

When the total output current of the plurality of switch circuits is greater than the current reference signal, the current-phase switch circuit is kept turned off until the total output current of the plurality of switch circuits is less than the current reference signal, and the current-phase switch circuit is controlled to be turned on based on the output voltage and the voltage reference signal; and

when the current phase switching circuit is detected to be over-current, the current phase switching circuit is kept off, and the next phase switching circuit is controlled.

15. The control method of claim 14, wherein generating a plurality of switch control signals based on the conduction control signal and the current control signal comprises:

generating a plurality of frequency division signals based on the conduction control signal;

generating a plurality of setting signals based on the plurality of frequency division signals and the current control signals, and respectively setting the plurality of switch control signals to control the conduction time of the corresponding switch circuit; and

and controlling the turn-off time of the corresponding switching circuit according to the turn-on duration signal representing the turn-on duration of the corresponding switching circuit.

16. The control method of claim 14, further comprising:

receiving a plurality of current sample signals, wherein each current sample signal is representative of a current flowing through a corresponding switching circuit; and

providing a total output current of the plurality of switching circuits according to a sum of the plurality of current sampling signals.

Technical Field

The present invention relates to electronic circuits, and more particularly, to a multiphase switching converter, a controller thereof, and a control method thereof.

Background

In recent years, with the advent of high-performance processors, switching converters with smaller output voltage and larger output current are required, and the requirements on the thermal performance and dynamic response performance of the switching converters are also higher and higher. Multiphase switching converters are becoming more and more widely used with their superior performance. A multiphase switching converter includes a plurality of switching circuits having outputs coupled together to provide power to a load. However, it is necessary to design a multiphase switching converter that can provide overcurrent protection for each phase of the switching circuit and can also ensure stable operation of the multiphase switching converter.

Disclosure of Invention

The present invention is directed to solve the above problems in the prior art, and provides a multiphase switching converter, a controller and a control method thereof.

A controller for a multiphase switching converter according to an embodiment of the present invention, the multiphase switching converter including a plurality of switching circuits, outputs of the plurality of switching circuits being coupled together to provide an output voltage, the controller generating a plurality of switching control signals to control the plurality of switching circuits to be sequentially turned on, the controller comprising: a voltage control circuit coupled to output terminals of the plurality of switching circuits, and generating a turn-on control signal based on a voltage reference signal and an output voltage; a total current control circuit generating a current control signal based on a current reference signal and a total output current of the plurality of switching circuits; a frequency dividing circuit having an input terminal and a plurality of output terminals, wherein the input terminal is coupled to the voltage control circuit to receive the conduction control signal, and the frequency dividing circuit generates a plurality of frequency dividing signals at the plurality of output terminals according to the conduction control signal; a plurality of over-current detection circuits, each over-current detection circuit having an input terminal and an output terminal, wherein the input terminal is coupled to the corresponding switch circuit, each over-current detection circuit detecting whether the corresponding switch circuit is over-current based on a current flowing through the corresponding switch circuit, and generating an over-current signal at the output terminal thereof; and a plurality of sub-control circuits, each having a first input terminal coupled to a corresponding output terminal of the frequency dividing circuit to receive the frequency dividing signal, a second input terminal coupled to the total current control circuit to receive the current control signal, a third input terminal coupled to an output terminal of the corresponding over-current detection circuit to receive the over-current signal, and an output terminal generating a corresponding switch control signal based on the frequency dividing signal, the current control signal, and the over-current signal.

A controller for a multiphase switching converter according to an embodiment of the present invention, the multiphase switching converter including a plurality of switching circuits, outputs of the plurality of switching circuits being coupled together to provide an output voltage, the controller generating a plurality of switching control signals to control the plurality of switching circuits to be sequentially turned on, the controller comprising: a voltage control circuit coupled to output terminals of the plurality of switching circuits, and generating a turn-on control signal based on a voltage reference signal and an output voltage; a total current control circuit coupled to the plurality of switching circuits and generating a current control signal based on the current reference signal and a total output current of the plurality of switching circuits; a frequency dividing circuit having an input terminal and a plurality of output terminals, wherein the input terminal is coupled to the voltage control circuit to receive the conduction control signal, and the frequency dividing circuit generates a plurality of frequency dividing signals at the plurality of output terminals according to the conduction control signal; and a plurality of sub-control circuits, each having a first input coupled to a corresponding output of the frequency dividing circuit to receive the frequency divided signal, a second input coupled to the total current control circuit to receive the current control signal, and an output, and generating a corresponding switch control signal at the output based on the frequency divided signal and the current control signal.

A multiphase switching converter in accordance with an embodiment of the present invention includes a plurality of switching circuits having outputs coupled together to provide an output voltage; and a controller as described above.

A control method for a multiphase switching converter including a plurality of switching circuits having outputs coupled together to provide an output voltage in accordance with an embodiment of the invention, the control method comprising: generating a turn-on control signal based on the voltage reference signal and the output voltage; generating a current control signal based on a current reference signal and a total output current of the plurality of switching circuits; generating a plurality of switch control signals based on the conduction control signals and the current control signals so as to control the plurality of switch circuits to be sequentially conducted; when the total output current of the plurality of switch circuits is greater than the current reference signal, the current-phase switch circuit is kept turned off until the total output current of the plurality of switch circuits is less than the current reference signal, and the current-phase switch circuit is controlled to be turned on based on the output voltage and the voltage reference signal; and when the current phase switching circuit is detected to be over-current, the current phase switching circuit is kept off, and the next phase switching circuit is controlled.

In the embodiment of the invention, the control of the total output current by the multi-phase switching converter increases the safety of the system, so that the multi-phase switching converter can automatically and smoothly switch between the regulation of the output voltage and the regulation of the total output current, and the imbalance of the current among the switching circuits caused by the continuous increase of the total output current is avoided.

Drawings

FIG. 1 shows a block circuit diagram of a multiphase switching converter 100 in accordance with an embodiment of the invention;

FIG. 2 illustrates a flow chart 200 of a method of controlling the multiphase switching converter 100 in accordance with an embodiment of the invention;

FIG. 3 illustrates a circuit schematic of the sub-control circuit 25-i of FIG. 1 according to an embodiment of the present invention;

FIG. 4 illustrates a circuit schematic of the total current control circuit 26 of FIG. 1 in accordance with an embodiment of the present invention;

FIG. 5 illustrates a state transition diagram 200 for the frequency divider circuit 22 of FIG. 1 in accordance with an embodiment of the present invention;

fig. 6 shows a block circuit diagram of a multiphase switching converter 100 according to another embodiment of the invention;

FIG. 7 shows a block circuit diagram of the controller 20 according to another embodiment of the present invention; and

fig. 8 shows a flow chart 800 of the operation of a multiphase switching converter in accordance with an embodiment of the invention.

Detailed Description

Specific embodiments of the present invention will be described in detail below, and 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, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: it is not necessary to employ these specific details to practice the present invention. In other instances, well-known circuits, materials, or methods have not been described in detail in order to avoid obscuring the present invention.

Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," "one example" or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Like reference numerals refer to like elements. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Embodiments of the present invention provide a multiphase switching converter including a plurality of switching circuits, each of which is sequentially turned on based on an output voltage of the multiphase switching converter and a total output current of the plurality of switching circuits in a normal operation state. When the total output current of the plurality of switch circuits is greater than the current reference signal, the multiphase switch converter controls the corresponding switch circuit to be temporarily non-conductive until the total output current of the plurality of switch circuits is less than the current reference signal, and the multiphase switch converter controls the corresponding switch circuit to be conductive based on the output voltage. And when the current phase switching circuit is detected to be overcurrent, the multiphase switching converter skips the current phase switching circuit and keeps the other phase switching circuits to work normally. In the embodiment of the present invention, the "current-phase switching circuit" or the "corresponding switching circuit" refers to a switching circuit that should be turned on in order. The embodiments are described below by taking as an example a multiphase switching converter using constant on-time control.

Fig. 1 shows a block circuit diagram of a multiphase switching converter 100 according to an embodiment of the invention. The multiphase switching converter 100 includes a controller 20 and a plurality of switching circuits 10-1,10-2, … … 10-n, where n is an integer greater than or equal to 2. The switching circuits 10-1,10-2 … … 10-n have input terminals receiving an input voltage Vin and output terminals coupled together to provide an output voltage Vo to power the load 102. The switching circuits 10-1,10-2, … … 10-n may employ any direct current/direct current (DC/DC) or alternating current/direct current (AC/DC) conversion topology, such as synchronous or asynchronous boost and buck converters, as well as forward and flyback converters, and the like. The output capacitor 105 is coupled between the output of the switching circuit 10-1,10-2, … … 10-n and ground reference.

The controller 20 generates a plurality of control signals PWM1, PWM2, … … PWMn to control the plurality of switching circuits 10-1,10-2, … … 10-n to be turned on sequentially. The controller 20 includes a voltage control circuit 21, a frequency dividing circuit 22, a total current control circuit 23, and a plurality of sub-control circuits 25-1, 25-2, … … 25-n. The voltage control circuit 21 is coupled to the output terminals of the plurality of switching circuits 10-1,10-2, … … 10-n and generates the turn-on control signal Set based on the voltage reference signal Vref and the output voltage Vo, for example, based on a comparison of the voltage reference signal Vref and a voltage feedback signal Vfb representative of the output voltage Vo. The frequency dividing circuit 22 has an input terminal and a plurality of output terminals, wherein the input terminal of the frequency dividing circuit 22 is coupled to the voltage control circuit 21 to receive the turn-on control signal Set, and the frequency dividing circuit 22 generates a plurality of frequency dividing signals FD1, FD2, … … FDn at the plurality of output terminals thereof according to the turn-on control signal Set. The total current control circuit 23 generates a current control signal Ictrl based on the current reference signal Iref0 and the total output current Io of the plurality of switching circuits, for example, based on a comparison of the current reference signal Iref0 and a current feedback signal Imon representing the total output current Io. Each sub-control circuit 25-i (i ═ 1,2, … … n) has a first input, a second input, and an output, wherein the first input of sub-control circuit 25-i is coupled to the respective output of frequency dividing circuit 22 to receive frequency divided signal FDi, the second input of sub-control circuit 25-i is coupled to total current control circuit 23 to receive current control signal Ictrl, and sub-control circuit 25-i generates a respective switch control signal PWMi at its output based on frequency divided signal FDi and current control signal Ictrl. In one embodiment, when the total output current Io or the current feedback signal Imon of the plurality of switching circuits is greater than the current reference signal Iref0, the multiphase switching converter 100 controls the current-phase switching circuit to be temporarily non-conductive until the total output current Io or the current feedback signal Imon of the plurality of switching circuits is less than the current reference signal Iref0, and the multiphase switching converter 100 controls the current-phase switching circuit to be conductive based on the output voltage Vo, for example, when the output voltage Vo or the voltage feedback signal Vfb is less than the voltage reference signal Vref.

In one embodiment, controller 20 further includes a plurality of over-current detection circuits 24-1,24-2, … … 24-n. Each of the over-current detection circuits 24-i (i ═ 1,2, … … n) has an input terminal and an output terminal, the input terminal of the over-current detection circuit 24-i is coupled to the corresponding switch circuit 10-i, and the over-current detection circuit 24-i detects whether the corresponding switch circuit 10-i is over-current based on the current flowing through the corresponding switch circuit 10-i, and generates an over-current signal OCi at its output terminal. For example, based on a current sampling signal CSi (i ═ 1,2, … … n) representative of the current flowing through the corresponding switch circuit 10-i, it is detected whether the corresponding switch circuit 10-i is overcurrent, and an overcurrent signal OCi is generated. In one embodiment, when an overcurrent is detected in the current phase switching circuit, the multiphase switching converter 100 skips the current phase switching circuit and keeps the remaining phase switching circuits operating normally. In one embodiment, the sub-control circuits 25-i (i ═ 1,2, … … n) further include a third input coupled to the output of the corresponding over-current detection circuit 24-i to receive the over-current signal OCi, and the outputs of the sub-control circuits 25-i generate the corresponding switch control signals PWMi based on the frequency-divided signal FDi, the current control signal Ictrl, and the over-current signal OCi.

In one embodiment, the controller 20 further includes a total current calculating circuit 26 having a plurality of inputs and an output, the plurality of inputs of the total current calculating circuit 26 being coupled to the plurality of switching circuits 10-1,10-2, … … 10-n respectively to receive the plurality of current sampling signals CS1, CS2, … … CSn, the output of the total current calculating circuit 26 providing a current feedback signal Imon representing the total output current of the plurality of switching circuits 10-1,10-2, … … 10-n according to the plurality of current sampling signals CS1, CS2, … … CSn. Wherein the current sampling signals CS1, CS2, … … CSn respectively represent the current flowing through the corresponding switch circuit.

In one embodiment, the multiphase switching converter 100 further includes a voltage sampling circuit 101. The voltage sampling circuit 101 samples the output voltage Vo and generates a voltage feedback signal Vfb according to the output voltage Vo. In one embodiment, the controller 20 further includes a slope compensation circuit that generates a slope compensation signal that can be superimposed on the output voltage Vo or a voltage feedback signal Vfb representative of the output voltage Vo, and subtracted from the voltage reference signal Vref.

FIG. 2 shows a flowchart 200 of a method of controlling the multiphase switching converter 100, including steps S21-S26, in accordance with an embodiment of the invention.

In step S21, control of the current-phase switch circuit 10-i is started.

In step S22, it is determined whether the total output current Io is smaller than the current reference signal Iref0, if yes, the process goes to step S23, otherwise, the determination is continued.

In step S23, it is determined whether the output voltage Vo is less than the voltage reference signal Vref, if yes, the step S24 is executed, otherwise, the step S22 is executed.

In step S24, it is determined whether the current phase switch circuit 10-i is overcurrent, if so, the process goes to step S26, otherwise, the process goes to step S25.

In step S25, the current-phase switch circuit 10-i is turned on, followed by step S26.

In step S26, control of the next-phase switch circuit is entered.

According to the embodiment of the invention, the control of the total output current by the multi-phase switching converter increases the safety of the CPU load, so that the multi-phase switching converter can automatically and smoothly switch between the regulation of the output voltage and the regulation of the total output current, and the imbalance of the current among the switching circuits caused by the continuous increase of the total output current is avoided.

Fig. 3 shows a circuit schematic of the sub-control circuit 25-i of fig. 1 according to an embodiment of the invention. In the embodiment shown in FIG. 3, sub-control circuit 25-i includes a logic circuit 251 and a trigger circuit 252. The logic circuit 251 has a first input terminal coupled to the corresponding output terminal of the frequency divider circuit 22 for receiving the frequency-divided signal FDi, a second input terminal coupled to the total current control circuit 23 for receiving the current control signal Ictrl, and an output terminal for generating the set signal SETi according to the frequency-divided signal FDi and the current control signal Ictrl. In one embodiment, the logic circuit 251 further has a third input terminal receiving the over-current signal OCi, and the logic circuit 251 generates the set signal SETi at its output terminal according to the frequency-divided signal FDi, the current control signal Ictrl, and the over-current signal OCi. The trigger circuit 252 has a set terminal S coupled to the logic circuit 251 for receiving the set signal SETi, a reset terminal R for receiving the on-time control signal COTi for controlling the on-time of the corresponding switch circuit 10-i, and an output terminal Q coupled to the corresponding switch circuit 10-i for providing the switch control signal PWMi.

In one embodiment, sub-control circuits 25-i further include on-period control circuit 253. The on-time control circuit 253 generates an on-time control signal COTi according to the switch control signal PWMi and the on-time signal TONi to control the on-time of the corresponding switch circuit 10-i. The on-time period TONi of the switch circuit 10-i may be set to a constant value or may be a variable value related to the input voltage Vin and/or the output voltage Vo.

Fig. 4 shows a circuit schematic of the total current calculation circuit 26 of fig. 1 according to an embodiment of the present invention. In one embodiment, total current calculation circuit 26 includes a current summing circuit 261 and an output circuit 262. The current summing circuit 261 is coupled to the plurality of switching circuits 10-1,10-2, … … 10-n to receive the plurality of current sampling signals CS1, CS2, … … CSn, and provides a current summing signal Iinh, representing the sum of the plurality of current sampling signals CS1+ CS2+ … … + CSn, based on the plurality of current sampling signals CS1, CS2, … … CSn. The output circuit 262 provides at its output a current feedback signal Imon representing the total output current of the plurality of switching circuits based on the current addition signal Iinh. In one embodiment, the current summing circuit 261 includes a plurality of resistors 26-1,26-2, … … 26-n, each resistor 26-i (i ═ 1,2, … … n) having one end receiving a respective current sample signal CSi and another end coupled together to provide a current sum signal Iinh. In one embodiment, the output circuit 262 includes a current mirror 263, a bias circuit 264, and an output resistor 265. The input end of the current mirror 263 receives the current addition signal Iinh, the bias end is coupled to the bias circuit 264, and the output end outputs the mirror current Iexh of the current addition signal Iinh. The mirror current Iexh flows through the output resistor 265, and a voltage is generated across the output resistor 265 as a current feedback signal Imon. In one embodiment, the current feedback signal Imon may be represented by the following formula (1).

Imon＝Gain*(CS1+CS2+……+CSn)+Bias (1)

Where Bias represents the voltage at the Bias terminal of the output circuit 262. Gain represents the Gain provided by the current addition circuit 261 and the current mirror 263.

Fig. 5 illustrates a state transition diagram 500 for the divider circuit 22 of fig. 1, including state 50, states 50-1, 50-2, … … 50-n, in accordance with an embodiment of the present invention.

In state 50, divider circuit 22 completes the initial configuration before transitioning to state 51-1.

In the state 51-1, when the on control signal Set is active, for example, at a high level, the frequency division signal FD1 is active, for example, becomes a high level. When the switch control signal PWM1 controls the switch circuit 10-1 to conduct, for example, when the PWM1 is 1, or when an overcurrent is detected in the switch circuit 10-1, the state transitions to state 51-2.

In the state 51-2, when the on control signal Set is active, for example, at a high level, the frequency division signal FD2 is active, for example, becomes a high level. When the switch control signal PWM2 controls the switch circuit 10-2 to conduct, for example, when the PWM2 is 1, or when the switch circuit 10-2 is detected to be overcurrent, the next state is shifted. Until state 51-n is entered.

In state 51-n, when the on-control signal Set is active, e.g., high, the frequency-divided signal FDn is active, e.g., goes high. When the switch control signal PWMn controls the switch circuit 10-n to be on, for example, PWMn is 1, or an overcurrent is detected in the switch circuit 10-n, the state transitions to the state 51-1. This is repeated.

Fig. 6 shows a block circuit diagram of a multiphase switching converter 100 according to another embodiment of the invention. In the embodiment shown in fig. 6, the switching circuits 10-i (i ═ 1,2, … … n) comprise a driver circuit 61-i, an upper switching tube 62-i, a lower switching tube 63-i, and an inductor 64-i, each switching circuit 10-i further comprising a current sampling circuit 65-i for sampling the current flowing through the switching circuit 10-i, for example the current flowing through the inductor 64-i, or the current flowing through the upper switching tube 62-i and/or the lower switching tube 63-i, and providing a current sampling signal CSi.

Fig. 7 shows a block circuit diagram of the controller 20 according to another embodiment of the present invention. In the embodiment shown in fig. 7, the voltage control circuit 21 includes a comparator CMP1 having a non-inverting input terminal receiving the voltage reference signal Vref, an inverting input terminal receiving the voltage feedback signal Vfb, and an output terminal generating the turn-on control signal Set according to a comparison result of the voltage feedback signal Vfb and the voltage reference signal Vref. The total current control circuit 23 includes a comparator CMP2 having a non-inverting input terminal receiving the current reference signal Iref0, an inverting input terminal receiving the current feedback signal Imon, and an output terminal generating a current control signal Ictrl based on a comparison of the current feedback signal Imon and the current reference signal Iref 0. When the current feedback signal Imon is smaller than the reference signal Iref0 and the voltage feedback signal Vfb is smaller than the voltage reference signal Vref, the controller 20 controls the current-phase switching circuit to be turned on. In the embodiment shown in fig. 7, the over-current detection circuit 24-1 includes, for example, a comparator CP1 having a non-inverting input terminal receiving the current sampling signal CS1, an inverting input terminal receiving the first current threshold ILIM1, and an output terminal outputting the over-current signal OC1 based on a comparison result of the current sampling signal CS1 and the first current threshold ILIM 1. When the current sampling signal CS1 is greater than the first current threshold ILIM1, the over current signal OC1 goes high indicating that the first phase switch circuit 10-1 is over current. The over-current detection circuit 24-2 includes, for example, a comparator CP2 having a non-inverting input terminal receiving the current sampling signal CS2, an inverting input terminal receiving the second current threshold ILIM2, and an output terminal outputting an over-current signal OC2 based on a comparison result of the current sampling signal CS2 and the second current threshold ILIM 2. When the current sampling signal CS2 is greater than the second current threshold ILIM2, the over current signal OC2 goes high indicating that the second phase switch circuit 10-2 is over current. By analogy, the over-current detection circuit 24-n for example comprises a comparator CPn having a non-inverting input terminal receiving the current sampling signal CSn, an inverting input terminal receiving the nth current threshold ILIMn, and an output terminal outputting the over-current signal OCn based on a comparison of the current sampling signal CSn and the nth current threshold ILIMn. When the current sampling signal CSn is greater than the nth current threshold ILIMn, the overcurrent signal OCn changes to a high level, indicating that the nth phase switching circuit 10-n is overcurrent.

FIG. 8 shows a flowchart 800 of the operation of a multiphase switching converter according to an embodiment of the invention, including steps S81-S85.

In step S81, a turn-on control signal is generated based on the voltage reference signal and the output voltage.

In step S82, a current control signal is generated based on the current reference signal and the total output current of the plurality of switching circuits.

In step S83, a plurality of switch control signals are generated based on the turn-on control signal and the current control signal to control the plurality of switch circuits to turn on in sequence.

In step S84, when the total output current of the plurality of switching circuits is greater than the current reference signal, the current-phase switching circuit remains off until the total output current of the plurality of switching circuits is less than the current reference signal, and the current-phase switching circuit is controlled to be on based on the output voltage and the voltage reference signal.

In step S85, when overcurrent is detected in the current-phase switching circuit, the current-phase switching circuit remains off, and control is performed on the next-phase switching circuit.

Note that in the flowcharts described above, functions noted in the blocks may also occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the particular functionality involved.

While the present invention has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.