Control circuits, control methods, and multiphase power supplies for multiphase power conversion circuits

Abstract

This invention discloses a control circuit, control method, and multiphase power supply for a multiphase power conversion circuit. The multiphase power conversion circuit includes multiple switching circuits, the output terminals of which are coupled together to provide an output voltage to power a load. The control circuit includes: a feedback control circuit that generates a feedback control signal based on a feedback signal characterizing the output voltage and a reference voltage signal; a multiphase power supply control circuit that includes multiple PWM controllers corresponding one-to-one with the multiple switching circuits, each PWM controller providing a pulse width modulation signal based on the feedback control signal and the current sampling signal of the corresponding switching circuit; and a phase number control circuit adapted to adjust the effective state of each of the multiple enable signals according to the sampled current characterizing the inductor current in the first switching circuit among the multiple switching circuits, so as to control the corresponding switching circuit to operate in an on state or in an off state, wherein the multiple enable signals correspond one-to-one with the multiple switching circuits.

Description

Technical Field

[0001] This invention relates to the field of switching power supply technology, and in particular to a control circuit, control method, and multiphase power supply for a multiphase power conversion circuit. Background Technology

[0002] Multiphase power supplies utilize a technique that connects multiple power conversion circuits in parallel and distributes the switching modulation process across different phases to achieve power supply regulation and control. This technology is suitable for high-current or high-power applications. In multiphase power supplies, the pulse width modulation (PWM) signals between phases can be identical or staggered by a certain phase. This ensures that the fluctuation frequency observed at the output and input is the product of the switching frequency of each phase and the number of phases. This reduces the need for filter capacitors and lowers the current surge to the input, while also accelerating the response to load changes.

[0003] Figure 1 A schematic circuit diagram of a multiphase power supply according to the prior art is shown. (e.g.) Figure 1 As shown, the existing multiphase power supply 100 includes a multiphase power controller 110 and a multiphase power conversion circuit including switching circuits 101-103. Figure 1 (Taking a 3-phase multiphase power supply as an example) and a feedback control circuit 120. Each phase power conversion circuit includes a drive unit, transistor T1, transistor T2, inductor Ls, resistor R4, and capacitor C3. Transistors T1 and T2 are connected in series between the input voltage VIN and ground. The first end of inductor Ls is coupled to the midpoint between transistors T1 and T2, and the second end is connected to the first end of resistor R4. The first end of capacitor C3 is coupled to the second end of resistor R4, and the second end is grounded. The drive unit receives an enable signal ENn. When the enable signal ENn is active, the drive units in each power conversion circuit 101-103 receive pulse width modulation signals PWM1-PWM3 provided by the multiphase power controller 110, and control the corresponding transistors to turn on and off according to the received pulse width modulation signals. The output voltages of the multiphase power conversion circuits 101-103 are combined into a single output voltage Vout to drive the load RL. When the enable signal ENn is in an invalid state, the drive unit turns off transistors T1 and T2, thereby shutting down the phase switching circuit.

[0004] The feedback control circuit 120 includes resistors R1 and R2, an error amplifier 121, and a signal processing unit 122. Resistors R1 and R2 are connected in series between the output voltage Vout and ground. The negative input terminal of the error amplifier 121 is coupled to the midpoint between resistors R1 and R2 to receive the feedback signal VFB after the output voltage Vout is divided. Its positive input terminal receives the reference voltage signal VREF. The error amplifier 121 is adapted to generate an error amplification signal Vc based on the comparison result of the feedback signal VFB and the reference voltage signal VREF. The signal processing unit 122 performs amplitude modulation, filtering, and other processing on the error amplification signal Vc to generate a feedback control signal Vc1. The feedback control signal Vc1 is provided to the multiphase power control circuit 110 so that each PWM controller 111-113 determines the working order of the multiphase power conversion circuits 101-103 according to the feedback control signal Vc1, thereby providing pulse width modulation signals PWM1-PWM3.

[0005] In existing multiphase power conversion circuits and multiphase power supplies, the error amplification signal Vc is compared with the upper threshold voltage VH and the lower threshold voltage VL to change the effective state of each enable signal, thereby controlling the number of switching circuits that are turned on. For example, when the error amplification signal Vc is greater than the upper threshold voltage VH, a switching circuit that is in the off state is switched to the on state; when the error amplification signal Vc is less than the lower threshold voltage VL, a switching circuit that is in the on state is switched to the off state. However, when the number of phases is large (e.g., 16 phases), the change in the error amplification signal Vc is very small when the number of phases changes. On the one hand, this makes it impossible to accurately set the upper threshold voltage VH and the lower threshold voltage VL; on the other hand, the low accuracy of the comparator can also easily lead to control failure. These problems are particularly obvious when switching a large number of phases in a multiphase power supply, such as switching from 16 phases to 15 phases.

[0006] Therefore, there is a need for an improved control circuit, control method, and multiphase power supply for multiphase power conversion circuits to solve the above problems. Summary of the Invention

[0007] In view of the above problems, the purpose of this invention is to provide a control circuit, control method and multiphase power supply for a multiphase power conversion circuit, which uses an analog-to-digital converter to sample the inductor current of the switching circuit, thereby improving the control accuracy of the multiphase power supply when the number of phases increases or decreases.

[0008] According to one aspect of this application, a control circuit for a multiphase power conversion circuit is provided. The multiphase power conversion circuit includes multiple switching circuits, the output terminals of which are coupled together to provide an output voltage to power a load. The control circuit includes: a feedback control circuit that generates a feedback control signal based on a feedback signal characterizing the output voltage and a reference voltage signal; a multiphase power supply control circuit that includes multiple PWM controllers corresponding one-to-one with the multiple switching circuits, each PWM controller providing a pulse width modulation signal based on the feedback control signal and a current sampling signal of the corresponding switching circuit; and a phase number control circuit adapted to adjust the effective state of each of a plurality of enable signals based on a sampling current characterizing the inductor current in a first switching circuit among the plurality of switching circuits, so as to control the corresponding switching circuit to operate in an on state or in an off state, wherein the plurality of enable signals correspond one-to-one with the plurality of switching circuits.

[0009] Optionally, the phase control circuit includes: an analog-to-digital converter unit, which receives the sampled current of the first switching circuit and generates a first intermediate signal based on the sampled current; a second comparator, adapted to compare a second threshold signal with the first intermediate signal and generate a subtractive phase signal based on the comparison result; a third comparator, adapted to compare the first threshold signal with the first intermediate signal and generate an incremental phase signal based on the comparison result; and an enable unit, which changes the number of enabled signals in a valid state among the multiple enabled signals it generates based on the valid state of the received incremental and / or subtractive phase signals, switching an invalid enabled signal to a valid state when a valid incremental phase signal is received, and switching an valid enabled signal to an invalid state when a valid subtractive phase signal is received.

[0010] Optionally, the phase control circuit is configured such that when the sampling current of the first switching circuit is greater than the first threshold signal, the third comparator generates an increasing phase signal in an active state; and when the sampling current of the first switching circuit is less than the second threshold signal, the second comparator generates a decreasing phase signal in an active state.

[0011] Optionally, switching an invalid enable signal to an valid state includes, according to the sequence number of the plurality of switch circuits, the enable unit switches the enable signal corresponding to the switch circuit with the smallest sequence number that is in an invalid state to a valid state; or the switching of a valid enable signal to an invalid state includes, according to the sequence number of the plurality of switch circuits, the enable unit switches the enable signal corresponding to the switch circuit with the largest sequence number that is in a valid state to an invalid state.

[0012] Optionally, if the first threshold signal is greater than the second threshold signal, and the sampling current of the first switching circuit is greater than the second threshold signal but less than the first threshold signal, the enabling unit does not change the effective state of any of the plurality of enabling signals.

[0013] Optionally, the feedback control circuit includes: an error amplifier, adapted to compare the feedback signal of the output voltage with a reference voltage signal and generate an error amplification signal based on the comparison result; and a signal processing unit, adapted to filter and / or amplitude modulate the error amplification signal to generate the feedback control signal.

[0014] Optionally, the feedback control circuit further includes a first resistor and a second resistor connected in series between the output voltage and ground, wherein the intermediate node between the first resistor and the second resistor provides the feedback signal.

[0015] Optionally, the signal processing unit includes: a second capacitor coupled between the output terminal of the error amplifier and ground; a third resistor and a first capacitor connected in series between the output terminal of the error amplifier and ground; and an amplitude modulation unit configured to perform amplitude modulation processing on the error amplified signal to generate the feedback control signal.

[0016] Optionally, the phase number control circuit is further configured to switch all enable signals to an active state when the error amplification signal is greater than the third threshold signal.

[0017] Optionally, the third threshold signal is slightly greater than one-quarter of the full-load current.

[0018] Optionally, the phase number control circuit further includes a fourth comparator, adapted to compare the error amplification signal with the third threshold signal and generate a set signal; when the enable unit receives the set signal in an effective state, it sets all of the plurality of enable signals it provides to an effective state.

[0019] Optionally, the second, third, and fourth comparators are selected from Schmitt triggers.

[0020] Optionally, the PWM controller includes: a sampling unit adapted to generate the current sampling signal based on the sampling current flowing through the inductor in the switching circuit; a first comparator, whose positive input terminal receives the current sampling signal, and whose first negative input terminal receives the feedback control signal, and generates a reset signal based on the comparison result of the current sampling signal and the feedback control signal; and a first flip-flop, whose reset terminal is coupled to the output terminal of the first comparator to receive the reset signal, whose set terminal receives a clock signal, and whose output terminal provides the pulse width modulation signal based on the reset signal and the clock signal.

[0021] Optionally, the first comparator further includes a second negative input for receiving a ripple injection signal to perform ripple compensation on the current sampling signal.

[0022] Optionally, when at least one of the plurality of switching circuits is in the ON state, the enable signal of the first switching circuit is always in the OFF state.

[0023] Optionally, the second comparator, the third comparator, and the enable unit are selected from digital logic circuits, and the fourth comparator is selected from analog circuits.

[0024] According to another aspect of the present invention, a multiphase power supply is provided, comprising: a multiphase power conversion circuit including a plurality of switching circuits, the output terminals of the plurality of switching circuits being coupled together to supply power to a load; and a control circuit as described in any of the preceding claims.

[0025] Optionally, the switching circuit includes: a main switch transistor adapted to control the power transfer from the input terminal to the output terminal; and a driving unit configured to control the conduction state of the main switch transistor according to a pulse width modulation signal, thereby generating the output voltage according to the input voltage; wherein the driving unit is further configured to turn the main switch transistor on or off according to the valid state of an enable signal.

[0026] Optionally, the driving unit is configured to: control the main switch to turn on and off according to the pulse width modulation signal when the enable signal is active; and turn off the main switch when the enable signal is inactive.

[0027] According to another aspect of the present invention, a control method for a multiphase power circuit is provided. The multiphase power circuit includes multiple switching circuits, the output terminals of which are coupled together to provide an output voltage to power a load. The control method includes: sampling the inductor current of a first switching circuit among the multiple switching circuits to obtain a sampled current; converting the sampled current into a digital signal and comparing it with a first threshold signal and a second threshold signal respectively; and controlling the effective state of multiple enable signals corresponding one-to-one with the multiple switching circuits according to the comparison result, thereby controlling the corresponding switching circuit to operate in an on state or an off state.

[0028] Optionally, when the sampling current is greater than the first threshold signal, one of the plurality of enable signals that is in an invalid state is switched to an active state; when the sampling current is less than the second threshold signal, one of the plurality of enable signals that is in an active state is switched to an invalid state.

[0029] Optionally, switching one of the plurality of enable signals from an invalid state to an active state includes switching the enable signal corresponding to the switch circuit with the smallest sequence number that is in an invalid state to an active state according to the sequence number of the plurality of switch circuits; or switching one of the plurality of enable signals from an active state to an invalid state includes switching the enable signal corresponding to the switch circuit with the largest sequence number that is in an active state to an invalid state according to the sequence number of the plurality of switch circuits.

[0030] Optionally, if the first threshold signal is greater than the second threshold signal, and the sampling current is greater than the second threshold signal but less than the first threshold signal, the effective state of any of the plurality of enable signals is not changed.

[0031] Optionally, the enable signal of the first switching circuit is always in an active state.

[0032] Optionally, when the error amplification signal related to the output voltage is greater than the third threshold signal, all of the plurality of enable signals are switched to the active state.

[0033] Optionally, the error amplification signal is generated based on the comparison result between the reference voltage and the feedback signal characterizing the output voltage.

[0034] In the control circuit of the multiphase power conversion circuit provided in this application, an analog-to-digital converter (ADC) is used to sample the inductor current, resulting in higher accuracy. Even if the multiphase power supply includes a 16-phase switching circuit, the ADC can accurately distinguish minute current changes during phase switching. Furthermore, since the ADC is used for sampling, the filter duration can be easily adjusted to set a suitable average sampling duration. Therefore, when the second and third comparators use hysteresis comparators, their upper and lower threshold signals can be easily determined. Consequently, the multiphase power supply and the control circuit of the multiphase power conversion circuit provided in this application have better stability.

[0035] Optionally, after each sampling by the analog-to-digital converter, the second and third comparators update their output states, thus giving the phase control circuit a better real-time response to changes in inductor current.

[0036] Optionally, the phase control circuit also uses a fourth comparator to generate a set signal based on the comparison result of the error amplification signal and the third threshold signal, so that the enable unit sets all enable signals to the active state. When the current of the multiphase power supply suddenly increases in a short period of time, this voltage loop control method using analog signals can quickly wake up the multiphase power supply and has better transient response.

[0037] Optionally, the value of the third threshold signal is set to be slightly greater than one-quarter of the full-load current of the multiphase power supply, so as to ensure that the fourth comparator will generate a set signal only when the current of the multiphase power supply suddenly increases, thereby turning on all the switching circuits to wake up the multiphase power supply. In other cases, a high-precision analog-to-digital converter, the second comparator and the third comparator are used to generate phase-increasing or phase-decreasing signals to control the number of switching circuits in the multiphase power supply in the on state. Attached Figure Description

[0038] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0039] Figure 1 A schematic circuit diagram of a multiphase power supply according to the prior art is shown;

[0040] Figure 2 A schematic circuit diagram of a multiphase power supply according to an embodiment of the present invention is shown;

[0041] Figure 3 It shows Figure 2 Circuit diagram of the PWM controller;

[0042] Figure 4 It shows Figure 2 Circuit structure diagram of the feedback control circuit;

[0043] Figure 5 A flowchart illustrating the operation of a multiphase power supply according to an embodiment of the present invention is shown. Detailed Implementation

[0044] Various embodiments of the invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements or modules are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0045] It should be understood that, in the following description, "circuit" may include single or combined hardware circuits, programmable circuits, state machine circuits, and / or elements capable of storing instructions executed by the programmable circuit. When an element or circuit is said to be "connected" to another element or "connected" between two nodes, it may be directly coupled or connected to the other element, or there may be intermediate elements; the connection between elements may 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 are no intermediate elements between them.

[0046] Furthermore, certain terms are used in this patent specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This patent specification and claims do not distinguish components based on differences in name, but rather on differences in function.

[0047] In this application, the switching transistor is a transistor operating in switching mode to provide a current path, including a bipolar transistor or a field-effect transistor. The first and second terminals of the switching transistor are respectively the high-potential terminal and the low-potential terminal on the current path, and the control terminal is used to receive a drive signal to control the switching transistor's on and off states. A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) includes a first terminal, a second terminal, and a control terminal. In the MOSFET's on state, current flows from the first terminal to the second terminal. For a P-type MOSFET, the first terminal, second terminal, and control terminal are the source, drain, and gate, respectively; for an N-type MOSFET, the first terminal, second terminal, and control terminal are the drain, source, and gate, respectively.

[0048] Furthermore, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] This invention can be presented in various forms, some of which will be described below.

[0050] Figure 2 A schematic circuit diagram of a multiphase power supply according to an embodiment of the present invention is shown. In this application, a multiphase power supply with peak current control mode is used as an example for illustration. Figure 2 As shown, 200 includes 210, 220, 230, and a multiphase power conversion circuit.

[0051] The multiphase power conversion circuit includes switching circuits 201 to 20n. The multiphase power conversion circuit comprises n switching circuits (n is an integer greater than 1), and the output terminals of these n switching circuits are coupled together to provide an output voltage Vout to power the load. The structure of each switching circuit is similar to... Figure 1 The switching circuits 101-103 in the circuit have the same structure. Taking switching circuit 201 as an example, each phase of the switching circuit includes a driving unit, transistor T1, transistor T2, inductor Ls, resistor R4, and capacitor C3. The first terminal of transistor T1 receives the working voltage VIN. The first terminal of transistor T2 is coupled to the second terminal of transistor T1, and the second terminal of transistor T2 is grounded. The first terminal of inductor Ls is coupled to the first terminal of transistor T2, and the second terminal is connected to the first terminal of resistor R4. The first terminal of capacitor C3 is coupled to the second terminal of resistor R4, and the second terminal is grounded. The series-coupled resistor R4 and capacitor C3 form, for example, an output filter circuit.

[0052] The drive unit receives an enable signal ENm (1≤m≤n). When the enable signal ENm is active, the phase switching circuit is in the on state. The drive units in each power conversion circuit 201-20n receive pulse width modulation signals PWM1-PWMn from the multiphase power controller 210, and control the corresponding transistors to turn on and off according to the received pulse width modulation signals. The output voltages of the switching circuits 201-20n are combined into a single output voltage Vout to drive the load RL. When the enable signal ENm is inactive, the drive unit turns off transistors T1 and T2, thereby shutting down the phase switching circuit.

[0053] The multiphase power supply control circuit 210 includes multiple PWM controllers 211-21n, each of which corresponds to a switching circuit 201-20n. Each PWM controller 211-21n determines the operating sequence of the switching circuit 201-20n according to the feedback control signal Vc1 of the feedback control circuit 220, thereby providing the corresponding pulse width modulation signals PWM1-PWMn.

[0054] Specifically, see Figure 3 , Figure 3 It shows Figure 2 The circuit structure diagram of the PWM controller is shown below. Taking PWM controller 211 as an example, PWM controller 211 includes a sampling unit Sample, a first comparator CP1, and an RS flip-flop BM1. The sampling unit Sample samples the inductor current i flowing through the inductor Ls in the switching circuit 201. L1The sampling current IL is obtained, and a current sampling signal is generated based on this sampling current IL. The equivalent resistance of the sampling unit Sample is, for example, Ri, and the value of the current sampling signal is, for example, equal to the sampling current IL (the value of the sampling current IL is, for example, equal to the inductor current i). L1 The product of the current sampling signal and the equivalent resistance Ri. The first negative input of the first comparator CP1 is coupled to the sampling unit Sample to receive the current sampling signal, and the second negative input receives the ripple injection signal Vs to compensate for the ripple of the current sampling signal. Normally, the ripple injection signal Vs is selected from the ramp signal. The positive input of the first comparator CP1 receives the feedback control signal Vc1 provided by the feedback control circuit 220 to generate a reset signal based on the comparison result of the feedback control signal Vc1 and the current sampling signal. The reset terminal R of the RS flip-flop BM1 is coupled to the output terminal of the first comparator CP1 to receive the reset signal, the set terminal S receives the clock signal CLK, and the output terminal Q generates the pulse width modulation signal PWM1 based on the reset signal and the clock signal CLK.

[0055] The feedback control circuit 220 generates a feedback control signal Vc1 based on the feedback signal characterizing the output voltage Vout and the reference voltage signal.

[0056] Specifically, see Figure 4 , Figure 4 It shows Figure 2 The circuit diagram shows the feedback control circuit. The feedback control circuit includes resistors R1 and R2, an error amplifier 221, and a signal processing unit 222. The first terminal of resistor R1 receives the operating voltage Vout, and the first terminal of resistor R2 is coupled to the second terminal of resistor R1, which is grounded. The negative input terminal of the error amplifier 221 is coupled to the first terminal of resistor R2 to receive the feedback signal VFB after the output voltage Vout is divided by resistors R1 and R2. Its positive input terminal receives the reference voltage signal VREF. The error amplifier 221 is adapted to generate an error amplification signal Vc based on the comparison result between the feedback signal VFB and the reference voltage signal VREF.

[0057] The signal processing unit 122 includes capacitors C1 and C2, resistor R3, and amplitude modulation unit k. The first terminal of capacitor C2 is coupled to the output of error amplifier 221, and the second terminal is grounded. The first terminal of resistor R3 is coupled to the first terminal of capacitor C2, and the first terminal of capacitor C1 is coupled to the second terminal of resistor R3, with the second terminal grounded. Capacitor C2, along with the series-coupled resistor R3 and capacitor C1, filters the error amplification signal Vc. Amplification unit k is coupled to the first terminal of resistor R3, receives the error amplification signal Vc, and performs amplitude modulation on it to generate a feedback signal Vc1.

[0058] Continue to refer to Figure 2The phase control circuit 230 adjusts the effective states of multiple enable signals EN1-ENn based on the sampling current IL flowing through it, thereby controlling the opening or closing of the corresponding switching circuits. The sampling current IL is related to the inductor current i of the inductor Ls in the switching circuit 201. L1 The phase control circuit 230 includes an analog-to-digital converter 231, a second comparator 232, a third comparator 233, a fourth comparator 234, and an enable unit 235. The analog-to-digital converter 231 receives the sampled current IL and converts it into a corresponding first intermediate signal. The positive input of the second comparator 232 receives a second threshold signal ILL, and the negative input receives the first intermediate signal. When the first intermediate signal is less than the second threshold signal ILL, the second comparator 232 generates a decrement signal indicating an active state. The positive input of the third comparator 233 receives the first intermediate signal, and the negative input receives the first threshold signal ILH. When the first intermediate signal is greater than the first threshold signal ILH, the third comparator 233 generates an increment signal indicating an active state. When the enable unit 235 receives an increment signal indicating an active state, it switches an invalid enable signal to an active state; when it receives a decrement signal indicating an active state, it switches an active enable signal to an invalid state.

[0059] This application uses an analog-to-digital converter 231 to control the inductor current i L1 Sampling offers higher accuracy; even with a multiphase power supply including a 16-phase switching circuit, the analog-to-digital converter 231 can accurately distinguish minute current changes during phase conversion. Furthermore, because sampling is performed using the analog-to-digital converter 231, the filter duration can be easily adjusted to set a suitable average sampling duration. Therefore, when the second comparator 232 and the third comparator 233 employ hysteresis comparators, their upper and lower threshold signals can be easily determined. Consequently, the control circuit of the multiphase power supply and multiphase power conversion circuit provided in this application exhibits better stability.

[0060] In this embodiment, based on the sequence number of multiple switching circuits, phase increments are performed in ascending order, and phase decrements are performed in descending order. For example, if enable signals EN1 to EN5 are currently active, and the remaining enable signals are inactive, then when enable unit 235 receives an active phase increment signal, enable signal EN6 switches from inactive to active. If it receives another active phase increment signal, enable signal EN7 switches from inactive to active. After each sampling by analog-to-digital converter 231, the second comparator 232 and the third comparator 233 update their output states. Therefore, the phase number control circuit controls the inductor current i. L1The changes have better real-time response capability. At the same time, in order to ensure that the analog-to-digital converter 231 maintains an effective output, the switching circuit coupled to the analog-to-digital converter 231 remains in the on state, that is, the enable signal of the switching circuit is always in the effective state. Normally, the first phase is selected, that is, the switching circuit 201 is coupled to the analog-to-digital converter 231, but it should be understood that other switching circuits can also be selected.

[0061] The fourth comparator 234 is selected from a hysteresis comparator, for example. Its positive input terminal receives the error amplification signal Vc, and its negative input terminal receives the third threshold signal VH. When the current of the multiphase power supply 200 suddenly increases in a short period of time, for example, when switching from a low power state to a full load state, the error amplification signal Vc is greater than the third threshold signal VH. The fourth comparator 234 generates a set signal for the valid state. When the enable unit 235 receives the set signal for the valid state, it sets the enable signals EN1-ENn to the valid state, turns on the switching circuits 201-20n, and thus wakes up the multiphase power supply 200.

[0062] When the current of the multiphase power supply 200 suddenly increases in a short period of time, the voltage loop of the analog signal is used for control, and all the switching circuits 201-20n are turned on, which has a better transient response when the multiphase power supply 200 is woken up.

[0063] Optionally, in this embodiment, the value of the third threshold signal VH is set to be slightly greater than one-quarter of the full-load current of the multiphase power supply 200, thereby ensuring that the fourth comparator 234 will only generate a set signal when the current of the multiphase power supply 200 suddenly increases, thus turning on all the switching circuits to wake up the multiphase power supply. In other cases, the high-precision analog-to-digital converter 231, the second comparator 232 and the third comparator 233 are still used to generate an increasing or decreasing phase signal to control the number of switching circuits in the multiphase power supply 200 in the on state.

[0064] It should be understood that in this embodiment, the second comparator 232, the third comparator 233, and the enable unit 235 are selected from digital logic circuits, and their functions are implemented through digital design. The first threshold signal ILH and the second threshold signal ILL are also stored in digital form. The fourth comparator 234 is selected from analog circuits. Therefore, the phase number control circuit 230 provided in this application combines the high accuracy of digital logic circuits with the good transient response of analog circuits.

[0065] Optionally, Figure 5 A flowchart illustrating the operation of a multiphase power supply according to an embodiment of the present invention is shown, in conjunction with... Figures 2 to 4 The workflow of the various power supplies 200 in the embodiments of this application will be further described. Among them, Figure 5 The logical operations shown are mainly composed of Figure 2 Enable unit 235 is completed.

[0066] In step S0, the multiphase power supply 200 is started, and the number of phases in the on state is n. That is, the enable signals EN1-ENn generated by the phase number control circuit 230 are all in the valid state, and the number of switching circuits in the on state is n.

[0067] In step S1, the multiphase power supply 200 is started up, and the number of phases in the on state is n. Under normal external conditions, such as no change in load, the voltage, current and other signals of the multiphase power supply 200 tend to stabilize, and the multiphase power supply 200 is started up.

[0068] When the sampled current IL is less than the second threshold signal ILL, the second comparator 232 generates a phase-decrease signal of the valid state based on the comparison result of the sampled current IL and the second threshold signal. After receiving the phase-decrease signal of the valid state, the enable unit 235 switches an enable signal that is in the valid state to the invalid state to turn off a switching circuit, thereby improving the overall working efficiency of the multiphase power supply 200.

[0069] When the sampled current IL is greater than the first threshold signal ILH, the third comparator 233 generates an active phase-increasing signal based on the comparison result between the sampled current IL and the first threshold signal. After receiving the active phase-increasing signal, the enable unit 235 switches an invalid enable signal to an active state to start a switching circuit, thereby meeting the load RL's requirement for the multiphase power supply 200's output current.

[0070] When the number of phases of the multiphase power supply 200 in the on state is not n, if the error amplification signal Vc is greater than the third threshold signal VH, it indicates that the current of the multiphase power supply 200 suddenly increases. The fourth comparator 234 generates a set signal for the effective state based on the error amplification signal Vc and the third threshold signal VH. After receiving the set signal for the effective state, the enable unit 235 sets the enable signals EN1-ENn to the effective state, turns on the switching circuits 201-20n, and completes the wake-up of the multiphase power supply 200.

[0071] In summary, the control circuit of the multiphase power conversion circuit provided in this application uses an analog-to-digital converter 231 to control the inductor current i L1 Sampling offers higher accuracy; even with a multiphase power supply including a 16-phase switching circuit, the analog-to-digital converter 231 can accurately distinguish minute current changes during phase conversion. Furthermore, because sampling is performed using the analog-to-digital converter 231, the filter duration can be easily adjusted to set a suitable average sampling duration. Therefore, when the second comparator 232 and the third comparator 233 employ hysteresis comparators, their upper and lower threshold signals can be easily determined. Consequently, the control circuit of the multiphase power supply and multiphase power conversion circuit provided in this application exhibits better stability.

[0072] Optionally, after each sampling by the analog-to-digital converter 231, the second comparator 232 and the third comparator 233 update their output states, thus the phase number control circuit controls the inductor current i. L1 It has better real-time response capabilities to changes.

[0073] Optionally, the phase control circuit also uses a fourth comparator 234 to generate a set signal based on the comparison result of the error amplification signal Vc and the third threshold signal VH, so that the enable unit 235 sets the enable signals EN1-ENn to the active state. When the current of the multiphase power supply 200 suddenly increases in a short time, this voltage loop control method using analog signals can quickly wake up the multiphase power supply 200 and has better transient response.

[0074] Optionally, the value of the third threshold signal VH is set to be slightly greater than one-quarter of the full-load current of the multiphase power supply 200, thereby ensuring that the fourth comparator 234 will generate a set signal only when the current of the multiphase power supply 200 suddenly increases, turning on all the switching circuits to wake up the multiphase power supply. In other cases, the high-precision analog-to-digital converter 231, the second comparator 232 and the third comparator 233 are used to generate phase-increasing or phase-decreasing signals to control the number of switching circuits in the multiphase power supply 200 in the on state.

[0075] It should be noted that those skilled in the art will understand that the terms “during,” “when,” and “when…” used herein in relation to circuit operation are not strict terms indicating an action that occurs immediately upon the commencement of a startup action, but rather that there may be some small but reasonable delays, such as various propagation delays, between the startup action and the reaction action initiated by it. The terms “approximately” or “substantially” used herein mean that an element value is expected to be close to the declared value or position. However, as is well known in the art, there are always small deviations that make it difficult for the value or position to be strictly the declared value. It has been properly determined in the art that a deviation of at least ten percent (10%) (or at least twenty percent (20%) for semiconductor doping concentration) is a reasonable deviation from the described accurate ideal target. When used in conjunction with signal states, the actual voltage value or logic state of the signal (e.g., “1” or “0”) depends on whether positive or negative logic is used.

[0076] As described above, these embodiments of the present invention do not exhaustively describe all details, nor do they limit the invention to specific embodiments. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. The scope of protection of this invention should be determined by the scope defined in the claims and their equivalents.

Claims

1. A control circuit for a multiphase power conversion circuit, the multiphase power conversion circuit comprising multiple switching circuits, the output terminals of the multiple switching circuits being coupled together to provide an output voltage to power a load, the control circuit comprising: The feedback control circuit generates a feedback control signal based on the feedback signal characterizing the output voltage and the reference voltage signal; The multiphase power supply control circuit includes multiple PWM controllers that correspond one-to-one with the multiple switching circuits. Each PWM controller provides a pulse width modulation signal based on the feedback control signal and the current sampling signal of the corresponding switching circuit. The phase control circuit is adapted to adjust the effective state of each of a plurality of enable signals according to a sampled current characterizing the inductor current in the first switching circuit among the plurality of switching circuits, so as to control the corresponding switching circuit to operate in an on state or in an off state, wherein the plurality of enable signals correspond one-to-one with the plurality of switching circuits. The phase number control circuit includes: The analog-to-digital conversion unit receives the sampled current from the first switching circuit and generates a first intermediate signal based on the sampled current. The second comparator is adapted to compare the second threshold signal with the first intermediate signal and generate a subtractive phase signal based on the comparison result; A third comparator is adapted to compare the first threshold signal with the first intermediate signal and generate an increasing phase signal based on the comparison result; The enabling unit changes the number of enabled signals in the valid state among the multiple enabled signals it generates based on the valid state of the received phase-increasing signal and / or phase-decreasing signal. When it receives a valid phase-increasing signal, it switches an invalid enabled signal to the valid state; when it receives a valid phase-decreasing signal, it switches an valid enabled signal to the invalid state.

2. The control circuit according to claim 1, wherein, The phase control circuit is configured such that when the sampling current of the first switching circuit is greater than the first threshold signal, the third comparator generates an increasing phase signal in an effective state. When the sampling current of the first switching circuit is less than the second threshold signal, the second comparator generates a subtracted phase signal indicating an effective state.

3. The control circuit according to claim 2, wherein, Switching an invalid enable signal to an valid state includes, according to the sequence number of the plurality of switching circuits, the enable unit switches the enable signal corresponding to the switching circuit with the smallest sequence number that is currently invalid to a valid state; or The step of switching an active enable signal to an inactive state includes, according to the sequence number of the plurality of switch circuits, the enable unit switches the enable signal corresponding to the switch circuit with the largest sequence number that is active to an inactive state.

4. The control circuit according to claim 3, wherein, The first threshold signal is greater than the second threshold signal. When the sampling current of the first switching circuit is greater than the second threshold signal and less than the first threshold signal, the enabling unit does not change the effective state of any of the plurality of enabling signals.

5. The control circuit according to claim 1, wherein, The feedback control circuit includes: An error amplifier is suitable for comparing the feedback signal of the output voltage with a reference voltage signal and generating an error amplification signal based on the comparison result. The signal processing unit is adapted to filter and / or amplitude modulate the error amplification signal to generate the feedback control signal.

6. The control circuit according to claim 5, wherein the feedback control circuit further comprises: A first resistor and a second resistor are connected in series between the output voltage and ground, and the intermediate node between the first resistor and the second resistor provides the feedback signal.

7. The control circuit according to claim 5, wherein, The signal processing unit includes: A second capacitor is coupled between the output terminal of the error amplifier and ground; A third resistor and a first capacitor are connected in series between the output of the error amplifier and ground; and An amplitude modulation unit is configured to perform amplitude modulation processing on the error amplification signal to generate the feedback control signal.

8. The control circuit according to claim 5, wherein the phase number control circuit is further configured to switch all enable signals to an active state when the error amplification signal is greater than the third threshold signal.

9. The control circuit according to claim 8, wherein, The third threshold signal is slightly greater than a quarter of the full-load current.

10. The control circuit according to claim 9, wherein, The phase number control circuit further includes a fourth comparator, adapted to compare the error amplification signal with the third threshold signal and generate a set signal; When the enabling unit receives the set signal indicating an effective state, it sets all of the plurality of enabling signals it provides to an effective state.

11. The control circuit according to claim 10, wherein, The second, third, and fourth comparators are selected from Schmitt triggers.

12. The control circuit according to claim 1, wherein, The PWM controller includes: The sampling unit is adapted to generate the current sampling signal based on the sampling current flowing through the inductor in the switching circuit; The first comparator receives a current sampling signal at its positive input terminal and the feedback control signal at its first negative input terminal, and generates a reset signal based on the comparison result between the current sampling signal and the feedback control signal. The first flip-flop has a reset terminal coupled to the output terminal of the first comparator to receive the reset signal, a set terminal to receive a clock signal, and an output terminal to provide the pulse width modulation signal according to the reset signal and the clock signal.

13. The control circuit according to claim 12, wherein the first comparator further includes a second negative input terminal for receiving a ripple injection signal to perform ripple compensation on the current sampling signal.

14. The control circuit according to claim 1, wherein when at least one of the plurality of switching circuits is in the on state, the enable signal of the first switching circuit is always in the valid state.

15. The control circuit according to claim 10, wherein, The second comparator, the third comparator, and the enable unit are selected from digital logic circuits, and the fourth comparator is selected from analog circuits.

16. A multiphase power supply, comprising: A multiphase power conversion circuit includes multiple switching circuits, the output terminals of which are coupled together to supply power to the load. as well as The control circuit as described in any one of claims 1 to 15.

17. The multiphase power supply according to claim 16, wherein the switching circuit comprises: The main switching transistor is suitable for controlling the transfer of electrical energy from the input terminal to the output terminal; The driving unit is configured to control the conduction state of the main switch transistor according to a pulse width modulation signal, thereby generating the output voltage according to the input voltage; wherein, The drive unit is also configured to turn the main switch on or off based on the valid state of the enable signal.

18. The multiphase power supply according to claim 17, wherein, The drive unit is configured as follows: When the enable signal is active, the main switch is turned on and off according to the pulse width modulation signal. When the enable signal is in an invalid state, the main switch is turned off.

19. A control method for a multiphase power circuit, the multiphase power circuit comprising a plurality of switching circuits, the output terminals of the plurality of switching circuits being coupled together to provide an output voltage to supply power to a load, the control method comprising: The inductor current of the first switching circuit among the plurality of switching circuits is sampled to obtain the sampling current; After the sampled current is converted into a digital signal, it is compared with the first threshold signal and the second threshold signal respectively. Based on the comparison result, the effective state of multiple enable signals corresponding to the multiple switching circuits is controlled, thereby controlling the corresponding switching circuits to operate in the on or off state. Specifically, when the sampling current is greater than the first threshold signal, one of the plurality of enable signals that is in an invalid state is switched to an active state; when the sampling current is less than the second threshold signal, one of the plurality of enable signals that is in an active state is switched to an invalid state.

20. The control method according to claim 19, wherein, The step of switching one of the plurality of enable signals from an invalid state to an effective state includes switching the enable signal corresponding to the switch circuit with the smallest sequence number that is in an invalid state to an effective state according to the sequence number of the plurality of switch circuits. or The step of switching one of the multiple enable signals from an active state to an inactive state includes switching the enable signal corresponding to the switch circuit with the largest enable signal from an active state to an inactive state, according to the sequence number of the multiple switch circuits.

21. The control method according to claim 20, wherein, The first threshold signal is greater than the second threshold signal. When the sampling current is greater than the second threshold signal and less than the first threshold signal, the effective state of any of the plurality of enable signals is not changed.

22. The control method according to claim 19, wherein, The enable signal of the first switching circuit is always in an active state.

23. The control method according to claim 19, further comprising: When the error amplification signal related to the output voltage is greater than the third threshold signal, all of the multiple enable signals are switched to the active state.

24. The control method according to claim 23, wherein, The error amplification signal is generated based on the comparison between the reference voltage and the feedback signal characterizing the output voltage.

Images