Power supply controller for switching power supply system and switching power supply system

Abstract

The application provides a power supply controller and a switching power supply system. The power supply controller comprises: a first input end connected with an output end of an inductive energy storage element of the switching power supply system; an output branch for outputting an output voltage signal; a feedback unit for generating a feedback signal one-to-one according to the output voltage signal; a second input end for obtaining a current sampling voltage signal of an input voltage signal of the switching power supply system; a modulation control unit for outputting a modulation control signal according to the feedback signal, a reference voltage signal and the current sampling voltage signal; a driving unit for outputting a driving signal under the control of the modulation control signal, the driving signal being used for controlling the on-off of a power switch of the switching power supply system; and a balance control unit for generating a control signal one-to-one according to the feedback signal, the control signal being used for one-to-one control of the output branch in turn and time-division conduction.

Description

Technical Field

[0001] This application relates primarily to the field of switching power supply technology, and more particularly to a power controller and a switching power supply system for use in switching power supply systems. Background Technology

[0002] Switching power supplies are widely used in power electronics due to their high efficiency and high power density. Depending on the type of input power supply, their applications can be divided into two main categories: First, in AC-powered electronic devices (such as household appliances, mobile phone chargers, and server power supplies), the AC input voltage needs to be converted to a low-voltage DC voltage to power the electronic devices. Second, in new energy fields such as photovoltaic power generation, energy storage systems, and electric vehicles, the DC input voltage needs to be converted to DC output voltages of different voltage levels. In these applications, different functional modules within the electronic devices often require multiple power supplies of different voltage levels. For example, microcontroller units (MCUs) typically require a 3V to 5V supply voltage, relay drive circuits typically require a 12V supply voltage, and the pre-drive circuit of power modules typically requires a 15V supply voltage. Therefore, switching power supplies need to have multi-output capabilities to simultaneously meet the power supply requirements of different loads.

[0003] In existing technologies, a common approach to achieving multiple outputs is to use a transformer with multiple secondary windings, each secondary winding corresponding to one output voltage, and cascading DC-DC converters or low-dropout linear regulators (LDOs) on some output branches for voltage regulation. However, this approach has the following drawbacks: Firstly, regarding cross-regulation, in multi-output systems, typically only one output is selected as the closed-loop feedback control object, while the voltages of the remaining outputs passively follow the output of that feedback path, depending on the transformer winding turns ratio. When the load on the feedback path changes, the coupling energy between the primary and secondary sides of the transformer changes accordingly, causing deviations in the output voltage of the non-feedback paths, resulting in a poor load cross-regulation. This problem is particularly pronounced when the load currents of each path differ significantly, making it difficult to guarantee the accuracy of each output voltage.

[0004] Secondly, when using an LDO, the voltage drop loss is relatively large, especially in applications with high output current, significantly increasing the heat dissipation pressure and affecting the thermal reliability of the system. While using a DC-DC converter offers relatively high efficiency, it requires additional magnetic components such as power inductors, and the higher switching frequency introduces additional electromagnetic interference (EMI), increasing the design complexity of the filter circuit.

[0005] Third, at the system-wide level, the multi-winding transformer design and cascaded voltage regulation devices together result in a large number of components required by the system, increasing the complexity of the circuit topology, which in turn increases the design difficulty and system cost, hindering the miniaturization and integration of power supply systems. Summary of the Invention

[0006] This application addresses the aforementioned technical problems by providing a power controller and a switching power supply system for use in switching power supply systems. This improves the dynamic response and cross-regulation performance of the switching power supply system and saves on components and reduces costs.

[0007] To address the aforementioned technical problems, this application provides a power controller for a switching power supply system, used to output n output voltage signals based on a single input voltage signal, comprising: a first input terminal for connection to the output terminal of an inductive energy storage element of the switching power supply system; n output branches, each output branch connected to the first input terminal for outputting one output voltage signal, where n is a positive integer greater than or equal to 2; a feedback unit for generating n feedback signals corresponding to the n output voltage signals; a second input terminal for connection to the inductive energy storage element of the switching power supply system to obtain a current sampling voltage signal of the input voltage signal of the switching power supply system; a modulation control unit for outputting a modulation control signal based on at least one of the n feedback signals, a reference voltage signal, and the current sampling voltage signal; a drive unit for outputting a drive signal under the control of the modulation control signal, the drive signal being used to control the power switch of the switching power supply system to turn on and off; and an equalization control unit for generating n control signals corresponding to the n feedback signals, the n control signals being used to control the n output branches to turn on sequentially in a time-division manner.

[0008] In one embodiment of this application, a first control circuit and a second control circuit are included. The first control circuit includes the modulation control unit, the driving unit, and the feedback unit. The first control circuit is used to form a first loop with the inductive energy storage element and the power switch of the switching power supply system. The second control circuit includes the n output branches, the feedback unit, and the equalization control unit. The second control circuit is used to form a second loop with the inductive energy storage element. The first loop and the second loop are decoupled from each other.

[0009] In one embodiment of this application, the feedback signal is obtained by voltage division of the corresponding output voltage signal, wherein the ratio of the output voltage signal to the feedback signal is equal to the ratio of the preset voltage value to the reference voltage signal; wherein the first loop is further configured to cause the n output voltage signals to converge to a fixed preset voltage value, and the second loop is further configured to ensure that when converged to a steady state, the ratio between each output voltage signal and the corresponding preset voltage value is the same.

[0010] In one embodiment of this application, the equalization control unit includes n-1 cascaded loop gain units, wherein the j-th loop gain unit is used to generate a j-th control signal based on the j-th feedback signal and the (j+1)-th feedback signal, where j is a positive integer from 1 to n-1.

[0011] In one embodiment of this application, the equalization control unit further includes a logic unit, which is used to perform logical operations based on the first to (n-1)th control signals and control pulses to obtain the nth control signal, wherein the control pulses encompass the entire demagnetization phase of the inductive energy storage element of the switching power supply system within one switching cycle of the power switch.

[0012] In one embodiment of this application, among the first to nth control signals, when the first control signal of two adjacent control signals switches from the on level to the off level, the second control signal switches from the off level to the on level, wherein the nth control signal switches to the off level after the demagnetization stage ends.

[0013] In one embodiment of this application, the equalization control unit further includes a switching element, which is used to switch the nth output branch from the off state to the on state when the (n-1)th control signal switches from the on level to the off level, and switches to the off state after the demagnetization phase of the inductive energy storage element of the switching power supply system ends.

[0014] In one embodiment of this application, the modulation control unit is a PWM control unit, the modulation control signal is a PWM signal, and the PWM control unit includes an energy adjustment unit, a trigger, and a comparator. The energy adjustment unit is used to generate a threshold voltage signal and a set signal based on at least one feedback signal and a reference voltage signal. The set signal and the threshold voltage signal, along with a reset signal generated by the comparator from the current sampling voltage signal, are input to the trigger to generate the PWM signal. The set signal is used to determine the frequency of the PWM signal, and the threshold voltage signal, together with the current sampling voltage signal, is used to determine the pulse width of the PWM signal.

[0015] In one embodiment of this application, the energy regulation unit includes n comparators and OR gates. The n feedback signals are respectively input to the n comparators. Each comparator is used to compare the corresponding feedback signal and the reference voltage signal and generate a comparison result. The n comparison results are input to the OR gate to obtain the set signal.

[0016] In one embodiment of this application, the energy regulation unit includes a weighted comparator and n weighted current generating modules. The j-th weighted current generating module is used to generate a weighted current positively correlated with the load size corresponding to the j-th output branch under the control of the j-th control signal. The load is the load connected to the second terminal of the output branch in the switching power supply system. The weighted comparator includes n differential pairs and a current mirror. The inputs of the j-th differential pair are the j-th feedback signal and the reference voltage signal, respectively. The output terminals of the n differential pairs are connected to the input terminal of the current mirror so that the output currents of each differential pair are superimposed at the input terminal of the current mirror to form a weighted error signal. The weighted error signal is used as the set signal, where j is a positive integer from 1 to n-1.

[0017] In one embodiment of this application, the weighted comparator further includes a weighted amplifier, which is used to amplify the weighted error signal, and the amplified weighted error signal is used as the set signal.

[0018] In one embodiment of this application, the energy adjustment unit includes: a weighted summation unit for weighted summation of at least one of the feedback signals and outputting a weighted summation signal; an operational amplifier including a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal is used to receive the weighted summation signal, the second input terminal is used to receive the reference voltage signal, the operational amplifier is used to amplify the difference between the weighted summation signal and the reference voltage signal, and outputs an error amplification signal at the output terminal; a compensation network coupled to the output terminal of the operational amplifier for frequency compensation of the error amplification signal to stabilize the loop; and a frequency generation unit coupled to the output terminal of the operational amplifier. The system includes a set signal with a first frequency based on the error amplification signal; a threshold generation unit coupled to the output of the operational amplifier, used to generate the threshold voltage signal based on the error amplification signal; and a comparator including a first comparator input, a second comparator input, and a comparator output. The first comparator input is used to receive the current sampling voltage signal of the input signal of the switching power supply system, and the second comparator input is coupled to the output of the threshold generation unit to receive the threshold voltage signal. The comparator is used to output a reset signal through the output when the current sampling voltage signal is greater than the threshold voltage signal, and the reset signal is used to input to the trigger.

[0019] In one embodiment of this application, the modulation control unit is a PFM control unit, the modulation control signal is a PFM signal, and the driving unit is an isolated driving unit. The switching power supply system includes a transformer, the primary winding and the secondary winding of the transformer are not grounded, the primary winding corresponds to the primary ground, the secondary winding corresponds to the secondary ground, the reference ground of the PFM signal is the secondary ground, the PFM signal is coupled to the primary winding through the isolated driving unit to generate the driving signal, and the reference ground of the driving signal is the primary ground.

[0020] To address the aforementioned technical problems, this application also proposes a switching power supply system, comprising: a power controller as described above; an inductive energy storage element, including a transformer, the transformer comprising a primary winding and a secondary winding, the first end of the primary winding being used to receive an input voltage signal, the first end of the secondary winding being connected to the first input terminal of the power controller, and the second end of the secondary winding being grounded; a power switch, the first end of the power switch being connected to the second end of the primary winding, the second end of the power switch being grounded through a current sampling resistor and connected to the second input terminal of the power controller, the control terminal of the power switch being used to receive the drive signal; n output loads, each correspondingly connected to the second end of the n output branches; and n output capacitors, each correspondingly connected in parallel with the n output loads.

[0021] To address the aforementioned technical problems, this application also proposes a switching power supply system, comprising: a power controller as described above; an inductive energy storage element, including a power inductor, the first end of which is connected to the second input terminal of the power controller, the first end of which is also connected to the first input terminal of the power controller through a current sampling resistor, the second end of which is connected to the negative terminal of a freewheeling diode, and the positive terminal of the freewheeling diode is grounded; a power switch, the second end of which is connected to the second end of the power inductor, the first end of which is used to receive an input voltage signal, and the control terminal of which is used to receive a drive signal; n output loads, each corresponding to one of the second ends of the n output branches; and n output capacitors, each corresponding to one of the n output loads.

[0022] To address the aforementioned technical problems, this application also proposes a switching power supply system, comprising: a power controller as described above; an inductive energy storage element including a power inductor, wherein a first end of the power inductor is connected to a first input terminal of the power controller, and a second end of the power inductor is connected to a second input terminal of the power controller; a first power switch, wherein a second end of the first power switch is connected to a second end of the power inductor and to a second input terminal of the power controller, the first end of the first power switch being used to receive an input voltage signal, and a control terminal of the first power switch being used to receive a drive signal; a second power switch, wherein a first end of the second power switch is connected to a second end of the power inductor, the second end of the second power switch being grounded, and a control terminal of the second power switch being connected to a synchronous output terminal of the power controller, the synchronous output terminal being used to output a synchronous control signal to enable the second power switch to conduct during the freewheeling phase of the power inductor; n output loads, each correspondingly connected to the second end of the n output branches; and n output capacitors, each correspondingly connected in parallel with the n output loads.

[0023] When the power controller of this application is applied to a switching power supply system, the modulation control unit, drive unit, feedback unit, inductive energy storage element, and power switch in the switching power supply system form a first loop, and the n output branches, feedback unit, equalization control unit, and inductive energy storage element form a second loop. The control variable generated by the first loop is the modulation control signal, and the control variable generated by the second loop is the control signal. The two are unrelated. The first loop and the second loop are decoupled from each other and there is no cross-control between them. This can greatly improve the cross-regulation rate and loop stability of the switching power supply system. Furthermore, it eliminates the need for components such as LDOs, simplifying the circuit design and reducing costs. Attached Figure Description

[0024] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application. In the drawings: Figure 1 This is a circuit diagram of a flyback auxiliary power supply system used in the outdoor unit of an air conditioner. Figure 2 This is an exemplary circuit diagram of a switching power supply system, including a switching power supply controller according to an embodiment of this application. Figure 3 This is a schematic diagram of the first loop formed when the switching power supply controller of one embodiment of this application is used in a switching power supply system; Figure 4 This is a schematic diagram of the second loop formed when the switching power supply controller of one embodiment of this application is used in a switching power supply system; Figure 5 This is a circuit diagram of the equalization control unit in a power controller according to an embodiment of this application; Figure 6 yes Figure 5 The waveform diagram corresponding to the equalization control unit is shown below; Figure 7 This is a functional block diagram of a loop gain unit implemented using an analog PI unit. Figure 8 This is a functional block diagram of a discrete control PI unit; Figure 9 This is a waveform diagram of the second loop formed by the power controller according to an embodiment of this application; Figure 10 This is a dynamic adjustment waveform diagram of the second loop formed by the power controller according to an embodiment of this application; Figure 11 This is a circuit diagram of a switching power supply system including three outputs according to an embodiment of this application; Figure 12 yes Figure 11 The diagram shown is a functional block diagram of the equalization control unit of the three-output power controller. Figure 13 Is with Figure 12 The circuit diagram corresponding to the functional block diagram; Figure 14 This is a circuit diagram of the modulation control unit in a power controller according to an embodiment of this application; Figure 15 yes Figure 14 Dynamic waveform diagram of the modulation control unit in the embodiment shown; Figure 16 This is a circuit diagram of the modulation control unit in a power controller according to another embodiment of this application; Figure 17 This is a block diagram of the modulation control unit in a power controller according to another embodiment of this application; Figure 18 Based on Figure 11 Simulation results of the three-output switching power supply system of the illustrated embodiment; Figure 19 This is a circuit diagram of a three-output switching power supply system according to an embodiment of this application; Figure 20 This is a block diagram of a switching power supply system according to another embodiment of this application; Figure 21 This is a block diagram of a switching power supply system according to another embodiment of this application. Detailed Implementation

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0026] As indicated in this application, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. It should be understood that when a component is referred to as "on another component," "connected to another component," "coupled to another component," or "in contact with another component," it may be directly on, connected to, coupled to, or in contact with that other component, or there may be an inserting component. In contrast, when a component is referred to as "directly on another component," "directly connected to," "directly coupled to," or "directly in contact with" another component, there is no inserting component. Similarly, when a first component is referred to as "electrically contacting" or "electrically coupled to" a second component, there is an electrical path between the first and second components that allows current to flow. This electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even if there is no direct contact between the conductive components.

[0027] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0028] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0029] Switching power supply systems typically include flyback switching power supply systems, forward switching power supply systems, buck switching power supply systems, and buck-boost switching power supply systems. The power controller for switching power supply systems described in this application can be applied to various types of switching power supply systems, and is particularly suitable for flyback and buck switching power supply systems.

[0030] Figure 1 This is a circuit diagram of a flyback auxiliary power supply system used in the outdoor unit of an air conditioner. (Example) Figure 1 As shown, the power supply system 100 requires three output voltage branches: 15V, 12V, and 5V, to adapt to different load requirements. However, the power supply system 100 has a complex multi-winding transformer design, resulting in complex circuitry, numerous components, and high design complexity and system cost. Of the three output branches, only the 5V output branch feeds back to the FB terminal of the control chip; the other output branches passively follow this feedback path according to their turns ratio, leading to poor load cross-regulation. The power supply system 100 also includes two LDO modules, resulting in significant losses. To address these issues, this application proposes a single-input multiple-output power controller, also known as SIMO (Single-Input Multiple-Output) or SIMO (Single-Inductor Multiple-Output). This power controller eliminates the need for multiple windings, LDOs, and numerous passive components found in traditional architectures. This power controller can be applied to various types of switching power supply systems, improving system efficiency, increasing output accuracy, reducing cross-regulation, and significantly reducing system cost.

[0031] The following is a brief description of one embodiment of a switching power supply system including a power controller, with reference to the accompanying drawings, followed by a detailed description of a specific embodiment of the power controller.

[0032] Figure 2 This is an exemplary circuit diagram of a switching power supply system, including a power controller according to an embodiment of this application. Figure 2 As shown, the switching power supply system 200 includes a power controller 201, an inductive energy storage element, a power switch M1, and n output loads R. L1 ~R Ln and n output capacitors C L1 ~C Ln Where n is a positive integer greater than or equal to 2. In this embodiment, the inductive energy storage element is a transformer TX. The transformer TX includes a primary winding 221 and a secondary winding 222. The first terminal 2211 of the primary winding 221 is used to receive the input voltage signal Vin. The first terminal 2221 of the secondary winding 222 is connected to the first input terminal FW of the power controller 201, and the second terminal 2222 of the secondary winding 222 is grounded. The power switch M1 includes a first terminal 231, a second terminal 232, and a control terminal 233. In this embodiment, the power switch M1 is a MOSFET. The first terminal 231 is the drain, the second terminal 232 is the source, and the control terminal 233 is the gate. The first terminal 231 is connected to the second terminal 2212 of the primary winding 221. The second terminal 232 is grounded (GND) through a current sampling resistor Rs and is connected to the second input terminal CS of the power controller 201. The control terminal 233 is used to receive the drive signal DR output by the power controller 201. n output loads R L1 ~R Ln Each of the n output branches 2111~211n of the power controller 201 is connected to the second terminals 211b1~211bn in a one-to-one correspondence. The n output capacitors C L1 ~C Ln One-to-one correspondence with n output loads R L1 ~R Ln in parallel.

[0033] exist Figure 2 In the illustrated embodiment, the switching power supply system 200 is a flyback switching power supply system. The transformer TX is a flyback transformer. The input voltage signal Vin of the switching power supply system 200 is a DC voltage or a voltage formed after rectifying an AC voltage. In this embodiment, when the power switch M1 is turned on, the magnetizing inductance of the transformer TX stores energy; when turned off, the energy is released through the secondary winding 222 to the n output branches 2111~211n in a time-division manner. The current sampling resistor Rs is used to collect the charging current of the magnetizing inductance of the transformer TX for current-mode control. The output capacitor C... L1 ~C Ln Used to supply power to the corresponding output load R during the period when the corresponding output branch is not charged. L1 ~R Ln Release the stored energy to maintain the stability of the output voltage of this circuit.

[0034] In some embodiments, the switching power supply system 200 further includes a DC voltage source 211 for providing an input voltage signal Vin.

[0035] The following is a detailed description of the power controller 201.

[0036] exist Figure 2 In the illustrated embodiment, the power controller 201 includes a first input terminal FW, n output branches 2111~211n, a feedback unit 310, a modulation control unit 320, a second input terminal CS, a drive unit 330, and an equalization control unit 340. The first input terminal FW is connected to the output terminal of the inductive energy storage element of the switching power supply system 200. In this embodiment, the output terminal of the inductive energy storage element is the first terminal 2221 of the secondary winding 222 of the transformer TX. In the n output branches 2111~211n, the first terminal 211a of each output branch 2111~211n is connected to the first input terminal FW. Each output branch 2111~211n is used to output an output voltage signal Vo1~Vo1 from its second terminal 211b1~211bn. n Where n is a positive integer greater than or equal to 2. In some embodiments, each output voltage signal Vo1~Vo n They are all different, and their output targets are each equal to a preset output voltage value. The preset output voltage value is, for example,... Figure 1 The power supply system 100 shown has 15V, 12V, and 5V. Specific values ​​depend on the application scenario and are not limited in this application. In this embodiment, the first terminal 211a of each output branch 2111~211n is connected to the first input terminal FW, hence a single label is used. The feedback unit 310 is used to adjust the n output voltage signals Vo1~Vo n n feedback signals V are generated in a one-to-one correspondence. FB1 ~V FBn In this embodiment, the feedback signal V FB1 ~V FBn It is a voltage signal. For example... Figure 2 As shown, n-channel feedback signals V FB1 ~V FBn On one hand, it outputs to the modulation control unit 320, and on the other hand, it also outputs to the equalization control unit 340. The second input terminal CS is used to connect to the inductive energy storage element of the switching power supply system 200 to obtain the current sampling voltage signal V of the input voltage signal Vin of the switching power supply system 200. CS The modulation control unit 320 is used to adjust the input based on the n-channel feedback signals V. FB1 ~V FBn At least one of the following: a reference voltage signal Vref and a current sampling voltage signal V. CSOutput modulation control signal. In this embodiment, the modulation control unit 320 is specifically a PWM (Pulse Width Modulation) control unit, and the modulation control signal is a PWM signal. In this embodiment, the second input terminal CS is also the CS port of the modulation control unit 320. The drive unit 330 is used to output a drive signal DR under the control of the modulation control signal. The drive signal DR is used to control the on and off of the power switch M1 of the switching power supply system 200. The equalization control unit 340 is used to adjust the output based on the n feedback signals V. FB1 ~V FBn n control signals Ts1~Ts are generated in a one-to-one correspondence. n The n control signals Ts1~Ts n This is used to control the n output branches 2111~211n to be turned on sequentially in a time-division manner, so that the n output branches 2111~211n can obtain energy from the inductive energy storage element in a time-division manner. This application does not impose any restrictions on how the output branches 2111~211n are turned on. Figure 2 In the illustrated embodiment, each output branch 2111~211n is equipped with a switch S1~S2. n It can be controlled by switches S1~S n Opening the circuit disconnects the corresponding output branches 2111~211n, or via control switches S1~S n The closure of the circuit enables the corresponding output branches 2111~211n to conduct.

[0037] It should be noted that after the n output branches 2111~211n are sequentially conducted once, the corresponding output voltage signals Vo1~Vo can be generated for each branch. n Energy transfer. Due to the energy storage function of the output capacitor, the unconducted output branch will still stably output the corresponding output voltage signal, and obtain energy from the inductive energy storage element when it is turned on again.

[0038] like Figure 2 As shown, the power controller 201 operates as follows: the first input terminal FW is coupled to the secondary winding 222 of the transformer TX, and the second input terminal CS is coupled to the current sampling resistor Rs of the primary current of the transformer TX. The drive signal DR is coupled to the control terminal of the power switch M1 connected to the primary winding 221. The output voltage signals Vo1~Vo n Coupled to n output loads R respectively L1 ~R Ln The modulation control unit 320 controls the n-channel feedback signals V FB1 ~V FBn At least one internal reference voltage signal Vref and current sampling voltage signal V are included. CSThe signal is processed to form a modulation control signal. Under the control of the modulation control signal, the drive unit 330 outputs a drive signal DR to control the on and off of the power switch M1. During the on-time of the power switch M1, the input voltage signal Vin is applied to the primary winding 221 of the transformer TX, causing the transformer TX to generate primary winding excitation. Simultaneously, the primary winding current forms a primary current sampling signal, i.e., the current sampling voltage signal V, across the current sampling resistor Rs. CS The signal is coupled to the CS port of the modulation control unit 320 and compared with the threshold voltage Vth inside the modulation control unit 320. When the sampling voltage Vth of the primary current is... CS >Vth, the modulation control signal (PWM pulse) is turned off, which in turn turns off the power switch M1. After the power switch M1 is turned off, the energy of the primary winding 221 is transferred to the secondary winding 222, and the secondary winding 222 begins to demagnetize. During the demagnetization of the secondary winding 222, the switches S1~S2111~211n connecting each output branch are demagnetized. n Under the control of the equalization control unit 340, the switches are turned on sequentially in a time-division manner, that is, the next switch turns on the instant the previous switch turns off. Here, "before and after" refers to the sequence of the switches, not their position. In this way, at any given moment during the entire demagnetization period, there is always one output branch that is turned on, and there is no situation where multiple output branches are turned on simultaneously, so that the energy of the secondary winding 222 of the transformer TX is transferred to the turned-on output branch.

[0039] The power controller 201 of this application can implement two loops in the switching power supply system 200, namely a first loop and a second loop. The power controller 201 includes a first control circuit and a second control circuit. The first control circuit includes a modulation control unit 320, a drive unit 330, and a feedback unit 310. The first control circuit forms a first loop with the inductive energy storage element TX and the power switch M1. The second control circuit includes n output branches 2111~211n, the feedback unit 310, and an equalization control unit 340. The second control circuit forms a second loop with the inductive energy storage element TX. The first loop and the second loop are decoupled from each other. In this embodiment, the first control circuit and the second control circuit share the feedback unit 310, which saves circuit area. In other embodiments, the power controller 201 may include two independent feedback units, one of which provides a feedback signal to the modulation control unit 320; the other feedback unit provides a feedback signal to the equalization control unit 340.

[0040] According to the power controller 201 described above, the control variable generated by the first loop is the modulation control signal (PWM signal) of the power switch M1 on the primary side of the transformer TX, and the control variable generated by the second loop is the control signal Ts1~Ts coupled to the secondary side (i.e., the secondary side) of the transformer TX, used to control whether each output branch 2111~211n is turned on or off. n Although in some embodiments the first and second control circuits share the feedback unit 310, the first and second loops are decoupled from each other, and there is no cross-control between them. This can greatly improve the cross-regulation of the switching power supply system 200, meaning that when the load of one output branch changes abruptly, the voltage of other branches is less affected. Furthermore, since there is no cross-control, the second loop can operate in the background. Due to the decoupling, both the first and second loops can be designed as fast loops. Using a wider bandwidth allows both loops to respond quickly to sudden load changes. Because of the decoupling, the two loops can use similar bandwidths, avoiding instability caused by the poles of two coupled loops being too close. Furthermore, according to the power controller 201 of this application, there is no need to introduce components such as LDOs into the switching power supply system 200, simplifying the design of the control and compensation circuits and reducing costs.

[0041] In some embodiments, the feedback signal V FB1 ~V FBn It is composed of the corresponding output voltage signals Vo1~Vo n The voltage is obtained through voltage division, where the output voltage signals Vo1~Vo n With feedback signal V FB1 ~V FBn The ratio is equal to the ratio of the preset voltage value to the reference voltage Vref. The preset voltage value is the preset output voltage value for each output branch 2111~211n, for example, 15V, 12V, and 5V. The first loop is further configured to cause the n output voltage signals to converge to fixed preset voltage values, and the second loop is further configured to ensure that when convergence reaches a steady state, the ratio between each output voltage signal and its corresponding preset voltage value is the same.

[0042] Figure 3 This is a schematic diagram of the first loop formed when a switching power supply controller according to an embodiment of this application is used in a switching power supply system. (Reference) Figure 3As shown, the first loop includes a modulation control unit 320, a drive unit 330, a feedback unit 310, an inductive energy storage element (transformer TX), and a load. In this embodiment, the modulation control unit 320 is a PWM control unit, and the modulation control signal is a PWM signal. The PWM control unit includes an energy adjustment unit 321, a trigger 322, and a comparator 323. The energy adjustment unit 321 is used to generate a threshold voltage signal Vth, and to adjust the load according to at least one feedback signal V. FB1 ~V FBn A set signal S is generated by combining the reference voltage signal Vref. The threshold voltage signal Vth is then compared with the current sampling voltage signal V. CS A reset signal R is generated by comparator 323. The set signal S and the reset signal R are respectively used as inputs to flip-flop 322 to cause it to generate a PWM signal. Specifically, the set signal S is used to determine the frequency of the PWM signal, and the threshold voltage signal Vth is used to compare with the current sampling voltage signal V. CS Together, they determine the pulse width of the PWM signal.

[0043] In some embodiments, trigger 322 is an RS trigger.

[0044] In some embodiments, the threshold voltage signal Vth is used in conjunction with the current sampling voltage signal V CS The comparison result determines the pulse width of the PWM signal. The threshold voltage signal Vth can be a constant or a variable. If the threshold voltage signal Vth is constant, the pulse width of the PWM signal is fixed, which is equivalent to a fixed conduction time. In this embodiment, the threshold voltage signal Vth and the current sampling voltage signal V... CS The inputs are respectively fed to the positive input and negative output of comparator 323. When Vcs > Vth, the PWM pulse is turned off (goes low), which in turn causes M1 to turn off.

[0045] according to Figure 3 In the first loop shown, the PWM signal is amplified by the drive unit 330 to output a drive signal DR. This drive signal DR can control the power switch M1 to turn on and off, thereby controlling the primary-side power supply to the output load R. L1 ~R Ln The total energy is used to bring the load voltage to a fixed preset voltage value, and to balance the total energy consumed when each output branch reaches the preset output voltage during steady-state convergence.

[0046] Figure 4 This is a schematic diagram of the second loop formed by a switching power supply controller according to an embodiment of this application when used in a switching power supply system. (Reference) Figure 4As shown, the second loop includes n output branches 2111~211n, a feedback unit 310, a balance control unit 340, an inductive energy storage element (transformer TX), and a load. Specifically, the secondary current Isec of the transformer TX is coupled to the n output branches 2111~211n through the first input terminal FW.

[0047] according to Figure 4 In the second loop shown, the secondary current Isec of transformer TX flows into n output loads R through n output branches 2111~211n in a time-sharing manner. L1 ~R Ln n output loads R L1 ~R Ln The output voltage is normalized and divided by the feedback unit 310 (based on the proportional relationship of the output voltage setpoint) to generate n feedback signals V. FB1 ~V FBn n-way feedback signal V FB1 ~V FBn The signals are input to the equalization control unit 340, which generates control signals Ts1~Ts for n branch control switches. n This signal controls branch switches S1~S n The conduction time is determined, thereby controlling the output load R flowing into n branches. L1 ~R Ln The current. In other words, the control signals Ts1~Ts n The conduction time of each output branch 2111~211n on the secondary side is controlled within one power switching cycle, so that the total energy transferred to the secondary side is distributed to each output branch 2111~211n according to the load conditions (load size and normalization coefficient of each branch voltage) of each output branch 2111~211n on the secondary side.

[0048] It can be seen that the control variables Ts1~Ts in the second loop n Since the control variable PWM of the first loop is independent, the second loop is decoupled from the first loop. When the second loop converges to steady state, V FB1 =V FB2 =…=V FBn Since the ratio of the output voltage signal to the feedback signal is equal to the ratio of the preset voltage value to the reference voltage signal Vref, this means that the ratio between the output voltage of each branch and the preset voltage value is the same, but they may not necessarily converge to the preset voltage value. The convergence goal of the first loop is to make the output voltage of each output branch converge to a fixed preset voltage value. The convergence goals of the first loop and the second loop are different, thus achieving decoupling.

[0049] The following describes the specific implementation of the equalization control unit 340.

[0050] Figure 5 This is a circuit diagram of the equalization control unit in a power controller according to an embodiment of this application. Figure 6 yes Figure 5 The waveform diagram corresponding to the equalization control unit is shown below. Figure 5 As shown, the equalization control unit 340 includes n-1 cascaded loop gain units 341, wherein the j-th loop gain unit 341 is used to adjust the j-th feedback signal V. FBj and the (j+1)th feedback signal V FBj+1 Generate the j-th control signal T sj At the same time, it forces V FBj =V FBj+1 Where j is a positive integer from 1 to n-1. In some embodiments, the loop gain unit is a proportional-integral unit, i.e. Figure 5 The PI unit shown is composed of an integral module and a proportional module, providing loop gain and loop compensation. This specification uses loop gain unit 341 as an example of a PI unit. In other embodiments, loop gain unit 341 can also be implemented in other ways. For example, loop gain unit 341 is a Type II compensation network, which includes a transconductance error amplifier and a network of resistors and capacitors connected to the output of the transconductance error amplifier. As another example, loop gain unit 341 is a Type III compensation network, which includes an operational amplifier and multiple resistors and capacitors arranged around the operational amplifier to provide three poles and two zeros in the frequency domain. As yet another example, loop gain unit 341 can be implemented by a digital compensator in a digital signal processor (DSP), which is configured to execute a proportional-integral (PI) or proportional-integral-derivative (PID) control algorithm.

[0051] In some embodiments, the PI unit can be either continuous analog control or discrete control.

[0052] Figure 7 This is a functional block diagram of a loop gain unit implemented using analog integral-proportional control. For example... Figure 7 As shown, V FBj+1 and V FBj Error E j Integral gain Gi j The integration module generates the error integration term Eint. j Meanwhile, E j After being amplified by the proportional amplifier module Gp j Forming a proportionally magnified term Ep j Error integral term Eint j And the scaling term Ep j The summation forms the control signal Vctl. j The signal is converted from voltage to pulse module A. jOutput the branch switch control signal Ts for the j-th branch. j Where j is a positive integer from 1 to n-1. Since Figure 7 The PI unit shown contributes a sufficiently high loop gain, so in the closed-loop steady state, it will cause V FBj =V FBj+1 Since the entire equalization control unit 340 is composed of these cascaded PI units, the steady-state convergence result is expressed by formula (1): (1) Formula (2) is Figure 7 The transfer function of the j-th PI unit: (2) One of the integration modules contributes to the pole at the origin, and another proportional amplifier module contributes to the zero in the left half-plane. This zero improves the phase margin and enhances the loop stability.

[0053] Figure 8 This is a functional block diagram of a discrete-control PI unit. For example... Figure 8 As shown, V FBj+1 and V FBj Error E j The sampling module samples periodically to form a discrete error sampling signal Es. j The signal is subjected to discrete integral Gi. j and scale up Gp j This forms the integral signal Eint. j and proportionally amplified signal Ep j Integral signal Eint j and proportionally amplified signal Ep j The summation forms the control signal Vctl. j And through voltage pulse conversion module A j The control signal Ts is converted into the switch of the j-th branch. j Similar to the above-mentioned analog PI unit, the following formula (3) is the recursive expression of the discrete integral, formula (4) is the recursive control equation of the discrete PI unit, and formula (5) is the Z-transform expression of the discrete equation.

[0054] (3) (4) (5) In the above formulas (3) to (5), the subscript j represents the j-th output branch, k represents the cycle number of power switch M1, and Gi j Gp represents the integral coefficient of the j-th output branch. jA is the proportional coefficient of the j-th output branch. j is the gain coefficient of the voltage-to-pulse module of the j-th output branch. k is a positive integer greater than or equal to 1.

[0055] like Figure 5 As shown, in some embodiments, n-1 PI units are used to generate n-1 control signals Ts1~Ts in a one-to-one correspondence. n-1 The nth control signal Ts n It is generated by logic unit 342. In this embodiment, the equalization control unit 340 further includes logic unit 342, which is used to generate control signals Ts1~Ts from the first to the (n-1)th channels. n-1 and control pulse T ET Perform logical operations to obtain the nth control signal Ts n Among them, the control pulse T ET One switching cycle of power switch M1 encompasses the entire demagnetization phase of the inductive energy storage element in the switching power supply system. Combined with... Figure 6 As shown, control pulse T ET The rising edge of Ts1 is aligned with the rising edge of Ts1, controlling the pulse T. ET The falling edge and Ts n The falling edge is aligned, meaning all control signals are located at T. ET During the opening phase.

[0056] In some embodiments, the first to nth control signals Ts1~Ts n In a given pair of adjacent control signals, when the preceding control signal switches from an on level to an off level, the following control signal switches from an off level to an on level. The nth control signal Ts... n Switch to the off level after the demagnetization phase ends.

[0057] Figure 9 This is a waveform diagram of the second loop formed by the power controller according to an embodiment of this application. From top to bottom, the waveforms are: the modulation control signal PWM, the primary current signal Iprm of the transformer TX, the secondary current signal Isec of the transformer TX, and the switching control signals Ts1~Ts of the n output branches. n Ts1 turns on at a certain point in time after the PWM pulse is turned on, while Ts n Turn off after the secondary winding has been demagnetized. Ts1~Ts n They will be opened sequentially, but without overlap. Figure 6 In the waveform diagram shown, the turn-on time of Ts1 is... Figure 9The turn-on times of Ts1 shown are different, but they all turn on at a certain point after the PWM pulse is activated. In this embodiment, the conduction level is high. That is, a high level triggers turn-on, and a low level triggers turn-off. In other embodiments, the opposite can be true.

[0058] according to Figure 9 As shown, the demagnetization phase of the secondary winding corresponds to the period from the rising edge 911 of one cycle (Isec) to the rising edge 912 of the next cycle. The excitation phase of the primary winding corresponds to the rising segment of Iprm, starting from the starting point 921 and ending at the falling edge 922. All switching control signals Ts1~Ts n During the demagnetization phase, the circuit is sequentially switched on, and the last control signal Ts is activated. n Turn off before the start of the next excitation phase at 921.

[0059] Figure 10 This is a dynamic adjustment waveform diagram of the second loop formed by the power controller according to an embodiment of this application. Four cycles are shown for illustrative purposes. During cycle T0, the j-th output and the (j+1)-th output are in a steady state, i.e., the sampling signal error E1 = 0, and the second loop converges. During cycle T1, the load on the j-th output suddenly becomes light, causing the j-th output voltage to increase. Therefore, at time t20, the feedback signal V of the j-th output... FBj The feedback signal V, which is greater than the output of channel j+1, FBj+1 According to the recursive control equation of the aforementioned formula (4), in period T2, Ts j The pulse width will decrease, thereby reducing the energy supply to the j-branch; while Ts j+1 The pulse width increases, which in turn increases the energy supply of the j+1 branch. Therefore, at the beginning time t30 of the third switching cycle T3, the error E3 of the sampling signal decreases. Similarly, at the beginning time t40 of the fifth cycle, the error E4 of the sampling signal decreases to 0, and the second loop converges again.

[0060] As described above, the first and second loops of this application are decoupled, allowing the second loop's equalization algorithm to run entirely in the background. Therefore, if the first loop employs a fast-response control method, such as ripple control, the dynamic response and cross-regulation of the entire switching power supply system can be significantly improved.

[0061] In some embodiments, the equalization control unit 340 does not include a logic unit 342, but instead includes a switching element. The switching element is used to switch the nth output branch from the off state to the on state when the (n-1)th control signal switches from an on level to an off level, and to switch back to the off state after the demagnetization phase of the inductive energy storage element in the switching power supply system ends. Figure 11As shown, in this embodiment, the switching element is diode D2. Figure 11 The diagram shows a circuit diagram of a switching power supply system with three outputs. This includes a power controller 1101 according to another embodiment of this application. The power controller 1101 includes a first input terminal FW, three output branches 1111~1113, a feedback unit 1110, a modulation control unit 1120, a second input terminal CS, a drive unit 1130, and an equalization control unit 1140. In this embodiment, switches S1 and S2 are respectively installed on output branches 1111 and 1112, while a diode D2 is installed on output branch 1113. D2 conducts when the conduction voltage is reached, and does not conduct otherwise, thus also realizing the switching function. According to this embodiment, the equalization control unit 1140 only needs to output two control signals Ts1 and Ts2, simplifying the circuit, omitting logic components, and further simplifying the structure.

[0062] In this embodiment, the modulation control unit 1120 is a PWM control unit, and the modulation control signal is a PWM signal.

[0063] exist Figure 11 In the illustrated embodiment, the switching power supply system 1100 and Figure 2 The switching power supply system 200 shown is similar, also a flyback switching power supply system. The transformer TX is also a flyback transformer. Unlike switching power supply system 200, switching power supply system 1100 has an AC input, not an AC input. Figure 2 The switching power supply system 1100 includes an input bridge rectifier 1150, an input capacitor Cin, and a secondary rectifier diode D1 at the input terminals. The operating principle of the switching power supply system 1100 is as follows: the first input terminal FW is coupled to the secondary rectifier diode D1, and the second input terminal CS is coupled to the current sampling resistor Rs of the primary current of the transformer TX. The drive signal DR is coupled to the control terminal of the power switch M1 connected to the primary winding 1161. The output voltage signals Vo1~Vo3 are coupled to the three output loads R1 and R2 respectively. L1 ~R L3 The output voltage signals Vo1~Vo3 are input to the feedback unit 1110 and normalized into three feedback signals V. FB1 ~V FB3 Three-way feedback signal V FB1 ~V FB3 The signals are input to the modulation control unit 1120 and the equalization control unit 1140, respectively. The output signal PWM of the modulation control unit 1120 is coupled to the input of the drive unit 1130. Under the control of the PWM signal, the drive unit 1130 outputs a drive signal DR to control the on and off of the power switch M1. This is achieved by adjusting Vref and V... FB1 ~VFB3 At least one feedback signal is processed, and the modulation control unit 1120 triggers the PWM pulse to turn on, thereby turning on M1, energizing the transformer TX, and simultaneously increasing the primary current linearly. The sampling signal V of the primary current formed across the current sampling resistor Rs is then processed. cs Coupled to the CS port of the modulation control unit 1120 and compared with the threshold voltage Vth inside the modulation control unit 1120, when the sampling voltage V of the primary current... cs >V th The PWM pulse is terminated, which in turn causes M1 to turn off. The equalization control unit 1140 receives three feedback signals V from the feedback unit 1110. FB1 ~V FB3 And generate two control signals T S1 T S2 The branch switches S1 and S2 of output branches 1111 and 1112 are controlled to open and close respectively. The third output branch 1113 is controlled to open and close via diode D2.

[0064] The following combination Figure 12 and Figure 13 illustrate Figure 11 The equalization control unit 1140 in the power controller 1101.

[0065] Figure 12 yes Figure 11 The functional block diagram of the equalization control unit 1140 of the three-output power controller 1101 shown is given in the form of a discrete PI unit. For example... Figure 12 As shown, the equalization control unit 1140 is composed of two cascaded PI units 1210 and 1220. The input of the first PI unit 1210 is the feedback signal V from the first output branch 1111. FB1 and the feedback signal V of the second output branch 1112 FB2 The output is the control signal Ts1 of the switch in the first output branch 1111. The input of the second PI unit 1220 is the feedback signal V of the second output branch 1112. FB2 and the feedback signal V of the third output branch 1113 FB3The output is the control signal Ts2 for the switch of the second output branch 1112. In the first PI unit 1210, the error signal E1 is sampled by the sampling module to form a discrete error sampling signal Es1. This signal is then subjected to discrete integration and proportional amplification to form an integral signal Eint1 and a proportional amplification signal Ep1. The two are added together to form the control signal Vctl1. The control signal Vctl1 is converted into the switch control signal Ts1 for the first branch by the voltage-to-pulse conversion module (V / P). In the second PI unit 1220, the error signal E2 is processed in the same way to generate the control signal Ts2 for the switch of the second output branch 1112.

[0066] The following formulas (6) and (7) represent the recursive expressions for the discrete integrals in the first and second PI units 1210 and 1220, respectively: (6) (7) Formulas (8) and (9) are used to represent the recursive control equations for the first and second PI units 1210 and 1220, respectively: (8) (9) Formulas (10) and (11) are used to represent the Z-transform expressions of the recursive control equations of the first and second PI units 1210 and 1220, respectively.

[0067] (10) (11) The Z-transform expression shows that the control equation has one pole and one zero. The other pole in the second loop is contributed by the output load, and the zero cancels out the phase shift of one of the poles. Therefore, the entire second loop is stable and convergent. Since the PI control unit contributes a sufficiently high loop gain, and the entire equalization control unit 1140 is composed of these cascaded PI modules, the final steady-state convergence result is: (12) Figure 13 Is with Figure 12 The circuit diagram corresponding to the functional block diagram. For example... Figure 13As shown, each PI unit consists of an integrator module and a proportional amplifier module. Taking the first PI unit 1210 as an example, the integrator module includes a transconductance amplifier gm, a current switch S1, and an integrating capacitor Ci1. The proportional amplifier module includes an amplifier A, a pulse sampling switch S2, and a sampling capacitor Cp1. The control signals of these switches S1 and S2 are synchronized with the PWM signal, meaning they switch once within one PWM cycle. The transconductance amplifier gm in the integrator module converts the error value between the feedback voltage signals of two adjacent output branches into an error current signal I. E12 The error current passes through switch S1 to form a pulsed integrating current, which in turn forms an error integrating voltage signal on integrating capacitor Ci1. Amplifier A of the proportional amplifier module amplifies the error value of the feedback voltage signals of the two adjacent branches, and then the error is sampled by switch S2 onto sampling capacitor Cp1 to form a proportionally amplified signal. The error integrating voltage signal and the proportionally amplified signal are added together and then converted by the voltage-pulse module V / P into control signals Ts1 and Ts2 for the branch switches.

[0068] The following description, in conjunction with the accompanying drawings, illustrates the modulation and control unit 1120 in the power controller; this section also serves as an explanation. Figure 2 The modulation control unit 320 in the illustrated embodiment.

[0069] Figure 14 This is a circuit diagram of the modulation control unit in a power controller according to an embodiment of this application. Figure 14 As shown, the modulation control unit 1120 includes an energy adjustment unit 1410, a trigger 1420, and a comparator 1430. The energy adjustment unit 1410 includes n comparators 1411 and OR gates 1412, and n feedback signals V. FB1 ~V FBn n comparators 1411 are input respectively. Each comparator 1411 compares its corresponding feedback signal and reference voltage signal Vref and generates a comparison result. The n comparison results are input to an OR gate 1412 to obtain a set signal S. Comparator 1430 is used to compare the threshold voltage signal Vth with the current sampling voltage signal V. CS A reset signal R is generated. In this embodiment, n=3. This embodiment sets OR gate 1412 so that when n feedback signals V... FB1 ~V FBn When any one of the inputs drops to the reference voltage signal Vref, a high level is output to the set input of flip-flop 1420. In other embodiments, OR gate 1412 can be implemented by other circuits with similar functionality.

[0070] Figure 14The diagram, also known as multi-source ripple control, utilizes the coordinated control of the switching ripples of the three output branches to generate a PWM signal. It is a PWM control unit based on multi-source ripple control. The power switch M1 periodically turns on and off. In each switching cycle, the load capacitance C of each output branch... L1 ~C Ln Both the capacitor and the power switch M1 receive charge injected from the secondary winding and simultaneously draw charge through the load current, thus generating ripple on the capacitor. This ripple has the same switching frequency as the power switch M1, and is therefore also called switching ripple.

[0071] Figure 15 yes Figure 14 The dynamic waveform diagram of the modulation control unit in the illustrated embodiment. Figure 15 As shown, the switching ripple manifests as periodic fluctuations in each feedback signal. When any feedback signal first drops to the reference voltage Vref, the PWM signal is triggered to turn on, thereby triggering the power switch M1 to turn on. Figure 15 As shown, at time t1 of the first cycle, VFB1 crosses Vref first, thus triggering the PWM to turn on; at time t2 of the second cycle, VFB2 crosses Vref first, thus triggering the PWM to turn on; at time t3 of the third cycle, VFB3 crosses Vref first, thus triggering the PWM to turn on. That is, within these three switching cycles, a feedback signal triggers the PWM to turn on, thereby causing the power switch M1 to conduct.

[0072] Figure 16 This is a circuit diagram of a modulation control unit in a power controller according to another embodiment of this application. The modulation control unit 1600 includes an energy adjustment unit 1610, a trigger 1620, and a comparator 1630. The energy adjustment unit 1610 includes a weighted comparator 1611 and n weighted current generating modules 1612, wherein the j-th weighted current generating module 1612 is used to generate the j-th control signal Ts. j Under the control of , a weighted current Iwj positively correlated with the load size corresponding to the j-th output branch is generated, where the load is the load Rj connected to the second terminal of the j-th output branch in the switching power supply system; the weighted comparator 1611 includes n differential pairs and a current mirror, the inputs of the j-th differential pair are the reference voltage signals of the j-th feedback signal, and the output terminals of the n differential pairs are connected to the input terminal of the current mirror so that the output currents of each differential pair are superimposed at the input terminal of the current mirror to form a weighted error signal, which is used as a set signal S, where j = 1 to n-1 positive integers.

[0073] exist Figure 16 In the example shown, n=3. Figure 16A weighted current generating module 1612 is outlined with a dashed line. The three weighted current generating modules are relatively independent. Taking weighted current generating module 1612 as an example: weighted current generating module 1612 corresponds to... Figure 11 The first output branch and its load R L1 Here, Ib1 is the bias current, which is connected to the positive input of an OTA (operational transconductance amplifier) ​​via switch Sc1. The positive input of this OTA is also connected to a capacitor C1 and another grounded switch Sw1. The control signal Ts1 for switch Sc1 is the control signal for the first output branch mentioned above. During the conduction of switch Sc1, the current Ib1 integrates across capacitor C1, forming an integrated voltage. This integrated voltage is further processed by a V2I (voltage-controlled current source) circuit (e.g., ...). Figure 16 M in 16-1 M 16-2 and M 16-3 This is converted into a weighted current Iw1. Since the integrated voltage is proportional to the pulse width of Ts1, and the weighted current Iw1 is proportional to the integrated voltage, and since the pulse width of Ts1 is positively correlated with the load size, the weighted current is proportional to the load R of the first output branch. L1 Positive correlation. Similarly, in the other two weighted current generation modules, Iw2 and Iw3 are respectively positively correlated with... Figure 11 The load R of the second and third output branches L2 R L3 Positive correlation. Since the three output branches are turned on at different stages of the demagnetization process, the secondary inductor current corresponding to the output branch turned on later is smaller. This can be mitigated by adjusting R1, R2, R3, or I... b1 I b2 I b3 To balance the changes in inductor current.

[0074] refer to Figure 16 As shown, the control signal Ts3 of the switch Sc3 of the third weighted current generation module on the far right is expressed by formula (13): (13) Among them, Tdem k This represents the demagnetization time in the k-th switching cycle, where k represents the number of switching cycles.

[0075] like Figure 16 As shown, in this embodiment, the weighted comparator 1611 is an n-differential input comparator, where n=3. Each differential pair consists of two MOS transistors. For example, the first differential pair connected to Iw1 includes M... 10 and M 11 The second difference pair connected to Iw2 includes M. 12 and M13 The third difference pair connected to Iw3 includes M. 14 and M 15 The negative input of each difference pair is connected to Vref, and the positive inputs are connected to Vref respectively. FB1 V FB2 V FB3 The outputs of the differential pair are then connected to M respectively. 16 M 17 The input terminals of the current mirror are the two drains. The output currents of each differential pair are superimposed at the input terminals of the current mirror to form a weighted error signal, which is then transmitted from M. 17 The drain output. In some embodiments, the weighted error signal can be directly connected to the S terminal of the flip-flop 1620 as a set signal.

[0076] In some embodiments, the weighted comparator 1611 further includes a weighted amplifier, which amplifies the weighted error signal, and the amplified weighted error signal serves as a set signal. Figure 16 In the embodiment shown, M 17 The drain outputs the first-stage amplified signal of the weighted error signal, which is input to M. 18 The gate, after passing through M 18 and I b4 The common-source amplifier, consisting of two stages of amplification, outputs a comparison result via an inverter 1640. This comparison result is input to the S-terminal of a flip-flop 1620 as a set signal, activating the PWM pulse. cs Vth and Vth are respectively connected to the two differential terminals of a comparator. The comparison result is coupled to the reset terminal R of the flip-flop to turn off the PWM pulse.

[0077] Figure 16 The modulation control unit 1600 shown employs a weighted ripple control comparator for ripple control, and is a PWM control unit based on weighted ripple control. In application... Figure 14 In the multi-element ripple control corresponding to the embodiment shown, if the load of a certain output branch is very light, the ripple is very small and easily interfered with. Figure 16 The weighted ripple control shown can amplify the ripple through weighting, thereby avoiding these problems.

[0078] Figure 17 This is a block diagram of a modulation control unit in a power controller according to another embodiment of this application. (See reference) Figure 17 In this embodiment, the modulation control unit 1700 includes an energy adjustment unit 1710, a trigger 1720, and a comparator 1730. The energy adjustment unit 1710 includes a weighted summation unit 1711, used to adjust at least one feedback signal VFB1~VFB. nA weighted summation is performed and a weighted summation signal VFB is output. In this embodiment, n=3. Operational amplifier 1712 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal receives the weighted summation signal VFB, and the second input terminal receives a reference voltage signal Vref. Operational amplifier 1712 amplifies the difference between the weighted summation signal VFB and the reference voltage signal Vref, and outputs an error amplification signal at the output terminal. Compensation network 1713, coupled to the output terminal of operational amplifier 1712, is used to perform frequency compensation on the error amplification signal to stabilize the loop. Frequency generation unit 1714, coupled to the output terminal of operational amplifier 1712, is used to generate a set signal S with a first frequency based on the error amplification signal. Threshold generation unit 1715, coupled to the output terminal of operational amplifier 1712, is used to generate a threshold voltage signal Vth based on the error amplification signal. Comparator 1730 includes a first comparator input terminal, a second comparator input terminal, and a comparator output terminal. The first comparator input terminal receives the current sampling voltage signal V from the input signal of the switching power supply system. cs The input of the second comparator is coupled to the output of the threshold generation unit 1715 to receive the threshold voltage signal Vth. Comparator 1730 is used to sample the current voltage signal Vth. cs When the voltage signal Vth exceeds the threshold voltage, a reset signal R is output through the output terminal. The reset signal R is used as input to the flip-flop 1720.

[0079] Figure 17 The diagram shows a PWM control unit that generates PWM signals based on operational amplifiers and peak comparators. Figure 15 and Figure 16 Compared to the PWM control unit shown, Figure 17 The PWM control unit has better anti-interference capability and load regulation, but the dynamic response may be slightly slower.

[0080] This application is based on Figure 11 The three-output switching power supply system shown was simulated to verify its dynamic and cross-regulation performance. Figure 18 Simulation results are shown, where the preset output voltages of the three outputs Vo1, Vo2, and Vo3 are 5V, 12V, and 15V, respectively; and the initial load currents of the three branches are 200mA, 100mA, and 100mA, respectively. The waveforms in the figure show that the three branches synchronously reach the preset output voltages. The horizontal axis represents the number of switching cycles. In the 1000th switching cycle, the load current of the second branch is instantaneously switched from 100mA to 1A, while the output voltages of all branches remain almost completely unchanged. This demonstrates that the power controller proposed in this invention achieves excellent load regulation, dynamic response, and cross-regulation performance.

[0081] In some embodiments, the modulation control unit in the power controller may not be a PWM control unit. Figure 19 A three-output isolated flyback switching power supply system is shown. (Reference) Figure 19 As shown, the switching power supply system 1900 includes a power controller 1901 according to another embodiment of this application. The power controller 1901 includes a first input terminal FW, three output branches 1911-1913, a feedback unit 1910, a modulation control unit 1920, a second input terminal CS, a drive unit 1930, and an equalization control unit 1940. The modulation control unit is a PFM (Pulse Frequency Modulation) control unit, and the modulation control signal is a PFM signal. The drive unit 1930 is an isolated drive unit. The switching power supply system 1900 includes a transformer TX. The primary winding 1961 (primary side) and the secondary winding 1962 (secondary side) of the transformer TX are not grounded. The primary winding 1961 corresponds to the primary ground 1971, and the secondary winding 1962 corresponds to the secondary ground 1972. The reference ground of the PFM signal is the secondary ground 1972 (or secondary ground). The PFM signal is coupled to the primary winding through the isolation drive unit and generates a drive signal DR. The reference ground of the drive signal DR is the primary ground 1971.

[0082] In this switching power supply system 1900, the AC input is rectified by the bridge rectifier 1950 and coupled to the first terminal 19611 of the primary winding 1961 of the transformer TX. The second terminal 19612 of the primary winding 1961 is connected to the drain of the power switch M1. The source of the power switch M1 is connected to the primary ground 1971 through a current sampling resistor Rs. The gate of the power switch M1 is coupled to the drive signal DR output by the power controller 1901. The secondary winding 1961 is coupled to the first input terminal FW of the power controller 1901 through a secondary rectifier diode D1. The output terminals Vo1~Vo3 of the power controller 1901 are respectively connected to three output capacitors C. L1 ~C L3 and 3 output loads R L1 ~R L3 Three output capacitors C L1 ~C L3 and output load R L1 ~R L3 All secondary land 1973. Secondary land 1973 and the original border land 1972 share land.

[0083] Power controller 1901 and Figure 11The power controller 1101 shown is basically the same, except that the power controller 1901 is an isolated flyback type, and the primary and secondary sides of the transformer TX are electrically isolated, i.e., they do not share a common ground. The power switch M1, which controls the on and off of the primary winding 1961 of the transformer TX, is connected to the primary ground 1971 through the current sampling resistor Rs. Therefore, the reference ground of the drive signal DR of the power switch M1 should be the primary ground 1971, and it needs to be electrically isolated from the secondary side. The PFM control unit outputs a PFM signal with the secondary ground as the reference ground. This PFM signal is synchronously coupled to the primary side through the isolation device (which can be an optocoupler, magnetic coupler, or capacitive coupling) in the isolation drive unit, and converted into a PFM synchronization signal with the primary ground 1971 as the reference ground. The synchronization signal can be used as a set signal S to trigger the pulse of the primary-side drive signal DR to turn on and conduct the power switch M1; the primary-side current sampling signal Vcs is coupled to the CS port of the primary side of the isolation drive unit and input to its internal peak current comparator, and compared with another input signal of the comparator, namely the peak current threshold Vth. When Vcs>Vth, a turn-off signal is generated to turn off the pulse of the DR signal, thereby turning off the power transistor M1.

[0084] The 1901 power controller is suitable for applications requiring electrical isolation, such as switching power supply systems for mobile phone chargers.

[0085] This application also proposes a switching power supply system, including any of the power controllers described above. For example... Figure 2 The switching power supply system 200 shown is... Figure 11 The switching power supply system 1100 shown is... Figure 19 The switching power supply system 1900 is shown. Due to the inclusion of the power controller of this application, the first and second loops of the switching power supply system are decoupled, resulting in better dynamic response and cross-regulation performance.

[0086] Figure 20 This is a block diagram of a switching power supply system according to another embodiment of this application. Figure 20 As shown, the switching power supply system 2000 of this embodiment includes a power controller 2001; an inductive energy storage element including a power inductor L1, the first terminal 2011 of which is connected to the second input terminal CS of the power controller 2001, and the first terminal 2011 of which is also connected to the first input terminal FW of the power controller 2001 through a current sampling resistor Rs; the second terminal 2012 of which is connected to the negative terminal of a freewheeling diode D1, and the positive terminal of the freewheeling diode D1 is grounded; the second terminal 2022 of a power switch M1 is connected to the second terminal 2012 of the power inductor L1; the first terminal 2021 of the power switch M1 is used to receive the input voltage signal Vin, and the control terminal 2023 is used to receive the drive signal DR; n output loads R L1 ~R LnEach of the n output branches is connected to the second terminal of the n output branches in a one-to-one correspondence; n output capacitors C L1 ~C Ln One-to-one correspondence with n output loads R L1 ~R Ln in parallel.

[0087] In some embodiments, the power switch M1 is a MOSFET. The first terminal 2021 of the power switch M1 is the drain, and the second terminal 2022 is the source.

[0088] The Switching Power Supply System 2000 is a non-synchronous buck switching power supply system suitable for AC-DC conversion scenarios, especially for small to medium power non-isolated power supply scenarios. It is also suitable for buck applications with high-voltage DC inputs above 100V, such as industrial 48V / 240V bus power supply, high-voltage auxiliary power supply for new energy vehicles, and photovoltaic high-voltage input buck applications. Compared to synchronous buck systems, its freewheeling uses a high-voltage fast recovery diode, eliminating the need for an additional high-voltage synchronous rectifier drive circuit, resulting in higher reliability and lower cost.

[0089] Figure 21 This is a block diagram of a switching power supply system according to another embodiment of this application. Figure 21 As shown, the switching power supply system 2100 of this embodiment includes a power controller 2101; an inductive energy storage element, including a power inductor L1, wherein the first end 2111 of the power inductor L1 is connected to the first input terminal FW of the power controller 2101, and the second end 2112 of the power inductor L1 is connected to the second input terminal CS of the power controller 2101; and a first power switch M. 211 The second terminal 2122 is connected to the second terminal 2112 of the power inductor L1, and is also connected to the second input terminal CS of the power controller 2101. The first power switch M 211 The first terminal 2121 is used to receive the input voltage signal Vin, and the first power switch M 211 The control terminal 2123 is used to receive the drive signal DR; the second power switch M 212 The first terminal 2131 is connected to the second terminal 2112 of the power inductor L1, and the second power switch M 212 The second terminal 2132 is grounded, and the second power switch M 212 The control terminal 2133 is connected to the synchronous output terminal SYNC of the power controller 2101. The synchronous output terminal SYNC is used to output a synchronous control signal to enable the second power switch M 212 The power inductor L1 is turned on during the freewheeling phase; n output loads R L1 ~R Ln Each of the n output branches is connected to the second terminal of the n output branches in a one-to-one correspondence; n output capacitors C L1 ~C LnOne-to-one correspondence with n output loads R L1 ~R Ln in parallel.

[0090] In some embodiments, power switch M 211 It's a MOSFET. Power switch M 211 The first terminal 2121 is the drain, and the second terminal 2122 is the source.

[0091] The switching power supply system 2100 is a synchronous buck switching power supply system. Compared to the asynchronous switching power supply system 2000, the power controller 2101 outputs a synchronization control signal at the SYNC output terminal. This synchronization control signal controls the synchronous freewheeling power transistor M. 212 During the freewheeling phase of the inductor, it conducts because M 212 The on-state voltage drop is much smaller than that of... Figure 20 The freewheeling diode D1 in the circuit improves system efficiency. Furthermore, the switching power supply system 2100 directly samples M... 211 The on-state voltage is used to detect the current of the power inductor L1, which can further reduce losses and improve system efficiency. The 2100 switching power supply system is suitable for DC-DC scenarios, especially low-voltage, high-current scenarios, and has high conversion efficiency. It is suitable for medium and high power scenarios such as fast charging of consumer electronics and power supply of server CPUs, and can effectively reduce the heat loss of the power supply system and increase the power density.

[0092] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0093] It should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0094] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used to describe embodiments are sometimes modified by the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in this application are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A power controller for a switching power supply system, used to output n output voltage signals based on a single input voltage signal, characterized in that, include: The first input terminal is used to connect to the output terminal of the inductive energy storage element of the switching power supply system; n output branches, each output branch is connected to the first input terminal and is used to output one output voltage signal, where n is a positive integer greater than or equal to 2; The feedback unit is used to generate n feedback signals in a one-to-one correspondence with the n output voltage signals; The second input terminal is used to connect to the inductive energy storage element of the switching power supply system to obtain the current sampling voltage signal of the input voltage signal of the switching power supply system. A modulation control unit is configured to output a modulation control signal based on at least one of the n feedback signals, a reference voltage signal, and the current sampling voltage signal; A driving unit is configured to output a driving signal under the control of the modulation control signal, the driving signal being used to control the on and off of the power switch of the switching power supply system; and The equalization control unit is used to generate n control signals in a one-to-one correspondence with the n feedback signals, and the n control signals are used to control the n output branches to be turned on sequentially in a time-division manner in a one-to-one correspondence.

2. The power controller as described in claim 1, characterized in that, The system includes a first control circuit and a second control circuit. The first control circuit includes the modulation control unit, the drive unit, and the feedback unit. The first control circuit is used to form a first loop with the inductive energy storage element and the power switch of the switching power supply system. The second control circuit includes the n output branches, the feedback unit, and the equalization control unit. The second control circuit is used to form a second loop with the inductive energy storage element. The first loop and the second loop are decoupled from each other.

3. The power controller as described in claim 2, characterized in that, The feedback signal is obtained by voltage division of the corresponding output voltage signal, wherein the ratio of the output voltage signal to the feedback signal is equal to the ratio of the preset voltage value to the reference voltage signal; The first loop is further configured to cause the n output voltage signals to converge to a fixed preset voltage value, and the second loop is further configured to ensure that when the convergence reaches a steady state, the ratio between each output voltage signal and its corresponding preset voltage value is the same.

4. The power controller as described in claim 1, characterized in that, The equalization control unit includes n-1 cascaded loop gain units, wherein the j-th loop gain unit is used to generate the j-th control signal based on the j-th feedback signal and the (j+1)-th feedback signal, where j is a positive integer from 1 to n-1.

5. The power controller as described in claim 4, characterized in that, The equalization control unit further includes a logic unit, which is used to perform logical operations based on the first to the (n-1)th control signals and control pulses to obtain the nth control signal. The control pulses include the entire demagnetization phase of the inductive energy storage element of the switching power supply system within one switching cycle of the power switch.

6. The power controller as described in claim 5, characterized in that, In the first to nth control signals, when the first control signal of two adjacent control signals switches from the on level to the off level, the second control signal switches from the off level to the on level. The nth control signal switches to the off level after the demagnetization stage ends.

7. The power controller as described in claim 4, characterized in that, The equalization control unit further includes a switching element, which is used to switch the nth output branch from the off state to the on state when the (n-1)th control signal switches from the on level to the off level, and switches to the off state after the demagnetization phase of the inductive energy storage element of the switching power supply system ends.

8. The power controller as described in claim 1, characterized in that, The modulation control unit is a PWM control unit, and the modulation control signal is a PWM signal. The PWM control unit includes an energy adjustment unit, a trigger, and a comparator. The energy adjustment unit is used to generate a threshold voltage signal and a set signal based on at least one feedback signal and a reference voltage signal. The set signal, the threshold voltage signal, and the reset signal generated by the comparator from the current sampling voltage signal are respectively used to input the trigger to make the trigger generate the PWM signal. The set signal is used to determine the frequency of the PWM signal, and the threshold voltage signal is used together with the current sampling voltage signal to determine the pulse width of the PWM signal.

9. The power controller as described in claim 8, characterized in that, The energy regulation unit includes n comparators and OR gates. The n feedback signals are respectively input to the n comparators. Each comparator is used to compare the corresponding feedback signal and the reference voltage signal and generate a comparison result. The n comparison results are input to the OR gate to obtain the set signal.

10. The power controller as described in claim 8, characterized in that, The energy regulation unit includes a weighted comparator and n weighted current generating modules. The j-th weighted current generating module is used to generate a weighted current positively correlated with the load size corresponding to the j-th output branch under the control of the j-th control signal. The load is the load connected to the second terminal of the output branch in the switching power supply system. The weighted comparator includes n differential pairs and a current mirror. The inputs of the j-th differential pair are the j-th feedback signal and the reference voltage signal, respectively. The output terminals of the n differential pairs are connected to the input terminal of the current mirror so that the output currents of each differential pair are superimposed at the input terminal of the current mirror to form a weighted error signal. The weighted error signal is used as the set signal, where j is a positive integer from 1 to n-1.

11. The power controller as described in claim 10, characterized in that, The weighted comparator further includes a weighted amplifier, which amplifies the weighted error signal and uses the amplified weighted error signal as the set signal.

12. The power controller as described in claim 8, characterized in that, The energy regulation unit includes: A weighted summation unit is used to perform weighted summation on at least one of the feedback signals and output a weighted summation signal; An operational amplifier includes a first input terminal, a second input terminal, and an output terminal. The first input terminal is used to receive the weighted summation signal, the second input terminal is used to receive the reference voltage signal, the operational amplifier is used to amplify the difference between the weighted summation signal and the reference voltage signal, and outputs an error amplification signal at the output terminal. A compensation network, coupled to the output of the operational amplifier, is used to perform frequency compensation on the error amplification signal to stabilize the loop; A frequency generation unit, coupled to the output of the operational amplifier, is used to generate a set signal with a first frequency based on the error amplification signal; A threshold generation unit, coupled to the output of the operational amplifier, is used to generate the threshold voltage signal based on the error amplification signal. The comparator includes a first comparator input, a second comparator input, and a comparator output. The first comparator input is used to receive the current sampling voltage signal of the input signal of the switching power supply system. The second comparator input is coupled to the output of the threshold generation unit to receive the threshold voltage signal. When the current sampling voltage signal is greater than the threshold voltage signal, the comparator outputs a reset signal through the output, and the reset signal is used to input to the trigger.

13. The power controller as described in claim 8, characterized in that, The modulation control unit is a PFM control unit, the modulation control signal is a PFM signal, and the driving unit is an isolated driving unit. The switching power supply system includes a transformer, the primary winding and the secondary winding of the transformer are not grounded, the primary winding corresponds to the primary ground, the secondary winding corresponds to the secondary ground, the reference ground of the PFM signal is the secondary ground, the PFM signal is coupled to the primary winding through the isolated driving unit to generate the driving signal, and the reference ground of the driving signal is the primary ground.

14. A switching power supply system, characterized in that, include: The power controller as described in any one of claims 1-13; An inductive energy storage element includes a transformer, the transformer including a primary winding and a secondary winding, a first end of the primary winding for receiving an input voltage signal, a first end of the secondary winding connected to a first input terminal of the power controller, and a second end of the secondary winding grounded; A power switch, wherein the first end of the power switch is connected to the second end of the primary winding, the second end of the power switch is grounded through a current sampling resistor and connected to the second input terminal of the power controller, and the control terminal of the power switch is used to receive the drive signal; n output loads are connected one-to-one with the second end of the n output branches; and Each of the n output capacitors is connected in parallel with one of the n output loads.

15. A switching power supply system, characterized in that, include: The power controller as described in any one of claims 1-13; An inductive energy storage element includes a power inductor, a first terminal of which is connected to a second input terminal of a power controller, and the first terminal of which is also connected to the first input terminal of the power controller through a current sampling resistor. The second terminal of the power inductor is connected to the negative terminal of a freewheeling diode, and the positive terminal of the freewheeling diode is grounded. A power switch, wherein the second terminal of the power switch is connected to the second terminal of the power inductor, the first terminal of the power switch is used to receive an input voltage signal, and the control terminal of the power switch is used to receive the drive signal; n output loads are connected one-to-one with the second end of the n output branches; and Each of the n output capacitors is connected in parallel with one of the n output loads.

16. A switching power supply system, characterized in that, include: The power controller as described in any one of claims 1-13; An inductive energy storage element includes a power inductor, wherein a first terminal of the power inductor is connected to a first input terminal of the power controller, and a second terminal of the power inductor is connected to a second input terminal of the power controller. A first power switch, the second end of which is connected to the second end of the power inductor and to the second input terminal of the power controller, the first end of which is used to receive an input voltage signal, and the control terminal of which is used to receive the drive signal; The second power switch has a first terminal connected to the second terminal of the power inductor and the second terminal grounded. The control terminal of the second power switch is connected to the synchronous output terminal of the power controller. The synchronous output terminal is used to output a synchronous control signal to enable the second power switch to conduct during the freewheeling phase of the power inductor. n output loads are connected one-to-one with the second end of the n output branches; and Each of the n output capacitors is connected in parallel with one of the n output loads.

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